Zaied Bin Khalid

Sustainability in terms of the economy and the environment is severely hampered by poor waste management in the industrial sectors and a lack of renewable energy sources to meet expanding energy demands. To address this issue, the influences of sodium bicarbonate treatment on biogas generation during the anaerobic fermentation of corn stalks were analyzed. The application of sodium bicarbonate (9%, w/w) resulted in a significantly higher generation of 14692 mL biogas with a production of 223 mL/g, which was 30% higher than the untreated sample biogas generation. Surprisingly, chemical oxygen demand elimination was boosted by a factor of ten. In addition, sodium bicarbonate stabilized the pH of fermented corn stalks. The Gompertz modeling, according to the findings, had a significant correlation coefficient (> 0.995) and fit the accumulative biogas production trends well. Sludge recapture from the fermented effluent was 0.08 m3 sludge/m3 wastewater. Sodium bicarbonate added to corn stalks may increased the cumulative methane production while lowering chemical oxygen demand (COD) levels.

The fundamental challenge to balancing the fuel demand is the risk of process instability. Research on energy recovery from aquaculture effluent addresses energy demands and environmental pollution concerns. The current study examined the effectiveness of anaerobic co-digestion of aquaculture effluent in a 45 L thermophilic reactor without utilising chemical catalysts. The partially digested cow manure created a substantial buffering capacity in this co-digestion process that balanced the volatile fatty acids (VFA). The methane produced was 0.45 m3 CH4/kg VS, whereas 71% of the chemical oxygen demand (COD) was removed. Thermophilic wet co-digestion was used to shorten the digestion and co-digestion phases. The results showed the highest methane was produced after 5 days (0.085 m3 CH4/(kgVSday), and 81% of total methane potential was attained after 9 days. The system proficiency for eliminating volatile solids was more than 36% after 6 days. Sludge recovery was 0.08 m3 sludge/m3 wastewater and water recovery was 0.85 (m3 sludge/m3 wastewater). It is suggested that wet co-digestion at a thermophilic state was favourable for the commercial application of co-digestion of aquaculture wastewater.

The potentials for non-stop hydrogen and methane production employing an ideal loading mixture of palm oil mill effluent (POME) and aquaculture wastewater (AWW) in a double-phase digester at a thermophilic state are presented. Different organic loadings were studied such as 31, 41, 51 and 61 Kg COD/(m3 d) for the generation of hydrogen; 9, 11, 14 and 16 kg COD/(m3 d) for the synthesis of methane. In a UASB reactor, hydrogen production was kept under control with a constant HRT of 12 h. At the loading of 51 kg COD/h, the maximal H2 content, volumetric H2 generation rate and H2 yield were observed as 46%, 6 L H2/d and 34 mL H2/g COD, respectively (m3 d). After an HRT of 6 days, the substrate from the hydrogen digester was further fermented into methane in the CSTR digester. At an organic loading rate of 14 kg COD/h, the highest volumetric CH4 generation rate and yield were 11 L CH4/d and 0.13 m3 CH4/kg COD, respectively (m3 d). This two-stage procedure removed 92% of the chemical oxygen requirement overall. Based on the findings, the Gompertz modeling was a good fit for the cumulative methane generation patterns, with a strong correlation coefficient (> 0.994). Sludge recovery was 0.07 m3 sludge/m3 wastewater and water recovery was 0.82 m3/m3 wastewater. This double-phase technique has the potential to contribute greatly to the development of a comprehensive waste management plan, including the digestion of palm oil mill effluent and aquaculture wastewater.

A unique dual-phase biological system for producing power from the potato wastes was developed. In the beginning, commercially available glucoamylase was used to hydrolyze potato wastes resulting the production of potato waste hydrolyzate. A 100 g of potato waste produced 30 g of hydrolysis solid and 750 mL of potato waste hydrolyzate. Within 6 h, the maximum glucose generation was 20 g/L while the maximum COD elimination was 85%. During the second phase, the soluble potato waste hydrolyzate was utilized to feed microbial fuel cells (MFC), which produced electricity. The maximum voltage measured was 1.1 V. When the external resistance was 1091 Ω, the power density reached its greatest point of 93 mW/m3. To evaluate MFC performance, a Coulombic efficiency of 20% was obtained, thus exploring a new field by converting the high-starch molecules into biofuels, thereby lowering the cost of commercial biofuel production.

This study looked into the possibility of using peroxydisulfate pretreatment to enhance biogas production from anaerobic fermentation of algal slurry. The results demonstrate that a peroxydisulfate added system with a dose of 0.02 g peroxydisulfate/g algal sludge TSS produces the most accumulative methane after 61 days of fermentation. At 0.02, 0.03, 0.06, 0.2, 0.3, 0.6, and 1.2 g peroxydisulfate/g algal sludge TSS cumulative methane generation was 1.16, 1.09, 1.15, 1.14, 1.09, 0.77, and 0.16 times higher than control. After 120 minutes of pre-treatment, the SCOD in the system continued to rise when the peroxydisulfate dosage was enhanced. To simulate the methane yield, a one-substrate model might be utilized. After dosing with peroxydisulfate, the hydrolysis rate reduced, and the maximum resultant and anticipated cumulative methane output was achieved with 0.02 g peroxydisulfate/g algal sludge TSS. After digestion, microcystin-LR in algae slurry was mostly eliminated. Heavy metals could be released from algae cells into the effluent as a result of the greater peroxydisulfate dosage. From the fermented effluent, sludge recapture was 0.09 m3 sludge/m3. The supplementation of peroxydisulfate to algae slurry may boost cumulative methane generation while also lowering microcystin-LR levels.