Wastewater Term Glossary by jennifer poland

do J

GLOSSARY of terms in the

WASTEWATER INDUSTRY

FOREWORD

This presentation by the Associates Committee of the California Association of Sanitation Agencies CASA is a voluntary effort and

is made possible through the private resources of all CASA Associates The glossary is intended to be used as a general reference guide to terms commonly used in the wastewater industry It is not intended to be a comprehensive resource and the reader is directed to textbook sources for terms which are not Included in this summary version

The

Glossary was

prepared

by CREM

Engineers

Inc with

assistance from Robertson Alexander Luther Esselstein Sheilis and

Wright for legal terms and Bartle Wells Associates and Hood and Strong for financial terms 1

Wastewater Glossary

accidental spills Unplanned release of substances either directly or indirectly in such magnitude that substantial effects on receiving systems will be noted Release is the result of accident acts of nature or operational malfunctions

acrefoot 1 A volume of water 1 ft seep and 1 acre in area or 43 560 cu ft 12333 m 2 A

560 cu ft 1233 43 5 m3 volume of trickling filter medium

activated carbon treatment Treatment process in which water is brought into contact with

highly adsorptive granular or powdered carbon to remove soluble components Process may be applied to raw water primary effluent or chemically clarified wastewater for nonspecific removal of organics or to secondary effluent as a polishing process to remove specific organics activated sludge Sludge withdrawn from a secondary clarifier following the activated sludge process it consists mostly of biomass with some inorganic settleable solids Return sludge is recycled to thehead of the process waste excess sludge is removed for conditioning

activated sludge loading The pounds or kg of biochemical oxygcn demand BOD in the

applied liquid per unit volume of aeration capacity or per pound or kg of activated sludge per

day

aeration period 1 The theoretical time usually expressed in hours during which mixed liquor is subjected to aeration in an aeration tank while undergoing activated sludge treatment It is equal to the volume of the tank divided by the volumetric rate of flow of the wastewater and

return sludge 2 The theoretical time during which water is subjected to aeration aeration tank A tank in which wastewater or other liquid is aerated aerator A device that brings air and a liquid into intimate contact

algae Photosynthetic microscopic plant which in excess can contribute taste and odor to potable water and deplete dissolved oxygen on decomposition

anaerobic lagoon anoxic conditions

A wastewater or sludge treatment process that involves retention under

anaerobic waste treatment

Waste stabilization brought about through the action of

microorganisms in the absence of air or elemental oxygen Usually refers to waste treatment by methane fermentation appurtenances

Machinery appliances or auxiliary structures attached to a main structure to

enable it to function but not considered an integral part of it

backfill I The operation of refilling an excavation usually after some structure has been placed therein 2 The material placed in an excavation in the process of backfilling ball joint A flexible pipe joint made in the shape of a ball or sphere ball valve A simple nonretum valve consisting of a ball resting on a cylindrical seat within a fluid passageway B coil

A member of the coliform group Now classified as E coli

biologically active floe activated sludge

Floc formed by the action of biological agencies for example

biological oxidation The process by which living organisms in the presence of oxygen convert

organic matter into a more stable or a mineral form

biological wastewater treatment

Forms of wastewater treatment in which bacterial or

biochemical action is intensified to stabilize and oxidize the unstable organic matter present Intermittent sand filters trickling filters and activated sludge processes and sludge digestion are examples

BOD 1 Abbreviation for biochemical oxygen demand The quantity of oxygen used in the biochemical oxidation of organic matter in a specified time at a specified temperature and under specified conditions 2 A standard test used in assessing wastewater strength BOD load The BOD content usually expressed in pounds per unit of time of wastewater passing into a waste treatment system or to a body ofwater

breakpoint chlorination

Addition of chlorine to water or wastewater until the chlorine

demand has been satisfied and further additions result in a residual that is directly proportional to

the amount added beyond the breakpoint

building drain Tn plumbing that part of the lowest horizontal piping within a building that conducts water wastewater or storm water to a building sewer

building sewer In plumbing the extension from the building drain to the public sewer or other

place of disposal Also called house connection

California Environmental Quality Act CEQA The California legislative enactment California Public Resources Code 2100 and following which requires public agencies to assess the environmental impacts of public and private projects before governmental authorization of the project is granted

capital assets Assets of a relatively permanent nature

bra apt

aAa

Saar eart LAY a seL e isl ti 4tiat is tar s r 44 10 Jta S Se 1 house

Ut6 l acal Metal

hens tc

tuns Se etc

stn

sty 2

CASA California Association of Sanitation Agencies an organization of various municipal agencies which provide wastewater treatment transportation and disposal in California cesspool

A lined or partially lined underground pit into which raw household wastewater is

discharged and from which the liquid seeps into the surrounding soil Sometimes called leaching

cesspool

cfs The rate of flow of a material in cubic feet per second Used for measurement of water wastewater or gas One cfs equals 4 719 x 10 ms

chemical coagulation

The destabilization and initial aggregation of colloidal and finely

divided suspended matter by the addition of an inorganic coagulant

chemical feeder A device for dispensing a chemical at a predetermined rate for the treatment

of water or wastewater Change in rate of feed may be affected manually or automatically by flowrate changes Feeders are designed for solids liquids or gases

chemical oxidation The oxidation of compounds in wastewater or water by chemical means typical oxidants include ozone chlorine potassium permanganate

chemical oxygen demand COD A quantitative measure of the amount of oxygen required for the chemical oxidation of carbonaceous organic material in wastewater using inorganic dichromate or permanganate salts as oxidants in a two hour test Commonly abbreviated COD cbloramines Compounds of organic or inorganic nitrogen and chlorine

chlorination

The application of chlorine or chlorine compounds to water or wastewater

generally for the purpose of disinfection but frequently for chemical oxidation and odor control

chlorine contact chamber A detention basin provided to diffuse chlorine through water or wastewater and to provide adequate contact time for disinfection

clarified wastewater Wastewater from which most of the settleable solids have been removed by sedimentation Also called settled wastewater

coagulants

A simple electrolyte usually an inorganic salt containing a multivalent cation of

iron aluminum or calcium for example FeCl3 FeC12 Al2 3 CaO Also an inorganic acid SO4 or base which induces coagulation of suspendedsolids

codiposal Joint disposal of wastewater sludge and municipal refuse in one process or facility

Disposal can be intermediate as with incineration or composting or final as with placement in sanitary landfill

In collection systems a sewer to which branch and submain sewers are

utary

connected

so called a trunk sewer In plumbing the public sewer to which a building service is

collection system In wastewater a system of conduits generally underground pipes which

receives and conveys sanitary wastewater and or storm water In water supply a system of conduits or canals used to capture a water supply and convey it to a common point combined sewer A sewer intended to receive both wastewater and storm or surface water

combined sewer system

A sewer system carrying both sanitary wastewaters as well as

wastewaters resulting from storm drainage systems and surface runoffs

combined system A system of conduits generally underground pipes which receives and

conveys both sanitary wastewater and storm water

combined treatment Joint treatment of municipal commercial and industrial wastewaters combined wastewater A mixture of surface runoff and other wastewater such as domestic or industrial wastewater

commercial user All retail stores restaurants office buildings laundries and other private business and service establishments including churches and lodges condemnation A public agency s exercise of the power of eminent domain

connection fee A fee paid by a new system user for the capital costs ofcapacity made available for his use

consolidated grants A consolidated grant is a grant funded under more than one grant authority by EPA or a grant awarded in conjunction with one or more Federal agencies e g Joint

Funded Assistance

construction Any one or more of the following preliminary planning to determine feasibility of treatment works engineering architectural legal fiscal or economic investigations or studies surveys designs plans working drawings specifications procedures other necessary actions

erection building acquisition alteration remodeling improvement or extension of treatment works or inspection or supervision of any of the foregoing items construction grants Financial aid for the construction of publicly owned wastewater treatment facilities or interceptor sewers under federal or state legislation

construction management The overall responsibility for planning organizing and controlling the activities of bidding and construction Specific responsibilities are cost and time control

management planning and negotiation of changes

contact bed 1 An artificial bed of coarse material providing extensive surface area for biological growth in watertight basin Wastewater exposure to the surface may be accomplished by cycling or by continuous flow through controlled inlet and outlet 2 An early type of wastewater filter consisting of a bed of coarse broken stone or similar inert material placed in a 4

watertight tank or basin which can be completely filled with wastewater and then emptied

Operation consists of filling allowing the contents to remain for a short time draining and then allowing the bed to rest The cycle is then repeated A precursor to the trickling filter contamination

The introduction into water of microorganisms chemicals wastes or

wastewater in a concentration that makes the water unfit for its intended use

contour A line ofequal elevation above a specified datum usually mean sea level

contour line A line joining points having or representing equal elevations conventional treatment

