THE
GREAT
BOOK
OF
TO I L E T S
TABLE OF CONTENT 1. What is DEWATS?
p. 2
2. DEWATS and the environment
p. 3
3. How the DEWATS works
p. 4
4. Safety protocol
p. 9
5. Interaction between urine and plants
p. 11
6. Preliminary teaching plan
p.14
7. School garden
p.24
8. References
p.27
1
1. WHAT IS DEWATS?
Decentralized Wastewater Treatment System (DEWATS) is an approach for wastewater treatment that relies on natural process that combine physical principles with biological activities of microorganisms. In this system, the human waste and urine are collected in toilets that are purposefully made to separate them from each other, so that they can later be processed and used. An important aspect of the system is also the small distance between the point of origin and treatment of wastewater, allowing an easy reuse of treated water and avoiding costs of elaborate collection and pumping systems.
The general aims of the DEWATS include improvements development
of of
sanitation, the
economic
community
and
contributing to environmental health. In this booklet, we focus on the environmental
benefits of treating human waste. So, what are these benefits?
2
2. DEWATS AND THE ENVIRONMENT
Nutrients are essential for plant growth. The aim is to create a nutrient loop. That means,
Nutrient Cycling
that nutrients of harvested crops do not get lost, but wander back into the soil, where they can again be taken up by plants. This is
important to improve the food system.
Renewable Energy
DEWATS features the possibility to provide renewable energy source (e.g., biogas)
The
high
wastewaters
concentration has
of a
untreated polluting
effect. Wastewater treatment like DEWATS
Pollution Reduction
can decrease the pollution of open-water bodies, groundwater and soil, which lowers the pathogen load, the level of heavy metals and eutrophication.
Natural WasteTreatment Process
3
3. HOW DOE
SCHOOL
STORAGE TA N K S
D E WAT S
4
ES IT WORK?
LOCAL STORES, S PA S , H O T E L S
SCHOOL GARDEN
NURSERY
5
The urine separation toilets will be installed in school, where students will be able to learn how their urine can be transformed into a fertilizer. By making students use the
SCHOOL
toilets appropriately and teaching them the environmental benefits of this system, the project could also ultimately contribute to attenuating the existing taboo around human waste.
After being collected in the toilets, the urine is stored in tanks until it is transported to the DEWATS treatment center. Storing urine in tanks is not only helpful for
STORAGE TA N K S
transportation efficiency, but also proved to help remove pathogens from the urine if it is stored for long enough.
6
D E WAT S
Settler:
Primary
treatment.
A
mechanical
treatment
by
sedimentation and simultaneous sludge digestion (biological treatment). In this first step, most scum and sludge are retained. Anaerobic Baffled Reactor: suspended and dissolved solids, that have not been removed in the first step, undergo anaerobic degradation (without oxygen) in the secondary treatment. In this way, activated sludge settles down to the bottom of each chamber. Meanwhile, the influent wastewater wanders through sludge blankets, where anaerobic bacteria use pollutants in the wastewater for their metabolism. This
leads to a reduction of pathogens between 40-75 %. Anaerobic Filter: Here, the treatment of non-settleable and dissolved solids is happening. “Hungry” microorganisms dispend the organic matter within a short time. Wetlands: The main treatment mechanisms are biological conversion, filtration and chemical adsorption. Like this, a pathogen removal of over 95 % can be achieved. Polishing pond: Enables light penetration and oxygenation of the pretreated wastewater, with which water quality is improved further.
7
The fertilizer will be used in different plant nurseries
to
improve
soil
nutrient
availability, and thereby help grow flowers
NURSERY
and indigenous trees.
The flowers grown in the nurseries can
then
customers
be
such
restaurants,
LOCAL STORES, S PA S , H O T E L S
basically
sold
to as
tourist anyone
who
various hotels, place, desires
beautiful flowers!
Finally, the loop can be closed back in the schools! Indeed, we propose to create a plant and flower garden, which can be used by teachers to illustrate the benefits of using urine fertilizers. Visit chapter 7 for
more details on the school garden.
