The management of desalinated water

DESALINATION

'N" ';J tI ELSEVIER

Desalination 135 (2001) 7-23 www.elsevier.com/locate/desal

The management of desalinated water Taysir Ali Dabbagh Associated Water Management Consultants Ltd., I 0 Friars Gardens, Hughenden Valley, High Wycombe, Buckinghamshire, HP I 4 4LT, UK Tel. +44 (I) 494-563298; Fax +44 (1) 494-565816; e-mail: [email protected]

Received 10 October 2000; accepted 24 October 2000

Abstract

Desalinated water is expensive to produce so its efficient management from the inception of the water cycle at the desalination plant to the reuse of the sewage effluent from the treatment plant is of paramount importance. The water crisis in the Arab World is discussed and compared with the oil crisis when industrial counlries adopted policies and carried out extensive programmes for research and development in order to reduce dependence on oil and reduce its cost. This experience provides lessons for the better utilisation of desalinated water. The objectives for efficient management and proposed means of achieving them are presented. Three main lines of approach to improving the utilisation of desalinated water are discussed: reducing unaccounted-for water, re-using sewage effluent, and adopting new technologies. Potentially rewarding fields of research into advancing desalination are given, with an estimation of the cost and management suggestions. The potential for increasing storage capacity with natural underground reservoirs by adopting the technique of aquifer storage recovery is described. The importance of demand-orientated policies is emphasised, along with the need for restructuring and, most importantly, the establishment of a regulatory office to monitor the proper use of desalinated water. Keywords: Desalination; Water management

1. Introduction Desalinated water is still the most expensive source of water when compared with other sources, but if natural water has to be pumped over long distances it can become just as expensive as desalinated water, depending on the distances involved and the amount of pumping

required. The efficient management of desalinated water supply and sanitation systems is thus becoming increasingly important. Reductions in the cost of desalinated water have invariably been regarded as related to improvements in technology. While further improvements in desalination processes are certainly desirable and need to be sought for, it is becoming

Presented at the International Conference on Seawater Desalination Technologies on the Threshold of the New Millennium, Kuwait, 4-7 November 2000.

0011-9164/01/$- See front matter © 2001 Elsevier Science B.V. All rights reserved PII: SOOl 1-9164(01)00135_7

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T.A. Dabbagh ~Desalination 135 (2001) 7-23

ever more important that desalinated water should be managed efficiently as there are already a very large number of desalination plants in existence in the Arab World. These are being operated under a variety of management systems in both the public and private sector. Water shortages in the Arab World are increasingly focussing attention on the use of desalinated water since most of the population resides along the shores of the major seas and oceans of the area and the region contains a considerable number of aquifers bearing brackish water. Desalination is thus increasingly being favoured as an option for supplying water in the Arab world. Already the region is moving ahead of the rest of the world with regard to the volume of water desalinated, not only in the oil-producing countries but also in other Arab countries. The management of desalinated water must consider the full cycle from the inception of the water at the desalination plant to the reuse of sewage effluent at the treatment plant.

causing drought over several agricultural seasons. Half this critical level, 500m3/head/y, is considered the scarcity level at which a country is obliged to limit its agricultural development, otherwise it will face substantial problems in providing water for domestic and industrial use. Fig. 1 shows that up until the year 2025 Iraq, Mauritania and Lebanon will still have water available from renewable water resources above the critical level. However, by then the water available per capita in Syria, Somalia, Morocco and Sudan will have fallen below the critical level. In the rest of the countries of the Middle East, including Israel, the water available is already below the critical level and by the year 2025 it will be below the scarcity level, except in Egypt, Syria and Morocco where it will be marginally above this level. These projections assume that water management in these countries will stay virtually the same and traditional methods of irrigation will continue to be used. They also assume that the rate of population increase in these countries will continue to be virtually the same.

2. Water crisis

The accuracy of assessments of renewable water resources in the Middle East varies from one country to the other, depending on the time span over which data has been collected and the amount of exploratory and investigative work which has been carried out on renewable water resources in the Arab World and Israel. Most of the estimates shown in Fig. 1 are the average of several different sources of information. In some countries, however, the amount of renewable water resources is considered to be confidential information and can be disputed. The critical level for renewable water resources is estimated to be 1,000m3/head/y. At this level a country has sufficient renewable water resources to maintain its agricultural development, but could be exposed to a critical situation if adverse weather conditions occur

3. Oil crisis

The projections for reliance on oil, made by leading experts in oil production in the seventies caused considerable concern in the industrial countries following the increase in oil prices. Fig. 2 shows the expected increases and the real production of oil. It is evident that the projected estimates were far too pessimistic and that real oil production did not prove any of these predictions correct. It is worth asking why these predictions were so wrong when they were done by top industry experts. In fact, they were not wrong! Research has found that most of these predictions were qualified with the proviso that they would be reached if no changes in policy or management were undertaken by the industrial countries regarding oil use.

