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Background: The aim of this study was to evaluate the biogas production of chicken manure (CM) co‐digestion with different types of household waste (soft organic [SO] and food waste [FW]), as well as to evaluate the bacterial load of feeding stock and digested slurry samples before and after anaerobic digestion (AD). The experiment was carried out using lab‐based prototype digesters for co‐digestion of CM with different household wastes (5%). Three experimental groups (T1, T2, and T3) were designed using mixing ratios of SO:CM:H2O:inoculum (5:22.5:22.5:50), FW:CM:H2O:inoculum (5:22.5:22.5:50), and (SO + FW):CM:H2O:inoculum (2.5 + 2.5:22.5:22.5:50). The digesters were set at 28–34°C for 30 days for hydraulic retention time (HRT). Total viable count (TVC), Escherichia coli, and Salmonella spp. counts were determined using the spread plate technique. Results: The study revealed that the highest average cumulative biogas yield was achieved from T1 > T3 > T2, but the concentration of CH4 was found in T3 > T2 > T1. The biogas production between the three groups was statistically nonsignificant (p > 0.05) but the daily concentration of CH4 was found statistically significant (p < 0.05). The average concentration of CH4 and CO2 in biogas was found to be 30% and 68% for T1, 60% and 37% for T2, and 69% and 27% for T3. However, the H2S content was within the acceptable range. The bacterial load was decreased by 2–3 logs before and after AD, and this reduction was statistically significant (p < 0.05). Conclusion: The research found that the co‐digestion of CM with combined household wastes increased the methane concentration in biogas. [ABSTRACT FROM AUTHOR]

Background: The focus of this research was to assess the biogas production of Chicken Manure (CM) collected from hybrid layer chickens fed non‐commercial (CMNC) and commercial (CMC) feed, as well as to evaluate the bacterial load of feeding stock and digested slurry samples before and after Anaerobic Digestion (AD). The effects of the feedstock and digestion composition of CM on biogas production were measured. The experiment was carried out utilizing lab‐based proto‐type digesters for CM with or without inoculum. For each commercial and non‐commercial feed, four experimental groups (CMNC1, CMNC2, CMC1, and CMC2) were designed using mixing ratios of CM: H2O: inoculum (25:25:50) and CM: H2O (50:50). For Hydraulic Retention Time (HRT), the digesters were set up at ambient temperature (28–34°C) for 30 days. The spread plate technique was used to determine the Total Viable Count (TVC), E. coli, and Salmonella spp. counts. Results: The highest average cumulative biogas yield was achieved from CMC2 > CMNC2 > CMC1 > CMNC1. The biogas production of inoculum added groups were statistically significant (p < 0.01) than the without inoculum groups. The average concentration of CH4 and CO2 in biogas was 49% and 51% for CMNC1, 58% and 42% for CMNC2, 46% and 54% for CMC1, 52% and 42% for CMC2. However, the H2S content was within the acceptable range except for the CMNC2 group. The bacterial load was decreased by 2–3 logs before and after AD, and this reduction was statistically significant (p < 0.05). Conclusion: The study concluded that the CM diluted with water and inoculum (25:25:50) ratio was recommended for sustainable biogas production. [ABSTRACT FROM AUTHOR]

Background: Anaerobic digestion (AD) has many benefits and is a safe way to generate energy, address the energy shortage problem, and reduce waste and carbon emissions. The study aimed to determine the performance evaluation of prefabricated polyvinyl chloride (PVC) biogas digester and compare different feeding intervals using cow manure. This study was conducted at ambient temperature in three types of feeding practice (daily, 4‐day, and 7‐day feeding interval) to investigate the variation of biogas production and evaluation of digester performances. The composition of biogas, pH, and total volatile fatty acids (TVFA) were measured regularly and weekly basis. The TVC, Escherichia coli, and Salmonella spp. counts were determined by the spread plate technique method using PCA, EMB agar, and SS agar plate, respectively. Results: The comparison results of daily versus 4‐day feeding interval indicated that the total biogas and methane yield was 34% and 28% higher in 4‐day interval feeding. The average digester performance was also 34% higher in 4‐day feeding interval digester than daily feeding digester. However, the comparison results of daily versus 7‐day interval feeding indicated that the total biogas, methane yield, and digester performance were slightly higher in daily feeding. Before and after AD, the bacterial load (TVC, E. coli, and Salmonella spp. count) was reduced by 2–3 logs, and this reduction was also statistically significant (p < 0.05). Conclusion: The performance of PVC digester was highly satisfactory and good enough to fulfil the demand (0.8–1.6 m3) of a five‐member family for cooking both in urban and rural areas of Bangladesh. [ABSTRACT FROM AUTHOR]