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Pig farmers in Taiwan tend to overdose copper (Cu) and zinc (Zn) in animal feeds to ensure pig health. The application of Cu- or Zn-rich livestock compost to fields can result in high Cu/Zn residues in surface soil and violate limitations for zinc and copper in land applications. This study aims to extract Cu and Zn from sludge using organic acid or H2O2/organic acids. The livestock bio-sludge was dried and treated with different concentrations of acetic acid (1N, 2N, and 4N). The acid-extracted sludge was then treated with or without adding H2O2 during different periods (4, 24, and 48 h) to investigate the efficiency of acid extraction of Cu and Zn. The supernatant of the acid-extracted product was separated from the residues through centrifugation. Experimental results showed that the treatment set of dried bio-sludge with 2% H2O2 significantly promoted the removal efficiency of Cu and Zn from the bio-sludge (p < 0.01). The best removal efficiency of Cu and Zn from the bio-sludge was 40% and 70%, respectively, using 4N acetic acid in the 48 h group. The study shows a green method for extracting Cu and Zn from livestock sludge, enhancing the sustainability of intensive livestock farming.

The conventional piggery wastewater treatment system is mainly a manual operation system which may be well managed by experienced technicians. However, the pig farmers must simultaneously manage their pig production as well as their on-farm wastewater treatment facility. For this study, Internet of Things (IoT) applications were introduced on a 1000-pig farm to establish a smart piggery wastewater treatment system, which was upgraded from a self-developed fully automatic wastewater treatment system. Results showed that the removal efficiency of biochemical oxygen demand (BOD), chemical oxygen demand (COD), and suspended solids (SS) of the piggery wastewater based on the sensor data before and after water quality sensor calibration were 89%, 94%, and 93%, and 94%, 86%, and 96%, respectively. Moreover, the removal efficiency of BOD, COD, and SS of the piggery wastewater based on the analytical chemical data before and after water quality sensor calibration were 93%, 89%, and 97%, and 94%, 86%, and 96%, respectively. Experimental results showed that overall removal efficiency of BOD, COD, and SS of the piggery wastewater after water quality sensor calibration were 94%, 86–87%, and 96%, respectively. Results revealed that the farm-scale smart piggery wastewater treatment system was feasible to be applied and extended to more commercial pig farms for establishing sustainable pig farming.

Excessive sludge in the wastewater treatment basins has to be removed periodically and collected as the form of sludge cake for promising good water quality of the effluent. This study aims to evaluate the feasibility of biogas production by anaerobic co-digestion of dairy cattle wastewater and crude glycerol from transesterification of sludge cake. Different ratios of crude glycerol, i.e., 2, 4, and 8% (v/v), from the previous experiment were mixed with dairy cattle wastewater and inoculated with anaerobic sludge in cap-sealed 1-L serum bottles as anaerobic digesters. Although the 8% crude glycerol set showed the highest total biogas and methane production, low pH from volatile fatty acid accumulation decreased the removal efficiency of chemical oxygen demand, biochemical oxygen demand, and suspended solids after a 14-d incubation period. The experimental sets with 2 and 4% of crude glycerol increased total methane production up to 177 and 226% compared to the control set, respectively. We found that addition of crude glycerol decreased removal efficiency of total solids and volatile solids. In our study, we proved that slaughterhouse sludge cake is a feasible feedstock for producing biogas through transesterification and anaerobic co-digestion.

The pattern of micro-electricity production of simple two-chamber microbial fuel cells (MFC) was monitored in this study. Piggery wastewater and anaerobic sludge served as fuel and inocula for the MFC, respectively. The output power, including voltage and current generation, of triplicate MFCs was measured using an on-line monitoring system. The maximum voltage obtained among the triplicates was 0.663 V. We also found that removal efficiency of chemical oxygen demand (COD) and biochemical oxygen demand (BOD) in the piggery wastewater was 94.99 and 98.63%, respectively. Moreover, analytical results of Fast Fourier Transform (FFT) demonstrated that the output current comprised alternating current (AC) and direct current (DC) components, ranging from mA to μA.

This study was conducted to evaluate the feasibility of applying a two-step biological treatment process, solid-state anaerobic digestion (SSAD) and black soldier fly larvae (BSFL) composting, for the treatment of dairy cattle manure. Biogas from the SSAD of dairy cattle manure, and the digestate of SSAD was fed to BSFL. In turn, BSFL can be fed to animals as a protein supplement. Adjustment of the pH and 30% inoculation ratio (IR30) during SSAD produced the highest theoretical methane yield, 626.1 ± 28.7 L CH4/kg VSdes, with an ultimate methane yield of 96.81 ± 2.0 L CH4/kg VSload. For BSFL composting, the groups with a feeding rate of 75 and 100 mg/day/larvae had the highest body weight change, which was 969.6 ± 28.4% and 984.1 ± 177.6%, respectively. The combination process of SSAD and BSFL composting increases the incentive for dairy cattle manure treatment instead of conventional composting and produced more valuable products.