Wellknown or well established water or wastewater treatment

processes excluding advanced or tertiary treatment it generally consists of primary and secondary treatment

crude wastewater Wastewater before it receives any treatment Also called raw wastewater

culture

Any organic growth that has been developed intentionally by provision of suitable

nutrients and environment

debt service The amount of money necessary annually a to pay the interest on outstanding debt b to pay the principal of maturing bonded debt not payable from a sinking fund or c to provide a fund for the redemption ofbonds payable from a sinking fund

decomposition of wastewater 1 The breakdown oforganic matter in wastewater by bacterial

action either aerobic or anaerobic 2 Chemical or biological transformation of organic or inorganic materials contained in wastewater

degreasing 1 The process of removing greases and oils from waste wastewater sludge or solid wastes 2 The industrial process of removing grease and oils from machine parts or i ron

products

depressed sewer A section of sewer constructed lower than adjacent sections to pass beneath a valley watercourse or other obstruction It runs full or at pressure greater than atmospheric because its crown is depressed below the hydraulic grade line

design analysis In engineering reports the tabulation and consideration of the physical data present requirements and probable future requirements pertaining to an engineering project It should include the main features and principles ofthe design

dewatered sludge The solid residue remaining after removal of water from a wet sludge by

draining or filtering Dewatering is distinguished from thickening in that dewatcred sludge may

be transported by solids handling procedures

dewatering The process of partially removing water may refer to removal of water from a basin tank reservoir or other storage unit or to separation of water from solid material

digested sludge Sludge digested under either aerobic or anaerobic conditions until the volatile content has been reduced to the point at which the solids are relatively nonputrescible and inoffensive

dilution Disposal of wastewater or treated effluent by discharge to and dispersion in a receiving water with resulting reduction in concentrations of constituents while accounting for background levels and natural assimilation processes

dilution factor The ratio ofthe quantity of untreated wastewater or partly or completely treated

effluent to the average quantity ofdiluting water available at the point of disposal or at any point

underconsideration usually expressed in percentage Also called available dilution discharge

With respect to wastewaters the release of treated partially treated or untreated

wastewaters into the environment whether accidentally or by design

disinfected wastewater Wastewater to which a disinfecting agent has been added

dissolved oxygen The oxygen dissolved in water wastewater or other liquid usually expressed

in milligrams per liter or percent of saturation Abbreviated DO

dissolved solids Solids in solution that cannot be removed be filtration for example NaC1 and other salts that must be determined by evaporation

diurnal fluctuation 1 The cyclic rise and fall of the water table or streamflow during a 24hr period in response to changes in evapotransportation draft from groundwater 2 Any daily variation in a groundwater characteristic such as flow BOD or suspended solids

diversion manhole A manhole equipped with a device for diverting a portion of the total flow to another sewer or conduit

domestic A term used to distinguish municipal household water or wastewater services from commercial and industrial water or wastewater Term sometimes used to include commercial component

domestic wastewater

Wastewater derived principally from dwellings business buildings

institutions and the like It may or may not contain groundwater surface water or storm water domestic wastewater treatment Reduction or removal of insoluble and dissolved constituents from the liquid wastes from dwelling business building institutions etc

drying beds Confined underdrained shallow layers of sand or gravel on which wet sludge is distributed for draining and air drying Also applied to underdrained shallow dyked earthen structures used for drying sludge

dry weather flow 1 The flow of wastewater in a combined sewer during dry weather Such

flow consists mainly of wastewater with no stone water included 2 The flow of water in a stream during dry weather usually contributed entirely by groundwater E coil

Abbreviation of Escherichia coli

effluent 1 A liquid which flows out of a process or confined space 2 Wastewater or other

liquid partially or completely treated or in its natural state flowing out of a reservoir basin

treatment plant or industrial treatment plant or part thereof 3 An outflowing branch of a main stream or lake 4 An emission of gas

effluent quality The physical biological and chemical characteristics of wastewater or other

liquid flowing out of a basin reservoir pipe or treatment plant

effluent standard Specification of the allowable concentration or mass of a constituent which

may be discharged

eminent domain The right and power of a public agency to acquire another person sproperty for a public use For state and local government agencies the right and power are exercised

under the Eminent Domain Law California Code of Civil Procedure 1230 010 and following equalization

In wastewater systems the storage and controlled release of wastewaters to

treatment processes at a controlled rate determined by the capacity ofthe processes or at a rate

proportional to the flow in the receiving stream used to smooth out variations in temperature and composition as well as flow equivalent dwelling unit EDIT Any service unit A standard service unit is defined as one

single family dwelling unit or its equivalent A standard service unit is assumed to discharge wastewater at a flow and strength equal to that ofan average single family dwelling unit

escherichia coli One of the species of bacteria in the fecal coliform group It is found in large numbers in the gastrointestinal tract and feces of warnblooded animals and man Its presence is considered indicative of fresh fecal contamination and it is used as an indicator organism for the

presence of less easily detected pathogenic bacteria Abbreviated E Coli

faculative bacteria

Bacteria which can adapt themselves to grow and metabolize in the

presence as well as the absence of oxygen

fecal coliform Aerobic and faculative Gram negative honspore forming rod shaped bacteria capable ofgrowth at 44 5C and associated with fecal matter of warmblooded animals

feces Excrement from the gastrointestinal tract consisting of residue from food digestion and bacterial action filamentous sludge

Activated sludge characterized by excessive growth of filamentous

bacteria resulting in poor sludge settling

filter A device or structure for removing solid or colloidal material usually of a type that cannot be removed by sedimentation from water wastewater or other liquid The liquid is

passed through a filtering medium usually a granular material but sometimes finely woven cloth unglazed porcelain or specially prepared paper There are many types of filters used in water and wastewater treatment

filtered wastewater Wastewater that has passed through a mechanical filtering process but not

through a trickling filter bed

filter press A plate and frame press operated mechanically to produce a semisolid cake from a slurry

fiveday BOD BOD5

That part of oxygen demand usually associated with biochemical

oxidation of carbonaceous material with 5 days at 20 C First stage of biochemical oxygen demand floc

Collections of small particles agglomerated into larger more easily settleable particles

through chemical physical or biological treatment

flocculants Watersoluble organic polyelectrolytes that are used alone or in conjunction with inorganic coagulants such as aluminum or iron salts to agglomerate solids present in water or wastewater to form large dense floc particles which settle rapidly

flocculation In water and wastewater treatment the agglomeration of colloidal and finely divided suspended matter after coagulation by gentle stirring by either mechanical or hydraulic means In biological wastewater treatment where coagulation is not used agglomerates may be accomplished biologically

flocculation agent A coagulating substance which when added to water forms a flocculent

precipitate which will entrain suspended matter and expedite sedimentation examples are alum ferrous sulfate and lime

flow 1 The movement of a stream of water or other fluid from place to place movement of silt water sand or other material 2 The fluid which is in motion 3 The quantity or rate of movement of a fluid discharge total quantity carried by a stream 4 To issue forth or discharge 5 The liquid or amount ofliquid per unit time passing a given point flow equalization

Transient storage of wastewater for release to a sewer system or treatment

plant at a controlled rate to provide a reasonably uniform flow for treatment

gpd The rate of water wastewater or other flow measured in U S gallons per day gpm The rate of water wastewater or other flow measured in U S gallons per minute grab sample Sample taken at a given place and time It may be representative of the flow

grant regulations An award of funds by a State grant contract or a Federal grant agreement grant contract The written agreement and any amendments thereto between the S WRC13 and an applicant in which the terms provisions and conditions governing the grant are stated

grantee

An applicant who has received a grant A grantee may be a municipality inter

municipality agency state or interstate agency

grant modifications

Any written alteration in the grant amount grant terms or conditions

budget or project period or other administrative technical or financial agreement whether accomplished by unilateral action of the grantee or the Government in accordance with a provision of the grant agreement or by mutual action of the parties to the grant

grant processing fee A fee charged by the State Board to each grantee for services provided by the State Board in administration of the grant program

gravity system

1 A system of conduits open or closed in which the liquid runs on

descending gradients from source to outlet and where no pumping is required 2 A water distribution system in which no pumping is required

grease

oil

In wastewater a group of substances including fats waxes free fatty acids

calcium and magnesium soaps mineral oils and certain other nonfatty materials Water insoluble

organic compounds of plant and animal origins or industrial wastes that can be removed by natural flotation skimming

grease interceptor trap

In plumbing a receptacle designed to collect and retain grease and

fatty substances normally found in kitchen or similar wastes It is installed in the drainage system between the kitchen or other point of production of the waste and the building sewer grease removal tank A tank designed to facilitate the flotation of oil and grease provided with a device for removal

grease skimmer A device for removing floating grease or scum from the surface of wastewater in a tank

grease trap

A device for separation of grease from wastewater by flotation so that it can be

removed from the surface

green sludge Sludge in which decomposition is little advanced Usually called fresh sludge

grinder

A device used to reduce the particle size of wastewater solids so that they may be

returned to the wastewater flow or processed for later treatment

grit The heavy suspended mineral matter present in water or wastewater such as sand gravel

cinders It is removed in a pretreatment unit called a grit chamber to avoid abrasion and wearing of subsequent treatment devices

grit catcher A chamber usually placed at the upper end of a depressed sewer or at other points

on combined or storm sewers where wear from grit is possible the chamber is sized and shaped to reduce the velocity offlow through it and thus permit the settling out of grit Also called sand chamber

grit chamber

A detention chamber or an enlargement of a sewer designed to reduce the

velocity of flow of the liquid to permit the separation of mineral from organic solids by

differential sedimentation

grit separator

Any process of device which is designed to separate grit from a water or

wastewater stream

grit washer A device for washing organic matter out of grit

head 1 The height of the free surface of fluid above any point in a hydraulic system a measure of the pressure or force exerted by the fluid 2 The energy either kinetic or potential possessed by each unit weight of a liquid expressed as the vertical height through which a unit weight would have to fall to release the average energy possessed It is used in various

compound terms such as pressure head velocity head and loss of head 3 The upper end of anything as headworks 4 The source of anything as headwater 5 A comparatively high promontory with either a cliff or steep face extending into a large body of water such as a sea or lake An unnamed head is usually called a headland

bead loss

Energy losses due to the resistance of flow of fluids May be classified into conduit

surface and conduit form losses

headworks 1 All the structures and devices located at the head or diversion point of a conduit

or canal The tern as used is practically synonymous with diversion works an intake heading 2 The initial structures and devices of a water or wastewater treatment plant heavy metals Metals that can be precipitated by hydrogen sulfide in acid solution for example lead silver gold mercury bismuth copper heavy sludge Sludge in fluid form but with a relatively low moisture content house connection

