Removal of tetracyclines and estrogens with simultaneous ammonia retention in swine wastewater by aerobic treatment under short sludge retention time.

Simultaneous denitrification and phosphorus removal accomplished by denitrifying biofilters assembled with innovative sulphur-fly ash ceramic carriers.

One-stage hollow-fiber membrane bioreactor for wastewater treatment and resource recovery through hydrogen-driven mixotrophic nitrogen assimilation.

Denitrification in Hangzhou Bay: The role of nutrient dynamics in a tidal and human-impacted estuarine system.

Mesophilic fermentation explorations for anaerobic carboxylates production from commercial bioplastic products: PHA-based cups & PLA-based lids.

Simultaneous removal of nitrogen and manganese via autotrophic denitrification driven by iron-carbon micro-electrolysis in an upflow anaerobic sludge blanket (UASB) reactor.

Recent advances on micro-polluted water remediation by full-scale constructed wetlands: Pollutant removal performance, key influencing factors, and enhancing strategies.

Deciphering the effects of cascade reservoirs on phytoplankton communities in a karst river: Importance of super-large reservoirs.

Enhancing anaerobic digestion of polyhydroxybutyrate through combined pretreatment: Effects on solubilization, methane potential, and long-term continuous thermophilic digestion.

Micro-granular sludge driven by powder carrier in membrane bioreactor: highly-efficient N & P removal and membrane fouling alleviation.

Pioneering application of endogenous denitrification in full-scale industrial wastewater treatment plants via in-situ retrofit.

Hydrochemical characteristics, evolution, and controlling factors of a karstic river with reservoirs: Insights from spatial-temporal analysis.

Low-dose chlorite drives stable nitrite accumulation for partial denitrification.

Overcoming elemental sulfur bioavailability limitations with sponge iron coupling for enhanced nitrate removal: Novel perspective on electron transfer and iron-nitrogen-sulfur metabolism.

Ultrafine partial nitritation-hydroxyapatite granules facilitate stable high-rate partial nitritation of anaerobic digestate of waste activated sludge.

Revalorization of organic waste through psychrophilic anaerobic co-digestion: Insights from fluorescence spectroscopy and kinetic evaluation.

Biochar-calcium peroxide composite for sustained tebuconazole removal via adsorption and surface-mediated oxidative degradation.

The optimization of volatile fatty acid (VFA) production from complex wastes under anaerobic conditions remains constrained in terms of productivity by the common use of long hydraulic retention times (HRTs, 20-30 days). Extended HRTs can limit process productivity by reducing substrate turnover and reactor throughput, while promoting further conversion of VFAs into methane and other end products. Despite its importance, the combined influence of pH and HRT on VFA yields and process optimization has not been comprehensively evaluated. This study investigates the effects of pH and short HRT on VFA production, microbial community structure, and hydrolysis and acidification efficiency in continuous stirred-tank reactors (CSTRs) fed with carbohydrate-rich feedstock (carrot residue pulp). Operating at an HRT of 11 days and an organic loading rate (OLR) of 4.4 g COD·L-1·d-1 at 25 °C under pH 5.1 resulted in a VFA bioconversion efficiency of ~45% and an acidification efficiency of 84%, without compromising VFA profile or productivity compared to reactors operated at 14 days HRT and 3.3 g COD·L-1·d-1. The shorter HRT and higher OLR enhanced hydrolysis efficiency (60%) and promoted greater microbial diversity, supporting robust hydrolytic activity and stable production dominated by acetic and butyric acids. These findings challenge the conventional assumption that longer retention times inherently improve process stability and demonstrate that operational conditions might improve reactor space-time yield in VFA-oriented fermentations.

Municipal wastewater (MWW) was treated using a microalgal–bacterial consortium without mechanical aeration. An inoculum for the reactor was prepared by acclimatizing Chlorella vulgaris to MWW and supplementing with a small amount of activated sludge. The hydraulic retention time (HRT) and solids retention time (SRT) were progressively reduced from 6.67 to 1.17 d and from 10 to 6.67 d, respectively, to test the process robustness under realistic MWW operation. The COD removal efficiency was 88% at 0.23 kg-COD/m3/d. Mass balance suggested the major nitrogen and phosphorus removal mechanism as assimilation. A high percentage (80%) of oxidized nitrogen indicated an efficient nitrification at all HRTs. Inorganic carbon (IC) balance calculation explained the observed IC dynamics. The chlorophyll a-to-mixed liquor volatile suspended solids (MLVSS) ratio and percentage of nitrite responded to IC limitation and supplementation. The mixed liquor exhibited excellent settleability (sludge volume index: 42 mL/g) with dense algal–bacterial flocs. An increased organic loading rate, however, reduced daytime dissolved oxygen, suggesting limitation under non-aerated conditions. These findings demonstrate the potential of microalgal–bacterial systems to achieve efficient COD removal and nitrification at realistic HRTs without aeration while emphasizing the importance of IC management.

Recent interest in a wasteless future has opined the need to turn waste into a resource and one of such approaches is to treat wastes such as urban agricultural wastes through anaerobic digestion to produce biogas. Although this holds great potentials globally, it has received little attention in Ghana, especially, using single-stage biogas digester at mesophilic condition. The study assessed the performance of a mesophilic single-stage biogas digester for treating urban agricultural wastes. An eight (8) m3 pilot-scale single-stage digester with a manual stirrer operating at 30 oC at hydraulic retention times (HRTs) of 20, 23 and 26 days and flow rates 300 l/d, 260 l/d and 230 l/d, respectively, were used. Cow dung was used as inoculum while pig droppings, cabbage wastes, carrot leaves, jute leaves, amaranth plant and spinach leaves were substrates. Selected physicochemical parameters and some heavy metals were analysed for the inoculum, influent and effluent samples for 24 weeks. Highest TS and VS removal was at HRT 26 days, whereas TN, OC, COD, NO3-, and TP were at HRT 23 days. Heavy metal values were higher in the influent than in the effluent, except for Zn and Pb at HRT 23 days. HRTs 23 and 26 days showed better removal efficiency than 20 days. The system produced 3 m3 of biogas (60 % v/v CH4) daily, equivalent to 2 kWh electricity and 2.5 kWh heat daily. The research is good for farmers and policy makers as it addresses waste and energy issues and the SDGs.