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Reuse of greywater in Kuwait A. Abusam

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Water Resources Division, Water Technologies Department , Kuwait Institute for Scientific Research , PO Box 24885, Safat 13109, Kuwait Published online: 19 Feb 2008.

To cite this article: A. Abusam (2008) Reuse of greywater in Kuwait, International Journal of Environmental Studies, 65:1, 103-108, DOI: 10.1080/00207230701868204 To link to this article: http://dx.doi.org/10.1080/00207230701868204

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International Journal of Environmental Studies, Vol. 65, No. 1, February 2008, 103–108

Reuse of greywater in Kuwait A. ABUSAM Water Resources Division, Water Technologies Department, Kuwait Institute for Scientific Research, PO Box 24885, Safat 13109, Kuwait Taylor and Francis Ltd GENV_A_286991.sgm

(Received 17 December 2007)

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International 10.1080/00207230701868204 0020-7233 Original 0Taylor 00 [email protected] A.ABUSAM 2008 00000&Article Francis (print)/1029-0400 Journal of Environmental (online) Studies

Wastewater reuse is an important element of Kuwait’s water management system because fresh water is scarce and seawater desalination is expensive. Kuwait reuses a significant portion of treated ordinary domestic wastewater, mainly in irrigation of fodder crops and landscapes. Greywater usually represents a major part (50–80%) of domestic wastewater. More importantly, greywater can be treated and reused much more easily than ordinary domestic wastewater. Yet, reuse of greywater is not common in Kuwait. This paper describes the current situation of greywater reuse in Kuwait and discusses the potential for greywater reuse in Kuwait. Keywords: Wastewater; Greywater; Treatment; Reclamation; Reuse; Recycling

1. Introduction Kuwait is situated in an extremely arid area with a harsh climate. The climate of Kuwait is characterized by high temperature, a high evaporation rate and little rainfall which varies somewhat from year to year. The maximum daily temperature in summer can reach 50°C. While the rainfall is only about 140 mm/year, on average, the evaporation rate is about 12 mm/day [1]. Thus, annual evaporation is much higher than annual rainfall. Natural fresh water resources available to Kuwait are limited to small amounts of brackish ground water, which are used mainly for non-potable household uses, and for irrigating landscapes and public parks. For a long time, therefore, Kuwait has been completely dependent on the desalination of seawater to satisfy the potable water demands of both domestic and industrial sectors. In the last two decades, water demand in Kuwait has increased sharply (figure 1) due to the rapidly growing population, urbanization and agricultural activities. In fact, the per capita consumption rate of water in Kuwait (>500 l/c.d) is one of the highest in the world [2]. In Kuwait, water is consumed primarily by the agricultural sector, which consumes about 60% of the total available fresh water. The domestic and industrial sectors consume 37% and 3%, respectively [3]. Thus, the agricultural sector is the major consumer of water in Kuwait although its contribution to Kuwait’s economy is very small. Agriculture and fisheries combined account for only 0.5% of the county’s gross domestic product (GDP). Corresponding author. Email: [email protected] International Journal of Environmental Studies ISSN 0020-7233 print: ISSN 1029-0400 online © 2008 Taylor & Francis http://www.tandf.co.uk/journals DOI: 10.1080/00207230701868204

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A. Abusam

Average Daily Consumption [Million cubic meter]


1 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 1988

Figure 1.

Brackish water Potable water

1990

1992

1994

1996 Year

1998

2000

2002

2004

Average daily consumption of water in Kuwait [1].

