Publications on Biosolids & Residuals
This section contains publications in English on biosolids, composts and ashes (from the combustion of wood residuals or biosolids). Many French publications by Marc Hébert also contain an English Summary or an Abstract. They may be found in the following pages : Biosolides, Composts et digestats, Cendres et ACM, MRF-Divers.
Biosolids & Residuals
2019 - Biosolids land application and the Precautionary Principle : SOME THOUGHTS BY A FORMER REGULATOR
Comparisons of relative risks with biosolids land applications as compared to major environmental risks with common farm practices (pesticides and pollinator decline, antibiotic resistance in animal production, emerging contaminants and GhG emissions) and with consideration to the precautionary principle. Power-Point presentation at WEAO Residuals and Biosolids Fall Seminar 2019 Mississauga, Ontario
2019 - Influence of Sludge Incineration Ash on Ryegrass Growth and Soil Phosphorus Status
Phosphorus (P) is a limited resource that could be depleted. Consequently, recycling the P contained in sewage sludge, including sewage sludge incineration ash (SIA), from wastewater treatment plants is a possibility to be explored. A greenhouse experiment using annual ryegrass (Lolium multiflorum L.) was performed with an experimental design of three completely randomized blocks of two soils and 29 treatments: one control without P and two levels of 9 and 26 kg total P ha−1 from 14 different sources: twelve SIAs (not contaminated by trace metals) from the US and Canada, one commercial synthetic fertilizer (triple superphosphate (TSP)), and one commercial rock phosphate (RP). Higher ryegrass biomass levels were achieved at the higher fertilization rate (26 kg total P ha−1) and when using the SIAs with the highest P solubility percentage (PSP) (≥ 54% of total P). The biomass increases following SIA application were as high as 29% and 59% more than the control for the sandy loam and clayey soil, respectively, but 40% less than in TSP for both soils. A similar behavior was observed for P uptake, with a maximum increase of 26% for the clayey soil, and 165% for the sandy loam soil. The ryegrass biomass and P uptake increases due to SIA application were larger than those due to RP application in the clayey soil, but similar to those in the sandy loam soil. The SIAs with a PSP of ≥ 54% significantly increased soil available P stocks and saturation. According to our findings, we conclude that the SIAs from municipal and agrifood industries have a potential for P agricultural recycling, but their efficiencies vary.
2019 - Excess soils on Québec farmland – Reducing illegal practices with Strategic communications
Presentation at the 2019 Ontario Excess Soil Conference, in Ajax, Ontario. Excess soil management and recycling in the province of Québec is quite expensive because regulations and guidelines can be very stringent and complex. Since the legal approach can be costly, and the enforcement level by Québec MOE (MELCC) has not been sufficient, illegal management options developed (a network of illegal sites). Englobe, a company involved in the treatment and recycling of excess soils in Québec and Ontario, asked Marc Hébert, a soil scientist, now retired from the Québec MOE, to do strategic communications to Québec farmers, agronomists and soil scientists. The objectives were to prevent illegal activities while developing good approaches for soil recycling on farmland.
2018 - How to achieve (Close to) zero landfilling and maximum biosolids recovery ? Lessons learned from the past and vision for the future
Von Liebig, the father of modern agronomy in the 19th century, reported that Antique civilizations that were prosperous used to recycle human manure to sustain crop production (Scott, 1968). He urged his society to rediscover this precious natural resource. However, another famous scientist at that time, Louis Pasteur, worried that it would spread newly discovered pathogenic organisms (Adler, 2002?). Since many years now, in Western countries we recycle more and «biosolids» in agriculture, with an avery low level of risks, even lower than with land application of farm (animal) manure. Since « there is nothing new under the Sun », like said King Salomon 3 000 yrs agro, if we wish biosolids recycling to grow more, we have to remember lessons from the past and not continually reinvent the wheel. We also have to be deeply rooted into the past knowledge and wisdom, even the near past, to be able to envision the future – with the lowest level of side effects (trade-off). In 2002, CCME (2012) with the help of profesionals form the private sector developed a vision for the future of biosolids in Canada. They envisioned that biosolids should not be landfilled, unless necessary, for the sake of recycling and GhG reduction. For the same reasons, CCME suggested that incineration should be more ecological. In 2018, are we close or closer to these objectives in Canada? While using the case of the province of Québec, and specially with the cities of Montreal and Quebec that are currently doing incineration, we’ll see how CCME objectives could be reached in the future. In the mean time, we will apply the Pareto principle to see if such things as zero landfilling are sound objectives, from a sustainable development point of view, not only for biosolids but for other residuals too. We will also see how land application could and should be improved, for the sake of perennial public acceptance. Lessons learned with NIMBY syndroms in Québec and Nova-Scotia will be genuinely presented. In this more philosophical than technical presentation, the speaker will also provide lessons learned from the past and tips for the new generations of stakeholders, particularly for civil servants.-Point presentation at the Canadian Biosolids & Residuals Conference, Halifax, 2018.
