Ontario generates about 13 million tonnes of waste each year – enough to cover the entire surface area of the City of Toronto with 15 centimetres (cm) of refuse. Of that total, about one-third is comprised of organic residuals and, therefore, compostable. Although some municipalities have been collecting and composting leaf and yard residuals and/or promoting backyard composting for many years, much of this material is still being disposed of in Ontario’s landfills. Over the past decade, however, faced with increasing waste disposal costs, rapidly declining landfill capacity and growing public pressure to increase waste diversion, more and more municipal decision makers are deciding that composting organic residuals is arguably the best way to maximize diversion.

Although this interest in composting for waste management purposes is relatively new, composting as an agricultural process is not; it has been practiced for millennia. The Egyptians composted animal manure with straw and farmers in medieval Europe used compost as fertilizer for their crops. In North America, composting provided an estimated 90 per cent of farmers’ fertilization needs until 1950, after which inexpensive, easier-to-apply, and highly effective commercial fertilizer resulted in that figure dropping to about 1 per cent by the end of the century. During this chemical era, the art and science of composting has been kept alive by proponents of organic farming.

Composting is a natural process, whereby organic materials (i.e., those derived from living organisms, such as plant tissue, animal flesh, wood, paper fibre, etc.) are broken down by microbes in the presence of adequate moisture and air. The result is compost – a dark brown, crumbly material, similar in appearance to good soil. If a particular compost doesn’t have a pleasant, earthy smell, it has either been improperly made or it is not yet finished, or “mature.” The most common composting process currently used in Ontario is aerobic composting. The term “aerobic” means that the process requires oxygen. Other types of composting practiced on a commercial scale in Ontario include: vermicomposting (composting with worms), which is also aerobic but has no thermophillic stage (see below); and anaerobic digestion, a process that takes place in the absence of oxygen and that also produces biogas, which has value as a source of energy. The focus in this article is on aerobic composting.

The aerobic process includes a “self-heating” (thermophillic) stage characterized by high temperatures (40-70^o C). This is important because the high temperatures destroy both pathogenic organisms and weed seeds. During the final curing stage, the cooling compost is colonized by many different beneficial soil organisms, from bacteria and fungi to arthropods and composting worms.

Contents 1 The Value of Compost 2 Composting and Compost Use in Ontario 3 Promoting the Value of Compost 4 ECO Comment

The Value of Compost

The main ingredient in mature aerobic compost is humus – a mixture of various related and complex organic substances that are relatively stable (i.e., do not degrade easily in soil). Humus provides both food and habitat for beneficial soil microbes. The latter slowly convert part of the humus into nutrients in a form available to plants. This “nutrient cycling” is fundamental to the health and fertility of natural ecosystems. The remainder of the humus remains in the soil, providing many other benefits, including the following.

• Disease suppression: Plants are protected from disease by the large and diverse number of beneficial soil microbes that are fostered by the high humus levels. The disease organisms are suppressed, out-competed, or simply crowded out by the beneficial organisms.
• Soil structure: Microbes build soil structure. Bacteria secrete glues and fungi build threads that, working together, bind the soil into varying sized clumps, or aggregates. The result is porous soil that drains well, resists compaction, remains aerated, and holds plant-available water and nutrients in its micro-pores.
• Water conservation: Humus helps both clay and sandy soils by providing porosity for the former and increased water holding capacity for the latter. Most soils have anywhere from 1 to 10 per cent organic matter content. An increase in just 1 per cent (e.g., from 2 per cent to 3 per cent) allows a typical soil to hold an extra 14.5 litres of water per square meter.
• Carbon sequestration: A 1 per cent increase in organic matter means that 132 tonnes of carbon dioxide have been sequestered, or removed from the atmosphere, for every hectare of soil. Most of the discussion in Ontario on carbon sequestration in soils as a mitigation measure for climate change focuses on land management methods, such as no-till agriculture. However, the scientific literature confirms that adding compost to soil not only sequesters carbon, but does so more rapidly than any other method with the exception of biochar (see Biochar: The Promising Future for an Ancient Process in this Annual Report).

