Introduction to composting Course 2 Unit 6 Part c and d Teacher:
Mariska Ronteltap [email protected] Slide 2 * Engineered =
manufactured with a composting chamber unlike the Arborloo (see
Course 1 Unit 3), which works like a very basic soil composting
toilet (good for rural areas) The term dry toilet is often used for
composting toilets, but once again, this can be misleading.
Example: Dry Toilet Club of Finland Part C Engineered composting
toilets Part D Examples and case studies Slide 3 Engineered
composting toilets overview Composting toilets are more difficult
to operate than dehydrating toilets, e.g. they need optimal
moisture content for the biological process of composting
therefore, composting toilets are less applicable for most
sanitation projects in low-income countries (compared to UDD
toilets) Proposed optimal conditions for micro-organisms
responsible for composting: Moisture content range from 50-60%, 10%
Composting toilets can also treat household organic waste (this
increases the C/N ratio) It is useful to know what the composting
toilet market looks like in Europe (to prove that toilets without
water are not just for poor people in developing countries!) Course
2 Unit 6 Slide 4 Composting toilets, example Berger Biotechnik The
following 5 slides were provided by Wolfgang Berger, whose company
(Berger Biotechnik GmbH) is the market leader for composting
toilets in Germany Since 1985 we have sold about 450
TerraNova-Composting toilet systems and about 15,000 biological dry
toilets (SAWI, TOA, Separett u.a.). TerraNova, SAWI and TOA are our
own products. In the last 5 years, there were about 25 larger
projects (number reducing) and about 3000 small systems (stable
figures). The main market for our big projects (TerraNova) is
Germany, Austria, Switzerland, but also several islands in the
Mediterranean or Atlanic. BERGER BIOTECHNIK GmbH eMail:
[email protected] Internet:
[email protected] A publication by
Wolfgang Berger on this topic is available under Extra Materials
Slide 5 Composting system for toilet and kitchen waste (indoors)
Schematic of air ventilation Opening for emptying Composting
container Slide 6 Toilet pedestal with seal in lid Removable insert
for easier cleaning Drop pipe from higher floors (straight fall for
faeces) Toilet pedestals and drop pipes for faeces (can be with or
without urine diversion) Slide 7 10 m drop pipe for faeces with 0.3
m diameter; 14 m ventilation pipe with 0.15 m diameter 4-storey
building with public Kindergarten (in Germany) Course 2 Unit 6
Slide 8 Use the natural slope to position the composting vessel
below the toilet Public composting toilets in the Alps and national
parks Slide 9 After 2 years of composting, the compost can be
applied as soil conditioner for flower beds, about 2 L per m and
year Final product the loop is closed Slide 10 Other examples of
composting toilets (there are many suppliers on the market) BioLet
Company: http://biolet.com/products/ne.htm Nature Loo Company:
http://www.nature-loo.com.au/toilets/systems/ensuite.html Sun-Mar
Company: http://www.sun-mar.com/products/excelne.php Slide 11 Costs
of composting toilets They can be quite expensive
http://www.gtz.de/en/dokumente/gtz2009-en-
technology-review-composting-toilets.pdf and
http://www.gtz.de/en/dokumente/en-ecosan-pds-
030-automated-compost-toilet-asahiyama-zoo- 2006.pdf
http://www.gtz.de/en/dokumente/gtz2009-en-
technology-review-composting-toilets.pdf
http://www.gtz.de/en/dokumente/en-ecosan-pds-
030-automated-compost-toilet-asahiyama-zoo- 2006.pdf Costs can be
high due to proprietary designs Often marketed at the high end
market e.g. for wealthy, eco-minded people in Germany They should
not require a secondary treatment step for faeces anymore (this is
integrated into the toilet) Course 2 Unit 6 Slide 12 Video clips on
composting toilets There are many video clips on YouTube on this
topic (mostly composting toilets without urine diversion), e.g.
http://youtube.com/watch?v=wNMs9oiPuvo (short documentary of
National Geographic) http://youtube.com/watch?v=wNMs9oiPuvo
Urine-diversion composting toilet at a Germany adventure
playground: http://www.c-studios.net/ecosan/ Slide 13 Course 2 Unit
6 Part D: Examples and case studies Course 2 Unit 6 Slide 14
Example 1: Home composting of dried faeces and kitchen waste
(garden of Richard Holden, Johannesburg, South Africa) Slide 15
Back to Richard Holdens house in Johannesburg, South Africa:
Richard adds the faeces bucket of his UDD toilet to his composting
heap (a handfull of compost is added to the bin after each
defecation event, as well as toilet paper) (remember: this system
was mentioned already in Course 1 Unit 3 Part E) this is not
Richard Holden, but my husband Steve, demonstrating how it is done
Slide 16 Composting unit at front of house (note gaps in bricks for
ventilation) Slide 17 The compost is removed from the bottom of the
heap with a spade (and the compost is then taken to a second
composting heap in the back garden (see next slide)) Course 2 Unit
6 Slide 18 Final compost product; also used to line faeces bin and
as additive to faeces bin after defecation Second compost heap in
the garden, on which urine is applied (urine jerry can is emptied
manually onto that compost heap twice per week). The photo shows
Elisabeth doing this activity (actually quite difficult to do this!
- heavy) Slide 19 More practical details on Richards home
composting system Internal dimensions: 600 x 700 mm (900 mm above
ground and 400 mm below ground) One lintel* across the body of the
composter above the lower opening to hold the compost up. The
composter can be made from anything, mud block wood etc. The secret
is to keep moist, aerobic and turn. Also the composter has kitchen
waste in it (far more in volume terms than the excreta), toilet
paper and the dry soil that is used for odour control. As for
pathogen destruction Chris Buckley in KZN was testing a sample,
Aussie Austin at CSIR has already. The problem is that the family
doesn't have worms so cannot test for them. Temperature, time and
biological activity all contribute to making the contents safe.
Recently in my garden compost I threw a dead rat. In less than one
month all trace of the rat had disappeared. Lately I have been
adding a comfrey** soaked in water over 10 days. It smells like raw
sewage but seemd to turbocharge the composting process. *Lintel: a
beam across something ** Comfrey is some herb Source: E-mail from
Richard Holden, May 2007 Slide 20 Example 2: Co-composting of
faecal sludge with organic solid waste The following five slides
were provided by Doulaye Kon, SANDEC/Eawag, Switzerland
(www.sandec.ch) - this technology will also be mentioned again in
Course 2 Unit 7 (faecal sludge management) Co-composting means:
having two (or more) different input materials Course 2 Unit 6
Slide 21 Case study: Co-composting of faecal sludge with organic
solid waste in Kumasi, Ghana (1/5) Faecal sludge is high in N;
organic solid waste is high in C; together they give a suitable C:N
ratio for composting Investigated impact of turning compost heap at
pilot scale Operated one month at high temperature and 3 months in
total Measured indicator is helminth eggs Reminder: Faecal sludge =
urine, faeces and some water Mature compost during curing phase
Slide 22 22 Discharge of faecal sludge Sludge drying beds Organic
solid wasteCompost maturation Co-composting process (2/5) Dewatered
faecal sludge (solids) Liquid (drainage) to other treatment Slide
23 Temperature was higher than 45C for 4-6 weeks (this results in
pathogen kill) Heap 1, turned when temp > 60 Heap 2 turned each
10 days 30 45 60 75 010203040506070 Days Temperature (C)
Heap11Heap12 Heap21Heap22 Temperature development during
co-composting of dewatered FS and organic solid waste (3/5) Slide
24 Number of helminth eggs (HE) in final product: < 10 / g d.s.
Viability of helminth eggs in final product: < 10 %
Co-composting ensures hygienisation Recommendation for use of
biosolids in agriculture: 3-8 HE / g d.s. (based on WHO ww reuse
guidelines; Xanthoulis + Strauss, 1991)a Ascaris egg inactivation,
results from pilot-scale co-composting (4/5) Course 2 Unit 6 Days
of composting Total number of eggs per g d.s. Viable number of eggs
per g d.s. Number of eggs per g d.s. Final product Slide 25 25
Optimum mixing ratio (regarding porosity, humidity, C/N): FS* :
other compostable materials = 1: 3-10 *75-96% water content
Co-composting design criteria (5/5) Design criteria: -C/N ~ 25-30
-Humidity ~ 50-60% -pH ~ 6-8 -Windrow size 1 m 3 -Aeration (forced
or natural) Process measurements: -Temperature measurement (expect
T=55-65C during thermophilic phase) Approximate C/N ratio for some
compostable materials 1 : -Nightsoil ~ 6-10 -Weeds ~ 19 -Farmyard
manure ~ 14 -Wheat straw ~ 128 -Fresh sawdust ~ 511 -Fruit wastes ~
35 -Refuse ~ 30-80 1 Obeng and Wright (1987) The Co- composting of
Domestic Solid and Human Wastes UNDP/World Bank Slide 26 Relevant
websites Composting in general: www.kompost.de (organisation in
Germany which issues the quality assurance certificates for
compost; site contains only little information in English
www.kompost.de www.compostnetwork.info (The Network is a
collaboration of partners, promoting sustainable practices in
composting, anaerobic digestion and other treatment procedures for
organic residues across Europe. It aims to address the needs of
both practical operators and decision makers.)
www.compostnetwork.info Composting toilets www.berger-biotechnik.de
www.berger-biotechnik.de www.drytoilet.org/index.html (Dry Toilet
Club in Finland) www.drytoilet.org/index.html Slide 27 References
Tchobanoglous, G., Burton, F.L., Stensel, H.D. (2003) Wastewater
Engineering, Treatment and Reuse, Metcalf & Eddy, Inc.,
McGraw-Hill, 4th edition. This is a good general conventional
wastewater treatment book Rothenberger, S., Zurbrgg, C.,
Enayetullah, I., and Maqsood Sinha, A. H. M. (2006) Decentralised
composting for cities of low- and middle-income countries - A
users' manual, Eawag/Sandec (Switzerland) and Waste Concern
(Bangladesh), Dbendorf, Switzerland. Available: www.sandec.ch. *
Vodounhessi, A., and von Mnch, E. (2006) Financial and
institutional challenges to make faecal sludge management
integrated part of ecosan approach: Case study of Kumasi, Ghana.
Water Practice and Technology (selected proceedings of the Beijing
Biennial IWA Congress), 1 (2) Available:
http://62.189.20.32/wpt/001/wpt0010045.htm
