A Review of Effluent Water Quality Standards for Sewage and Wastewater Treatment Plants: International Comparison and Recommendations for Domestic Standard Improvements

Effluent quality standards and energy self-sufficiency in wastewater treatment have emerged as key challenges for sustainable water management and climate change response globally. Rapid industrialization and urbanization have increased wastewater discharge, leading to frequent detection of hazardous substances and pharmaceutical residues in influent waters. In response, many countries are enhancing water quality standards and adopting advanced technologies. The United States and Japan implement effluent standards and remote water quality monitoring systems that reflect regional and seasonal characteristics. Conversely, Korea classifies effluent standards into only four regions and applies uniform criteria without considering seasonal variations. Additionally, inadequate management of emerging contaminants and the relaxation of total organic carbon (TOC) standards have exacerbated algal bloom phenomena. Although treatment standards for total nitrogen (TN) and total phosphorus (TP) have been strengthened, corresponding technological advancements and infrastructure remain insufficient. Reflecting integrated eco-toxicity management systems from the United States and Germany, Korea urgently needs a system enabling quantitative assessment among Asian countries. Furthermore, implementation of energy self-sufficient wastewater treatment technologies to reduce greenhouse gas emissions and electricity consumption at treatment plants is essential, yet Korea faces issues such as insufficient infrastructure, inadequate institutional frameworks, and insufficient incentives. A comprehensive national climate and energy strategy, along with collaborative models involving local communities, is necessary. Advanced technologies, inspired by Germany’s combined heat and power (CHP) systems and Japan’s biogas utilization methods, should be introduced. Ultimately, active governmental policy and financial support are crucial for developing and commercializing microbial electrochemical systems (MES) that convert wastewater directly into energy. This study aims to provide policy and technological directions for improving Korea’s wastewater treatment system by comparing and analyzing domestic and international cases of effluent quality standards and energy self-sufficiency.