Treatment of dairy wastewater with a membrane bioreactor

Abstract

-Among the food industries, the dairy industry is considered to be the most polluting one because of the large volume of wastewater generated and its high organic load. In this study, an aerobic membrane bioreactor (MBR) was used for the treatment of wastewater from a large dairy industry and two hydraulic retention times (HRT), 6 and 8 hours, were evaluated. For both HRTs removal efficiencies of organic matter of 99% were obtained. Despite high permeate flux (27.5 L/h.m²), the system operated fairly stablely. The molecular weight distribution of feed, permeate and mixed liquor showed that only the low molecular weight fraction is efficiently degraded by biomass and that the membrane has an essential role in producing a permeate of excellent quality.

Preparation and characterization of antifouling graphene oxide/polyethersulfone ultrafiltration membrane: Application in MBR for dairy wastewater treatment

“…However, MBRs present a potentially suitable environment for PAOs proliferation because the high biomass concentrations in MBRs might lead to microzone of anoxic or anaerobic within the sludge flocs [54]. In the case of conventional biological treatment systems, partial removal of phosphorus occurs through its assimilation by the biomass for cellular synthesis [4,39]. Also, it is possible that a part of phosphorous removal found in the existing study was related to biological assimilation by PAOs and other microorganisms [39].…”

“…The seeding source of the reactor was taken from a working wastewater treatment plant (Bisotoon, Kermanshah, Iran) and fed with MPW wastewater for 3 months and there was no sludge discharge and the system operated as wise batch. The operating conditions were: HRT of 6 h and MLSS of 6000, 10,000 and 14,000 mg/L (the defined values were based on existing literature and previous tests as explained elsewhere [4,39]). Variations within ±5% of effluent COD concentration at each condition were considered as the criterion for steady state conditions.…”

“…It generates about 1-10 L of effluents/L of processed milk [3] and comprises a high concentration of organic material such as proteins, Upflow anaerobic sludge blanket XRD X-ray diffraction retention of all microorganisms and viruses, higher biodegradation efficiency, smaller footprint, better quality of treated water, higher solids retention time (SRT), independence of hydraulic retention time (HRT), and easy control [11]. MBRs also present better removal efficiency of micropollutants, recalcitrant organic pollutants and slowly biodegradable pollutants due to the absolute rejection of these compounds by the membrane [4] and the high biomass concentration. However, membrane fouling, which raises operating costs related to membrane material/replacement, performance maintenance and also diminishes the membrane module life time, is still a major problem that restricts the wide application of MBR [12,13].…”

Performance of nano-filtration and reverse osmosis processes for wastewater treatment

“…43 Also, studies show that NF is an efficient treatment system for secondary or tertiary effluents aiming at the generation of water for industrial, agricultural, or indirect potable reuse. 44,45 …”

Reuse of Dairy Wastewater Treated by Membrane Bioreactor and Nanofiltration: Technical and Economic Feasibility

“…This is due to its ability to operate with higher biomass concentrations than conventional systems, proving better biodegradation of the organic compounds in the effluent. Moreover, the presence of the membrane ensures complete removal of suspended solids and also partial retention of compounds with low biodegradability, either from the effluent itself or generated by the microorganisms, that remain in the reactor longer than the average for TDH and may thus be degraded by the biomass (Bernhard et al, 2006;Andrade et al, 2013).…”