2015 - Long-term response of forest plantation productivity and soils to a single application of municipal biosolids
Ouimet, R., Pion, A.-P. and Hébert, M. 2015. Long-term response of forest plantation productivity and soils to a single application of municipal biosolids. Can. J. Soil Sci. 95: 187–199. After 16 to 19 yr, we revisited four experimental trials set up in the early 1990s to evaluate the long-term impact of municipal biosolids applied in forest plantations. 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 ha−1. Tree radial growth responded markedly to biosolids in the young plantations, increasing from 18 % for Pinus resinosa to 62 % for Picea glauca, and up to 700 % for Quercus sp. 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. 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.
2011 - Agricultural land application of municipal biosolids: PBDE and metal levels in cow's milk
The impact of land application of biosolids (treated municipal sewage sludge) on dairy milk quality was measured under real farm operating conditions where biosolids were applied in accordance with the regulatory framework prescribed in the province of Quebec (Canada). Milk from 14 farms receiving biosolids was sampled in the Saguenay region in December 2009 and compared with milk from 14 control farms. The tested farms had used biosolids for an average of 11 years. Statistical analysis revealed no difference in the content of inorganic contaminants (arsenic, copper, molybdenum, zinc and thallium) in the milk. These results suggest no induced hypocuprosis in dairy cows from farms using biosolids. However, the content of polybrominated diphenyl ethers (PBDEs) was higher in milk sampled from the farms using biosolids. Differences could be due, in part, to variability in dust exposure among farm buildings. PBDE levels were, however, very low (mean value of 7.2 ng/L) and remained 3 to 7 times lower than average levels recorded for various dairy products in the United States and Europe (fat content basis). These low levels could be linked, in part, to lower air deposition on forage in the Saguenay region or reduced dust contamination in the farm buildings. Based on these results, current knowledge and available data, the application of municipal biosolids under Quebec regulations would have no significant impact on PBDE exposure for consumers of dairy products produced in Quebec. The original version of this publication is titled: « Épandage agricole des biosolides municipaux : contenu en métaux et en PBDE du lait de vache » Published in VertigO – La revue électronique en sciences de l’environnement, Volume 11, Numéro 2 | 2011: http://vertigo.revues.org/
2009 - The new Canadian standards for biosolids quality (CAN/BNQ): a sound and consensus-based approach
The future of biosolids land application will be dictated by its acceptance by the general public. This is a real challenge for cities and governments, since the public generally fears even the idea of recycling human waste in the food chain. Some people base their fear on the chemical or synthetic inputs in sewers. Others fear the natural components of fecal matter (pathogens, odours). The fear is accentuated by the fact that human fecal matter is essentially a taboo subject in many modern western cultures.
