Assessment and prediction of carbon dioxide emissions from soils enriched with biochar produced from sewage sludge

MINIATURA 7

Funding Organization: National Science Centre

Project title: Assessment and prediction of carbon dioxide emissions from soils enriched with biochar produced from sewage sludge

Agreement number: DEC-2023/07/X/ST10/00655

Project implementation period: 05.10.2023 - 04.10.2024

Principal Investigator: dr Justyna Kujawska

Project value: 28 600,00 PLN

Funds granted for Lublin University of Technology: 28 600,00 PLN

Abstract: Climate change is one of the most significant challenges of the modern world. In the context of mitigating climate change, implementing technology to remove CO2 from the atmosphere is a key task. Considering the enormous potential of soils for carbon sequestration, it seems necessary to focus on increasing their role in preventing climate change. In recent years, increasing attention has been paid to research on the sequestration of atmospheric CO2 captured in the process of photosynthesis in biomass, and then transforming carbon into a more stable form through thermal processing, producing what is known as biochar. Introducing stable carbon into agricultural soils in the form of biochar has been recognized as an effective tool for enhancing soil carbon sequestration to mitigate climate change. Most research in this area concerns biochars from plant biomass. In the presented project, we propose the use of biochars from sewage sludge for carbon sequestration in soil and limiting carbon dioxide emissions. The amount of generated wastewater and resulting sewage sludge is constantly increasing with population and industry development. Therefore, beneficial ways of disposing of sewage sludge are being sought. One of them may be transforming sewage sludge into biochars.
We hypothesize that i) biochars will reduce carbon dioxide emissions from agricultural soils ii) the potential of biochar to reduce carbon dioxide emissions depends on the properties of the soil and biochar, and iii) biochars will improve the efficiency of nitrogen and other nutrient uptake by plants.
The main goal of the planned research will be to assess the impact of soil properties and external factors on CO2 emissions from soil fertilized with biochar. The specific objectives will be i) to assess carbon dioxide emissions from agricultural soils (alfisols and chernozems) with the addition of sewage sludge biochars (in doses of 0, 5, 10, 20, 40 t/ha), produced under various pyrolysis conditions, under controlled laboratory conditions ii) to determine the relationships caused by the addition of biochar to changes in carbon dioxide emissions and the properties of biochar (pH, C content, N content, C:N ratio, nutrient content: Mg, K, P, nitrogen forms) and soil properties (pH, C content, N content, C:N ratio, nutrient content: Mg, K, P, nitrogen forms), and iii) to determine the quantitative impact of the biochar dose on the content of organic carbon, nutrients in the soil (nitrogen, phosphorus, potassium concentration).
The most innovative element of the project will be the creation of a neural network model that will predict carbon dioxide emissions with a minimum amount of input data. Modeling will be carried out using the so-called 'black box' model, which involves finding the best fit of input data to a given output, which will be carbon dioxide emissions. The input data will be the physico-chemical and chemical properties of soils with the addition of biochars. Simulations will be performed using artificial neural networks and conducted using Statistica Neural Networks software. As a result of the modeling, it will be possible to predict carbon dioxide emissions from soils, given certain properties of soil mixtures. Research conducted as part of the project implementation will help determine the optimal doses of biochar that can be introduced into soils with specific properties to limit carbon dioxide emissions from these soils. Sewage sludge will be transformed into biochars in a pyrolytic reactor at temperatures: 400°C, 500°C, 600°C, 800°C. Pot soil studies will be conducted in a phytotron, allowing control of moisture, temperature, and lighting. Studies of the composition of biochars, soils, and their mixtures will be carried out using a Shimadzu TOC-5050A organic carbon analyzer, an automatic Kjeldahl method total nitrogen analyzer - KjeltecTM 8200 Foss Tecator system (Foss, Hoganas, Sweden), for metal determination an Agilent 8900 ICP-MS (ICP-QQQ) spectrometer with a system for speciation analysis using HPLC and GS. CO2 emission measurements will be made using a chamber method with a CO2 probe (CO2 probe GMP 343, Vaisala Oy, Helsinki, Finland). These innovative studies on the use of sewage sludge biochars in reducing carbon dioxide emissions from agricultural soils will contribute to the fight against climate change. Additionally, the use of biochar in Poland is a new topic, and biochar and its applications are not yet included in national legislation. A tangible and documented effect of the action taken will be the publication of results in significant journals in the disciplines of environmental engineering, mining, and energy. Additionally, it is assumed that the effects of scientific activity will be disseminated at scientific conferences, among people interested in climate change issues.