Design and start-up of a high rate anaerobic membrane bioreactor for the treatment of a low pH, high strength, dissolved organic waste water

Abstract

A Submerged Membrane Anaerobic Reactor (SMAR) is being developed for the treatment of waste water originating in Sasol's coal to fuel synthesis process. The laboratory-scale SMAR uses A4-size submerged flat panel ultrafiltration membranes to induce a 100% solids-liquid separation. Biogas gets extracted from the headspace above the anaerobic mixed liquor and reintroduced through a coarse bubble diffuser below the membranes. This induces a gas scour on the membranes that avoids biomass immobilization and membrane fouling. The substrate is a high strength (18 gCOD/l) petrochemical effluent consisting mostly of C2 to C6 short chain fatty acids with a low pH. Because of this, the pH of the reactor has to be controlled to a pH of 7.1. Organic Loading Rates of up to 25 kgCOD/m3 reactor volume/d has been observed with effluent COD normally <500 mgCOD/l and FSA <50 mgN/l with no particulates >0.45 microm at hydraulic retention times of 17 hours. 98% of the COD is converted to methane and the remainder to biomass. Mixed Liquor (MLSS) concentrations >30 gTSS/l can be maintained without deterioration of membrane fluxes, even though the Diluted Sludge Volume Index (DSVI) indicates that the sludge cannot be settled. No noteworthy deterioration in membrane performance has been observed over the 320 day operational period.

Optimization of Anaerobic Membrane Bioreactor Operation for Brewery Wastewater Treatment

“…More importantly, anaerobic digestion can convert the organic contents in the wastewater into an usable energy source by producing biogas. Van Zyl et al(2008) reported a 2.02 kWh energy per kg COD removed, about 7 times higher than the amount required for the system operation.…”

Anaerobic Membrane Bioreactor as Highly Efficient and Reliable Technology for Wastewater Treatment—A Review

“…), bio waste from municipal solid waste, sludge from wastewater treatment plants, could be utilized [41]. AnMBRs can convert up to 98% of the influent COD into biogas and very small sludge production is normally observed due to the low growth yield of anaerobic micro-organisms, [42] [43]. Organic wastes rich in carbohydrates, such as bio waste and corn silage, can improve the biogas production and the proportion of CH 4 [41].…”

Development and Applications of Anaerobic Membrane Bioreactor in Japan

“…sludge process: high removal efficiency and loading rate, better control over solids retention time and hydraulic retention time (HRT), and high biomass concentrations allowed in the reactor (Aquino et al 2006;Akram and Stukey 2008a;Van Zyl et al 2008;Yuan et al 2008). Grethlein H.E.…”

“…9.1a and 9.1b. Among the three, most studies of AnMBRs were conducted for the submerged configuration (Van Zyl et al 2008;Hu and Stuckey 2006;Akram and Stuckey 2008b;Bohdziewicz et al 2008;Walker et al 2009). (c) External submerged AnMBR.…”