Potentiel de recyclage agricole des boues d'épuration et des cendres de combustion des boues municipales ou agroalimentaires en Amérique du Nord

Authors: Joseph, Claude-Alla
Advisor: Gallichand, JacquesKhiari, Lotfi
Abstract: Biosolids and sludges incinerated ashes (SIA) are valuables sources of nutrients (N, P) and organics matter. During the last decades, a considerable amount of research has been done on biosolids nutrients availability after their application onto agricultural land. But these studies are focused on specific products and performed under different experimental conditions, generating very different results. Therefore, so far, no model has been proposed to predict nitrogen and phosphorus plant availability for biosolids land application. Although the chemical characterization of SIA has been widely examined, there are only a few studies regarding crop responses to this source of P. This study has generated prediction models to evaluate nitrogen and phosphorus plant availability in these products in order to improve their agricultural recycling and avoid environmental risks of pollution. Data were collected from national and international literature in order to design two models to assess and classify nitrogen and phosphorus availability in SIA. Twelve SIA from mono-incinerators located in Canada and the USA were tested for their fertilizing potential in a greenhouse experiment. Then, random forest modeling was used to find out an indicator of prediction of SIA phosphorus availability. Depending on the C/N ratio of non-composted by-products, six categories were defined. i) high mineralization: +66 % relative N effectiveness (RNE) and 5 ≤ C/N, ii) moderate mineralization: +33 % RNE and 5 < C/N ≤ 16, iii) low mineralization: +9 % RNE and 16 < C/N ≤ 38, iv) low immobilization: −9% RNE and 38 < C/N ≤ 90, v) moderate immobilization: −27 % RNE and 90 < C/N ≤ 140, and vi) high immobilization: −55 % RNE and C/N > 140. According to the total molar concentration of Al and Fe in biosolids, phosphorus availability were divided into 4 classes: i) very high (230-400 mmol kg-1), ii) high (401-1100 mmol kg-1), iii) medium (1101-2800 mmol kg-1), and, iv), and low (2801-5132 mmol kg-1). The biomass increases following an 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 for the triple super phosphate (TSP), for both soils. The ray-grass biomass and P uptake increases due to SIA applications were larger than those of rock phosphate (RP) application in the clayey soil, but similar to those in the sandy loam soil. 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 SIA with a PSP of ≥ 54% significantly increased soil available P stocks and saturation. The random forest modeling shows that oxalate extraction is a practical indicator of prediction of SIA phosphorus availability. Also, this modeling shows that SIA Al content is the most influent factor of this availability.
Document Type: Thèse de doctorat
Issue Date: 2019
Open Access Date: 3 October 2019
Permalink: http://hdl.handle.net/20.500.11794/36796
Grantor: Université Laval
Collection:Thèses et mémoires

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