8
SCHOOL GARDEN
4. SAFETY PROTOCOL
1. SCHOOL To ensure the safety of the toilet users, the following points must be considered: before using, the toilet and the surrounding area need to be in a clean state. If this is not the case, the responsible person at the school must be contacted. Unprotected contact with residues of human waste must be avoided. After using the toilet, it must be left in clean state, ready for the next user. Further, washing hands is important to ensure hygienic safety.
2. TREATMENT During
urine
treatment
in
the
DEWATS,
substances that could make the fertilizer product harmful to the environment or human health are removed. These elements are pharmaceuticals, heavy metals and pathogens such as bacteria and viruses. Biological and physical treatments
provide a safe end product.
9
3. FERTILIZER The duration of mandatory fertilizer storage time must be assured. Further, contamination with unstored faeces and urine must be avoided. When bringing out the fertilizer, the right amount needs to be applied, according to the needs of the respective plant. Children should not get in contact with the fertilizer. Avoid contact of the fertilizer of face or skin by wearing protective clothes. Avoid using the fertilizer for crops grown for food.
10
5. INTERACTION BETWEEN URINE AND PLANTS?
Nutrient recycling for food production can improve land management, food security and rural livelihoods.
Human urine is an effective and valuable resource for plant fertilization. Historically its use in agriculture was broadly used but due to social norms and taboos the demand and use became lower. Urine is in fact a very affordable, efficient and low-risk fertilizer.
Low levels of pathogens and considerable amounts of nutrients are two main qualities of human urine as a potential plant fertilizer. The nutrient content is around 3 g/L of nitrogen, 0.3 g/L of phosphorous and 1.74 g/L of potassium. The nutrient content can vary with the diet with a higher nitrogen content in diets containing more meat compared to vegetarian diets. Urine can be very effective especially in supplying nitrogen for crop growth.
A
study
conducted
in
South-Africa
has demonstrated that the effectivity of urine fertilizers is independent from the soil type. In the research the two considered
soils
where
arable
soil in Kwadina Bakubo and arable land in KwaZulu-Natal.
11
IMPROVING SOIL FERTILITY
Low and declining soil fertility can be a major problem in agricultural land in sub-Saharan Africa.
Crop
rotation,
mixed
crops
(intercropping) with legumes (which are able to assimilate nitrogen from the air and store it in the
soil,
making
it
available
for
plants),
composting and crop residue management are some of the practised methods to improve soil fertility.
One of the
main limitations
for
agricultural production is the low amount of nutrients available.
Urine adds nutrients especially in low fertility soils, where phosphorus and nitrogen are at low rates. The improve in growth and increase in yield was kale,
observed spinach)
for
crop and
(bean, for
maize, foraging
(Ryegrass, Lolium perenne) production. The lowcost of human urine also brings economic benefits together with the use of this kind of fertilizers.
12
GROWING PROCESS OF A PLANT AND NUTRIENT UPTAKE Light, water, air, temperature and nutrient availability are the main factors influencing the growth and development of a plant. The unavailability or reduced amount of one or more elements can compromise the health and fertility of the plant and lead to a reduced plant quality and harvest. The nitrogen contained in urine can be a valuable resource to supply the plants with the required nutrient needs for agricultural production.
Nutrient availability is a major component for the health of the plant; a limited amount of nutrients in the soil affects the basic cellular processes. Nutrient deficiency can result in a decrease in productivity, fertility, strictly related to the physiological negative effects of lack of nutrient: reduced photosynthesis rate due to reduced chlorophyll, death of plant tissues and slow growth.
13
6. PRELIMINARY TEACHING PLAN –HUMAN ENVIRONMENT INTERACTION
DISCLAIMER This chapter includes a suggestion of a teaching plan, describing how to integrate general concepts of the newly installed decentralised wastewater treatment system (DEWATS) in the broader scope of human environment interaction. This chapter, as the whole book, is directed towards teachers and should be considered as a guide rather than a concrete plan. Teachers may adapt the ideas presented in this chapter in their current teaching plan or may take their inspiration from elsewhere. The authors of this booklet believe in the power of teaching to ease the integration of the new sanitary facilities at their school as well as in the ability of the teachers to educate children from a young age on this complex topic.