Biological Methods for Managing Soil Systems: Two Real World Examples

Slowly but surely, compost’s high end potential is being realized in real world applications. At Harvard University, for instance, the people who look after the grass, flowers, and trees on the 32-hectare campus have discovered that, by using compost scientifically, they can manage the living landscape cost effectively without the use of either pesticides or commercial fertilizers. To do this, they focus on feeding and managing the soil microbes to optimize the soil for individual plant species. The result has been virtually no disease, few weeds, less soil compaction (with grass roots reaching 20 cm deep), a 30 per cent reduction in water use, and greener turf. The Town of Wolfville, Nova Scotia, is another convert to this “biological” approach. The Town makes its own compost from leaf and yard waste and applies it on two full size soccer fields, one mini soccer field, and three parks (including the gardens). No fertilizer or pesticides are necessary. Like Harvard, the town’s composts are tailored for specific purposes. As a result, its soils have been “redesigned” to help turf and plants out-compete the weeds and resist disease. The Town’s parks manager reports, “overall our turf is lusher, greener, and has less broadleaf weeds. We have no disease at all and very minimal insect problems, which are easy to control with organic methods.”

Over the past couple of decades, scientists have been increasing their efforts to develop biological methods for managing soil systems, with increasingly impressive results (see box above). They are working with microbes that naturally suppress certain diseases and are finding ways to inoculate compost and compost extracts with these biological antidotes. They are also examining the soil ecology in different ecosystems, such as prairies and forests, to determine which microbial communities work best for different groups of plants, from quick growing annuals to long lived perennials. Because compost is the perfect vehicle for delivering, enhancing, and sustaining beneficial soil microbes and their communities, the opportunities for compost to play a major role in sustainable agriculture and all other soil-based endeavours will grow in tandem with these new discoveries and applications.

Composting and Compost Use in Ontario

The composting of Ontario’s municipal and industrial, commercial and institutional (IC&I) organic residuals happens at two basic scales of operation. Most material is processed at municipal or commercial facilities (usually large scale), and is regulated by the Ministry of the Environment (MOE) under Part V of the Environmental Protection Act (EPA). Lesser portions of the residuals are processed on-site at IC&I locations (usually small scale), at community sites (e.g., community gardens), or in the backyards of Ontario residents. These smaller operations are not specifically regulated (although general environmental protection legislation applies), provided that the residuals are generated and processed at the same site.

Many Ontario municipalities, including Ottawa, Hamilton, and Toronto, have established “green bin” programs to collect organic residuals at curbside for processing at centralized composting facilities.

These programs, however, have not been universally popular or successful. Some of the problems experienced include:

• local opposition when siting facilities;
• operational problems at facilities, particularly high odour levels;
• contamination of residuals, lowering product quality;
• problems with pests, particularly raccoons, getting into the green bins; and
• generally mixed levels of public acceptance and participation.

These issues have resulted in composting receiving considerable negative media coverage. In addition, many people do not see the value in compost and wonder why we do not simply burn organic waste to produce energy. People who hold this view believe that biomass energy can replace fossil fuels, while compost is just a low value soil amendment. Moreover, as more landfills collect and use methane gas to produce electrical power, some see composting organics as a waste of money when they can generate “free” energy in the landfill. These types of views, commonly expressed in the media, highlight the lack of understanding of the value of compost among both the public and many in the waste management industry.

In 2006, Statistics Canada reported that 732,000 tonnes, or about 17 per cent of Ontario’s organic residuals, were diverted from landfill (mostly to composting facilities.) The ECO expects that the diversion rate was considerably higher in the first half of 2010. Waste Diversion Ontario (WDO) surveyed municipalities in 2008 and found that more than 800,000 tonnes of organic residuals were collected by municipal programs alone (a 21 per cent increase over 2007). Figures provided by MOE in 2010 for approved composting facilities indicate processing capacity limits of up to 1.5 million tonnes of input annually, adequate to handle about one-third of the suitable organic residuals generated annually. If a substantial proportion of this capacity were to be utilized, it would represent a significant increase in diversion.

