HABITAT OS asier eguilaz
URBAN WATER SELF-SUFFICIENCY
FROM THE BUILDING TO THE CITY
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HABITAT OS URBAN WATER SELF-SUFFICIENCY, FROM THE BLOCK TO THE CITY
INDEX INDEX CHRONOGRAPHY
2 3-6
STATE OF THE ART WATER NEEDS TIPS FOR SAVING WATER WATER-EFFICIENT FIXTURES AND EQUIPMENT WATER RESOURCES RECYCLING WATER GREY WATER BLACK WATER
7 - 18 7-8 9 - 10 11 - 12 13 14 - 20
PROPOSAL DIAGRAMS
21 - 22
REFERENCES
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I would like to express my appreciation to Ferrán Sanchís, from BCNecología, for his continuous advices during the course HabitatOS. 2
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CHRONOGRAPHY Water supply and sanitation has been a primary logistical challenge since the dawn of civilization. Major human settlements could initially develop only where fresh surface water was plentiful, such as near rivers or natural springs. Throughout history people have devised systems to make getting water into their communities and households, and disposing wastewater more convenient.
6500 BC. During the Neolithic, humans dug the first permanent water wells, from where vessels could be filled and carried by hand. The size of human settlements was largely dependent on nearby available water. Pit latrines and chamber pots were initially the only alternative to open defecation. 4500 BC. Mesopotamia. First clay sewer pipes (Temple of Bel at Nippur and at Eshnunna, Babylonia). 2000 BC. Ancient Greek civilization, the first civilization to use underground clay pipes for sanitation and water supply. Well-organized water system for bringing in clean water, taking out waste water and storm sewage canals for overflow when there was heavy rain. First flush toilet, stone sewers that were periodically flushed with clean water. First heating systems, an indoor plumbing system, used for pressurized showers. 600 BC. The Roman Empire had indoor plumbing, meaning a system of aqueducts and pipes that terminated in homes and at public wells and fountains for people to use. Cloaca Maxima, disgorged into the Tiber.Public latrines were built over the Cloaca Maxima. 300 BC. Rome built its first aqueducts, powered entirely by gravity, and carried water over extremely large distances. They were applied specifically to supply water to the big cities and industrial areas of the Roman Empire. Most of the aqueducts were underground structures, to protect them in times of was and to prevent pollution. Together, they supplied Rome with over one million cubic meters of water on a daily basis. 212 BC. Archimedes invented the water screw. It is a large screw inside a hollow pipe that pumps up water to higher land. Originally, it was applied to irrigate cropland and to lift water from mines and ship bilges. 500 - 1500 AD. These centuries are known as the Dark Ages, because of a lack of scientific innovations and experiments. In medieval European cities, small natural waterways used for carrying off wastewater 3
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were eventually covered over and functioned as sewers. Open drains, or gutters, for waste water run-off ran along the center of some streets. 1370 AD. The first closed sewer constructed in Paris (Monmartre Street), designed by Hugues Aubird. The original purpose was to hold back the stench coming from the odorous waste water. Most cities did not have a functioning sewer system before the Industrial era, relying instead on nearby rivers or occasional rain showers to wash away the sewage from the streets. 1535 AD, (water treatment). London. There were efforts to stop polluting the River Thames in London. An Act passed that was to prohibit the dumping of excrement into the river. Leading up to the Industrial Revolution the River Thames was identified as being thick and black due to sewage. 1596 AD. Sir John Harington invented a flush toilet as a device for Queen Elizabeth I that released wastes into cesspools. After the adoption of gunpowder, municipal outhouses became an important source of raw material for the making of saltpeter in European countries. In London, the contents of the city’s outhouses were collected every night by commissioned wagons and delivered to the nitrite beds where it was sown into the special soil beds to produce earth rich in mineral nitrates. The nitrate rich-earth is then further processed to produce saltpeter, or potassium nitrate, an important ingredient in black powder. 1609AD, (water supply). From Hertfordshire to London. The construction of the New River to bring fresh water by Hugh Myddleton. 1627 AD, (water treatment). Sir Francis Bacon started experimenting with seawater desalination, by passing the flow through a sand filter. (Did not work)(Sand Filter). 1676 AD, (water treatment). Antonie van Leeuwenhoek and Robert Hooke (founders of microscopy), first time to observe water micro organisms. 1700 AD, (water treatment). First water filters for domestic application applied. Were made of wool, sponge and charcoal. 4
