CCP 11-28-2006 - Laserfiche WebLink

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. . . New Brighton, MN November 8, 2006 Page 2 by radium attaching to the manganous oxide. Therefore, the City is moving forward with replacing the existing filter media and rehabilitating the water treatment plant. Project Description In general, the project consists of sandblasting and painting the entire filter interior, installation of an airwash system for the backwash process, mid installation of new media as directed by the City at a 10-17-06 meeting. More detailed descriptions are listed below. The City currently has a contract with KLM Engineering Inc. to inspect and provide a recommendationconceming the condition ofthe existing paint coatingand welds in WTP No.4. As we have not yet received a copy ofthe report by KLM Engineering Inc. of the filter condition and recommendations, the scope ofthis rehabilitation project is not completely defined. Sandblast and Paint Filters & Piping The entire filter interior is to be sandblasted, primed, and re-coated. If requested by the City, the filter exterior and piping can be re-coated in addition. New Filter Media New support gravels will be added to separate the filter media from the backwash nozzles. The filter media will be a layer of manganese greensand followed by anthracite coal. Airwash System An airwash system will be added for improved backwashing. This includes an airwash header and lateral system, 5 pneumatic valves, and welded openings in the existing filter. If possible, the City intends to salvage a blower to provide air. Welding Any existing welds which are in poor condition will need to be re-welded. KLM Engineering Inc. will provide a summary of the existing welds and recommendation for returning the filter to optimal condition. SCADNControl Work The controls sequence will be adjusted to include airwash followed by water backwash. A level probe will be added to each filter cell to optimize the backwash sequence. Underdrain System If the welds on the existing underdrain system are in poor condition, it may be necessary to replace the existing underdrain system with a header-lateral system cast in a concrete base. Following the completion ofthe inspection by KLM Engineering Inc., a decision concerning the existing underdrain system can be made, Evaluation of the HMO chemical.feed system installed by the City The City has installed a HMO chemical feed system which we will evaluate as a part of this project. We do not anticipate making any changes to the existing chemical feed system.