12.3. Economic and Financial Procedures of Drinking Water Treatment Plants
Many factors are involved in analysing the economic and financial aspects of drinking water treatment infrastructure. For example, the water that is used for drinking water treatment plants and for many industries is categorised, according to its source, as upland surface water, lowland surface water, groundwater, brackish well water and seawater. Also scale of plant, level of using technology it shows different features. These characteristics that determine the level of treatment required and thus costs. Nevertheless, basically, the strategies and principles are offered the same approach at the pre-treatment phase for drinking water treatment plants. This procedure is as follows, and then will be discussed in the following this sections.
Priority Level: (in sector or regional level, economies, ecosystems, protection of human health)
Assessment environmental impacts of the project (the following matters description that inspired the project factors into action, driving forces, the project's main goals and objectives, expected positive environmental effects, the project's effects on health, the size of the population benefiting from the project implementation)
Demand analysis (estimated future population served by the project, the estimated drinking water)
12.3.1. Priority level for the drinking water treatment plant
In the pre-treatment phase for drinking water treatment plants should be planned in an integrated manner, taking into account long-term planning needs for the efficient and equitable infrastructure investment. On the other hand integrated water resources management is based on the perception of water as an integral part of the ecosystem, a natural resource and a social and economic good, whose quantity and quality determine the nature of its utilization. To this end, water resources have to be protected, taking into account the functioning of aquatic ecosystems and the perennially of the resource, in order to satisfy and reconcile needs for water in human activities. In developing and using water resources, priority has to be given to the satisfaction of basic needs and the safeguarding of ecosystems (URL 2). Therefore, priority level can be defined activities and processes applied to prevent or minimize hazards occurring. In line with mentioned above requirements, the general objective is to make certain that adequate supplies of water of good quality are maintained for the entire population, while preserving the hydrological, biological and chemical functions of ecosystems, adapting human activities within the capacity limits of nature and combating vectors of water-related diseases (URL 3). In accordance with this purpose, Priority Level for the Drinking Water Treatment Plant - strategic content- includes defining project rationale and objectives.
12.3.2. Assessment of environmental impacts
During construction and start up of the facilities to the Drinking Water Treatment Plants environmental impact assessment provides a systematic process for identifying, describing and evaluating natural and human resources in order to improve decisions about their management. Because apart from the quality and safety of the finished drinking water, numerous other health and environmental protection issues are also evident when considering the impacts of desalination processes. At this stage the qualitative and quantitative data should show that the overall environmental impacts. For example use of land, use of natural resources, use of chemicals, waste generation, emissions, noise, etc. as well as reduction of health risk for population; employment at the plants and poverty reduction impact of the project should be assessed.
12.3.3. Demand analysis for the drinking water treatment plant
The demand analysis is an integral component of the project development cycle. Municipal water demand projections are calculated using the projected populations. Changes in population, income and employment will influence water demands. As population, economic activity, and water use changes, water treatment needs will also change. The domestic water demand category covers number households, household size and its composition; present water use in both peak and nonpeak periods; household income; present prices paid or incurred by households; present quality of services and whether elements (ADB, 1998). The main parameters for demand projections are:
Average household size
Number of households
Type of connection
Changes in household income levels
Changes in cost of water
Factors affecting per capita demand
Size of the city: Per capita demand for big cities is generally large as compared to that for smaller towns as big cities have sewered houses.
Presence of industries.
Habits of people and their economic status.
Quality of water: If water is aesthetically medically safe, the consumption will increase, as people will not resort to private wells, etc.
Pressure in the distribution system.
Efficiency of water works administration: Leaks in water mains and services; and unauthorized use of water can be kept to a minimum by surveys.
Policy of metering and charging method: Water tax is charged in two different ways: on the basis of meter reading and on the basis of certain fixed monthly rate (URL 4).
The influence of the various factors strongly varies from country to country and regions depending on the development level. The International Water Consumption Data (2008) show that this composition which differences between countries with regard to water consumption per person in liters The data are shown in Table 12.2 for a few selected countries and areas.
Table 12.2. Fresh water consumption per person in liters
Per person / Per day (Liters)
Other Asia Pacific
Latin America and Caribbean
The quantity of water account
The quantity of water required for municipal uses for which the water supply scheme has to be designed requires following data:
Water consumption rate(Per Capita Demand in liters per day per head - per capita water use, is usually expressed as gallons of water used per person per day)
Population to be served and;
Quantity= Per capita demand x Population
Water consumption rate
Because there are many factors that affect the demand for water, it is difficult a complete determination of the people's water needs. As a sample frame various types of water demand can be categorized as in the Table 12.3 below (URL 4):
Table 12.3. Water Consumption for Various Purposes
Types of Consumption
Normal Range (lit/capita/day)
Industrial and Commercial Demand
Public Uses including Fire Demand
Losses and Waste
Total consumption is derived by applying the projected population in each consumer category against the projected average consumption level in that consumer category. Average Daily per Capita Demand = Quantity Required in 12 Months / (365 x Population)
Fluctuations in Rate of Demand
If this average demand is supplied at all the times, it will not be sufficient to meet the fluctuations. These may also originate: Seasonal variation; Daily variation depends on the activity; Hourly variations are very important as they have a wide range. So, an adequate quantity of water must be available to meet the peak demand. To meet all the fluctuations, the supply pipes, service reservoirs and distribution pipes must be properly proportioned. The water is supplied by pumping directly and the pumps and distribution system must be designed to meet the peak demand. The effect of monthly variation influences the design of storage reservoirs and the hourly variations influences the design of pumps and service reservoirs. As the population decreases, the fluctuation rate increases (URL 4). Maximum daily demand calculates with the following: Maximum daily demand = 1.8 x average daily demand Maximum hourly demand of maximum day i.e. peak demand can be calculated with the following equation:
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