Application of the single-stage anaerobic membrane bioreactor (1S-AnMBR) for the co-digestion of organic kitchen waste and sewage

Abstract

In the scenario of sustainable technology application, the minimization of waste and resource consumption are more fundamental compared to effluent quality. In recent years, many kinds of researches related to green technology in wastewater treatment have been conducted, such as constructed wetland, membrane bioreactor, etc. With the same perception, the co-digestion of kitchen waste and sewage study was carried out. The principle of this environmentally friendly technology is to create a low-cost pretreatment for domestic wastewater, by taking advantage of the organic carbon available in the leftovers to remove contaminants in the wastewater, improve water quality, reduce excess sludge and save money. The study is aimed to evaluate the carbon and nutrient recovery of a laboratory single-stage anaerobic membrane bioreactor (1S-AnMBR), which included an Up-flow Anaerobic Sludge Blanket (UASB) continuous with an UF membrane bioreactor. The result shown that the obtained COD removals were above 80% at all organic loading rates (OLRs). The effluent COD concentrations were 160±21, 227±45, 340±78, 563±104 and 886±96 mg.L-1 at OLRs of 0.9 to 1.5; 2.0; 3.5; 5.0 and 7.0 kg COD.m-3.day-1, respectively. The biogas yields collected were 1119±76, 1550±68, 2155±80, 3610±86 and 5989±88 mL.day-1 at OLRs of 0.9; 1.5; 2.0; 3.5; 5.0 and 7.0 kg COD.m-3.day-1. High performance of ammonia conversion from organic nitrogen was obtained in the AnMBR. Total nitrogen and phosphorus losses were 12% and 15%, respectively. Transmembrane pressure (TMP) increased to the pressure limit of 45kPa after 11 days of operation at OLR of 5 kg COD.m-3.d-1. Thus membrane fouling is a big challenge for AnMBR. Besides these promising research outcomes, the technology is expected to bring convincing results into practice in the co-digestion of solid wastes and sewage that may be suitable for rural or remote areas, in which solid waste and sewage collection systems are not available.