Jac Wilsenach Appropriate technologies conference 4 September 2007 BMW Pavilion, V&A Waterfront, Cape Town On-site treatment and beneficial use of waste streams: local case studies

Challenges! 1)Dry region vs sustainable food production 2)Economic growth vs environmental protection 2) Ageing infrastructure vs urbanization 3) Lack of skills vs global development 4) Poverty vs wealth 5) Sustainable systems vs depletion of resources

From linear flux to nutrient recovery

Phosphate - P Potassium - K Nitrogen - N Domestic Wastewater volume Why collect waste streams separately? Load from urineLoad from all other wastewater Load from faeces

Toilet water Grey water Aerobic Rainwater (roof runoff) Storm water (overland) Overflow Composting Organic slowly degradable/inert Containment Bulk drinking water Anaerobic digestion Engineered wetland Overflow Irrigation Solids/Oils ? Nitrification membrane/ biofilm Urban effluent: de-central treatment and recycle Separation Household water Storage Soil Screenings ? Organic easily degradable Sludge thickening/drying Overflow Disinfection Irrigation Disinfection

Oude Molen Philippi Lynedoch Three case studies

Sustainability Institute at Lynedoch Biolytix system Vertically integrated wetland

Biolytix VIW Septic tanks School/ offices Houses Sand filter UV Trunz (uf) Municipal water (40%) Recycle to toilet flushing Irrigation on site Rain Recommendation Treatment processes at Lynedoch

[mg/l]BiolytixWetland COD – 76 NH 4 + -N40 – 50 (= inflow) 0.1 – 0.6 NO N< – 88 PO 4 - -P10 – 15 (= inflow) 1.4 – 2.5 E.Coli /100ml 2,200 – 734,000 0 – 10 Effluent quality at Lynedoch (range of minimum, maximum values measured)

The Businessplace at Philippi 300 – 400 houses, Small enterprises, 7 ha urban agriculture

The Philippi Business Place A multidisciplinary neighbourhood design approach with: Sustainability Institute, School of Public Management and Planning, University of Stellenbosch Noero Wolff Architects Agama Energy CSIR TRIACON Hulme and de Villiers Etc.

Aerobic biofilm Anaerob. Digester Offices/ houses Sand filter UV Municipal water (171 m 3 /d) Recycle to toilet flushing (103 m 3 /d) Compost/ Irrigation on site N2N2 Grey water (171 m3/d) Treatment processes at Philippi - Water Balance Aerobic biofilm Anoxic MLSS Biogas Black water (103 m3/d) Ground water (29 m 3 /d)

Net Food import Wastewater treatment (including bio- denitrification) Agricultural soil needs: kgN/a 1625 kgP/a 1450 kgN/a 1625 kgP/a kgN 2 /a 1450 kgN/a 1575 kgP/a Food consumption and excretion (2500 people) (Based on tomatoes) Local over-supply of nutrients (N)

Aerobic biofilm Anaerob. Digester Offices/ houses Sand filter UV Recycle to toilet flushing (103 m 3 /d) Compost/ Irrigation on site 28 kgN 2 Grey water 139 kgCOD/d 5 kgN/d Treatment processes at Philippi – Mass Balance Aerobic biofilm Anoxic MLSS 18 kgCH 4 Black water 208 kgCOD/d 32 kgN/d 7:1 4 kgN/d 5 kgN/d

Oude Molen EcoVillage development Projexe, Makeka Design Laboratory, Marcussen Architecture, Arcus Gibb, Triocon, Sustainability Institute, Heritage consultant, Environmental consultants,

Aerobic biofilm Offices/ social/ Comm./ Showcase/ houses Sand filter UV Recycle to toilet flushing (45 m 3 /d) Compost/Struvite Exported off site Bath/Shower water 50 m 3 /d Treatment processes at Oude Molen Aerobic/ Anoxic SBR UCT MLSS Black water kitchen water laundry water 189 m 3 /d Urine 1 m 3 /d Irrigation Municipal water 195 m 3 /d MgO

Costs Capital cost of Lynedoch system = R15,000/home (2001) Capital cost of Philippi system = R16,000/home (2006), water saving = R630/home.a Cost to replace/upgrade overloaded Oude Molen = R 75 mil. (R175,000/home, 2004) Reference: N2 Gateway = R15,000/home for water and sanitation infrastructure

Conclusion… a place for decentral systems: Where in terms of relative scale, it is “central” Where central systems fail to keep up with development, Where development takes place on top of and over original design capacity, Where communities can tap into the recycled resources, Where ownership of operation and maintenance can be established.