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SEWAGE TREATMENT PLANTS: As pollution of water bodies became a concern, cities attempted to treat the sewage before discharge. Early techniques involved land application of sewage on agricultural land. In the late 19th century some cities began to add chemical treatment and sedimentation systems to their sewers. These public health interventions succeeded in drastically reducing the incidence of water-borne diseases among the urban population, and were an important cause in the increases of life expectancy experienced at the time. 1723 AD, (water supply). London. Due to a rapidly growing population, private water supply networks established. The Chelsea Waterworks Company created extensive ponds in the area bordering Chelsea and Pimlico using water from the tidal Thames. 1804 AD, (water treatment). Scontland. First actual municipal water treatment plant designed by Robert Thom. The water treatment is based on slow sand filtration, and horse and cart distributed water. 1806 AD, (water treatment). Paris operated a large water treatment plant. The water settled for 12 hours, before it was filtered. Filters consisted of sand and charcoal and where replaced every six hours. 1829 AD, (water treatment). London. James Simpson, for Chelsea Waterworks Company, designed the first treated public water supply (with sand filter). The installation provided filtered water for every resident of the area, and the network design was widely copied throughout the United Kingdom in the ensuing decades. 1845 AD. Rotherham. The first screw-down water tap (brass foundry ) was patented by Guest and Chrimes. 1854 AD, (water treatment). London. John Snow’s map ‘On the Mode of Communication of Cholera’ conclusively demonstrated the role of the water supply in spreading the cholera epidemic. 1855 AD, (water treatment). London. The Metropolis Water Act introduced the regulation of the water supply companies, including minimum standards of water quality for the first time (sand filters and chlorination). 1879 AD, (water treatment). William Soper used, for first time, chlorinated lime to treat the sewage produced by typhoid patients. 5
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1880 AD. The U-bend pipe was invented by Thomas Crapper. 1894 AD, (water treatment). Moritz Traube, investigator, formally proposed the addition of chloride of lime (calcium hypochlorite) to water to render it “germ-free.� 1890 AD, (sewage treatment plant). Worcester, Massachusetts (USA); started building large sand filters to protect public health. Instead of slow sand filtration, rapid sand filtration was now applied. Filter capacity was improved by cleaning it with powerful jet steam. Dr. Fuller found that rapid sand filtration worked much better when it was preceded by coagulation and sedimentation techniques. 1902 AD, (water treatment). The negative effects of the chlorine were discovered (much faster vaporization than water). In Belgium, an alternative was found: Calcium hypo chlorite and ferric chloride were mixed in a drinking water supply, resulting in both coagulation and disinfection. Additionally, people started installing home water filters and shower filters to prevent negative effects of chlorine in water. 1912 AD, (sewage treatment plant). Scientists at the University of Manchester discovered the sewage treatment process of activated sludge. 1914 AD, (water treatment). Drinking water standards were implemented for drinking water supplies in public traffic, based on coliform growth. It would take until the 1940s before drinking water standards applied to municipal drinking water. 1945, (water treatment). Grand Rapids, Michigan. First water flouration application, to decrease tooth decay. 1974 AD. Safe Drinking Water Act (SDWA) was formulated. The general principle in the developed world now was that every person had the right to safe drinking water. 2015 AD. The Sustainable Development Goals formulated in 2015 include targets on access to water supply and sanitation at a global level.
