An investigation into the role of treatment performance and soil characteristics of soil-based wastewater treatment systems

Abstract

Soil-based onsite wastewater treatment systems (OWTS) are becoming more important for the treatment and disposal of wastewater in areas that have not central wastewater collection and treatment systems. However, there are concerns that OWTS may have adverse effects on public health and environment. The purpose of this study is to treat wastewater with using natural soil column in order to evaluate treatment system performance. Wastewater was applied to two different natural soils at different flow rates of 9, 18 and 36 L/day. The treatment performances of wastewater and geotechnical properties of the natural soils were examined. As a result of this study, the percentage of COD and SS removal in wastewater after soil column filtration were range from 36.2% to 80.5% and 84.4% to 97.9% respectively. pH values of wastewater after the filtration were measured between 7.75 and 8.12. TP and TN removal rates were found in the range of 23.9–76.8% and 12.4–83.0%, respectively. The column effluent water were classified as both ‘high hardness class’ in terms of hardness and ‘polluted water’ in terms of conductivity. Column effluent water were found in ‘low, medium, and high hazard’ classes in terms of SAR. Whereas the PL values of the natural soils were found to increase by up to 4.8% in filtration area, specific gravity decrease nearly 1.1%. The values of LL, PI, maximum dry density, optimum water content, and permeability were changed depending on the soil type. The UCS of the natural soils after wastewater filtration decreased by about 5.9%. It was concluded that natural soils have positive effects on treatment of wastewater in short time.

Eliciting Expert Judgements to Underpin Our Understanding of Faecal Indicator Organism Loss from Septic Tank Systems

“…The degree of slope on which STS are situated and their proximity to a watercourse are highly transferable environmental variables and well recognised risk factors (Tyre et al, 2023;Wiesner-Friedman et al, 2022). Although the notion of effluent movement risk, represented by HOST in our study, makes the elicited proportions more representative of the UK, these can be modified to fit classifications of soils and associated hydrological pathways outside of the UK as a generalised concept (Baykus et al, 2022;Tamang et al, 2022). While the three risk factors integrated into our combined scenarios are recognised as key drivers of FIO risk (Glendell et al, 2018), the expert judgements provide only a first approximation of the likelihood of annual FIO delivery from STS to watercourses.…”

Công nghệ xử lý nước thải chi phí thấp góp phần phát triển bền vững nguồn nước vùng Đồng bằng sông Cửu Long

“…TIỀM NĂNG Lọc đất từ lâu đã được sử dụng xử lý nước thải với chi phí thấp và loại bỏ chất dinh dưỡng hiệu quả. Theo các nghiên cứu trước đây, hệ thống lọc đất nhiều lớp (MSL: Multi-Soil-Layer) có thể loại bỏ hiệu quả nitơ, phốt pho và chất hữu cơ trong nước thải (Wakatsuki et al, 1993, Pattnaik et al, 2008, Baykuş and Karpuzcu 2021. Tuy nhiên, công nghệ này vẫn chưa được chấp nhận để xử lý nước thải ở nhiều vùng do những lo ngại đặc biệt về sự không ổn định trong việc loại bỏ vi khuẩn chỉ thị ô nhiễm phân.…”

Feasibility of Improving the Quality of Treated Wastewater Owing to Soil Improvement

“…Research has shown that soil can naturally lter out certain things like COD, SS (Suspended Solids), phosphorus, and nitrogen. Natural soils can help to clean wastewater fast (Baykuş et al, 2022). A special type of soil called multilayer soil can effectively clean dirty water.…”