The pipe carrying the wastewater from the building to a common sewer

Also called building sewer house sewer

house drain

That part of the lowest horizontal piping of a drainage system which receives the

discharge from soil waste and other drainage pipes inside the walls of the building and conveys it to the building sewer house sewer the pipe that begins five feet outside the inner face of the building wall Also called building drain

humus sludge

I Sludge deposited in final or secondary settling tanks following trickling

filters or contact beds 2 Sludge resembling humus in appearance

hydraulic loading

The amount ofwater or wastewater applied to a given treatment process

usually expressed as volume per unit time or volume per unit time per unit surface area Imhoff tank A deep two storied treatment tank originally patented by Karl Imhoff It consists of an upper continuousflow sedimentation chamber and a lower sludge digestion chamber The

floor ofthe upper chamber slopes steeply to trapped slots through which solids may slide into the lower chamber The lower chamber receives no fresh wastewater directly but is provided with gas vents and with means for drawing digested sludge from near the bottom industrial waste Generally liquid solid or gaseous wastes originating from the manufacture of specific products Such wastes are usually more concentrated more variable in content and rate and require more extensive or different treatment than municipal waste industrial wastewater treatment Treatment of wastewater by industry The three classes of wastewater treated are manufacturing wastes cooling process wastes and sanitary wastes influent Water wastewater or other liquid flowing into a reservoir basin or treatment plant or treatment process

inverted siphon

A pipeline crossing a depression or passing under a structure and having a

reversal in grade on a portion ofthe line thus creating a V or Ushaped section of conduit The

line is under positive pressure from inlet to outlet and should not be confused with a siphon Also called depressed sewer

ion

A charged atom molecule or radical the migration of which affects the transport of

electricity through an electrolyte or to a certain extent through a gas An atom or molecule that has lost or gained one or more electrons

ion exchange resins Insoluble polymers used in water and wastewater treatment with appended functional groups that are capable of exchanging acceptable cations or anions for less desirable ions

jetting 1 A method of well sinking in which the casing is sunk by driving while the material inside is washed out by a water Jet and carried to the top of the casing 2 A method of sinking

piles by means of a water jet 3 A method of inserting well points by means of a water jet 4 A method of consolidating unconsolidated backfill by means of a water jet Also called jet joint treatment The combined treatment of municipal and industrial wastewaters junction manhole A manhole at the confluence of two or more sewers

lamp hole A small vertical pipe or shaft extending from the surface of the ground to a sewer wherein a light may be lowered for the purpose ofinspection Rarely used in present practice

land application The recycling treatment or disposal of wastewater or wastewater solids to the land under controlled conditions

land disposal Application of raw or treated wastewater sludges or solid waste to soils and or substrata without production of usable agricultural products

landfill The disposal of solid wastes or sludges by placing on land compacting and covering as appropriate with a thin layer of soil

land filtration The distribution of wastewater in numerous ditches cutting up farm land into beds which are kept moist by horizontal seepage from the ditches Also called hed irrigation

lateral 1 Pertaining to the side 2 A ditch pipe or other conduit entering or leaving a water main from the side 3 A secondary conduit diverting water from a main conduit for delivery to distribution 4 A sewer which discharges into a branch or other sewer and has no common sewer tributary to it

gairlik sewer that discharges into a branch or other sewer and has no othersewer and has no common sewer tributary to it leach To extract a soluble substance to lose soluble material through a filtering medium

leaching cesspool A lined or partially lined underground pit into which raw household wastewater is discharged and from which the liquid seeps into the surrounding soil Also called cesspool

levy

1 To impose taxes special assessments or service charges for the support of

governmental activities 2 The total amount of taxes special assessments or service charges imposed by a government

liabilities

Debt or other legal obligation arising out of transactions in the past which must be

liquidated renewed or refimded at some future date This term does not include encumbrances

lift station

A structure that contains pumps and appurtenant piping valves and other

mechanical and electrical equipment for pumping water wastewater or other liquid Also called pump station

line manhole A manhole on a sewer at a point where no other sewers connect It is often located at a point where the sewer changes direction either in line or grade

liquid chlorine Elemental chlorine converted to a liquid state by compression and refrigeration of the dry purified gas Liquid chlorine is shipped under pressure in steel containers

local sewering agency Any public agency or private corporation responsible for the collection and disposal of wastewater to the District sewerage facilities duly authorized under the laws of the State of California to construct and or maintain public sewers

loss of head 1 The decrease in energy head between two points resulting from friction bend obstruction expansion or any other cause It does not include changes in the elevation of the

hydraulic grade line unless the hydraulic and energy grade lines parallel each other 2 The difference between the total heads at two points in a hydraulic system magnetic separation A physical treatment process for removing magnetic suspended solids from a liquid by applying a magnetic field 1 In larger systems the principal sewer to which branch sewers and submains are

a so called trunk sewer In small systems a sewer to which one or more branch sewers are tributary 2 In plumbing the public sewer to which the house or building sewer is connected

manhole

1 A structure atop an opening in a gravity sewer to permit entry for servicing

Usually placed at all points of change in sewer grade and at least every 300 to 400 feet along the line 2 An opening in the top or side of an enclosed vessel to permit human entry manhole infiltration

The entry of extraneous groundwater through manhole cracks or joints

manhole inflow The admittance of surface waters through manhole cover openings or seals manhole invert The lowest point of the interior of the manhole at any crosssection manufacturing wastes

The liquid wastes from industrial processes as distinct from domestic

or sanitary wastes Also called industrial wastes

mean cell residence time 1VICRT Average time that a given unit of cell mass stays in the activated sludge aeration tank It is usually calculated as the ratio of the total mixed liquor suspended solids in the aeration tank to that of wastage mean sea level The mean plane about which the tide oscillates the average height of the sea for all stages of the tide

mechanical aeration 1 The mixing by mechanical means of wastewater and activated sludge in the aeration tank of the activated sludge process to bring fresh surfaces of liquid into

contact with the atmosphere 2 The introduction of atmospheric oxygen into a liquid by the mechanical action of paddle paddle wheel spray or turbine mechanisms mechanical agitation

The introduction of atmospheric oxygen into a liquid by the mechanical

action of paddle paddle wheel spray or turbine mechanisms

mechanically cleaned screen

A screen equipped with mechanical cleaning apparatus for

removal of retained solids

membrane filtration

1 A method of quantitative or qualitative analysis of bacterial or

particulate matter in a water sample by filtration through a membrane capable of retaining

bacteria 2 A technique used in water and wastewater treatment

mesh

One of the openings or spaces in a screen The value of the mesh is usually given as a

number of openings per linear inch This gives no recognition to the diameter of the wire and thus the mesh number does not always have a relationship to the size of the hole mesh screen

A screen composed of woven fabric of any of various materials

mesophilic digestion Digestion by biological action at 27 C to 38 C 80 F to 100 F methane A colorless odorless flammable gaseous hydrocarbon CH4 present in natural gas

and formed by the anaerobic decomposition of organic matter or produced artificially by heating carbon monoxide and hydrogen over a nickel catalyst

methane fermentation A reaction sequence that produces methane during the anaerobic decomposition of organic waste In the fast phase acid forming bacteria produce acetic acid in the second methane bacteria use this acid and carbon dioxide to produce methane Fermentation

resulting in conversion of organicmatter into methane gas methylene blue active substance MBAS

