Module 4.10 Ecosan versus conventional sanitation How can dry UD ecosan system be compared with a conventional systems (open defecation, latrine pit, water-borne)?

4 Swedish systems with nutrient recovery compared 1.Reference. Conventional system. N & P removal in WWTP. Effluent: 8 mg N & 0.24 mg P/l. Sludge incinerated, ash landfilled. 2.Urine. 80% of urine diverted & recycled as fertiliser. Rest = reference 3.Blackwater. Vacuum toilets. Collected blackwater anaerobically digested, sanitised & recycled as fertiliser. Rest = reference 4.Sludge. Sludge recycled as fertiliser. Rest = reference

Recycled plant available NPKS

Energy use

Total use non-renewable

Other studies of sorting systems Many systems analysis have found same results: Urine diversion – decreases water emissions – gives lots of useful fertiliser – saves chemical fertiliser – saves energy

Recycled NPK vs degree of diversion

Water emissions vs degree of diversion

Energy usage vs degree of diversion

Energy usage vs transport distance

System boarders What to include and what to exclude? UDD – Solid organic waste – Energy production – Fertiliser production Food production – Delivered sanitational function Greywater Drinking water Other waste

Productive Sanitation N=2.8kg P=0.4kg K=0.5 kg Nutrient flow per person and year Food Excreta Fertiliser

Value of fertiliser - urine 2.8kg N = 6kg Urea 0.5/kg = kg P = 2kg TPS ~0.4/kg = kg K = 1kg KCl ~0.4/kg = 0.4 Total value 4.2 per person and year = per person day Value per jerry can 20L ~ 0.23 Can at least pay for transport and spreading Non-subsidised

Cost for ecosan Pour flush toilet 1900 INR (35) EcoSan toilet4200 INR (77)

Fertiliser per family NPK Indian, price 5.5 INR/kg (0.1) Value 880 INR/year (16) Present value years 2-10: 5070 INR! (93)

Conclusion Pour flush toilet cost: 1900 R EcoSan toilet cost: 4200 R – Income from fertiliser: 5080 R Fertiliser can pay for toilet in 10 years, not just additional cost! Additionally Less hazard to ground & surface water – Saves on drinking water – Protects health

Cost sharing Having no toilet has lowest investment & direct running costs! Only type of toilet where the investment can directly pay off The cost of Ecosan is compatitive compared with any other ecological solution The cost is largely paid by household when building – no risk for corruption at municipal level – higher cost acceptance More private enterprise – more competition – saves taxes