Paradigm shift in Nutrient-Energy-Water centered sustainable wastewater treatment system through synergy of bioelectrochemical system and anaerobic digestion.

With advancements in research and the necessity of improving the performance of bioelectrochemical system (BES), coupling anaerobic digestion (AD) with BES is crucial for energy gain from wastewater and bioremediation. Hybridization of BES-AD concept opens new avenues for pollutant degradation, carbon capture and nutrient-resource recovery from wastewater. The strength of merging BES-AD lies in synergy, and this approach was employed to differentiate fads from strategies with the potential for full-scale implementation and making it an energy-positive system. The integration of BES and AD system increases the overall performance and complexity of combined system and the cost of operation. From a technical standpoint, the primary determinants of BES-AD feasibility for field applications are the scalability and economic viability. High potential market for such integrated system attract industrial partners for more industrial trials and investment before commercialization. However, BES-AD with high energy efficacy and negative economics demands performance boost.

Evaluation of foam-glass media in a high-rate filtration process for the removal of particulate matter containing phosphorus in municipal wastewater.

Foam-glass as an effective filter media in a high-rate filtration process was evaluated for the removal of particulate matter containing phosphorus in municipal wastewater. The foam-glass with a low sphericity exhibited a higher porosity (60.2%) and a lower apparent specific gravity (0.50 g/cm3) compared with a conventional sand media (35.1% and 1.19 g/cm3). In particular, the high porosity of the foam-glass increased its surface area for capturing particles with coagulation, leading to a significantly decreasing head loss in the filtration bed column, resulting in a significantly longer filtration duration (more than 2 times) and a slightly higher removal of contaminants (approximately 4.8% for a suspended solid and 2% for the total phosphorus). Additionally, while backwashing of the conventional sand media required about 30% of the bed volume, the low specific gravity of the foam-glass media could be expanded to 100% of the volume due to its lower energy demand. Based on these advantages, it is expected that the foam-glass media will have a vital role as an alternative media in high-rate filtration processes.

Effects of beneficial microorganisms on nutrient removal and excess sludge production in an anaerobic-anoxic/oxic (A2O) process for municipal wastewater treatment.

The performances of anaerobic-anoxic-oxic processes with (A2O-B) and without (A2O-C) beneficial microorganisms were compared to provide valuable insights on how they are affected by changes in the microbial biomass and community composition. Although the A2O-B process showed lower concentrations of mixed liquor suspended solids and mixed liquor volatile suspended solids than the A2O-C process under identical operating conditions, the A2O-B process was more effective for the removal of organic materials and nutrients compared with the A2O-C process. Furthermore, the compressibility and settleability of the activated sludge were significantly better in the A2O-B process than in the A2O-C process due to the enhanced decomposition of extracellular polymeric substances. These results indicated that the inoculation of beneficial microorganisms may increase the proportions of microorganisms in relation to the removal of organic materials, nutrients (i.e., Zoogloea, Dechloromonas, Nitrospira, and Nitrosomonas) and the reduction of the excess sludge (i.e., Proteobacteria and Bacteroidetes).

High-rate algal pond coupled with a matrix of Spirogyra sp. for treatment of rural streams with nutrient pollution.

This study evaluated the unique features of a filamentous algae matrix (FAM) that can be applied to high rate algal ponds (HRAPs) as a promising way to remove nutrient from polluted rural streams. The results show that the HRAPs, coupled with the FAM, effectively removed nitrogen and phosphorus (79.8% and 81.2%, respectively), and achieved high production of DO, with a maximum of 11.0 g O2 g FAM-1 d-1. The FAM functioned wells as a screen to prevent excessive algae loss from the system and obtained relatively high biomass growth rate (0.032 mg L-1 d-1 for nitrogen and 0.344 mg L-1 d-1 for phosphorus). The harvested FAM was a useful fertilizer and the rate of addition of FAM were 1.52 kg d-1 ha-1 of nitrogen and 0.44 kg d-1 ha-1 of phosphorus. Thus, combining the HRAP with the FAM was an effective nutrient removal and resource utilization system for rural streams.

Citric acid and ethylene diamine tetra-acetic acid as effective washing agents to treat sewage sludge for agricultural reuse.

This paper presents the effects of different concentrations of citric acid (CA) and ethylene diamine tetra-acetic acid (EDTA) when used as additive reagents for the treatment of sewage sludge for agricultural use. Herein, both the retention of nutrients and removal of metals from the sewage sludge are examined. The average removal rate for the metals after treatment by CA decreased in the order Cu>Pb>Cd>Cr>Zn, while the rates after treatment by EDTA decreased in the order of Pb>Cu>Cr>Cd>Zn. After treatment with CA and EDTA, total nitrogen and total phosphorus concentrations in the sludge decreased, while the content of available nitrogen and Olsen-P increased. In addition, a multi-criteria analysis model-fuzzy analytic network process method (with 3 main factors and 12 assessment sub-factors) was adopted to evaluate the effectiveness of different treatment methods. The results showed that the optimal CA and EDTA concentrations for sewage sludge treatment were 0.60 and 0.125 mol/L, respectively.