Hierarchically porous biochar preparation and simultaneous nutrient recovery from sewage sludge via three steps of alkali-activated pyrolysis, water leaching and acid leaching

2022 ◽  
Vol 176 ◽  
pp. 105953
Author(s):  
Jingjing Qiu ◽  
Huijie Hou ◽  
Sha Liang ◽  
Liang Yang ◽  
Quan Gan ◽  
...  
Keyword(s):  
Sewage Sludge ◽  
Acid Leaching ◽  
Nutrient Recovery ◽  
Water Leaching ◽  
Hierarchically Porous ◽  
Alkali Activated

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 Recovery of Zinc and Silver from Zinc Acid-Leaching Residues with Reduction of Their Environmental Impact Using a Novel Water Leaching-Flotation Process

Minerals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 586
Author(s):  
Yunpeng Du ◽  
Xiong Tong ◽  
Xian Xie ◽  
Wenjie Zhang ◽  
Hanxu Yang ◽  
...  
Keyword(s):  
Hazardous Waste ◽  
Acid Leaching ◽  
Copper Recovery ◽  
Water Leaching ◽  
Flotation Process ◽  
Metal Levels ◽  
Valuable Metals ◽  
Leaching Experiments ◽  
Zinc Hydrometallurgy ◽  
Poor Stability

Zinc-leaching residue (ZLR) is a strongly acidic hazardous waste; it has poor stability, high heavy metal levels, and releases toxic elements into the environment. ZLR has potential as a valuable resource, because it contains elevated levels of zinc and silver. In this paper, the recovery of zinc (Zn) and silver (Ag) from ZLR wastes from zinc hydrometallurgy workshops using water leaching followed by flotation was studied. During water leaching experiments, the zinc and copper recovery rates were 38% and 61%, respectively. Thereafter, various flotation testing parameters were optimized and included grinding time, reagent dosages, pulp density, flotation time, and type of adjuster. Experimental results demonstrated this flotation method successfully recycled Ag and Zn. A froth product containing more than 9256.41 g/t Ag and 12.26% Zn was produced from the ZLR with approximately 80.32% Ag and 42.88% Zn recoveries. The toxicity characteristic leaching procedure (TCLP) results indicated the water-leaching flotation process not only recycled valuable metals such as zinc and silver in zinc-containing hazardous wastes but lowered the hazardous waste levels to those of general wastes and recycled wastes in an efficient, economical, and environmentally friendly way.

Recovery Technology of Zinc from Hydrometallurgical Zinc Residues

2011 ◽  
Vol 396-398 ◽  
pp. 620-623
Author(s):  
Ya Li Zhang ◽  
Xian Jin Yu ◽  
Xiao Na Guo ◽  
Xiao Bin Li
Keyword(s):  
Acid Leaching ◽  
Optimum Conditions ◽  
Water Leaching ◽  
Zn Content

In this work, it was aimed to select and propose a feasible as well as an applicable method, or series of methods for the extraction of zinc. After determination of the components of the residue, water leaching, acid leaching and roasting-leaching were performed to reclaim Zn. Roasting-leaching was found to be effectively for Zn extraction by controlling acid mass, roasting duration and temperature as parameters. At the optimum conditions, 0.7 times the amount of H2SO4 at 250 °C for 150 min in roasting, 82.05% of initial Zn content was extracted.

