MOR’s Power Point Presentation
Since 2007 MOR has provided the composting industry with consulting services and equipment to process organic waste materials into a nutrient rich soil amendment product. MOR recommends the covered ASP technology to reduce the time required by as much as 50% over conventional windrow composting methods. The covered ASP system consists of a membrane cover and positive aeration system to supply oxygen to the microbes and control temperatures and moisture for efficient/rapid composting. MOR also provides an automated control system to manage temperatures and report results to regulatory agencies.
The positively aerated, covered ASP composting technology is the latest, most cost effective way to compost any type of organic feedstock material, such as green waste, food waste, animal (diaries) waste and biosolids. Positive aeration requires less than half the power compared to negative aeration systems including biofilters. Labor costs are significantly reduced since turning requirements (at least 5 times during the first 15 days) are much less than for a conventional windrow composting system. Basically, you cover it and forget it. The MOR covered ASP systems also provide a smaller footprint since the piles have a large X-section and height thereby reducing the number of piles needed to process a specific volume rate of incoming organic material. The MOR covered ASP composting technology reduces the amount of time necessary to achieve EPA 503 pathogen requirements (PFRP). Due to the high temperatures following pile construction MOR systems generally reach PFRP within the first ten days of active composting.
Volatile Organic Compounds (VOCs) and Odor emission controls, as well as water runoff control, are important considerations for regulatory agencies. VOCs are a precursor to ozone pollution in the atmosphere and can contribute to respiratory health problems. Air pollution districts, especially non air quality attainment districts that do not meet the ozone limits as defined under the Clean Air Act, require that composting operations reduce VOC emissions by at least 80%. Odor emissions represent a nuisance to nearby residents and composting operations may be shutdown by local health authorities. Water quality runoff is also an issue with surface water pollution as the leachate generated from composting operations is high in both biochemical oxygen demand and suspended solids.
The MOR ASP addresses these issues by capturing over 80% of the VOC and odor emissions with the ePTFE micropore compost cover. VOCs and odor contaminates are trapped in a condensate layer that forms under the cover and the larger molecules are prevented from leaving the pile through the small micropore holes in the cover. Water quality is controlled by capturing the leachate in a plenum below the pile that also introduces the air to the pile with the blowers running. The captured leachate can be either returned to the incoming organic feedstock for moisture control or to treatment facilities.
The table represents a comparison of alternative composting technologies MOR uses today: 1) ePTFE covered ASP with positive aeration, 2) within-vessel aerated static pile with negative aeration and conventional windrow. The MOR covered ASP offers many advantages missing in other technologies. Most important are the lower energy and operation & maintenance costs. Although initial capital costs are higher for ASP systems (both positive and negative aeration), manpower and fuel costs are significantly greater for conventional windrow systems. Smaller site footprints are required for the positive aeration system since no biofilter is required (between 25% and 35% more site area is required for a negative aeration system due to the biofilter footprint). Both negative air ASP and conventional windrow system require more equipment intensive (negative ASP systems have complicated air manifolds and biofilter and conventional windrow systems have windrow turner machines). Finally, covered ASP with positive aerations is less susceptible to adverse weather conditions, such as pile moisture variations, biofilter flooding, and fugitive emissions.
Set it and forget it. That is MOR’s rapid composting technology. With the cover, environmental conditions within the pile are controlled to promote rapid decomposition of the organic feedstock material. The expanded polytetrafluoroethylene (ePTFE) membrane cover is placed over the compost mix (pile) and the composting process begins. Air is introduced into the bottom of the pile through air plenums (6" pipes with small orifices cast into the concrete slab), generally 2 parallel plenums per pile. Biological activity develops heat and consumes organic matter. Moisture vapor, oxygen and carbon dioxide escape through the cover (the covers breathe) while odor and VOC molecules are trapped under the cover.
MOR’s approach is a two-step process. The first or active phase is where temperatures (around 550 to 650C) are conducive to thermophilic bacteria predominating. These bacteria are responsible for destroying pathogens (PFRP). Depending on the type of feedstock the active phase can take anywhere from 3 to 4 weeks. This phase is followed by the curing temperature (less than 550C) phase mesophilic bacteria are most efficient in composting and volume reduction. The curing phase typically takes about 2 weeks.
The MOR covered ASP technology is quite simple. Each pile is individually operated on a discrete zone of the site with its own aeration plenums, blower and temperature probes. MOR uses wireless temperature probes to signal temperature data directly to the computer control system to turn blowers on/off. This simplifies pile management for the operator as there are no aeration manifolds with air flow dampers, no biofilters with moisture control systems and no heavy machinery to turn the piles.
Shown is a x-section of the MOR aeration plenum. The plenums are supplied by Buildworks Systems, Inc. The plenums are specially designed air flow devices to deliver the correct amount of air to meet the oxygen uptake rate of the microorganisms throughout the composting cycle. Air is supplied by two, 6" diameter pipes cast in the concrete slab along the center of each pile. Air enters the pile through small orifices in the pipe cap. Sizing and spacing (computerized headloss calculations are performed) of the orifices is critical to achieve uniform air distribution along the entire length of the air plenum. The aeration plenums are supplied with a special installation system to simplify the work for the contractor and to ensure that the orifices are level with the concrete slab.
