Operation and maintenance of a treatment plant is task. This is done to expand the life time of the treatment plant. So its necessary to keep the water treatment plant with a good look after on the hand of operation and also in maintenance both simultaneously. The given slides show some operation and maintenance processes to carry out a water treatment plant.

1. 1
K.A.J.W Siriwardhana.

2. Introduction.
“Operation and maintenance refers to all of the
activities needed to run a water supply and
sanitation scheme, except for the construction
of new facilities. The overall aim of operation
and maintenance is to ensure efficiency,
effectiveness and sustainability of water supply
and sanitation facilities”
-(CASTRO 2009)
• Operation & Maintenance (O&M) service
means that we care about your assets.
2

3. With our experienced and highly qualified
personnel we will provide the following services:
• Operation (24/7)
• Preventive Maintenance
• Corrective Maintenance
• Condition Monitoring
• Remote Monitoring by Expert Center
• Provision of Spare Parts and Consumables
• Repair and Refurbishment of major
components
• Execution of scheduled Outages
3

4. Operation and maintenance of a water treatment plant.
4
Screeners:
• In the case of hand raked screens, the screens should be raked at least hourly.
• Screenings should be allowed to drain for an hour, until the screen is raked
again.
• Surfaces on which screenings have been deposited, should be hosed down on a
daily basis, in such a way that wash water flows back into the wastewater
stream.
• There is often more than one grit channel or grit removal hopper.
• Grit channels should be taken out of operation at least once a day, drained and
the grit deposited onto drainage platforms
• The total flow should be read daily at the same time and recorded.

5. Screeners(cont.):
5

6. Coagulation & flocculation:
• There usually are two parallel systems of coagulation/flocculation units in a
treatment plant to facilitate removing one half of the basins from service for
maintenance.
The best flocculation usually is achieved by more than one unit in a series.
Each unit is separated by baffles to prevent short circuiting.
Also, all inlets and outlets are baffled to prevent short circuiting.
• The flocculators usually are driven by variable speed drive units. With multiple
units, it is desirable to reduce the speed of the flocculators in each succeeding
unit to prevent breaking up the large floc particles which have formed.
• The flocculators should have a detention time of 30 minutes.
6

7. • In the event the flocculation units appear to be ineffective, a careful
analysis of the process should be done using jar tests, varying both the
doses of chemicals and the speed of the flocculators to determine if an
improved process could be developed.
• The maintenance of the flocculation drive units usually is lubrication of
the motor and drive units according to the manufacturer's
recommendations.
• Horizontal paddles usually have submerged bearings, drive chains, or
packing which requires additional checking and maintenance.
• The flocculation basins should be drained approximately every six months
to check the condition of the paddles or blades, to remove any
accumulation of settled material, and to check on the condition of the
basin's structure.
7
Coagulation & flocculation (cont.):

8. • Sedimentation is the slow, quiet settling of the floc and suspended
matter from the water by gravity. The sedimentation basins can be
rectangular or circular in shape.
• There should be at least duplicate units to facilitate cleaning.
• The basins should have a detention time of four (4) hours.
• The inlet devices should be designed to distribute the water for
uniform velocities and care should be taken to prevent short circuiting
of flows.
• There should be surface skimming to collect floating debris, such as
leaves, scum, etc.
• When the basins are drained for cleaning, the condition of the basins
and the sludge collection equipment should be checked carefully.
8
Sedimentation:

9. Sedimentation(Cont.):
9

10. Filtration:
• The filtration process is the passing of the water through a bed of fine material, such
as sand, coal, or other fine granular material. The filter media can be uniform in
sizing, but higher and more effective filter rates are attained by use of mixed media.
• As a coating builds and penetrates into the filter bed, the head loss across the filter
becomes greater until the flow rate is greatly reduced. At this time the filter must be
backwashed to cleanse the media of the floc and particulate matter.
 The filter control valves should be checked routinely for proper operation and
any leakage.
The filter media should be examined annually to evaluate its overall condition. Is
the media uniformly graded and distributed? Is there the proper depth of each
gradation of media? Expose the underdrain system to check if the holes or
nozzles are clogged.
 The backwash and surface wash pumps should be checked and lubricated
according to the manufacturer's recommendations.
 The surface wash equipment, including nozzles, should be checked periodically
for free operation and proper position over the media. 10

11. Disinfection:
• Water can be disinfected by heat, radiation, or chemical treatment; however,
the only widely accepted method is chemical treatment.
• Chlorination usually is accomplished by either gas chlorinators, hypo-
chlorinators or chlorine dioxide generators.
On a daily basis chlorinators should be inspected for proper operation
and leaks. The items to be checked should include injector water
supply pressure, injector vacuum, chlorine supply pressure feed rate
on roto-meter tube.
The chlorine residual should be checked and recorded.
On a weekly basis check chlorinator feed rates through the full range
of its capacity, clean any filters, and check operation of all valves.
On a monthly basis, exercise all chlorine valves, inspect ventilation,
heating, and lighting equipment for proper operation.
Check the chlorinator vent line for obstructions such as insect nests,
inspect the vacuum system for leaks, and perform other
maintenance.
Inspect all safety equipment for proper operation including chlorine
alarm system and the self-contained breathing apparatus or gas
masks. 1
1

12. Disinfection(Cont.) :
12

13. Disinfection(Cont.) :
• Some abnormal operating conditions which could occur are:
Chlorine leak - A chlorine leak is usually detectable by your sense of smell as
soon as you arrive at the chlorination location.
Low gas pressure - If the chlorine gas pressure drops, it usually is the result
of the chlorine container being empty, clogged filters, or closed valves. To
correct, replace the container, clean the filters, and check the valves.
Injector vacuum too low - If the injector vacuum drops too low, the
chlorinator should automatically shut off. The cause of the vacuum being
low is a leak in the vacuum hoses, low water pressure, or clogged ejector.
If there is a vacuum leak, repair the leak. If there is low water pressure,
check the source, pump operation, or line strainers. If the ejector is
clogged, remove and clean it.
13

14. Disinfection(Cont.) :
14

15. Advantages. Disadvantages.
•O&M activities ensure that the project
is sustainable in a long-term
•O&M allow for the correct provision of
services and benefit of end-users
•O&M prevent the systems to collapse
creating environmental and health
hazards
•Community can be involved in O&M
• O&M activities cost time and money,
and therefore a provision for financing
O&M has to be planned before the
project starts
15

16. Reference
1. Beyond, A., Control, E. S., & Knowledge, O. (n.d.). Chapter 3 O & M
Management, 1–15.
2. Plan, M., & East, F. T. (2000). APPENDIX B OPERATIONS & MAINTENANCE PLAN.
3. Requirements, B. (n.d.). OPERATION AND MAINTENANCE MANUAL FOR WASTE
WATER TREATMENT WORKS DPW ’ s BASIC REQUIREMENTS.
4. Swartz, C., & Utilisation, W. (n.d.). OPERATION OF WASTEWATER TREATMENT
PLANTS.
16

17. THANK YOU
17

18. 1. Why do we need to operate and maintain a water treatment plan?
2. What are two main maintenance methods?
3. What should be checked in the water treatment plant in daily routines?
4. How do the durability of assets are ensured with maintenance purposes?
18