SELECTION OF WATER TREATMENT PROCESSES Water treatment process

SELECTION OF WATER TREATMENT PROCESSES

ØWater treatment process selection is a complex task. ØCircumstances are likely to be different for each water utility and perhaps may be different for each source used by one utility. ØSelection of one or more water treatment processes to be used at a given location is influenced by the necessity to meet regulatory quality goals, the desire of the utility and its customers to meet other water quality goals (such as aesthetics), and the need to provide water service at the lowest reasonable cost.

Factors that should be included in decisions on water treatment processes include:

Factors that influence the process reliability

Example for eutrophic Lake

Water Quality Models Water quality models can be effective tools to simulate and predict pollutant transport in water environment, which can contribute to saving the cost of labors and materials for a large number of chemical experiments to some degree. Moreover, it is inaccessible for on-site experiments in some cases due to special environmental pollution issues. Therefore, water quality models become an important tool to identify water environmental pollution and the final fate and behaviors of pollutants in water environment. These construction projects such as petrochemical, hydrological, and paper-making projects can bring serious effects on aquatic environment after enforcement. Therefore, these environmental effects have to be simulated, predicted, and assessed using numerical models before these construction projects are implemented.

Table 1: Main surface water quality models and their versions and characteristics

Surface water quality models for rivers, lakes and oceans

Selection of water treatment processes

TREATMENT PROCESS SELECTION The selection of treatment facilities must be determined by feasibility studies, considering all engineering, economic, energy and environmental factors. All legitimate alternatives must be identified and evaluated by life cycle cost analyses.

PROCESS SELECTION FACTOR

Ø Water can be both source of or vector for transmission of pathogens. Therefore, maintaining the microbial quality of water used in both pre- and postharvest processes is of great importance and water disinfection is an efficient tool to ensure water quality. Ø Due to some negative influences of chlorination on health and environment, a. o. harmful disinfection by-products (DBPs), the search for alternative disinfection techniques has notably increased. Ø The aim of the study was to characterize the criteria that influence decision making when assessing possible disinfection technologies in order to prevent produce associated pathogens.

METHODOLOGY The identified selection criteria were divided into three main aspects: technological, managerial, and sustainability.

Ø Defining selection criteria shows that choosing a feasible technique does not only depend on it’s ability to inactivate pathogens in the used water. Ø There are other considerations to be taken into account, such as the integration of disinfection technologies in the whole of the water treatment and the pre- or postharvest practice, assuring a successful and affordable operation and maintaining the disinfection operation, with respect to human health, worker safety and the environment. Ø The defined selection criteria can be applied by the end user as preliminary screening instrument in order to decide which technologies can be subjected to pilot scale tests.