It is difficult to know, however, how all of the resulting compost is used. No compost market data exist in Ontario. Other jurisdictions report that most of their municipal compost is either given away to residents or sold at a fairly low price to landscapers and topsoil blenders. This is probably also true in Ontario. A few commercial composting facilities use only very clean sources of material, such as food processing residuals, to produce high quality products for specific markets, but to date these are the exception. Most facilities focus on revenues from waste management tipping fees, rather than from the sale of the product. This is particularly true of facilities processing “green bin” residuals.

The Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA) reports that very little, if any, municipal or IC&I compost is used on agricultural land. The ministry suggests that it is difficult to assess compost’s fertilizer value, as compost provides few nutrients directly. Rather, it increases the ability of soil microbes to convert mineral and organic nutrients into plant-available form – a steady but longer-term process. Further, the ministry states that cost is a primary barrier. Off-farm compost costs more than manure or compost produced from crop residues, and farmers cannot justify additional costs when compost’s benefits (in terms of dollar values) are unclear.

These issues highlight one of the most significant barriers facing composting: a lack of knowledge and/or appreciation of the real value of well-made compost. Currently, many municipalities choose to produce compost that, at least in terms of the biological and agronomic parameters discussed in this article, is of less than optimum quality (although these compost products do meet the province’s stringent interim guidelines for contaminant levels). The focus tends to be on collecting as much material as possible, thus increasing waste diversion rates, rather than realizing the potential of producing a higher value product. Similarly, if a commercial compost facility could achieve a significantly better price for a higher quality product, managers would be more inclined to invest the money required to achieve that higher quality.

To complicate matters, however, the growing demand for biomass to replace fossil fuels as an energy source will create economic competition for organic residuals, making energy generating options more appealing than composting to municipalities and large IC&I generators. Sound government policy is needed to overcome this barrier, which is crucial to the future of compost.

Promoting the Value of Compost

The ECO proposes that a strategy to promote the value of high quality compost in the marketplace would address many of these concerns. The goal should be to create, over time, a greater level of understanding of compost’s real value and, hence, a higher market price for good quality compost.

If this could be achieved, it would:

• create incentive for both the public and private sector to build new facilities, increasing waste diversion and saving landfill space;
• make financing of facilities easier and mitigate financial risk;
• allow composting facilities to reduce tipping fees and thus better compete for organic residuals with energy production facilities;
• drive an increase in product quality, including the development of specialty composts for high

value end markets; and,

• create a better public image for compost, which would help to promote both backyard composting and more compost use by homeowners.

The ECO recognizes the many difficulties inherent in trying to use government policy to integrate environmental benefits into market pricing. It can only be done indirectly, by creating awareness, reducing barriers to use, etc. In 2009, MOE posted a proposal for revised composting guidelines on the Environmental Registry ([1]). This is a very good start; if implemented as proposed, the guidelines will create three distinct quality levels. Removing unnecessary regulatory restrictions is one important way to increase accessibility and demand.

Several other of MOE’s recent regulatory and policy initiatives indicate that it shares the ECO’s view regarding the importance of compost and composting. Examples include: the recent changes to the rules for application of non-agricultural source materials on land (see Sewage Biosolids: New Rules for Use on Agricultural Land in this Annual Report); and the clear position, set out in O. Reg. 359/09 (Renewable Energy Approvals under Part V.0.1 of the EPA), that for the purposes of renewable energy projects, processes that produce material for the soil (e.g., composting and anaerobic digestion) constitute the highest priority end uses for organic residuals.