T.A. Dabbagh / Desalination 135 (2001) 7-23

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countries with particular supply difficulties, suddenly increased Every major consuming country introduced a set of mandatory conservation measures accompanied by an information campaign aimed at encouraging voluntary reductions in consumption. The policies of OECD countries for conserving energy and utilising it more efficiently had the following objectives [1] • Achieving security of supply • Maintaining a reasonable cost of imported energy • Maintaining reasonably stable price levels • Attaining equilibrium in international payments • Maximising economic efficiency

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• Protecting the environment • Controlling business activities • Controlling access to the industrial countries own resources Energy conservation possibilities were considered in the various sectors of the economy - electricity conversion, industry and transport, as well as the residential and commercial sector q in order to show the potential savings to be made in sectoral consumption, the cost benefits, and the type of policy actions available. It was concluded that, by better energy management and the reduction of waste, an increase could be brought about in the proportion of the total primary energy input that was actually used. In fact, the adoption by the OECD countries of the policies outlined above, commencing from 1974/5, led to results that surpassed expectations and brought about a reduction in energy consump-

tion within a shorter period than was anticipated. In the late seventies almost all leading specialists and oil experts, including the OECD, expected that OPEC oil exports would continue to rise, but they underestimated the effect of the OECD measure and from 1979 the export of OPEC oil dropped sharply. The predicted oil production for the eighties and nineties, as estimated in 1981 by adopting different scenarios, are shown in Fig. 2, together with spotted predictions made in earlier years [2]. As a result of actions taken, the price of oil settled near to its price prior to the oil crisis [3], as seen in Fig. 3. It is evident that the predicted and actual productions were very different: oil production was expected to be much higher than turned out to be the case. In 1985, the industrialised countries used 30% less energy and 40% less oil to produce a unit of GNP than they did two decades previously [4].

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4. Management of desalinated water

As potable water has become everywhere more precious and increasingly stringent rules and regulations have been introduced relating to its acceptable quality, the management of water supply schemes has had to make much more effort to conserve and utilise every drop of water from inception to reuse. When there was a cheap source of cheaply treated water, such as readily available surface water requiring only minimal treatment, unaccounted for water was not seriously tackled,since the cost of renovating distribution networks in old cities would not be recovered by its reduction. Since the seventies, however, much more activity has been concentrated on this aspect of management. Efficient management, however, requires more than this. It has to be in control of the desalinated water cycle from its inception with the production of the potable water at the desalination plant to the reuse of sewage effluent leaving the sewage treatment plants. At present, the responsibility for producing desalinated water and the treatment of sewage is fragmented among a number of ministries and departments in the Arab World, but the wider the spread of the authorities dealing with the cycle of desalinated water use, the less efficient is the management of the water sector and the greater the misuse of water resources.

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The management of desalinated water should aim to achieve the following objectives: • Water security. This requires water resources to be available and sustainable within the boundaries of the country concerned. If the desalination option is viable, it can have a major advantage over conveying water long distances across the borders of countries. • Cost reduction of desalinated water. This can be achieved by better management as well as research and development. • Sustainable economic growth. This cannot be achieved without reliable and reasonably priced sources of water. Desalination may be the only viable option within the borders of the country concerned for sustainable economic development. • Affordable water for lower income groups. This must be maintained when considering tariff structures. • Protection of the environment. This can be achieved if the sewage effluent resulting from the treatment of used desalinated water is better utilised. The policy and procedure for the efficient management of desalinated water has to rely on an integrated programme that places emphasis on the following major activities as shown in Fig. 4: • Operations Unaccounted for water Reuse of sewage effluent Performance of desalination plants Advancing the relevant technologies Research and development Aquifer storage recovery Management Demand management Restructuring Regulatory office

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T.A. Dabbagh / Desalination 135 (2001) 7-23 Management of Water from Inception to Reuse

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Fig. 4. Elements of water managementfrom inceptionto reuse. 4.1. Operations To make better utilisation of desalinated water three major factors come to the fore. One is the reduction of unaccounted-for water (UFW), the second is the appropriate re-use of sewage effluent, and the third is improving the performance of desalination plants. 4.1.1. Unaccounted-for water A major factor in the management of desalinated water is to bring about a reduction in the volume of unaccounted-for water, that is the difference between the water produced and the water sold or recorded. Unaccounted-for water includes water used but not paid for, as well as water wasted through leakage. However, it is of paramount importance to obtain true figures for unaccounted-for water, since they are required in order to proceed with sound approaches to reducing it. If UFW is not measured the effect of repairing leakage may not be realised. It is usual

to reduce losses and then to determine their impact by measuring unaccounted-for water. Repairing one pipe, for instance, may lead to the bursting of another if the hydraulics of the system is not properly designed. Thus, leakage reduction can lead to a design review in order to sustain reasonable hydraulic pressure. A number of factors affect the accuracy of figures for unaccounted-for water which may be under-estimated or over-estimated, though the latter is less likely. Reliable measurements of the water produced depend on the accuracy of the meters used. Sometimes measurements of water production are given in terms of hours of pumping rather than flows or volumes. Water can be lost not only for technical reasons, but may be unrecorded because it is used but not paid for. Such water includes that used for firefighting, illegal connections, operation losses, or water used by consumers whose meters are under-registering. Water sold by tankers, for instance, may not be recorded and invariably the

