Bench-scale treatability study of a dilute synthetic dairy wastewater, by combined anaerobic-aerobic systems, at ambient temperature conditions

This research project consisted of studying the feasibility of a combined UASB-activated sludge process configuration for treating a dilute synthetic substrate, simulating a dairy wastewater, at a laboratory temperature averaging 23.5 +/- 0.8°C. The bench-scale experimental work was carried-out in two parallel biotreatment systems fed in series. They consisted of relatively small-scale Upflow Anaerobic Sludge Blanket (UASB) reactors of 3.85 and 3.75 L, respectively, followed by 2 L-activated sludge polishing processes. The feed concentration applied to one of the systems consisted of the minimum influent strength recommended for successful anaerobic treatment (∼1 000 mg CODt/L) while the second system was of the domestic sewage-strength range (∼500 mg CODt/L), achieved by dilution. The mainly soluble complex feedstock used consisted of tap water and Iron Fortified Enfalac(TM) Infant Formula. It was supplemented chemically to ensure that proper (N and P) nutrient requirements were met as well as to increase its buffering capacity and to adjust pH. Three experimental runs were carried out by applying increasing UASB influent flow rates of 2, 4 and 8 L/d, in both systems. (Abstract shortened by UMI.