In recent years, due to stringent emission regulations, vehicle manufacturers have been compelled to cut down noxious pollutants released from diesel engines. Different alternative solutions have been recommended to achieve this challenging task. One of these alternative solutions is the utilization of biogas in addition to the use of liquid diesel. In this regard, the current study investigates the combustion characteristics and exhaust emissions of a turbocharged, direct injection, diesel engine operating at constant speed (1800 rpm) and under dual-fuel mode with diesel as the pilot fuel and biogas (generated from pig manure and corn straw) enriched by various H₂ percentages (5-20% by vol.). The impacts of hydrogen addition in biogas on combustion and pollutant emissions were investigated and compared with those of biogas-diesel dual-fuel operation. Numerical simulations were carried out at two different engine loads corresponding to brake mean effective pressure (BMEP) of 0.425 and 1.7MPa. The findings revealed that Hydrogen addition in biogas resulted in a substantial rise in heat release rate (HRR) and pressure peak due to the rapid combustion during the premixed combustion stage, as compared to biogas-diesel fuel operation. The peak pressure and maximum HRR occurred earlier than that of biogas-diesel fuel operation. Concerning the emissions, the results indicated that CO₂ emissions were found to be lower for the hydrogen-enriched biogas (HEBG) as compared to biogas-diesel fuel operation at all engine loads. Significant reductions in CO₂ emissions of up to 56% were observed with 20% of H₂ in biogas. However, the addition of hydrogen in biogas increased NOx, CO, and hydrocarbon emissions. NOx emissions increased when the percentage of H₂ was increased in biogas.

In recent years, due to stringent emission regulations vehicle manufacturers have been compelled to cut down noxious pollutants released from diesel engines. Different alternative solutions have been recommended to achieve this challenging task. One of these alternative solutions is the utilization of biogas in addition to the use of liquid diesel. In this regard, the current study investigates the combustion characteristics and exhaust emissions of a turbocharged, direct injection, diesel engine operating at constant speed (1800 rpm) and under dual fuel mode with diesel as the pilot fuel and biogas (generated from pig manure and corn straw) and methane enriched biogas. Simulations were carried out at four various engine loads corresponding to brake mean effective pressure (BMEP) of 0.425, 0.85, 1.275, and 1.7 MPa using GT-Power package. The BTE values of biogas-diesel were higher as compared to diesel fuel. The CO₂ ratio of biogas did not impact BTE considerably. The highest BTE value of 38.22% was recorded for BG45. However, the Brake specific fuel consumption (BSFC) values for the biogas-diesel fuels were higher than that of diesel fuel operations. With respect to emissions, compared to diesel fuel operation, the hydrocarbon (HC) and CO₂ of the biogas-diesel were higher, but NOx and CO pollutants were much lower. The utilization of biogas with diesel by all accounts is attractive to cut down discharges and improve performance of the engine. The engine performance did not deteriorate with up to 45% CO₂ proportion in biogas.

The excessive use of antibiotics in the pig breeding industry leads to the accumulation of antibiotic residuals in the environment, which is attributed to the improper treatment of livestock excrements. Sulfamethoxazole (SMX) and Norfloxacin (NOR) are antibiotics used in pig breeding and veterinary medicines as growth promoters and antibacterial drugs. The aim of this study was to examine the effects of these antibiotics and thermophilic pre-treatment on methane (CH₄) yield by anaerobic co-digestion (AcoD) of pig manure and corn straw under mesophilic temperature condition (35 ± 1 °C). We used antibiotics at a concentration of 0, 20 and 60 mg L⁻¹ (three stages) in two lab-scale continuously stirred tank reactors. The first reactor was run using untreated fed and the second reactor was run with thermophilic (55 ± 1 °C) pre-treated fed. The results showed that the CH₄ productions from reactor one were 205, 163 and 128 and from reactor two were 222, 185 and 173 mL CH₄ g⁻¹ VS_added, respectively. This elucidates that the presence of antibiotics had a negative effect on CH₄ production. Moreover, thermophilic pre-treatment improved the performance of the anaerobic digestion and CH₄ production.