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T.A. Dabbagh / Desalination 135 (2001) 7-23

overflow of water from distributing water tankers is not considered. It is easiest to determine UFW if all consumers have meters. Usually minimum night flow is measured in a particular zone. This is only possible if there is a 24-hour supply, all customers have meters, and the points at which water enters and leaves the zone are clearly identified. The accuracy is reduced if consumers have storage systems that fill at night. The recording of UFW has developed dramatically in the last two decades, particularly in industrial countries where water is plentiful. It used to be difficult as water was produced on a flat-rate basis. Fig. 5 shows diagrammatically the relationship between the level of leakage, the cost of leakage, and the cost of leakage reduction. The cost of leakage rises as the level of leakage rises in a linear relationship, providing the source of water does not change and the unit cost of producing water at that source is constant. The cost incurred when reducing the leakage is not quite so simple. As the level of leakage is reduced, the effort required to reduce it further becomes higher and the location of small leakages becomes more difficult. The assumption is made that the cost of reducing leakage to zero is infinite and therefore the cost of leakage detection has an inverse relationship to the level of observed leakage. Thus the total cost of the leakage detection programmes for a particular zone is the sum of these two costs. The optimum level of leakage is that where the overall minimum cost is observed. The levels of UFW in major industrial cities were shown in some places to amount to nearly 50% in the late seventies. Figures of 20% to 30% used to be regarded as moderate and efforts to reduce them an unnecessary cost. Today attitudes have fundamentally changed and the level of losses has had to be reduced because of increasing production costs and the trend for privatisation which introduces profit incentives to increase efficiency and conserve resources. Some water

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Fig. 5. Fixingoptimalpolicyfor leak detection. authorities have reduced the level of UFW to less than 10%. The announced figures in the Gulf region for unaccounted-for water vary from 20% to 25%. However these figures are not always well justified. Because of the high cost of producing and distributing desalinated water in the Gulf, the optimal level of leakage should be less than 10%. The prevailing procedure in most Arab countries of reducing UFW without quantifying the increase in available water minimises the impact of any reductions in water losses. It is essential to publish both the amount of water produced and the amount billed. Although there is considerable controversy about levels of UFW, the need to record the amount of UFW is undisputed. Improved data acquisition and analyses will help to reduce the level of uncertainty that remains and allow the authorities concerned to promote better solutions. 4.1.2. Reuse o f sewage effluent

Total wastewater flows are rising rapidly worldwide and have been widely exploited in quite a few places including India, Mexico City and Johannesburg. The effluent is used after

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T.A. Dabbagh / Desalination 135 (2001) 7-23

appropriate treatment, usually in stabilisation ponds, and no major disease outbreaks have been reported. In Arab countries, the present ways in which sewage effluent is used varies between widely differing extremes. Some countries, especially the oil producing countries, have adopted a zero risk policy whereas others are using raw sewage effluent for irrigation purposes. A well-balanced and sustainable approach is badly needed. Whereas in most countries the wastewater volumes are small relative to the total renewable resources available, in the Gulf wastewater flows may represent the predominant long-term water supply for intensive, irrigated agriculture. Since they are both perennial and reliable, there are sound economic and technical reasons for using them extensively and appropriately. Factors affecting the extent o f reuse. These were the subject of a survey, carried out by the author in 1995, in which international consultants were asked about treatment plants they had worked on. Few of the consultants had reuse experience, and less than a fifth of the treatment plants constructed produced effluent for reuse purposes. Among the constraints listed as acting against reuse, the main ones were cost and disease transmission. However, in the Gulf, both these factors have already been dealt with. The cost of treatment has been met and the risk of disease transmission has been eliminated by adopting a high standard of treatment that produces effluent with a quality exceeding WHO guidelines. Nevertheless, vast amounts of effluent are disposed of because they do not meet these high standards. It is difficult to justify the low utilisation on a sound economic basis. It seems that in the Gulf the main constraints are, perhaps, psychological objections, and misunderstanding of treatment required. In general reuse is perceived, in most parts of the world, as lacking public support and involvement. Among other conslraints mentioned were

the ready availability of raw or potable water, inadequate control of operation and maintenance leading to poor quality effluent and consequent health hazards, technological problems such as irrigation systems not adapted to effluent reuse, the level of crop restrictions imposed, and the possibility of effluent being accidentally used as potable water. The most important steps to be taken to promote reuse were regarded as the adoption of disease control precautions, followed by social awareness campaigns, and setting realistic treatment standards. Determining areas for cost reduction was not considered of major importance, indicating that sufficient technologies already exist for treating sewage appropriately at reasonable cost for irrigation purposes. Other measures suggested for promoting reuse included increasing public awareness by educating children, changing the attitude to water so that it was regarded as a limited resource, demonstrating that the benefits of reuse outweigh cost, and identifying the need for reuse and marketing it. Also cited was the need to update, upgrade and perfect irrigation techniques, use the appropriate technology, introduce dual water reticulation schemes or water blending, and permit the irrigation of a larger range of crops. Reuse could also be made more acceptable by improving the control of operation and maintenance to ensure adequate treatment standards are attained. Reuse research. Various areas were suggested which might help make reuse more acceptable and bring down costs. These topics were mainly in the areas of disease transmission, social awareness and attitudes, scientific bases for effluent standards, risk assessment, pollutants, process technology, irrigation and crop studies. Management and public administration were regarded as very important for reuse being adopted successfully, as reorganisation in these fields could help to improve the co-ordination of water supply, water treatment and reuse

