Presentation on theme: "2.5 A way forward … a tool for selecting sustainable sanitation arrangements Learning objective: awareness that selecting a sustainable arrangement is."— Presentation transcript:
2.5 A way forward … a tool for selecting sustainable sanitation arrangements Learning objective: awareness that selecting a sustainable arrangement is more than just a matter of choosing between technical solutions How to obtain all the information we need? Jan-Olof Drangert, Linköping university, Sweden
world population increase high population densities in urban areas increased consumption and chemical compounds modernity and prestige Private activity Community concern Factors pushing the sanitation sector to develop towards sustainability scarcity of phosphorus and other nutrients global warming Jan-Olof Drangert, Linköping university, Sweden
The role of sanitation in solving the looming water and nutrient crises and global warming - save H 2 O (demand management) and prevent pollution of H 2 O - 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 Jan-Olof Drangert, Linköping university, Sweden - reduce emissions of CO 2 and other greenhouse gases
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 Courtesy of Ian Adler, IRRI-Mexico Wastewater and stormwater drainage in Bangalore, India J-O Drangert, Linköping university, Sweden
A new approach for sustainability The discharged waste is an unlimited resource! - if it is clean enough Jan-Olof Drangert, Linköping university, Sweden There is no scarcity of natural resources for households – only poor management of the natural resources we already command! The crucial question to ask is therefore: What comes out at the end of the sanitation system?
Where is sludge treated and where does it end up ? Always start your investigation from the end of the process Where does the treated effluent flow ? Screen Sedimentation aeration clarifier outflow 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 percolating leachate Dried sludge itself We decide what quality we would like the final products to have. J-O Drangert, Linköping university, Sweden Sludge drying bed CO 2 & methane gases
Treatment results for small and large water utilities More than 2,000 persons Less than 2,000 persons Jan-Olof Drangert, Linkoping university, Sweden
A holistic sanitation selection algorithm Is wastewater quality a major concern/problem? yes Is there enough space and infiltration/evaporation capacity on site? Is there an aim/policy of reuse or sustainability? no Make alliances and find your way around yes no yes On-site reuse of safe wastewater Is wastewater pollution caused by excreta? no yes Is treatment on site effective & affordable? yes no yes Is diversion of urine an affordable option ? yes ON/ OFF Is settled sewerage affordable ? yes Can urine be stored and used on site? yes Can faecal matter be composted on site? Is household organic waste sorted ? yes Compost and use nutrients on site yes Is simplified sewerage affordable ? yes no Is infiltration or other reuse safe ? no Is swale/open ditch possible? yes Reuse of polished water no yes Is biological treatment affordable & safe? no Fertilise garden yes Swale/fish pond Can the pollution be eliminated through source control ? greywater Is biogas reactor feasible on site ? Energy for household yes Collection & reuse off site yes Jan-Olof Drangert, Linköping University, Sweden no problem
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 Improvements made by resource-saving installations, rather than changes in individual behaviour – so far - Green-house effect, acidification, and use of non-renewable energy reduced by 30% Next step: residents become partners Jan-Olof Drangert, Linköping university, Sweden
Self-contained housing complex WC STP L 55 L groundwater recharge wetland groundwater well water 80 L Jan-Olof Drangert, Linköping university, Sweden 50 L 80 L 10 L 70 L 25 L 15 L
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