scholarly journals Comprehensive Evaluation of the Control Efficiency of Heavy-Metal Emissions during Two-Step Thermal Treatment of Sewage Sludge

ACS Omega ◽  
2020 ◽  
Vol 5 (38) ◽  
pp. 24467-24476 ◽  
Author(s):  
Yanlong Li ◽  
Zhenquan Fang ◽  
Wenchao Teng ◽  
Shengqiang Shen ◽  
Rundong Li
Keyword(s):  
Heavy Metal ◽  
Sewage Sludge ◽  
Thermal Treatment ◽  
Comprehensive Evaluation ◽  
Control Efficiency ◽  
Heavy Metal Emissions

Comprehensive Evaluation of Poly-Phosphate Release from Sewage Sludge with Thermal Treatment

2015 ◽  
Vol 768 ◽  
pp. 476-483
Author(s):  
Ming Yang Zhang ◽  
Jian Wei Du ◽  
Takahiro Kuba ◽  
Yong Wen
Keyword(s):  
Sewage Sludge ◽  
Thermal Treatment ◽  
Comprehensive Evaluation ◽  
Hot Spot ◽  
Indirect Evidence ◽  
Metal Cations ◽  
Heating Time ◽  
Phosphorus Recovery ◽  
Heating Process ◽  
The World

Phosphorus is a necessary nutrient element to all lives in the world. Distribution and phosphate rock reserves in the world disclose shortage crisis of phosphorus. Thus phosphorus recovery has been a research hot spot in the world. Mr.Ohtake’ group [1] recommended a new method to recover phosphorus from sewage sludge during heating process. It seems that nearly 90% of the poly-phosphate (poly-P) and 87% of total phosphate (T-P) can be released from cultivated sludge by heating at 70 °C for 1 hour. Meanwhile, released poly-P can precipitate with Ca in neutral condition without any pH adjustment. Sewage sludge was used in this research to identify its performance during thermal treatment. With the increase of temperature and heating time, release of poly-P and T-P increased obviously. However, poly-P would be hydrolyzed when temperature was higher than 80 °C. With addition of EDTA, release of poly-P increased nearly 100%. Migration of metal cations during thermal treatment can provide indirect evidence which kinds of metal cations would make impediment on poly-P release. A novel phenomenon was observed poly-P mixed with ortho-phosphate can precipitate with NH4+ and Mg2+ as struvite at pH 8.5.

scholarly journals Immobilization of selected heavy metals from fly ash from thermal treatment of municipal sewage sludge in hardening slurries

2018 ◽  
Vol 64 (3) ◽  
pp. 131-144 ◽  
Author(s):  
Łukasz Szarek ◽  
Paweł Falaciński ◽  
Małgorzata Wojtkowska
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Fly Ash ◽  
Sewage Sludge ◽  
Thermal Treatment ◽  
Sewage Treatment ◽  
Municipal Sewage ◽  
Municipal Sewage Sludge ◽  
Heavy Metal Immobilization ◽  
Key Issues

AbstractThe growing number of municipal sewage treatment plants in Poland raises the problem of managing more and more sludge. The thermal treatment of municipal sewage sludge (TTMSS), which significantly reduces the volume of waste, results in an increase in the concentration of heavy metals in the fly ashes – the final products of the process. The search for methods of utilization of fly ash from TTMSS resulted in attempts to use it in hardening slurries widely used in hydro-engineering. Due to the nature of the application of this material in the cut-off walls (exposure to groundwater flow) one of the key issues is the degree of heavy metal immobilization. The paper attempted to determine the degree of leaching of selected heavy metals from the hardened hardening slurry, composed of fly ash from TTMSS. For this purpose, the eluates were prepared from samples, after various periods of curing, using a dynamic short-term method called “Batch test”. The liquid used for leaching was: distilled water and 0.1 molar EDTA solution – to determine the amount of potentially mobile heavy metal forms. The results show the possibility of the safe usage of fly ash from TTMSS as an additive for hardening slurries.

scholarly journals Virtual flows of aquatic heavy metal emissions and associated risk in China

2019 ◽  
Vol 249 ◽  
pp. 109400 ◽  
Author(s):  
Wei Zhang ◽  
Miaomiao Liu ◽  
Klaus Hubacek ◽  
Kuishuang Feng ◽  
Wenjun Wu ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Heavy Metal Emissions

scholarly journals Environmental Safety Analysis of Red Mud-Based Cemented Backfill on Groundwater

2021 ◽  
Vol 18 (15) ◽  
pp. 8094
Author(s):  
Shuai Li ◽  
Yulin Zhang ◽  
Ru Feng ◽  
Haoxuan Yu ◽  
Jilong Pan ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Metal Ions ◽  
Red Mud ◽  
Heavy Metal Ions ◽  
Comprehensive Evaluation ◽  
Underground Mining ◽  
Fuzzy Comprehensive Evaluation ◽  
Low Grade ◽  
Cemented Backfill ◽  
Bleeding Water

As one of the main industrial solid wastes, there are a large number of free alkaloids, chemically bound alkaloids, fluoride, and heavy metal ions in Bayer process red mud (BRM), which are difficult to remove and easily pollute groundwater as a result of open storage. In order to realize the large-scale industrial application of BRM as a backfilling aggregate for underground mining and simultaneously avoid polluting groundwater, the material characteristics of BRM were analyzed through physical, mechanical, and chemical composition tests. The optimum cement–sand ratio and solid mass concentration of the backfilling were obtained based on several mixture proportion tests. According to the results of bleeding, soaking, and toxic leaching experiments, the fuzzy comprehensive evaluation method was used to evaluate the environmental impact of BRM on groundwater. The results show that chemically bound alkaloids that remained in BRM reacted with Ca2+ in PO 42.5 cement, slowed down the solidification speed, and reduced the early strength of red mud-based cemented backfill (RMCB). The hydration products in RMCB, such as AFT and C-S-H gel, had significant encapsulation, solidification, and precipitation inhibition effects on contaminants, which could reduce the contents of inorganic contaminants in soaking water by 26.8% to 93.8% and the leaching of toxic heavy metal ions by 57.1% to 73.3%. As shown by the results of the fuzzy comprehensive evaluation, the degree of pollution of the RMCB in bleeding water belonged to a medium grade Ⅲ, while that in the soaking water belonged to a low grade II. The bleeding water was diluted by 50–100 times to reach grade I after flowing into the water sump and could be totally recycled for drilling and backfilling, thus causing negligible effects on the groundwater environment.

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