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Philadelphia University Faculty of Engineering Department of Civil Engineering First Semester, 2013/2014. Environmental Engineering 441. Lecture 3: Water Treatment. Objectives of Water Treatment.
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Philadelphia University Faculty of Engineering Department of Civil Engineering First Semester, 2013/2014 Environmental Engineering 441 Lecture 3: Water Treatment
Objectives of Water Treatment “ To remove harmful microorganisms or chemicals, thereby preventing the spread of disease in order to supply clean and safe water for public demand”
Water Source Water source could be • River • Lakes • Groundwater; most likely better quality than surface water • Rainwater ++/ Dam • Raw water quality varies with the source, and if the source is surface water, the quality vary seasonally, particularly with flooding, upland and lowland, etc
Selection of Treatment Processes Selection of the set of Treatment Processes will be based on : • Sources of water intake • Characteristic of water Detailed raw water quality analysis for a minimum of one year, or longer, at periods of high, low and medium flows. The parameters to be looked at all those listed in the legislative standards • Cost • Suitability of the processes for removing particulate impurities. Example: • Turbidity; suitable process might be coagulation , sedimentation or filtration • For pathogen, pre or post chlorination, UV, ozone, or chloramines
Water Treatment Processes • Pretreatment of water • Screening • Storage, Equalization & Neutralization • Aeration • Chemical pretreatment • Sedimentation, coagulation and flocculation • Filtration • Slow Sand filtration • Rapid Gravity filters • Disinfestations • Chloramines • Ozone • UV radiation • Chlorination • Fluoridation • Advance Water Treatment • Iron & Manganese Removal • Water Softening by Chemical Precipitation • Ion Exchange • Adsorption • Chemical oxidation • Membrane Processes
Surface Water Treatment Typical treatment plant for surface water • Screening and grit removal • Primary sedimentation (settling/clarification) • Coagulation (Rapid mixing) • Flocculation • Secondary sedimentation • Filtration • Sludge processing • Disinfection
Groundwater Treatment Typical treatment plant for groundwater • Aeration • Flocculation/precipitation • Sedimentation • Recarbonation • Filtration • Disinfection • Solids processing