Solid Waste & Recycling

Feature

On-Site Composting for Commercial Properties and Businesses

Notwithstanding the benefits, lack of SSO processing capacity in some jurisdictions can be discouraging to the IC&I sector. For example, in Ontario several processing facilities within the province -- both publicly and privately owned --...


Notwithstanding the benefits, lack of SSO processing capacity in some jurisdictions can be discouraging to the IC&I sector. For example, in Ontario several processing facilities within the province — both publicly and privately owned — are currently operating at maximum capacity; further, several facilities that are capable of managing additional material have recently faced temporary shutdowns to solve problems with odours. These shutdowns have resulted in significant amounts of SSO material being sent to landfill.

Both of these issues — the shortage of available processing capacity, and the reliability of operating processing facilities — present IC&I entities with a significant level of risk when considering the implementation of SSO diversion programs: Who will accept the material? Will it actually be composted? Are there any other options?

One potential, yet rarely considered solution, is for an IC&I entity to operate its own on-site small-scale composting facility. On-site composting eliminates the need to transport the material, often decreasing the net environmental impact of the program, and also ensures that the material is managed in a responsible manner (i.e., no capacity issues arise, so composting of the SSO is assured). On-site management also offers the flexibility to use finished compost onsite or to offer the material to employees or students for purchase, which can support company/community environmental awareness initiatives.

Technologies

Currently, there are several commercially proven on-site composting technologies available in the marketplace that are suitable for managing smaller amounts of organic waste in a cost-effective manner. Here we’ll look at two technologies:

• The Big Hanna composter distributed in Canada by Vertal Inc. of Montreal, Quebec; and,

• The Rocket distributed in Canada by MASS Environmental Services Inc. of Lakefield, Ontario.

Both of these technologies are considered in-vessel composters, meaning that the composting process occurs in completely enclosed units and the organic feedstock is composted under controlled air, moisture and temperature conditions. Let’s look at each technology in detail.

Big Hanna

The Big Hanna composter was invented in 1991 by Torsten Hultin, a Swedish sociologist, who wanted to create awareness about the way our society uses and misuses its resources and how dependent we are on our local and global environment. Susteco AB of Gothenburg, Sweden, currently develops and markets Big Hanna technology and Vertal Inc. of Montreal, Quebec is its North American distributor.

Big Hanna composters can manage all types of food waste including meat, fish and dairy products and can also handle garden waste.

The general operation of Big Hanna is as follows. First, if the composter is being used to manage a large quantity of material the waste can be pre-processed (macerated and dewatered) to reduce particle size and moisture content. If smaller quantities are being managed, the pre-processing step can be skipped. Following pre-processing (if necessary), the organic waste is then mixed with a bulking agent such as wood pellets (to absorb excess moisture).

After mixing with the bulking agent, the load is dumped into the front-end of the composter. (Ideally additional material is added on a daily basis.) After approximately 40 to 60 days, mature compost is ejected from the other end of the unit. Overall, the process results in a 90 per cent decrease in volume of the waste; even higher levels of volume reduction are achieved if the organic material is first pre-processed.

Big Hanna composters come in five different sizes capable of handling from 75 kilograms to 1,200 kilograms of organic waste per week. To date, Big Hanna composters have been delivered to more than 16 countries and installed in over 750 locations; in Canada, McGill University installed a T240 Big Hanna composter at its downtown Montreal campus in May 2010. In 2011, it’s expected that McGill’s Big Hanna will process approximately 150 tonnes of old lunches.

The Rocket

The Rocket was initially developed by Simon Webb and his father in 1998. Tidy Planet, from the United Kingdom (of which Simon is the managing director) currently develops and markets The Rocket while Mass Environmental Services Inc. markets and distributes the technology in Canada.

Generally speaking, The Rocket operates similarly to Big Hanna and is capable of managing similar types of material.

First, organic waste material is macerated and dewatered, then mixed with a bulking agent. It’s then placed in the in-vessel composter and 10 to 14 days later, sanitized compost is ejected out the other end.

One difference between this technology and the Big Hanna process is that the compost is not already matured. This disadvantage is acceptable for some organizations because of the compensation, which is speed.

The Rocket works quickly due to close control of temperature, moisture, aeration, agitation, carbon/nitrogen ratio, and microbial activity. The Rocket is mainly powered by energy from the bacteria breaking down food waste during the composting process, with only a small amount of electrical power required to automate the turning process.

The Rocket comes in four different sizes capable of processing from 900 litres to 7000 litres of organic waste per week. Based in the United Kingdom, Tidy Planet has installed The Rocket in over 200 locations throughout in that country, from colleges and universities to prisons. The first Canadian installation of The Rocket was in 2009 at Lakefield College School in Lakefield, Ontario.

Conclusion

These and other on-site composting technologies have been operated successfully for a number of years and in numerous countries. The cost-benefit of these installations may be facility dependent, that is, relative to the amount of organic material generated, and to alternative processing options (e.g., tipping fees, transportation) and/or to the avoided collection, transfer and landfilling costs where organic waste is presently disposed. These technologies offer the opportunity for some to optimally manage SSO “at home” and to achieve a number of corporate social, economic and environmental objectives.

Eric Windhorst, B.Sc., is a consultant with Stantec in Burlington, Ontario. Contact Eric at eric.windhorst@stantec.com


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