This document  by the Central Pollution and Control Board (CPCB) describes the findings of a study that evaluated water treatment plants located across the country, for prevailing raw water quality, water treatment technologies, operational practices, chemical consumption and rejects management.

The report is subdivided into the following chapters:

• Introduction
• Water quality and its consumption
• Water treatment technologies
• Effects of fluoride and arsenic and removal techniques
• Operation and maintainance of water treatment plants
• Water quality control and assessment
• Results and discussion

The aims of this project were as follows:

• To study the water treatment plants for their operational status
• To explore the best feasible mechanism to ensure proper drinking water production with least possible rejects and its management.

The methodology consisted of three phases: 

• Questionnaire survey covering 202 class 1 towns
• Field studies (dry and wet studies)in 52 water treatment plants throughout the country including sample collection and analyses in 30 plants, and 
• Compilation of information

The study found that:

• Surface water is the predominant source of raw water for all water treatment plants
• Conventional treatment is provided having a sequence of alum addition, coagulation, flocculation, sedimentation, filtration and disinfection by chlorination
• The study revealed that there is no uniform or set pattern of operation and maintenance of water treatment plants
• Alum was being added as coagulant in almost all the water treatment plants
• Alum dosing equipments were found to be not working in many water treatment plants. 
• Algae growth was not significant in case of rapid sand filters. However, in case of open filters having direct sunlight, frequent cleaning of filter bed walls to remove algae is required
• Study reveals that filter backwash water and clarifier sludge of water treatment plants need to be treated before discharge
• Central Pollution Control Board developed technology for recovery and reuse of the alum used for clarification, which is under execution for viability of pilot scale.

The study suggested that:

• Sludge and filter back wash water needed to be treated and properly disposed
• Almost all the water treatment plants were using liquid chlorine for pre & post chlorination, except few, which were using bleaching powder. Use of pre chlorination could be avoided due to possibility of formation of Tri halo methane. Use of ozone, copper sulphate, potassium permanganate etc. could be explored thorough R & D activity wherever algae problem was faced or contamination of water source was suspected
• In many cases, chlorination was not found functioning at the time of visit resulting in excessive use of chlorine. This caused chlorine leakage and corrosion of water treatment plant equipment and structure, therefore, a mechanism, similar to that of the boiler inspectors was to be established to ensure proper functioning of chlorinators
• Water treatment plant operators needed regular training. Proper database of operation & maintenance of water treatment plant neede to be prepared and efficient Management Information Systems (MIS) had to be developed to cater to all the activities of water treatment plants.

A copy of the report can be downloaded from below: