COMPLEX EVALUATION OF WATER SUPPLY AND SEWERAGE SYSTEMS

нженерн системи та техногенна безпека

Випуск 2009 2(76)

УДК 628.1

N. G. NASONKINA, V. N. SAKHNOVSKAYA

Donbas National Academy of Civil Engineering and Architecture

COMPLEX EVALUATION OF WATER SUPPLY AND SEWERAGE SYSTEMS

Different methods of water quality appraisal have been analyzed. Necessity of creation of a single integralparameter of water quality for water supply and sewerage systems has been proved. The model of a complexevaluation of the condition of water supply and sewerage systems has been developed taking into accountecological and economic risk and being significant in case of the urgent necessity to eliminate the negativechanges in the system and in case of developing the program of measures focused on increase of the reliabilityof water supply and sewerage systems of cities and towns.

water quality appraisal, reliability, water supply, sewerage, sewage treatment plants; sewage, ecologicalsafety, integral index, chemical contamination, biological contamination

Problem statement. Operational control of the processes of assurance of reliability of water supply andsewerage systems often presents problems of choice of management decisions under the conditions of quickand deep changes of the factors affecting water (or sewage) supply to end users (or to sewage treatmentplants) in the ordered quantity and of optimal quality. The monitoring data is not enough for objective andoperational response to negative changes of these factors. Great significance has possibility of quick overviewof potential scenarios of development of crisis situations and choice of the most suitable (as per economicand ecological features) variant of management decisions.

A lot of hydro chemical, bacteriological and physical and chemical parameters that characterize itscontamination are defined in the process of quality control of natural water, drinking water and sewage.However, it is necessary to make integral evaluation of water supply and sewerage systems as per allmeasured parameters. Common approach to water quality definition by the way of comparison ofconcentration of contaminants in the water with the normative doesn't give clear idea of total contaminationand possibility of risk in the system, first of all, because of absence of comparability of separate parameters.Overview of the last researches and publications. The prediction of the condition of water supply andsewerage systems should be done as per all rated parameters.

A method of expert evaluations is often used to get quantitative characteristics of water quality by а set ofparameters [1, 2]. The main disadvantage of this method is that stated in it absolute values change step like, i.e. influence of the contaminants on the quality of water has multi steps character.

Integral parameter of water quality that is proposed in the assignment [3] considers the significance ofconcentration variations depending on water content. It is necessary to note that isolated appraisal of waterquality in absolute or relative values often not fully describes condition of water resource potential of thesystem.

By today different methods of complex evaluation of surface water contamination have been developedand used, generalized numeric characteristics of water quality are defined there by all or some mainparameters and by kinds of water use as well. Overview of existing parameters of water quality appraisal [4,5] shows that in order to get a more detailed view of contamination of different sections of water ponds itis necessary to use complex index of water quality or index of contamination degree by toxic substances;for preliminary evaluation — index of chemical contamination level, combination index of contamination,coefficient of contamination or generalized index of contamination level; for evaluation and comparison ofcontamination changes on different sections of water flow — index of chemical contamination level; forcomparative appraisal of water quality within the same water flow or region index of contamination level isthe most preferential.

© N. G. Nasonkina, V. N. Sakhnovskaya, 2009

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