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STATE OF ART WATER NEEDS A building is self-sufficient in water when consuming the least possible amount of water, and is able to get the water it needs by itself, at the lowest possible cost, so that does not require connection to the mains water supply. First, you need to define the amount of water that each inhabitant needs on a daily basis. In general, domestic water-uses tend to change depending on the socioeconomic level and the range can be extremely wide. The typology of domestic consumption normally includes so-called interior-uses (bathroom, kitchen, cleaning, appliances, etc.) and exterior-uses (watering gardens, pools, ornamental and other uses, etc.). We will focus on the main water need that concerns to the interior of the building. So in general, according to Domene and Sauri (fundacionaquae.org), domestic consumption of households in densified urban typologies (apartment blocks) present a distribution that roughly correspond to the following pattern of consumption: 32,73 % 22,33 % 17,17 % 10,33 % 5,45 % 5,16 % 6,83 %
Shower and bath. Toilet. Sink. Washing maching. Dishwasher. Drinking and food preparation. Other.
According to Manuel GarcĂa PĂŠrez, from Urban Ecology of Barcelona; threshold-demand of water should be around 100 LPD in a developed country. In Barcelona, for example, each inhabitant makes use of 101,1 litres per day.
There is a big consumption that should be improved. On one hand, water consumption must be reduced through new technologies (recycled water) and a more efficient use of it. On the other hand, better habits must be added in our daily basis, adopting a amore conscious approach with the use of the water.
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www.aiguesdebarcelona.cat/
www.aiguesdebarcelona.cat/
Projected water scarcity in 2025 | www.fewresources.org/
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TIPS FOR SAVING WATER Better habits must be added in our daily basis, adopting a amore conscious approach with the use of the water.
pans may require more cooking water than necessary. 15. If you accidentally drop ice cubes, don’t throw them in the sink. Drop them in a house plant instead. 16. Collect the water you use while rinsing fruit and vegetables. Use it to water house plants. 17. When shopping for a new dishwasher, use the Consortium for Energy Efficiency website to compare water use between models.
Here are some tips.
KITCHEN
1. There are a number of ways to save water, and they all start with you. 2. When washing dishes by hand, don’t let the water run. Fill one basin with wash water and the other with rinse water. 3. Dishwashers typically use less water than washing dishes by hand. Now, Energy Star dishwashers save even more water and energy. 4. If your dishwasher is new, cut back on rinsing. Newer models clean more thoroughly than older ones. 5. Designate one glass for your drinking water each day, or refill a water bottle. This will cut down on the number of glasses to wash. 6. Soak pots and pans instead of letting the water run while you scrape them clean. 7. Use the garbage disposal sparingly. Instead, compost vegetable food waste and save gallons every time. 8. Wash your fruits and vegetables in a pan of water instead of running water from the tap. 9. Don’t use running water to thaw food. For water efficiency and food safety, defrost food in the refrigerator. 10. Install an instant water heater near your kitchen sink so you don’t have to run the water while it heats up. This also reduces energy costs. 11. Keep a pitcher of drinking water in the refrigerator instead of running the tap. This way, every drop goes down you and not the drain. 12. Reuse leftover water from cooked or steamed foods to start a nutritious soup, it’s one more way to get eight glasses of water a day. 13. Cook food in as little water as possible. This also helps it retain more nutrients. 14. Select the proper pan size for cooking. Large
LAUNDRY ROOM 18. When doing laundry, match the water level to the size of the load. 19. Washing dark clothes in cold water saves water and energy, and helps your clothes retain their color. 20. When shopping for a new washing machine, compare resource savings among Energy Star models. Some can save up to 20 gallons of water per load. 21. Have a plumber re-route your greywater to trees and plants rather than the sewer line. Check with your city and county for codes. 22. When buying a washer, check the Consortium for Energy Efficiency website to compare water use between models.
