1.3 Physical Resource Flows From where do resources come, and where do they end up? Linear flow What comes in …… Water 20-200 kg/p/day Food 2 kg/p/day household Consumer goods Energy 1- ? kg/p/day > 1 kg/p/day Jan-Olof Drangert, Linköping University, Sweden … must go out Urine 1.5-3 kg/d/p Faeces 0.3 kg/d/p pollutants Greywater 20-200 kg/p/day household Solid waste 1 - ? Kg/d/p Jan-Olof Drangert, Linköping University, Sweden The trick is to bend today´s many linear resource flows • Solid waste is the most visible output. It may be discarded or sorted and recycled. Scavengers perform an important service • Faecal matter is very small in volume, but is a major health threat unless treated and used wisely • Urine (urine) volumes are small. Smells may be a problem unless urine is returned to the soil • Grey water is voluminous and a major challenge in dense areas but can be a useful product if handled well • Storm water may be a serious problem or it can augment household and irrigation supplies • Energy is invisible but heat may be recovered Jan-Olof Drangert, Linköping University, Sweden Water and nutrient ’kretslopp’ food Rural home City with linear flows Wastewater = (grey water, urine, and faeces) food wastewater WWTP water Leaking pipes Sorting city J-O Drangert, Linköping University, Sweden Three examples of ’kretslopp’ thinking Fraction: In Stockholm Solid ‘waste’ sorted in 8 fractions, Provides collected and reused In Kimberley No sorting, burnt in situ, the rest to landfill heating/energy No sorting, collected and put on landfills Organic ‘waste’ Faecal matter Urine (urine) Grey water Storm water organics composted Provides together with soil hygienconditioner ised dry faecal material In Kampala banana peels etc to animal feed Soil conditioner dried and composted Soil conditioner dried composted Soil and conditioner collected and trucked toLiquid farm fertiliser used in situ or by Liquid fertiliser truck to council gardens in situ or collected in situ after Irrigation water biological treatment Grey water to pond after biological treatment, and rainwater to the same pond. Little rain. Infiltrated in situ and to drains and biogas infiltration (no heavy Groundwater rains) recharge Liquid fertiliser In drains but flooding due to heavy rains Jan-Olof Drangert, Linköping University, Sweden Material Flow Analysis for human settlements MFA uses the principle of balance: input = output + accumulated stock in the system and provides a systematic description of the flow of goods, materials or substances through various processes and out of the system. output Process 1 input Process 3 Process 2 output Jan-Olof Drangert, Linköping University, Sweden A resource flow model for a hamlet 8 Courtesy of Jenny Aragundy, Ecuador The Stockholm model to improve sustainability 9 Courtesy of Stockholm Water Company Modelling the situation (MFA) • Select the material, product or chemical you are interested in • Decide the boundaries of your system (dashed line) • Include all the flows, uses, losses and disposals agriculture • Find estimates for all flows and stocks food consumption urine faeces livestock waste handling deposit/ landfill 4 STEPS in modelling: hydrosphere Description of the system (2) Formulation of model equations, (3) Calibration, and (4) Simulation incl. sensitivity and uncertainty analysis (1) Jan-Olof Drangert, Linköping University, Sweden Actual reuse of nutrients from households in urban agriculture Example 1: Proportion being reused 100% Glass, tins, ceramics Heavy metals 50% waste pits +urine diversion +WC 1910 1870 only WC 1950 +WWTP stop 2000 Jan-Olof Drangert, Linköping University, Sweden Ex. 1 con´t Examples of ranges for parameters Table 1: Data for the pri mar y and s econdar y was te tre atment for Li nköping, 1870 -2000 Year No of inhabitants Primary was te treatment/ toilet s ys tem 0% WC 10% water-tight buckets 90% dug pit/outhous e 2% WC 5% urine s eparation 30% water-tight buckets 63% dug pit or equiv. 