Efficient conversion of sewage sludge into hydrochar by microwave-assisted hydrothermal carbonization

2021 ◽  
pp. 149874
Author(s):  
Yu-jie Wang ◽  
Yi Yu ◽  
Hua-jun Huang ◽  
Cheng-long Yu ◽  
Han-sun Fang ◽  
...  
Keyword(s):  
Sewage Sludge ◽  
Hydrothermal Carbonization ◽  
Microwave Assisted ◽  
Efficient Conversion

scholarly journals Sewage Sludge Treatment by Hydrothermal Carbonization: Feasibility Study for Sustainable Nutrient Recovery and Fuel Production

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2697
Author(s):  
Gabriel Gerner ◽  
Luca Meyer ◽  
Rahel Wanner ◽  
Thomas Keller ◽  
Rolf Krebs
Keyword(s):  
Liquid Phase ◽  
Sewage Sludge ◽  
Hydrothermal Carbonization ◽  
Economic Feasibility ◽  
Phosphorus Recovery ◽  
High Yield ◽  
Nutrient Recovery ◽  
Waste Biomass ◽  
Sludge Treatment ◽  
Sewage Sludge Treatment

Phosphorus recovery from waste biomass is becoming increasingly important, given that phosphorus is an exhaustible non-renewable resource. For the recovery of plant nutrients and production of climate-neutral fuel from wet waste streams, hydrothermal carbonization (HTC) has been suggested as a promising technology. In this study, digested sewage sludge (DSS) was used as waste material for phosphorus and nitrogen recovery. HTC was conducted at 200 °C for 4 h, followed by phosphorus stripping (PS) or leaching (PL) at room temperature. The results showed that for PS and PL around 84% and 71% of phosphorus, as well as 53% and 54% of nitrogen, respectively, could be recovered in the liquid phase (process water and/or extract). Heavy metals were mainly transferred to the hydrochar and only <1 ppm of Cd and 21–43 ppm of Zn were found to be in the liquid phase of the acid treatments. According to the economic feasibility calculation, the HTC-treatment per dry ton DSS with an industrial-scale plant would cost around 608 USD. Between 349–406 kg of sulfuric acid are required per dry ton DSS to achieve a high yield in phosphorus recovery, which causes additional costs of 96–118 USD. Compared to current sewage sludge treatment costs in Switzerland, which range between 669 USD and 1173 USD, HTC can be an economically feasible process for DSS treatment and nutrient recovery.

scholarly journals Valorization of tree leaves waste using microwave‐assisted hydrothermal carbonization process

GCB Bioenergy ◽  
2021 ◽  
Author(s):  
Kang Kang ◽  
Tianle Zhang ◽  
Guotao Sun ◽  
Mingqiang Zhu ◽  
Kankan Li ◽  
...  
Keyword(s):  
Hydrothermal Carbonization ◽  
Tree Leaves ◽  
Carbonization Process ◽  
Microwave Assisted

scholarly journals Intriguing Carbon Flake Formation during Microwave‐Assisted Hydrothermal Carbonization of Sodium Lignosulfonate (Global Challenges 8/2020)

2020 ◽  
Vol 4 (8) ◽  
pp. 2070081
Author(s):  
Giuseppe Melilli ◽  
Karin H. Adolfsson ◽  
Andrea Impagnatiello ◽  
Giancarlo Rizza ◽  
Minna Hakkarainen
Keyword(s):  
Hydrothermal Carbonization ◽  
Sodium Lignosulfonate ◽  
Microwave Assisted ◽  
Global Challenges

Hydrothermal carbonization characteristics of sewage sludge and lignocellulosic biomass. A comparative study

