Biological treatment of dairy industry wastewater in a membrane bioreactor (part 1)

Summary

The results of research study in the field of biological treatment of dairy wastewater are presented. The studies carried out under contact conditions showed that the kinetics of oxidation of dairy wastewater pollutants with activated sludge can be described by enzymatic reactions equation for substrate inhibition; at that, the obtained inhibition constants point at the increase of the wastewater toxicity after chemical flotation for biological treatment processes. The technology has been proved with simulative effluent in a pilot membrane bioreactor. The kinetic dependences of organics oxidation by BOD_full, nitrification and denitrification were determined. The increase of oxidation capacity of the facilities by 1.46 at the sludge concentration increase from 4 to 10 g/l is shown that allows reducing significantly the size of the biological treatment facilities when using MBR technology. In the course of experimental studies at MBR plant and kinetic experiments under contact conditions the coefficients of inhibition with activated sludge metabolism products were determined for the simulative solution of wastewater by BOD_full, for nitrification and denitrification. The temperature constant value for aerobic heterotrophic conversion, for nitrification and denitrification processes has been found.

Key words

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

Membrane Technologies: Past, Present and Future (the North America as an Example)

SUMMARY

Basic tendencies in the field of development of membrane processes for water and wastewater treatment in the North America are covered. Main characteristics, basic trends and features of the use of membranes including membrane bioreactors are presented. Characteristics necessary for assessment and selection of the best membrane technologies for each certain project are compared. Membrane treatment has become the fastest growing sector in water treatment, wastewater treatment and water desalination. Four types of membranes are used according to membrane pore size: microfiltration (MF), ultrafiltration (UF), nanofiltration (NF) and reverse osmosis (RO). All four principal types of membrane guarantee the removal of the entire spectrum of water pollutants and can be used as a stand-alone technology for a majority of applications. Integrated membrane processes combining different membrane types are becoming a cutting edge approach to meet strict water/wastewater quality regulations because they allow the smallest possible system size, minimize chemical consumption, and provide the most cost-effective solution for the greatest number of applications.

Key words

potable water , wastewater treatment , reverse osmosis , ultrafiltration , desalination , membranes , microfiltration , nanofiltration , membrane bioreactor