T.A. Dabbagh/ Desalination 135 (2001) 7-23 authorities. Improving the institutional set up and training of personnel would result in a higher quality effluent. The setting of appropriate effluent standards is crucial. Sewage effluent from tertiary treatment, as produced in the Gulf, can be of better quality than some river water that is used for irrigation. Gulf countries have refrained from using effluent unless it is treated to a very high standard as effluent use is regarded as unnatural. The availability of f'mance has made it possible to polish sewage effluent to a standard approaching that of drinking water. It is then used to produce animal fodder or carry out other uneconomic agriculture, while effluent that fails to reach this high standard is discarded as substandard. A universally high treatment standard is applied in the Gulf for the full protection of public. This is similar to the situation in the USA where 'zero risk' is required, although in fact there is always some risk. In many other warm climate locations, instead of the complicated and expensive tertiary treatments adopted in the Gulf, the preferred method of treatment prior to reuse when land is available at reasonable cost - - is the use of stabilisation ponds that can also be designed to meet WHO guidelines. Pin-pointing objectives when trying to maximise the reuse of sewage effluent is just as important as it is when trying to lower levels of unaccounted for water. The purpose for which effluent is to be reused needs to be identified. The standard of treatment adopted must suit this purpose and be justified economically and environmentally.

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4.1.3. Performance of desalination plants The performance of desalination plants depends on the efficiency of the operation and maintenance teams. There seems to be a great deal that needs to be done in this respect. As will be seen later in this paper, improvements in the operation and maintenance of existing plants is

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regarded as having the greatest potential for reducing the cost of desalinated water. There is a need for 'case studies' of desalination plants that have been in existence for a long time since consultants and manufacturers complain about the dearth of records and data regarding the difficulties encountered in the operation of desalination units in the GCC countries.

4.2. Advancing appropriate technology Two aspects of technology are of particular interest for improving the management of desalinated water. One is supporting research and development by the Gulf countries, and the second is embarking on the use of new technologies that increase storage facilities by using natural underground reservoirs.

4.2.1. Research and development The approach to research in desalination has passed through various phases. The earliest research, which resulted in the development of the multistage flash (MSF) system, was instigated in the Gulf region in the fifties [5]. Major contributions to the development of reverse osmosis, as well as the refinement of other processes, were made by the Office of Saline Water (OSW) in the United States prior to its closure in 1972 [6]. Research centres in the Gulf have contributed to refining the design, operation, and maintenance of desalination plants. Being supported by the public sector, they have made the results of their research public and have sometimes managed to intensify competition between manufacturers and therefore reduce costs, especially in the case of scaling prevention chemicals, the prices of which have been drastically reduced. They have also contributed to an improvement in various aspects of plant operation, thereby increasing plant life spans [7]. Elsewhere, public sector research in desalination is limited [8] and with the prevailing trend

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T.A. Dabbagh / Desalination 135 (2001) 7-23

towards privatisation, research institutions arc far more inclined towards those projects which are most certain to be fmancially rewarding. Much of the developments in desalination have been made by the desalination industry as it has gained practical experience. This has had several consequences: competing manufacturers have duplicated research; they have kept results to themselves; and they own the patents [9]. They maintain, quite rightly, that the results of research cannot be made public free of charge, being the result of hard work and major expenditure on the development of processes and components [10]. In view of the current water situation in the Arab World and other arid and semi-arid regions, there is an outstanding need for fimding public research into desalination processes, and also for the compilation and dissemination of the extensive data which has already been expensively earned through the design, operation, and maintenance of desalination plants. Investing money in public desalination research will have the advantage over investing in the long distance conveyance of water in that the latter is an old technology with limited scope for improvement, and commits vast amount of capital for a long time horizon, while desalination can benefit substantially from further research. Indeed, for the Gulf region, investment in public research can be regarded as an investment in the future of the region. Since it already has a policy of investing abroad to ensure future post-oil income, investment in the development of desalination could be doubly beneficial: not only would there be a financial return in the form of profit and investment, but also - - since the Gulf is the main market for desalination technology - - a benefit from gains in technological efficiency brought about by the public research. Thus the major beneficiary from advances in desalination technology would be the Gulf region. To a lesser extent, other parts of the Arab world and some developing countries facing major shortages of sources of potable water would also

benefit, should desalination become a cheaper and therefore more attractive option. Industrial countries would also gain, but mainly from improvements in some of the processes involved in refining the quality of potable water - - for which standards are now becoming very slringent and the commercial rewards that come from having the major manufacturers based there. Apart from cost reductions brought about by technological improvements, investment in public research in desalination, where the results arc not patented, could bring about reductions in the cost of desalination through the following effects: • A reduction in the capital cost of desalination plants and their components. This would occur if manufacturers reduced their research budgets when publicly financed research is undertaken. • An intensification in competition between manufacturers. The results of public research might encourage manufacturers, such as ship builders, to produce similar desalination plants and components. • Elimination of the duplication of research. Public research would help reduce the duplication which often results from the confidentiality sustained by the manufacturers who wish to be the major beneficiaries of research financed from their own private resources.

