Waste & Recycling


Compost standards need some middle ground

Ontario should develop a standard for agricultural grade compost

was reminded how far Canada’s composting industry has come in the last 25 years while listening to Compost Council of Canada’s (CCC) executive director Susan Antler, as she delivered her keynote address at SWANA’s Northern Lights conference in Winnipeg this May.

The industry has been able to carve out a niche for itself. On a kilogram for kilogram basis it outperforms all other waste diversion in Canada. They have done this by pulling up their boot straps, working hard, and as Gloria Gaynor might put it, survive.

The industry continues to evolve. On paper, agricultural use has always been the most obvious place for compost to be used. It has been difficult to develop that market mostly because ascribing value with the subsequent exchange of money has proven elusive. Part of the reason for this is that Canada’s various composting standards aim for the highest denominator of compost quality. They treat all compost alike, and as I like to say, it results in the production of compost I would happily give my own mother. Farmers, however, do not want to pay for this grade of compost.image001

There is room for a middle ground.

In Ontario, market penetration of compost into the agricultural market has been growing for the last five years. This is mostly because some facilities have developed a product farmers want and may be willing to pay for. This has been coupled with “show me” exercises, where individual compost facilities have worked with farmers to demonstrate their compost. This has been given some additional heft and credibility via agricultural trials being spearheaded by the CCC and Ontario Ministry of Agriculture and Rural Affairs (OMAFRA).

Real progress has been made. At least some of this progress is potentially threatened when changes to Ontario’s composting standards come into force this July.

Generally, Ontario’s new composting standards, released in 2012, have been well received. New compost classes, updated performance measures, and opening the door to biosolids have been helpful and represent progress. Compost facility operators were given 2.5 years to meet some of the new requirements.

The prescribed moisture content of at least 40 per cent during the curing process has raised some concern generally, but not exclusively, from those selling their compost into agricultural markets. In a perfect world this concern would have been identified and incorporated during the development of the new compost standards. While things move in real time, there are sometimes parallel streams of real time. In this case, as the compost standards were being completed, an agricultural grade compost product was being developed and tested.

This prescribed moisture content is ostensibly to facilitate compost stabilization. Compost stability is also prescribed. It may well be that the rate of stabilization slows down when the moisture content is below 40 per cent. However, if stability requirements are met why does it matter what the moisture content was during the curing process?

The current discussions about this requirement are also largely a surrogate to the real debate: the need to develop a standard for agricultural grade compost.

compostbigfourCompost produced from source separated organics (SSO) takes a long time to finish so that it can be sold into high value markets (i.e. from a compost stability and product appearance). This takes space and time, and costs money. While it may have been the original intent of every compost facility to sell into this market, the realization that their space and process did not lend itself to this, not to mention a large untapped market, led them to look elsewhere and develop an agricultural grade compost.

The extent of compost stability should really be a function of the end market. This should be different for composts that get used in a flower bed versus those applied to an agricultural field. Both approaches can lead to the production of high quality composts, appropriate to market requirements. The agricultural market, quite simply, prefers a less stable (and drier) compost and it is completely lost on me why some would view that as a low quality compost, if all other compost standards are being met.

Quite simply defining agricultural grade compost as low quality/Class B, and relegating it to additional approvals pathways, creates unnecessary barriers and costs to maintaining and growing this important market. There has been recognition in other jurisdictions, such as Europe, for the value of “fresh” (i.e. agricultural grade) and “mature” composts . It’s recognized that both can be of a high quality.

Frankly, this has shades of the upcycling/downcycling nonsense we hear about in relation to recycling. Not all organic waste needs to be converted into the highest value end compost. I think that agricultural use of compost is viewed by some as downcycling, when in fact it is the most obvious place where compost’s organic matter needs to go. Isn’t the real point that waste is being kept out of the disposal stream? And in this case, moving compost to an agricultural market is actually upcycling.

There is a fairly simple solution to all of this: The development of an agricultural grade compost standard for compost that can be freely applied to agricultural land only. This would require one fundamental change to the current standard. The current stability requirement would need to be elevated (i.e. from four milligrams of carbon in the form of carbon dioxide per gram of organic matter (on a dry weight basis) per day to some higher level) along with the prescribed curing moisture content requirement. All other standards, including pathogen reduction and metal concentrations, would remain the same.

Further best practices should be developed through the results of current Ontario agricultural compost use trials. This would include items such as storage, application rates and application methods.

It is important that only high quality composts, ones which meet appropriate standards, be produced and applied to our lands. Compost stability is an important consideration but requirements should be more nuanced to facilitate the development of different types of high quality compost. With some simple changes the implementation of unnecessary barriers can be avoided and contribute to the continued success of compost utilization.

Paul van der Werf


Paul van der Werf is President of 2cg Inc. in London, Ontario. Contact Paul at 2cg@sympatico.ca

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