A microbial electrochemical hybrid system for simultaneous sludge treatment, acid production, and desalination

Assessment of kinetic parameters for the mesophilic anaerobic biodegradation of two-phase olive pomace

Integrating entrapped mixed microbial cell (EMMC) process for biological removal of carbon and nitrogen from dilute swine wastewater.

A fuzzy-logic-based model to predict biogas and methane production rates in a pilot-scale mesophilic UASB reactor treating molasses wastewater

Application of halophiles in air cathode MFC for seafood industrial wastewater treatment and energy production under high saline condition

Non-sealed water hastens the efficiency of microbial electrochemical remediation system

Micro-electricity utilization performance and microbial mechanism in microbial fuel cell powered electro-Fenton system for azo dye treatment

Enhanced sludge degradation process using a microbial electrolysis cell in an up-flow anaerobic sludge blanket reactor with ultrasound treatment

The effectiveness of carbohydrate addition and the use of ultrasonication as a pretreatment for the mesophilic anaerobic digestion of saline aquacultural sludge was assessed. Analyses were conducted using an anaerobic sequencing batch reactor (ASBR), which included stopped gas production attributed to the saline inhibition. After increasing the C : N ratio, gas production was observed, and the total chemical oxygen demand (TCOD) removal efficiency increased from 75% to 80%. The TCOD removal efficiency of the sonication period was approximately 85%, compared to 75% for the untreated waste. Ultrasonication of aquaculture sludge was also found to enhance the gas production rate and the TCOD removal efficiency. The average volatile fatty acid (VFA) to alkalinity ratios ranged from 0.1 to 0.05, confirming the stability of the digesters. Furthermore, soluble chemical oxygen demand (SCOD), VFA, and PO4 3− concentrations increased in the effluents. There was a 114% greater gas generation during the ultrasonication period, with an average production of 0.08 g COD/L·day−1.

The objective of this study was to evaluate the optimal location of ozonation within biological treatment for a typical tannery wastewater by giving special attention to biodegradability‐based chemical oxygen demand (COD) characterization. As treating the raw tannery effluent solely by biological treatment is not adequate to meet the discharge standards owing to the high level of biorecalcitrant COD at the outlet, the application of chemical oxidation, i.e. ozone together with biotreatment (pre‐ozonation or in mid‐ozonation or post‐ozonation) was investigated. The tannery effluent under investigation had initially inert soluble COD (SI1) and particulate COD (XI1) fractions corresponding to 9% and 13% of the total COD (CT1), respectively, whereas each component of the biodegradable part—readily biodegradable COD (SS1), rapidly hydrolysable COD (SH1), and slowly hydrolysable COD (XS1)—accounted for around 26% of the total COD (CT1). Pre‐ozonation, undesirably competing with biotreatment for the removal of degradable organics, was shown to be insufficient both in terms of total COD (CT1) and inert COD (CI1) removal efficiencies. The scheme of biological treatment + ozonation + biological treatment could be applied successfully when 42.8 mg O3 min−1 was introduced for 5 min with a utilized ozone percentage of 76% at a point in biological treatment where the readily biodegradable COD (SS1) was depleted through biochemical reactions. Such an alternative yielded satisfactory outcomes when both total COD (CT) and inert COD (CI) removal efficiencies per utilized ozone ratios were considered. With post‐ozonation, on the other hand, the highest inert COD (CI) removal efficiencies together with an effluent quality meeting the discharge standards could be obtained. Copyright © 2006 Society of Chemical Industry

Improvement of methane production from waste activated sludge by on-site photocatalytic pretreatment in a photocatalytic anaerobic fermenter

Enhanced chromium recovery and simultaneous sludge degradation in a novel bioelectrochemical system assembled with bio/abio-cathodes

Cassava stillage is a high strength organic wastewater with high suspended solids (SS) content. The efficiency of cassava stillage treatment using an anaerobic sequencing batch reactor (ASBR) was significantly enhanced by discharging settled sludge to maintain a lower sludge concentration (about 30 g/L) in the reactor. Three hydraulic retention times (HRTs), namely 10 d, 7.5 d, 5 d, were evaluated at this condition. The study demonstrated that at an HRT of 5 d and an organic loading rate (OLR) of 11.3 kg COD/(m(3) d), the total chemical oxygen demand (TCOD) and soluble COD (SCOD) removal efficiency can still be maintained at above 80%. The settleability of digested cassava stillage was improved significantly, and thus only a small amount of settled sludge needed to be discharged to maintain the sludge concentration in the reactor. Furthermore, the performance of ASBR operated at low and high sludge concentration (about 79.5 g/L without sludge discharged) was evaluated at an HRT of 5 d. The TCOD removal efficiency and SS in the effluent were 61% and 21.9 g/L respectively at high sludge concentration, while the values were 85.1% and 2.4 g/L at low sludge concentration. Therefore, low sludge concentration is recommended for ASBR treating cassava stillage at an HRT 5 d due to lower TCOD and SS in the effluent, which could facilitate post-treatment.

A submersible microbial fuel cell (SMFC) was utilized to treat sewage sludge and simultaneously generate electricity. Stable power generation (145 +/- 5 mW/m2, 470 omega) was produced continuously from raw sewage sludge for 5.5 days. The maximum power density reached 190 +/- 5 mW/m2. The corresponding total chemical oxygen demand (TCOD) removal efficiency was 78.1 +/- 0.2% with initial TCOD of 49.7 g/L. The power generation of SMFC was depended on the sludge concentration, while dilution of the raw sludge resulted in higher power density. The maximum power density was saturated at sludge concentration of 17 g-TCOD/L, where 290 mw/m2 was achieved. When effluents from an anaerobic digester that was fed with raw sludge were used as substrate in the SMFC, a maximum power density of 318 mW/m2, and a final TCOD removal of 71.9 +/- 0.2% were achieved. These results have practical implications for development of an effective system to treat sewage sludge and simultaneously recover energy.

Evaluation of system performance and microbial communities of a bioaugmented anaerobic membrane bioreactor treating pharmaceutical wastewater

Nutrient recovery from waste streams, particularly digestate from anaerobic digestion, represents a promising strategy for sustainable waste management and circular economy practices. This study evaluated the performance of electrochemical (ES) and Microbial electrochemical systems (MES) for ammonia recovery from digestate under varying voltages. Energy consumption, and natural pH increase in catholyte were investigated for increased recovery efficiency. The results demonstrate that MES and ES exhibited similar recovery rates, with ammonia recovery reaching approx. 49% at 1.2V, while at lower energy efficiency MES outperformed ES. At '0' voltage, MES achieved a baseline recovery of 31.85%, significantly higher than ES (13.25%), highlighting the contribution of microbial electrochemical activity in driving nutrient recovery with minimal energy input. MES exhibited remarkably lower energy consumption, requiring nine-fold less energy than ES at low applied voltages, owing to the synergistic effects of microbial activity and bioelectricity generation. Moreover, MES minimized ammonium transport losses and showed better stability in cathodic pH variations, favouring long-term operational viability. The findings in MES as a more sustainable alternative for ammonia recovery, emphasizing its potential to global carbon neutrality and operational costs in nutrient recycling processes.