Due to the high depleting rates of brackish water resources and the high costs of seawater desalination, treated wastewater has become an important alternative water source for Kuwait. The country’s 1990–2015 Agricultural Master Plan treats wastewater as a feasible option for irrigation and greenery [4]. At present, more than 33% of the wastewater treated at the main municipal wastewater treatment plants is used to irrigate fodder crops, landscape areas and date palms [5]. Municipal wastewater treatment plants in Kuwait treat either to tertiary level, using sand filtration and chlorination, or to an advanced level, using ultra filtration (UF) and reverse osmosis (RO). To date, both tertiary and advanced effluents are used mainly in the irrigation of fodder crops. Domestic wastewater is often categorized as either blackwater or greywater. Blackwater is toilet wastewater arising from toilets, urinals, and/or bidets and, thus, is highly contaminated with faeces or urine. On the other hand, greywater, or sullage, is the non-toilet wastewater that arises from hand basins, showers, baths, clothes-washing machines, dishwashing machines, and/or kitchen sinks. Being non-toilet waste, greywater is not grossly contaminated by faeces or urine. All types of greywater can, however, have some faecal contamination [6]. The highest faecal contamination is usually in shower and bathroom wastewaters. A large portion (50–80%) of domestic wastewater is usually greywater, which is generally less polluted than other types of wastewater [7,8]. Greywater can be treated and reused much more easily than domestic wastewater. Simple low-cost treatment technologies are often sufficient, and can be limited to primary and/or secondary conventional treatment levels – with or without disinfection [9]. The important benefit of greywater reuse is the conservation of potable water resources. Several reuse options exist. In households, for example, treated greywater can be reused in toilet flushing, garden irrigation, yard watering, car washing, and clothes washing. Savings in potable water due to the reuse of greywater in toilet flushing alone can be 30–40% in households and 60–70% in commercial buildings [10]. Other benefits of greywater reuse

Figure 1. Average daily consumption of water in Kuwait [1]

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include reduction of wastewater treatment costs, relief of wastewater treatment plants from organic and hydraulic overloads and use of otherwise wasted nutrients (i.e. nitrogen, phosphorus and potassium). This paper describes the current situation of greywater reuse in Kuwait. It also presents the research work carried out by the Kuwait Institute for Scientific Research (KISR) and discusses the potential for and constraints on greywater reuse in Kuwait.


2. Present situation of greywater reuse Reuse of greywater (i.e. non-toilet wastewater) is based on separating it from blackwater (i.e. toilet wastewater). This requires a dual plumbing system for separate collection of the two. The plumbing system widely used in Kuwait is, unfortunately, a single system. Thus, reusable greywater streams in Kuwait are only from laundry and kitchen. Generally, these wastewater streams can be easily separated from other wastewater streams. That is why some householders in Kuwait attempt to bucket these greywater streams and use them to water their gardens. Such unregulated greywater reuse is often carried out without any treatment, despite the associated public and environmental health risks (see later). This practice is limited to a few people in Kuwait. Other greywater uses, such as toilet flushing, are generally not practised in Kuwait. Kitchen and laundry wastewaters (i.e. dark greywaters) are usually heavily polluted, and therefore, it is recommended that they be treated separately or with blackwater. In general, kitchen wastewater is heavily polluted with food particles, cooking oils and fats, detergents, and dishwashing powders. Food particles and oils can solidify, and consequently, block the irrigation system. Fats usually promote the growth of micro-organisms and, thus, increase health risks. Detergents and cleaning products can harm soils, plants and ground water. Furthermore, kitchen wastewater can contain faecal contamination (i.e. bacteria and viruses) [6]. Adequate treatment of kitchen wastewater before reuse is, therefore, essential. Laundry wastewater can also contain faecal and chemical contaminations (i.e. bacteria, viruses and toxic chemicals). Chemical contamination of laundry wastewater with residues from soap powders, bleaches and disinfectants, and soiled clothes is detrimental to soils and plants due to their high salinity, alkalinity and pH. Also, hot laundry water can injure plants and kill beneficial soil micro-organisms. Therefore, it is often recommended that laundry wastewater be cooled before reuse. There have been only two documented studies carried out by the Kuwait Institute for Scientific Research (KISR). The first is a proposal for the treatment and reuse of ablution water generated at the largest mosque in Kuwait in combination with brackish water [11]. Preliminary treatment processes and reverse osmosis membrane (RO) filtration were proposed for treating both the ablution and brackish waters. The treated waters thus were then proposed to be used for irrigating the gardens of the mosque. Preliminary quality analyses of the ablution water and brackish water were conducted, but there has been no action on this proposal. The second study is a preliminary survey aimed at estimating the generation rates for household wastewater streams in Kuwait in order to enable future assessment of the potable-water savings-potential of greywater reuse [12]. The frequency and duration of use of sanitary appliances (e.g. hand wash basins, toilets and clothes washing machines) were monitored for a month in three houses located in three different places in Kuwait. The residents of the selected households were provided with special forms to record the frequency and duration of use of

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A. Abusam Table 1.

