Section 930.30  Treatment Plant Operation

a)         Slow sand filtration plants shall comply with the following.

1)         Disinfection of Storage Tank.  The walls and bottom of the storage tank must be free of dirt and debris prior to operation.  The side and bottom must then be washed with a chlorine solution of 100 parts per million.

2)         Prior to operation, the filter must be disinfected with a solution of 100 parts per million.  The effluent valve is to be closed, and this solution must remain in the filter for at least 24 hours.

3)         Before water is allowed to flow to the filter, a clean piece of wood, fiberglass or a metal plate 2 feet square must be placed on the surface of the sand in order to prevent the initial water from disturbing the sand.  After the filter has reached operating level, the plate must be removed.

4)         Filtration Rate.  The filtration rate shall not exceed 2 gallons per minute for each 25 square feet of sand filter area.

b)         Cartridge filtration treatment plants shall comply with the following.

1)         The flow rate shall not exceed the maximum design flow rate for any of the filters or disinfection system.

2)         The water pressure shall be maintained at 20 pounds per square inch or greater downstream of the treatment plant.

c)         Disinfection shall comply with the following.

1)         If chlorine disinfection is used, a minimum free chlorine residual of at least 0.2 mg/L shall be maintained at distant points in the water distribution system and a minimum free chlorine residual of 0.4 mg/L shall be maintained in the water storage tank.

2)         If ultraviolet disinfection is used, the ultraviolet disinfection equipment shall be kept in continuous operation 24 hours per day.

(Source:  Amended at 27 Ill. Reg. 15998, effective October 1, 2003)