Feedwater pH affects phosphorus transformation during hydrothermal carbonization of sewage sludge

2017 ◽  
Vol 245 ◽  
pp. 182-187 ◽  
Author(s):  
Tao Wang ◽  
Yunbo Zhai ◽  
Yun Zhu ◽  
Chuan Peng ◽  
Tengfei Wang ◽  
...  
Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2697
Author(s):  
Gabriel Gerner ◽  
Luca Meyer ◽  
Rahel Wanner ◽  
Thomas Keller ◽  
Rolf Krebs

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.


2019 ◽  
Vol 120 ◽  
pp. 166-175 ◽  
Author(s):  
Małgorzata Wilk ◽  
Aneta Magdziarz ◽  
Kandasamy Jayaraman ◽  
Monika Szymańska-Chargot ◽  
Iskender Gökalp

Energies ◽  
2018 ◽  
Vol 11 (6) ◽  
pp. 1582 ◽  
Author(s):  
Heiner Brookman ◽  
Fabian Gievers ◽  
Volker Zelinski ◽  
Jan Ohlert ◽  
Achim Loewen

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.


2018 ◽  
Vol 78 (4) ◽  
pp. 947-956 ◽  
Author(s):  
Jia Wei ◽  
Yitao Liu ◽  
Jun Li ◽  
Hui Yu ◽  
Yongzhen Peng

Abstract In this work, a microporous municipal sewage sludge-derived hydrochar (MSSH) with relatively high surface area and abundant surface organic functional groups was produced through hydrothermal carbonization. Based on the adsorption results over a wide range of conditions, the prepared MSSH was suggested as a promising adsorbent for CV because of its high and efficient adsorption capability. The experimental data were fitted to several kinetic models. Based on calculated respective parameters such as rate constants, equilibrium adsorption capacities and correlation coefficients, the pseudo second-order model proved the best in describing the adsorption behavior of MSSH. Through kinetics, thermodynamic modeling studies and material characterization, a plausible adsorption process was discussed under the conditions used in this study. It can be confirmed that the adsorption of CV onto MSSH is via both physical interactions (electrostatic interaction and Van der Waals' force) and chemical interactions (formation of H-bonding).


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