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Identifying research requirements. To promote public research in desalination technology it is necessary to identify fields of research that are expected to substantially reduce the cost of producing desalinated water. Major possible research fields were selected from publications on the subject by specialists in desalination mainly from Saudi Arabia [7], the USA [9], and the UK [ 11]. It is also important to estimate the cost of carrying out the necessary research, so recommendations can be formulated, budgets can be estimated on a sound basis, and decision makers assisted to take a stand on the issues involved and perhaps to promote them.

T.A. Dabbagh / Desalination 135 (2001) 7-23

To try to identify major research requirements a survey was conducted among organisations and individuals involved in desalination, either as consultants, manufacturers, managers researchers or academics. Over one hundred questionnaires were sent out inviting the recipients to indicate in the form of percentages, their views on possible major research fields, with regard to their priority for bringing about a possible cost reduction in desalination and suggestions for the time and man/months that might be required to achieve it. They were also asked to add further research fields if they were not included in the questionnaire's list. Some of the aspects of the fields that seemed to need investigation are outlined below. Fields o f research into distillation processes

1. Scaling prevention techniques for film evaporation. Considerable progress has been made in reducing scaling on the MSF tube surfaces, but this seems to have led to scale deposition being transferred into the flash chambers and causing blockage of the demisters. 2. Corrosion reduction. There is a need to develop alloys and other materials for moving and non-moving parts with corrosion resistance similar to those that have been recently developed but at more economicalprices. 3. Large-scale capacity increase. Increases in the capacity of distillation plants, in pursuit of economies of scale, require the development of the bases of design using mathematical and modelling techniques to establish the optimum plant size - - that which can provide desalinated water at the lowest cost. 4. Heat transfer improvement. New alloys with higher heat transferability than those presently available could improve the efficiency of MSF drastically. 5. Computer control of processes. The appropriate and reliable control of a desalination plant is a major element in reducing the cost of

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operation and maintenance as well as contributing to lengtheningthe life span of the plant. 6. Flexibility of water/electricity production. The fluctuation in demand for water and electricity requires higher efficiency in operating the turbines linked to desalination plants so that the production of either electricity or water can be varied without having to waste energy or shorten maintenance periods. 7. Computer modelling. Advances in this field might reduce costs if computer modelling could be effectively utilised to simulate desalination plants under adverse operating conditions. Fields o f research into membrane processes

1. Chlorine-resistant seawater membrane. Disinfection of the feed water supplied to the membrane systems of reverse osmosis plants is essential to prevent biofouling of the membrane surfaces which inevitably leads to a loss of performance. Chlorine is by far the most costeffective water sterilant for potable water, but unfortunately modem RO membranes are generally susceptible to chlorine damage. There is a demand therefore for membranes that are able to tolerate biocidal concentrations of chlorine in continuous operation over several years. 2. Fouling and scaling mechanisms. Fouling of RO membranes is probably the most important factor contributing to the overall cost of operation of RO desalination facilities. The adverse economic impact results from the need for sophisticated systems and/or more frequent membrane replacement. A more fundamental understanding of fouling and scaling mechanisms may ultimately provide information that leads to lower operational costs. 3. Seawater coagulation and filtration techniques; Silt density index (SDI) reduction. The need to pretreat seawater to reduce SDI can sometimes be eliminated by taking seawater from boreholes, but in the running of large seawater RO plants with open seawater intakes, the

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T.A. Dabbagh / Desalination 135 (2001) 7-23

removal of all organic suspended and colloidal matter is a major problem. It is normally carded out using classical water treatment coagulation and filtration techniques. Although these are well advanced for use in the water supply industry, research into broader spectrum coagulants might be of benefit and the new technology of microfiltration should be given more consideration and developed further. 4. Membrane performance in a typically variable chemical environment. RO membrane efficiency increased with the reduction of the salinity of the inflow. Mixing sewage effluent with seawater would reduce the salinity, but make the composition more variable. This is the situation when wastewaters are reclaimed using RO since most of them contain dissolved organic compounds varying in chemical properties and molecular weight. The problem is further complicated if the water is chlorinated. It is important to determine to what extent the molecules of undesirable chlorination by-products are rejected by RO membranes. In addition, certain organic compounds are known to interact with membranes causing adverse changes in performance. 5. Feed water disinfection, alternative strategies. Drawbacks to chlorine treatment for disinfection of feed water to prevent biological growth on active membrane surfaces involve potential membrane degradation and the formation of undesirable chlorinated compounds, such as trihalomethane (THM) which may be carcinogenic [9]. A variety of other biocides such as ozone may prove to be advantageous in RO systems but have not been adequately studied. 6. Energy recovery devices. The cost of energy is the main factor leading to increases in the cost of desalination, so research is required to improve the efficiency of energy utilisation. Promising fields o f research. Thirty-three respondents completed the questionnaires and a further 15 provided information on desalination research. Respondents had been asked to rate, as

