Inland Empire Regional Composting Authority Update
By Wendy Wert
On May 20, 2010, the California Water Environment Association (CWEA) Los Angeles Basin Section (LABS) presented a regional composting update at the Monterey Hill Steakhouse in Monterey Park. The featured speaker was Jeff Ziegenbein, Deputy Manager of Operations for Inland Empire Regional Composting Facility (IERCF). The IERCA was created in 2002 by a joint powers agreement between the Inland Empire Utilities Agency (IEUA) and the County Sanitation Districts of Los Angeles County (CSDLAC). The agencies have evaluated composting as an economically and environmentally sound method of beneficially reusing biosolids from publically owned treatment works (POTWs).
Jeff set the stage for the discussion by explaining the need for the project. The regional cost of processing biosolids continues to increase as available options decrease. This is largely due to the implementation of the South Coast Air Quality Management Districts (SCAQMD) Rule 1133.2, which requires fully enclosed composting operations. The ten-acre building (454,000 square feet), which once housed IKEA furniture, has become nation’s largest indoor composting facility. The total cost of the conversion was $70 million. IERCF began operations in April 2007, after working out some mechanical issues, the facility reached full capacity in late 2008. IERCF takes in 150,000 tons of biosolids from IEUA (100%) and CSDLAC (14%) and 60,000 tons of bulking agent from regional facilities, and processes it into 90,000 tons (240,000 yards) of compost per year.
IEUA processes 60 million gallons of sewage a day. Biosolids, a by-product of recycling wastewater, had been transported to recycling projects as far away as Arizona, at a cost of $40 to $50 a ton. IEUA has reported an overall savings of 25 percent by recovering these resources locally. Transforming residuals into a commodity is a four-step process that includes: mixing, active composting, screening and curing. Each day, about 400 tons of biosolids are mixed with woody materials. Active composting takes approximately 22 days before the pile is screened and moved into curing. Larger pieces screened from the compost are recycled back into the mixing operation and processed again. During curing, which takes between 30 to 38 days, the material stabilizes and is ready for distribution. Load out of finished compost is also done indoors in a sealed environment.
Air is constantly circulated through a massive biofilter to remove odors and regulated compounds before it is exhausted to the atmosphere. The 50,000 cubic yard biofilter, which occupies a 3 acre area, is sized to accommodate up to 12 air changes per hour. The wood media in the biofilter is a combination of fruit and nut tree woods and recycled pine and fir trees. A sprinkler system above the filter keeps the wood chips wet. Air handling pipes exhaust air from the facility into a giant header, 12 feet in diameter and 1,000 feet long located under the road in front of the biofilter. Regional facilities such as the Hollywood Park Racetrack, pay $2 a ton to bring the woody waste material to the IERCF rather than landfilling this resource, which has a higher cost.
The high quality compost is wholesaled in bulk to about 75 local customers who use the compost as a soil conditioner, a top dressing, or to produce a bagged product sold at local retail outlets, such as Home Depot. The bagged product is sold under the name SoilPro Premium Compost, a brand name registered by IERCA. It also has many commercial turf applications, such as for golf courses and soccer fields. SoilPro is a well-decomposed, stable and weed-free source of organic matter containing a full spectrum of micronutrients necessary for healthy plant growth. SoilPro has detailed product information available to resellers, including a guaranteed minimum nutrient analysis, a list of product benefits and application coverage data. Finished compost is sold in bulk for about $5 per cubic yard. Prices vary depending on sales volumes and product sizing. . The combined potential revenue to the program from tipping fees associated with receiving bulking agent ($60,000) and the sale of ready compost ($700,000) is expected to reach $1 million over the next couple of years offsetting operating costs significantly.
In addition to producing high quality compost, the IERCF also includes sustainable features that help to optimize process efficiency. For example there are solar panels on the roof of that generate 1 megawatt of power which supplies about 50% of the energy required to operate the facility during normal operations. Additional plans are in the works to add wind power features to the facility and thereby further reduce its need for auxiliary power supply. As the first facility permitted under AQMD Rule 1133.2, and the only fully enclosed composting facility in the nation, IERCF certainly has unique features that said it is interesting to consider that this type of operation could be located in many urban areas in the future.
Jeff pointed out how truly unique the partnership between LACSD and IEUA is and that he hopes that other municipalities will use the IERCA as a model to develop similar projects which are badly needed in the state.
