Pre-Filtering Multi Media Systems With Automatic, Self-Cleaning Filters

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•Case Study: Pre-Filtering Multi Media Systems With Automatic, Self-Cleaning Filters

Background:
Riviera Water District provides potable water for a small community at Clear Lake in Northern California. This lake historically produces significant summer algae blooms and, as a natural lake, has creek sediment runoffs in the winter.

As in many older water treatment plants, a multi media filtration system is used in the production of potable water. The media beds are composed of anthracite, sand and gravel and are the primary filter on the influent and raw water side of the Plant.

The Assessment:
The influent water is surface water which contains many organic types of debris. California canals and lakes can contain high levels of algae, water weeds, crustaceans and other floating debris especially in the summer months. In addition, winter storms and subsequent runoff can easily magnify total suspended solids (TSS) and nephelometric turbidity units (NTU) readings to very high levels.

As a result, these media systems would back flush often, producing a substantial amount of waste or back-flush water. This cleaning method also took the water treatment plant off line in its ability to produce potable water. Due to the high NTU & TSS levels, back-flushing the media filters could not be scheduled often enough to meet the community's water demand. In addition to automatic back flushing, manual "fire hose flushing" was necessary at 10-hour intervals when NTU levels and water demands were high. Additional overtime at the water treatment plant was needed to produce water, significantly increasing costs.

Click Here To Download:
•Case Study: Pre-Filtering Multi Media Systems With Automatic, Self-Cleaning Filters

SOURCE: Amiad Water Systems