BATHROOM 23. If your shower fills a one-gallon bucket in less than 20 seconds, replace the showerhead with a WaterSense® labeled model. 24. Shorten your shower by a minute or two and you’ll save up to 150 gallons per month. 25. Time your shower to keep it under 5 minutes. You’ll save up to 1,000 gallons per month. 26. Toilet leaks can be silent! Be sure to test your toilet for leaks at least once a year. 27. Put food coloring in your toilet tank. If it seeps into the bowl without flushing, there’s a leak. Fix it and start saving gallons. 28. When running a bath, plug the bathtub befo9
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re turning on the water. Adjust the temperature as the tub fills. 29. Upgrade older toilets with water-saving WaterSense® labeled models. 30. If your toilet flapper doesn’t close properly after flushing, replace it. 31. Use a WaterSense® labeled showerhead. They’re inexpensive, easy to install, and can save you up to 750 gallons a month. 32. Turn off the water while you brush your teeth and save up to 4 gallons a minute. That’s up to 200 gallons a week for a family of four. 33. If your toilet was installed before 1992, purchasing a WaterSense® labeled toilet can reduce the amount of water used for each flush. 34. Consider buying a dual-flush toilet. It has two flush options: a half-flush for liquid waste and a full-flush for solid waste. 35. Plug the sink instead of running the water to rinse your razor and save up to 300 gallons a month. 36. Turn off the water while washing your hair and save up to 150 gallons a month. 37. When washing your hands, turn the water off while you lather. 38. Take 5-minute showers instead of baths. A full bathtub requires up to 70 gallons of water. 39. Install water-saving aerators on all of your faucets. 40. Drop tissues in the trash instead of flushing them and save water every time. 41. Look for WaterSense® labeled toilets, sink faucets, urinals and showerheads. 42. One drip every second adds up to five gallons per day! Check your faucets and showerheads for leaks. 43. While you wait for hot water, collect the running water and use it to water plants.
use the Home Water Audit Calculator to see where you can save water. 46. When the kids want to cool off, use the sprinkler in an area where your lawn needs it most. 47. Encourage your school system and local government to develop and promote water conservation among children and adults. 48. Play fun games while learning how to save water! 49. Monitor your water bill for unusually high use. Your bill and water meter are tools that can help you discover leaks. 50. Learn how to use your water meter to check for leaks. 51. Reward kids for the water-saving tips they follow. 52. Avoid recreational water toys that require a constant flow of water. 53. Grab a wrench and fix that leaky faucet. It’s simple, inexpensive, and you can save 140 gallons a week. 54. Hire a GreenPlumber® to help reduce your water, energy, and chemical use. 55. Be a leak detective! Check all hoses, connectors, and faucets regularly for leaks. 56. We’re more likely to notice leaky faucets indoors, but don’t forget to check outdoor faucets, pipes, and hoses. 57. See a leak you can’t fix? Tell a parent, teacher, employer, or property manager, or call a handyman. 58. At home or while staying in a hotel, reuse your towels. 59. Make suggestions to your employer or school about ways to save water and money. 60. Run your washer and dishwasher only when they are full. You can save up to 1,000 gallons a month. 61. See how your water use stacks up to others by calculating your daily water use.
GENERAL INDOOR 44. Teach children to turn off faucets tightly after each use. 45. Watch the Home Water Challenge video or 10
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WATER-EFFICIENT FIXTURES AND EQUIPMENT Reducing water use from fixtures and equipment is perhaps the easiest method to reduce total potable water use. It does not require extensive design solutions, just specifying certain products. Avoiding large fountains, pools, and other water features will also save water use. According to Water Efficiency Labelling and Standards (WELS) scheme, about 25 per cent of water savings will come from using more water-efficient showerheads, another 50 per cent from more efficient washing machines and over 20 per cent from water-efficient toilets. Fixtures that save water include low-flow shower heads, sinks with auto-shutoff mechanisms, and water-saving toilets and urinals. Equipment that saves water includes dishwashers, clothes washers, other commercial kitchen equipment such as sprayers and steam cookers, as well as industrial process equipment.
