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The Role of Pharmer Engineering:
In 2005, the City of Fruitland’s water supply had elevated levels of nitrate and arsenic, with arsenic concentrations ranging from 20 to 39 micrograms per liter (µg/L). The City entered into a compliance agreement with the Idaho Department of Environmental Quality (IDEQ) in 2005 to address the new arsenic drinking water maximum contaminant level (MCL) of 10 µg/L mandated by the U.S. Environmental Protection Agency. Attempts at drilling new wells produced limited water, also with high levels of nitrate and arsenic.
In 2006, Pharmer Engineering was contracted by the City to address their water shortage and water quality issues. Pharmer Engineering was the lead engineering consultant and point of contact throughout the permitting, design, and construction phases of the project for regulatory agencies, public entities, consultants, contractors, and water users involved or affected by this project.
Pharmer Engineering prepared a facility plan describing the existing water system, identifying the points of concern in the water system, and outlining the long-term solution for the City. Pharmer Engineering’s solution consisted of using surface water instead of groundwater and upgrading the City’s water supply system. As part of the long-term solution implementation process, Pharmer Engineering worked closely with Federal and State regulatory agencies and multiple stakeholders directly or indirectly affected by this project to draft and submit the required permits and documentation prior to proceeding with the project design.
Pharmer Engineering was the lead design engineer for the entire project. Pharmer Engineering designed all treatment processes, including a river water infiltration gallery; a new surface water treatment plant that utilizes coagulation, membrane microfiltration, granular activated carbon (GAC) adsorption, chlorine disinfection, and pH control; a bolted steel storage tank with a booster station; and multiple water distribution improvements. Additionally, Pharmer Engineering supervised all civil, architectural, structural, mechanical, and electrical designs and coordinated the implementation of all designs into one document for regulatory review, contractor bidding, and construction.
Pharmer Engineering provided construction inspection services in all areas of the project. Such services included shop drawing review, biweekly progress meetings, addressing Request For Response (RFIs) from contractors, pay application review and recommendation, and construction supervision to guarantee that contractors complied with all plans and specifications set forth in the contract documents.
The Role of Other Consultants Participating in this Project:
Several consultants, specializing in hydrogeology; geology; archeology; architecture; and civil, geotechnical, structural, mechanical, and electrical engineering, were contracted by Pharmer Engineering to help successfully complete the project. These consultants were contracted to perform specific tasks within their areas of expertise and to help develop and implement a well‑supported, long-term solution for the City’s water shortage and water quality issues.
Pharmer Engineering’s Contribution to this Project in Each of the Rating Guidelines:
Original or Innovative Application of New or Existing Techniques
The Fruitland Water Treatment Plant includes a 3.2 million gallon per day Pall Membrane Microfiltration System configured in three racks of 78 membrane modules; each designed to treat the design flow with one rack out of service. Membrane technology is currently considered “cutting edge” technology for drinking water treatment. Pharmer Engineering developed a membrane procurement document specific to the Fruitland Water Treatment Plant to select a membrane manufacturer that could best meet the City’s needs. Pharmer Engineering conducted an extensive proposal review and recommended the contract be awarded to the Pall Corporation, one of the world’s largest suppliers of membrane filters.
This is the third drinking water plant in the state of Idaho that has installed Pall membranes. The plant designed by Pharmer Engineering provides a prime example of the implementation of this state‑of‑the‑art technology in southwestern Idaho.
In Fruitland, surface water quality decreases during the summer due to higher temperatures that enhance biological growth. This scenario requires additional filtration methods to remove organics, improve water taste, and eliminate unpleasant odors. Pharmer Engineering evaluated several options to implement additional filtration methods. The water filtration process designed by Pharmer Engineering combines membrane microfiltration technology with GAC for improved taste and odor control. Pharmer Engineering chose GAC for its high removal efficiency and low maintenance and operational requirements. The granular media is stored in six carbon steel pressurized vessels 10 feet in diameter and 20 feet high that are configured to operate with three trains in parallel; each train includes two vessels operating in series to increase removal efficiency. Similar to the membrane microfiltration system, the GAC system is designed to operate at design flow with one train out of service.
The treatment system also includes a chlorine disinfection system to inactivate harmful pathogens and a finished water pH control system to prevent corrosion in the distribution system. The disinfection system includes two 95,000 gallon chlorine contact basins designed to provide 85 minutes of contact time when both basins are operating.
