Turbidity Removal during a Subsurface Movement of Source Water: Case Study from Haridwar, India

Abstract

Due to an increase in deforestation and construction activities in the Himalayan region, there is an increase in sediment laden flow in many rivers, such as the Ganges, which originate from the Himalayan region. Many cities, located along these rivers, withdraw river water through abstraction wells located close to river banks and it is of growing interest to know how the sediment load increase in the source water may affect the turbidity, also a measure of sediment load, in the abstracted water. With this in mind, a study has been carried out to assess the variation of turbidity in the source water and the abstracted water at a river bank filtration site in Haridwar, located on the bank of the River Ganges and at the foothills of the Himalayas, for the period 2005–2006. It is found that the turbidity removal coefficient varies with the natural logarithm of influent concentration of the source water. A theoretical development, based on the use of the Sakthivadivel and Einstein model, is also provided to justify the removal coefficient’s logarithmic variation with the influent concentration.