Anionic surfactants including linear alkylate

sulfonate LAS and alkyl sulfate which react with methylene blue to form a bluechloroform soluble complex the intensity of color is proportional to concentration

mgd Million gallons per day a measure of flow equivalent to 1 547 cfs 681 gpm 3785 cu m I Milligrams per liter a measure of concentration equivalent to and replacing ppm in the mg case of dilute solutions

microbiology

Study of microscopic organisms of living matter and their processes

microorganisms

Microscopic organisms either plant or animal invisible or barely visible to

the naked eye Examples are algae bacteria fungi protozoa and viruses

mixed liquor

A mixture of raw or settled wastewater and activated sludge contained in an

aeration tank in the activated sludge process mixed liquor suspended solids MLSS

The concentration of suspended solids in activated

sludge mixed liquor expressed in milligrams per liter Commonly used in connection with activated sludge aeration units

mixed liquor volatile suspended solids MLVSS

That fraction of the suspended solids in

activated sludge mixed liquor that can be driven off by combustion at 550 C it indicates the

concentration of active microorganisms available for biological oxidation multi filter beds A filtration apparatus consisting of two or more media such as media anthracite and sand through which wastewater flows and by which it is cleansed Media may be intermixed or segregated

multiple hearth furnace An incinerator consisting of several vertically stacked hearths Wet sludge is fed into the top hearth and is dried by hot gases produced by the combustion of sludge

on lower hearths The sludge gradually moves downward until it reaches a point where it ignites Furnaces of this type are also used to dry sludge in this case the sludge does not ignite and an outside fuel source is required

multiplehearth incinerator

A counter current type of incinerator frequently used to dry and

burn partially burned sludges Heated air and products of combustion pass by finely pulverized sludges that is continuously raked to expose fresh surfaces

multiplestage sludge digestion

The digestion of waste sludge progressively in two or more

tanks arranged in series

municipality A city town borough county parish district association or other public body including an intermunicipal agency of two or more of the foregoing entities created by or pursuant to State law an Indian tribe an authorized Indian tribal organization having jurisdiction over disposal of sewage industrial wastes or other wastes or a designated and approved management agency under Section 208 of the Act This definition excludes a special district such as a school district which does not have as one of its principal responsibilities the treatment transport or disposal of liquid wastes

negative head 1 The loss of head in excess of the static head a partial vacuum 2 A condition of negative pressure produced by clogging ofrapid sand filters near the end of a filter run

nitrification The oxidation of ammonia nitrogen to nitrate nitrogen in wastewater by biological or chemical reactions

nitrobacteria Bacteria capable of oxidizing nitrogenous material nitrogen An essential nutrient that is often present in wastewater as ammonia nitrate nitrite and organic nitrogen The concentrations of each form and the sum total nitrogen are expressed as mg 1 elemental nitrogen Also present in some groundwater as nitrate and in some polluted groundwater in other forms

nitrogen fixation

The utilization of free nitrogen gas in the fonnation of nitrogen by

appropriate biological activity i

nitrogenous oxygen demand NOD A quantitative measure of the amount of oxygen required for the biological oxidation of nitrogenous material such as ammonia nitrogen and organic nitrogen in wastewater usually measured after the carbonaceous oxygen demand has been satisfied

noncompliance The failure to act in accordance with the laws regulations and contractual terms governing financial assistance that an entity received from a governmental agency

n000perating expenses Proprietary fund expenses which are not directly related to the fund s primary service activities

nutrient Any substance that is assimilated by organisms and promotes growth generally applied to nitrogen and phosphorus in wastewater but also to other essential and trace elements odor control 1 In water treatment the elimination or reduction of odors in a water supply by aeration algae elimination superehlorination activated carbon treatment and other methods 2 In wastewater treatment the prevention or reduction of objectionable odors by chlorination aeration or other processes or by masking with chemical aerosols

offset manhole

A manhole located tangentially to the sewer line rather than on the sewer

centerline

operation and maintenance O M Operation is the organized procedure for causing a piece of equipment a treatment plant or other facility or system to perform its intended function but

not including the initial building or installation of the unit Maintenance is the organized procedure for keeping the equipment plant facility or system in such condition that it is able to continually and reliably perform its intended function operators

Persons employed in operating a treatment facility

operator training

An educational program for the instruction and development of treatment

plant operators

ordinance A formal written order of a public agency s legislative body usually for the purpose of establishing agency policies or determining the rights of persons having business with the agency usually entered in the minutes of the meeting of the legislative body and effective upon adoption

organic matter

Chemical substances of animal or vegetable origin or more correctly

containing carbon and hydrogen osmosis The process of diffusion of a solvent through a semipermeable membrane from a solution of lower to one of higher concentration

outfall

1 The point location or structure where wastewater or drainage discharges from a

sewer drain or other conduit 2 The conduit leading to the ultimate disposal area

outfall sewer

A sewer that receives wastewater from a collecting system or from a treatment

plant and carries it to a point of final discharge

overflow manhole

A manhole at which water overflows from a collection system They are

used primarily in combined sewerage systems to divert excess flows that exceed the capacity of the downstream collection system or at pumping stations or treatment plants to divert flows that cannot be accommodated under emergency conditions In either case the diverted flows are conveyed essentially untreated to the nearest watercourse

overhead Those elements of indirect cost necessary to produce an article or perform a service but of such nature that the amount applied to each unit of product or service cannot be determined readily or accurately and is thus usually allocated on some arbitrary basis Normally overhead relates to those objects of expenditure which do not become an integral part of the finished product or service such as rent light supplies management supervision oxidation ditch

A secondary wastewater treatment facility that uses an oval channel with a

rotor placed across it to provide aeration and circulation The screened wastewater in the ditch is aerated by the rotor and circulated at about 1 fps to 2 fps oxidized sludge Sludge in which the organic matter has been stabilized by chemical or biological oxidation oxidized wastewater Wastewater in which the organic matter has been stabilized

oxygen

A chemical element necessary for biological oxidation It comprises approximately

20 of the atmosphere

oxygenation capacity

In treatment processes a measure of the ability of an aerator to supply

oxygen to a liquid oxygen balance

1 The dissolved oxygen level at any point in a stream resulting from the

opposing forces of deoxygenation and reaeration 2 The relation between the biochemical oxygen demand of a wastewater or treatment plant effluent and the oxygen available in the diluting water

ozonation

The process of contacting water wastewater or air with ozone for purposes of

disinfection oxidation orodor control

ozone Oxygen in a molecular fox u with three atoms of oxygen forming each molecule 02 package treatment plant

A small wastewater treatment plant often fabricated at the

s factory hauled to the site and installed as one facility The package may be either manufacturer a small primary or a secondary wastewater treatment plant package wastewater plants

Prefabricated structures that perform one or more wastewater

treatment processes

Parshall flume

A calibrated device developed by Parshall for measuring the flow of liquid in

an open conduit It consists essentially of a contracting length a throat and an expanding length At the throat is a sill over which the flow passes at Belanger s critical depth The upper and lower heads are measured at a definite distance from the sill

particles Generally discrete solids suspended in water or wastewater which can vary widely in size shape density and charge Colloidal and dispersed particles are artificially agglomerated by processes of coagulation and flocculation

parts per million The number of weight or volume units of a minor constituent present with each one million units of a solution or mixture The more specific term milligrams per liter is prefen

pathogenic bacteria Bacteria that cause disease in the host organism by their parasitic growth pathogens

Pathogenic or disease producing organisms

peak demand

The maximum momentary load placed on a water or wastewater plant or

pumping station or on an electric generating plant or system This is usually the maximum average load in one hour or less but may be specified as instantaneous or with some other short time period percentage reduction

The ratio of material removed from water or wastewater by treatment to

the material originally present expressed as a percentage percolation 1 The flow or trickling of a liquid downward through a contact or filtering medium The liquid may or may not fill the pores of the medium Also called filtration 2 The movement or flow ofwater through the interstices or the pores of a soil or other porous medium 3 The movement of groundwater in streamline flow in any direction through small interconnected and saturated interstices of rock or earth principally of capillary size 4 The water lost from an unlined conduit through its sides and bed

permeability

1 The property of a material that permits appreciable movement of water

through it when it is saturated and the movement is actuated by hydrostatic pressure of the magnitude normally encountered in natural subsurface water Perviousness is sometimes used in the same sense as permeability 2 The capacity of a rock or rock material to transmit a fluid

pH A measure of the hydrogenion concentration in a solution expressed as the logarithm base ten of the reciprocal of the hydrogen ion concentration in gram moles per liter On the pH

scale 014 a value of 7 at 25 C represents a neutral condition Decreasing values below 7 indicate increasing hydrogenion concentration acidity increasing values above 7 indicate

decreasing hydrogenion concentration alkalinity

phenolic compounds

Hydroxy derivatives of benzene The simplest phenolic compound is

hydroxy benzene C6H

phosphorus An essential chemical element and nutrient for all life forms Occurs in orthophosphate pyrophosphate tripolyphosphate and organic phosphate forms Each of these

forms and their sum total phosphorus is expressed as elemental phosphorus physical adsorption

The accumulation or concentration of substances adsorbate at a surface

or interface with another substance adsorbent by physical attraction and interaction physical analysis

The examination of water and wastewater to determine physical

characteristics such as temperature turbidity color odors taste physical chemical treatment

Treatment of wastewaters by unit processes other than those

based on microbiological activity Unit processes commonly included are precipitation with coagulants flocculation with or without chemical flocculants filtration adsorption chemical oxidations air stripping ion exchange reverse osmosis and several others

physical waste treatment process Racks screens comminutors sedimentation and flotation Chemical or biological reactions are not an important part of the process pilotplant studies

Evaluation on a scale larger than laboratoryscale but smaller than full

scale of the amenability of wastewater to treatment with particular operations or processes pipe bedding The surface and or material on which pipe rests in a ditch Pitot tube A device for measuring the velocity of flowing fluid by using the velocity head of the stream as an index of velocity It consists essentially of an orifice held to pointupstream and

connected with a tube in which the impact pressure due to velocity head may be observed and measured It also may be constructed with an upstream and downstream orifice or with an orifice pointing upstream to measure the velocity head or pressure and piezometer holes in a coaxial tube to measure the static head or pressure in which case the difference in pressure is the index of velocity plain sedimentation

