Collection and treatment of domestic wastewater: a critical review of the achieved results

Introduction. The subject of the review is systems of collection and treatment of domestic wastewater in cities, towns, and settlements (drainage systems of residential areas). The review considers both the entire systems and their constituents, i.e., the facilities of wastewater collection and transportation, wastewater treatment plants, water outfalls, etc. Research and design of effective drainage systems is an essential factor in ensuring the ecological well-being of residential areas. The tightening of standards for the discharge of treated wastewater into water bodies stimulates the development of wastewater treatment and transportation technologies not only for large cities but also for small settlements. The purpose of the review is assessing the efficiency of the technologies used in practice for wastewater collection and treatment, analyzing the relevance of research developments, and formulating promising directions of the work. Materials and methods. Publications, technical reports, software products were considered. Methods of system analysis are applied, comparative criteria of efficiency of technologies and designs were suggested. Results. A comparison was conducted between foreign and domestic experience gained in solving the main problems of domestic wastewater collection and treatment systems. Special attention was paid to the revelation of cause-and-effect relations between the upgrade of legislative acts at the state and regional levels and the development of the drainage systems. Evaluation of the ecological impact of the drainage systems on the environment was given. Conclusions. Investigations by domestic and foreign specialists in the subject were analyzed. It was revealed that there is virtually no research devoted to simulation and efficiency assessment of drainage system operation as a whole. Obviously, this is due to insufficient cooperation between research teams and designers and operators. Just this direction should be considered the most promising in the nearest future.