COMPOSTING 101

What is composting?
What can be composted?
Composting technologies
What's so good about compost?
EPA Region IV overview

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Generally, compost feedstocks are waste products … materials no one else wants or needs.  From both an environmental and an economic viewpoint, recycling wastes for use as raw material in the manufacture of compost products makes sense.  But beyond the obvious benefits of compost manufacture are the equally impressive advantages of compost use in conjunction with or instead of synthetic products for farming, gardening, and landscaping. 

A.  Benefits of making and using compost

1.   Backyard composting is, without a doubt, the environmentally correct thing to do, since it closes the loop at the source.  But the percent of composting households is thought to be small,[1]  and a 1999 report by the New York City Department of Sanitation admitted backyard composting will not have any measurable effect on diversion in New York City, but is a good way of promoting waste awareness among residents. 

If it’s true that at least one-quarter of the 356 billion pounds of food produced every year in this country – 89 billion pounds -- winds up as garbage,[2] then putting those nutrients back into food and fiber production where they belong will require a monumental mobilization and infrastructure development effort far beyond the scope of backyard composting.  Fortunately, the trend of U.S. households toward more pre-packaged, take-out, and restaurant meals[3] is helping to consolidate and centralize food waste generation and enabling the collection of more waste from fewer generation points … essential to making 100% recycling for organics[4] a practical, economically viable goal.

2.  The toxic soup created when the ooze of decaying matter mingles with the residues of household chemicals and other toxins draining from modern landfills is expensive to treat and manage. While the World Bank says reductions in landfill operating costs of 35-47 percent may be possible through bioreactors and subsequent cost recovery from sold power, compost supporters could argue it would be a lot less trouble and reduce costs by at least 40-70 percent if biodegradables didn’t go into landfills in the first place.

3.  Fertilizer manufacture is one of those industries that has slipped quietly overseas in the past decade.   In 1995, U.S. farmers imported 21.7 tons of fertilizer products.  Eight years later, imports topped 31.3 million tons, with total NPK use holding steady over the same time period[5].  Compost is a good soil conditioner, but in the past, compost’s cost made it an impractical nutrition source for large scale users.  However, in 2005, with chemical fertilizers at $_____ per ton, compost as an NPK can compete than chemicals.  Farmers can save money and dramatically improve their soils by switching to a compost-based cropping system.

4.  Even if landfill managers can extract methane gas generated by decomposing organics, even if organics can be obliterated through incineration, even if it’s possible to sprinkle fairy dust over a landfill and make all of the stinking garbage go away … does that mean we should do it?  Our soils are lifeless, chemically dependent, and gasping for the benefits only compost can deliver.  Does it make sense to bury, burn, or otherwise destroy millions of tons of compostables every year while millions of dollars are being spent on imported nutrition for food and fiber crops? 

5.   Composting is a recycling technology, a strategy for reducing the fill and replacement rate of landfills and associated costs, and a manufacturing system for superior soil amendments.  The recycling and landfill aspects get a lot of press, but beneficial reuse does not, which may be one reason why biodegradables are still being buried in landfills.   If every farmer would try compost on just one field, s/he’d be convinced of its regenerative power for depleted soils, and putrescibles could disappear from landfills almost overnight without legislative or regulatory impetus.  Here are just a few of the benefits compost delivers:

Microbial activity.  Microbes in the soil positively impact nutrient uptake.

Neutral pH[6].  Some compost products fall within the “ideal” range for soil pH – 6.0 to 7.5, typical range for all compost products is 5.0 to 8.5.  A compost pH beyond the typical can be beneficial, like 4.0 (acidic) compost for blueberries or a high pH (alkaline or basic) as a substitute for lime.  But be judicious in their use and be aware that pH levels on the far extremes of the pH scale are hazardous and include things like battery acid (ph=0) and liquid drain cleaner (ph=14).

High CEC.  Improves the soil’s capacity to hold onto nutrients, keeping at the root zone where plants need them instead of leaching to groundwater or running off into rivers and streams.

Moisture retention.  Compost’s ability to retain moisture is legendary.  This not only reduces watering requirements and helps compost amended fields, crops, and lawns weather dry spells, but cuts back on topsoil loss due to erosion.  What’s not so well know is it’s ability to do just the opposite during periods of excessive moisture, wicking water away from root systems over-saturated due to heavy rains or floods.

Pest and disease resistance.  Compost use boosts plant resistance to pests and diseases  Widespread adoption of cultural practices including compost by large-scale, conventional produce growers in southeastern North Carolina have shown it to be an effective, cost-competitive replacement for the banned fumigant, methyl bromide, too.

B. Class A compost vs. Class B land application

A storm is brewing over the land application of Class B biosolids (sewage sludge), a practice currently approved by the EPA. 

Land application has long been used as a disposal method for biodegradables, mostly, sludges and manures.    When properly managed, land application has much in common with sheet composting (Section 1-3) and, in some areas, is still the most affordable disposal option for waste generators.

However, land application has several big problems:

·   A poorly managed land application program can be a nightmare for the host community.  If the waste is not immediately incorporated into the soil, odors and flies escalate.  While Class B sludge from sewage treatment plants receives some treatment before land application, pathogen levels are still a concern and Class B sludge has many restrictions placed on its application.  Raw septage (from septic tanks and portable toilets) may not receive any treatment.   On the other hand, Class A compost has been subjected to a higher level of management to neutralize pathogenic threats and, as far as the EPA is concerned, many be used anywhere at anytime without restriction.

·   Contamination of ground and surface waters is possible if maximum land loading rates for Class B sludge are exceeded or heavy rains hit prior incorporation.

·   In some areas, creeping urban sprawl has turned into a mad homesteaders dash.  Appropriate sites for land application are getting hard to come by as farmers sell out to developers and new neighbors reject the aromas of agriculture.   Costs escalate when generators are forced to transport to sites further and further away from city centers.

Fortunately, composting offers an economical alternative to land application programs, because sludge and other high moisture organics have been successfully composted for years.

While there are visual indicators of stability, the EPA insists on laboratory testing (see Section xxxxx) to protect public health.  Again, compost products that meet or exceed EPA Class A requirements are held to a higher standard than Class B.