Water Resources Research Act Program

Details for Project ID 2015ND295B

Evaluation of Onsite Wastewater Treatment Systems Sand Filters and Biological Treatment on Indian Reservations

Institute: North Dakota
Year Established: 2015 Start Date: 2015-03-01 End Date: 2016-02-29
Total Federal Funds: $4,800 Total Non-Federal Funds: $9,600

Principal Investigators: Wei Lin

Project Summary: For many of the rural areas of the United States, the common practice of treating wastewater at an individual home is by the use of a septic tank and drain field. A septic tank allows separation of solids from wastewater over a period of time. The solids settle to the bottom of the tank and the liquids are travel to the next stage in the process for further treatment. Typically the next stage in the process is to use a series of leaching chambers in trenches to create a drain field, which allows the soil under the leaching chambers to act as a biological filter to further remove or eliminating contaminates and organic solids in the septic tank effluent, before reaching the groundwater.The Indian Health Services (IHS) provides design and installation of onsite wastewater treatment system for many rural homes on the Indian Reservations. When a site has low permeability, high groundwater level, or limited space for a typical septic tank and drain field system, alternative methods for treating and discharging septic effluent has to be considered. Unlike a drain field, sand filters and individual biological treatment units on the reservations use surface discharge piping to carry effluent to a ditch or slough for the ending process.However, it is suspected that many existing on-site treatment systems on Indian reservations in North Dakota and South Dakota failed to meet treatment goals due to lack of proper air circulations and in some cases overloading the systems. objectives of this study include: 1. Installation, operation and monitoring of alternative wastewater treatment systems at sites identified by IHS; 2. Collection and analysis of water samples from these alternative systems, and an existing septic/sand filter system, to evaluate their performances in terms of oxygen transfer efficiency and effluent water quality; and 3. Developing and conducting a comprehensive analysis of the systems studied to evaluate their technical merits, engineering feasibilities, and socio-economic factors, and provide recommendations to IHS for future system selection and engineering design. Results from this study will benefit IHS on selection of proper on-site treatment technologies, for application with anticipated wide range of operational conditions. It also will benefit engineers for using proper design parameters on new on-site treatment system designs and retrofitting existing systems that experience operation difficulties. The results from this research may also be applied to rural systems in other communities.