Additionally, the system designed by Pharmer Engineering includes a membrane backwash recycle system intended to decrease the amount of water wasted during regular membrane maintenance operations. A membrane backwash is performed for every 24,000 gallons of water filtered per rack. Every membrane backwash requires 1,250 gallons of filtered water (5.2 percent of the forward flow), which equates to 166,000 gallons of water wasted daily for membrane maintenance at design flow conditions. The recycle system includes an equalization tank and a solids inclined plate clarifier that allows the owner to separate the solids from the backwash water and return 90 percent of the reject water to the head of the plant for treatment.
Future Value to the Engineering Profession
Pharmer Engineering conducted an extensive evaluation of the City’s water system and recommended a complete change in direction to guarantee a long-term solution for the City’s water shortage and water quality issues. Every case should be carefully evaluated, and although a complete redesign may not always be the answer, switching water sources and designing an entire new treatment system was the most cost-efficient, long-term solution for Fruitland.
The new Fruitland Water Treatment Plant is an example of the engineering approach being taken by multiple municipalities and industries on widely occurring issues related to water shortages and quality. As the maximum contaminant levels (MCLs) for regulated inorganic chemicals commonly found in groundwater become more stringent, communities across the state may contemplate switching to a surface water source treated with membrane technology. The Fruitland Water Treatment Plant will provide an example of an existing membrane technology system for other communities to examine the system and evaluate whether or not such technology would be applicable to their specific case.
Social, Economic and Sustainable Design Consideration
The new surface water treatment plant is a major upgrade for the City’s drinking water system and makes Fruitland an area leader in water treatment technology and a point of reference as these systems spread across the state due to the increasingly stringent MCLs mandated by State and federal agencies. The new water system could also potentially attract more industries due to the reliability and increased capacity of the upgraded infrastructure.
The new surface water treatment system guarantees the health, safety, and welfare of the public with minimal environmental impact. Membrane microfiltration is a proven technology in drinking water systems that provides quality water and, when combined with GAC filtration and chlorine disinfection, protects the end user from harmful pathogens and disinfection byproducts. The backwash recycle system represents an added environmental benefit to the water system by decreasing the amount of water wasted during daily membrane maintenance operations.
The Fruitland Water Treatment Plant presented a highly complex project with multiple components to consider and multiple issues to resolve. Water shortages, high arsenic concentration levels in groundwater, and an aging infrastructure contributed to the need to evaluate an alternative solution that would guarantee a safe, quality, long-term water supply.
The project included an added challenge: time constraint. The City of Fruitland entered into a compliance agreement with the IDEQ to meet the new Federal Drinking Water Standards mandated by the EPA by 2011. The magnitude and complexity of the project required time for evaluating, planning, permitting, designing, building, and commissioning the new water system. The project was broken into 10 packages, allowing construction of portions of the project to begin before design and permitting of the entire system was completed. This strategy allowed the first stages of construction to begin in February 2008 and the last piece of the design—the new membrane microfiltration surface water treatment plant—to be finished and bid in November 2008. Construction and commissioning were completed in September 2010, which allowed the City to be in compliance by their consent order deadline of January 2011.
Exceeding Client/Owner Needs
Pharmer Engineering exceeded the Owner’s expectations in this project by having a system designed, constructed, and operating before the federally mandated deadline and under budget. Pharmer Engineering kept the City involved during the entire process and regularly attended City Council meetings to keep City officials updated on the project. The implemented recommendation was the most cost-effective approach for the City in the long term and provided one central treatment system. With Pharmer Engineering’s ability to quickly address the City’s immediate water needs and prepare and implement a facility plan, the City was able to complete construction by September 2010, which allowed the City to be in compliance before the IDEQ’s January 2011 deadline. The budgeted cost for the entire project was $14.8 million, and the total final cost was $14.4 million. The totality of the project funds were managed by Pharmer Engineering.
Why is this Project Worthy of Special Recognition?
The Fruitland Water Treatment Plant presented unprecedented challenges for Pharmer Engineering and the City of Fruitland. The magnitude of the project required detailed engineering design and careful coordination by the lead engineer to deliver a successful project.
Figure 4: Aerial View of Payette River Intake and Water Treatment Facility
Meeting the new stringent water quality standards required a new approach: changing the City’s drinking water source from groundwater to surface water and upgrading the City’s drinking water system. Designing and installing an infiltration gallery in the Payette River bed required a complex engineering design and presented a construction challenge due to the nature of the project. The new surface water treatment plant combines state-of-the-art membrane microfiltration technology with systems to improve taste, reduce odors, and disinfect the drinking water to deliver a safe, quality product to the community. The treatment system is fully automated and requires low operator intervention and maintenance. The new bolted steel storage tank provides the City with additional fire flow capacity and the infrastructure necessary to meet increasing water demand as the City grows. These upgrades and improvements have made Fruitland a point of reference for other Cities in southwestern Idaho considering water upgrades.