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Über dieses Buch

This book brings together and integrates contributions on water quality modeling, monitoring and assessment techniques; wastewater treatment technologies; and sociological approaches in a single text. Divided into twenty chapters, it offers a comprehensive reference for students, professionals and researchers working on various aspects of water environment technology.
The papers published in this book – selected from those presented at the 1st International Forum on Asian Water Environment Technology, held in 2013 in New Delhi, India – highlight the water environmental problems in Asia and respective countermeasures. This book addresses water quality requirements, emphasizing the factors that affect the water environment. Treated wastewater as a new source of water is also examined, introducing readers to important aspects of water reuse. Selecting the most effective and proper wastewater treatment approach is actually the most essential part of generating a new water resource, as well as protecting the receiving water environments. Thus, the fundamental principles of wastewater treatment and monitoring are a major focus in this book, which is intended to help readers effectively address various water environmental problems in Asian countries.



Wastewater Treatment and Monitoring: Physico-Chemical Treatment


Chapter 1. RSM and ANN-GA Experimental Design Optimization for Electrocoagulation Removal of Chromium

The present study was aimed at optimizing electrocoagulation removal of hexavalent chromium using iron electrodes. Process variables investigated were chromium concentration, pH, current density (or voltage) and treatment time, and the responses measured were chromium removal efficiency and energy consumption. Using the experimental results, the treatment process was modeled by response surface methodology (RSM) and by artificial neural network-genetic algorithm (ANN-GA). The optimum current density for energy efficient chromium removal was found to be 20–40 A/m2 for treatment time of 10 min. Current density beyond the optimum range had a cascading effect on chromium removal efficiency.
Manpreet S. Bhatti, Ashwani K. Thukral, Akepati S. Reddy, Rajeev K. Kalia

Chapter 2. Sunlight-Assisted Photo-Fenton Process for Removal of Insecticide from Agricultural Wastewater

Pesticides and insecticides are harmful and toxic organic chemicals that are used for controlling pests and insects in agriculture, thereby considered as necessary evil. Agricultural wastewater, contaminated with such toxic pesticides, pollutes surface and groundwater. Pesticides are able to reach surface waters either directly or indirectly via the discharge of agricultural drainage water from treated land and via runoff after application on hard surfaces (Leu et al. 2004). Organophosphorus pesticides are produced in mass and are widely used in the developing country. 2,2 dichlorovinyl dimethyl phosphate, commonly referred as Dichlorvos (Fig. 2.1) is an organophosphorous insecticide, which is highly toxic, non-biodegradable and difficult to remove by conventional methods. During 2006–2010 period, consumption of Dichlorvos in India was 5833 metric tons. Due to its fairly good solubility [~10 g.L−1 (at 20 °C)] in water (WHO 1978, 1994) it is highly mobile in aquatic environment. Various technologies and processes have been proposed for the treatment of pesticide-contaminated waters. Some conventional techniques including flocculation, filtration and adsorption of activated carbon are only based on a phase transfer of the pollutant. These treatment procedures are either of high cost or a source of secondary pollution due to sludge formation: therefore, there is a need to seek better alternatives (Evgenidou et al. 2005). Advanced oxidation processes (AOPs) are attractive methods for the treatment of wastewaters containing refractory organics due to their efficiency to oxidize a great variety of organic contaminants by the generation of highly reactive hydroxyl radicals (OH•) (Espulgas et al. 2002). Many pollutants, including pesticides, pharmaceuticals and dyes can be completely mineralised by AOP as reported in the works of Chiron et al. (2000), Perez-Estrada et al. (2005) and Lucas and Peres (2006). Heterogeneous photocatalysis using titanium dioxide (TiO2) and solar/UV radiation, combined with hydrogen peroxide (H2O2), and homogeneous processes such as Fenton (Fe2+/H2O2) and photo-Fenton (Fe2+/H2O2/UV/sunlight) reactions are proved to be useful techniques for the treatment of pesticide-contaminated wastewater. There are different ways to produce HO•, among which solar photo-Fenton process is one of the most efficient ones for the treatment of contaminated wastewater (Malato et al. 2002; Oller et al. 2006; Maldonado et al. 2007; Ortega-Liébana et al. 2012; Klamerth et al. 2013).
Amrita Dutta, Sanjukta Datta, Mahua Ghosh, Debasish Sarkar, Sampa Chakrabarti

Chapter 3. Catalytic Reduction of Water Contaminant ‘4-Nitrophenol’ over Manganese Oxide Supported Ni Nanoparticles

