Elwood Waste Water Treatment Plant

This project was the construction of a new operational sewer treatment plant for the town of Elwood. Prior to construction the whole town was on septic tanks. After the completion of the project, ½ of the town was placed on a new sanitary sewer system.

At the treatment plant site three earthen storage ponds were constructed. The largest was the winter storage pond measuring 16.5 million gallons. The second largest was a 2 million gallon partial mix lagoon lined with HDPE with an aeration system. The smallest pond, the quiescent zone, measured 0.5 million gallons.

There were three large structures built on site. The first was a DBBR basin that involved a 23 foot deep excavation in sandy soil. This required us to over excavate the structure with slopes near 1:2 so as to keep the slope of the bank low for worker safety and to keep the work area from filling in. The Headwork’s Building, a CMU structure with wood trusses and metal roof, contained the blowers for the aeration system and two screw presses with a backup generator system. All electrical and SCADA are housed in the building. The last building, the Disinfection Building was a CMU structure with wood trusses and metal roof. It accommodated a chlorination system, a plant utility water supply system with a 4 hp pump, and two irrigation pumps that measured 15 hp each to provide the effluent water to local farmers.

The biggest challenge with the site was the excavation work. The entire site was sand, so bank stabilization was critical.Large scrapers were used on site to handle the majority of the material. Water was encountered for the excavation for the DBBR basin but was mitigated with setting a temporary well in one corner of the excavation and inserting a 2” pump to keep the area dry until backfilling occurred.