2009 - Land application of biosolids in Saguenay: impacts on soil quality 16 years later
In the Saguenay region (Québec, Canada), a field study was done to evaluate metal accumulations of the soil surface layer (0-20cm) with 26 farm fields that received a mean of 7 spreadings of municipal biosolids between 1991 and 2006. This corresponds to a cumulative mean loading of 20 t/ha (d.w.b.). Spreadings were in conformity with Québec regulations and criteria. Metal accumulations were evaluated by comparing the surface layer to the 40-60 cm layer, as a control, and by using loading calculations. Cumulative spreadings of biosolids on soils had no impact on cadmium and aluminium contents, but they caused a significant increase with mercury (total) and with copper, lead and zinc (Mehlich 3) in the upper layer. However, final soil contents were well below agricultural soil reference criteria used in the province of Québec. Because lead and mercury contents of Saguenay biosolids are decreasing since 1990, further accumulations of these metals in receiving soils are likely to be lower in the future. Repeated land application of biosolids also increased the phosphorus saturation index of soils (P/Al), still most final values remained low (< 4%). This increase in soil P fertility will tend to reduce further biosolids loadings to soils, in order to respect nutrient regulations. Hence, biosolids quality, field results and trends suggest that metal quality criteria for agricultural soils will not be exceeded over the long term “5th Canadian Residuals and Biosolids Conference, Niagara Falls, Ontario” 1 (100 years), with possible exception for Cu, as it is the case with hog manure. A new approach has been published to prevent excessive soil Cu accumulations with the use of these organic fertilizers.
2009 - Agricultural wood ash recycling in Québec and in northern climates: current situation, impacts and agri-environmental practices
The use of wood ash to amend soil pH and increase soil fertility, formerly a common practice, was largely abandoned at the start of the 20th century when alternative products arrived on the market (agricultural lime, muriate of potash). Burning large quantities of wood industry residues for energy purpose contributed to increased availability of wood ash in Québec. More than 300 000 tm (wet weight) are produced yearly in the province, and approximately half of this amount was recycled as soil amendment in 2007; more than 80 000 tm being applied for agricultural purposes on 250 farms. Literature clearly shows that using ash is efficient for the correction of soil acidity and contributes to bring nutrients to crops. Ash applications to soil also generally allow increases in crop yields compared to agricultural limestone. Its economic value has been estimated between 20 and 65 $/tm for a normal ash. Its agricultural use could also reduce greenhouse gases emission, which may lead to carbon credits. However, ash quality varies, mainly because of wood type, burning conditions and water addition. In addition, alkalinity, potassium and dust contents require both environmental and agronomic precautions. Government regulations and commercial standards (BNQ) govern their use. However, this underlying framework must be complemented with best agronomic practices. Both regulations and best practices allow safe and economical use of ash in agriculture, in accordance with sustainable development.
2007 - Public acceptance and independent certification of biosolids in Canada
Reclamation of biosolids through land application generally meets 2 key components of Sustainable Development: environment and economics. Unfortunately, societal acceptance is the weakest part of it, despite the scientific evidence that risks with biosolids are low or lower than with farm manures. Beside unacceptable odor problems in some areas – that have to be dealt with – there is a general pre-conception that biosolids are at risk. This pre-conception has to deal with modern urban culture, beliefs, values and taboos. Communication must therefore be an important part of every biosolids strategy. However, since some actors of the private and public sectors are not always trustworthy in the minds of the general public, it is necessary to have some kind of independent organization that states that a given biosolids is safe. Therefore, third-party standardization and certifications of biosolids appear to be a key component to Sustainable Development. However, it is important that the certification label is well known and trustworthy by stakeholders. Pro’s and con’s of the Canadian voluntary certification of biosolids will be presented.
2007- Towards a new methodology and new criteria for the use of Salmonella as a single bacterial indicator of the quality of biosolids, compost and other fertilizing residuals
The pathogen criteria for Quebec’s land applied fertilizing residuals (FR) have undergone a series of modifications in recent years. Biosolids, composts and other residuals that are land applied for food production must not contain Salmonella in 10-g sample (wet weight). A new culture-based presence/absence method (MA.700-Sal-PA 1.0) was developed and validated to support this new criterion and to improve the detection of Salmonella. The modified semi-solid Rappaport-Vassiliadis medium (MSRV) was selected as an efficient means of separating Salmonella from interfering bacterial flora normally present in FR. The new method permitted the recuperation of low levels of spiked Salmonella (20-100 CFU per sample) in different matrices (compost, manure, wastewater, municipal biosolids and paper sludge). The presence/absence method had a detection level close to one living Salmonella cell in a 10-g pulp and paper sludge sample. The new criterion based on the absence of Salmonella in FR samples and the new detection
method will simplify the management of FR.