INTEGRATION INTO CURRENT TEACHING PLAN We understand that elementary education in South Africa lasts seven years, divided in a foundation and intermediate phase, where the children start elementary school at six years old. Thus, we suggest that the age of the children and school subject should be considered when integrating the concepts of Human and Environment interaction. We propose to introduce first relevant terms in English (or another national language) or Home Language classes, so the children learn how to use these terms and words in the context of the topic. This will be the basis for further classes in the broader context of human environment interactions and the DEWATS.
14
ENGLISH AND HOME LANGUAGE Pupils should be introduced to the topics by learning some first English words with the translation in their home language (here isiZulu was used as an example). The single components of the broader topic, such as plants, environments and humans may be introduced before introducing the concept of the DEWATS. It would be great if the terms are embedded within a bigger story with a clear path and story line, where the children can easily follow and learn. It is important that the children know the English (or other national language) terms well also regarding the language of more advanced literature, where teachers might want to get some inspiration from.
15
BOTANY AND PLANTS Target audience:
Young pupils may be targeted, however more advanced topics may be taught to older pupils as well.
Basic learning goals: •
Introduction to some words concerning plants and botany in their native language and one national language
•
Draw simple (conceptual) plants and naming of the plant parts (such as on the image on the next page)
•
Introduction to common native/popular plants with the help of real plants
Advanced learning goals:
•
Ability to recognise and name specific plant varieties
•
Ability to recognise and name specific plant parts
•
Introduction to basic plant needs such as water, sun, soil, and nutrients
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Example of a simple drawing of a plant with parts of a flower
Examples of botany and plant terms, which could be introduced in Language classes to younger children.
isiZulu Imbali Impande/ingxabo Ukuhlukahluka/izinhlobonhlo bo iqabunga ukukhula Impova Imbewu/inhlwanyelo Isitshalo Umhlabathi Umquba/umanyolo Ingadi Khula/thuthuka Ukuchelela
English flower root variety leaf growth pollen seed plant soil fertilizer garden to grow to water
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ENVIRONMENT
Target audience:
Younger and older pupils. More advanced topics and words may be taught to older pupils exclusively. This part may be taught as part of English classes, natural science or life science.
Basic learning goals: •
Introduction to some words in the context of environment in their native language and one national language
•
Draw the introduced words/elements in a sketch and name them
•
Usage of the introduce word in a simple statement (native language)
Advanced learning goals (for older pupils): •
Write a text including the terms learned in this part.
•
Introducing the concept of nature conservation e.g. using local projects or initiatives
•
Introduction to important local insects and animals
18
Examples of terms focusing on the environment, which could be introduced in Language or science class.
isiZulu
English
izulu ihlathi umfula ukwakheka kwezwe ilanga imvula imvelo isilwane isilokazane inyosi Indalo/inhlalo
weather forest river landscape sun rain nature animal Insect Bee environment
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HUMAN INFLUENCE
Target audience:
This part me be introduced to older pupils exclusively, because of the complexity of the topic.
Basic learning goals: •
Introduction to some more advanced terms concerning humans and their influence on the environment
•
Understanding the importance of these terms regarding their impact on the environment
•
Understanding the reason behind waste collection and recycling
•
Understanding the concepts of most important human influenced cycles, e.g. Carbon and Nitrogen
•
Drawing a sketch of a simplified nutrient cycle
Advanced learning goals: •
Pupils may come up with an idea what could be done with recycled waste
•
Pupils may write a text about the importance of recycling and waste collection.
•
Pupils may visit the plant husbandry to apply their knowledge from class on recycling of human waste.
20
DEWATS The basic concept of the DEWATS may be explained after consolidation of an expert to the pupils of the school. Here the knowledge acquired by the pupils may be applied and deepened. Concepts of recycling and nutrient cycling may be refreshed in a practical manner. A field trip to the plant husbandry using the recycled fertilizers from the DEWATS, may
be beneficial for the learning experience as well.
