Surat Municipal Corporation (SMC) has developed a well-established networked water supply system to provide drinking water, with a consumer base of 3.25 lakhs in the geographical city limit of 334 sq km. There are ten major water distribution stations and four pumping stations responsible for the effective treated water distribution in the various parts of the city. All water works, water distribution stations and pumping stations are connected with GRID network, which connects them in such a way that in case of any abnormality or shut-down of any water works, water can be drawn from the other water works or distribution stations and demand can be met. The water supply system has a network of more than 2,550 km. Currently, SMC is supplying water of more than 680 million litres per day (mld) against the installed capacity of 828 mld.

A conventional coagulant (alum) is being used for the water treatment process. Since alum is a low-cost chemical with simple manufacturing procedures, it was easily available in the market but it was difficult to obtain quality alum (grade 1) in the market to meet the quality standards in accordance with the IS 299. Based on the information and data generated from field and laboratory trails, it was decided by the hydraulic department to use poly aluminum chloride (PAC) instead of conventional alum for effective water treatment process and better water quality at each stage of the treatment process.
Since PAC is not included in Indian Standards upto 2003-04, it was necessary to get all the information about the effects of using PAC in treatment process. A literature survey has found that a number of Indian urban local bodies and water boards and European water supply bodies are using PAC for water treatment. A major private manufacturer of PAC has been approached for conducting laboratory as well as field trails. Based on the results of trials and realised benefits, the hydraulic department has taken a decision to switch over from alum to PAC on a pilot basis with one treatment plant. The private manufacturer has been awarded the contract for providing PAC. The hydraulic department was trying to find a government manufacturer to provide PAC to avoid corruption threats in dealing with private manufacturers. It succeeded in its efforts and found one large government supplier (based in Gujarat), which was asked to prepare a report to establish effectiveness of PAC through laboratory and field trials. The government supplier has been ordered to provide PAC on a commercial offer on an annual rate contract.
The quality of the treated water has improved, as PAC is an effective replacement of conventional coagulants for the removal of microscopic suspended matters, algae, etc., on different rage of turbidity, temperature and pH levels.

SMC was able to procure PAC at reasonable rates because of the annual rate contract and the provision of the required quantity was assured within the time limit. The quality of the supplied material was ensured as it was provided by a government supplier and it goes through various quality testing. The supplier also provided the necessary technical assistance to SMC for optimisation of consumption and better quality control.
The observed performance and benefits gave confidence to SMC to institutionalise the process. SMC is following the same practices in its upcoming and proposed WTPs.

Based on the results achieved by SMC, the Government of Gujarat had made a resolution for the replacement of the conventional coagulant with PAC, that was circulated amongst the various urban local bodies in Gujarat.

SMC has shared its experience with various urban local bodies, and they showed interest in replicating the initiative as per their requirement.