The industrial composting process has evolved into a science. Gone are the days when people thought of compost as a pile of dirt and leaves rotting in the backyard. Today, composting is about making a high-quality product and, more importantly, selling it.

At compost plants across the globe, workers force air through static piles to aerate the mix and speed up decomposition. Ttimed perfectly, the facility’s composting areas are temperature-controlled throughout the process. Companies can compost more in a shorter time period because of the development of advanced airflow technology rather than just turning piles with machines.

To assure that compost products are safe, strict regulations limit levels of contaminants such as heavy metals and dangerous pathogens. Testing procedures have been put in place. Manufacturers must maintain the proper pH level, eliminate odors, and capture the liquids that are leached during the drying process. Different feedstocks, such as ash and manure, are combined with various blends of organics for different applications, many of which require distinct nutrients.

Because food waste is high in moisture and low in physical structure, it is important to mix fresh food waste with a bulking agent such as sawdust and yard waste to absorb the excess humidity .

Where Does Composting Begin?

So where do compost companies find their raw material? The answer is many places. Contracts with local farms and manufacturers of wood products provide a steady waste stream for great symbiotic relationships.

One of the most prevalent but underused sources are the neighborhoods that make up the cities and towns across the country. Only five states and around 100 cities across the U.S. have regulations in place to encourage the composting of organics rather than sending them off to a landfill. According to the University of Arizona Garbage Project the average individual American throws away 1.3 pounds of organic matter a day. That’s 474.5 pounds of organic matter in a year going into landfills that could be recycled.

In 2014, California passed Assembly Bill No. 1826 which established an integrated waste management program that requires each city and county to prepare and submit to the Department of Resources Recycling and Recovery, an integrated waste management plan. The act requires any commercial or public entity that generates more than four cubic yards of commercial solid waste per week, as well as multifamily residential dwellings of five units or more, to arrange for recycling services.

However, long before the State of California became proactive, the City of San Francisco had already established itself as a shining beacon of composting culture . Sixteen years into the program, the city collects 600 tons of yard and food waste every day, according to Governing Magazine.

But even with success stories such as San Francisco, the majority of the states and cities in the U.S. don’t have any regulations against mixing organic material with other solid waste materials. One of the main reasons being money. The cost to collect this organic matter, in addition to trash collection (the most common form of recycling), is not a high enough priority to warrant government budgets.

Separating Compostable Materials

Waste collection companies have two options for eliminating organic material in landfills.

Option one is to have the customers separate the organic material (food scraps and yard clippings) and provide a separate collection bin for pickup. The main problem with this option is that food waste ferments and odor becomes a big problem, especially if it is not in a garbage bag. This option also requires extra crew members and additional collection trucks that are dedicated to the collection of organics.

Option two, and the more likely option, is for the waste collection company to sort the organics from the inorganic material at a central location. The problem with this option is that in many communities, the collection companies don’t have a central sorting facility. The garbage trucks simply pick up the curbside waste and when the truck is full, go straight to the dump. And some of those waste collection companies that do have central receiving facilities are not necessarily set up to sort organic materials. Extra equipment will be needed to perform that task.

Automation equipment specifically designed for the separation of forestry, wood, and biomass waste is available through General Kinematics. Along with an experienced staff that can advise on the most efficient operating design. The long-term use of automated sorting equipment significantly reduces the overall operating cost due to increased automation and enhanced material purity.

Regardless of the initial cost, as landfills are becoming maxed-out across the country and the acquisition of land along with the permitting process for new landfills becomes more difficult and expensive, composting is becoming a more attractive option. In addition to avoiding trips to the landfills, composting also has a long list of environmental and agricultural benefits.

Environment

  • Water and soil conservation.
  • Protects groundwater quality.
  • Minimizes odors from agricultural areas.
  • Avoids methane production and leachate formation in landfills by diverting organics from landfills into compost.
  • Prevents erosion and turf loss on roadsides, hillsides, playing fields and golf courses.
  • Drastically reduces the need for pesticides and fertilizers.
  • Binds heavy metals and prevents them from migrating to water resources, being absorbed by plants, or being bioavailable to humans.
  • Off-farm materials can be brought in and added to manure to make compost.
  • Facilitates reforestation, wetlands restoration, and wildlife habitat revitalization efforts by amending contaminated, compacted and marginal soils.
  • Off-farm materials can be brought in and added to manure to make compost.
  • Composted manure weighs about one-fourth as much as raw manure per ton.

Agriculture

  • Long-term stable organic matter source.
  • Buffers soil pH levels.
  • Adds organic matter, humus and cation exchange capacity to regenerate poor soils.
  • Suppresses certain plant diseases and parasites and kills weed seeds.
  • Increases yield and size in some crops.
  • Increases length and concentration of roots in some crops.
  • Increases soil nutrient content and water holding capacity of sandy soils and water infiltration of clay soils.
  • Reduces fertilizer requirements.
  • Restores soil structure after natural soil microorganisms have been reduced by the use of chemical fertilizers; compost is a soil inoculant.
  • Increases earthworm populations in soil.
  • Provides slow, gradual release of nutrients, reducing loss from contaminated soils.
  • Reduces water requirements and irrigation.
  • Provides an opportunity for extra income; high-quality compost can be sold at a premium price in established markets.
  • Moves manure to non-traditional markets that do not exist for raw manure.
  • Brings higher prices for organically grown crops.
  • Minimizes odors from agricultural areas.

Reduce, Reuse, Recycle, Reward

On the bright side, according to the EPA’s latest report, the composting of food rose from 1.84 million tons in 2013 (5 percent of the estimated annual food waste in the U.S.) to 1.94 million tons in 2014 (5.1 percent). In addition, 7.15 million tons of food waste was turned into combustible energy. But sadly, 29.31 million tons of food (76.3 percent) was sent to landfills across the U.S.

Another major contributor to landfill waste is yard trimmings, of which 34.5 million tons are generated by U.S. households and municipalities each year. But unlike food waste, 61.1 percent (21.08 million tons) of this nutrient-rich bio-product was composted, and only 31.3 percent (10.79 million tons) was sent to landfills. The remaining 7.6 percent (2.63 million tons) was turned into combustible energy.  

Those numbers are based on municipal garbage figures and do not include the amount of food waste and yard trimmings composted in residential backyard compost bins.

A 2014 BioCycle study looked at 4,914 composting operations across 44 U.S. states and found that about 71 percent compost only yard trimmings and 7 percent compost food scraps.

Financially, despite the amount of labor, equipment, and testing that goes into the final packaged product, the average wholesale price for organic, non-manure compost is $20 per yard. Based on a yield of about 400 lbs. per yard, that amount averages 5 cents per pound. However, as more people raise concerns about the use of artificial fertilizers, the prices of organic compost products are starting to rise.

In short, the difficulty in increasing the amount of organic material (food waste and yard trimmings) that is diverted from landfills lies with two challenges:

1. Increasing the amount of manpower and equipment needed to collect, sort, and process the organic material into a valuable end product of compost;

2. Promoting state legislation and city ordinances that promote the participation of both residents and businesses in a program that prohibits yard trimmings from entering the trash collection system and food waste from entering the landfills.

To learn more about the composting process or GK’s expertly engineered  equipment that is used to sort and separate food and yard waste at recycling facilities around the globe, contact General Kinematics today!

Let us know how you compost in the comments!

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