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Wastewater Division

Wastewater Plant Update

Posted: June 10, 2008

Update May 2008: (Click on thumbnails to view pictures larger)

Influent Pump Station. After the over-excavation and soil stabilization was completed, rebar and forms were started for the foundation slab and station walls

The slab was poured and the pours for the walls are on going. Influent piping was fabricated and installed. The discharge piping was wrapped and laid in its trench. This piping will carry the pumped wastewater to the grit treatment unit.

Grit Treatment. Large (blue) isolation valves were installed on the discharge piping from this treatment unit. Between these valves will be installed automatic flow control valves which will regulate the volume of water entering the downstream Oxidation Ditches.

Ditches. The yard piping for the influent flow to the ditches was wrapped and installed to meet up with the concrete inlet structure. This structure had installed the three influent sluice gates which will direct the flowing wastewater to the in-service ditch(es).

The concrete pours of the walkways over the ditches were completed, so the support scaffolding was stripped and removed from the tanks. New air blowers will be required for the ditches and work continued on the foundation work for that new building.

Secondary Clarifiers. Fabrication of the effluent launderers was completed and they were installed in all three of the tanks and the center columns and additional structures began going in

Flow Equalization (EQ). After the water leaves the secondary tanks, it’ll be piped to a new EQ basin which will balance the flow into the downstream treatment units. Work began on the excavation for the EQ pump station by first installing soil stabilizing sheet piles . Sheets piles have been used throughout the project site. A portion of these sheets will remain in place after the excavation is backfilled to support adjacent structures.

Metals Removal. There is no metals removal! The City was able to have our regulator modify the plant’s discharge limit for molybdenum so the designed and partially built metals removal treatment unit will not need to be completed. Apart from saving construction costs, the City will save also the annual expense for operating the treatment unit (mostly chemical costs). The quality of the effluent discharged without this treatment will not degrade the quality of the receiving water.

Filtration/UV (FUV). The exterior of the FUV building was being completed and work continued on the interior of the building . Since the tertiary filters had been installed, work began to install the appurtenances such as the backwash pumps and piping.

Lagoons. Contouring of the west lagoon was completed and installation of the heavy duty liner started . The entire floor and sides of the lagoons will be lined. The liner is secured along its perimeter by a deep ribbon of concrete.

Electric. Throughout the site, the contractor was busy installing more trench ducts in which the power and control cables will be laid. In the new electrical building, many of the new control panels were installed.

The final work on the building roof was also completed . Preparation of the location for the new emergency engine-generator also continued

Check back again in July to see what happened in June.