a percentage, the relative importance of the above fields of research, operation and maintenance, and hybrid plants. Overall, the most important field for future development was regarded as operation and maintenance strategies. With regard to the specific technical fields, considerably more responses related to membrane processes than distillation processes indicating greater interest in the later. For membrane processes, top priority for research was given to chlorine-resistant seawater membranes and fouling and scaling mechanisms. For distillation processes top priority was given to scaling prevention and corrosion reduction. Hybrid plants were given relatively low priority. Cost reduction. The survey invited suggestions as to the possible cost reductions to result from major research efforts in the various fields. The largest potential cost reductions were suggested for distillation processes, suggesting that a clearer vision exists regarding the requirements for further research into the oldest desalination technology. A relative lack of confidence in the outcome of membrane research may have also been due to the relatively large number of manmonths proposed. Funding sources. The funding available for public research on major industries is limited and normally comes from the industrial governments concerned. Much greater funding than the amount normally allocated is required to make a major impact on the desalination process. However, such allocations have been reduced in recent years along with allocations for public research in desalination, for which industrial countries do not seem to consider that there is a particular need, and are apparently satisfied with the progress made by the private sector. Because of the increasing demand for desalination and the apparent monopoly in certain areas of the desalination industry, the private sector appears to be able to recover its research expenses with a margin of profit from the users of desalination, who are mainly in the GCC countries.

T.A. Dabbagh/ Desalination 135 (2001) 7-23 While in-house research improves the quality of manufactured desalination products, it also increases costs and strengthens monopolies. Moreover, manufacturers normally concentrate on the least risky research work so as to ensure both cost recovery and profit. Main manufacturers cannot afford the high risk, long-term research programmes needed to produce significant reductions in desalination cost. Also, the strongly conservative nature of the market discourages innovation, since pioneering technology involves more risks of operating problems - - low capacity, poor availability, lower water quality, and higher maintenance - - than proven technology; no customer wants the first unit of a new design. It is difficult to get manufacturers to sponsor the development of laboratory scale systems owing to the huge size gap between them and the modules being sold. It is evident that the major beneficiaries of public research in desalination are the users, who are basically the GCC countries. It is therefore in their direct interest to invest in public research so as to intensify competition and reduce costs. The annual budget required for this purpose is estimated from the questionnaire to be about US $65 million, which represents Jess than 1% of the GCC countries' oil income. It is, therefore, a reasonable budget for the GCC countries. The need to increase the availability of water, not only to satisfy increasing water demand, but also to diversify income by encouraging their industrial sector in particular, cannot be achieved without establishing a reliable source of water which has to be desalination. Management of research. Management of research will most probably be more difficult than finding the funding required for carrying out the research needed. There is considerable evidence that unconstrained research becomes academic and does not lead to a commercial product. It is said that research and development is only viable if there is a commercially acceptable end product which will be accepted in the market place.

19

Selection of basic research projects must depend on the possible contribution that may be made to the understanding of a larger phenomenon, the track record of the principle investigator, and the originality of the proposed work. Deciding when to discontinue research may be more difficult than starting it. Reviews should consider whether results are just measurements or a discovery. In the case of applied research - which should be easier to judge on useful results - - many papers report the intense analysis of minutiae of little relevance to improving product or process, or go over old ground because researcher and funding agencies may not be up to date as to what are the real problems and the practical and economic limitations. The management of research therefore requires international specialists who are familiar with the development of the industry and have objective views on the selection of research fields which are under consideration for financing.

4.2.2. Aquifer storage recovery Definition. For fuller utilisation of desalinated water, and hence further cost reduction, greater water storage capacity is required. To this end, aquifer storage recovery (ASR) could be used. This is a system that has been in use in the USA since 1984. It has been developed to improve the use of water supply and water treatment facilities. The system involves the use of injection wells for the underground storage of treated drinking water in a suitable aquifer when the capacity of water supply facilities exceeds the demand, and its subsequent recovery from the same well to meet seasonal, peak, emergency or long-term demand as shown in Fig. 6. ASR may be used to store surplus water in this way. Also where electricity from a dual-purpose plant is in low demand ASR can be used to inject desalinated water into the aquifer. Such seasonal storage may amount to millions of cubic meters through a single well, compared to a few hundred stored in conventional

T.A. Dabbagh / Desalination 135 (2001) 7-23

20

wm

ammul

4. 3. Managerial changes

A~

A',~Ip

of the undesirable by-products of chlorination [13].

7/77 /7 //F/77,

A~

Fig. 6. Typicalaquiferstoragerecoveryoperatingschedule.

ground or elevated storage tanks to meet demand variation. Aquifer storage recover is low cost where a suitable aquifer is available, since land requirements are minimal. Practical experience. It has been shown that by making more efficient use of existing water supply systems, ASR can reduce capital costs by 50% to 90% [12]. However, this system has not as yet been used in conjunction with desalinated water, although it has been considered in Kuwait, Saudi Arabia and Oman. In each of these countries it has been planned in conjunction with desalination facilities to provide a strategic water reserve for emergency supplies while also meeting other secondary objectives such as seasonal peak demands, recharging brackish water reserves, and salinity intrusion control. In June 1993 there were approximately 60 ASR projects in operation or under development in the USA [13]. Experience in ASR pertinent to the Gulf region occurs in Florida where at least four sites are in operation that have brackish or seawater aquifers with similar characteristics to those found in the Gulf region [14]. Treatment of the recovered water is generally unnecessary apart from disinfection. There is some evidence that ASR results in the elimination

Management changes are perhaps the most difficult to implement and also the most time consuming. They involve carrying out social awareness campaigns, reshuffling the institutional set-up, and introducing monitoring systems for regulating the proper utilisation of desalinated water.

