Agenda - Council - 12/14/1993 - Laserfiche WebLink

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The mixed materials will be loaded into the ten concrete bays. Temperatarc and aeration controls will maintain aerobic conditions and optimum temperatures during the composting process. A series of blowers arc mounted at intervals along the side of the outer bays. Each bay will have five independently controlled aeration zones. The blowers am controlled by an automatic temperature feedback system, as well as timers, for forced aeration. The airflow moves up from the bottom of the bays via a system of perforated pipes. Each blower is independently controlled allowing precise temperature management during the cnt/rc composting process. Automatic control of the aeration blowers is obtained by means of thermocouples permanently mounted in the bay walls. Dam is fed to a programmable micro-processor which tums the blowers on and off. This system also maintains and records temperature data for operation control purposes. Two IPS agitators will be used to process the material approximately once per day in each bay. Material will remain in the bays for approximately 17 to 21 days. Finished mater/al will be removed once daily from each bay and stored outside on an asphalt paved area. The product storage area is sized to allow for six months of storage to enable the material to be stored through the winter months. The products stored outdoors will be arranged in a windrow fashion to prevent the material from going anaerobic and generating bad odors. The odor from inside the building, generated from the composting process, will be exhausted from the building through an outdoor bio-filmr. The exhaust air will be forced through the bio-filter odor control system which breaks down odorous compounds through adsorption, absorption, and microbial degradation. The bio-~dter is composed of an aeration piping system laid in a stone plenum which is covered by approximately 3' 6" of bio-filmr media and mulch cover. The bio- filter media is a mixture of bark mulch, compost and wood chips. The building will be maintained under negative pressure using fans in order to control odorous ah' within the building. Operation of the fans will be controlled by building temperature and relative humidity. The compost will be marketed directly by [PS' marketing division. The primary end users are anticipated to be landscapers, road contractors, nurseries, State and County highway departments, etc. Any excess product will be sold to Waste Management of Minnesota, Inc. (WMMI) to use for soil enhancement of landf'dl borrow areas and soil enrichment of completed areas of the landfill. WMMI estimates that it could use all of the compost produced by the ]PS facil/ry for a m~rfimum of 4.5 years. An informational meeting was hosted by the apphcants on November 30, 1993. Nearby residents of the proposed facility, as wei1 as the R~msey City Council members, Planning and Zoning Commission members, County Board members and County staff were invited. At the meeting the following issues were discussed: operation of the plant, types of waste mater/als accepted, the composting process, material produced, odor and noise control, vehicle traffic, etc. Following the presentations, the audience was given the opportunity to ask questions and voice their opinions and concerns regarding the facility. Minutes from this meeting are enclosed. On December 7, 1993, City Staff met w/th the appldcants to discuss issues of concern. One of the issues discussed was the biofilter and what the back-up Would be in the event of equipment failure. We learned that the biofilter is designed in such a way that no more than 1/2 of thc system could fail at once. Going to 1/2 a system upon equipment failure would result in-something less than the normal 8 - 12 air changes per hour inside the building, but the number of ah- changes would be enough to keep the worker comfortable. The entire bio-filter system can be replaced in just 2-3 days.