Biological treatment of dairy industry wastewater in a membrane bioreactor
(part 2)

Summary

The technology of biological treatment of dairy wastewater is described that provides for meeting the standard maximum permissible concentrations for fishery water bodies. The results of the experimental studies in a pilot membrane bioreactor with real wastewater of «Pestravskii» butter factory are presented. The main process and kinetic parameters of the biological wastewater treatment processes have been obtained that are needed for designing a membrane bioreactor with nitrification-denitrification that provides for meeting the standard maximum permissible concentrations for fishery water bodies or requirements to the effluents discharged into a public sewer. The maximum specific rate of diary wastewater pollutants oxidation V_max at 7 g/l activated sludge concentration and 20 °С temperature is 40 mg/(g·h), Michaelis constant K_m – 15 mg/l, inhibition coefficient of metabolism products – 0.54 l/g, temperature constant X for aerobic heterotrophic conversion – 0.079 deg^–1. Compared to the traditional treatment facilities the use of biomembrane technology at the wastewater biological treatment stage provides for 1.4–1.5 reducing the treatment time, reactor volume and footprint owing to the increase of the oxidation capacity of the aeration units by increasing the activated sludge concentration to 10 g/l; and ensuring almost complete removal of suspended solids by eliminating the tertiary treatment stage. Possible elimination of chemical flotation stage before biological treatment is shown that provides for reducing the expenditures for expensive chemicals and streamlining the process flow scheme.

Ключевые слова

wastewater , biological treatment , activated sludge , membrane bioreactor , kinetic constant , dairy factory