Challenges and prospects for the anaerobic treatment of chemical-industrial organic wastewater: A review

Anaerobic digestion, an economic and energy-efficient biological process, is extensively applied in the treatment of a variety of wastewater streams and organic wastes. However, the ineffective mineralization of degradation-resistant organic wastes is considered a limiting factor for this promising technology, and has prevented it from being widely adopted for the anaerobic treatment of chemical-industrial organic wastewater. In this work, the advantages and benefits of anaerobic digestion and those conventional physical/chemical/biological methods are compared. This review also suggests the current challenges and barriers to the application of anaerobic digestion to the treatment of chemical-industrial organic wastewater by considering some typical degradation-resistant organic wastes as examples. Design improvements are required to enhance the degradation from refractory organics to fermentable organics. The applications of the up-flow anaerobic sludge blanket, anaerobic membrane bioreactor and their derivatives are highly recommended in the anaerobic treatment of chemical-industrial organic wastewater. While some state-of-the-art physical/chemical technologies have been widely reported and are currently applied in anaerobic treatment of chemical-industrial organic wastewater, high energy consumption and low efficiency of these processes is an obstacle to their smooth operation and presents clear difficulties. Therefore, this work provides some perspectives for future applications and practical advice for improving and enhancing the hydrolysis step of those degradation-resistant organic wastes. Synergistic processes, such as the co-culturing method, co-digestion and nitrate-reducing anaerobic digestion are suggested as a means to achieve the effective anaerobic treatment of chemical-industrial organic wastewater and sustainable regeneration of cleaner production.