Biohydrogen production from spent wastewater treatment Substrates: Techno-Economic viability and sustainability

This critical review highlights the potential of utilizing spent wastewater treatment substrates for biohydrogen (bioH2) production, offering an eco-friendly and cost-effective solution aligned with Sustainable Development Goals (SDG 7) by promoting renewable energy production. Spent wastewater substrates are excellent feedstock due to their high organic and nutrient content, facilitating efficient waste-to-energy conversion. A hypothetical techno-economic analysis demonstrates financial viability, with key metrics such as a favorable return on investment and promising net present value, driven by low operational costs and substantial revenue from bioH2 sales. Additionally, reusing the bioH2-generated digestate as a biofertilizer and the treated wastewater for agricultural or industrial applications enhances sustainability and economic benefits. Integrating advanced pretreatment technologies, microbial consortia and carbon credit incentives can further enhance process efficiency and economic sustainability. Addressing challenges like low bioH2 yield, production of inhibitors, and scalability barriers requires targeted research, pilot scale validation and supportive policies. Scaling up pilot projects and strengthening public-private partnerships are crucial for commercialization, paving the way for sustainable bioH2 production from wastewater and advancing global renewable energy goals.