2019 ◽  
Vol 120 ◽  
pp. 166-175 ◽  
Author(s):  
Małgorzata Wilk ◽  
Aneta Magdziarz ◽  
Kandasamy Jayaraman ◽  
Monika Szymańska-Chargot ◽  
Iskender Gökalp
Keyword(s):  
Sewage Sludge ◽  
Comparative Study ◽  
Lignocellulosic Biomass ◽  
Hydrothermal Carbonization

scholarly journals Influence of Hydrothermal Carbonization on Composition, Formation and Elimination of Biphenyls, Dioxins and Furans in Sewage Sludge

Energies ◽  
2018 ◽  
Vol 11 (6) ◽  
pp. 1582 ◽  
Author(s):  
Heiner Brookman ◽  
Fabian Gievers ◽  
Volker Zelinski ◽  
Jan Ohlert ◽  
Achim Loewen
Keyword(s):  
Sewage Sludge ◽  
Organic Pollutants ◽  
Total Concentration ◽  
Hydrothermal Carbonization ◽  
Process Conditions ◽  
Limit Values ◽  
Composition Formation ◽  
Input Material ◽  
Dioxins And Furans ◽  
Toxicity Equivalent

In many areas of application, the influence of hydrothermal carbonization (HTC) on the composition of organic pollutants is still unexplored. In this study, sewage sludge (SS) was carbonized and the input as well as the hydrochar were examined for the organic pollutants: polychlorinated biphenyls (PCB), polychlorinated dibenzo-dioxins (PCDDs), and polychlorinated dibenzo-furans (PCDFs). The process temperatures of carbonization were 200 °C, 220 °C, and 240 °C and the holding time was 5 h for all tests. The total concentration of PCBs was relatively stable for all temperatures, whereas the toxicity equivalent (WHO-TEQ) at 200 °C and 220 °C increases compared to the input material. The strongest impact on toxicity was observed for PCDDs where concentrations were reduced for higher temperatures, whereas the toxicity increases by more than 16 times for temperatures of 240 °C. The concentrations and toxicity of PCDFs were reduced for all carbonization temperatures. In hydrochar from HTC at 240 °C, the limit values for the application of SS in German agriculture have been exceeded. The results indicate that the process conditions for HTC should be controlled also for SS with average contamination if the hydrochar is to be used as material, especially in agriculture.

scholarly journals Migration and transformation of heavy metals during the microwave-assisted thermal hydrolysis of sewage sludge

2021 ◽  
Author(s):  
Chunsheng Qiu ◽  
Jinxin Zheng ◽  
Chenchen Wang ◽  
Bingbing Wang ◽  
Nannan Liu ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Sewage Sludge ◽  
Ecological Risk ◽  
Risk Index ◽  
Oxygen Demand ◽  
Microwave Treatment ◽  
Potential Ecological Risk ◽  
Ammonium Nitrogen ◽  
Thermal Hydrolysis ◽  
Microwave Assisted

Abstract The migration, transformation and ecological risk of heavy metals (Cr, As, Ni, Cu, Zn, Cd and Pb) in the sewage sludge during the microwave-assisted thermal hydrolysis process were investigated under different temperatures (80 °C, 100 °C, 120 °C, 140 °C, and 160 °C). The potential relationship between the bio-availability of heavy metals and the variables of microwave treatment, including pH, ammonium-nitrogen, soluble chemical oxygen demand, pH, soluble protein, soluble polysaccharide and volatile solid, was also explored. The results showed that the migration of heavy metals between solid-liquid phase mainly depended on the temperature. The percentage of all heavy metals (except Cu) in mobile (acid-soluble/exchangeable and reducible) forms decreased after microwave-assisted thermal hydrolysis treatment. The solubilization of compounds with C = O and O-H accompanied with the generation of organic and inorganic metal halides were also observed in the treated sludge through fourier transform infrared spectroscopy analysis. NH4+-N showed the highest negative correlation to the bio-availability of most heavy metals (except Cu and Cr) with coefficients (absolute value) over 0.87 (P &lt; 0.05). VS showed a positive correlation to the bio-availability of most heavy metals (except Cu). The total potential ecological risk index (RI) decreased by 46.65% after microwave treatment at 160 °C.

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