Environmental Science & Engineering - www.esemag.com - January 2005
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Idaho city chooses modular insulated cover system

By Brian Fraser

The City of Fruitland, in Idaho, recently completed a project to provide a new modular insulated floating cover system for their existing wastewater treatment facility. The City’s wastewater facility had average flows of 0.2 to 0.3 mgd (US). The facility has sufficient hydraulic capacity to effectively treat Fruitland’s domestic, commercial and industrial wastewater. The current design held the capacity for future domestic growth but concerns with algae, duckweed build-up and the high organic levels created little room for increased industrial loading without adequate pretreatment of high organic discharge levels.

Holladay Engineering Company in Payette, Idaho, was the consulting firm hired by the owner and was responsible for the design parameters for the treatment cell. This included reviewing various options for covering the treatment cell. The design criteria included providing a solution to mitigate algae growth, control odors and to provide an insulated environment for heat retention to enhance biological treatment rates.

The design of the cover system was particularly challenging as a result of the irregular shape of the anaerobic pond and the need to provide a custom-engineered, insulated floating cover system. Layfield Environmental Systems was awarded a contract to manufacture and install a custom- fabricated and installed modular insulated cover system. The design of the cover system included Layfield’s modular insulated covers (MIC) which are produced from highly efficient, closed cell insulation encapsulated between two layers of UV stabilized geomembrane sheet. The modular panels were mechanically joined using Layfield’s proprietary EC 102 and EC 101 hardware connection clips.

The cover system was fabricated at Layfield’s plant in Hollister, California, and took approximately three days to install. The cover system has proved to be highly successful in its application.

Municipalities across North America are increasingly using geosynthetic floating covers to help control algae growth, limit evaporation, retain heat and control temperatures. These important benefits help to reduce overall treatment costs and improve water quality.

Brian Fraser is with Layfield Environmental Systems Corporation in San Diego, California.
Contact e-mail: bfraser@layfieldgroup.com.

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