06-I Water Production Study - Laserfiche WebLink

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Backwashing practice involves the use of high velocity wazh water which is introduced into the filter bed in the direction opposite to the normal 5ltering flow. The backwash expands the 51ter beds 20 to 50 percent of the bed's original volume. The sole iue of backwash has not proven to be a satisfactory rystem for dual media filters which allow a deeper penetration of solids into the filter bed. 'Ihe deeper solids penetration requires a more efficient backwash rystem. In order to enhance the backwash capabilities with dual media, the Brown County Water Improvement Distric[ # 1 Treatrnent Plant has utilized both air and water backwash. This allows for a lower backwash water rate and provides for greater adaptation of the filter media t}uough the introduction of air. The air and water backwash system maintains the filter media in a cleaner condicion. 7) Mulriple disinfec[ion zone. The plant has three principal disinfection zones for flexibility of operation and oprimizarion of disinfeceon contact values throughout the plant. Disinfec[ion is currently accomplished by adding pre-chlorine in the water line between the temlinal storage reservoir and the rapid mi:t basin (Zone i). The free ctilorine is converted to chloromines in the rapid mix basin by the addition of amrnonia. and continues through filtraeon (Zone 2). Disinfection is cocrYpleted tkvough the transfer pump station and clearwell storage which is ba87ed prior to being delivered to the Disri-ict's first customer (Zone 3). By utilizing mulriple disinfecrion zones, disinfecrion by-products can be better controlled along with maintaining the proper disinfection residuals and contac[ times throughout the system. 8) Ba$led Cleazwells. The Disfict wu one of the first planu in Texas to add baffling in its clearwell storage to enhance and improve the disinfecrion contact rime. The c(eanvell contains five baffles varying in len;th from 40 feet to 60 feet in a circular tank. The baffles aze made of a vinyl curtain fabric material. The baffling arrangement provided increased the bafIling ratio in the cleazwell from 20°/a to approximately 80%. The District can reduce the required free chlorine addition by appro:cimately 50% and the required chloramine addirion by 20%. Water Treatment Desion Summarv Capacity 10. MGD Floccularion Two-stage, variable speed drive Sedimentarion Rectangulaz buin, 2 hr• Detention rime with tube settlers Filtrarion Variable declining rate filter control, dual media (Anthracite coal and sand) with air assisted backwash. Disinfecrion Pre-chlorination (Zone 1) ahead of plant, Chloromines (Zone 2) through plant and (Zone 3) in ba$led cleazwell . g, CpE IniHal Assessment needs It is becoming ever more difficult for water rystem operators to assess the planning for compliance with changing and evolving regudarions in the water industries. Operators of systems find it difiicult to dedicate the 6 me and resources necessary to stay current with