Biofiltration for low-carbon rural wastewater treatment: A review of advancements and opportunities towards carbon neutrality

Recently, with an increasing recognition of the global imperative for carbon neutrality, underscoring the significance of advanced sustainable and low-carbon biotechnologies for rural wastewater treatment is becoming more important. The decentralized distribution of rural wastewater, which frequently cannot be centrally processed, coupled with fluctuations in water quality and volume, present challenges for implementing low-carbon treatment strategies. Among all treatment processes of rural wastewater, biofiltration system is considered as a suitable and low-carbon treatment process. In this study, benefits and advancements of implementing biofiltration process and its derivatives as good alternatives to the low-carbon treatment of rural wastewater towards carbon neutrality. Challenges of rural wastewater treatment and limitations of existing biological treatment processes were investigated. Advanced biofiltration technologies integrated with the concept of carbon neutrality present advantages such as promoted removal performance of pollutants, energy conservation, lower operational expenses, and minimal greenhouse gas emissions were recommended. These systems have the potential for extension and modification to accommodate various circumstances. Newly developed biotechnologies for the enhancements of biofiltration process include combinations like improvements on filter media, exogenous additives for enhanced removal, integration with carbon-neutral processes for effective nitrogen and phosphorus removal like sulfur-based autotrophic denitrification, pyrite-based autotrophic denitrification and anaerobic ammonium oxidation process with its upgrades and derivatives. In the future, developments in biofiltration process can be pursued through various avenues for the aim of achieving low-carbon treatment of pollutants from rural wastewater. This study offers a novel perspective on the utilization of biofiltration and popularize the carbon-neutral treatment of rural wastewater.