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close this bookSurface Water Treatment by Roughing Filters - A Design, Construction and Operation Manual (SANDEC - SKAT, 1996, 180 p.)
close this folderAnnexes
View the documentSimple methods for water quality analysis
View the documentSimple methods for discharge measurements
View the documentSalient data and features of slow sand filters
View the documentRoughing filter theory
View the documentPilot plant design examples
View the documentRoughing filter design examples
View the documentOutline for caretaker training
View the documentMonitoring of filter operation
View the documentAcknowledgements and credits

Monitoring of filter operation

1. Aim and Procedure

The aim of a monitoring programme is to:

- assess treatment plant performance
- establish guidelines for treatment plant operation
- improve treatment plant operation and efficiency

The caretaker carries out the field test and monitors, with the help of a logbook, operation and performance of the treatment plant. The supervisor, attached to the operation and maintenance section of the responsible institution, controls the monitoring programme of the caretaker by means of regular visits, takes water samples to be analysed in the laboratory, and summarises the monitoring results in annual reports.

2. Field Records

The monitoring programme has to cover the quantitative and the qualitative aspects. Discharge measurements characterise the operational conditions of the treatment plant and provide the quantitative information. Water quality tests allow qualitative assessment of the treatment process. Treatment plant operation requires flow control and adjustments on a daily basis. The water quality tests should also be carried out regularly; i.e., weekly. The equipment necessary for discharge measurements and water quality tests must therefore always be available at every treatment plant.

A field monitoring programme proposal is summarised in Table 8/1.

3. Bacteriological and Chemical Water Analyses

Bacteriological and chemical water analyses require more costly equipment generally not available at every treatment plant. The tests should also be performed by experienced staff. It is therefore recommended for the supervisor to perform such tests either at the site with field test equipment brought from the laboratory, or to take samples which will be analysed in the laboratory. Since field testing excludes the risk of delay and mishandling of the water samples, it should therefore be applied whenever possible, provided the equipment is properly maintained and checked prior to each field visit.

A bacteriological and chemical monitoring programme proposal is summarised in Table 8/2.

4. Field Visits

The supervisor will personally conduct on-site training of the caretaker, and will also be present during the initial stars of treatment plant operation. He will later assist the caretaker in his daily activities and supervise operation, maintenance and monitoring of the plant. Frequency of his visits is dependent, among other criteria, on the ability of the caretaker to operate his water supply system. However, field visits will at first be carried out weekly, then monthly and later every two to three months.

Such a post-project assistance is essential to ensure proper use of the installations, to identify possible problems at an early stage, and to compile practical experience gained for future projects.

5. Evaluation

The supervisors will compile the results of the monitoring programme in annual reports which will also contain the data sheets of the field test records and possible laboratory analyses. They will also comprise a short description of the operational experience (plant performance, encountered practical problems, exceptional events) and planned activities (operational modifications of the plant, major maintenance work, etc.).

Table 8/1 Field Monitoring




flow rate


every 2 days

filter resistance


1 x / week

filter resistance


every 2 days

of raw water


and RF + SSF effluents (at

2 x / week


high turbidity, filtrate of

(daily at periods of high

each RF gravel pack)


settleable solids

raw water

1 x / week

Table 8/2 Bacteriological and Chemical Monitoring Programme




E.coli or total coliforms or
Fec. Strept.

raw water and RF + SSF

monthly for the first half
year, later occasionally



total hardness


raw water

every 2 months



susp. solids cone.

Conversion Table


1 m


3.2808 ft

1 ft


0.3048 m

1 mm


0.0394 in.

1 in.


25.4 mm


1 m²


10.7639 ft2

1 ft2


0.0929 m²

1 cm²


0.1550 in.2

1 in.2


6.452 cm²


1 m³


35.31 ft3

1 ft3


0.0283 m³

1 litre


0.2642 gal

1 gal


3.785 litre


1 m/h


3.2808 ft/h

1 ft/h


0.3048 m/h

1 m/s


3.2808 ft/s

1 ft/s


0.3048 m/s

flow rate

1 m³/h


35.31 ft3/h

1 ft3/h


0.0283 m³/h

1 m³/s


35.31 ft3/s

1 ft3/s


0.0283 m³/s

1 m³/h


264.2 gal/h

1 gal/in


3.785 litre/h

1 m³/s


264.2 gal/s

1 gal/s


3.785 litre/s

filtration rate



0.4092 gpm/ft2

1 gpm/ft2


2.444 m/h




(1°F - 32)x5/9



9/5°C + 32