Combined compact anaerobic reactors and lamella settlers for decentralized sewage treatment

This work presents a compact plant's development and performance evaluation for the decentralized treatment of domestic sewage. The plant was conceived and installed in a house with four residents in Vicente Pires, Federal District, Brazil. Its purpose was to remove organic matter and solids using a low-cost biological treatment process that was simple to operate. The plant was essentially anaerobic, composed of an up-flow anaerobic reactor and an anaerobic filter, both associated with lamella settlers. It was operated under real conditions and monitored for nineteen months, with removal efficiencies (calculated over the medians) of 81% for COD, 83% for BOD, 51% for Total Solids, 55% for Total Volatile Solids, 87% for Total Suspended Solids, and 100% for Settleable Solids. The plant performed adequately, with no clogging between the plates of the lamella settlers, no offensive odours, and limited amounts of sludge and scum.