Natural Water Systems and Treatment Technologies to Cope with Water Shortages in Urbanised Areas in India Technical Note for Urbanised Areas in India: Sludge Drying Reed Bed

Sludge drying reed bed (SDRB) is a technology adopted to treat sludge from septic tanks, latrines, or anaerobic and aerobic reactors. The sludge is loaded by pumping on vegetated beds, and treated by a combination of physical and biochemical processes. The dewatering of the sludge is due to a combined effect of drainage and evapotranspiration. The organic matter reduction of the sludge is driven by aerobic mineralization and biological stabilization. The reed plants strongly favour both physical drainage (roots develop preferential paths within the sludge) and biological processes (roots promote a higher biological activity and a more efficient composting if compared to the common sun drying beds). The dewatered sludge, if showing an appropriate final quality (i.e. not containing too many heavy metals or other harmful pollutants) can be used in agriculture, i.e. as soil conditioner. SDRBs are cheaper and more eco-friendly than traditional sludge treatment technologies, and more effective in comparison to classical sludge sun drying beds.