Feasibility of Biochar Derived from Sewage Sludge to Promote Sustainable Agriculture and Mitigate GHG Emissions—A Review

Abstract

Sewage sludge (SS) has been connected to a variety of global environmental problems. Assessing the risk of various disposal techniques can be quite useful in recommending appropriate management. The preparation of sewage sludge biochar (SSB) and its impacts on soil characteristics, plant health, nutrient leaching, and greenhouse gas emissions (GHGs) are critically reviewed in this study. Comparing the features of SSB obtained at various pyrolysis temperatures revealed changes in its elemental content. Lower hydrogen/carbon ratios in SSB generated at higher pyrolysis temperatures point to the existence of more aromatic carbon molecules. Additionally, the preparation of SSB has an increased ash content, a lower yield, and a higher surface area as a result of the rise in pyrolysis temperature. The worldwide potential of SS output and CO2-equivalent emissions in 2050 were predicted as factors of global population and common disposal management in order to create a futuristic strategy and cope with the quantity of abundant global SS. According to estimations, the worldwide SS output and associated CO2-eq emissions were around 115 million tons dry solid (Mt DS) and 14,139 teragrams (Tg), respectively, in 2020. This quantity will rise to about 138 Mt DS sewage sludge and 16985 Tg CO2-eq emissions in 2050, a 20% increase. In this regard, developing and populous countries may support economic growth by utilizing low-cost methods for producing biochar and employing it in local agriculture. To completely comprehend the benefits and drawbacks of SSB as a soil supplement, further study on long-term field applications of SSB is required.

Production strategies and potential repercussion of sewage sludge biochar as a futuristic paradigm toward environmental beneficiation: A comprehensive review

“…Based on its holistic review, it is crucial to consider the socioeconomic aspects of its production and consumption (Arazo et al, 2021). Several researchers (Pandey et al, 2021;Kishor et al, 2021;Xue et al, 2021) 384.31 (Shirani et al, 2020) expensive than manufacturing costs, which include labor, storage, utility costs, and other costs (which range from 51 to 5668 US dollars per ton) (Ghorbani et al, 2022). According to the study reported by , an estimated US$195,000 is spent each year on the shipping, treatment, and disposal of SSB.…”

“…given the benefits of applying SSB to soil, which include higher yields and decreased GHG emissions (Ghorbani et al, 2022). The research of Gievers et al (2021) showed that using biochar properly and pyrolyzing digested sewage sludge can be a green alternative to both sequestering carbon and breaking the nutrient cycle.…”

Deashed Wheat-Straw Biochar as a Potential Superabsorbent for Pesticides

“…in the form of oxides, phosphates, carbonates and silicates [ 18 ]. Such properties facilitate its use in agriculture as a liming agent and an amendment abundant in some macro- and micronutrients, especially in the case of sludge and animal-derived biochars [ 20 , 21 , 22 , 23 ]. In contrast, high-temperature (>500 °C) plant-derived biochars are more commonly used to mitigate soil contamination via immobilization of heavy metals and organic pollutants [ 24 , 25 , 26 ].…”

“Green” nZVI-Biochar as Fenton Catalyst: Perspective of Closing-the-Loop in Wastewater Treatment

“…In Japan, 70% of SS is managed by incineration. More than half of the SS in South Korea is dumped into the sea [ 6 ]. Worldwide sludge production will continue to grow due to increasing urbanization and industrialization.…”

“…This method has many advantages such as reducing sludge volume by 80%, the removal of pathogenic agents and hazardous compounds from SS, metals being immobilized in a solid residue, thus reducing their leaching, and organic and inorganic fractions being immobilized in a stabilized form of pyrolytic residues (biochar) [ 10 ]. There are many benefits of biochar (BC) production: energy production, sustainable waste recycling, carbon sequestration, improvement in soil quality, plant development, and mitigating greenhouse gas (GHG) emissions [ 6 , 11 , 12 ]. Many studies have proven that the pyrolysis of sewage sludge to biochar can be more effective than the application of raw sewage sludge in reducing the environmental risks of the potentially toxic metals involved in land application [ 13 , 14 ].…”