Model-based identification of biological and pH gradient driven removal pathways of total ammonia nitrogen in single-chamber microbial fuel cells

During the last decade, bioprospecting for electrochemically active bacteria has included the search for new sources of inoculum for microbial fuel cells (MFCs). However, concerning power and current production, a Geobacter-dominated mixed microbial community derived from a wastewater inoculum remains the standard. On the other hand, cathode performance is still one of the main limitations for MFCs, and the enrichment of a beneficial cathodic biofilm emerges as an alternative to increase its performance. Glucose-fed air-cathode reactors inoculated with a rumen-fluid enrichment and wastewater showed higher power densities and soluble chemical oxygen demand (sCOD) removal (Pmax = 824.5 mWm−2; ΔsCOD = 96.1%) than reactors inoculated only with wastewater (Pmax = 634.1 mWm−2; ΔsCOD = 91.7%). Identical anode but different cathode potentials suggest that differences in performance were due to the cathode. Pyrosequencing analysis showed no significant differences between the anodic community structures derived from both inocula but increased relative abundances of Azoarcus and Victivallis species in the cathodic rumen enrichment. Results suggest that this rarely used inoculum for single-chamber MFCs contributed to cathodic biofilm improvements with no anodic biofilm effects.

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Electricity generation and pollutants removal of landfill leachate by osmotic microbial fuel cells with different forward osmosis membranes

10.21203/rs.3.rs-66054/v3 ◽

2021 ◽

Author(s):

Nan Jiang ◽

Li Huang ◽

Manhong Huang ◽

Teng Cai ◽

Jialing Song ◽

...

Keyword(s):

Fuel Cells ◽

Active Layer ◽

Landfill Leachate ◽

Microbial Fuel Cells ◽

Forward Osmosis ◽

Feed Solution ◽

Cellulose Triacetate ◽

Ammonia Nitrogen ◽

Pollutant Removal ◽

Leachate Treatment

Abstract In this study, thin-film composite with embedded polyester screen, cellulose triacetate with a cast nonwoven and cellulose triacetate with embedded polyester screen (CTA-ES) were examined as the intermediate membranes in osmotic microbial fuel cells (OsMFCs). The reactors were fed with actual landfill leachate and the performance was studied in two operation modes: active layer facing draw solution and active layer facing feed solution (AL-FS). The OsMFC with CTA-ES exhibited the best energy generation (maximum power density: 0.44 W m-2) and pollutant removal efficiency (ammonia nitrogen: 70.12 ± 0.28%, total nitrogen: 74.04 ± 0.33%) in the AL-FS mode, which could be ascribed to the lowest internal resistance (236.75 ohm) and highest microbial richness. Pseudomonas was the highest proportion of microbial in OsMFCs. The results of this study has demonstrated the potential of OsMFCs for landfill leachate treatment.

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Study of Biofilter Planted with Basil for Removal of Ammonia in Aquaponic Water

Civil and Environmental Engineering ◽

10.2478/cee-2021-0025 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Bharat Nandkumar Mulay ◽

Konda Rajasekhar Reddy

Keyword(s):

Water Quality ◽

Ammonia Nitrogen ◽

Quality Parameters ◽

Coarse Aggregates ◽

Total Ammonia Nitrogen ◽

Coconut Husk ◽

Significant Difference ◽

Total Ammonia ◽

Water Recirculation ◽

Aquaculture Water

Abstract This experimental investigation of a laboratory scale aquaponic system included testing of a biofilter with basil plant as the biofilter part on aquaculture water quality. Irridescent shark was selected as aquaculture species. The biofilter consist of natural biomaterials such as coconut husk, coco peat, and coarse aggregates. The experiment was carried out for three short water recirculation durations of 2, 3, and 4 h/day. The influent and effluent ammonia NH3, total ammonia nitrogen (TAN), nitrites NO2 and nitrates NO3 levels were measured and analysed. The results showed that the biofilter effectively removed NH3 (65 - 71 %), TAN (34 - 58 %), and NO2 (60 - 67 %) from the aquaculture water. The dissolved oxygen (DO) levels were maintained between 3 - 7.0 mg/l during all the recirculation durations. The significance of water recirculation period was assessed by calculating the differences between the means of water quality parameters with a statistical test named one-way analysis of variance (ANNOVA) with significant level P taken as 5 %, i.e., P ≤ 0.5. The effluent mean NH3 levels 0.030 mg/l, 0.033 mg/l, and 0.022 mg/l exhibited significant difference at 4 h/d periods while effluent TAN levels 0.81, 0.77, and 0.77 showed no difference with varying periods.

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