Investigations on the Mechanism of Acid Leaching of Alkali-activated Ilmenite Concentrate and Titanium-rich Slag

2011 ◽  
pp. 285-290
Author(s):  
Xu Qian ◽  
Fu yajun ◽  
Sun Lin ◽  
Jin Jianfeng ◽  
Du jihong
Keyword(s):  
Acid Leaching ◽  
Ilmenite Concentrate ◽  
Alkali Activated

scholarly journals Cobalt Based Catalysts on Alkali-Activated Zeolite Foams for N2O Decomposition

Catalysts ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1398
Author(s):  
Zdeněk Tišler ◽  
Anna Klegová ◽  
Eliška Svobodová ◽  
Jan Šafář ◽  
Kateřina Strejcová ◽  
...  
Keyword(s):  
Ion Exchange ◽  
Alkali Metals ◽  
Catalyst Activity ◽  
Acid Leaching ◽  
N2o Decomposition ◽  
Cobalt Catalysts ◽  
Alkali Activation ◽  
Incipient Wetness Impregnation ◽  
Exchange Method ◽  
Alkali Activated

In this work, we studied the effect of alkali-activated zeolite foams modifications on properties and catalytic activity of cobalt phases in the process of catalytic decomposition of N2O. The zeolite foam supports were prepared by alkali activation of natural zeolite followed by acid leaching and ion exchange. The cobalt catalysts were synthesised by a different deposition technique (direct ion exchange (DIE) and incipient wetness impregnation (IWI) method of cobalt on zeolite foams. For comparison, catalysts on selected supports were prepared and the properties of all were compared in catalytic tests in the pellet form and as crushed catalysts to determine the effect of internal diffusion. The catalysts and supports were in detail characterized by a variety of techniques. The catalyst activity strongly depended on the structure of support and synthesis procedure of a cobalt catalyst. Ion exchange method provided active phase with higher surface areas and sites with better reducibility, both of these factors contributed to higher N2O conversions of more than 80% at 450 °C. A large influence can also be attributed to the presence of alkali metals, in particular, potassium, which resulted in a modification of electronic and acid base properties of the cobalt oxide phase on the catalyst surface. The promotional effect of potassium is better reducibility of cobalt species.

scholarly journals An Improved Evaluation Strategy for Ash Analysis Using Scanning Electron Microscope Automated Mineralogy

Minerals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 484 ◽  
Author(s):  
Andrea C. Guhl ◽  
Valentin-G. Greb ◽  
Bernhard Schulz ◽  
Martin Bertau
Keyword(s):  
Sewage Sludge ◽  
Acid Leaching ◽  
Target Material ◽  
Analytical Techniques ◽  
Data Interpretation ◽  
Target Component ◽  
Sewage Sludge Ash ◽  
Phosphate Recovery ◽  
Automated Mineralogy ◽  
Sludge Ash

Sewage slush ashes are materials composed of polyphase particles. Ashes are fine-grained with many amorphous components, and analytical techniques such as X-ray diffractometry cannot recover all the properties. For sewage sludge ash, treatment often focuses on phosphate recovery. Automated mineralogy techniques were applied in order to study phosphate associations and their behavior towards chemical processes. This work shows the distribution of phosphate content in sewage sludge ash and identifies the main recovered phosphate phases in acid leaching. Data interpretation was focused on the target material, phosphate. The approach documents spectra labelling with respect to one target component, phosphorus. This is a tool for assessing sewage sludge ashes towards their phosphate recovery potential and highlights issues processing needs to address.

Tendencies and Overview on the Nutrient Recovery from Sewage Sludge in Germany

2008 ◽  
Vol 3 (1) ◽  
Author(s):  
Alexander Weidelener ◽  
Demet Antakyalı ◽  
Jörg Krampe
Keyword(s):  
Land Use ◽  
Sewage Sludge ◽  
Current Situation ◽  
Raw Material ◽  
Nutrient Recovery ◽  
Research Institutions ◽  
Material Recovery ◽  
Conventional Production ◽  
Fertiliser Use

The critics against the land use of sewage sludge in Germany lead the research institutions to investigate methods for nutrient recovery. Current research proved that the nutrients such as nitrogen or phosphorus can be recovered. Though, the costs still must be reduced to compete with the conventional production using fresh raw material. Recovery products are not listed in current legislations concerning fertiliser use, therefore the land use of the recovered products require some legislative replenishments. The paper portrays the current situation concerning the above discussions with an overview on the actual recovery technologies

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