The sedimentation of suspended matter in a liquid unaided by chemicals

or other special means and without provision for the decomposition of deposited solids in contact with the wastewater

plankton 1 Small usually microscopic plants phytoplankton and animals zooplankton in aquatic systems 2 The aggregate of passively floating drifting weakly motile organisms in a body of water

plant hydraulic capacity

The level of flow into a plant above which the system is

hydraulically overloaded plantscale studies Fullscale evaluation of whether or not a particular wastewater is amenable to treatment with particular operation or processes

plate press A filter press consisting of a number of parallel plate units lined with filter cloth which rests on drainage channels in the plats The pressure is exerted by the pumping of solids into chambers so created between the cloths The operation is caned out in batches

plug flow Flow in which fluid particles are discharged from a tank or pipe in the same order in which they entered it The particles retain their discrete identities and remain in the tank for a time equal to the theoretical detention time

pneumatic ejector

A device for raising wastewater sludge or other liquid by alternately

admitting it through an inward swinging check valve into the bottom of an airtight pot and then discharging it through an outward swinging check valve by admitting compressed air to the pot above the liquid point source Any discernible confined or discrete conveyance from which pollutants are or may be discharged including but not limited to any pipe ditch channel tunnel conduit well

container rolling stock concentrated animal feeding operation or vessel or other floating craft pollution

1 Specific impairment of water quality by agricultural domestic or industrial

wastes including thermal and atomic wastes to a degree that has an adverse effect upon any beneficial use of water 2 The addition to a natural body of water of any material which diminishes the optimal economic use of the water body by the population which it serves and has an adverse effect on the surrounding environment

pollutional load

1 The quantity of material in a waste stream which requires treatment or

exerts an effect on the receiving system 2 The quantity of material carved in a body of water which exerts a detrimental effect on some subsequent use of that water

polynuclear aromatic hydrocarbons PAR One of several classes of petroleum based persistent organic pollutants that are released into the environment in large quantities due in large part to human activities Some are known to be potent carcinogens in mammals

polyvinyl chloride PVC An artificial polymer made from vinyl chloride monomer CH CHCI and frequently used in pipes sheets and vessels for transport containment and treatment in water and wastewater facilities

pond

A body of water of limited size either naturally or artificially confined and usually

smaller than a lake

pool 1 A small and rather deep body of relatively quiet water as a pool in a stream 2 A small body of standing or stagnant water a puddle population equivalent The estimated population which would contribute a given amount of a specific waste parameter BOD5 suspended solids flow usually applied to industrial waste

Domestic wastewater contains material that consumes on the average 0 17 lb 0 08 kg of oxygen per capita per day as measured by the standard BOD test For example if an industry

discharges 1 000 pounds 454 kg of 1300 per day its waste is equivalent to the domestic wastewater from 6 000 persons 0 000 1 1 7 approx 6 000 Porter Cologne Water Quality Control Act The California legislative enactment California

Water Code 1300 and following which contains the principal laws governing the discharge of wastewaters in the State

post aeration

The addition of air to plant effluent to increase the oxygen concentration of the

treated wastewater

postchlorination

The application of chlorine to water or wastewater subsequent to any

treatment including prechlorination

ppm Parts per million a unit of concentration on a weight of volume basis Obsolete replaced by mg1

prechlorination The application of chlorine to water or wastewater at or near treatment plant entrance Often used after bar screens and grit chambers to control odors in primary settling tanks

precipitation

1 The total measurable supply of water received directly from clouds as rain

hail or sleet usually expressed as depth in a day month or year and designated as daily monthly or annual precipitation 2 The process by which atmospheric moisture is discharged onto a land or water surface 3 The phenomenon that occurs when a substance in solution is chemically transformed into an insoluble form 4 The conversion of dissolved solids into suspended solids which may be concentrated subsequently by flocculation and sedimentation See also phosphorus removal 5 The removal of fine particles from an airstream using electrostatically charged plates

preliminary treatment

1 The conditioning of a waste at its source before discharge into a

sewer system to remove or to neutralize substances injurious to sewers and subsequent treatment

process or to effect a partial reduction in load on the treatment process 2 Unit operations such as screening comminution and grit removal that prepare the wastewater for subsequent major treatment

press filter A press operated mechanically for partially dewatering sludge pressure filter

1 An enclosed vessel having a vertical or horizontal cylinder of iron steel

wood or other material containing granular media through which liquid is forced under pressure 2 Mechanical filter for partiallydewatering sludge pressure grouting

The placing of grout a watery mixture of either Portland cement and water

or of various organic chemicals which hardens in place under pressure in void spaces in a structure in soil or rock adjacent to a structure or in and around underground pipes to strengthen the structure or make it more watertight

pressure main Pressurized sewer lines that deliver wastewater from a pumping station to a treatment plant a receiving stream or a higher point in the system Also called force main pretreatment 1 Any water or wastewater treatment process that precedes primary treatment may include aeration equalization pH adjustment grit removal grease removal screening skimming comminution or other processes 2 The treatment of industrial wastewater at its

source before discharge to municipal collection systems primary effluent The liquid portion of wastewater leaving primary treatment

primary settling tank The first settling tank for the removal of settleable solids through which wastewater is passed in a treatment works primary sludge Sludge obtained from aprimaary settling tank primary treatment 1 The first major treatment in a wastewater treatment facility usually sedimentation but not biological oxidation 2 The removal of a substantial amount of suspended matter but little or no colloidal and dissolved matter 3 Wastewater treatment processes usually consisting of clarification with or without chemical treatment to accomplish solidliquid separation

primary wastewater treatment Also called preliminary wastewater treatment Unit processes consisting of one or more of the following physical and or chemical operations screening comminution and grinding grit removal skimming preaeration flocculation sedimentation flotation precipitation sludge pumping and disinfection Commonly applied to treatment that consists chiefly of clarification followed by removal treatment and disposal of sludge

process One or a series of defined steps or operations to accomplish a set purpose process water

Water that conies in contact with an end product or with materials incorporated

in an end product

project

The scope of work for which Federal assistance is awarded by a grant or grant

amendment 40 CFR 35 90516

public sewer A common sewer controlled by a governmental agency or public utility public use of water

The use of water by any agency engaged in the development and

distribution of water when such water is offered to all consumers who can be served under their

water system and who may apply for this service up to the full capacity of such system public water supply

Either a community or non community water system which provides

piped water to the public for human consumption if the system has at least five service

connections or serves an average of at least 25 individuals daily at least 60 days out ofthe year The term includes 1 collection treatment storage and distribution facilities under control of the

supplier and 2 collection or pretreatment storage facilities not under such control

public works Projects undertaken by or for a public agency to construct publicly owned capital improvements

pump

A mechanical device for causing flow for raising or lifting water or other fluid or for

applying pressure to fluids pump characteristic curve

A curve or curves showing the interrelation of speed dynamic

head capacity brake horsepower and efficiency of a pump pump efficiency The ratio of energy converted into useful work to the energy applied to the pump shalt or the energy difference in the water at the discharge and suction nozzles divided by power input at the pump shaft

purification

The removal of objectionable matter from water by natural or artificial methods

putrefaction Biological decomposition usually of organic matter with the production of ill smelling products associated with anaerobic conditions putrescibility

1 The relative tendency of organic matter to undergo decomposition in the

absence of oxygen 2 The susceptibility of wastewaters effluent or sludge to putrefaction 3 In water or wastewater analysis the stability of a polluted water or raw or partially treated wastewater

pyrolysis The destructive distillation of organic compounds in an oxygenfree environment converting the organic matter into gases liquids and char rack

A device fixed in place and used to return or remove suspended or floating solids from

wastewater and composed of parallel bars evenly spaced

rapid filter A rapid sand filter or pressure filter rapid sand filtration A downflow staticbed water filtering process using batch or semicontinuous operation and generally using as the single filtration medium Effective particle

sizes range from 0 35 mm to 0 8 mm with uniformity coefficients between 1 3 and 1 7 Filter cleaning is usually effected by reversing flow through the filter medium raw sludge Settled sludge promptly removed from sedimentation tanks before decomposition has much advanced Frequently referred to as undigested sludge raw wastewater Wastewater before it receives any treatment reactor

The container vessel or tank in which a chemical and biological reaction is carried out

reaeration

The absorption of oxygen into water under conditions of oxygen deficiency

receiving water A river lake ocean or other watercourse into which wastewater or treated effluent is discharged

recharge 1 Addition of water to the zone of saturation from precipitation infiltration from surface streams and other sources 2 To inject treated water into underground strata to replenish groundwater and or prevent land collapse or salt water intrusion

reclaimed wastewater Wastewater used for some beneficial purpose usually after some degree of treatment tailored to the intended purpose reclamation The operation or process of changing the condition or characteristics of land so that improved utilization can be achieved This may be accomplished by various means such as

irrigation of arid land drainage of swamp or waterlogged land protection from flood menace of land constantly subject to overflow refuse

Generally all solid waste collected periodically for disposal

regeneration 1 In ion exchange the process of restoring an ion exchange material to the state

employed for adsorption 2 The periodic restoration of exchange capacity of ion exchange media used in water treatment

Region IX of EPA An administrative region of EPA regulating the air land and water quality in the states of California Arizona Nevada and Hawaii relief sewer

1 A sewer built to carry the flows in excess of the capacity of an existing sewer

2 A sewer intended to carry a portion of the flow from a district in which the existing sewers are of insufficient capacity and thus prevent overtaxing the latter

residual chlorine

Chlorine remaining in water or wastewater at the end of a specified contact

period as combined or free chlorine

residue 1 The equilibrium quantity of a compound or element remaining in an organism after uptake and clearance 2 The dry solids remaining after evaporation responsible agency

