Municipal / Environmental

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Bellevue Wastewater Treatment Facility

IIW integrated new technology into wastewater treatment plant to give the City of Bellevue a more simple and clean process. The facility replaced a single path trickling filter plant that was hydraulically and organically overloaded with a new extended aeration activated sludge (AeroMod) system. The IIW engineering team developed a plan to address excessive inflow […]

Continuous Discharge Lagoon

The City of Mechanicsville faced a problem: The amount of inflow and infiltration (I&I) into the sanitary sewer reduced the overall wastewater detention within the existing aerated lagoon system. They needed a solution and called on IIW’s environmental engineering team to find it. IIW’s environmental engineers began with conducting a cost benefit analysis. The findings […]

Lagoon Upgrade and Headworks Improvement

In order to deal with extreme I/I flows, the City of Wyoming’s wastewater treatment facility (WWTF) is transitioning from a controlled discharge lagoon to a continuous discharge process. Their lagoon size could only handle a certain level of flow due to high I/I flows—the WWTF was discharging multiple times per year which was in violation […]

Lansing Wastewater Pumping & Treatment Facility

Using the technical expertise of IIW’s engineering team, the City of Lansing upgraded its wastewater treatment system with a newly constructed extended aeration treatment plant (AeroMod) that’s also accompanied by a new administrative and laboratory building on site. The new facility, located adjacent to the Mississippi River, replaced an aging contact stabilization plant. The environmental […]

Leisure Lake Wastewater Treatment Facility

With an conservative eye, the IIW environmental engineering team completed an overhaul of Leisure Lake’s Wastewater Treatment Facility that reduced project costs and delivered long-time energy savings. IIW’s engineers replaced more than 400 on-site septic systems with a three-cell controlled discharge lagoon with a synthetic liner. Rugged topography and excessive costs of conventional sanitary sewer […]

Miles Wastewater Treatment Facility

The WWTF in the City of Miles was originally constructed in 1968. It is nearing the end of its mechanical life and does not meet current standards for redundancy. In addition, during facility planning, the 100-year flood elevation was determined to be significantly higher than the existing structures, which would have required flood protection measures. […]

Peosta Wastewater Collection System Improvements

IIW recently completed a Facility Plan for a new wastewater treatment facility (WWTF) in the City of Peosta. The City of Peosta has been experiencing rapid growth since 2005 and their existing lagoons are currently loaded to more than 70 percent of their rated capacity. Previous planning studies indicate that capacity may be reached within […]

Peosta Wastewater Collection System Improvements

The City of Peosta has experienced both tremendous population growth and commercial development in the past twenty years. To meet future demand, the City is expanding its sewer capacity in two areas of the City in anticipation of further growth. IIW is designing nearly 9000 LF of sanitary sewer piping. The project consists of two […]

Preston Wastewater Treatment Lagoon

The City of Preston hired IIW’s team of municipal engineers to design a replacement aeration system for the existing wastewater treatment lagoon. The new aeration system was installed in the first two cells of the five-celled lagoon. In addition to the aeration system, a recirculation pumping system was constructed to allow for effluent from the […]

Sludge Management

Soon after the City of DeWitt, Iowa, called on IIW to propose a plan for sludge management at the existing wastewater facility, city leaders learned of a new industry development that would bring the plant to 98 percent capacity. IIW’s engineers remained nimble and responsive to the City’s needs as they worked to set new […]

WWTF Lagoon Upgrade, Headworks Improvement

The City of Fayette’s wastewater treatment facility (WWTF) did not meet current DNR ammonia limits for wastewater effluent. With IIW’s design expertise, the City of Fayette was able to meet the DNR limits with a 2015 lagoon upgrade and headworks improvement. The Headworks Building Improvements included replacing equipment for flow measurement, fine screening, grit removal, […]

Wastewater Treatment Facility, Calamus

IIW completed a facility planning study for the City of Calamus’s WWTF. The study identified an expansion of the existing two-cell controlled discharge lagoon system to a three-cell controlled discharge lagoon system. This would bring the WWTF well under the limits of the DNR. The improvement project includes construction of a primary cell lagoon at […]

Wastewater Treatment Facility, Phases I, II, and III

IIW has a long history of providing engineering services to the City of Dyersville. The original mechanical WWTF at the current site was constructed in 2001-2002. This project, now referred to as Phase I improvements, primarily included an influent lift station, a headworks/administration building with mechanical fine screening and grit removal, a three-channel oxidation ditch, […]