The MOR ePTFE compost cover is a 3-layer system designed especially for the composting process. Essentially, it provides the optimum environment for microbial activity and decomposition of organic matter. Key to the MOR compost covers is the PTFE membrane. It controls the temperature and moisture levels in the compost feedstock mix – like an insulation blanket. It retains VOCs, odor molecules and fugitive emissions that may cause damage to the environment. It also protects the compost mix from rainfall that can retard composting and generate unwanted leachate production.
Two high strength polyester outer layers are designed to protect the delicate ePTFE membrane. They are also treated with special coatings that reduce moisture vapor transmission and provide protection from UR light. MOR ePTFE micropore compost covers come with a 5 year limited warranty.
MOR uses a customized computer interface to monitor and control the composting process. Operators have full aeration control by timer and temperature feedback to the aeration blowers. The computer interface has several screens with the status of the process: pile number, blower setting (on/off), probe temperature, pile age and current weather conditions. Operators can generate customized reports for each pile (time vs temperature) and input feedstock materials, such as source materials and bulking agents can be tracked through the system. The system also includes remote monitoring capabilities to operate from in the plant, office or even at home.
MOR has been involved with covered ASP composting since the first pilot study in Salt Lake City, UT. This pilot/demonstration study involved using an ePTFE membrane cover to control odors and demonstrate process performance with biosolids and wood waste composting. The project was a success and the client, Central Valley Water Reclamation, now composts 35 wet tons of biosolids per day on an 8-acre site in the heart of Salt Lake City. Other MOR covered ASP projects have been completed for South Utah Valley Solid Waste District, Springville, UT; Broken Sound Country Club, Boca Raton, FL; Napa Recycling and Waste Recovery, Napa, CA; Ecuador, South America; and Columbia, South America. MOR ePTFE compost covers are in service in Salt Lake City, UT; Edmonton, Alberta, Canada and Moncton, New Brunswick, Canada.
Photos showing the ePTFE membrane covered test pile and plant staff assisting with screening operations. The pilot study produced about 60 yd3 of finished, stabilized (Solvita 7) compost, meeting PFRP requirements in less than 60 days.
Photo showing the two 30’ X 120’ test pile at the South Utah Valley Solid Waste District landfill site at Elberta, UT. The pilot study tested green waste food waste and biosolids feedstock recipe mixes for VOC and odor emissions. Also vector attraction was monitored. The covered ASP technology was successful in meeting all expectations.
MOR has the capability to perform design and AutoCadd drawings for any size composting facility. Shown is the ultimate (100 ton/day biosolids and 400 yd3 of wood waste) Central Valley Water Reclamation compost facility at its off-site location near Magna, UT. The site covered 40 acres. MOR also assisted Central Valley through the environmental permitting process.
MOR performed pilot testing of Timpanogos’ aerobically digested biosolids using the covered ASP technology. The principal concern was odor emissions, since the District was facing potential litigation at its treatment plant site in American Fork, UT. The figure shows odor production rates and emissions over time. Note the especially strong odor emissions in the initial 10 days of the study. During that period the MOR ePTFE covers were able to reduce odor emissions in the range of 75%. Odor emission reductions would have been higher except for high levels of ammonia emissions which are difficult for ePTFE membrane covers to control. However, observers of the test detected no apparent odors even at the surface of the cover.
This slide is a photo of the MOR Cover Placement Machine (CPM) deploying a MOR 38’ X 175’ ePTFE compost cover. The CPM allows one operator to place and remove a cover in less than 10 minutes. Operators are standing by to attach the cover to its patented cover tie-down and emissions control system.
This photo shows the composting operation at the Broken Sound Golf course in Boca Raton, FL. It is a small composting operation using food waste and green waste obtained from the golf course and restaurant dining facilities. Recipe mix is fed to a digester for the initial active phase, then cured under MOR ePTFE compost covers. Finished product is used as soil amendment and top dressing on the golf course.
MOR’s first cover test in South America is shown in this slide. This feedstock is mixed source separated organic waste. It was set up in Quito (population over one million) to compost mixed organic waste from local collection routes. The pilot consisted of one MOR ePTFE membrane cover with a 150 m3 capacity. Material was composted in the active phase for 4 weeks, then distributed to farms to test the soil amendment value of the finished compost product.
In 2010, MOR sent an ePTFE membrane cover to the University of Medellin in Columbia. The cover was used as a demonstration to test the viability of the covered ASP technology to rapidly compost mixed organic waste materials. Shown are the students observing the cover at a composting conference at the University during the active composting phase. The test was successful in documenting the performance of the covered APS technology to produce a high quality (cured, stable) compost product within 8 weeks.
VOC emissions are of concern to air quality management districts in California. The current standard for VOC emissions is 80% removal of total non-methane, non-ethane VOCs. Here MOR is testing VOC removal efficiencies using a flux chamber to capture the VOCs coming through the surface of the ePTFE membrane cover. MOR consistently meets the 80% capture standard.