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1 <br /> fi Cerra® <br /> Basic Operations <br /> Filterra®is a bioretention system in a concrete box. Contaminated stormwater runoff enters the <br /> filter box through the curb inlet spreading over the 3-inch layer of mulch on the surface of the <br /> filter media. As the water passes through the mulch layer, most of the larger sediment particles <br /> ' and heavy metals are removed through sedimentation and chemical reactions with the organic <br /> material in the mulch. Water passes through the soil media where the finer particles are removed <br /> and other chemical reactions take place to immobilize and capture pollutants in the soil media. <br /> ' The cleansed water passes into an underdrain and flows to a pipe system or other appropriate <br /> discharge point. Once the pollutants are in the soil, the bacteria immediately begin to break <br /> down and metabolize the materials and the plants begin to uptake and metabolize the pollutants. <br /> ' Some pollutants such as heavy metals, which are chemically bound to organic particles in the <br /> mulch, are released over time as the organic matter decomposes to release the metals to the <br /> feeder roots of the plants and the cells of the bacteria in the soil where they remain and are <br /> ' recycled. Other pollutants such as phosphorus are chemically bound to the soil particles and <br /> released slowly back to the plants and bacteria and used in their metabolic processes. Nitrogen <br /> goes through a very complex variety of biochemical processes where it can ultimately end up in <br /> the plant/bacteria biomass, turned to nitrogen gas or dissolves back into the water column as <br /> ' nitrates depending on soil temperature, pH and the availability of oxygen. The pollutants <br /> ultimately are retained in the mulch, soil and biomass with some passing out of the system into <br /> the air or back into the water. <br /> Design <br /> Each project presents different scopes for the use of Filterra®systems. To ensure the safe and <br /> specified function of the stormwater BMP,Americast reviews each application before supply. <br /> ' Information and help may be provided to the design engineer during the planning process. <br /> Correct Filterra®box sizing(by rainfall region)is essential to predict pollutant removal rates for <br /> a given area. The engineer shall submit calculations for approval by the local jurisdiction. <br /> 1 <br /> Scope <br /> 1 Supplier:Americast and/or authorized dealer of Americast Filterra®products. <br /> Engineer:the site design engineer or a representative thereof. <br /> Inspector: a representative of the governing jurisdiction or municipality for the installation site. <br /> ' Contractor:company selected to carry out the works of the contract,or authorized sub-contractor <br /> thereof. <br /> ' The Supplier,selected by the Contractor and approved by the Engineer,shall furnish Filterra® <br /> related engineering assistance required to properly size and install all components of the <br /> treatment device in accordance with the approved drawings and these specifications. The <br /> Contractor will be responsible for unloading and installation of the delivered product. The <br /> Supplier will maintain the Filterra®system for a period of 1 year after activation.Extended <br /> maintenance contracts are available. <br /> t 2/29/04 www.filterra.com <br />