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This work establishes methods of reducing the amount of methane produced from the anaerobic treatment of piggery wastewater by either reducing the storage time before solid/liquid separation or inhibiting the activity of methanogens in anaerobic wastewater treatment system. Experimental results showed these two methods can be adopted effectively to reduce methane production resulting from anaerobic piggery wastewater treatment. First, the wastewater must be processed using solid/liquid separation immediately after washing pig houses. This process can reduce by 62% the biogas production and indirectly decrease the methane production from the anaerobic wastewater treatment reactor. Second, adding 10 mg L−1 bromochloromethane (BCM) daily into the anaerobic wastewater treatment reactor can significantly reduce the amount of biogas and methane produced during the anaerobic fermentation process. Furthermore, biogas production can be completely inhibited after 4 days. Adding BCM (≤10 mg L−1) to wastewater only slightly affected the efficiency of the anaerobic wastewater treatment process. Results in this study can provide the basis for further research on reduction of the amount of methane produced from anaerobic wastewater treatments. [ABSTRACT FROM AUTHOR]

Aims: To isolate aerobic denitrifying bacteria which will be applied to piggery wastewater treatment facilities for enhanced nitrate and nitrite removal. Methods and Results: Nitrate-supplemented basal medium in airtight, crimp-sealed serum bottles containing an atmosphere of 92% oxygen was inoculated with denitrifiers, strains NS-2 and SM-3, and incubated at 30°C. After 20 h, the concentration of nitrate was decreased rapidly by both NS-2 and SM-3. Nitrite production was almost zero during the whole experimental period for both strains. Nitrogen gas production peaked at the 20 h for both NS-2 (8·20 ± 1·03 mmol l–1) and SM-3 (3·93 ± 0·16 mmol l–1). Conclusions: Strain NS-2, which produced the highest N2 concentration in this work, was identified as Pseudomonas stutzeri. This strain is the most capable of aerobic and anaerobic conversion of nitrate to N2 without forming a nitrite intermediate. Significance and Impact of the Study: Strain NS-2 is highly promising for future application in in situ piggery wastewater treatment. [ABSTRACT FROM AUTHOR]

This work aims to evaluate the efficiency of ammonium removal from piggery wastewater by an intermittent aeration (IA) sequencing batch reactor (SBR) with immobilized NH4(+)-reducing bacteria under mesophilic conditions. When a 20-L bench-scale SBR with 11% (v/v) of alginate beads containing NH4(+)-reducing bacteria was used, removal efficiency of NH4(+) was 63% after 240 h. When a full-scale SBR system (available volume = 83 m(3)) with 0.1% (v/v) of alginate-coated light-expanded clay aggregates beads containing NH4(+)-reducing bacteria was used, removal efficiency of NH4(+) by the full-scale intermittent aeration SBR (IA-SBR) was significantly different from both traditional intermittent aeration SBR (T-SBR) and the continuous aeration SBR with AL beads containing NH4(+)-reducing bacteria (P < 0.05). In summary, the IA-SBR with AL beads can significantly promote removal efficiency of NH4(+) on farm.