Advancing wastewater management and resource recovery through mainstream liquid anaerobic co-digestion of wastewater and organic waste

Abstract

The management of wastewater (WW) and organic waste (OW) has emerged as a critical environmental concern, particularly in developing countries where the disposal of these waste streams continues to represent a significant global environmental challenge. Consequently, Liquid Anaerobic Co-Digestion (L-AcoD), an innovative process which involves the treatment of OW along with WW influent flow in anaerobic-based wastewater treatment plants (WWTPs), has emerged as a promising solution, enhancing methane (CH₄) production and optimising energy recovery. This study aimed to evaluate the feasibility of L-AcoD in increasing CH₄ yields, reducing emissions, and advancing energy self-sufficiency in anaerobic-based WWTPs. The experimental design was carried out to included two biochemical methane potential (BMP) tests, examining the effect of different WW:OW ratios (98:2, 97:3, 96:4 v/v) on methane yield. The first experiment was conducted at 35 °C, while the second was conducted at room temperature (RT: 23.25 ± 0.592 °C). The key findings indicate that L-AcoD can significantly divert OW to WWTPs, resulting in an average CH₄ yield that was up to 52 times higher than that from WW mono-digestion. In addition, the biodegradability of the waste was improved, and the energy self-sufficiency of the system was enhanced, with the potential to yield 22 kWh m⁻³ for each cubic meter at RT.