title: Field study comparing the effect of hydraulic mixing on septic tank performance and sludge accumulation.
abstract: This study investigates the effect of hydraulic mixing on anaerobic digestion and sludge accumulation in a septic tank. The performance of a septic tank equipped with a hydraulic mixer was compared with that of a similar standard septic tank over a period of 10 months. The study was conducted in two phases: Phase-I--from May to November 2013 (6 months); Phase-II--from January to May 2014 (4 months). Hydraulic mixing effectively reduced the effluent biological oxygen demand (BOD) and total suspended solids, and reduced the sludge accumulation rate in the septic tank. The BOD removal efficiencies during Phase-II were 65% and 75% in the standard septic tank and a septic tank equipped with hydraulic mixer (Smart Digester™), respectively. The effect of hydraulic mixing reduced the rate of sludge accumulation from 0.64 cm/day to 0.27 cm/day, and increased the pump-out interval by a factor of 3.
authors.affiliation: a Department of Chemical Engineering , Qatar University , Doha , Qatar.|b Clearford Industries Inc ., 515 Legget Drive, Suite 100, Ottawa , ON , Canada K2K 3G4.
authors.forename: Fares
authors.initials: F
authors.lastname: Almomani
mesh_terms: D057919:Biological Oxygen Demand Analysis; D012722:Sewage / Q000032:analysis*; D014865:Waste Disposal, Fluid / Q000295:instrumentation / Q000379:methods*
chemical_list: D012722:Sewage
keywords: Digestion; mixing intensity; pump-out interval; sludge accumulation