Health and Safety Requirements for Enclosed Composting Facilities

I have previously discussed implementation of new regulations for composting that require potentially odorous waste to be received, processed and composted in an enclosed space. The primary goal of these regulations is for social and environmental acceptance – particularly odor control and leachate control. There are important health and safety issues that may be triggered with this type of regulation. The first relates to safety regarding the building or enclosure and electrical components. The second relates to operator or worker health and safety.

I will give you an example of how implementing regulations have impacted safety with composting facilities. In the mid 90s, British Columbia experienced significant odor complaints regarding composting facilities preparing substrates for mushroom production. These operations were located outdoors in a high rainfall climate and odors carried for several kilometers. The BC Ministry of Environment subsequently implemented the Mushroom Composting Regulation, which required that mushroom compost production occur in a negatively ventilated enclosed building with odor control. Within two years of implementing this regulation, two mushroom composting facilities collapsed due to corrosion of the galvanized truss plates. Fortunately, no one was hurt.

What had happened was that owners of the composting facilities responded to the regulation by enclosing their existing buildings which had not been designed for enclosed operations. This is a prime example of the effect of regulations intended to be positive for social acceptance in terms of odor and water quality, but may have negatively impacted worker health and safety had there been anyone inside the buildings at the time of collapse. The other safety concern is with electrical systems inside these facilities.

The safety concerns can be easily mitigated by using corrosion resistant building structures (hot dipped galvanized or better), and by placing as much of the electrical outside of the building or protecting it as much as possible (PVC fixtures are subject to corrosion by the high ammonia and therefore not recommended).

With the example of Foundation Organics compost facility that we designed in 2011, the building was constructed using hot dipped galvanized trusses with replaceable tarpalene panels. There are no electrical fixtures inside the building – the aeration blowers are outside the building, and lighting or electricity for repair or maintenance can be brought in as required.

Enclosing the composting facility also potentially impacts worker health. The first important safety precaution is to have appropriate signage restricting entry to authorized and trained personnel. It is recommended to consult with local worker health and safety organization to determine what protective mechanisms may be necessary.  In the case of Foundation Organics, the owners consulted with Worksafe BC, who provided instrumentation and advice on worker health and safety. In some cases, this consultation is of mutual benefit, as many worker health and safety organizations are not completely familiar with all of the potential risks associated with organic waste management. A very significant example relates to a number of persons who have died in composting facilities due to hydrogen sulphide. It is very important for everyone (workers and worker health and safety organizations) to understand this potential risk and what triggers concern. With the Foundation Organics facility, the facility was subjected to conditions that may cause formation of hydrogen sulphide and continually monitored to determine if there was potential risk. Fortunately, there was no risk in this process.

As we think about reducing the risk of odor in our communities, we we also have to think through the implications of our management changes.

 

 

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