That sinking feeling
That sinking feeling
The human body is 80-odd per cent water, a few per cent bone and gristle -- and the rest, neurosis. beings are highly dependent on water for their bodily, agricultural, domestic and industrial needs. But the ubiquitousness of water has detracted from its worth -- it is a human failing that what is easily available is taken for granted.
Humans have been and still are using water as if the life-giving liquid were self-cleansing and water-bodies and aquifers bottomless. However, it has been a painful and slow realisation that the invaluable natural resource can be and should be better managed if it is to remain an easily available commodity.
Water is a prime utility service required for industry. According to the Bureau of Industrial Costs and Prices (BICP) in India, industry accounted for 6 per cent of the total water demand of all sectors of the economy in 1990. Even though the industrial requirement of water is small, there are reports of some units being shut down because of paucity of water. This is because underpricing of water and lack of awareness for water conservation have served to promote wasteful use of this resource. Water is currently supplied at highly subsidised rates. Costs such as laying of canals and dams (and the environmental costs of clearing forests for reservoirs) and their upkeep are not included in the price at which water is made available.
A water management strategy for industry is essential for its own well-being and becomes particularly important when one considers that the industrial requirement of water is poised to double by 2000 AD and become eightfold by 2025 AD. Besides, the discharge of industrial effluents is an issue that has implications for the entire society and is reason enough to implement proper water management in industry.
Unless immediate steps are taken to price water to reflect its real cost (costs incurred on storage, supply and treatment to rid water of any pollutants), minimise water demand through conservation and recycling and ensure zero pollution/discharge by industry, a water crisis would be inevitable.
Industrial thirst Water is used in industries for various purposes such as processing, cooling, washing and as boiler feed. Most of these uses are non-consumptive and so allow the water to be recycled with or without treatment -- depending on the use -- after recovery.
For a water management strategy to be effective, it should be based upon the water audit for the industrial unit concerned. The BICP of the Union ministry of industry has conducted studies on the water audit of some water-intensive industries in India. These studies also analyse the characteristics of water discharged, measures required to reduce demand and pollution and the policy initiatives required to ensure water conservation.
An important issue that emerges from the BICP"s studies conducted from 1987 to 1994 is the poor quality of water measurement systems available in Indian industry. Proper water measurement systems supported by reliable instrumentation are essential for an accurate assessment of water quantity and quality at inlets and outlets of various process units in a plant -- a prerequisite for efficient water usage.
However, this area appears to be largely neglected in most of the plants. Even where certain measurement infrastructure exists, attention is not given to its upkeep with the result that the data required for monitoring water usage is usually not available.
For example, in the case of both the Bhilai and the Bokaro steel plants, water measurement was done only at the intake (supply end of the plant) and water consumption at various unit levels were estimated. In contrast, the Vishakapatnam steel plant -- the country"s latest steel plant -- is equipped with proper instruments and measurement systems, and this has resulted in efficient water usage and effective effluent control there. Guzzle puzzle
The BICP studies revealed an apparently puzzling aspect of water consumption in industrial units. The studies show that in similar industrial units that use similar technology and product mix, the specific water consumption (water consumption per unit of the product) varies over a wide range.
For instance, in the case of paper and pulp industry, the consumption per tonne of paper varied in different plants from 230 Cu m to 450 Cu m (during 87-88) and in the fertiliser industry, water consumption in 9 plants studied varied from 9 to 40 Cu m per tonne of urea produced (during 88-89).
The wide variation in the specific consumption of water among plants in the same industry and adopting the same technology could be attributed to the differences in efficiency of operation, which depends upon how effective the water measurement system is and on the implementation of water monitoring and conservation measures.
Other factors that may influence the water consumed by an individual plant include: the type of raw-materials/feedstock used, the type of water storage in plant (earthen/concrete), transportation mode (open canal/pipeline) and cooling arrangement for process water (cold water/hot water system).