Nitroaromatic compounds (NACs) are among the largest and most important groups of industrial chemicals in use nowadays (Ju and Parales 2010; Tomei et al. 2010). The NACs, such as nitrophenol, nitrobenzene, nitrotoluene, and nitrobenzoates, are of considerable industrial importance as the main raw materials in the manufacture of various dyes, pharmaceuticals, pesticides and explosives (Tomei et al. 2010; Yi et al. 2006; Aditya et al. 2015). 4-Nitrophenol (4-NP) is one of the most common and important NACs, both in terms of quantities used and potential environmental impacts (Yi et al. 2006; Podeh et al. 1995; Aditya et al. 2015; Sarkar et al. 2011). 4-NP is mainly used for the manufacture of drugs (e.g. acetaminophen) and pesticides (e.g. methyl and ethyl parathion) and is also used in leather treatment, in dyestuff production, and for military purposes. Because of its regular and extensive use, 4-NP can be found as a pollutant in industrial wastewater streams associated with its formulation, distribution and application (Yi et al. 2006; Pozun et al. 2013). Moreover, hydrolysis of pesticides and herbicides can also release 4-NP into the subsurface and then contaminate groundwater resources (Labana et al. 2005). As the 4-NP released into the environment, its contamination can cause a significant environmental and public health risk, due to its acute toxicity and mutagenic potential (Yi et al. 2006; Podeh et al. 1995; Labana et al. 2005; Aditya et al. 2015; Pozun et al. 2013). The acute exposing of 4-NP may lead to blood disorders along with methemoglobin formation, liver and kidney damage, anemia, skin and eye irritation, and systemic poisoning. In particular, it may cause deleterious effects to ecological systems, due to the 4-NP contamination of rivers and groundwater resources [Zieris et al. (1988), Aditya et al. (2015)]. Therefore, 4-NP containing industrial wastewater should be uncontaminated before being discharged into the environment.
Pangkita Deka, Debajyoti Bhattacharjee, Pingal Sarmah, Ramesh C. Deka, Pankaj Bharali

Chapter 4. Simulation of Nitrate Removal in a Batch Flow Electrocoagulation-Flotation (ECF) Process by Response Surface Method (RSM)

Electrocoagulation-flotation (ECF) is one of the newest treatment methods, which has been used successfully to remove different kinds of pollutants (Behbahani et al. 2013). ECF is a process which consists of three main parts: (1) Creating metallic hydroxide flocs within the solution by electro-dissolution of soluble anodes, (2) Formation of coagulants in aqueous phase, and (3) Adsorption of pollutants on coagulants and then removal by sedimentation/flotation (Arroyo et al. 2009; Zaroual et al. 2009).
E. Nazlabadi, M. R. Alavi Moghaddam

Wastewater Treatment and Monitoring: Biological Treatment


Chapter 5. Decolourization Studies of a Novel Textile Dye Degrading Bacterium

Textile dyes represent one of the most complicated pollutants because of their complex nature and difficulty in degradation. More than 100,000 commercially available dyes are known and the world annual production of the dyestuffs amounts to more than 7 × 105 tonnes (Robinson et al. 2001). It has been estimated that more than 10–15 % of the total dyestuff used in dye manufacturing and textile industry is released in to the environment during their synthesis and dyeing process. Almost 2,80,000 tonnes of textile dyes are discharged every year worldwide (Mass and Chaudhari 2005). In India, annual consumption of dyes by the textile industries is around 6,01,225 tonnes. The release of textile dyes into the environment is of great concern due to colourations of natural waters and also due to toxicity, mutagenicity and carcinogenicity. Various physical and chemical treatment methods are available for colour removal but use more energy and chemicals than biological processes. Moreover, they also concentrate the pollution into solid or liquid sidestreams requiring additional treatment or removal. Therefore, biological treatment is often the most economical alternatives when compared with other physical and chemical processes (Solis et al. 2012). However, it is considered that due to the recalcitrant nature of the textile dyes, the textile wastewaters impart toxicity to the microorganisms making aerobic treatment difficult. On the other hand, treatment under anaerobic conditions (by using anaerobic bacteria like Bacteroids sp., Eubacterium sp., Clostridium sp. etc.) produces aromatic amines which are toxic to the environment (Archna Lokesh and Siva Kiran 2012).
S. Menaka, S. Rana

Chapter 6. Preliminary Study of Rapid Enhanced Effective Micro-organisms (REEM) in Oil and Grease Trap from Canteen Wastewater

