Module 4 10 Ecosan versus conventional sanitation How

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. 2. 3. 4. Reference. Conventional system. N & P removal in WWTP. Effluent: 8 mg N & 0. 24 mg P/l. Sludge incinerated, ash landfilled. Urine. 80% of urine diverted & recycled as fertiliser. Rest = reference Blackwater. Vacuum toilets. Collected blackwater anaerobically digested, sanitised & recycled as fertiliser. Rest = reference 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 http: //www. stockholmvatten. se/pdf_arkiv/english/Urinsep_eng. pdf

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 Excreta Food N=2. 8 kg P=0. 4 kg K=0. 5 kg Nutrient flow person and year N=2. 8 kg P=0. 4 kg K=0. 5 kg Fertiliser

Value of fertiliser - urine 2. 8 kg N = 6 kg Urea 0. 5€/kg = 3€ 0. 4 kg P = 2 kg TPS ~0. 4€/kg = 0. 8€ 0. 5 kg K = 1 kg KCl ~0. 4€/kg = 0. 4€ Total value 4. 2€ person and year = 0. 012€ person day • Value per jerry can 20 L ~ 0. 23€ • Can at least pay for transport and spreading • Non-subsidised • •

Cost for ecosan • • Pour flush toilet 1900 INR (35€) Eco. San toilet 4200 INR (77€)

Fertiliser per family n NPK 10 -5 -20 Indian, price 5. 5 INR/kg (0. 1€) n Value 880 INR/year (16€) n Present value years 2 -10: 5070 INR! (93€)

Conclusion • Pour flush toilet cost: 1900 R • Eco. San 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