WATER–EFFICIENT FAUCETS AND FAUCET ACCESSORIES According to EPA (United States Environmental Protection Agency), WaterSense labeled faucets and faucet accessories (such as aerators) are high–performing, water–efficient fixtures that will help you reduce water use in your home and save money on water bills. WATER–EFFICIENT SHOWERHEADS Water–saving showerheads that earn the WaterSense label must demonstrate that they use no more than 2.0 gpm (instead of 2.5 gpm). The WaterSense label also ensures that these products provide a satisfactory shower that is equal to or better than conventional showerheads on the market. WATER–EFFICIENT TOILETS AND URINALS Recent advancements have allowed toilets to use 1.28 gallons per flush or less while still providing equal or superior performance. This is 20 percent less water than the current federal standard of 1.6 gallons per flush. PRE-RINSE SPRAY VALVES Pre-rinse spray valves can account for nearly one-third of the water used in the typical kitchen. EPA’s specification sets the maximum flow rate for WaterSense labeled pre–rinse spray valves at 1.28 gpm, or 20 percent less water than the federal standard, and includes spray force criteria and lifecycle testing to ensure performance in kitchens. LANDSCAPE IRRIGATION CONTROLLERS WaterSense labeled irrigation controllers, which act like a thermostat for your sprinkler system telling it when to turn on and off, use local weather and landscape conditions to tailor watering schedules to actual conditions on the site. Instead of irrigating using a controller with a clock and a preset schedule, 11
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Irrigation Controllers | www.rainbird.com/
Pre-Rinse Spray Valve | www.ecosmartinc.com/
Hansgrohe EcoSmart | www.roomh2o.co.uk/ 12
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WATER RESOURCES Water covers some 70% of the Earth’s surface. Approximately 97.2% of it is saline, just 2.8% fresh. Potable water is available in almost all populated areas of the Earth, although it may be expensive and the supply may not always be sustainable. Sources where water may be obtained include: • • • • • • •
Ground sources such as groundwater, springs, hyporheic zones and aquifers Precipitation which includes rain, hail, snow, fog, etc. Surface water such as rivers, streams, glaciers Biological sources such as plants. Desalinated seawater Water supply network Atmospheric water generator
For this scenario, we will focus on the water coming from the net, from the rain-water and from a well. Pipe water comes from a water supply system or water supply network. It is a system of engineered hydrologic and hydraulic components which provide water supply. Raw water (untreated) is collected from a surface water source (such as an intake on a lake or a river) or from a groundwater source (such as a water well drawing from an underground aquifer) within the watershed that provides the water resource. The raw water is transferred to the water purification facilities using uncovered aqueducts, covered tunnels or underground water pipes. Virtually all large systems must treat the water, consists of three steps: clarification, filtration and disinfection. A water well is an excavation or structure created in the ground by digging, driving, boring, or drilling to access groundwater in underground aquifers. The well water is drawn by a pump. This type of water is to be used, along with rainwater, to supply the needs of potable water suitable for human consumption. Therefore it should be treated and disinfected properly. Depending on the type of water available in a given location, and level and type of pollutants, the usual treatment of groundwater can be Level 1 (simple physical treatment + disinfection) or Level 2 (Normal physical treatment + chemical treatment + disinfection). Rainwater harvesting is the accumulation and deposition of rainwater for reuse on-site, rather than allowing it to run off. Generally, rain water has a good quality, since it only has been contaminated with local air pollutants in suspension, and the contaminants in the own covered where rain has fallen. Therefore, the usual type of treatment is very simple and, with simple procedures desinfección- is easily converted into drinking water. The best type of cover to collect rainwater is the roof garden, providing a first natural filtering in the general treatment system. The usual treatment of rainwater is Level 1 (simple physical treatment + disinfection).
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RECYCLED WATER In identifying alternative sources of water, the first consideration is what those sources will be used for. Potable water, which we can use for drinking, cooking, and bathing, must meet a high level of purity and safety. Nonpotable water is less pure but, when handled properly, it can be fine for landscape irrigation, toilet flushing and washing machines. Many alternative water sources are best suited to nonpotable uses, though some can be made potable with additional treatment. If we can provide separate plumbing in and around buildings for potable and nonpotable water, it opens up significant new options for water supply. Installing separate supply piping for landscape irrigation and cooling-tower makeup water is fairly easy, while installing separate nonpotable supply plumbing for toilet flushing, which requires dual piping throughout a building, is more difficult.
