Low-pressure subsurface porous diffuser irrigation system for kitchen wastewater reuse in urban vegetable cultivation: A review of hydraulics, clogging, and automation

By 2050, up to 2.4 billion people are expected to be affected by urban water scarcity, which has led to an interest in the reuse of kitchen wastewater as a low-cost irrigation resource.Previous research has shown that clay pot irrigation is a traditional water-use-efficient irrigation method that can be used with moderately saline water and is several times more efficient than conventional irrigation.This review aims to compile the latest literature on the hydraulics, clogging, and Internet of Things (IoT) based automation of such systems for urban vegetable production using kitchen wastewater.Seepage rates have been previously determined under clean water conditions, and simple pretreatment has been found to significantly reduce organic and solid loads.But previous clogging tests, which were mostly conducted with saline, sediment-laden or synthetic wastewater, not with real kitchen wastewater, have shown that hydraulic degradation is very severe under poor water quality, which is why pretreatment is necessary.Earlier research on IoT integration shows that low-cost reference pot level sensing loops can be used to automate refilling, but they are not able to detect individual emitter clogging.Favorable yield and water productivity gains have been reported in prior agronomic and economic studies, but not under actual kitchen wastewater.Together, these results suggest technical feasibility and highlight key areas of long-term hydraulic, agronomic, and economic validation that require integrated field testing prior to household-scale adoption.