The objective of this project is to integrate a farm-scale bio-desulfurization facility with a novel biogas hollow fibre adsorption module for biogas desulfurization and bio-natural gas production. In this study, the desulfurization experimental results showed that the bio-desulfurization system can remove 96.7 ± 6% of H2S from the biogas after an approximately two-month enrichment period. The average CH4, N2, and CO2 concentrations in raw biogas were 63.4, 15.2, and 21.1%, respectively. As for biogas upgrading experiments, the inlet biogas flow rates were applied from 5 to 20 L/min. The removal efficiency of CO2 under all biogas flow rates was 100%. Meanwhile, methane was promoted from 60% to nearly 94% (i.e. 57% increase in methane concentration). The replacement of anthracite and coking coal by upgraded biogas might reduce 44.4% and 42.5% of CO2 equivalent, respectively. The achievement of this project pursues the mitigation of carbon dioxide emissions by using upgraded pig biogas which can be enlarged and extended to all decentralized pig farms worldwide. [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 m3) 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. [ABSTRACT FROM AUTHOR]

The objectives of this work were to isolate and characterize the polyhydroxyalkanoate (PHA) producing bacteria in enriched piggery sludge and make methyl esters from PHA for industrial applications. The strain ECAe24 isolated from piggery sludge with the highest PHA production was selected to produce PHA and then methyl ester by trans-esterification using glucose as substrate under mesophilic conditions. The final product after trans-esterification consisted of approximately 75.39% of fatty acid methyl ester and was identified as decanoic acid-3-hydroxy-methyl ester, octanoic acid-3-hydroxy-methyl ester, and some other contents. The novelty of this study is to use PHA-producing bacteria from piggery sludge to make fatty acid methyl esters which can be used as materials for producing biodiesel from piggery wastes. [ABSTRACT FROM AUTHOR]

This study aimed to improve the utilisation of biogas in pig farms, the promotion of biogas use and the reduction of greenhouse gas (i.e. methane, carbon dioxide, and nitrous oxide) emissions to the atmosphere. Sulfur oxidisers can convert sulfide (S2?) to sulfur (S0) and even sulfate (SO42?). Strains of CYAS-1, CYAS-2, SW-1, SW-2, and SW-3 were isolated from environmental samples and proven to have capabilities of sulfide oxidation by growing them in 150mL liquid media with 1.5g sulfur powder. An increase in sulfate concentration was used to select sulfide oxidisers. Strains CYAS-1 and CYAS-2, which both had significant sulfide oxidation capability, were isolated from the sludge of piggery wastewater treatment facilities. Moreover, strains SW-1, SW-2, and SW-3 were isolated from a pilot-scale biogas bio-filter (BBF) reactor. The experimental results showed that strain CYAS-1 (identified as Acinetobacter spp.), grown in diluted trypticase soy broth (TSB) with sulfur powder, increased the concentrations of SO42? from 17.20.5 to 23.81.0mg/L (38.4% increase). Strain CYAS-2 (identified as Corynebacterium spp.), grown in diluted TSB with sulfur powder, increased concentrations of SO42? from 17.70.1 to 25.90.9mg/L (47.0% increase). Concentrations of SO42? were increased 40.5, 33.6, and 29.7% in the presence of strains SW-1 (Candida kruse/inconspicua; 96.2% identity), SW-2 (Candida parapsilosis; 93.2% identity), and SW-3 (Trichosporon mucoides; 95.7% identity), respectively. [ABSTRACT FROM AUTHOR]

A high concentration of NH in piggery wastewater is major problem in Taiwan. Therefore, in our study, we isolated native heterotrophic nitrifiers for piggery wastewater treatment. Heterotrophic nitrifier AS-1 was isolated and characterized from the activated sludge of a piggery wastewater system. Sets of triplicate crimp-sealed serum bottles were used to demonstrate the heterotrophic nitrifying capability of strain AS-1 in an incubator at 30°C. All serum bottles contained 80 mL medium, and the remainder of the bottle headspace was filled with pure oxygen. The experimental results showed that 2.5 ± 0.2 mmol L−1 NH was removed by 58 hours, and, eventually, 1.5 ± 0.5 mmol L−1 N2 and 0.2 ± 0.0 mmol L−1 N2O were produced. The removal rate of NH by the strain AS-1 was 1.75 mmol NH g cell−1 h−1. This strain was then identified as Pseudomonas alcaligenes (97% identity) by sequencing its 16S rDNA and comparing it with other microorganisms. Thus, strain AS-1 displays high promise for future application for in situ NH removal from piggery wastewater. [ABSTRACT FROM AUTHOR]