However, at least two recent decisions appear to undermine this positive approach. First, the inclusion of compost in the new Municipal Hazardous or Special Waste Program Plan; and second, the requirement for smaller landfills to put in systems to collect landfill gas (see Landfill Gas Collection and Control Regulation in our 2008/09 Annual Report). In the first case, a hazardous waste program that targets compost flies in the face of scientific logic (properly made compost is in no way hazardous or in need of special handling) and sets up an artificial and completely unnecessary barrier to the development of strong markets for high-quality compost. In the second case, the new landfill requirement may have negative consequences for composting, as municipalities may feel that removing organics from the waste stream is counter-productive if they have invested significantly in energy production from landfill gas.

ECO Comment

Given the policy contradictions noted above and the inevitable increase in demand for organic residuals from a surge in green energy projects, the ECO believes that Ontario needs an overall organic residual strategy anchored by a strong set of composting policies. The following are three areas of compost policy development that should be considered.

1. A provincial government-wide commitment to using compost.
2. A comprehensive strategy and implementation plan for identifying, clarifying and promoting the value of compost, including:

• public education programs on the value of compost as a key element in sustainable lawn care;
• demonstration projects for different potential compost markets;
• research projects with universities and the private sector to better quantify specific compost benefits, particularly those associated with (i) the biology of compost and its effects on soil ecology, and (ii) possible compost synergies with the use of biochar in soils (see Biochar: The Promising Future for an Ancient Process in this Annual Report); and
• a strategy and plan for promoting backyard, community-scale, and on-site IC&I composting, since these are extremely cost effective and potentially environmentally superior options.

1. A plan for financing the above initiatives.

With respect to financing issues, a comprehensive stewardship program for organics may not be workable, as the principal stewards (growers) have no control over the “design” of their products. Similarly, in terms of regulation, measures such as a disposal ban on organic residuals might be better left for a later date, as bans do nothing to ensure the quality of compost and may, in fact, push quality (and price) to lower levels by flooding the marketplace with inferior product. Two financing options that merit current consideration are disposal levies and carbon credits, although care must be taken not to allow either mechanism to have a negative impact on compost quality.

With respect to carbon credits, the government should consider investigating and, in future negotiations with other jurisdictions, supporting credits for both compost production and compost application by farmers and turf managers. The latter could be part of a broader set of protocols aimed at increasing soil carbon.

All of the above presupposes that compost has a “champion” in government – a ministry that assumes the primary responsibility for achieving compost’s full potential in Ontario. In that regard, MOE is not the only ministry with a relevant mandate. OMAFRA is already involved in research projects involving the addition of municipal compost to agricultural crops, and other ministries may have responsibilities that intersect with composting. All relevant ministries could be involved in the development of the organics residual strategy, as well as the composting policies at its core. However, the ECO suggests that MOE assume the role of compost champion and take the lead in instigating and managing this initiative.

Redefining conservation must include rethinking our definitions of “waste”. Organic residuals are not wastes; they are key resources for sustainable soil management practices. These in turn underpin the sustainability of our water resources, our food supply and our climate. In the ECO’s 2008/2009 Annual Report (Soil: Our Eroding Asset), the ECO pointed out that Ontario’s soils receive neither the quantity nor the quality of attention that their vital importance deserves. Since compost is an essential element in any broad strategy to conserve and enhance soils, the development and implementation of a multi- ministry organic residual strategy would be a good step in rectifying this deficiency.

Recommendation 12: The ECO recommends that the Ministry of the Environment lead a multi-ministry initiative to create a new compost-centred policy vision for the management of organic residuals in Ontario.

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This is an article from the 2009/10 Annual Report to the Legislature from the Environmental Commissioner of Ontario. Redefining Conservation: Table of Contents Information on the official document and its release.

Citing This Article:
Environmental Commissioner of Ontario. 2010. "Compost: Appreciating Nature’s Sense of Humus." Redefining Conservation, ECO Annual Report, 2009/10. Toronto, ON : Environmental Commissioner of Ontario. 135-140.