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Wastewater Division

Wastewater Plant Update

Posted: August 5, 2008

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

SEEPS One of the project’s last structures to be excavated and constructed is the Secondary Effluent Equalization Pump Station (SEEPS). The excavation for this structure will be deep, as the Influent Pump Station (IPS) was, and will encounter ground water, too.

But, like the IPS, fabric and gravel is laid atthe bottom of the excavation to stabilize the soil for the rest of the structure. This pump station will take the plant flow that is equalized in the will-be modified existing aeration tanks and pump it downstream to filtration and disinfection.

IPS Since the foundation slab and first wall pours were completed in June, forming and pouring the remaining height of the walls was completed in July. Backfilling around the pump station structure was begun.

Grit treatment Much of the concrete work has been completed, so the equipment has started to move in. Blowers and pumps are located next to the aerated grit tanks and the grit washing and dewatering equipment was located on its concrete pad waiting to be plumbed in and powered up.

Oxidation Ditches (OD) Much of the equipment such as the propeller mixers and the dissolved oxygen measuring instruments were installed. Additionally, installation started on the air lines which will deliver air from blowers to diffuse into the wastewater being treated. The microorganisms who live in the ODs, need oxygen to live and remove the pollution from the wastewater. The blowers will be located in a structure next to the new electrical building. The metal framework for this blower building was erected.

Secondary Clarifiers More of the internal workings of these sedimentation tanks were installed including scum collector beaches and bottom sludge collectors . These clarifiers slow the water down and let the lighter material (scum) float and the heavier material (sludge) sink; then these materials are collected and removed for additional treatment.
Electrical Since the 2 new transformers were installed last month, the electrical contractor has started pulling cable from the transformers to the switchgear and from the switchgear to the individual pieces of equipment. They will also be testing the soundness of the wiring by checking the continuity of the circuits. Construction management inspectors will document this testing.

Solids Handling In addition to all the work on the liquid side of things, the structure for the new boiler building was also installed. The anaerobic digesters, which breakdown the solids in the treatment process, need to operator at human body temperature. These new hot water boilers will burn the gas produced by the digesters (methane) to make hot water; the heat from the water is transferred to the digesters to keep the microorganisms in their comfort zone. Solids from the digesters are held in lagoons. One of the lagoons has already been rehabilitated and is now in service; the second lagoon is being contoured and made ready to receive its plastic liner.

Check back again in September to see what happened in August.