Transcript Lecture 7 (2014)

Philadelphia University
Faculty of Engineering
Department of Civil Engineering
First Semester, 2013/2014
ENVIRONMENTAL
ENGINEERING
343
Lecture 7:
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
WATER TREATMENT PROCESSES
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






Sedimentation, coagulation and flocculation
Filtration




Slow Sand filtration
Rapid Gravity filters
Disinfestations





Screening
Storage, Equalization & Neutralization
Aeration
Chemical pretreatment
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
1. Screening and grit removal
2. Primary sedimentation (settling/clarification)
3. Coagulation (Rapid mixing)
4. Flocculation
5. Secondary sedimentation
6. Filtration
7. Sludge processing
8. Disinfection
GROUNDWATER TREATMENT
Typical treatment plant for groundwater
1. Aeration
2. Flocculation/precipitation
3. Sedimentation
4. Recarbonation
5. Filtration
6. Disinfection
7. Solids processing