GREYWATER is all wastewater generated in households from streams without fecal contamination. Sources of greywater include: sinks, showers, baths or dish washers. It is generally safer to handle and easier to treat and reuse onsite for toilet flushing, landscape or crop irrigation, and other non-potable uses. The application of greywater reuse in urban water systems provides substantial benefits for both the water supply subsystem by reducing the demand for fresh clean water as well as the wastewater subsystems by reducing the amount of wastewater required to be conveyed and treated. Most greywater is easier to treat and recycle than blackwater (sewage), because of lower levels of contaminants. If collected using a separate plumbing system from blackwater, domestic greywater can be recycled directly within the home or garden and used either immediately or processed and stored. If stored, it must be used within a very short time or it will begin to putrefy due to the organic solids in the water. Recycled greywater of this kind is never safe to drink, but a number of treatment steps can be used to provide water for washing or flushing toilets. The treatment processes that can be used are in principle the same as those used for sewage treatment, except that they are usually installed on a smaller scale (decentralized level), often at household or building level: • Biological systems such as constructed wetlands or living walls and bioreactors or more compact systems such as membrane bioreactors which are a variation of the activated sludge process and is also used to treat sewage. • Mechanical systems (sand filtration, lava filter systems and systems based on chlorination or UV radiation). 14
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In constructed wetlands, the plants use contaminants of greywater, such as food particles, as nutrients in their growth. However, salt and soap residues can be toxic to microbial and plant life alike, but can be absorbed and degraded through constructed wetlands and aquatic plants such as sedges, rushes, and grasses.
WASTEWATER is any water that has been adversely affected in quality by anthropogenic influence. Sewage is a type of wastewater that comprises domestic wastewater and is therefore contaminated with feces or urine from people’s toilets and any other used. There are numerous processes that can be used to clean up wastewaters depending on the type and extent of contamination. Wastewater can be treated in wastewater treatment plants which include physical, chemical and biological treatment processes. Municipal wastewater is treated in sewage treatment plants. For municipal wastewater the use of septic tanks and other On-Site Sewage Facilities (OSSF) is widespread in some neighbours One type of aerobic treatment system is the activated sludge process, based on the maintenance and recirculation of a complex biomass composed of micro-organisms able to absorb and adsorb the organic matter carried in the wastewater. Anaerobic digester wastewater treatment processes can be used both on a large scale, and domestic use. Properly treated, wastewater can be used as irrigation and crop fertilizer, and to produce biogas.
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GREY WATER NATURAL RECYCLING PROPOSAL There is a need for a treatment of grey water or waste water close to the point of use. The use of artificial wetlands in waste trearment permit to benefit from natural processes which eliminate or reduce non desired substances from the water (creation of an active substrate; reduction of the contamination; very efficient elimination of carbon; nitrogen and phosphorous; possibility to eliminate even heavy metals by using processes of selective uptake and accumulation by plants (known as phytoremediation). However, there is a lack of space. Here is where a green wall comes up. BABYLON - BABYLON® GREEN WALL Babylon® is a living façade modular and flexible system of great beauty and impact which integrates lots of benefits in a new concept of urban landscape. The vertical gardens consist of draping walls and other surfaces achieving that the plants grow of ideal form without scarcely substratum. These vertical walls suppose a work of minimal maintenance that diminishes to a periodic review of the facilities and to the eventual prunings of the plants. The Babylon ® system is designed to achieve maximim safety against irrigation facilities failure. The substrate 14 cm thick, works as a water retainer to ensure the life plant for 15 days. The system allows the treatment and reuse of greywater. In urban areas, the generation of domestic wastewater and the need for watering gardens and green areas occur in the same environment. Vivers Ter with Asepma (www.asepma.com) has developed and patented a new technology with proven gray water treatment by biofiltration using the architectural element of the vegetable walls. (First of all, there is a need for eliminating of solids before entering the Babylon façade). Green Wall Babylon ® (Patent: U.S. 2008 01210) offers the possibility of regeneration greywater from shower and sink through the purification system in vertical gardening for different uses.
Babylon Green Wall | www.v-ter.com/ 16
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MECHANICAL GREY WATER RECYCLING Blackwater applies for any used water coming from showers, baths, basins or tap water. There have been many developments in this field, due to the scarcity of water in several estates around the world. It may be contaminated with a range of soluble and insoluble (particulate) substances like soaps, detergents, skin, saliva, dirt and lint. Each type of contaminant must be treated appropriately, whether it is detergent/surfactant, organic, microbial or particulate. There are several proposals about this issue. A company called Acuacell, for instance, claims that once the system is installed you’ll have instant access to a never-ending supply of recycled water for all your non-drinking needs. Designed with a multi-barrier approach, it combines a range of purifying processes to remove all those nasty contaminants and make your greywater ready to use again. The solution may vary, but in general, it is based on a simple modular solution for on-site greywater recycling. The system features a controlled, robust and comprehensive treatment process that combines physical, microbiological and oxidative treatments in one package. This is how it works, step by step, the mechanical solution proposed for greywater recycling: WATER COLLECTION. Water flows from throughout the property to a collection point where it is pumped into the system. This is where the treatment process starts. AEROBIC SCREENING. This process reduces insoluble material to a negligible residue. This residue is either discharged to the sewer or de-watered and compacted for disposal as solid waste. BIOLOGICAL TREATMENT. Air is diffused into the water to make ideal conditions for bacteria to consume impurities. A sustainable biomass concentration is maintained, which metabolises all the incoming waste. This means there’s negligible sludge and 99.9 per cent of the incoming water is re-used. ULTRAFILTRATION. Ultrafiltration occurs through a special membrane of microscopic pores that stop particles, bacteria and viruses from passing through. The membranes are cleaned by air scouring to make sure no wastewater is produced. ULTRAVIOLET DISINFECTION. As a precaution, ultraviolet lamps are included in all Aquacell blackwater systems to up the protection against pathogens. CHLORINATION. A chlorine residual is added to protect the water while in storage and the reticulation system. This is the only time any chemicals are used in the treatment process. TREATED WATER STORAGE. The result is safe water, kept in storage for future use in a variety of applications including surface irrigation, toilet flushing, washing machines and dishwashers.
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BLACKWATER RECYCLING Blackwater applies for any wastewater that is contaminated with water discharged from a toilet. There have been many developments in this field, due to the scarcity of water in several estates around the world. There are several proposals about this issue. A company called Acuacell, for instance, claims that once the system is installed you’ll have instant access to a never-ending supply of recycled water for all your non-drinking needs. The solution may vary, but in general, it is based on a simple modular solution for on-site blackwater recycling. The system features a controlled, robust and comprehensive treatment process that combines physical, microbiological and oxidative treatments in one package.
This is how it works, step by step, the mechanical solution proposed for blackwater recycling: WATER COLLECTION. Water flows from throughout the property to a collection point where it is pumped into the system. This is where the treatment process starts. AEROBIC SCREENING. This process reduces insoluble material to a negligible residue. This residue is either discharged to the sewer or de-watered and compacted for disposal as solid waste. BIOLOGICAL TREATMENT. Air is diffused into the water to make ideal conditions for bacteria to consume impurities. A sustainable biomass concentration is maintained, which metabolises all the incoming waste. This means there’s negligible sludge and 99.9 per cent of the incoming water is re-used. ULTRAFILTRATION. Ultrafiltration occurs through a special membrane of microscopic pores that stop particles, bacteria and viruses from passing through. The membranes are cleaned by air scouring to make sure no wastewater is produced. ULTRAVIOLET DISINFECTION. As a precaution, ultraviolet lamps are included in all Aquacell blackwater systems to up the protection against pathogens. TDS AND NUTRIENT REMOVAL. These technologies are employed for things like cooling tower re-use and discharge to sensitive environments. CHLORINATION. A chlorine residual is added to protect the water while in storage and the reticulation system. This is the only time any chemicals are used in the treatment process. TREATED WATER STORAGE. The result is safe water, kept in storage for immediate use in a variety of non-potable applications, including surface irrigation and toilet flushing.
