FOX Receives Engineering Excellence Award

FOX Engineering Associates, Inc. and the city of Hills are recipients of the 2017 American Council of Engineering Companies (ACEC) Honor Award for Engineering Excellence in the Water and Wastewater Category for the Hills, Iowa, Municipal Water System.

The city of Hills, with a population of approximately 700 people, did not have a community water system. Most residents obtained their water from private, individual wells in a shallow sand and gravel aquifer. Many shallow wells in and around the city were found to be contaminated with nitrate above the MCL. Many of these shallow wells had also tested positive for bacteriological contamination.  In addition, a number of these wells were found to be contaminated with perchlorate.  Although perchlorate was an unregulated contaminant, EPA had recently issued a final regulatory determination, a formal decision to establish a national primary drinking water regulation for perchlorate.

Facing the need to address these problems and other water supply deficiencies in the community, such as lack of water for fire protection, the City retained FOX Engineering in 2004 to prepare a Preliminary Engineering Report to investigate the possibility of establishing a public water supply system to furnish a safe and reliable water supply to its citizens. The 2004 report evaluated several different options for water supply and treatment, and recommended creation of a public water system. The creation of a public water supply required a vote from the citizens, which originally did not pass.

Careful planning was required throughout the construction process. Each month this figure was updated to show the progress on the water distribution system and service connections.

In 2011, with growing concerns about perchlorate and other contamination of the shallow aquifer, FOX Engineering was retained to update the 2004 PER to consider cost increases and other available information.

The Preliminary Engineering Report looked at several options for addressing the water quality concerns in Hills. These included several different water supply options (alluvial aquifer, glaciofluvial aquifer, bedrock aquifers, surface waters, and purchased water), and several treatment options (disinfection, iron & manganese removal, fluoridation, chemical addition, softening, and reverse osmosis).

The report also looked at individual wells and treatment, and “cluster” wells and treatment to serve multiple homes. The report considered several options for sizing the distribution system, including offering fire protection and without fire protection. Storage options evaluated included ground storage vs. elevated storage and pumping. Another option included purchasing finished water from Iowa City, which would involve construction of a 4.5-mile water main. The selected alternative was based on the lowest cost and most beneficial option for the city, which included building a public water system.

The selected alternative included the city acquiring two existing wells within the city. Both wells were in the same deep glaciofluvial aquifer; one served a relatively new sub-division within the city limits, and the other well served an industry in town. Water quality testing of the wells found relatively high concentrations of ammonia in the raw water, around 3 mg/L. Several options were considered for ammonia removal, including breakpoint chlorination, sodium chlorite addition, biological filters, ion exchange, and reverse osmosis. Due to the added benefits of reverse osmosis, including softening and removal of other contaminants, the city chose reverse osmosis treatment.

Prior to designing and constructing an RO system, IDNR requires that an on-site pilot study be completed. FOX assisted the city in evaluating, selecting, and procuring the RO pilot unit for the study.

The reverse osmosis pilot unit was installed in an existing well house owned by a residential development. The pilot unit operated for about 4 months, testing the operational and design parameters for the RO system.

The reverse osmosis pilot unit was installed in an existing well house owned by a residential development. The pilot unit operated for about 4 months, testing the operational and design parameters for the RO system.

FOX Engineering assisted in evaluating pilot system proposals from several manufacturers; once selected, a Pilot Protocol was developed that outlined goals and objectives for the study, described equipment to be tested, how the equipment will be installed and operated, parameters to be sampled and the frequency of sampling, startup and shutdown procedures, and reporting requirements.

Since day-to-day operation of the pilot unit was performed by city staff, FOX worked closely with them to develop protocols and coordinated submittal to and approval of the plans by DNR. Upon completion of the pilot study, operational data and water quality analysis were reviewed and recommendations for design of the full-scale system were developed. The results of the pilot study were summarized in a pilot study report which was submitted to the Iowa DNR for review and approval before design of the full-scale pilot systems began. The pilot study was conducted from April – July 2013.

During design, two rather innovative and unique aspects were incorporated into the water plant to save money, improve efficiency, and simplify construction. To provide redundancy for the RO system, at least two RO systems had to be provided. This is typically provided with two separate RO skids, each capable of operating independently of the other. To save money and space in the overall plant design, an innovative approach was used by combining two RO systems on one skid. This greatly reduced the footprint of the RO system, while still providing the same level of redundancy and reliability. The other innovative aspect incorporated into the design was the use of unique concrete form masonry units, OneStep Building System, for the building construction. This system simplified construction, while provide an aesthetically pleasing, strong, and energy efficient structure.

The new water plant was designed and constructed using a unique insulated concrete form masonry unit, OneStep Building System, which simplified the building process and provided a strong, energy efficient structure.

The new water plant was designed and constructed using a unique insulated concrete form masonry unit, OneStep Building System, which simplified the building process and provided a strong, energy efficient structure.

The RO system provides removal of ammonia, hardness, and other contaminants to provide a high quality finished water. Two RO systems were provided for redundancy, but to reduce the cost and footprint, both systems were installed on one skid.

The RO system provides removal of ammonia, hardness, and other contaminants to provide a high quality finished water. Two RO systems were provided for redundancy, but to reduce the cost and footprint, both systems were installed on one skid.

After chemical addition, the blended permeate and bypass water enters the clearwell tank before being pumped to the water tower.

After chemical addition, the blended permeate and bypass water enters the clearwell tank before being pumped to the water tower.

The city also elected to provide fire protection to the community. This included construction of an all new water distribution system, consisting of mostly 6” and 8” water mains with fire hydrants and valves. A new 200,000-gallon water tower was included in the project to provide adequate storage and fire protection for the city.

To fund the project, FOX assisted the city in applying for an SRF loan. In 2012 the city was awarded an SRF loan with 50% of the loan forgivable. That same year, the community voted in favor of creating a public water system.

The water plant was in operation by July 2015, and the project was substantially complete in November 2015. The total project cost was approximately $5.77 million.

ACEC award applicants were judged on five criteria: original or innovative application of new or existing techniques; future value to the engineering profession and perception by the public; social, economic, and sustainable design considerations; complexity; and exceeding client/owner needs. FOX Engineering’s design provided convincing evidence to the ACEC judging panel that each of these criteria were met.

 

FOX Engineering is an environmental engineering firm based in Ames, Iowa. We specialize in water and wastewater solutions for our diverse municipal and industrial clients. Our work varies in size and scope and can be found throughout the Midwest and beyond.