4. 3.1. Demand management Up till now, Gulf governments have always emphasised supply management, which covers the activities required to locate, develop and manage new resources. However, today they are finding it increasingly necessary to turn their attention to demand management as new water sources become more and more inaccessible and the cost of projects to augment supply escalate. Demand management includes the promotion of more desirable levels and patterns of water use. It covers both direct measures to control water use, such as regulations and technological means, and indirect methods that affect voluntary behaviour, such as market mechanisms, financial incentives and public education. The mix of demand management measures may vary, but in all cases it aims to conserve water by increasing the efficiency of its use. A key issue in the management of demand is to educate the public that water can no longer be taken for granted and used extravagantly. Its production and distribution is a major burden on the budgets of Gulf governments since consumers contribute only 5% to 10% of the cost. Some industrial countries have successfully reduced water consumption, in spite of industrial expansion, by taking administrative and technical measures. In the Gulf emphasis should be placed on improving the utilisation of existing

T.A. Dabbagh / Desalination 135 (2001) 7-23

facilities. When these countries, with abundant money and a shortage of qualified staff, were rushing to catch up with established modem states, management was more concerned with construction than with operation and maintenance and capacity building. Now that a high standard of infrastructure has been substantially achieved, it is prudent to plan for its optimum utilisation. The facilities for generating electricity and water could be adequate for some time into the future if their management could be directed towards their more efficient utilisation. In many eases they have been overdesigned, as ot~en occurs following a substantial increase in national income. It is said that London benefited from over-designing by the Victorians as they used the increased national income from he expansion of the British Empire. Like Britain, some other European countries also benefited from the expansion of their empires and the export of manufactured products produced following the industrial revolution in the eighteenth century. It is essential to make the water sector more competitive. Whereas in most countries in the world a water tariff system operates to cover at least the cost of operation and maintenance, in the Gulf the subsidies for the water, electricity and gas sectors are so high that these utilities are either free or supplied at a nominal charge. This situation needs to be readjusted so that irresponsible usage is avoided and the use of water is limited to satisfying the basic demand, while not forgetting that the availability of water is a prerequisite for a healthy society. The present incentives and subsidies for irrigation in the Gulf region will also have to be reconsidered, not only because of the increasing cost, but also because of the adverse effect on the environment of depleting non-renewable water resources. Whereas in industrial countries the establishment of a data bank and keeping audited records are considered essential, management practices in the Gulf have developed differently

21

and such practices seem to be rare. Financing agencies try to encourage them by demanding m before granting a loan - - financial analyses from water authorities, including audited figures for income and expenditure and the amount of unaccounted-for water. Establishing basic data is fundamental for locating the major drawbacks of water systems since they provide the incentives for taking measures to improve the system. However, data on water losses, reuse of sewage effluent, and the cost of producing and distributing water is much less accessible and verifiable in the Gulf than in industrialised countries. This is a major area for improvement. 4. 3.2. Restructuring

A high degree of coordination is more likely to be achieved by a single authority responsible for water production, distribution and reuse. An institutional set-up is needed that is in control of all stages of the water supply cycle, from its inception with the production of the potable water at the desalination plant to the reuse of the sewage effluent leaving the sewage treatment plant. This overall control is necessary because the cost of desalinated water is not linked solely to efficient plant operation, but also to several other factors such as the storage capacity available, the amount of unaccounted for water, and the extent of reuse of sewage effluent. Such a single unified authority can encourage privatisation on a sound basis, reduce unaccounted for water, make better use of sewage effluent, and use aquifer storage recovery whenever possible to utilise the large installed capacities of desalination plants more effectively. Strategic planning is carried out more effectively by a water authority which is in control of the collection and treatment of sewage as well as the production of water, since it is not only concerned with satisfying water demand, but also with making better use of the resulting sewage effluent.

22

T..4. Dabbagh / Desalination 135 (2001) 7-23

To make sound planning possible and to avoid the squandering of water resources a major movement of staff and strategists is required. Amalgamating the authorities could be achieved in stages. Many important activities should be decentralised to autonomous, local, private, or user entities, since stockholder participation in decision making promotes accountability and transparency, and also nearly always leads to solutions that are more efficient and resilient. The best staff could be integrated to form a core that would provide a dynamic approach within the authority concerned. Where duplication of work exists, staff could be offered early retirement or soft loans for setting up private enterprises which could participate in running the water and sanitation sector. 4. 3.3. Regulatory authority