But, whatever the reasons, water intake of Indian industries is considerably greater than that of their counterparts in developed countries (Table-1). There may be differences in operating conditions: the Indian plants might be smaller and using outdated technologies as compared to their foreign counterparts. All the same, the fact that even the lowest water consumption figures of the Indian plants are significantly higher than the international levels in most cases shows the Indian industry in a poor light.
The BICP studies also stress upon the need for a qualitative humanpower mix in different areas of water management in an industrial unit to make the conservation strategy effective. Normally, the plant managements focus is on the main function of production of the concerned goods. What is ignored is the integration of various water management units such as water procuring group, inplant water supply group, environment group comprising of scientists and technicians and the continuous skill upgradation of these personnel.
What are the specific problems that ail the different categories of industries? The BICP studies take a close look at 3 types of water-guzzling industries: paper and pulp, fertilisers and iron and steel plants.
According to the BICP, the country"s paper and pulp industry consumed 805 M Cu m of water in 1987-88 to produce 27 lakh tonne of paper. The specific water consumption by Indian paper mills is in some cases more than twice that of mills in USA. Some Canadian and Swedish mills are said to be practising zero discharge, meaning total recycling of water, thereby requiring minimum fresh intake.
Water conservation in the Indian paper industry will require maximum recycling of effluent discharge. The 2 reasons for high water use by the paper and pulp plants are -- use of hardwood and bamboo as input material (in other developed countries, paper is mainly produced from softwood) and employing outdated technology and machinery. If these hurdles can be overcome in a cost-effective manner, the consumption of water could be significantly reduced.
The effluents from the paper mills are dark brown to yellowish brown in colour due to the presence of non- biodegradable lignin and have a high Biological Oxygen Demand (BOD). The BOD value is the amount of oxygen that the microorganisms require to break down organic matter in water. The more the BOD, less is the water-dissolved oxygen available for higher animals such as fishes. BOD, therefore, is a reliable gauge of the organic pollution of a water body. One of the main reasons for treating sewage or wastewater prior to its return to a water resource is to lower its BOD and COD (Chemical Oxygen Demand) values. COD is the amount of dissolved oxygen that chemicals (that perform the same function as microorganisms) used to treat polluted water require.
The effluent characteristics differ from mill to mill. On an average, about 275 Cu m of effluent is generated per tonne of paper. All large mills have set up effluent treatment facilities and also practise chemical recovery and most of them follow the conventional method of treatment, namely, anaerobic (in the absence of free oxygen) or aerobic (in the presence of free oxygen) treatment or both depending on the nature of effluent. A BICP study conducted in September, 1989, shows that 12-20 per cent of the water in the effluent generated can be recycled, resulting in substantial reduction in fresh water consumption.
The study suggests that in the case of small paper mills, which are unable to individually afford effluent treatment plants, a centralised chemical recovery/effluent treatment plant could be set up on a cooperative basis for a group of mills situated close together.
Indian industrial plants consume far more water than their foreign counterparts
|Paper & Pulp
|Cu m/tonne of paper||230 to 450*||142|
|Fertiliser (9 plants)||Cu m/tonne of urea||9 to 40 **||NA|
|Iron & Steel Plants
|Cu m/tonne of cude steel||12 to 25 ***||1.2 to 8|
|Note: Position as at 1987-88 (*), 1988-89(**), 1993-94(***)|
Water savings achievable in fertiliser units
|Types of plant||No of plants studied||Water savings possible(%)|
|Gas based||3||3.6 to 18.5|
|Naphtha based||3||7 to 29|
|Fuel oil based||3||20 to 48|
Water is an important auxiliary input in fertiliser production. For a fertiliser production 6.5 million tonne in 1987-88, the industry consumed 124 M Cu m of water.
Depending on the feedstock (coal, fuel oil, naphtha and natural gas) and the process technology, the consumption of water for a tonne of urea varied from nearly 9 to 40 Cu m with the plants operating at rated capacity of 90 per cent and above (1988-89 base).
It was observed that the new generation Gas-based plants -- those constructed after 1985 and incorporating design features to conserve water -- had achieved a low of 6 Cu m of water per tonne of urea as compared to the corresponding figure of 14 Cu m in older plants. There is further scope in conserving water through reducing evaporation loss, which can be accomplished using evaporation-retarding chemicals.
