Updates from Quebec
Use of Biosolids in Quebec - Several Facts, 2015
- There are ~810 wastewater treatment facilities in Quebec.
- About 80% of these are lagoons that treat about 34% of the municipal wastewater.
- Just 13% are mechanical plants, situated in densely populated areas, but they generate the majority of the approximately 700,000 metric tonnes of biosolids produced annually.
- Biosolids are generally richer in nitrogen (N), phosphorus (P), and organic matter – but have less potassium (K) – than animal manures (read more, en français).
- Lagoon biosolids (dewatered) are less odorous compared to biosolids from mechanical plants, but their nitrogen fertilizer value and their level of organic matter is less.
- The majority of Quebec municipal biosolids are of high enough chemical quality to allow them to be used on land (read more, en français).
- About one third are composted and/or land applied, compared to nearly 100% of animal manures.
- Land application is done mostly in agriculture, on approximately 0.5% of the agricultural land in the province (versus 50% for manures).
- This use of biosolids reduces the carbon footprint of municipalities compared to landfilling of biosolids (read more, en français).
- Administratively, land application of biosolids is mostly under project approvals (there were about 450 such approvals in the most recent year).
- About 85% of farms receiving municipal biosolids (with approvals) had a compliance rate of 100% (based on 20 on-site evaluations); the rate was 75% in 2002.
How About Other Organics?
- Quebec has a goal of recycling all organic residuals from businesses by 2020.
- Nearly 300 Quebec communities provide organic waste collection service for their residents. See which ones on this interactive map.
Other Developments of Note:
- Quebec's residuals regulations has a proactive odor classification system. Now, a new guide for best practices in odor management has been published (en français).
- Research on forest use of biosolids reported in a 2015 paper in the Canadian Soil Science Society journal found that a one-time application of biosolids 16 - 19 years before had significant benefits to the tree crops and soils and "did not observe strong impacts on soil properties in an undesirable way." See more, below.
Forest use of biosolids in Quebec:
Long-term response of forest plantation productivity and soils to a single application of municipal biosolids
Rock Ouimet, Anne-Pascale Pion, and Marc Hébert, Can. J. Soil Sci. (2015) 95: 187_199
This study looked at forest management sites in Quebec that received one-time applications of biosolids 16 – 19 years prior.
Tree growth and the soil were sampled to determine the effects of a single application of biosolids applied at (liquid equivalent) rates of 0, 130, 200, and 400 m3 per hectare.
The findings (from the abstract and conclusions):
Tree radial growth responded markedly to biosolids in the young plantations, increasing from 18% for Pinus resinosa [Norway Pine] to 62% for Picea glauca [White Spruce] and up to 700% for Quercus sp. [oak]. Increases in phosphorus (P) concentrations in the tree foliage in response to biosolids could still be detected in the conifer trials. In the top 0.5 cm soil layer, organic carbon (C), total nitrogen (N), P, and copper (Cu) concentrations and pools increased, while soil compaction and bulk density decreased. In the deepest soil layer sampled (20 - 40 cm depth), the total N and calcium (Ca) pools were reduced by the biosolids treatments, while the pool of exchangeable acidity increased….
The feasibility and success of biosolids application operationally, in terms of tree growth over the long term, were outstanding in plantations where they were applied at the seedling planting stage. Yield increases were correlated to biosolids doses and were higher in poorer soils. Increased yields may be explained by nutrient loadings, especially N and P, but also by the influence of increased soil organic C concentrations and content. The increase in soil organic matter also increased soil porosity. Also, increased carbon sequestration in woody biomass and soil appear to be an added value to this practice in terms of reduction of greenhouse gas emissions, though we did not estimate carbon budgets.
Of practical interest was the fact that neither the incorporation of the biosolids into the soil by tilling nor the form of biosolids applied (liquid or dewatered) influenced yields. We did not observe strong impacts on soil properties in an undesirable way 16 to 19 yr after biosolids application. Globally, all added P accumulated in the surface horizons, suggesting an increase in soil P availability over the long term and negligible P loss to surface water for these podzolic soils. Total Cu also increased in soil surface, but not over soil quality criteria. There was evidence that loss of N and base cations occurred in the deeper soil layers….
Our observations indicate that a single application of liquid biosolids up to 400 m3 ha_1 (30 t ha_1 DM) in young forest plantations is a sustainable practice without undue risk to such podzolic soils….. As forest plantations are not directly in the food chain system, they may represent an alternative to biosolids management for communities that are against landfilling and incineration, but still uncomfortable with recycling of biosolids in agriculture.
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