Using biosolids compost in a national park

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Austen Warren Waters
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1 Banff swr o-n 09 Cvr sty pg 8-13.indd 8

by Paul van der Werf & Chad Townsend Banff produces high quality compost from its biosolids. This high quality production is expected to continue with the addition of food wastes.

in Alberta. Over the years the present in the biosolids and possibly the biosolids compost.

public health/safety and ecological integrity from the curing and up to five million annual visitors. end-use of biosolids composts.

2 by Paul van der Werf & Chad Townsend Banff produces high quality compost from its biosolids. This high quality production is expected to continue with the addition of food wastes. Using biosolids compost in a national park The scenic Town of Banff is a unique community nestled locally about the potential impacts of chemical constituents that may be within Banff National Park in Alberta. Over the years the present in the biosolids and possibly the biosolids compost. The study town has worked diligently to reduce the environmental included a Risk Assessment to help identify, assess and manage any impact created by its residents, businesses and the town s risks to public health/safety and ecological integrity from the curing and up to five million annual visitors. end-use of biosolids composts. The study has some further implications The town has been composting its biosolids with woodchip amendment since 2003; more recently, food waste has been co-composted with beautiful national park where requirements are very stringent, it can (in regarding the use of biosolids compost: if it s acceptable for use in a biosolids. theory) be used almost anywhere. In-vessel composting is undertaken at the wastewater treatment plant The project was undertaken by 2cg Inc. and Golder Associates. It (WWTP); uncured compost has been cured and used for remediation was jointly funded by the town along with Parks Canada and, given the purposes at an old landfill in the park. This site is now considered rehabilitated, but remains in use as an interim site for excess compost cur- The analysis of biosolids compost using conventional laboratory province s interest in the findings, Alberta Environment. ing and for storage. testing and ecotoxicity testing (i.e., receptor exposure toxicology) resulted in a Risk Assessment and ultimately allowed the development of The town sought to identify and justify suitable locations for both the curing and end use of the composted product, and to establish appropriate protocols/mitigations for both activities. With a limited town land Compost Quality Guidelines and other environmental requirements, a Risk Characterization. The RA tested the requirements of the CCME base, sites in the wider park had to be considered (with the agreement of and included possible risk parameters not currently captured in these Parks Canada, of course). environmental requirements. A risk management strategy was developed A study was undertaken to help find a new curing location and to to guide how compost would be cured and utilized. identify options for compost curing and finished biosolids compost utilization. While composted biosolids have been identified as an organic Compost quality material for ecological restoration in Canada s protected areas (Parks The biosolids compost produced at the Banff WWTP can be categorized Canada and the Canadian Parks Council, 2008), concerns were raised as a natural organic material. This compost meets CCME Category B compost requirements and, except for marginally Biosolids higher Se (Selenium) in some samples, meets all CCME Category A compost requirements. The metal concentrations in Banff s biosolids are relatively low. This is not unexpected as the town s industry is generally limited to tourism, making its quality of biosolids quite high. Table 1 depicts selected metal concentrations undertaken by Environment Canada in a comprehensive study of wastewater sludge (Environment Canada, 2007) and compares them to concentrations from samples collected for this study. The concentrations measured for this study October/November swr o-n 09 Cvr sty pg 8-13.indd 9

Table 1 Comparison of metal concentrations in Canadian sludges vs uncured and finished composts from the Banff WWTP Canadian Sludges Banff Banff 1995-1998 Uncured Finished Mean Concentration a

Means of 6 observations, one per months during Sept. 1993-Feb. 1994 b. Uncured compost based on 6 samples from 2008, except As which is based on 3 samples. Finished compost is based on 1 sample.

This was not unexpected as all fecal matter could be expected to have some concentration of these chemicals.