Characteristics of canteen wastewater and other commercial food service facilities differ significantly from residential wastewater. Due to its high amount of organic matter, oil and grease and suspended solids, it causes higher biochemical oxygen demand (BOD). Oil and grease present in a form of low-biodegradable and frequently cause problems for both on site sewage disposal systems and public sewer systems. The water in contact with the free oil and grease (FOG) had high levels of oil approximately 800 mg/L and this may indicate the poor FOG management practices (Williams et al. 2012). Oil and grease in wastewater can exist in several forms: free, dispersed or emulsified. The differences are based primarily on size. In an oil-water mixture, free oil is characterized with droplet sizes greater than 150 μm in size while dispersed oil has a size range of 20–150 μm and emulsified oil has droplets typically less than 20 μm (Hu 2002). The majority of oil in canteen wastewater is free oil which can be removed by an overflow weir grease trap (Pollution Prevention Regional Information Center 2014). A grease trap is a chamber designed for wastewater pass through and allow any free or mechanically emulsified oil to float to the surface. Then clear wastewater can be treated in the next wastewater treatment unit. Although grease trap tanks are supposed to prevent oil and grease to enter the sanitary sewer line, high grease loads, emulsified grease, and surge wastewater loadings often cause oil and grease bypass the grease trap tanks. Some researchers found that grease trap tanks showed the removal efficiency between 43 and 80 % (Wong et al. 2007; Wongthanate et al. 2014).
T. Kornboonraksa

Chapter 7. Step-Feed Technology in SBR to Enhance the Treatment of Landfill Leachate

Municipal solid waste leachate is the liquid leached from a landfill. The annual production of municipal solid wastes in Sri Lanka, is mostly disposed via landfilling or open dumping. The generation of leachate is caused principally by precipitation, percolating through waste deposited in a landfill. Once in contact with decomposing solid waste, the percolating water becomes contaminated and if it then flows out of the waste material, it is termed leachate. This leachate (if not collected and treated) poses dangerous environmental and health risks due to its impact on surface and ground waters. Leachate may contain large amounts of organic matter (biodegradable, but also refractory to biodegradation), where humic-type constituents consist as the important group, as well as ammonia-nitrogen, heavy metals, chlorinated organic and inorganic salts (Renou et al. 2008). It is very costly to clean up when they contaminate the groundwater. Figure 7.1 shows a typical municipal landfill.
K. B. S. N. Jinadasa, T. I. P. Wimalaweera, H. M. W. A. P. Premarathne, S. M. A. L. Senarathne

Chapter 8. Response Surface Optimization of Phosphate Removal from Aqueous Solution Using a Natural Adsorbent

Phosphorous exists in the form of orthophosphate, polyphosphates, pyrophosphate, organic phosphate esters and organic phosphonates, and all these forms could be hydrolyzed to orthophosphate (Majed et al. 2012). Orthophosphate could be utilized by microorganisms, plants and animals for their growth and development. Hence, considered as a vital nutrient in most of the ecosystems and due to its low concentration occurrence in the environment, it usually serves as the limiting nutrient (Huang et al. 2013). Sustained inputs of phosphate (more than 1 mg L−1) to aquatic environments lead to increased rates of eutrophication affecting the quality of domestic, industrial, agricultural and recreational water resources. Then again, phosphorous is an important element, extensively contributing towards many biological, agricultural, industrial, environmental, medical and household applications. Therefore, the excess discharge of phosphates to aquatic environments is taking place through various anthropogenic activities such as the use of fertilizers, pigments, detergents and electronic industry discharge, domestic wastewater discharge, mineral processing, rural and urban sewage disposal etc. (Wang et al. 2013). Excepting eutrophication, the increasing loads of phosphates in water bodies stimulate the activity of a damaging microbe known as , speed up the production of microsystin, a toxin that poisons aquatic animals and can cause hepatocellular carcinoma in humans, and result in depletion of desirable flora and fauna (Yuan et al. 2006; Rout et al. 2015a). In order to prevent these problems phosphorous removal from wastewater is highly desirable before discharging. The World Health Organization (WHO) recommended a maximum discharge limit of phosphorous as 0.5–1.0 mg L−1 (Galalgorchev 1992). Therefore, in the current scenario, more and more stringent regulatory limits of phosphate discharge have been set by many nations and regions worldwide.
Prangya Ranjan Rout, Puspendu Bhunia, Rajesh Roshan Dash