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FROM GREYWATER TO TAPWATER Reclaimed water for drinking use? This is the case of Singapore, where NEWater is a pillar of its water sustainability strategy. NEWATER is high-grade reclaimed water produced from treated used water that is further purified using advanced membrane technologies and ultra-violet disinfection, making it ultra-clean and safe to drink. Test results from the two-year comprehensive physical, chemical and microbiological study showed that the quality of NEWater consistently exceeds the requirements stipulated in the USEPA and WHO guidelines. This would be the recycling process: STAGE 1 - MICROFILTRATION. The treated used water is passed through membranes to filter out and retained on the membrane surface suspended solids, colloidal particles, disease causing bacteria, some viruses and protozoan cysts. The filtered water that goes through the membrane contains only dissolved salts and organic molecules. STAGE 2 - REVERSE OSMOSIS. A semipermeable membrane is used; which has very small pores that only allow very small molecules like water molecules to pass through. Undesirable contaminants (such as bacteria, viruses, heavy metals, nitrate, chloride, sulphate, etc) cannot pass through the membrane. At the stage, the water is free from viruses, bacteria and contains negligible amount of salts and organic matters. STAGE 3 - UV DISINFECTION. The water is already of a high grade water quality. At this phase, the process acts as a further safety back-up to the RO. Ultraviolet or UV disinfection is used to ensure that all organisms are inactivated and the purity of the product water guaranteed. STAGE 4 - BEFORE STORING NEWATER IN TANKS, BALANCE THE PH. With the addition of some alkaline chemicals to restore the acid-alkali or pH balance, the NEWater is now ready to be piped off to its wide range of applications.
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HABITAT OS URBAN WATER SELF-SUFFICIENCY, FROM THE BLOCK TO THE CITY
Newater diagram | www.pub.gov.sg/
US recycling water for drink | www.pub.gov.sg/ 20
HABITAT OS URBAN WATER SELF-SUFFICIENCY, FROM THE BLOCK TO THE CITY
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SOME DATA SOURCE
ISSUE
TAP WATER
32,73 L Shower and bath Drinking and food preparation 5,16 L 17,17 L Sink
RECYCLED WATER
DAILY
Washing maching Dishwasher Toilet Other
YEARLY
1.193.550 L 625.975 L 187.975 L
55,00 L
2.007.500 L
10,33 L
412.450 L
5,45 L
197.000 L
22,33 L
813.950 L
6,83 L
219.000 L
45,00 L
1.642.500 L 4500 LPD SEWAGE
IRRIGATION
Recycled rest-water Rain water
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10 L
365.000 L
-L
256.000 L
10,00 L
621.000 L
HABITAT OS URBAN WATER SELF-SUFFICIENCY, FROM THE BLOCK TO THE CITY
BABYLON SYSTEM
RAIN WATER
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NET IRRIGATION WATER
GREY WATER
RECYCLING SYSTEM
BLACK WATER
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HABITAT OS URBAN WATER SELF-SUFFICIENCY, FROM THE BLOCK TO THE CITY
REFERENCES www.aiguesdebarcelona.cat/ www.allstarce.com/ www.recoverwater.com/ www.thegreenage.co.uk/tech/greywater-recycling/ www.aquacell.com.au/ www.dewater.com/ www.pub.gov.sg/watersupply/waterquality/newater www.bcnecologia.net/ Smart Cities. La transformaciรณn digital de ciudades, by PwC and IE Business School The self sufficient city, by Vicente Guallart Self-Sufficient City, by Actar Publishers Ecosystemic Urbanism, by Urban Ecology Agency of Barcelona
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