This conceptual design project was prepared for a client wanting to develop a new site in rural Bihar, an Indian state south of the eastern half of Nepal which is known for its poverty and poor education level.
The site conditions, size, and location near a major river made it unsuitable for typical wastewater disposal methods, especially with the high demand of the institutional facilities proposed for the development project. The locally accepted practice of disposing of wastewater (both grey-water and black-water) by discharge into an open public channel on the edge of a street was not an acceptable option to the client, who was open to considering an engineered system from eMi2. To meet this need, a basic sand filter and chlorination system has been designed for a Bihari facilities maintenance person to manage.
This special construction is required for the treatment of effluent from the septic system mainly due to poor soils and their inability to percolate the sewage demand, as well as a high ground water table at the site area. Septic tanks serving buildings throughout the development feed liquid effluent into pipes which lead to a dosing chamber. From this chamber, a certain quantity of effluent is 'dosed' periodically into a network of perforated pipes in an engineered sand filter. After filtration through the sand, the effluent flows past chlorine contacts and is then made to ‘rest' in a tank series before being discharged outside the property wall into a public drainage channel that eventually leads to the river.
The design of this system is aimed at providing a basic level of functional treatment to improve the condition of wastewater discharge from the site, while keeping the improvement within the client's values for cost, complexity, longevity, and management.