MUNICIPAL WATER SUPPLY SYSTEM
Definition of municipal: “A security issued by a state or local government or by an authority set up by such a government”.
In most developed countries in the world, water is supplied to households and industries using underground water pipes. That water is processed and treated to meet drinking water standards, even though only a very small proportion is consumed.
Sources of Tap Water
In most cities and towns, municipal water comes from large wells, lakes, rivers, or reservoirs. Most cities and towns process the water at treatment plants before the water is tested for EPA compliance and is then piped to residential homes and industries.
The amount and type of treatment applied by a public water system varies with the source type and quality. Some groundwater systems can satisfy all federal requirements without applying any treatment, while others need to add chlorine or additional treatments. Because surface water systems are exposed to and fed by direct land runoff and exposed to the atmosphere, they are more easily subjected to contamination. Federal and state regulations require that those systems treat this type of water to meet health-based standards.
Municipal water consumption
Water consumption in a community is characterized by several types of demand, including domestic, public, commercial, and industrial uses. Domestic demand includes water for drinking, cooking, washing, laundering, and other household functions. Public demand includes water for fire protection, street cleaning, and use in schools and other public buildings. Commercial and Industrial demands include water for stores, offices, hotels, laundries, restaurants, and most manufacturing plants. There is usually a wide variation in total water demand among different communities. This variation depends on population, geographic location, climate, the extent of local commercial and industrial activity, and the cost of water.
In any community, water demand varies on a seasonal, daily, and hourly basis. On a hot summer day, for example, it is not unusual for total water consumption to be as much as 200 percent of the average demand. The peak demands in residential areas usually occur in the morning and early evening hours (just before and after the normal workday). Water demands in commercial and industrial districts, though, are usually uniform during the work day. Minimum water demands typically occur in the very early or predawn morning hours. Civil and environmental engineers must carefully study each community’s water use patterns in order to design efficient pumping and distribution systems.
Water in rivers o lakes is rarely clean enough for human consumption if it is not first treated or purified. Groundwater too, often needs some level of treatment to render it potable. The primary objective of water treatment is to protect the health of the community. Potable water must, of course, be free of harmful microorganisms and chemicals, but public supplies should also be aesthetically desirable so that consumers will not be tempted to use water from another, more attractive but unprotected source. The water should be crystal clear, with almost no turbidity, and it should be free of objectionable colour, odour, and taste. For domestic supplies, water should not be corrosive, nor should it deposit troublesome amounts of scale and stains on plumbing fixtures. Industrial requirements may be even more stringent; many industries provide special treatment on their own premises (water purification plant Water purification plant in Japan. Mayuno).
The type and extent of treatment required to obtain potable water depends on the quality of the source. The better the quality, the less treatment is needed. Surface water usually needs more extensive treatment than does groundwater, because most streams, rivers, and lakes are polluted to some extent. Even in areas remote from human populations, surface water contains suspended silt, organic material, decaying vegetation, and microbes from animal wastes. Groundwater, on the other hand, is usually free of microbes and suspended solids because of natural filtration as the water moves through soil, though it often contains relatively high concentrations of dissolved minerals from its direct contact with soil and rock.
In any water supply system there is certain EPC (Engineering Procurement Engineering) activity takes place and after maintaining the water supply scheme/system for certain months or years, it is officially handover to the Operation and maintenance department. But the problem is, 90% of the water supply schemes in developing countries fail due to unequal and input-less water distribution system. I cannot help saying here, “Asset Management System” & “Operation and maintenance manual” is the fast and fore most thing to apply on any water supply scheme. And apart from the above, there must be approved checklist on “project handover Input-list”,” Commissioning Checklist” from EPC team. Because, the operation is more challenging than the EPC part. If by chance, O&M team will get inputs regarding the scheme with error database, then gradually this error will become the root-cause of the failure water supply scheme.
In India and other developing countries should concentrate on the proper sequencing of the project and operation activity. Few of the activities are never ending such as, GIS (Geographical Information System) data updating on satellite base map, TPM (Total Productive Maintenance), Pressure Zero tests, Leak detection activity, Meter Management, Bill-Demand-recovery and etc. There must be a fixed panel for the mentioned activities in each water supply schemes.
Pre-activities to rehabilitate old water supply scheme:
Example: Detailed research on the operation of the water supply system in the city of Krakow has shown that the losses amount to 13.41% at the end of 2014 with 55,48,000 m3 having been pumped into the system over the whole year. In accordance with the register, failures caused by corrosion account for approx. 20% of the overall number of water supply failures. Failures of water main networks above ϕ 300 mm account for approx. 7%. A considerable number of failures of main networks are subject to local corrosion, which leads to perforation of pipe walls.
Water Leak Detection activity is not only about detection of leaks and repair it. It is about a analysis of the major “Leak Prone pockets” of the whole WS Scheme. Though there is hardly economic condition assessment mechanism in water distribution network system, that’s why, we can easily use this leak detection activity to implement in condition assessment.
On the other hand, knowing your asset is the first and foremost responsibility of any Water Supply Manager. Because, until you know where your assets are, you will never able to maintain it efficiently. That is why, location of utilities must be mapped on GIS or similar type of mapping software as per availability. On the other hand, a consumer door-to-door survey should be conducted accordingly marking GIS id number on the properties. After these mentioned activities only, a water supply scheme should act towards rehabilitation. Because, these data are the major inputs to prepare any rehabilitation water supply project (If it is recommended to replace the whole pipe lines with assets then leak detection and utility mapping is not required before hand).
Procedures, Forms, trainings:
In order to maintain the execution as well as operation & maintenance part, there must be standard forms, approved work procedures and sufficient arrangement for training the existing staffs in any water supply schemes. Even the DPRs must have a standard format in which only the inputs are to be placed and verified by the concerned authorities.
Training of safety management, SOP, TBEM, Approvals, technical aspects etc. should be conducted routine basis in any project or maintenance phase.
Non-Revenue Water or Un-Accounted for Water in the burning issues right now in water industry and indeed it should be. But before taking any step towards reduction of NRW, the basis home work is mandatory i.e
Consumer survey report= A water supply system never should depend regarding calculation of population/property database taken from last census, rather than, taking exact data to estimate proper demand is necessary. And creation of GIS id on map and conducting Consumer Survey is also a vital exercise to do in the beginning of any project work.
Accurate population data base (Ref: Follow point number 1.)
Billing-demand-recovery data base.
Exact mapping of all over ground /underground assets.
Water metering (Bulk + Domestic) with real time monitoring mechanism- In this points, utility owners must buy updated technology benefited products which can give them real time, error free supply/consumption status integrated with IoT/SCADA.
Software based billing system.
Hydraulic zoning ** :** In case of most urban and rural water supply system municipal engineers use administrative boundaries, not hydraulic boundaries.
DMA (District Metering Area). Etc. - any distribution network model should be approved by both EPC and O&M team to identify isolation valve’s position, NRV’s location. Scope to conduct certain tests like: a) PZT, b) Step Test, c) MNF study etc.
The most low budget activity in water supply system is to conduct water saving awareness program and which is conducted by hardly any WSS. There should be hoardings, Question /answer session conducted with housewives (who actually involve behind the water consumption) in local level community halls and award them with small prizes, house hold items etc. It really works. If you don’t agree with my statement then visit Jamshedpur, Chandigarh and other private cities. On the contrary when public gets you in touch with them, there you start building relation between Utility and consumers.
There are three simple sequence to establish and manage