Biogas Digester Hydraulic Retention Time Affects Oxygen Consumption Patterns and Greenhouse Gas Emissions after Application of Digestate to Soil

Abstract

Knowledge about environmental impacts associated with the application of anaerobic digestion residue to agricultural land is of interest owing to the rapid proliferation of biogas plants worldwide. However, virtually no information exists concerning how soil-emitted NO is affected by the feedstock hydraulic retention time (HRT) in the biogas digester. Here, the O planar optode technique was used to visualize soil O dynamics following the surface application of digestates of the codigestion of pig slurry and agro-industrial waste. We also used NO isotopomer analysis of soil-emitted NO to determine the NO production pathways, i.e., nitrification or denitrification. Two-dimensional images of soil O indicated that anoxic and hypoxic conditions developed at 2.0- and 1.5-cm soil depth for soil amended with the digestate produced with 15-d (PO15) and 30-d (PO30) retention time, respectively. Total NO emissions were significantly lower for PO15 than PO30 due to the greater expansion of the anoxic zone, which enhanced NO reduction via complete denitrification. However, cumulative CO emissions were not significantly different between PO15 and PO30 for the entire incubation period. During incubation, NO emissions came from both nitrification and denitrification in amended soils. Increasing the HRT of the biogas digester appears to induce significant NO emissions, but it is unlikely to affect the NO production pathways after application to soil.

Recent Advances in Chemical Sensors for Soil Analysis: A Review

“…Planar optodes have been used to investigate ammonium concentrations, diffusion, and transport in soil after fertilization [71,127,128]. The oxygen consumption and greenhouse gas emissions (mainly CO 2 ) in soils after were tested after amendment with organic fertilizers [129], and applications of digestate to soil [130] were previously monitored with PO sensors. An application of a SAW sensor functionalized with a polymeric coating (based on α,ω-dihydroxyalkyl lead(II)carboxylate complexes with 1,3-butadiene diepoxide as the co-monomer and 1,3,5-trihydroxybenzene as the reticulating agent) and a geophysical tool-ground penetrating RADAR (GPR)-to register sensor response, was reported to detect H 2 S in gas phase in a wireless configuration in soil and in real conditions (weather, temperature, and humidity) in [131].…”

Opportunities for Waste to Energy in the Milk Production Industry: Perspectives for the Circular Economy

“…Concerning the temperature regime, most investigations have been developed in the optimal temperature of the mesophilic regime (35 • C) [67,68]; see Table 3. It is important to mention that successful AD studies considering fruit and vegetable residues or swine slurry as substrates were found using temperature values lower than 20 • C [69,70]. In relation to CW, there are a few investigations, such as that developed by Yamashiro et al [71], that have studied two temperature regimes (mesophilic and thermophilic), although their objective was to make a digestate analysis to evaluate its final characteristics.…”

Intensification of biogas production using various technologies: A review

“…Methane and carbon dioxide, which are the main components of biogas, add to the greenhouse gas effect if released from landfills, WWTPs or farms. This is the reason why it is essential that biogas be obtained under controlled conditions and used to generate thermal energy and electricity . This article contains a review of literature published recently (Figure S1), and an overview of various technologies employed in biogas production.…”

“…This is the reason why it is essential that biogas be obtained under controlled conditions and used to generate thermal energy and electricity. 30,31 This article contains a review of literature published recently (Figure S1), and an overview of various technologies employed in biogas production. This study describes both biological and physicochemical factors that can influence the process of biogas production.…”