For purposes of CEQA any public agency other than the lead agency

which has discretion or approval power over a project

retention time

The period that water or wastewater at a given hydraulic loading will be

retained in a reactor unit process or facility returned sludge Settled activated sludge returned to mix with incoming raw or primary settled wastewater More commonly called returned activated sludge

return sludge I Settled activated sludge that is returned to mix with incoming raw or primary settled wastewater for purposes of inoculation 2 Biomass produced in the activated sludge

process that is recycled to the head of the process to promote more complete biological oxidation

reuse AppIication of appropriately treated wastewater to a constructive purpose reverse osmosis

An advanced method used in water and wastewater treatment which relies

upon a semipermeable membrane to separate the water from its impurities An external force is used to reverse the normal osmotic flow resulting in movement of the water from a solution of

higher solute concentration to one of lower concentration Sometimes called hyperfiltration revolving screen

A screen or rack in the form of a cylinder or a continuous belt which is

revolved mechanically The screenings are removed by water jets or automatic scrapers or manually right of access A well founded legal claim to approach enter on or be on the bank of a stream

or other body of water One who seeks the right to use or divert water in or from the stream or lake must have the right of access before the right may be lawfully exercised rightofway A right of passage over another person sland riprap

Broken stone or boulders placed compactly or irregularly on dams levees dikes or

similar embankments for protection of earth surfaces against the action of waves or currents rising sludge

Rising sludge occurs in the secondary clarifiers of activated sludge plants when

the sludge settles to the bottom of the clarifier is compacted and then starts to rise to the surface

rodding A method used to clean small sewers Sections of flexible rods are screwed together and inserted into the sewer to make up the length of rod necessary to remove obstructions rodding machine

A device which imparts axial and horizontal movement to flexible rods for

the purpose of cleaning small sewers rotating biological contactor RBC A device for wastewater treatment which is composed of

large closely spaced plastic discs that are rotated about a horizontal shaft The discs alternately move through the wastewater and the air and develop a biological growth on their surfaces roughing filter A trickling filter used to remove an initial portion of the soluble BOD usually about 50

but not to effect complete removal

roughness A measure of the resistance to fluid flow of a channel pipe or other conduit as a result of its fabrication scale formation biological growth or other causes roughness coefficient A factor in the Chezy Darey Weisbach Hazen Williams Kutter Manning and other formulas for computing the average velocity of flow of water in a conduit or

channel which represents the effect of roughness of the confining material on the energy losses in the flowing water

safety valve A valve that automatically opens when prescribed conditions usually of pressure are exceeded In a pipeline or other closed receptacle containing liquids or gases and prevents such conditions from being exceeded and causing damage salinity

1 The relative concentration of dissolved salts usually sodium chloride in a given

water It is often expressed as mg 1 chlorine 2 A measure of the concentration of dissolved mineral substances in water

Salmonella

A genus of aerobic rodshaped usually motile bacterial that are pathogenic for

man and other warmblooded animals

sampler A device used with or without flow measurement to obtain a portion of water or waste

for analytical purposes May be designed for taking single sample grab composite sample continuous sample periodic sample

sand filter A bed of sand through which water is passed to remove fine suspended particles Very common in water treatment plants also used in tertiary wastewater treatment plants and sludge drying beds

sand trap A device often a simple enlargement in cross sectional area placed in a conduit to remove sand or silt carried by the water It usually includes means for ejecting the settled material

sanitary collection system

The sewer network used for the collection and conveyance of

municipal wastewater

sanitary engineer

A professional trained in the design of water and wastewater treatment

facilities An environmental engineer

sanitary sewage

Home wastewater that contains human wastes the major fraction of

municipal wastewater

sanitary sewer A sewer that caries liquid and waterborne wastes from residences commercial buildings industrial plants and institutions together with minor quantities of ground storm and surface waters that are not admitted intentionally

sanitary survey

1 An investigation of any condition that may affect public health 2 A

study of conditions related to the collection treatment and disposal of liquid solid or airbome

wastes to determine their potential environmental hazard 3 A study of the effect of wastewater discharges on sources of water supply on bathing or other recreational waters on shellfish culture and other related environments

sanitary wastewater 1 Domestic wastewater with storm and surface water excluded 2 Wastewater discharging from the sanitary conveniences of dwellings including apartment houses and hotels office buildings industrial plants or institutions 3 The water supply of a community after it has been used and discharged into a sewer

sanitation

A general program of environmental health designed to provide a safe source and

safe distribution of potable water and proper collection of wastewater

scouring velocity The minimum velocity necessary to dislodge stranded material from the boundary of a waterway conduit or pipeline by a fluid in motion screen

1 A device with openings generally of uniform size used to retain or remove

suspended or floating solids in flowing water or wastewater and to prevent them from entering an intake or passing a given point in a conduit The screening element may consist of parallel

bars rods wires grating wire mesh or perforated plate and the openings may be of any shape although they are usually circular or rectangular 2 A device used to segregate granular material such as sand crushed rock and soil into various sizes

screening A pretreatment process to remove large suspended or floating solids from raw sewage or water to prevent subsequent plugging of pipes or damage to pumps screenings 1 Material removed front liquids by screens 2 Broken rock including the dust of a size that will pass through a given screen depending on the character of the stone scum

1 The extraneous or foreign matter which rises to the surface of a liquid and forms a

layer or film there 2 A residue deposited on a container or channel at the water surface 3 A mass ofsolid matter that floats on the surface

scum baffle A vertical baffle dipping below the surface of wastewater in a tank to prevent the passage of floating matter Also called scum board scum board A scum baffle

scum chamber

Space provided in a sludge digestion tank for accumulated scum rising from

the digestion unit

scum collector

A mechanical device for skimming and removing scum from the surface of

settling tanks

scum removal

Separation of floating grease and oil from wastewater usually during

pretreatment or primary treatment

sealing

Elimination of leakage of groundwater into an existing sewer line frequently by

pressure grouting

secondary effluent

1 The liquid portion of wastewater leaving secondary treatment 2 An

effluent that contains not more than 30 mgl1 each ofBOPS and suspended solids secondary settling tank A settling tank following secondary treatmentdesigned to remove by gravity part of the suspended matter Also called secondary clarifiers secondary treatment 1 Generally a level of treatment that produces removal efficiencies for

BOP and SS of85 2 Sometimes used interchangeably with concept of biological wastewater treatment particularly the activated sludge process Commonly applied to treatment that consists chiefly of clarification followed by a biological process with separate sludge collection and handling

secondary wastewater treatment

Wastewater treatment processes usually consisting of

primary treatment and biological oxidation using activated sludge or trickling filtration followed by clarification Usually interpreted as the attainment of at least 85 percent removal or secondary effluent concentration of Tess than 30 mg 1 of both BOPS and suspended solids on a monthly average basis

secondstage biochemical oxygen demand

That part of the oxygen demand associated with

the biochemical oxidation of nitrogenous material As the term implies the oxidation of the nitrogenous materials usually does not start until a portion o the carbonaceous material has been oxidized during the first stage

sediment

1 Solid material settled from suspension in a liquid 2 Mineral or organic solid

material that is being transported or has been moved from its site of origin by air water or ice and has come to rest on the earth s surface either above or below sea level 3 Inorganic or organic particles originating from weathering chemical precipitation or biological activity 4 Any solid phase settling out of a liquid phase as for example deposits in rivers and lakes sludge in clarifiers

sedimentation

1 The process of subsidence and decomposition of suspended matter carried

by water wastewater or other liquids by gravity It is usually accomplished by reducing the

velocity of the liquid below the point at which it can transport the suspended material Also called settling May be enhanced by coagulation and flocculation 2 In geology sedimentation consists of five fundamental processes weathering erosion transportation deposition and diagnosis or consolidation into rock 3 Solid liquid separation resulting from the application of an external force usually settling in a clarifier under the force of gravity It can be variously classed as discrete flocculent hindered and zone sedimentation

sedimentation basin

A basin or tank in which water or wastewater containing settleable solids

is retained to remove by gravity a part of the suspended matter Also called sedimentation tank settling basin settling tank

seepage 1 Percolation of water through the lithosphere Definitive meaning usually is described by an adjective such as influent effluent 2 The slow movement of water through small cracks pores interstices of a material into or out of a body of surface or subsurface water

3 The loss of water by infiltration from a canal reservoir or other body of water or from a field It is generally expressed as flow volume per unit time During he process of priming such loss is called absorption loss

self cleansing velocity The minimum velocity in sewers necessary to keep solids in suspension thus preventing their deposition and subsequent nuisance from stoppages and odors of decomposition

self monitoring

Any measuring and analyzing activities carried out by a permitter in

accordance with permit requirements separate sewer A sewer intended to receive only wastewater or storm water or surface water separate sewer system

