Advances in Water Treatment and Enviromental Management

COST OF DIFFERENT WATER QUALITY PROTECTION POLICIES 27Table 5. Ambient Water Quality Improvement GoalsVIOLATIONS OF AMBIENT WATER QUALITY STANDARDS IN THE STUDY AREAViolation of ambient water quality standards for pollution loads as measured in1978/79 and predicted pollution loads in 1990 are presented in Table 4.The calibrated model was used for simulation of ambient water quality in low-flowconditions for cases:– no waste water treatment,– effects of different degrees of waste water treatment.DEFINITION OF AMBIENT WATER QUALITY PROTECTION POLICIESThe step-wise ambient water quality improvement is accepted as a policy, so thecosts will be more easily met.Ambient water quality goals are listed in Table 5, given as maximum permissibleconcentration (MPC). Complete removal of floating debris, grease and oil as well assubstantial removal of coliforms are anticipated. Implementation of the third degreeof protection ensures the class of stream prescribed by the Regulations. Waterquality of this stream is wholly protected. If the fourth degree of protection isintroduced, some of the river reaches may attain a higher class.BENEFITS OF IMPLEMENTATION OF CERTAIN DEGREES OF PROTECTIONThe benefits to be gained from this step-wise protection of deteriorated ambientwater quality are as follows:First Degree of ProtectionBenefits of the applied first degree of protection are:– water may be used for watering of cattle and irrigation;– WQ in downstream reaches will be improved, with a corresponding benefit tolocal users;– aquatic population is protected;– aesthetic appearance of the stream and environment will be improved;– better situation in the water supply system located further downstream, eitherin the case of direct intake, or in the case of infiltration basins/ground wateraquifer use.Second Degree of ProtectionBenefits of the applied second degree of protection are:– all positive effects of the first degree are included plus the following benefits: