Please use this identifier to cite or link to this item: http://localhost:8081/xmlui/handle/123456789/1463
Title: STUDY OF WATER QUALITY IN RIVER BANK FILTRATION
Authors: Thakur, Aseem Kumar
Keywords: CHEMISTRY;WATER QUALITY;RIVER BANK FILTRATION;GROUNDWATER
Issue Date: 2007
Abstract: Groundwater is depleting day by day and surface water is getting contaminated by various human activities like industrialization, urbanization and population growth. Many cities and towns are situated on river banks and have favourable hydrogeologic conditions and thus, may be benefited by riverbank filtration (RBF) which, is a low cost and efficient water treatment process. During riverbank filtration, surface water is subjected to a combination of physical, chemical, and biological processes such as filtration, dilution, sorption, and biodegradation which improve the raw water quality. A research study has been carried out to assess the water qualityduringRBF at Haridwar from 2005 - 2006. Two drinking water production wells under U.J.S. were selected to monitor the quality of bank filtrate abstracted. Two monitoring wells,MW 1 and MW 2 were also installed under the EU-India River Bank Filtration Network project. Additionally, pumping tests were carried out at the investigated production wells to determine the aquifer parameters. On site field experiments were performed to determine instant parameters such as pH, dissolved oxygen, electrical conductivity, water temperature, alkalinity and turbidity on monthly basis in pre-monsoon season and every two weeks in monsoon season, respectively. Major cations and anions, and bacteriological indicator parameters were analysed in the laboratory. Results show that all parameters investigated for production well water are within permissible limits for drinking water according to WHO and BIS 10500 (1991), except coliform counts. Due to RBF the pathogenic bacteria like total coliform and fecal coliform have been removed by 99 to 99.9 %, including under low flow conditions in the adjoining canal, when the number of total coliform was 4600 - 15000 counts/100 ml of sample, and fecal coliform was 2300 - 7500 counts/100 ml of sample. The number of total coliforms in water from production wells was observed from 0-93 counts/100 ml of sample and fecal coliform 0-23 counts/100 ml of sample. Before distribution, the drinking water is disinfected using chlorine. The turbidity is reduced by up to 99.9 %. The dissolved oxygen in canal water is around 8.7 to 9.0 mg/L while in case of wells it is 0.25 to 1.9 mg/L. It might have been used during decomposition of organic compounds. Since the Ganga River and u canal gets glacier melt water it has very low amount of dissolved solids. The electrical conductivity of well water is observed always higher than the canal water, especially IW 40 has more concentration of anions and cations than IW 18, it may be due to mixing of groundwater from the other bank. The sulphate content in canal water is slightly above in comparison to the well water. Though the total dissolved solids and especially the hardness increase during RBF, they are within permissible limits. The research presented in this thesis has attempted to bridge some of the gaps in the study of water quality during river bank filtration. An extensive review of the literature was conducted to identify the gaps and relevant research issues in the area of river bank filtration. Based on the review of the literatures it was felt that the river water is contaminated and it does not meet WHO and other national drinking water standards especially with respect to bacteriological water quality. The pollutants may be physico-chemical, biological, organic and suspended particles. A model has been developed in the Hydraulics Engineering Laboratory of Department of Civil Engineering, I.I.T. Roorkee to study the clogging effects on the river bed material and it has been observed that the filtration coefficient of river bed material varies natural logarithmic times the influent concentration of the river. It has been observed that during river bank filtration some of the water quality parameters like turbidity, total coliform, fecal coliform decrease due to river bank filtration. But there are some other types of water quality parameters like alkalinity, electrical conductivity which increase after river bank filtration. Based on slow sand filtration model of Ojha and Graham (1994), the filtration coefficient of the porous bed material which is a function of influent water quality is capable to capture the variation in water quality. The models have been developed based on different water quality and these models are capable to predict the effluent water quality. A two tier model involving clogged and unclogged layer has been developed. As a special case, a one tier model developed with the unclogged bed performs well and predicts the effluent water quality parameters efficiently. Using the travel time as an important factor, different water quality parameters based on different travel times like 3.5, 7, 14, 21, 28, 32.5 and 35 days, the water quality parameter data were interpolated and a model based on travel time has been also tested. The kinetic coefficient of this model also represents a linear variation with logarithm of influent concentration.
URI: http://hdl.handle.net/123456789/1463
Other Identifiers: Ph.D
Research Supervisor/ Guide: Ojha, C. S. P.
Gurjar, B. R.
metadata.dc.type: Doctoral Thesis
Appears in Collections:DOCTORAL THESES (chemistry)

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