3 Table 1 Comparison of metal concentrations in Canadian sludges vs uncured and finished composts from the Banff WWTP Canadian Sludges Banff Banff Uncured Finished Mean Concentration a Compost b Compost b Metal Mean Median mg/kg DW Arsenic BDL BDL Cadmium BDL BDL Chromium Lead Mercury BDL Nickel a. Means of 6 observations, one per months during Sept Feb b. Uncured compost based on 6 samples from 2008, except As which is based on 3 samples. Finished compost is based on 1 sample. are relatively low and echo historical data. Ecotoxicity testing revealed that some endocrine disrupting chemicals (EDC) were detected in both biosolids compost and the undisturbed soil. This was not unexpected as all fecal matter could be expected to have some concentration of these chemicals. Based on limited analysis there is some indication that these chemicals are decomposed during the composting process. The literature suggests that composting can have a positive impact on decomposing these chemicals. Furthermore, the literature suggests these chemicals break down quickly in soil. The Risk Assessment and Risk Characterization exercise showed that: The leachate of uncured compost is acutely toxic to fish; There is the presence of EDC in some compost and undisturbed soil elutriate; and Choose the Leader in Container Management Solutions Recycling & Waste Collection Rehrig Pacific understands collection containers. We can also provide effective asset and participation tracking services to help you focus on what you do best your core business. Call today for more information. Come see us at the Canadian Waste & Recycling Expo Booth # Rehrig Pacific Company Customer Service info@rehrigpacific.com Web: A FAMILY TRADITION OF GROWTH, SERVICE AND INNOVATION 10 October/November 2009 swr o-n 09 Cvr sty pg 8-13.indd 10

Although the risk does not appear great, the curing area should be kept away from recreational areas to avoid exposure to compost or leachate by the general public; and Although the risk does not

4 The use of undiluted compost has a negative impact on plant emergence and plant growth. There were a number of Risk Management recommendations for a new curing site that emanated from the results of the Risk Assessment including: The curing area should be set-back from surface water; Although the risk does not appear great, the curing area should be kept away from recreational areas to avoid exposure to compost or leachate by the general public; and Although the risk does not appear great, the curing area should not be readily accessible (e.g., fenced) to terrestrial receptors to avoid exposure to compost or leachate. None of these outcomes was unexpected and essentially reaffirm current knowledge and well established best practices to mitigate these risks. October/November swr o-n 09 Cvr sty pg 8-13.indd 11

Ultimately an isolated, previously disturbed site on the outside of town was selected for curing. This site featured old lined sewage lagoons.

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Curing site selection It was determined that about 0.4 ha (one acre) of space was required to manage curing, screening and finished product storage.

6 Curing site selection It was determined that about 0.4 ha (one acre) of space was required to manage curing, screening and finished product storage. A number of previously disturbed sites (gravel pits, etc.) were examined in the Banff area and in the park that could be used to cure compost. This included examination of space at the WWTP, a site outside of town used to dispose of clean fill, as well as some other sites. The goal was to find a curing site that afforded proper curing but at the same time was close to areas where the compost could be used. Ultimately an isolated, previously distur b ed site on the outside of town was selected for curing. This site featured old lined sewage lagoons. The reasons for this selection included: Option to contain leachate generated during curing process; Option to fence the curing area; Close proximity to WWTP; and Odour contained well away from visitors and residents. References Report Fate and Significance of Contaminants in Wastewater Sludge Generated at Municipal and Other Publicly owned Wastewater Treatment Facilities (Environment Canada, 2007) Principles and Guidelines for Ecological Restoration in Canada s Protected Natural Areas (Parks Canada and the Canadian Parks Council, 2008) This site is currently in the design phase; it s expected that an impermeable curing pad will be constructed in early It was recommended that two main compost products be produced: a Landscaping Grade and a Reclamation/Remediation Grade, with about half of annual compost production dedicated to each use. Conclusion Banff produces high quality compost from its biosolids. This high quality production is expected to continue with the addition of food wastes. The risks to curing and utilizing this compost were assessed and the means to mitigate these risks have been identified and discussed. A strategy to cure and utilize this compost has been developed. Banff and Parks Canada should be able to build on the success of their shared responsibility in composting and utilizing biosolids compost, to continue to contribute positively to maintaining and improving the ecological integrity of the national park. Paul van der Werf is president of 2cg Inc. in London, Ontario. Contact Paul at Chad Townsend is Environmental Coordinator, Planning & Development with the Town of Banff, Alberta. Contact Chad at chad.townsend@banff.ca Brampton (800) Edmonton (866) Calgary (866) Saskatoon (800) Winnipeg (866) Montreal (800) Grande Prairie (877) Atlantic Provinces (902) October/November swr o-n 09 Cvr sty pg 8-13.indd 13 15/10/09 11:35 AM

Winnipeg Biosolids SAC Meeting #2. November 18, 2013

Winnipeg Biosolids SAC Meeting #2 November 18, 2013 Outline Selection Criteria Biosolids Trends and Options Compost Land Reclamation Landfill Selection Criteria Selection criteria that must be included: