Published in Water Awareness Week- 2011 Souvenir, by Oil India Ltd. Duliajan
Abhijit Kalita
Manager (E/M)
Steam Turbine & Aux.
AGBP: NEEPCO Ltd.
Bakuloni- Dibrugarh - Assam
Introduction
Water covers 70.9% of the Earth's surface, and is vital for all known forms of life. On Earth, it is found mostly in oceans and other large water bodies, with 1.6% of water below ground in aquifers and 0.001% in the air as vapor, clouds (formed of solid and liquid water particles suspended in air), and precipitation. Oceans hold 97% of surface water, glaciers and polar ice caps 2.4%, and other land surface water such as rivers, lakes and ponds 0.6%. A very small amount of the Earth's water is contained within biological bodies and manufactured products.
As a result of growth in Industrialization and population explosion with a tendency of urbanization, there is a tremendous increase in water consumption both in Industrial and domestic level, and the sources of water are not being able to meet up this demand. So the sources are depleting and the results are obvious. Already in quite a few cities particularly in developing nations, are facing severe water crisis. And the problem is more or less evident in almost all of the industrialized places.
To counter this the need of regulating, controlling use of water and reducing wastages , i.e. using the available water more efficiently, the concept of water management has come. Now, before we plan and manager our water resources, it’s required to know our water usage exactly. That is where water audit system plays its part. A comprehensive water use audit will examine the major areas in which a facility uses water, including sanitation, maintenance, mechanical systems, building processes and irrigation. For each of those areas, the water use audit will provide breakdown of the how, when and where of water use. In addition, water use audits will take into consideration the water quality. Some of the large potential savings that can be achieved is through the recycling of water and the use of rain water. Water audits can help identify potential uses and optimization of water use.
As all the life forms on Earth need water, not only the quantity, also the quality of water is also a point of concern. Because of Industrialization and unplanned use of water, the water on earth’s surface is becoming polluted at a fast rate. Presence of harmful chemicals in water causing threat to all the flora and fauna and posing a major threat to the very existence of life forms on earth.
Water audits trace water use from its point of entry into the facility/system to its discharge into the sewer. The audit also identifies and quantifies unaccountable water losses, leaks at each point of use within and around the facility.
Though water auditing is required both in domestic and Industrial sectors for efficient management of water resources, we will be concentrating on the aspects on Industrial water audit in this article.
Relevant legislation
In the face of growing freshwater scarcity, most countries of the world are taking steps to conserve their water and foster its sustainable use. Water crises range from concerns of drinking water availability and/or quality, the degradation or contamination of freshwater, and the allocation of water to different users. To meet the challenge, many countries are undergoing systemic changes to the use of freshwater and the provision of water services, thereby leading to greater commercialization of the resource as well as a restructuring of the legal, regulatory, technical and institutional frameworks for water. In India, serious concern over water pollution and control of usage has developed in the later part of the last century among the top brasses. The first instance was the Committee formed in 1962 to draw a draft enactment for prevention of water pollution. In this chapter we would highlight a few Acts and regulations prevalent in India, for control of water usage and water pollution.
A) National Water Policy -2002 : the policy advices on promotion of conservation and consciousness through education, regulation, incentives, disincentives in all the point from input to output, basically to optimize the efficiency of utilization of water , eliminate pollution and minimize water losses through recycling, re-using and treatment of effluent.
B) The Environment Protection Act and Rules-1986 : This rules specifies waste water generation standards in m3/ton of product for water intensive industries. It also specifies standard for parameters in treated waste water discharged as effluent.
C) The water Prevention & Control of Pollution Act & Rules-1974 : The objective of the Water (Prevention and Control of Pollution) Act, 1974 is to prevent and control water pollution and to maintain/restore wholesomeness of water. It establishes both a Central Pollution Control Board, and State Pollution Control Boards to monitor and enforce the regulations. The Boards composition, terms and conditions of service of members are defined in Sections 3-12. The Board advises the government on any matter concerning the prevention and control of water pollution. It coordinates the activities and provides technical assistance and guidance. This policy sets the standards and penalties for non-compliance for polluting bodies.
D) The Water Prevention & Control of Pollution Cess Act 7 Rules -1977 : This Act provides norms on consumption of water, application of Cess on water consumption of water, incentives & disincentives in application of Cess. Its also makes provision for submission of periodic return against water usage.
Methodology
Now , as an Industry, apart from the statutory obligations, it’s important to realize the importance of forming policy and its implementation for efficient management of water. Most of the modern industries have developed its own policy for preservation and efficient utilization of natural resources. The single most important factor for company to have a successful Water Management Plan is the Top Managements Commitment towards it. There are several steps of a Water Management program as given in table below, but in this chapter we will go in detail about the water audit part only.
Water audit can be done internally, or thro’ external professional agencies. There are several methods of water auditing but basically a typical water audit consists of the following steps.
Step A: Initial Data Collection
1. Analysis of historic water use
2. Data logging of current water usage
3. Understanding of process flow and water usage trends
4. Estimating potential key points
ü
Step B : Measurements at Site
ü 1. Measurements based on site & practices
ü 2. Emphasizing of key issues
Step C: Detailed water audit
1.Determination of breakdown of Water Balance
2. Data logging on major water users on various working environments
Step D: Audit report and suggestions
ü 1. Reporting details of water usages facts
ü 2. Indication of whether Statuary norms are maintained or not.
ü 3. Suggestion of scopes of improvement
Water audit is just a part of the Total Water Management program. Based on the Audit reports; it becomes the responsibility of the Management to
§ Develop a sustainable Water Management Program, involving projects and procedures to optimize efficient use of water following the principles of Reduce, Recycle and Re-use
§ Implement the Plan setting time bound objectives and distributing responsibility, while emphasizing on modern efficient technologies.
§ Continue assessment and performance evaluation on water usage, and finally
§ Compare, record and publicize reduction in water usage
Benefits of a water audit
Benefits of an audit include improved knowledge and
documentation of the distribution system including
problem and risk areas. By providing a better
understanding of what is happening to the water
after it leaves the treatment plant, the audit can
be a valuable tool to manage resources.
- According to the American Water Works Association,
water audit programs lead to reduced water losses,
financial improvement, increased knowledge of the
distribution system, more efficient use of existing
supplies, increased safety for public health and
property, improved public relations, reduced legal
liability, and reduced disruption to customers Flow Measurements during water audit
For carrying out water audit flow measurement is the key. Earlier, when these new concepts have not been implemented, flow meters are used only in the places, which are vital for plant performance. And mow quality meters were installed in non-vital areas, whose accuracy cannot be ascertained. But for water auditing, each and every water flow has to be measured with higher accuracy, and installing new meters at every point is not economical. For example in a typical thermal power plant one may only find flow meters for Boiler Feed Pump (BFP) and Condensate Extraction Pump (CEP), while the largest water intensive component is the Condenser Cooling Circuit. Similar issues exist in all other industries too. In this place the need of accurate high tech external flow meters based on ultrasound or Doppler effect arises. These meters have high accuracy up to ±2% and can be used in variety on pipe materials of different sizes. So, the flow meters should be carefully selected depending upon its nature and field of use. For open channel flows V-notch or turbine type meters can be used.
Though ultrasonic flow meters are found to be best suited for the purpose it has one limitation- it can accurately measure only full pipe flows, otherwise the accuracy is grossly reduced. To use ultrasonic flow meters in non-full pipe flow (generally atmospheric discharge lines), a raised portion can be incorporated as shown in the figure below.Zero Discharge
In the end of the 1980’s, together with increased environmental awareness within society and industry, “Zero discharge” changed from a technical description of 100% wastewater recycling to a “goal”. The principle of “zero discharge” is recycling of all industrial wastewater. This means that wastewater will be treated and used again in the process. Because of the water reuse wastewater will not be released on the sewer system or surface water. In some developed nations there are regulations which stipulated zero discharge promotion
Zero discharge has become effective in specific sectors; agriculture (water reuse for irrigation), semi-conductor and in specific geographical areas; Middle East & Asia, where water shortages have made zero disposal a necessity.
However, in this area, considering the economics of ‘Zero Discharge’ Programs, it’s not yet possible to implement it fully. However ,most of the Industries are known to be working of reducing effluent by re-using and recycling, to achieve a goal of ‘Zero Discharge’.
Conclusion
When water systems are reaching capacity limits of water availability and/or treatment infrastructure, both public and private sectors have important roles to play. Comprehensive water management programs must address leaks and “unaccounted-for” water use, water shortage planning and water efficiency improvements, as well as implement customer education programs and conservation-oriented billing structures. Government buildings and publicly-owned facilities should serve as role models for water use efficiency in the community
Many facility managers may view water conservation measures as actions necessary only
During the period of shortages, but as discussed above, there are many important reasons to continually improve water use efficiency. Driving factors include: preservation of the quality of surface and ground water supplies; cost avoidance of water and wastewater treatment by reductions in chemical usage and energy consumed; and meeting increased future demands without increased overall water use, thus delaying the need for development of infrastructure for new raw water supplies and treatment facilities.
Though we have been talking about responsibilities of individual Companies / organizations , Water Management is basically a community issue, so contribution from everyone both in the domestic as well as industrial sector is required . Therefore, Co-ordination of all individual water management plans with involvement of statutory bodies, the Government and International Agencies is of prime importance if we desire to conserve this greatest gift of God to mankind in a sustainable manner.
Acknowledgement:
While preparing the paper help from several internet sites are taken, and thankfully acknowledge it. The author is also grateful to Mr. T. Ali, Safety Officer – AGBP; NEEPCO for providing vital information on water related legislations.
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