WATER TREATMENT AND PURIFICATION PROCESS: A CASE STUDY OF KIWASCO TREATMENT PLANT IN KISUMU,KENYA

METHODOLOGY .....................................................................................................................................................7
 OVERVIEW OF KIWASCO HISTORY AND  OPERATIONS .....................................…………………….....................8 

ORGANIZATIONAL STRUCTURE OF KIWASCO.......................................................................................................8
COMMERCIAL SERVICES DEPARTMENT.................................................................................................................9
FINANCE DEPARTMENT…………………………………………………………………………………...…........................9
HUMAN RESOURCES AND ADMINISTRATION DEPARTMENT...................................................................................9
INTERNAL RISK AND AUDIT DEPARTMENT.............................................................................................................10
 TECHNICAL SERVICES DEPARTMENT...................................................................................................................10
 SUPPLY CHAIN DEPARTMENT................................................................................................................................11
 OVERVIEW OF WATER TREATMENT PROCESSES..............................................................................................12     
         ( i) Intake…………………………………………………………..………………………….……...…........................12    
          (ii) Arrival at the Plant…………….………………………….….………………………………...….........................12          
        (iii) Sedimentation……………………………………………………………………………………............................12         
        (iv) Filtration ………………………………………….……………………………….................................................13      
         (v) Chlorination      .........................................................................................................................................13

CHAPTER 1 INTRODUCTION…………….................................................................................................................14

 CHAPTER 2 WATER TREATMENT………………………..........................................................................................14               
            2.1 SOURCES AND CHARACTERISTICS.....................................................................................................14             
            2.2 PRE-TREATMENT……………………………...........................................................................................15      
            2.2.1 pH ADJUSTMENT………......................................................................................................................15                
            2.2.2 WATER STABILIZATION………............................................................................................................16          
            2.2.3 COAGULATION & FLOCCULATION ....................................................................................................16                     

            2.2.3.1 JAR TEST…………………………………............................................................................................16
            2.2.3.2 COAGULATION…………………………………………………………….....................…………………...22         
            2.2.3.3 COAGULANTS ………………………………………………..................................................................25             
     
      2.2.3.4 FLASH MIXING/RAPID MIXING……...................................................................................................28       



            2.2.3.5 DETENTION
TIME….........................................................................................................................29  
           
2.2.3.6 TEMPERATURE
EFFECTS………………………………….................................................................30             



           2.2.3.7 ALUMINIUM RESIDUALS
...................................................................................................................31
 CHAPTER
3
SEDIMENTATION................................................................................................................................32
                  3.1
DEFINITION......................................................................................................................................32        



                  3.1.1 FACTORS AFFECTING
SEDIMENTATION.....................................................................................32          



                  3.2 SLUDGE
HANDLING.........................................................................................................................35
 CHAPTER
4
FILTRATION.....................................................................................................................
..................37
                  4.1 PURPOSE OF
FILTRATION..............................................................................................................37            



                  4.2 FILTRATION
PROCESS.....................................................................................................................37       



                  4.2.1 MECHANICAL
STRAINING...............................................................................................................37       



                  4.2.2
ELECTROLYTIC..............................................................................................................................38
                 
4.2.3 CHEMICAL
REACTIONS..................................................................................................................38               



                  4.3 TYPES OF
FILTERS...........................................................................................................................38         



                  4.3.1 THE SLOW SAND
FILTER................................................................................................................38
                  4.3.2 THE RAPID SAND
FILTER...............................................................................................................38              



                  4.3.3 DIRECT
FILTRATION.......................................................................................................................39
                 
4.4
BACKWASHING...................................................................................................................................39       



                  4.4.1 METHODS OF FILTER
BACKWASHING...........................................................................................41
 CHAPTER
5
CHLORINATION.....................................................................................................................................42 
              5.1 PURPOSE OF
CHLORINATION..............................................................................................................42     



              5.1.1 SOURCES OF
CHLORINE...................................................................................................................43
             
5.1.2 CALCULATING THE CHLORINE
DOSE….............................................................................................44        



              5.2 REACTIONS OF
CHLORINE...................................................................................................................44
             
5.2.1 OTHER USES OF
CHLORINE..............................................................................................................46