Exploratory study of polycyclic aromatic hydrocarbons occurrence and distribution in manure pyrolysis products

Abstract

The occurrence and distribution of polycyclic aromatic hydrocarbons (PAH) have been investigated in the products derived from the pyrolysis of pig manure at low temperatures (<550 • C) in a fixed bed reactor. The focus was on the sixteen PAH identified as priority pollutants by the US Environment Protection Agency (EPA). The pyrolysis does not generate a significant additional amount of EPA-PAH to that existing in the original pig manure, under the operational conditions studied (<550 • C). While the total EPA-PAH yield does not indicate a notable dependence on the pyrolysis temperature, the EPA-PAH distribution among the three pig manure pyrolysis products as well as the speciation changed significantly with the temperature. The proportion of heavy PAH species increased as the temperature increased. The initial EPA-PAH in the manure samples plays a significant role in both their concentration and speciation in the biochar. The relationship of the EPA-PAH concentration and speciation in the biochar with those of the raw material was corroborated with a cow manure sample and the biochars obtained from its pyrolysis. For this reason, feedstocks with low EPA-PAH concentrations are recommended in order to obtain biochars with concentrations below the maximum allowed threshold established for their use as a soil enhancer by the International Biochar Initiative (IBI) and in the European Biochar Certificate.

Industrial CO2 Capture by Algae: A Review and Recent Advances

“…The combustible mass of microalgae consists of C 32.1%, H 4.8%, N 5.3%, O 22.1%, S 0.5%. This high ash content has a considerable influence on quality of biofuels [115,[119][120][121][122]. The content of proteins and lipids in the feedstock was 27.8% and 11.5%, respectively.…”

Biochar can mitigate co-selection and control antibiotic resistant genes (ARGs) in compost and soil

“…Biochar feedstock, type of reactor, and production temperature are the most important. The yield of PAHs in biochar has no significant dependence on pyrolysis temperature, but its distribution and speciation changes with temperature as high molecular weight PAHs was found to increase in biochar with increase in production temperature ( Adanez-Rubio et al., 2021 ). PTEs appears to increase with rise in temperature irrespective of other conditions while the yield of PAHs is affected by all production conditions ( Keiluweit et al., 2012 ).…”

“…Biochar from various plant and animal sources contain PAHs ( Fabbri et al., 2013 ; Quilliam et al., 2013 ), PCBs ( Luo et al., 2014 ), dioxins ( Luo et al., 2014 ) and PTEs ( Gondek et al., 2014 ; Buss et al., 2015 ; Qiu et al., 2015 ) contaminants which depends on the feedstock and production conditions. The contaminant and nutrient content of the biochar feedstock has a significant impact on speciation and distribution of contaminants in biochar ( Adanez-Rubio et al., 2021 ). Freshly produced PAHs-contaminated biochar released PAHs in soils and the level of PAHs released decreased with aging ( Sigmund et al., 2017 ).…”