8% WC 16% urine s eparation 76% water-tight buckets 0% pit latrine or equiv. 20% WC 10% urine s eparation 70% water-tight buckets 50% WC 0% urine s eparation 50% water-tight buckets 1870 7 300 1885 10 700 1900 14 500 1920 26 900 1940 38 650 1950 54 500 90% WC 10% water-tight buckets 1975 78 000 100% W C Co mments Level 3 bas ed on (1) Level 3 bas es on (1) 80-100% to s oil 0-20% to anima l fodder Level 3 bas ed on (1) 80-100% to s oil 0-20% to anima l fodder Level 3 bas ed on (2) 95-100% to s oil 0-5% to animal fodder Level 2 (3) 40-60% to s oil 40-60 % to landfill Level 2 (4) was tewater treatment plant (WWTP), no P reduction unit WWTP with 90% of P to s ludge; 0-20% to plant/s oil WWTP with 95% of P to s ludge; 20-30 % reus ed (of which 2/ 3 to energy fores t and 1/3 to farmers ) 70-80% to landfill WWTP with 97% of P to s ludge; 21% reus ed (10-40%) (of which 2/ 3 to energy fores t and 1/3 to farmers ) 79% to landfill (6), (7) 1990 82 600 100% W C (5), (6), (9) 2000 94 000 100% W C (5), (8), (9) Sources : Neset and Drangert, 2010 Secondary was te treatment or s torage 70-90% to s oil 10-30% to anima l fodder Co mments 60% of W C connected to WWTP All W C connected to WWTP s ame as s umptions as for the year 2000 Ex. 1 con´t Sensitivity analysis Phosphorus reuse and phosphorus losses 1870-2000 The filled curves represent calculated averages, while coloured areas between the dotted curves indicate uncertainty ranges due to estimated input data (in kg phosphorus per capita per year) Source: Neset and Drangert, 2010 Example 2: Eutrophication of Lake Dianchi, China 385 tonnes Farmland P leakage 55% of TP 33 tonnes Kunming city Jan-Olof Drangert, Linköping University, Sweden Ex. 2 Cont Urban P flow to Dianchi Lake, China Dianchi roof runoff street runoff denitrification runoff industrial discharge separate storm water drainage storm sewer wrong connection bath sludge kitchen laundry HH urine flush comb. sewer WWTP CSO tank faeces flush infiltration incl. river water treated wastewater overflow out of CSO tank overflow out of combined sewer exfiltration Source: Huang et al., 2007 Ex 2 Con´t Outcome to guide a new strategy 1. Even with the best available treatment technology (BAT with 98% P removal etc.) the discharge would still be twice what the lake can accommodate. 2. A major problem is that during heavy rains the wastewater bypasses the WWTP and washes all wastewater straight into the lake. 3. Groundwater and stormwater enter the poor-quality sewers and make up a large portion of the water coming to the WWTP 4. Source-control measures such as urine-diversion toilets and P-free detergents and body care products are necessary to avoid discharging untreated wastewater downstream the lake and just moving the environmental problems. Source: Huang et al., 2007 Example 3 : P flows through Hanoi City Source: Montangero et al., 2004 Ex. 3 con´t Phosphorus flows in Hanoi City Organic waste collection Water supply Households On-site sanitation Sewerage & drainage Market Agriculture Landfill Composting Courtesy of Agnes Montangero, 2007 Ex. 3 cont 2007 (3 M) Feeding the people of Hanoi - a sensitivity analysis Business No septic as usual tanks No-meat diet 2015 (5 M residents) Source: Montangero et al., 2007 Example 4: Nutrients and food security – a global view Only 1/5 of the P in mined rock reaches the food on our forks! Ex 4 cont. Securing a sustainable phosphorus future Source: Cordell, Neset, White & Drangert 2009 The future is not all dark! Strategies for sanitation improvements Principle: • Organic ≠ other solid waste • Stormwater ≠ sewage • Industrial ≠ household wastewater • Black toilet water ≠ greywater • Faeces ≠ urine Jan-Olof Drangert, Linköping University, Sweden