Chapter 9. Removal of Pharmaceuticals from Water Using Adsorption

Drinking water should be free from any kind of contamination. The source of water can be surface water or groundwater. The conventional water treatment plant takes care of most of the organic contaminants and pathogens. However, analysis of water samples by various researchers showed that the water bodies are contaminated with more complex compounds which are toxic at very low concentrations. Extensive research on these compounds started in mid 1990s with the use of more sophisticated instruments (Santos et al. 2010). These compounds are known as emerging contaminants (ECs) which are widely being studied because of their potential to cause long-term effects to living organisms. Even at very low concentration (μg/L to ng/L), these compounds have very high hazard quotient. Many studies have reported the presence of ECs in surface water and ground water. There is lack of knowledge of their impact in long-term effect on human health, environment and aquatic environments (Deblonde et al. 2011).
V. Arya, Ligy Philip

Hydrological and Quality Issues: Surface Water


Chapter 10. Hydrological Regimes and Zooplankton Ecology at Tempe Floodplains, Indonesia: Preliminary Study Before the Operation of the Downstream Barrage

Floodplain is one of a very productive ecosystems (Ning et al. 2013) and harbours high biodiversity of micro-invertebrate (Shiel et al. 1998). Flood and drought cycles induce high biodiversity, and thus productivity, in the floodplain systems where connectivity between terrestrial and aquatic component plays an important role (Schöll et al. 2012; Armitage et al. 2003). Floodplain ecosystem features a network of riverine, and ditches habitats (Armitage et al. 2003), where flood events form a large inundated area by which the terrestrial and aquatic ecosystems are connected. During drought phase, habitats in riverine-floodplain systems are fragmented and isolated from the main river channel forming distinct habitats with distinctive abiotic and biotic characteristics (Thomaz et al. 2007). As opposed to dry condition, floods will reconnect the fragmented habitats, allowing the connectivity between riverine and floodplain systems; and reduce spatial variability within patchy habitats which are formed during low water period. A number of studies suggest that increasing water level during floods event results in increasing similarity between habitats as the connectivity established (Thomaz et al. 2007; Tockner et al. 2000). It is clear that hydrological regime is the key driving force of ecological function and biodiversity in floodplain systems. There have been little study conducted about zooplankton from the floodplain of tropical regions, especially, Indonesia, one of the world’s biodiversity “hotspots”. This preliminary study has, therefore, summarised the diverse assemblages of zooplankton of Lake Tempe as a response to changing water level during dry and flood seasons. Planktonic organisms, including zooplankton, are the key elements in the aquatic environment (Palmer and Yan 2013). The responses of zooplankton to changing environment due to fluctuated water level are fundamental to our understanding of the dynamic of planktonic organisms in floodplain habitats, mainly where they are moderately or heavily regulated.
Reliana Lumban Toruan, Fajar Setiawan

Chapter 11. Organics and Heavy Metals Content in River Receiving the Effluent of Municipal Landfill Leachate Treatment

Municipal solid waste in Indonesia is commonly disposed in a landfill with leachate treatment facility before the effluent is discharged to river. Sarimukti landfill is located 5 km to the southeast of Cirata Reservoir, covers around 21.2 ha area and accepts municipal solid wastes from cities of Bandung, Cimahi and West Bandung. Cirata Reservoir is one of the cascade reservoirs along Citarum River and the sustainability of Citarum River is important since it is utilised for electricity, water supply, irrigation and also fishery activity for many cities along its catchment area.
Indah R. S. Salami, Dimas K. Rizaldi

Hydrological and Quality Issues: Groundwater Contamination


Chapter 12. Tracing the Significance of River for Arsenic Enrichment and Mobilization

Arsenic contamination of groundwater has been found to be prominent in many of the flood plain regions of the world where recent Holocene sediments are predominant (Berg et al. 2008; Kumar et al. 2010; Shah 2010). Reductive hydrolysis of metal (hydr)oxides, particularly those of Fe has been found to be the dominant mode of As mobilization in groundwater of such regions (McArthur et al. 2001; Smedley and Kinniburgh 2002; Berg et al. 2008; Kumar et al. 2010). Some of the most well known regions with high groundwater As, where the aforementioned conditions have been detected are Bangladesh, India, Vietnam and Cambodia (Bhattacharya et al. 1997; Acharyya et al. 1999; Smedley and Kinniburgh 2002; Ahmed et al. 2004; Berg et al. 2007, 2008).
Manish Kumar, Nilotpal Das, Kali Prasad Sarma