2006 - Development of quality criteria based on a toxicological characterization of fertilizing residuals.
Toxicity tests were used to evaluate the environmental toxicity of municipal and industrial residuals compared to cow and hog manures. The goal was to evaluate the impact of chemicals that are either potentially present but not routinely analyzed, or unknown. Four toxicity tests were used: germination and growth of barley (Hordeum vulgare), mortality of Daphnia magna, light production inhibition of the bioluminescent bacteria Vibrio fischeri, and mortality of earthworms (Eisenia andrei). Twenty-five samples of residuals and 20 samples of manures were sampled and mixed into standardized soil samples. Part of the amended soil was used for barley tests whereas a water extract of the rest was used for toxicity tests with Daphnia and Vibrio. The worm tests were performed with fertilizing residuals and manures not mixed with soil. The toxicity varied according to the amount of manure or fertilizing residual added to the soil samples. At agronomic rates, toxicity of most of the residuals was low or even negative (stimulation of barley growth). A set of toxicological tests and criteria is proposed to assess if a given residual presents an elevated toxicity as compared to that of manures. Results of this study were used by the Ministère du Développement durable, de l’Environnement et des Parcs (MDDEP) to establish toxicity criteria in its guidelines for the valorization of fertilizing residuals.
2004 - Dioxins, furans, PCBs and PAHs in eastern Canada compost
There is currently no Canadian national standard for levels of dioxins and furans in compost. The CAN/BNQ and CCME compost criteria are now under revision, and the need for a dioxin/furan criteria is being evaluated. This study presents data on the levels of dioxins/furans, dioxin-like PCBs and PAHs in 14 composts made in the provinces of Québec and Nova-Scotia. Levels of dioxins and furans were low, with an average of 9.7 ng I-TEQ/kg dry weight, and a range of 1.0 to 31 ng I-TEQ/kg. All composts met the Québec C2 criteria for dioxins and furans of 50 ng I-TEQ/kg or less, and 86% met the C1 criteria of 17 ng I-TEQ/kg or less. Dioxin/furan levels of all composts were between 10 and 300 times lower than the risk-based limit of 300 ng TEQDFP originally proposed by the U.S. Environmental Protection Agency (USEPA). On average, dioxin-like PCBs represent less than 20% of the TEQDFP total. Levels of PAH were generally low; over 96% of all analyses were below either the detection or quantification limit. Based on these results, the inclusion of dioxins/furans, PCBs, or PAHs as parameters of concern in the CAN/BNQ or the CCME compost criteria does not appear to be justified.
1991 - Mineralization of Nitrogen and Carbon in Soils Amended with Composted Manure
A study was conducted under laboratory conditions to determine the quantity of N mineralized from four composted manures incorporated into 2.7 kg of St-Jude sand or Tilly silty loam at rates of 0.05%, 0.10% and 0.20% of total N. With one exception (a hog slurry–sawdust–based compost), net cumulative mineralisation of N (Nₘₙₑₜ) during successive incubation periods increased with incubation time and with the rate of addition. After four months of incubation, Nₘ values varied from 0 to 14% of total added N. A significant third-order interaction on Nₘ values was obtained with compost type, application rate and soil type. Net immobilization of N was apparent at all incorporation rates of hog slurry compost in the two soils. To evaluate C mineralization, composts were applied at the highest N rate and CO₂ production measured periodically. One to 8.2% of total added C from manure composts was mineralized after 28 days of incubation. For each compost type, C mineralization was higher with the sandy than with the loamy mixtures. With composted sheep manure and immature cow manure compost, which contained the highest amounts of potentially mineralizable C, the highest application rate to sandy soil promoted loss of N.