Operation of water supply system is timely and daily operation of the components of a water supply system such as headworks, treatment plant, machinery and equipment, transmission mains, service reservoirs and distribution system etc. efficiently and economically to attain the objective of supplying safe and clean water equitably to the consumers.
MAINTENANCE of water supply system is defined as the art of keeping the structures, plants, machinery and equipment and other facilities in an optimum working order and proper functioning without any interruption. There are two types of maintenance viz., Preventive Maintenance and Corrective Maintenance.
PREVENTIVE MAINTENANCE constitutes routine works and precautions to be taken periodically to prevent the system from mal-functioning by mechanical adjustments, repairs, corrective action and planned maintenance.
CORRECTIVE MAINTENANCE involves carrying out works related to break down, which has actually occurred by replacements, correction of defects etc.
Preventive maintenance is more economical than corrective maintenance and it provides uninterrupted service and avoids the need for corrective maintenance.
Poor O&M practices have, on mimy occasions largely contributed to decreased utility or even to an early failure of newly constructed water supply facilities. Thus the health and social benefits for which the facilities were designed and implemented have not been realized, capital investment have been wholly or partially lost and scare resources are expended on the premature replacement of equipment or for the rehabilitation of facilities before they have been in operation for the full span of their useful lives. Hence, proper O&M is absolutely essential for deriving the benefits continuously from the investments made.
Basic requirements of successful O&M of a water supply system include:
Availability of Detailed Completion Plans and Operators’ Manuals: At least five sets of the records of Completion plans of all components, Operators’ Manuals of each machineries and equipment must be made available; one set is kept in the Head office, one set at the site offices and other sets in the sub-offices. All these sets must be corrected and pdated whenever additions or alterations are made to any of the structures and equipment in the water supply systems.
Understanding the Plant: A thorough knowledge of the plant, the processes and functions of each of equipment, operating procedures and schedules of preventive maintenance by the operators as well as the engineer-in-charge of the Water Treatment Plant, pumping station and transmission and distribution system is essential.
Schedules of Operation and Preventive maintenance: A detailed schedule of unit operations and routine preventive maintenance to be carried out daily, weekly, monthly and annually is worked out and a copy of the same is made available with each of the operators. The schedules should also be exhibited on the wall near the equipment. The schedules of unit operations may have to be altered to suit changes in raw water quality, hours of availability of power, breakdowns and up-set conditions etc. The responsibility of the specific preventive maintenance work should be assigned to each of the operators.
Schedule of Inspection of Machinery : A systematic regular schedule of inspection of machinery and equipment, their lubrication and servicing programme must be prepared and provided to the operators. Appropriate supervisory control should be exercised.
Training: The personnel who are already available or chosen to carry out the activities of O&M may have to be trained through special courses or by “on the job training” to ensure that these personnel are thoroughly trained to carry out the actions required in the plan of maintenance. This training is essential from time to time so as to keep them conversant with the latest technological advances in the field and to prevent experimentation by operating personnel to meddle with equipment since often these operating personnel may not be capable to take up the required maintenance. On the job training is preferred to class room lectures. The supervisors can be trained initially and then they can later train their operators.
With proper training the existing operation and maintenance staff can do the operation and maintenance work without any extra expense.
Staff Position: Appropriate charts indicating the operating and supervisory staff actually in position should be maintained at the WTP, pumping stations and at each office for review. The job description of operating personnel shall clearly define the limits up to which these personnel can carry out normal maintenance. The job description of the Supervisor jManager shall include the requirement that they shall ensure that the operating personnel conform to these limits and thus ensure the safety of the equipment.
Records of Equipment and Machinery: For each piece of equipment and machinery records (Log book and History book) should be maintained in which all details of the equipment and activities such as servicing, lubrication, replacement of parts, operating hours on each day and other pertinent data are recorded. The O&M plan programme contains as to what should be done and when. But to decide as to how long the equipment is to be allowed to be kept in service requires information as to when it was installed, what is its normal life etc.
Good history record system shall include the following minimum information to ensure the required maintenance.
Records of Water Quality: Complete records of physical, chemical and bacteriological analysis of water-samples collected at strategic locations at least twice in a year from source to the consumers’ taps should be maintained and reviewed. Charts could be prepared for important water quality parameters (for example turbidity, Fe residual chlorine etc.) and any changes as compared to standards must be taken note ot for taking corrective measures.
Records of Key activities of O&M: It is advisable to maintain records of certain key activities such as daily and cumulative supply of water over the years, quantity of water treated and the quantity of water supplied.
Overall Supervision and Inspection: Overall supervision and inspection of O&M activities are essential to ensure efficient functioning of all components of the water supply system.
Good Housekeeping: Buildings, other structures and equipment should be maintained in good condition. Exterior of concrete surfaces are colour washed and metallic parts are painted annually. The environment of the WTP and pump houses must be maintained clean, tidy and pleasing, by developing good garden and trees.
Operation and Maintenance Manuals
Preparation of O&M manual consisting of features of O&M of individual components of the water supply system is necessary for adopting in the O&M of the systems. The O&M features of the following components are discussed in the following subsections.