1. Composting human waste from waterless toilets
J. F. Hanssen*, A. Paruch**, P. D. Jenssen**
* Department of Biotechnology and Chemistry
** Department of Mathematical Sciences and Technology
The Norwegian University of Life Sciences
Technologies that emerge from applying ecological thinking to engineering
3rd. International Conference on Ecological Sanitation, Durban May

2. Composting toilet Vent pipe Collection/composting compartment
Liquid overflow collection

3. Composting toilet cottages (500 000 cottages)
Major toilet type in Norwegian
cottages ( cottages)
Commonly used in rural homes
in Norway
Used in many other settings
world wide

4. Composting toilet at roadside facility - Sweden
Elected the best
roadside facility
In Sweden 2002

5. Composting toilet at roadside facility - Sweden
Clean odourless
toilets

6. Antartica 2001
The compost reactor presented herein was tested when Erik Sønneland (picture) and Rolf Bae spent almost one year on the south pole preparing for crossing the whole Antartica. See also:
and

7. Secondary composting

8. Composting toilet Volume reduction: 70 - 90% 550 down to 55 liters
(Del Porto and Steinfeld 2000)

9. NH3
Composting toilet
Nitrogen loss
To wet/dry
Hygiene

10. Composting toilet
Nitrogen loss
To wet/dry
Hygiene
To much liquid

11. Composting toilet
Nitrogen loss
To wet/dry
Hygiene

12. Composting toilet Nitrogen loss To wet/dry Hygiene - no system
above 43oC*
- risk of handling
(* Engen 1991)

13. Composting toilets - some challenges
Minimize risk when handling/emptying
Ensure a hygienized compost
Minimizing the nitrogen loss during composting of nitrogen-rich waste
Minimizing the odour emission during composting

14. Secondary composting
Composting
bioreactor
Final hygienized
product

15. Secondary composting
Compost laboratory

16. The compost bioreactor
Return of process water - rich in NH4+
Total volume 750 liter
Compost x
Liquid container
Vacuum pump
Screen

17. Input to the composting bioreactor

18. Influence of time and temperature on destroying pathogens in excreta
(Feachem et al. 1983)

19. Temperature in compost vs. time
Temp oC
Days

20. Results
Temp vs.time Run no.1
Temp vs.time Run no.2

21. Temperature vs. time

22. The compost bioreactor - process control
Return of process water
amount and frequency
Compost x
Liquid container
Vacuum pump
Screen

23. The compost bioreactor - process control
Return of process water
amount and frequency
Compost x
Liquid container
Vacuum pump
Screen

24. Temperature vs.time and addition of process water

25. The compost bioreactor - process control
Pumping
frequency x
Liquid container
Vacuum pump
Screen

26. Ammonia volatilization
NH3
NH4 +

27. The compost bioreactor - process control
Recycling of process water
Controlling air flow
Addition of bulking material

28. The compost bioreactor - process control
Recycling of process water
Controlling air flow
Addition of bulking material
Manual mixing

29. Conclusions
A composting bioreactor for processing of human excreta with other biodegradable organic waste is developed x
Compost

30. Conclusions
The composting bioreactor reduce the nitrogen loss compared to windrow composting, thus producing a more valuable compost x
Compost

31. Conclusions
Secondary composting can produce a safe soil amendment in about two months – in contrast to the generally recommended six months

32. Recommendations
• At least 15 cm of bark should be placed above the filtration screen to enhance leachate drainage.
• Food waste should be chopped to at least 5 cm dimensions.
• Although meat and fish products can be added, large bones should be removed.
• Food waste and excreta should be mixed, not layered.
The leachate evacuation hose should be insulated if exposed to cold temperatures.
The reactor needs weekly maintenance

33. Further investigations
Different concentrations of leachate recycled at different times
Different volumes of different bulking agents
Different mixing schedules
Investigate dieoff of other organisms than coliforms

34. Conclusions
Secondary composting opens for professional collection and treatment of material from composting toilets- thus reducing risk

35. References:
Engen, Ø Hytteklosetter-Alternative avløpsløsninger for hytter og spredt bebyggelse, med hovedvekt på miljøkonsekvenser. SFT/JORDFORSK report no. 1207, Centre for Soil and Environmental Research, Ås, Norway, 68p.
Del Porto, D. and Steinfeld, C. (2000). “The Composting Toilet System Book”. Ecowaters Books, Concord, Massachusetts.