OTHER IDEAS This chapter may provide some guidance and inspiration to the teachers motivated to introduce concepts in the context of human environment interaction. The examples, terms and concept presented here are only examples and may be cut out or expended depending on the teacher and the level of interest by the pupils. The elements presented here may also be expanded to other school subjects, such as Mathematics, Social Science or any other suitable subject. The authors of this booklet further want to clarify, that there are no boundaries for the teacher’s fantasy and creativity. Some elements may be used in a song, or as part of an art project.
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THE PLANT CYCLE OF NUTRIENTS A CONCRETE EXAMPLE
–
In this section we would like to provide a concrete example on how to integrate a given topic (in this case the Plant Cycle of Nutrients) into a lecture or class. The nutrient cycling of plants is a rather complicated topic, which however can be broken down and simplified and taught to children. In Figure 1, we provided a simple scheme, which could be used in a classroom setting. The cycle starts with the growth of plants, who require nutrients, sunlight, and water to grow. When we grow plants for food, such as corn, we eat the nutrients, which the plants have converted into
human-edible nutrients. Part of those nutrients, we need to live and thrive, however part of it is excreted, especially in urine. Recycling human urine, into plant fertilizer and bringing it back to the fields, will reduce human impact on the environment and end the plant cycle of nutrients starts again.
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Figure 1: The plant cycle of nutrients, explained with easy to understand images and pictures, which could be used in a classroom setting
Fertilizer is applied on the plant
Plant feeds on nutrients
Urine is treated to be used as fertilizer
Humans eat plant-based meals
Nutrients are still in human waste
Nutrients are digested in the body
Most of the nutrients are used for living functions
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7. SCHOOL The fertilizer can be used to grow a garden. On these two pages you can find some examples of flowers bushes or trees you can grow using the self-made fertilizer.
NATAL BOTTLE BRUSH
•
Drought resistant
•
Acid pH
•
Flowers in Spring
•
Shrub/small tree
SEPTEMBER BELLS
•
Likes full sun
•
Attracts carpenter bees Flowers in spring
CLIVIA
•
Doesn’t like direct sun
•
Flowers in spring
SAGEWOOD
•
Attracts insects and birds
•
Large shrub
•
Resistant to most pests and diseases
24
L GARDEN BLUE FELICIA
•
Needs a lot of sun
•
Does not like too moist conditions
•
Flowers in summer
CORDIA AFRICANA
•
Likes well drained soils
•
pH 5-6
•
Flowers in summer
RED HOT POKERS
•
Drought tolerant
•
Attracts hummingbirds and butterflies
• ANGEL’S FISHING ROD
•
Needs humus rich soil
•
Likes full sun
•
Needs well drained soils
25
Virtually disease free
26
8. REFERENCES SCIENTIFIC LITERATURE:
Martin TMP, Esculier F, Levavasseur F, Houot S. Human urine-based fertilizers: A review. Crit Rev Environ Sci Technol. November 2020:1-47.
Mchunu N, Odindo A, Muchaonyerwa P. The effects of urine and urineseparated plant nutrient sources on growth and dry matter production of perennial ryegrass (Lolium perenne. L). Agric Water Manag. 2018 Morgan JB, Connolly EL. Plant - Soil Interactions : Nutrient Uptake. Nat Educ Knowl. 2013. Ranasinghe ESS, Karunarathne CLSM, Beneragama CK, Wijesooriya BGG. Human Urine as a Low Cost and Effective Nitrogen Fertilizer for Bean Production. Procedia Food Sci. 2016. Semalulu O, Azuba M, Makhosi P, Lwasa S. Potential for Reuse of Human Urine in Peri-urban Farming. In: Innovations as Key to the Green Revolution in Africa; 2011. ONLINE RESOURCES:
www.sanbi.org (Retrieved May 19, 2021) www.gardenia.net (Retrieved May 18, 2021) www.tropical.theferns.info (Retrieved May 19, 2021) www.gardeninginsouthafrica.co.za (Retrieved May 20, 2021) wenr.wes.org/2017/05/education-south-africa (Retrieved May 20, 2021)
www.generationgenius.com/videolessons/plant-parts-video-for-kids/ (Retrieved May 20, 2021)
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A project by: Marion Meyers Sibilla Guillén Carla Eschmann Silja Müller Samuel Wildhaber Salisa Ziebart