Contribution of blackwater and greywater to total household wastewater [12].

Household


1 2 3

Blackwater (%)

Greywater (%)

Total generated household wastewater (L/c.d)

13.73 18.31 13.28

86.27 81.69 86.72

459.66 213.89 457.54

all sanitary appliances. Using the information gathered from the mini-survey, total household wastewater and generation rates for the various blackwater and greywater streams were estimated. The results obtained (tables 1 and 2) indicated that greywater represents about 85% of the total household wastewater, and about 84% of the greywater (i.e. 71% of total the household wastewater) is light greywater (i.e. coming from showers and hand basins). From this study, it seems that Kuwait has a very high potable-water saving-potential from greywater reuse. But because of the limited scope of this study, a more detailed study is urgently needed to investigate greywater generation rates in Kuwait.

3. Potentials of greywater reuse Although there are several benefits from greywater reuse, the discussion here will be limited to only the conservation of potable water resources and savings in wastewater treatment costs. According to Al-Rashidi and Shahalam [13], Kuwait generates about 0.5 million m3/d of domestic wastewater per day (183 million m3/year). For the sake of illustration, let us use the 85% greywater generation rate estimated by Abusam et al. [12] for Kuwait in the preliminary study described above. Further, let us assume that only half of the available greywater is reused. Thus, about 90 million m3 of potable water can be saved annually. That is to say, 30% or more of the domestically consumed water can be saved through the reuse of greywater. Let us assume that all reused greywater (i.e. 30% of domestic water) will be used only at household and community levels. That is, none of it will reach the central wastewater treatment plants. The amount of wastewater treated at the central plants will then also be reduced by 30%. Such a huge reduction of wastewater loads on the treatment plants can mean improved treatment and significant savings in capital (i.e. building new plants or expanding existing ones) and operational (i.e. pumping energy, aeration and chemicals) costs of wastewater treatment. The cost of greywater treatment is usually less than that for ordinary domestic wastewater. For simplicity, let us assume that the treatment cost of greywater in Kuwait is about half the treatment cost for ordinary domestic wastewater, which is 1.75 U$D/m3. On these assumptions, Kuwait can save about 78.75 million U$D annually. Table 2. Household 1 2 3

Contribution of greywater streams to total household wastewater [12].

Shower and hand basins wastewater (%)

Kitchen wastewater (%)

Laundry wastewater (%)

