Frequent Alum pumps break down.

Loss of coagulation treatment (P, CH, M)

2

3

6

M

Li: it takes 3 months before it happens says operators, visual inspection reveals many broken alum pumps

C: untreated water supply

ECM: Treatment process is halted to restore the problem

E: Yes (but frequent breakdown need to be stopped)

2

2

4

M

Trident pipe clogged

Improper sedimentation (P, CH, M)

3

2

6

M

Li: sanitary inspection

C: leading to contamination

ECM: fishing road is used to flush it.

E: effective

1

2

2

Lo

Trident pipe breakage

Improper sedimentation (P, CH, M)

2

3

6

M

Li: sanitary inspection, discussion with plant operators

C: it reduces the rate of sedimentation leading to contamination

ECM: Replacement is done for any breakage

E: yes

2

1

2

Lo

Decantation pipe blockage

Inadequate sludge removal from sedimentation tank (P, CH, M)

1

2

3

Lo

Li: operators interview (blockage occurrence is very rare)

C: decantation pipe blockage only flushes sedimentation tank of flocculated material

ECM: No

1

2

3

Lo

Corrosion and algal blooms in sedimentation tanks

Contamination of treated water (CH, M)

3

3

9

H

Li: visual inspection, water quality results (increased in concentration of some water parameters).

C: contaminated water supply affects health

ECM: sedimentation tank is washed every 90 days

E: no; problems observed by field visits

3

3

9

H

Frequent Back washing Pump failures

Loss of backwashing, Clogging of filters which lead to reducing water quantity and quality (P, CH, M)

3

3

9

H

Li: discussion with plant operators reveals that

C: it affects both quality and quantity of water

ECM: problem is restored with immediate action

E: Yes but the frequent break down need to be curtailed

3

2

6

M

Filter beds exceeded life span

Improper filtration (P, CH, M)

3

3

H

Li: site visits and discussion with plant operators, water analysis results (increased in concentration of some water parameters).

C: improperly filtered water supply to the public

ECM: No

3

3

9

H

Corrosion and algal blooms in Filtration tanks

Contamination of water (CH, M)

3

2

6

M

Li: site visits and visual inspection.

C: contaminated supply

ECM: No

3

2

6

M

Leakages in backwashing machine through gasket

Reducing water quantity and corrosion (CH, M)

3

2

6

M

Li: visual inspection

C: loss of water supply, damage to facilities

ECM: No

3

2

6

M

Head loss to know when to back wash.

Loss of signal by operators the time required to back wash filter

3

2

6

M

Li: visual inspection during site visit

C: irregular backwashing time.

ECM: No

3

2

6

M

Chlorine dosing pump break down

Loss of disinfection (M)

3

3

9

H

Li: visual inspection

C: supplying water without disinfecting affects public health.

ECM: Manual chlorination

E: No (chlorine over dosing/under dosing indicated by consumers survey affecting aesthetics)

3

2

6

M

Post-liming pump break down

High acidity of treated water, corrosion (CH)

3

2

6

M

Li: visual inspection

C: aesthetics, damage to facilities

ECM: No

3

2

6

M