Sanitation
4 . Disposal or reuse by aircraft and catering , and the remaining volume is produced by other aviation-related businesses . The on-site wastewater treatment plant biologically purifies water to a quality fit for discharge into local waterways . 7
Safely treated poo can be used for energy generation or as fertilizer in food production .
Using safely treated wastewater and waste byproducts in agriculture and other sectors is increasingly considered a method of combining water and nutrient recycling , increasing household food security and improving nutrition for poor households . The growing interest in wastewater use is driven by scarcity of water and nutrients . However , care is needed to mitigate the health and environmental risks .
CASE STUDIES
Biologically purifying wastewater before discharging . The effluent volume from Schiphol Airport , Amsterdam , is comparable to that of a small city with a population of 45,000 . About half of the wastewater originates from passengers and businesses at the airport , 25 % is discharged
Decentralized excreta management and local greywater reuse in a peri-urban community : El Alto , Bolivia . The systems installed by the project collect and treat urine and faeces separately , for resource recovery and agricultural reuse . Faeces is composted with worms ( vermicomposting ), while urine is treated by storage . Greywater from basins and showers is channelled to small constructed wetlands in the household ’ s garden , with ornamental and edible plants . Testing found that both water and excreta products were safe to reuse , including for food production . The excreta-derived fertilizers ( vermicompost and treated urine ) have been found to be even more nutrient-rich than organic fertilizers commonly used in the region ( such as cow manure ), as evidence by both nutrient testing and crop yields . Potato yields from plants fertilized with human vermicompost and urine were double those of plants fertilized with cow manure . The household systems installed by the project include urine-diverting dry toilets , to minimize water use . The UDDTs have a single vault , in which faeces is collected in 100-litre plastic containers and urine in 20-litre jerry cans . The containers are collected using pickup trucks , and transported to the common treatment plant . Faecal matter is vermicomposted for eight to nine months using red Californian earthworms . 8
Use of wastewater in farming . It is estimated that more than 40,000-60,000 km 2 of land is irrigated with inadequately-treated wastewater or polluted water ,
7 UN-Water : World Water Development Report 2017 : ‘ Wastewater : An untapped resource ’: http :// www . unwater . org / publications / publications-detail / en / c / 853650 /
8 Extract from UNEP and SEI ( 2016 ): ‘ Sanitation , Wastewater Management and Sustainability ’: https :// www . sei-international . org / mediamanager / documents / Publications / SanitationWastewater & Sustainability-Chapter9-Case-studies . pdf
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