§ 34-579. Diatomaceous earth filters.

(a)

Filter tank and septa. The filter area shall be determined on the basis of effective filtering surfaces, with no allowance given for areas of impaired filtration, such as broad supports, folds or portions which may bridge the filter elements. The bottom of open vacuum filter tanks shall slope to a drain to facilitate complete drainage of the tanks.

(b)

Appurtenances. Pressure filters shall be equipped with an air-relief valve, influent and effluent pressure gauges with a minimum face size of two inches, and an in-line sight glass, on the backwash line. A vacuum gauge with a minimum face size of two inches shall be provided on the pump suction line for vacuum filter systems. All appurtenances shall be conspicuously located for quick inspection.

(c)

Piping and valves. The filtering system shall be designed with all valves and piping that allows filtering to pool, pre-coat recirculation and/or pre-coat to waste, complete drainage of the system, bypass filter to waste, and backwashing to waste. The piping layout shall accommodate proper maintenance, operation and inspection. If pre-coat recirculation is used in a pressure system, an in-line sight glass, minimum two inches in length and a valve shall be provided in the pre-coat piping.

(Ord. No. 09-0120, 1-7-09)