71.30 66.00 75.77

13.87 13.91 9.29

1.10 1.78 1.67

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4. Constraints for greywater reuse As in other countries in the region, there are several legal, financial and social constraints for greywater reuse in Kuwait. First, there are no standards or guidelines for greywater reuse in Kuwait. To promote greywater reuse in the country, standards and guidelines must first be developed or adapted from other countries where they are in use. Alternatively, in the absence of national guidelines, the recently published WHO guidelines may also be used [14]. Second, single plumbing systems currently used all over Kuwait will not permit implementation of greywater reuse schemes. Reuse of greywater is based on exclusion of blackwater. A dual plumbing system is thus indispensable. Because Kuwait is a highly urbanized country and the major part of its urban development has been completed, implementation of a dual plumbing system all over Kuwait could be difficult. With political will and economic incentives, however, dual plumbing system could be used all over Kuwait. Finally, cultural barriers will probably limit the wide-scale acceptance and participation of the public in greywater reuse schemes. As in other Islamic countries, in Kuwait there is generally a negative attitude towards wastewater reuse. Some people think that reusing wastewater is contrary to Islam, and for that reason, they do not accept the idea of reusing any type of wastewater. In fact, this is not true since Islam allows the reuse of adequately treated wastewater [15]. To change this negative attitude, people need to have a clear understanding of the quality of all types of treated wastewater, including greywater, and their intended applications. This matter requires education by the educational system, endorsement by decisionmakers, and popular concern to creative a receptive attitude instead of a negative one. 5. Future research opportunities Little research work has been done in Kuwait on greywater, and none has been implemented. Therefore, much academic work needs to be done in Kuwait in all aspects of greywater reuse: technical, environmental, economical and social. The fundamental reason for the very limited interest in greywater reuse in Kuwait would appear to be with the high levels of wealth enjoyed by all residents of Kuwait. Therefore, there is no apparent reason why economy should be practised in husbanding the irreplaceable resources of water. It is not perceived to be a serious question. There is no economic incentive to change. There is no particular concern with environmental issues to support the argument for change. 6. Conclusions Reuse of greywater in Kuwait is negligible. Economic and political considerations may well lead to a change in this respect, if questions related to depleting oil reserves and investment in a secure future can be related to the facts of water shortage and the actual costs of desalination. References [1] Ministry of Planning, 2004, Annual Statistical Abstract (Kuwait: Ministry of Planning). [2] Ministry of Energy and Water, 2002, Statistical Year Book: Water 2001 (Kuwait: Ministry of Energy and Water). [3] World Bank, 2005, A water sector assessment report on the countries of the Cooperation Council of the Arab States of the Gulf, Report No. 32539-MNA.


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[4] Razzaque, M.A., Malik, R., Ibnoaf, M., Abbas, S., Al-Khozam, N. and Al-Mutawa, T., 1990, Master plan for development of Kuwait’s agricultural sector (1990–2015), Report No. 4615, Kuwait Institute for Scientific Research, Kuwait.. [5] Shammari, S. and Shahalam, A., 2005, Wastewater demand and wastewater management in Kuwait, in: Proceedings of 7th Gulf Water Conference, Kuwait,. pp. 701–710. [6] Ledin, A., Eriksson, E. and Henze, M., 2001, Aspects of groundwater recharge using greywater, in G. Lettinga (Ed.) Decentralised Sanitation and Reuse (London: IWA). [7] Eriksson, E., Auffarth, K., Henze, M. and Ledin, A., 2002, Characteristics of greywater, Urban Water, 4(1), 85–104. [8] Mullegger, E., langergraber, G., Helmut, J., Starkl, M. and Laber, J., 2003, Potentials for greywater treatment and reuse in rural areas, in: Proceedings of 2nd International Symposium on Ecological Sanitation, Luebeck, Germany,. pp. 799–802. [9] Jefferson, B., Laine, A., Parsons, S., Stephenson, T. and Judd, S., 1999, Technologies for domestic wastewater recycling, Urban Water, 1, 285–292. [10] Lazarova, V., Hills, S. and Briks, R., 2003, Using recycle water for non-potable, urban uses: a review with particular reference to toilet flushing, Water Science and Technology, 3(4), 69–77. [11] Hadi K, Al-Mutairi, N. and Wazzan, Y., 2004, Preliminary study on treatment and reuse of greywater and brackish water at Kuwait’s largest mosque (Kuwait: Kuwait Institute for Scientific Research), Proposal, Kuwait (in Arabic). [12] Abusam, A., Al-Naser, H. and Safar, H.M., 2007, Greywater generation rates and potentials for potable water saving at household level in Kuwait, in: Proceedings of 8th Gulf Water Conference, Kuwait,. pp. 68–80. [13] Al-Rashidi, H., Shahalam, A. and Alam, S., 2005, Centralized management of treated wastewater reuse in Kuwait – collection, storage and distribution, in: Proceedings of 7th Gulf Water Conference, Kuwait,. pp. 633–643. [14] WHO, 2006, Use of Wastewater, Excreta and Greater (Geneva: World Health Organization). [15] Faruqui, N.I., 2006, Wastewater treatment and reuse for food and water security, RUAF Magazine, 8, http:// www.ruaf.org/no8/20_mena.html, Accessed 16 January 2008.