Egypt faces significant challenges in managing its sewage sludge generated in large quantities from wastewater treatment plants. This study investigates the feasibility of utilizing sewage sludge as a renewable resource for hydrogen production through anaerobic digestion at the 100 L bioreactor level. Hydrogen is considered a promising alternative energy source due to its high energy content and environmental benefits. To optimize the microbial degradation process and maximize hydrogen production from sewage sludge, a specialized pretreatment is necessary. Various pretreatment methods have been applied to the sewage sludge, individually and in combination, to study the bio-hydrogen production from sewage sludge. The four methods of treatment were studied in batch assays as a pilot scale. Thermal pretreatment of sewage sludge significantly increases bio-hydrogen production yield compared to other sewage sludge pretreatment methods, producing the highest H₂ yield (6.48 LH₂/g VS). In general, the hydrogen yield of any type of pretreated inoculum was significantly higher than the untreated inoculum. At the same time, alkaline pretreatment improved the hydrogen yield (1.04 LH₂/g VS) more than acid pretreatment (0.74 LH₂/g VS), while the hydrogen yield for the combination of pretreatments (shock alkali pretreatment) was higher than both (1.73 LH₂/g VS), On the other hand, untreated sewage sludge (control) had almost no hydrogen yield (0.03 LH₂/g VS). The self-fermented anaerobic bioreactor improved sewage sludge utilization, increased bioenergy yields, and seems to be promising for treating complex wastes at this scale.

Egypt faces significant challenges in managing sewage sludge (SS), which is generated in large quantities. This study investigates the feasibility of utilizing SS as a renewable resource for biohydrogen production through anaerobic digestion (AD). As a sustainable energy source with minimal use of hydrocarbons and a high energy yield, it is a promising alternative to fossil fuels. The utilization of a specialized pretreatment technique, in conjunction with the combination of fallen Trees leaves (FL) as a carbon-rich source and SS as a substrate with high nitrogen content, demonstrates significant potential for optimizing the microbial degradation process and maximizing biohydrogen production from SS combined with FL. Four treatment conditions for the SS were used in the present experiments: control phase (CP), thermal pretreatment phase (TP), co-fermentation phase with 0.25 g of volatile solids (VS) of FL/1.0 g SS (TPFL-1), and 0.5 g of VS of FL/1.0 g SS (TPFL-2). The results proved that the hydrogen production from TP exceeds that of CP by a factor of 232. When mixing FL with SS, it can lead to efficient biohydrogen production. According to our results, the optimum mixing ratio of SS to FL was 0.5 g VS of FL/1.0 g SS, and by this ratio, biohydrogen production was higher than the other ratio by 20%. The removal of COD and VS has increased by 27% and 21%, respectively, compared to other ratios. Concisely, the deployment of the prepared FL with SS led to improved biohydrogen production and enhanced sludge treatment efficiency. Special Issue of AEIC 2024 (Civil Engineering Session)