It now appears that bringing about the rational use of desalinated water requires the establishment of an independent regulatory office that can ensure adherence to the rules and regulations that a Government has put in place to achieve its objectives. Such regulatory authorities are now quite common in industrial countries where they have been established to regulate the privatised water authorities. In the Arab World there are still only a limited number of privatised water authorities, and most water and sanitation authorities are in the public sector. These public authorities need to be assisted by ensuring that their operations and performance are progressing in the right direction towards ensuring an efficient system for managing desalinated water from inception to reuse. The private sector can assist the public authorities by monitoring its performance. A private monitoring office working directly for, say, the Ministry of Finance can take responsibility for ensuring the proper operation of the metering system, which is of paramount importance for working out the unaccounted-for water. It can assess whether sewage effluent is

being reused properly and on a viable economic basis, and provide assistance with improving its utilisation. The office can also suggest regulations and appropriate penalties for infringing them. When water and sanitation authorities have been monitored by a regulator before privatisation, better and more realistic transfers can be achieved. A private regulatory office can nominate public authorities for privatisation. When water and sanitation authorities are privatised, the private office can be converted into a public office. An example of a regulatory system is provided by that set up in England and Wales when the water supply and sewerage industry was privatised in 1989. The new private companies formed operate under licence subject to the control of three regulatory bodies: the Environment Agency, The Drinking Water Inspectorate and the Office of Water Services (Ofwat). A number of previous authorities and departments were gathered into one regulatory organisation, the Environment Agency, making possible a comprehensive approach to protecting and enhancing the environment. This Agency combines the regulation of land, air and water, and has a remit covering pollution control, the general management of water resources including resource planning, the licensing and regulation of abstractions from ground and surface water, fisheries regulation, flood defence, conservation and recreation. The Agency also takes action against unauthorised pollution discharges and constantly monitors water quality. Ensuring that legal standards of drinking water quality are met is the task of The Drinking Water Inspectorate. Water companies have a duty to supply wholesome water that conforms with standards laid down in water quality regulations. The Inspectorate checks the results of sampling and analysis carded out by the companies under the regulations. Where standards have not been met companies enter into legally binding undertakings to install additional treatment.

T.A. Dabbagh / Desalination 135 (2001) 7-23

Economic regulation is provided by the Office o f Water Services (Ofwat) a non-ministerial government department funded by a budget recovered from industry through the licence fee. The Office supports the Director General of Water Services. He has to balance the pressure o f ensuring, on the one hand, that water and sewerage companies can carry out and finance their specified functions and, on the other, that customers are not overcharged and the services they are provided with are safeguarded. He is responsible for promoting economy and efficiency, facilitating competition, setting prices, monitoring each company to ensure that it complies with the conditions of its licence and that investment programmes deliver the promised improvements, and also for comparing the performance o f different companies. Ten years on, the privatisation of the companies under the above system of incentive regulation has been regarded as a success, although it has been necessary to make some modifications along the way. Prices have fallen back to pre-privatisation level, after initial rises caused by the obligations to provide higher standards o f drinking water quality and better protection o f the environment. A countervailing effect on prices has come from the greatly increased efficiency o f the companies in terms of capital maintenance, quality enhancement and the raising o f finance. The shareholders have had a good return, the delivery of services to the customers has improved, and the environment has improved dramatically. It is claimed that in England and Wales "most of the environmental damage of past 200 years will have been repaired by 2005".

References

[1]

OECD, A Report by the Secretary General, Energy Prospects to 1985 - - An Assessmentof Long-Term Energy Development and Related Policies OECD, Pads, 1974.

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[2] D. Pearce, World energy demand and crude oil prices to the year 2000, Annual Conference of the Agricultural Economics Society, Discussion paper 80-12, Aberdeen University, 1981. [3] C. Flavin and N. Lenssen, Power Surge, W.W. Norton and Company,New York, 1994. [4] H. Nazer, Oil producers challenges into the 21st century, Second International Conference on Catalysts in Petroleum Refining and Petrochemical Industries, KISR, Kuwait, 1995. [5] T. Temperley,Commentary,IDA News, 3(3/4) 1994. [6] P.J.W.O'Meara, A 20 years hindsightof OSW's two decades of progress, The International Desalination and ReuseQuarterly,2(2) 1992, 2(3) 1992. [7] M.AK. AI-Sofi and E.A.F. As-Sayed, Available aspects for research and study for developingmultistage flash distillation, Proc., Second Gulf Water Conference,Bahrain, 5-9 Nov. 1994,2 (1994) 216 (in Arabic). [8] MiddleEast Multilateral Working Group on Water Resources (MEMWG), Sultanate of Oman WorldWide Desalination Research and Technology Survey, The Ministry of Foreign Affairs, Sultanate of Oman, 1994. [9] J.A.Dracup and J. Glarer,Desalination: The need for AcademicResearch,Submissionto the US House of Representatives Committee on Science Space and Technology, Subcommittee on Science, July 17, 1991, WashingtonDC, US Congress. [10] G.F.Leitner,Commentary,IDA News, 3(5/6) 1994. [11] W.T. Hanbury, Contributions that Chemistry and Chemists Can Make to DesalinationTechnology,An Engineers View, Department of Mechanical Engineering,Universityof Glasgow, Scotland,UK, 1994. [12] R.D.G. Pyne, GroundwaterRecharge and Wells, A Guide to Aquifer Storage Recovery, Lewis Publishers, 1994. [13] P.C. Singer, R.D.G. Pyne, A.V.S. Mallikatjun, C.T. Miller and C. Mojonnier, Examining the impact of aquifer storage and recovery on DBP's, J. AWWA, 1993. [14] R.D.G. Pyne, Aquifer storage recovery (ASR): ensuring water supply reliability for the Gulf region, Proc., First Gulf Water Conference, Dubai, 1 (1992).