SECTION 13223 FILTER DISINFECTION

SECTION 13223
FILTER DISINFECTION


PART 1 - GENERAL

1.1     SCOPE

A.   Provide labor, materials and equipment necessary to disinfect the filters prior to placing the filters in service.

1.2     RELATED WORK

A.   Section 13222 - Filter Underdrain System. B.   Section 13225 - Filter Washwater Troughs. C.   Section 13226 - Filter Media.
1.3     REFERENCES

A.   Kentucky State Board of Health; Water Treatment Plant Regulations.


PART 2 -  PRODUCTS

2.1     DISINFECTION SOLUTION

A.   Only products approved for the disinfection of water shall be used to disinfect each filter interior prior to placing it in service. The disinfection solution shall be made using either calcium or sodium hypochlorite and applied as specified.


PART 3 -  INSTALLATION

3.1     DISINFECTION PROCEDURE

A.   Extreme care is necessary in using chlorine.

B.   The interior of each filter shall be manually cleaned to remove any loose dirt or debris from the surface.

C.   The filter shall be backwashed. A chlorine solution of calcium or sodium hypochlorite shall be applied to the filter in order to provide a 50 parts per million (ppm) chlorine solution and be determined by a residual chlorine test on each filter.

D.   The 50 ppm chlorine solution shall travel through the filter by opening the filter effluent piping for a minimum of five (5) minutes. The filter effluent shall be closed and the water in the filter be brought back to the high water elevation. The chlorine residual shall be a minimum of 50 ppm at this point.

E.   The filter shall remain closed in the condition described in 3.01, D, for 24 hours. At the end of
24 hours, the chlorine residual shall not be less than 25 ppm. If the chlorine residual does decrease below 25 ppm, the disinfection shall be repeated. If the chlorine residual is over 25 ppm, the filter shall be thoroughly backwashed to remove all traces of the disinfection solution and then returned to service.