Capturing ammonia from anaerobically digested manure could simultaneously decrease the adverse effects of ammonia inhibition on biogas production, reduce reactive nitrogen (N) loss to the environment, and produce mineral N fertilizer as a by-product. In this study, gas permeable membranes (GPM) were used to capture ammonia from dairy manure and digestate by the diffusion of gaseous ammonia across the membrane where ammonia is captured by diluted acid, forming an aqueous ammonium salt. A lab-scale prototype using tubular expanded polytetrafluoroethylene (ePTFE) GPM was used to (1) characterize the effect of total ammonium nitrogen (TAN) concentration, temperature, and pH on the ammonia capture rate using GPM, and (2) to evaluate the performance of a GPM system in conditions similar to a mesophilic anaerobic digester. The GPM captured ammonia at a rate between 2.2 to 6.3% of gaseous ammonia in the donor solution per day. Capture rate was faster in anaerobic digestate than raw manure. The ammonia capture rate could be predicted using non-linear regression based on the factors of total ammonium nitrogen concentration, temperature, and pH. This use of membranes shows promise in reducing the deleterious impacts of ammonia on both the efficiency of biogas production and the release of reactive N to the environment.

Significant over-strength discharge fees are often imposed on breweries for the disposal of high-strength effluent to sanitary sewers. In this research work, the removal performances of electrocoagulation (EC) compared with operating electrocoagulation and chemical coagulation in sequence (EC-CC) or vice-versa (CC-EC) was examined to determine the capability of treatment in reducing the strength of the wastewater. Optimal operating parameters regarding electrolysis time, initial pH, and applied power were determined in conjunction with nutrient removal performance, electrode consumption and energy usage. Combined EC-CC treatment has been demonstrated to be economically feasible for brewery wastewater applications from an energy consumption perspective due to the efficiency of nutrient removal and the reduction of sewer discharge costs. Treatment by EC-CC at 5 W for 20 min using aluminum electrodes resulted in enhanced and consistent removal efficiencies of 26%, 74%, 76%, and 85% for chemical oxygen demand (COD), reactive phosphorous (RP), total phosphorous (TP) and total suspended solids (TSS), respectively. Energy consumption was the main contributor to operating cost. By considering potential recovered over-strength discharge fees (ODF), EC-CC treatment is economically feasible and beneficial in a brewery wastewater application. The results demonstrated the effectiveness of the CC-EC process to remove phosphorous, organics and solids from brewery wastewater at lower power supply, so that the recovered ODF cost for CC-EC at 5 W-EC is 23% higher than at 10 W-EC.

This research documents two innovative designs of septic tanks used for onsite wastewater treatment. The designs were implemented and tested as part of a research project focused on innovative decentralized wastewater treatment solutions. The modified septic tanks were tested at different hydraulic loading rates for sufficient periods to effectively evaluate their performance. The two systems were designed with successive anaerobic and aerobic chambers and were differentiated between attached and suspended growth. The systems were operated at detention times of 4.3, 3.2, and 2.6 days. High removal of organic load was achieved under all loading criteria in both systems. Effluent BOD₅ concentration at lower and higher loading rates were found to be less than 15 and 25 mg/L, respectively, representing a removal rate of more than 95%. Nitrogen was also removed but at a lower rate. The highest TN removal was achieved (59%) in the attached growth system at the lowest loading rate. Although two logs of E. coli removal (99%) were achieved in all systems, E. coli numbers were high enough to necessitate further tertiary treatment. The modified septic tanks proved to be a cost-effective technology with low energy and O&M requirements.

BACKGROUND: Among the methods to produce hydrogen biologically, dark fermentation stands out mainly due to its low operating requirements. Organic wastes, such as brewing industry waste slurries and glycerol, can provide a cost‐effective feedstock with the additional potential of generating value‐added byproducts, while addressing a wastewater treatment issue.RESULTS: The hydrogen production potential in dark fermentation of a high‐strength brewery waste slurry was optimized with a selected seed sludge, initial COD concentration of 50–60 g L⁻¹, pH 6.4 and fermentation time of 30 h. The main end product was butyric acid, accounting for over 50% of the carboxylic acids. The efficiency of the process on the basis of volume of H₂ obtained per gram of COD converted into organic acids was 393 ± 5 and 430 ± 6 mL without and with glycerol, respectively, and the molar ratio of H₂ per mole of substrate was 71% of the theoretical molar yield when the fermentation is dominated by butyrate as the end product.CONCLUSIONS: A proposed brewery sludge treatment system comprising dark fermentation followed by anaerobic digestion is promising and can be more advantageous than anaerobic digestion alone with an increase of 18.5% in energy potential. Alternatively, with recovery of valuable butyrate, a reduction in 4.5 kg of CO₂ emissions per cubic meter of sludge treated can be achieved, with a 27% net loss in energy potential. © 2023 The Authors. Journal of Chemical Technology and Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry (SCI).