A sewer system carrying sanitary wastewater and other water carried

wastes from residences commercial buildings industrial plants and institutions together with minor quantities of ground storm and surface waters that are not intentionally admitted

separate sludge digestion tank A tank in which sludge is placed to permit digestion to occur after its removal from wastewater flow Usually a structure completely separated from the flowing through structures

septage The sludge produced in individual on site wastewater disposal systems such as septic tanks and cesspools septic 1 Anaerobic 2 Putrid rotten foul smelling anaerobic septicity A condition produced by growth of anaerobic organisms

septic sludge

Sludge from a septic tank or partially digested sludge from an Imhoff tank or

sludge digestion tank

septic tank An underground vessel for treating wastewater from a single dwelling or building by a combination of settling and anaerobic digestion Effluent is usually disposed of by leaching Settled solids are pumped out periodically and hauled to a treatment facility for disposal septic wastewater Wastewater undergoing anaerobic decomposition service connection

A pipeline with its appurtenances which branches off or connects a water

or sewer main with premises

settleable floatable solids 1 That matter in wastewater which will not stay in suspension during a preselected settling period such as one hour but settles to the bottom floats to the top 2 In the Imhoff cone test the volume of matter that settles to the bottom of the cone in one

hour 3 Suspended solids that can be removed by conventional sedimentation

settled wastewater Wastewater from which most of the settleable solids have been removed by sedimentation Also called clarified wastewater

settling

The process of subsidence and deposition of suspended matter carried by water

wastewater or other liquids by gravity It is usually accomplished by reducing the velocity of the liquid below the point at which it can transport the suspended material Also called sedimentation

settling solids

Solids that settle in sedimentation tanks or sedimentation chambers and other

such tanks that are constricted for the purpose of removing this fraction of suspended solids settling tank A basin or tank in which water or wastewater containing settleable solids is retained to remove by gravity a part of the suspended matter Also called sedimentation basin sedimentation tank settling basin

settling time

The time necessary for the removal by gravitational settling aggregation or

precipitation of suspended or colloidal substances

sewage Household and commercial wastewater that contains human waste Distinguished from industrial wastewater

sewage charge A service charge made for providing wastewater collection and or treatment service A specific charge in contrast to an ad valorem tax

sewage gas 1 Gas resulting from the decomposition of organic matter in wastewater 2 Gas produced during the digestion of sludge sewage rate A charge or a schedule of charges for the collection or the collection and treatment of wastewater to users who are connected to the system It may be based on water

consumption wastewater flow strength of wastewater number and types of plumbing fixtures or some combination of these

sewage treatment plant STP

The central facility of wastewater treatment facilities which

contains all treatment processes exclusive of collection systems

sewage works All inclusive term for wastewater collection Dumping treatment and disposal facilities Term declining in use

sewer A pipe of conduit that carries wastewater or drainage water

sewerage A complete system of piping pumps basins tanks unit processes and appurtenances for the collection transporting treating and discharging ofwastewater Term declining in use sewer appurtenances Structures devices and appliances other than pipe or conduit which are integral parts of a sewer system for example manholes pipe encasement flap valves sewer ball A pneumatically inflated rubber or plastic ball used to clean small and medium sized sewers by partially blocking the sewer and inducing the backedup water to flow around the hall at high velocity so that it flushes away many deposits

sewer district 1 An organization created and operating under statute for the purpose of financing constructing and operating a wastewater system 2 The land or area within the

boundaries of a sewer district as delimited in the organizing statute It may embrace parts of one or more political subdivision sewer gas

A gas mixture of variable composition produced by anaerobic decomposition of

organic matter in sewers and manholes It contains high percentages of carbon dioxide and

varying amounts of methane hydrogen and hydrogen sulfide and maybe both dangerous to inhale and explosive sewer manhole A shaft or chamber providing access from the surface of

ground to a sewer

sewer outfall The outlet or structure through which wastewater is finally discharged sewer outlet The point of final discharge of wastewater or treatment plant effluent

sewer rod

A hard wood stick or light metal rod three to four feet long with a coupling on each

end Rods are joined and pushed into a sewer to dislodge obstructions sewer service charges

Monetary rates used by municipalities sanitary districts and authorities

for obtaining the revenue to construct operate and maintain wastewater systems and treatment facilities

sewer system

Collectively all of the property involved in the operation of a sewer utility It

includes land wastewater lines and appurtenances pumping stations treatment works and

general property Occasionally referred to as a sewerage system singlestage digestion Digestion limited to a single tank for the entire digestion period skimming 1 The process of diverting water from the surface of a stream or conduit by means of a shallow overflow to avoid diversion of sand silt or other debris or material carried as

bottom Load 2 The process of diverting water from any elevation in a reservoir by means of outlets at different elevations or by any other skinning device in order to obtain the most

palatable drinking water 3 The process of removing floating grease or scum from the surface of wastewater in a tank

skimmings Grease solids liquids and scum skimmed from wastewater settling tanks sludge

1 The accumulated solids separated from liquids such as water or wastewater during

processing 2 Organic deposits on bottom of streams or other bodies ofwater 3 The removed material resulting from chemical treatment coagulation flocculation sedimentation flotation andor biological oxidation of water or wastewater 4 Any solid material containing large amounts of entrained water collected during water or wastewater treatment

sludge age The average residence time of suspended solids in a biological waste treatment system equal to the total weight of suspended solids in the system divided by the total weight of suspended solids leaving the system per unit of time usually per day

sludge bank

Accumulated deposits of solids of wastewater or organic origin on the bottom

banks edges or shores of waterways or open water

sludge bed An area comprising natural or artificial layers of porous material on which digested wastewater sludge is dried by drainage and evaporation A sludge bed may be open to the atmosphere or covered usually with a greenhouse type superstructure Also called sludge drying bed

sludge cake

Wastewater solids that have been sufficiently dewatered to form a semisolid

mass

sludge collector A mechanical device for scraping the sludge on the bottom of a settling tank to a sump from which it can be drawn

sludge concentration

Any process of reducing the water content of sludge which leaves the

sludge in a fluid condition

sludge conditioning

Treatment of liquid sludge before dewatering to facilitate dewatering and

enhance drainability usually by the addition of chemicals

sludge density index A measure of the degree of compaction of a sludge after settling in a graduated container expressed as g The sludge volume index SVI is the reciprocal of the sludge density index SDI

sludge digestion The process by which organic or volatile matter in sludge is gasified liquified mineralized or converted into more stable organic matter through the activities of either anaerobic or aerobic organisms

sludge digestion tank A tank in which sludge is placed for the purpose of permitting digestion to occur

sludge drying The process of removing a large percentage of moisture from sludge by drainage or evaporated by any method

sludge filter

A device in which wet sludge usually conditioned by a coagulant is partly

dewatered by means of vacuum or pressure

sludge index Properly called sludge volume index SVT It is the volume in milliliters occupied by 1 g of activated sludge after settling of the aerated liquid for 30 mm sludge lagoon

A basin used for the storage digestion or dewatering of sludge

sludge pressing The process of dewatering sludge by subjecting it to pressure usually within a cloth fabric through which the water passes and in which the solids are retained sludge seeding In biological treatment of wastewater and associated sludges the inoculation of

the unit process with biologically active sludge resulting in acceleration of the initial stage of the process

sludge treatment The processing of wastewater sludges to render them innocuous This may be done by aerobic or anaerobic digestion followed by drying on sand beds filtering and incineration filtering and drying or wet air oxidation sludge utilization

The use of wastewater sludges as soil builders and fertilizer admixtures

Sludges produced by aerobic and anaerobic digestion and activated sludge are used for these purposes

sodium hypochlorite

A water solution of sodium hydroxide and chlorine in which sodium

hypochlorite is the essential ingredient soil absorption capacity In subsurface effluent disposal the ability of the soil to absorb water

solid liquid separation Any process for removing suspended solids from water or wastewater solids

In water and wastewater treatment any dissolved suspended or volatile substance

contained or removed from water or wastewater

solids disposal

Any process for ultimate disposal of solid wastes or sludges by incineration

landfilling soil conditioning or other means

special assessment

A direct tax levy assessed against property to pay for improvements which

ordinarily are a direct benefit to the property itself

spray aerator An aerator consisting of a pressure nozzle through which water is propelled into the air in a fine spray Also called nozzle aerator stabilization basin

A natural or artificial structure specifically designed and used to retain a

biologically active waste to provide additional stabilization

stable effluent Treated wastewater that contains enough oxygen to satisfy its oxygen demand

stage aeration

Division of activated sludge treatment into stages with intermediate settling

stage digestion

The digestion of waste progressively in two more tanks arranged in series

tanks and return of sludge in each stage

usually divided into primary digestion with mixed contents and secondary digestion where quiescent conditions prevail and supernatant liquor is collected

stage trickling filter A series of trickling filters through which wastewater passes successively

with or without intermediate sedimentation

stale wastewater Wastewater containing little or no oxygen but as yet free from putrefieation standardrate filter A type of trickling filter in which both hydraulic and organic loadings are relatively low usually built to operate without recycling orrecirculation of wastewater

static head 1 The total head without reduction for velocity head or losses for example the difference in elevation of headwater and tail water of a power plant 2 The vertical distance

between the free level of the source of supply and the point of free discharge or the level of the free surface

sterilized wastewater An effluent from a wastewater treatment plant in which all microorganisms have been destroyed by sterilization

storm wastewater 1 That portion of liquid resulting from precipitation runoff flowing in combined sewers during or after a period of rainfall 2 Water resulting from precipitation runoff carried in a storm drain

discharg

A sewer into which the wastewater from two or more lateral sewers is an which subsequently discharges into a main a trunk or other collector

subsiding basin

A tank or basin in which water wastewater or other liquid containing

settleable solids is retained for a sufficient time and in which the velocity of flow is sufficiently low to remove by gravity a part of the suspended matter subsurface filtration

