Recovery of Copper and Zinc from Livestock Bio-Sludge with An Environmentally Friendly Organic Acid Extraction.

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.

Evaluation of Water Scarcity Footprint for Taiwanese Dairy Farming.

Raw milk production in Taiwan has increased year after year, which means that the environmental impact might also be intensified in certain regions. To balance both consumer demand and environmental sustainability, evaluating the potential impact and understanding the causal relationship between production and environment is imperative. This study applied the life cycle assessment (LCA) protocol to explore water consumption for raw milk production from cradle to farm gate of five dairy farms in Hsinchu County and evaluate the stress-weighted water scarcity footprint (WSF) as well as the water scarcity productivity (WSP) of the 16 Taiwanese counties and cities. Results indicated that the highest stress-weighted WSF of the dairy farms for raw milk production was located in northern and central Taiwan and was around 44.8 H2Oeq/kg fat- and protein-corrected milk (FPCM). On the other hand, both the smallest stress-weighted WSF (about 2.2 H2Oeq/kg FPCM) and the highest WSP (0.749 kg FPCM/m3 water) of the dairy farms were located in Nantou and Chiayi Counties, because these two counties were the least water-stressed regions in Taiwan. The achievement of this study could be the first and important reference for the sustainable production of raw milk and optimizing the industrial policy of dairy farming by policy makers.

Biodiesel Production by Acid Methanolysis of Slaughterhouse Sludge Cake.

Biosludge is a normal form of accumulating microbial populations inside the sewage or wastewater treatment facilities. Excessive sludge in the wastewater treatment basins has to be removed periodically to ensure good water quality of the effluent. This study aims to evaluate the feasibility of biodiesel production by transesterification of slaughterhouse sludge cake. The sludge cake was collected from a selected commercial slaughterhouse and transesterified with methanol, n-hexane, and acids (e.g., sulfuric acid or hydrochloric acid) at 55 °C. Three acid concentrations (2%, 4%, and 8%, v/v) in methanol under four reaction time periods (4, 8, 16, and 24 h) were applied. Results showed that the highest accumulated fatty acid methyl ester (FAME) yields of 2.51 ± 0.08% and 2.27 ± 0.09% were achieved when 8% (v/v) of H2SO4 or HCl were added in a 4 h reaction time, respectively. Methyl esters of palmitic acid (C16:0), palmitoleic acid (C16:1), stearic acid (C18:0), and oleic acid (C18:1n9c) were the major components of biodiesel from acid methanolysis of slaughterhouse sludge cake. Experimental and analytical results of acid methanolysis of slaughterhouse sludge cake showed that acid methanolysis of sludge cake was one of the feasible and practical options to recycle sludge waste and produce renewable energy.

Biogas Production by Anaerobic Co-Digestion of Dairy Wastewater with the Crude Glycerol from Slaughterhouse Sludge Cake Transesterification.

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.

Treatment of duck house wastewater by a pilot-scale sequencing batch reactor system for sustainable duck production.

The objective of this study is trying to solve water pollution problems related to duck house wastewater by developing a novel duck house wastewater treatment technology. A pilot-scale sequencing batch reactor (SBR) system using different hydraulic retention times (HRTs) for treating duck house wastewater was developed and applied in this study. Experimental results showed that removal efficiency of chemical oxygen demand in untreated duck house wastewater was 98.4, 98.4, 87.8, and 72.5% for the different HRTs of 5, 3, 1, and 0.5 d, respectively. In addition, removal efficiency of biochemical oxygen demand in untreated duck house wastewater was 99.6, 99.3, 90.4, and 58.0%, respectively. The pilot-scale SBR system was effective and deemed capable to be applied to treat duck house wastewater. It is feasible to apply an automatic SBR system on site based on the previous case study of the farm-scale automatic SBR systems for piggery wastewater treatment.

Monitoring of sulfur dioxide emission resulting from biogas utilization on commercial pig farms in Taiwan.

The objective of this work tends to promote methane content in biogas and evaluate sulfur dioxide emission from direct biogas combustion without desulfurization. Analytical results of biogas combustion showed that combustion of un-desulfurized biogas exhausted more than 92% of SO2 (P < 0.01). In the meantime, more than 90% of hydrogen sulfide was removed during the combustion process using un-desulfurized biogas (P < 0.01). Those disappeared hydrogen sulfide may deposit on the surfaces of power generator's engines or burner heads of boilers. Some of them (4.6-9.1% of H2S) were converted to SO2 in exhaust gas. Considering the impacts to human health and living environment, it is better to desulfurize biogas before any applications.

Ammonium reduction from piggery wastewater using immobilized ammonium-reducing bacteria with a full-scale sequencing batch reactor on farm.

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.

Characterization of polyhydroxyalkanoate-producing bacteria isolated from sludge of commercial pig farms for producing methyl esters.

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.

Development of online sampling and matrix reduction technique coupled liquid chromatography/ion trap mass spectrometry for determination maduramicin in chicken meat.

An online sampling and matrix reduction technique coupled liquid chromatography electrospray-ion-trap mass spectrometry was developed for rapid analysis of maduramicin (MAD) residue in chicken meat. Multiple-reaction monitoring of mass spectrometry in positive ion mode was used to detect maduramicin. A post-column continuous infusion of internal standard (nigericin) with matrix-matched calibration method was utilised for quantification. The linear concentration range of the calibration curve was 0-10.0 ng mL(-1) (r(2)=0.999). The limit of detection (quantification) was 0.08 ng g(-1) (0.28 ng g(-1)). The analytical accuracy of chicken meat samples for four spiked MAD concentrations (0.5, 1.0, 5.0, and 10.0 ng g(-1)) was 84-97% and their corresponding intra-day and inter-day precisions were 3.7-5.0% and 5.8-7.9%, respectively. The analysis time for one sample was 10 min. The application of the method for incurred chicken samples elucidates that MAD residue in chicken meat decreases during the withdrawal period.

A strain of Pseudomonas sp. isolated from piggery wastewater treatment systems with heterotrophic nitrification capability in Taiwan.

A high concentration of NH(4) (+) 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 degrees 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(4) (+) was removed by 58 hours, and, eventually, 1.5 +/- 0.5 mmol L(-1) N(2) and 0.2 +/- 0.0 mmol L(-1) N(2)O were produced. The removal rate of NH(4) (+) by the strain AS-1 was 1.75 mmol NH(4) (+) 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(4) (+) removal from piggery wastewater.

Reduction of greenhouse gases from anaerobic piggery wastewater treatment by bromochloromethane in Taiwan.

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 (< or =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.

Microbial indicators for differentiation of human- and pig-sourced fecal pollution.

Microbial indicators, the ratio of fecal coliforms (FC) to fecal streptococci (FS) and a newly defined enterococcus ratio, were used to differentiate pollution sources. FC FS values for municipal sewage were significantly higher than those values of the effluent from piggery wastewater. Enterococcus ratio, the ratio of (Enterococcus durans + E. hirae) to (Enterococcus faecalis + E. faecium), of human-sourced wastewater (0.90) was much lower than for pig-sourced wastewater (5.55). When FC/FS and enterococcus ratio were applied to a contaminated river study, both were corresponded well with the population density distribution of humans and pigs. FC/FS and enterococcus ratio are feasible microbial indicators for human- and pig-sourced wastewater pollution identification in field study.