Meeting stringent environmental and reuse requirements with an integrated pond system for the twenty-first century

It is a long sought desire to modernize stabilization pond systems by incre asing their efficiency to control malodors, to save land requirements and t o improve their effluent quality, particularly for reuse purposes, while st ill capitalizing on natural energy saving processes such as anaerobiosis an d photosynthesis. A full-scale demonstration modern integrated pond system was constructed in the town of Arad (22,000 inhabitants) located in the Neg ev desert of Israel. The integrated pond system is composed of the followin g units: (1) anaerobic covered ponds of which one is of the "submerged tent " novel design. including biogas collection and utilization for heating the bottom sludge; (2) two facultative ponds with internal recirculation; (3) a two stage rock filter to biologically remove excess algal biomass from th e effluent; (4) three storage reservoirs operating in a sequential array of "fill, stay, draw", and (5) a seasonal reservoir. The final effluent is ai med at irrigation of various agricultural crops.