A wastewater treatment process in which a subsurface filter is used

subsurface wastewater disposal

The process of wastewater treatment and disposal in which

wastewater or effluent is applied to land by distribution beneath the surface through open jointed pipes or drains

superchlorination

Chlorination with doses that are deliberately selected to produce free or

combined residuals so large as to require dechiorination surcharge

1 The height of wastewater in a sewer manhole above the crown of the sewer

when the sewer is flowing completely full 2 Loads on a system beyond those normally

anticipated 3 An extra monetary charge imposed especially on flows into a wastewater collection system when set quantity or quality limits are exceeded surcharged manhole

A manhole that is receiving a flow in excess of that which can be

transported by the sewer line

surface aeration The absorption of air through the surface of a liquid surface microlayer

A thin measurable layer which can form on the surface of water bodies

consisting of natural and man made materials This Layer can concentrate certain pollutants to levels much higher than those formed in the water

SWRCB State Water Resources Control Board agency with overall responsibility for protecting water quality and administering the Clean Water Grant Program in the State of California through delegation agreements with EPA

tank A structure or container for containing water or wastewater for such purposes as aeration

disinfection equalization holding sedimentation treatment or for mixing dilution feeding or other handling of chemical additives

tank treatment The detention of wastewater in tanks either quiescent or with continuous flow TDS

Total dissolved solids

terminal manhole The first manhole at the upper end of a branch sewer line

terminal settling velocity

The maximum rate of sedimentation of a suspended particle that is

not hindered in any way

tertiary effluent The liquid portion of wastewater leaving tertiary treatment

tertiary treatment

The treatment of wastewater beyond the secondary or biological stage

Terms normally implies the removal ofnutrients such as phosphorus and nitrogen and of a high percentage of suspended solids Term now being replaced by preferable term advanced waste treatment

thickeners

Any process equipment or process after gravity sedimentation which increases the

concentration of solids in sludges with or without the use of chemical flocculants

threshold odor

The minimum odor of the water sample that can just be detected after

successive dilutions with odorless water Also called odor threshold

file field

A system of openjointed tile usually laid on a rock fill used for dispersing

wastewater effluents into the ground

tile wastewaterdisposal lines Lines of unglazed openjoint tile placed beneath the ground surface through which wastewater is dispersed by subsurface disposal

total dissolved solids TDS The sum of all dissolved solids volatile and nonvolatile in water or wastewater

total organic carbon TOC The amount of carbon bound in organic compounds in a sample

Because all organic compounds have carbon as the common element total organic carbon measurements provide a fundamental means of accessing the degree of organic pollution

total solids The sum ofdissolved and suspended solid constituents in water or wastewater toxic

Poisonous

toxic wastes

Wastes which when they come in contact with a biological entity cause an

adverse response

trap

1 A device used to prevent a material flowing or carried through a conduit from

reversing its direction of flow or movement or from passing a given point 2 A device to prevent the escape ofair from sewers through a plumbing fixture or catch basin

trash Debris that may be removed from reservoirs combined sewers and storm sewers by coarse racks trash rack A grid or screen placed across a waterway to catch flowing debris

trash screen A screen installed or constructed in a waterway to collect and prevent the passage oftrash treated sewage Wastewater that has received partial or complete treatment

trunk sewer A sewer that receives many tributary branches and serves a large territory turbidity 1 A condition in water or wastewater caused by the presence of suspended matter resulting in the scattering and absorption of light 2 Any suspended solids imparting a visible

haze or cloudiness to water which can be removed by filtration 3 An analytical quantity usually reported in turbidity units determined by measurements of light scattering

twostage digestion The biological decomposition of organic matter in sludge followed by solids liquid separation of the digested sludge Twostage digestion used two compartments or two tanks to separate the violent initial digestion period from the slower final period to enhance

both the digestion and the solid liquid separation after digestion

undigested sludge

Settled sludge promptly removed from sedimentation tanks before

decomposition has much advanced Also called raw sludge

upflow clarifier A treatment unit in which liquid containing suspended solids is passed upward through a blanket of settling sludge mixing flocculation and solids removal are all

accomplished in the same unit

vacuum filter 1 A filter used to accomplish sludge dewatering and consisting of a cylindrical

drum mounted on a horizontal axis covered with filter media and revolving partially submerged in a dilute sludge mixture A vacuum is maintained under the media for the larger part of a revolution to extract moisture The dewatered cake formed is scraped off mechanically for disposal 2 A diatomaceous earth water filter open to the atmosphere and on the inlet side of a

pump

vacuum filtration A usually continuous filtration operation that is generally accomplished on a rotating cylindrical drum As the drum rotates part of its circumference is subject to an internal vacuum that draws sludge to the filter medium and removes water for subsequent treatment The

dewatcred sludge cake is released by a scraper

value engineering VF

A specialized cost control technique based on a systematic and

creative approach which identified and focuses on unnecessarily high cost in a project in order to arrive at a cost saving without sacrificing the reliability or efficiency of the project Value engineering is required for all Step 2 grant applications having a projected total Step 3 grant eligible construction cost of 10 million or more excluding the cost of interceptors and collector sewers for all construction grant projects certified by the State on or after October 26 1976

valve 1 A device installed in a pipeline to control the magnitude and direction of the flow it

consists essentially of a shell and a disk or plug fitted to the shell 2 In a pump a waterway

passage through which is controlled by a mechanism

vapor 1 The gaseous form of any substance 2 A visible condensation such as fog mist or steam suspended in air ventilated manhole cover A manhole cover with openings in it for ventilation

video inspection The inspection of inaccessible or hazardous locations using closedcircuit

television usually applied to trunkmounted semiportable equipment used to inspect the inside

ofburied sewers Synonymous with television inspection

vitrified clay pipe A pipe made of clay and burned in a kiln with surfaces glazed or unglazed volatile acids Fatty acids containing six or less carbon atoms which are soluble in water and

which can be steam distilled at atmospheric pressure They have pungent odors and are often

produced during anaerobic decomposition

wash water Water used to wash filter beds in a rapid sand filter

waste 1 Something that Is superfluous or rejected something that can no longer be used for

its original purpose 2 Any solid liquid or gaseous emission that results from human activity 37

waste activated sludge Solids removed from the activated sludge process to prevent an excessive build up in the system waste disposal plant 1 A plant equipped for treatment and disposal of waste 2 An anof devices and structures for treating wastewater industrial wastes and sludge waste sludge Biological sludge that is drawn offto be conditioned for ultimate disposal waste treatment 1 A series of chemical physical or biological processes to remove dissolved

and suspended solids from wastewater before discharge 2 Any process to which wastewater or

industrial waste is subjected to make it suitable for subsequent use or acceptable for discharge to

the environment 3 In a broader sense encompasses the treatment and disposal of solid waste as well as wastewater wastewater The spent or used water of a community or industry which contains dissolved and suspended matter

wastewater charge

A service charge made for providing wastewater collection and or

treatment service A specific charge in contrast to an ad valorem tax

wastewater collection system

The sewer and pumping system used for the collection and

conveyance ofdomestic commercial and industrial wastewater

wastewater composition

1 The concentrations of the various solid liquid and gaseous

constituents of wastewater 2 The chemical biological and physical characteristics of the solid and liquid constituents of wastewater and their relationships

wastewater condition An expression defining the physical and biological state of waste liquid as between freshness and staleness or as between aerobic and anaerobic

wastewater decomposition Transformations of organic or inorganic materials contained in

wastewater through chemical or biological processes

wastewater disposal The act of disposing of wastewater by any method Not synonymous with wastewater treatment Common methods and instruments of disposal arc dispersion dilution broad irrigation privy cesspool

wastewater facilities The structures equipment and processes required to collect convey and treat domestic and industrial wastes and dispose of the effluent and sludge

wastewater lagoon An impoundment into which wastewater is discharged at a rate low enough

to permit oxidation to occur so that no substantial nuisance develops

wastewater management The collection and treatment of wastewater including such ancillary

matters as administration and financing engineering planning and design operation and maintenance and monitoring and evaluation of overall performance 38

wastewater outfall The outlet or structure through which wastewater is finally discharged wastewater reclamation Processing of wastewater for reuse

wastewater reuse The direct or indirect use of treatment plant effluent for municipal industrial agricultural recreational or water recharge applications wastewater treatment

Any process to which wastewater is subjected in order to remove or

alter its objectional constituents and thus render it less offensive or hazardous to human health and the environment

wastewater treatment plant

1 An arrangement of devices and structures for treating

wastewater industrial wastes and sludge Sometimes used as synonymous with waste treatment plant sewage treatment plant or wastewater treatment works 2 A water pollution control

plant 3 A facility engineered and constructed to remove pollutants from a predominantly liquid medium Often abbreviated as WWTP

water resources Water In various forms such as groundwater surface water rain snow ice or clouds recycled water that is potentially useful for some purpose WWTP

Wastewater treatment plant

Y connection 1 A pipe fining with three branches positioned in one plane in the pattern of the letter Y 2 More generally any junction of three pipes or open channels forming roughly in plan the letter Y

zero discharge

1 Complete recycling of water 2 Discharge of essentially pure water 3

Discharge of a treated effluent containing no substance at a concentration higher than that found normally in the local environment