Influence of mineral nutrients on high performance during anaerobic treatment of wastewater from a beer brewery

Abstract

The BOD of wastewater from beer breweries is around 2,000–3,000 mg/ l, which is considered to be low-strength wastewater; however, high-strength wastewater, known sometimes as trübe wastewater (BOD, about 80,000 mg/ l), is also produced as a result of the filtration of wort. This high-strength wastewater was found not to respond well to treatment by a mono-phase thermophilic methane fermentation process using an anaerobic fluidized-bed reactor. Considering the composition of the wastewater and the pathway for methane fermentation, NH 4 + at 500 mg/ l, Ni 2+ at 7 mg/ l, Co 2+ at 2 mg/ l and Fe 3+ at 30 mg/ l were added to the wastewater. After five-fold dilution by volume, the diluted wastewater treated anaerobically in the same manner. As a result, the TOC (total organic carbon) concentration in the effluent was constant at about 400 mg/ l, and no further problems were encountered. The volumetric loading rate of TOC was studied by treating variously diluted samples of high-strength wastewater (TOC 15,000, 23,500, 47,000 mg/ l). The results obtained with the raw wastewater (TOC 47,000 mg/ l) were remarkably good, with a maximum volumetric loading rate of TOC of 14 g/ l·d, a gas yield of 1.2 l/g TOC consumed and a methane content of 59%. From tests involving omission of the mineral nutrients, it appears that Ni 2+ and Co 2+ play important roles in the anaerobic treatment of the wastewater.