Treating wastewater with high oil and grease content using an Anaerobic Membrane Bioreactor (AnMBR). Filtration and cleaning assays

Abstract

An Anaerobic Membrane Bioreactor (AnMBR) pilot plant was studied to improve certain operational conditions of AnMBRs that treat high oil and grease wastewaters discharged from a snacks factory. A comparison of its performance and behavior was made with an upflow anaerobic reactor throughout the first eight weeks of its operation. Raw snack food wastewater was characterized by oil and grease concentrations of up to 6,000 mg/l, with chemical oxygen demand (COD) and biological oxygen demand (BOD(5)) concentrations of up to 22,000 and 10,300 mg/l, respectively. The AnMBR achieved COD removal efficiencies of 97% at an organic loading rate (OLR) of 5.1 kg COD/m(3) d. The filtration flux, and the suction, backwash and relaxation times for each cycle were all varied: an 11 min filtration time involving 10 s pre-relaxation, 20 s backwash and 70 s post-relaxation was finally selected. The filtration flux for long-term operation was between 6.5 and 8.0 l/m(2) h. The study also tested physical cleaning strategies such as intensive backwashing cycles and extended relaxation mode, and different chemical cleaning methods, such as chemically enhanced backwash on air and chemical cleaning by immersion.

Optimization of Anaerobic Membrane Bioreactor Operation for Brewery Wastewater Treatment

“…Constant biogas recirculation rate of 12 LPM was used in the entire study, corresponding to a scouring rate about 15.3 m 3 /m 2 /hr, similar to the reported value 17.6 m 3 /m 2 /hr in the earlier hollow fiber AnMBR study over high strength industrial wastewater (Diez et al, 2012). Over the 140 days study period, the transmembrane pressure (TMP) had increased 2.0 kPa while maintaining constant flux operation at 8 LMH (Figure 3-10).…”

“…In this study, it was found that the soluble protein at 325 ± 25 mg/L in permeate could not be further biodegraded by anaerobic digestion, which makes up the majority of the COD in effluent. hollow fiber AnMBR operation study (Diez et al, 2012). Over the 90 day study period, the TMP was monitored, and average daily cycle TMP, as well as the determined critical fluxes are reported in Figure 4-16.…”

Membrane reactors for biogas production and processing

“…A high BOD to COD ratio indicates that wastewater can be readily biodegradable because of the high fraction of oxidizable organic materials content. Another example is an AnMBR pilot plant treating snacks factory wastewater with high oil and grease content (Diez, Ramos, & Cabezas, 2012). Several full-scale AnMBRs have been applied to the biological treatment of highstrength wastewater.…”

Sustainable Agro-Food Industrial Wastewater Treatment Using High Rate Anaerobic Process

“…An intermittent feeding strategy at an OLR of 4.8 g COD L [19]. Diez et al [58] reported that an anaerobic membrane bioreactor (AnMBR) removed 97% of the COD of oil and greasy wastewater (COD of 22 g L −1…”