Most of the pollutants from a fertiliser plant emerge in the form of the liquid effluent. The information obtained from various plants shows that the concentration of pollutants is reduced by appropriate treatment at different stages as well as mixing the streams of effluents of higher and lower concentrations of pollutants. Such measures are observed to have been adopted at a few fertiliser plants, where there is scarcity of water.
The BICP has estimated the possible water savings in consumption of raw water through water conservation measures in the different types of fertiliser units. The figures show that in fuel oil-based plants, the water consumption could be reduced almost by half (see Table 2).
If all the fertiliser plants in the country were to implement water conservation schemes, annual savings of 34 M Cu m of water, equivalent to Rs 239.15 Lakh (based on 88 - 89 water rates in different plants) could be effected. The corresponding capital investment for all conservation schemes taken together is Rs 510 Lakh and the pay back period ranges from about 6 months to 16 years. This brings out the fact that in most cases, it is possible to achieve reduction in water consumption without large capital investment.
IRON AND STEEL INDUSTRY
Steel plants consume substantial amounts of water because most of the unit processes, such as coke-making, are carried out at temperatures exceeding 1000 0 C and water is required for cooling purposes. The total water consumption by the Indian steel plants is estimated at 550 M Cu m per annum at the production level of 13.7 million tonne (as in 1993-94).
Of the total water consumption in steel making, nearly two-third is used up in (indirect) cooling in the Blast furnace and Steel melting shops. The water used for this purpose is segregated, cooled and recirculated. The remaining water required in the plant finds usage as carrying medium for solids and for direct cooling and washing. This is treated in a settling pond and either recycled, or alternatively discharged as wastewater (effluent) after conforming to statutory pollution regulations.
The factors specific to steel plants that contribute to the wide variation in the specific water consumption in this industry are: the type of coke-quenching (wet/dry), type and size of iron and steel furnaces, type of furnace cooling (cold water/hot water), iron and steel product mix, unit size and capacity of captive power generation.
The water pollutants arising in iron and steel plants are: suspended solids (such as scale, fly ash, bottom ash, coke), chemicals (pickle liquor, acid sludge, phenol), and oils. The very existence of these pollutants in water poses problems in optimum utilisation of water within the steel plant.
Benefits in terms of water savings in 2 steel units
|Plant||Scheme implemented||Scheme planned|
|No and description of measures taken||Investment (Rs annum)||Benefit
|No and description of measures||Investment (Rs annum)||Benefit
|Bhilai||6 (such as recycling of water locally & through cooling pond)||351||263||6(such as recycling of treated township sewage)||1,300||209|
|Bokaro||3(such as reclamation of water, bed drainage)||135||12||7(such as reclamation of filter backwash water, recirculation and reuse of water)||1,060||44|
In one of the plants studied, it was observed that the continuous recycling of wastewater to units through a cooling pond resulted in deterioration in water quality, and caused scaling in the cooling water circuits and an increase in algae in the cooling pond. This has affected the performance of water quality sensitive units such as the chemical water treatment plant.
Pollution control in the iron and steel plants, apart from improving the effectiveness of water usage, facilitates recovery of valuable by-products like oils, solids and chemicals, and also reduces pressure on fresh water demand.
The Bhilai steel plant was able to reduce its water consumption by 83 per cent during the 87/88 to 93/94 period by implementing water conservation schemes. Benefits in terms of savings in water quantity (reduction in the specific water consumption along with the investments involved on the various schemes are summarised in Table 3.
There are many factors beyond the control of the industry/plant management that influence the effectiveness of water management in industry. These include, inadequate availability of water in the region/location, level of water tariffs, government regulations pertaining to statutory limits on quantity and quality of effluent discharges, lack of integrated approach in the overall water management (storage and supply) among the government departments/agencies concerned towards optimisation of water usage. The 2 major exogenous factors are the supply of water from source to plant and the cost of water.
