Efficient water management needs to take a center stage in business planning by the corporates. The contemporary approach of typical ‘end-of-pipe’ treatment of industrial wastewater need to shift towards decentralized, process integrated water management with efforts towards ‘zero discharge’ or ‘positive water balance’, thus reducing the fresh water consumption as well as pollution. This requires comprehensive information about the quantity and quality of water being used (and/or wasted) at different stages of the industrial processes. The first step towards this is the identification and measurement of the flows, water quality, and losses within different stages of the system through regular water audits.
Water audit helps in development of an integrated industrial water management strategy, which optimizes efficient use of water, improves water productivity, reduces losses and helps in identifying alternative methods of water conservation such as recycling and reuse of wastewater for various process and non-process uses, rain water harvesting & groundwater recharge. The activities ensure co-benefits in energy saving, treatment costs, water quality improvement etc.
Water auditing is a method of identifying the gaps for water management and quantifying water flows and quality in simple or complex systems, with a view to reducing water usage and often saving money on otherwise unnecessary water use.
Water audit determines the amount of water lost from a distribution system due to leakage and other reasons such as theft, unauthorized or illegal withdrawals from the systems and the cost of such losses to the utility. Water Audit is a qualitative and quantitative analysis of water consumption to identify means of Reducing, Reusing and Recycling of water.
Comprehensive water audit gives a detailed profile of the distribution system and water users, thereby facilitating easier and effective management of the resources with improved reliability. It helps in correct diagnosis of the problems faced in order to suggest optimum solutions.
It is also an effective tool for realistic understanding and assessment of the present performance level and efficiency of the service and the adaptability of the system for future expansion & rectification of faults during modernization. Elements of water audit include a record of the amount of water produced (total water supply), water delivered to metered users, water delivered to unmetered users, water loss and suggested measures to address water loss (through leakages and other unaccounted for water losses).
Steps of Water Audit
· Water Supply and Utilization Study
· Process Study
· System Audit
· Discharge Study
· Water Audit Report
1. Water Supply and Usage Study
Water audit comprises of review of layout of water sources, distribution network, and service/delivery points to water users and return flow of waste or excess water. Audit shall cover the study of locations and capacities of flow measurement devices installed at key points, dimensions of pipes and fittings in the water supply system, locations and particulars of flow control devices and history sheets of all measuring and control devices including pipes and fittings. A study of the availability of water sources and past consumption patterns for various sectors is necessary to understand the present water utilization and projecting future requirement. Data on development of sustainable source of water through rainwater harvesting and effluent recycling should also be taken into consideration.
2. Process Study
Flow measurement devices may be installed at all strategic points so that water losses from various components such as raw water source, conveyance system from raw water source to user points to treatment plant, from treatment plant to treated water storage system, treated water storage system to distribution networks, individual users, etc. could be assessed at regular intervals. Such studies will also prove useful information for future extension, renovation and modernization of the system. Water quality of the distribution system needs to be monitored regularly at strategic points to find out the level and nature of contaminants present in the supplied water. Depending on the types of application and degree of purity needed, the treatment system can be designed and developed. The water distribution system, leakage assessment etc. will form an integral part of this study.
3. System Audit
The current water usages and systems for water use under various area such as Utilities, Cooling Towers, Washing and Cleaning, Electro dialysis, Laboratory area, Canteen, Irrigation and others need to be studied to check their operational efficiency and level of maintenance. The scope for any modification or up-gradation will depend on the status of existing systems. Measurement methodology from the intake point of the system through various sub-systems to the ultimate user points needs to be verified periodically for its suitability, efficiency and accuracy. Bulk metering should be done at the source for and revenue metering for consumers. This will help in identifying the reaches of undue wastewater generation.
4. Discharge Analysis
The domestic wastewater, return flows from consumption point, and effluent need to be studied for conformity to environment standards and studying the possibility of recycling of waste water.
5. Water Audit Report
Adequate planning and standard procedures are necessary prior to undertaking the water audit of a system. A water audit can be accomplished on the basis of water allotted for a service and water actually utilized for that service. After assessing the loss of water and the efficiency of the system, steps needed for utilization of recoverable water loss may be listed. A cost-benefit study for optimum recovery of water loss may be performed. A water audit report may, invariably, contain:
(a) Amount of water earmarked/made available to the service.
(b) Amount of water utilized both through metered and unmetered supplies.
(c) Water loss and efficiency of the system along with reasons for such water losses.
(d) Suggested measures to check water loss and improve efficiency.
An effective water audit report may be purposeful in detection of leak in distribution system, taking timely action for plugging such leaks and thereby reducing conveyance losses of water and improving efficiency of the system. Water audit of the system should be undertaken at regular interval of time, at least on an annual basis.
Benefits of Water Audit
Water audit improves the knowledge and documentation of the distribution system, problem and risk areas and a better understanding of what is happening to the water after it leaves the source point. Leak detection programs help in minimizing leakages and tackling small problems before they become major ones.
These programs lead to
1. Reduced water losses,
2. Improved financial performance,
3. Improved reliability of supply system,
4. Enhanced knowledge of the distribution system,
5. Efficient use of existing supplies,
6. Better safeguard to public health and property,
7. Improved public relations,
8. Reduced legal liability, and
9. Reduced disruption, thereby improving level of service to customers.
Scope of Work - Water Audit
Study the present Water Distribution System.
· Identify the sources of water supply
· Identify and compilation of the major areas of water consumption
· Evaluate the Water requirement for present facility including all services like RO, Electro dialysis, Chiller Plant, CSSD, Toilet, Laboratory, Kitchen etc.
· Estimation of the Quantity of water utilization both through metered and unmetered supplies
· Evaluate the segregation of the Industrial water from domestic water and to estimate the type of treatment required for industrial water
· Explore and identity the leakages and water loss areas
· Check the water quality/sampling in various sections of RO, drinking water, STP and water used in toilets & other relevant areas
· Check the efficiency and adequacy of Sewage Treatment Plant including tertiary treatment Plant for recycling the STP water for Gardening and to achieve Zero Discharge Status as far as possible
· Exploring the energy Consumption option through Water Conservation
· Study the rain water harvesting wells and enhance the capacity of same
· Evaluating the performance of Reverse Osmosis Plant and Softener Plant
· Water Pumping System
· Review of Fire Fighting system with respect to water conservation aspect
· Review of water pumping storage and distribution systems
· Review performance assessment of all major water pumps i.e. power consumption vs. flow delivered, estimation of pump efficiency etc.
· Exploring the Energy Conservation Options in Water Pumping System.
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