Chapter 13. Evaluation of Groundwater Quality in 14 Districts in Sri Lanka: A Collaboration Research Between Sri Lanka and Japan

Groundwater is an indispensable source of drinking water in many rural communities in the dry zone of Sri Lanka. However in most of the areas in dry zone, many residents suffer from health problems associated with high fluoride concentration in drinking water (Tennakoon 2004). In addition, current medical data of these regions have shown a significant increase of number of patients of Chronic Kidney Disease of Unknown Etiology (CKDu) during the recent past. It is evident with several studies done in recent past that there is an increasing trend on the reporting of patients admitted with CKDu (Bandara 2008; Chandrajith 2010).
S. K. Weragoda, Tomonori Kawakami

Chapter 14. Arsenic Contamination in Groundwater Affecting Holocene Aquifers of India: A Review

Groundwater arsenic (As) contamination have been reported in many parts of the world such as Bangladesh, India, Pakistan, Nepal, China, Hungary, Vietnam, Thailand, Cambodia, Taiwan, Inner Mongolia, Ghana, Egypt, Japan, Argentina, Mexico, USA and Chile (Mandal and Suzuki 2002; Ravenscroft et al. 2009). The mode of occurrence, origin and mobility of As in sedimentary aquifers are influenced by local geology, geomorphology, hydrogeology and geochemistry of sediments (Acharyya et al. 2000; Kinniburgh and Smedley 2001). The upper permissible limit of As in drinking water is 10 μg/l, as per the World Health Organization (WHO 1993), which has been endorsed by Bureau of Indian Standards (BIS 2003).
Babar A. Shah

Chapter 15. Water Quality Evaluation in a Rural Stretch of Tezpur, Assam (India) Using Water Quality Index and Correlation Matrix

Groundwater resources have a major role in ensuring livelihood security across the world, especially in economies that depends on agriculture. In India it is the major source of drinking water in both urban and rural and its importance cannot be over emphasized. It accounts for more than 85 % of the rural domestic water needs, and 50 % of the urban water needs (Ganeshkumar and Jaideep 2011). With an estimated use of 230 km3 of groundwater every year, i.e. more than a quarter of the global level, India is the largest user of groundwater in the world. At present apart from depletion of groundwater level, India is also facing problems regarding the increments of pollutant concentration present in it. In the North Eastern region of India, natural springs and dug wells are the only cost effective viable means of fulfilling the domestic needs for present population. Information on groundwater quality of northeast India is scanty (Suryawanshi et al. 2004). It has been reported that the concentration of fluoride (F), and iron [Fe(II)] in the groundwater is much higher than the permissible limits of drinking water at different areas of Assam (Sushella 2001). Fluoride in the groundwater of Assam has been reported in the range of 5–23 mg/L (Meenakshi and Maheshwari 2006) and iron in the range of 1–25 mg/L (Das et al. 2003; Mahanta et al. 2004). The permissible limit in drinking water is 1–1.5 mg/L for fluoride and 0.3 mg/L for iron (IS 10500 1991; WHO 1993). The iron present in the groundwater causes visible colouration to the water, but fluoride doesn’t impart any colour to the water. Therefore the quality of drinking water is of vital importance for human being, though most consumers are unaware of the various pollutants present in the groundwater.
K. U. Ahamad, N. Medhi, V. Kumar, N. Nikhil

Hydrological and Quality Issues: Water Resource in Changing Paradigm


Chapter 16. Meltwater Quality and Quantity Assessment in the Himalayan Glaciers

Glaciers are the largest reservoir of fresh water on the earth. They play a vital role in the hydrological cycle (Sangewar 2012). Snow field areas of the Himalayan glaciers store about 12,000 km3 of fresh water and are the main source of water for great Asian rivers: Ganga, Brahmaputra and Indus (Cruz et al. 2007). There are approximately 9600 glaciers found in the Indian Himalayan region, covering an area of about 40,000 km2 (Raina and Srivastava 2008). Himalayan glaciers control the global climate change and are considered as a sensitive indicator for climate change (Sharma et al. 2013a). Since last century, majority of the Himalayan glaciers have been retreating significantly due to climate change (Kulkarni and Bahuguna 2002; Kulkarni and Alex 2003; Kulkarni et al. 2005) and effecting the meltwater runoff from the glaciers of Himalaya (Kulkarni et al. 2002). Discharge from the Himalayan glaciers is important for the generation of hydroelectric power, irrigation and drinking water supply (Singh et al. 2006).
Virendra Bahadur Singh, A L. Ramanathan