Industries that consume a large quantity of water such as paper and pulp units and fertiliser plants, obtain their supplies of fresh water from a variety of sources. The way in which water is conveyed to an industrial unit might become important in the context of water conservation. For instance, when water is conveyed through long open canals, a substantial loss of water occurs due to evaporation, seepage and other losses in transit. It would be useful to examine the mode of water supply to the 3 types of water-intensive industries listed earlier.
In the case of the paper industry, most of the paper mills get the water supply from rivers. Some also use groundwater.
A BICP study of 9 fertiliser plants (comprising a mix of plants based on different feedstock) found that water is taken from distances varying from 500 metres to 86 Km through pipeline or open canal. The sources also include ponds, stop dams on rivers, lakes, canals and bore wells. The quantity drawn yearly (1988-89) by these plants varied from 8 M Cu m to 27 M Cu m.
In the case of the steel plants studied by the BICP, the fresh water is obtained from river/reservoirs at distances varying from 30 km to 152 km through open canals. The canal losses for 2 of the steel plants are reported to be as high as 30-60 per cent of the total intake, especially where the canals are unlined.
Proper lining of the canals, therefore, needs due consideration to curtail avoidable canal losses which will in turn reduce the water intake rates substantially. The initiative for reducing such water losses needs to come mostly from the supply agency/authority concerned in the State/Central government.
Water being a natural resource, the cost of water is the cost of making it available for use. This involves storage, transportation and purification. In India, irrigation accounts for almost 84 per cent of the country"s total fresh water consumption. Water tariffs for irrigation are not based on volumetric measurement, but these may be flat rates or determined on the basis of area, type of crop and the income from the yield. In the same area, tariff charged for industrial users would be higher than that for the domestic users.
The share of water charges per unit cost of production in the case of the 3 industries discussed previously is shown in Table 4.
The wide variation in water tariff among the plants in the same industry can be attributed to local factors in the particular region such as water availability, scarcity/drought condition, demand from other users and the water pricing system followed.
The water charges as such do not constitute a significant component of the total cost of production in the industry. But the total water cost in the industry which includes handling (pumping), treatment and recycling, may be noteworthy. For example, in the case of 2 steel plants that the BICP studied, the water cost was 4.22 per cent and 2.66 per cent of the total cost of production.
Of the total water cost, a significant component is electricity (about 55 per cent), whereas water charges accounted for 15 per cent and 10 per cent for the 2 plants. The total expenditure on water supply and handling (pumping to various units once water reaches an industrial units reservoir), including pumping and chemical additives, is significant. This was Rs 43 crore and Rs 36 crore in the 2 steel plants for the year 92-93.
A trend towards more stringent environmental stipulation on the quality and quantum of industrial effluents and water scarcity in certain regions, are putting increasing pressure on industries for adopting measures for reducing water intake.
Also, the water tariffs for industrial supply have been increasing, rather sharply in certain regions. For instance, in the 2 steel plants that the BICP studied, the water tariff has increased from in Rs 0.28 per Cu m and Rs 0.23 per Cu m to Rs 0.63 per Cu m and Rs 0.70 Cu m respectively. But even the present water tariffs are not high enough to induce industry to take up water conservation.
This takes us to the important issue of rationalisation in the pricing of water. The water rate/tariff should reflect the true value of the resource. In a nutshell, determine the cost of water first, then link it with price incorporating penalties/incentives for inefficient/efficient use of water.
Apart from this, there is a need to explore the possibility of establishing integrated water linkages between the water intensive industrial plants and other prospective users. Presently, water linkages are between source and users. This could be further extended to have user to user linkage based on quality and quantity of water.
Effective water management should, therefore, include precise assessment of water demand and review mechanism (including monitoring and control), training and development of humanpower, water conservation including efficient transmission, prevention of losses in usage, recycling, effluent treatment. Also, a rational price structure that would reflect the true value of water should be introduced lest we run out of fresh water.
K B Thakur is deputy director (technical), Bureau of Industrial Costs & Prices, Department of I.D., Union ministry of industry, Delhi