2.5 A way forward … a tool for selecting sustainable sanitation arrangements How to obtain all the information we need? Learning objective: awareness that selecting a sustainable arrangement is more than just a matter of choosing between technical solutions Jan-Olof Drangert, Linköping university, Sweden

Factors pushing the sanitation sector to develop towards sustainability world population increase high population densities in urban areas increased consumption and chemical compounds scarcity of phosphorus and other nutrients Jan-Olof Drangert, Linköping university, Sweden global warming modernity and prestige Private activity Community concern

The role of sanitation in solving the looming water and nutrient crises and global warming - save H2O (demand management) and prevent pollution of H2O - use treated greywater to save on ground- and surface water - sanitise nutrients (P, K and S) from households and restaurants recycle nutrients and organics for food production and soil restoration - reduce emissions of CO2 and other greenhouse gases Jan-Olof Drangert, Linköping university, Sweden

Many framework issues to consider Challenges for the present sanitation arrangements Policies, building codes and other regulations New housing area, densification or retrofit Landscape, soil and groundwater characteristics Wind, temperature variation and rainfall pattern Open areas (gardens etc.) and urban agriculture Availability (intermittent supply?) and cost of water Availability (intermittent supply) and cost of energy Collection and recirculation of solid waste, organic waste in particular, etc. Jan-Oloof Drangert, Linköping university, Sweden

Up to now the WC has set the standard, but from now on the resilience of nature will do so El Grand Canal, Mexico City with ”treated” effluent Wastewater and stormwater drainage in Bangalore, India Courtesy of Ian Adler, IRRI-Mexico J-O Drangert, Linköping university, Sweden 5

A new approach for sustainability The discharged waste is an unlimited resource! - if it is clean enough The crucial question to ask is therefore: ”What comes out at the end of the sanitation system?” There is no scarcity of natural resources for households – only poor management of the natural resources we already command! Jan-Olof Drangert, Linköping university, Sweden 6

Where is sludge treated and where does it end up ? Always start your investigation from the end of the process Screen Sedimentation aeration clarifier outflow Where is sludge treated and where does it end up ? Where does the treated effluent flow ? Jan-Olof Drangert, Linköping university, Sweden

Start from the end ! (centralised example) Our thinking is now on global challenges as well as on local wishes for system performance and status Sludge drying bed We decide what quality we would like the final products to have. CO2 & methane gases Dried sludge itself percolating leachate J-O Drangert, Linköping university, Sweden 8

Treated greywater = clean water? Jan-Olof Drangert, Linköping university, Sweden

Treatment results for small and large water utilities More than 2,000 persons Treatment results for small and large water utilities Less than 2,000 persons Jan-Olof Drangert, Linkoping university, Sweden 10

A holistic sanitation selection algorithm ON/OFF Is there an aim/policy of reuse or sustainability? no Make alliances and find your way around yes Is there enough space and infiltration/evaporation capacity on site? Is simplified sewerage affordable ? Is wastewater quality a major concern/problem? no no yes On-site reuse of safe wastewater no yes yes yes Is wastewater pollution caused by excreta? Can the pollution be eliminated through source control ? no greywater no Is swale/open ditch possible? yes yes yes Is treatment on site effective & affordable? yes Is household organic waste sorted ? no Is diversion of urine an affordable option ? no yes yes yes Is infiltration or other reuse safe ? Is settled sewerage affordable ? Can faecal matter be composted on site? Can urine be stored and used on site? yes Compost and use nutrients on site yes no yes no Is biological treatment affordable & safe? yes yes no no Reuse of polished water yes Energy for household yes Is biogas reactor feasible on site ? Fertilise garden no problem yes Swale/fish pond Jan-Olof Drangert, Linköping University, Sweden Collection & reuse off site

Time to search for technical solutions!

A new housing area in central Stockholm Courtesy of Stockholm Water, Sweden

Some achievements in the new district - Household water consumption down 40% - Hot water use (35% of total water use) not measured yet, but expected to decrease 15-25% (= energy saving) - Eutrophication of the receiving lake reduced by 50% - 60% of phosphorus and nitrogen returned to agriculture - Green-house effect, acidification, and use of non-renewable energy reduced by 30% Improvements made by resource-saving installations, rather than changes in individual behaviour – so far Next step: residents become partners Jan-Olof Drangert, Linköping university, Sweden

Self-contained housing complex WC 15 L 50 L 10 L 130 L 80 L wetland STP 130 70 L 55 L groundwater recharge well water 80 L groundwater Jan-Olof Drangert, Linköping university, Sweden

A vision for sanitation arrangements   National and local governments provide guidelines for installation and operation of eco-friendly arrangements. A single household or a housing company can find eco- friendly products in ordinary hardware shops and outlets for contractors. Small and large contractors, plumbers and engineering firms, architects are familiar with the requirements of eco-friendly installations.    Jan-Olof Drangert, Linköping university, Sweden 16