Chapter 17. Delineation of Point Sources of Recharge in Karst Settings

Karst, a geomorphic landscape that arises from the combination of high rock solubility and well developed subsurface drainage networks on rock types that are easily dissolved by water notably carbonate rocks such as limestone, dolomite or marble (Bretz 1942; Sweeting 1981; Jennings 1985; Palmer 1991, 2007; Bloom 1998; Klimchouk et al. 2000; Gunn 2004; Culver and White 2005; Ford and Williams 2007) and to a lesser extent evaporites such as gypsum, anhydrite and halite (Kozary et al. 1968; Klimchouk 2002; Johnson and Neal 2003; Ford and Williams 2007), constitutes 20–25 % of the earth’s land surface (Ford and William 2007; Bakalowicz 2005). These areas are regraded to represent the earth’s most diverse, scenic and resource-rich terrains with much of their wealth hidden underground including minerals, oil and natural gas, limestone quarries, apart from beautiful housing sites for urban development (Lamoreaux et al. 1993; Schmitz and Schroeder 2006). It is worldwide observed that nearly 40–50 % of the human population utilizes drinking water derived from karst aquifer systems, either directly or indirectly (Cost 1995; Ford and Williams 2007; Cooper et al. 2011; Brinkmann and Parise 2012). However, the unique hydrologic, geomorphologic and hydrogeologic features of karst (White 1988; Ford and Williams 2007; Palmer 2007; Parise and Gunn 2007) make these aquifers more vulnerable to pollution and contaminants (Drew and Hötzl 1999; Böhlke 2002; Parise and Pascali 2003; Bonacci 2004; Kovačič and Ravbar 2005; Ford and Williams 2007; Parise 2010).
Gh. Jeelani, Rouf A. Shah

Chapter 18. Identify the Major Reasons to Cause Vulnerability to Mekong Delta Under the Impacts of Drought and Climate Change

The Mekong Delta lies within the humid tropics, characterized by consistently high mean monthly temperatures (25–29 °C) and high but seasonal rainfall (1200–2300 mm). Discharge of the Mekong River exhibits strong seasonal variation in corresponding rainfalls. The low flow period (December to May) occurs during the dry season and the earliest stages of the wet season. The low rainfall and high evaporation during the annual dry season place constraints on human habitation and activity in the Mekong Delta. Such conditions also give rise to other problems such as salinity intrusion in coastal areas and acidification in ASS (Acid Sulfate Soil) areas. Shorter periods of dryness, which occur during the onset, or toward the end, of the wet season in some years, may also be extremely damaging to newly planted crops (Thuan 2006).
Bui Viet Hung

Chapter 19. Multi-pathway Risk Assessment of Trihalomethanes Exposure in Drinking Water Supplies

Disinfection is the last step in the water treatment processes for the protection of public health. In India, chlorine is used as the primary disinfectant because of its low cost and convenience for application in water purification. However, chlorination results in formation of trihalomethanes (THMs) in drinking water which can pose severe health threat due to their potential carcinogenicity. In recent decades, various epidemiological studies have been conducted to determine the relationship between THMs and different health outcomes e.g., cancers and reproductive outcomes (Hrudey 2009). Llopis-González et al. (2011) suggested that exposure to THMs increase the risk of bladder, colon, rectum, leukemia, stomach and rectal cancers. The results of animal studies have demonstrated that liver, kidney and intestinal tumorigenesis are associated with chronic ingestion of THMs (Yang et al. 2000). Since THMs are the most prevalent and well documented disinfection by product (DBP) compounds in drinking water, they are generally considered as indicators of DBP exposure in epidemiological investigations.
Minashree Kumari, S. K. Gupta

Chapter 20. The Study of Water Losses Using Knowledge Based System Approach

Water represents about 70 % of the whole earth surface yet it is limited in its availability as a freshwater to human benefits. The importance is on freshwater assets since it is freshwater resources that are used for daily usage, agricultural and industrial intentions. According to Hu (2006), freshwater represents about 2.76 % of the total water available on earth. And even with this, it is only less than 1 % which is readily available to be accessed and used by human. About 20 % of the world’s population lack access to safe drinking water and about eighty countries, which inhabitat 40 % of the world’s population are in severe water crisis situation. Non-revenue water (NRW) can be defined as the amount or quantity of lost water starting from the water treatment plant to the consumers. In other words, it occurs within the distribution systems added with amount of water that is authorized to use but not billed.
Nassereldeen A. Kabbashi, Mohd A. Hasif, Mohammed E. Saeed


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