Effect of Hydraulic Retention Time on the Sulfate Reduction Process and Metal Precipitates Characteristics

2022 ◽  
pp. 75-98
Author(s):  
Denys Kristalia Villa Gómez
2013 ◽  
Vol 825 ◽  
pp. 392-395 ◽  
Author(s):  
Robert Klein ◽  
Michael Schlömann ◽  
Yun Zeng ◽  
Bernd Wacker ◽  
Franz Glombitza ◽  
...  

Treatment of acidic Fe (II)- and sulfate-rich mine waters represents a major problem in many areas of the world. Therefore, a process was developed which utilises naturally occurring sulfate-reducing microorganisms for the elimination of sulfate and of part of the acidity from the acidic mine water. In order to improve the performance of this biological sulfate reduction process an in-depth analysis of the microbial diversity and activity in dependence of the hydraulic retention time (HRT) and other process parameters used to run the bioreactors was undertaken. This comparison demonstrated a positive correlation between shorter HRT and increasing sulfate reduction rates. The improvement in performance with decreasing HRT was paralleled by an increase of the total enzymatic activity (measured as hydrolase activity) of the microbial community and of the biomass (measured as protein concentration) in the bioreactors. A partial taxonomic identification of the microbial community in the bioreactors was achieved via nucleotide sequence analysis of a clone library of PCR-amplified 16S rRNA gene fragments prepared from a sample of the microbial biofilm in the bioreactor. Additionally, the genetic fingerprint technique T-RFLP was used to assess temporal changes of the microbial community in the biofilm within the reactor.


2013 ◽  
Vol 67 (2) ◽  
pp. 311-318 ◽  
Author(s):  
Madawala Liyanage Duminda Jayaranjan ◽  
Ajit P. Annachhatre

Investigations were undertaken to utilize flue gas desulfurization (FGD) gypsum for the treatment of leachate from the coal ash (CA) dump sites. Bench-scale investigations consisted of three main steps namely hydrogen sulfide (H2S) production by sulfate reducing bacteria (SRB) using sulfate from solubilized FGD gypsum as the electron acceptor, followed by leaching of heavy metals (HMs) from coal bottom ash (CBA) and subsequent precipitation of HMs using biologically produced sulfide. Leaching tests of CBA carried out at acidic pH revealed the existence of several HMs such as Cd, Cr, Hg, Pb, Mn, Cu, Ni and Zn. Molasses was used as the electron donor for the biological sulfate reduction (BSR) process which produced sulfide rich effluent with concentration up to 150 mg/L. Sulfide rich effluent from the sulfate reduction process was used to precipitate HMs as metal sulfides from CBA leachate. HM removal in the range from 40 to 100% was obtained through sulfide precipitation.


Chemosphere ◽  
2019 ◽  
Vol 236 ◽  
pp. 124246 ◽  
Author(s):  
Shahrokh Shahsavari ◽  
Rajesh Seth ◽  
Subba Rao Chaganti ◽  
Nihar Biswas

2007 ◽  
Vol 20-21 ◽  
pp. 197-200 ◽  
Author(s):  
Anke Wolthoorn ◽  
Simon Kuitert ◽  
Henk Dijkman ◽  
Jacco L. Huisman

In a bench scale trial biological sulfate reduction was applied to convert anglesite (PbSO4) to galena (PbS). Anglesite is a main constituent of waste fractions such as the residue from an indirect leaching process or in lead paste from spent car batteries. The goal of this study was to develop a technology to decrease the lead (Pb) emissions by converting PbSO4 from a waste fraction into PbS, which can be recovered from the waste fraction using a flotation process or an electrochemical process. The conversion of anglesite to galena is based on the biological sulfate reduction process and a metal precipitation process. First sulfate is biologically reduced to sulfide. Secondly, the Pb2+ from the PbSO4 reacts chemically with the sulfide resulting from the first reaction. A bench-scale reactor was started up using sulfate- and sulfur-containing influent. The reactor was seeded with biocatalyst from several full-scale reactors. Anglesite-containing residue was added batch-wise when the formation of sulfide started. The residue contained mainly PbSO4 (51.7%), sulfate (SO4 2-, 19.9%) and elemental sulfur (S0, 15.1%). Galena precipitates in the bioreactor due to the near-neutral pH at which sulfate reduction is carried out. During the experiment a surplus of sulfide relative to Pb was maintained to prevent the formation of PbCO3 and the accompanying pH decrease that would unavoidable result in the inhibition of the biocatalyst. Both sulfate and sulfur present in the residue were biologically reduced. The formation of PbS was confirmed by the increased Pb:O ratio of the sludge (1:0.03) relative to the Pb:O ratio of the residue (1:0.3). A potential large-scale application is proposed.


2021 ◽  
Author(s):  
Guoqing Cheng ◽  
Huili Ding ◽  
Guanglin Chen ◽  
Hongjie Shi ◽  
Xu Zhang ◽  
...  

Abstract Sulfate-containing wastewater has a serious threat to the environment and human health. Microbial technology has great potential for the treatment of sulfate-containing wastewater. It was found that nano-photocatalysts could be used as extracellular electron donors to promote the growth and metabolic activity of non-photosynthetic microorganisms. However, nano-photocatalysts could also induce oxidative stress and damage cells. In this paper, the mechanism and regulation strategy of cadmium sulfide nanoparticles(CdS NPs)on the growth of sulfate reducing bacteria and the sulfate reduction process were investigated. The results shows that the sulfate reduction efficiency could be increased by 6.43% through CdS NPs under light conditions. However, the growth of C09 was seriously inhibited by 55.00% due to the oxidative stress induced by CdS NPs on cells. The biomass and sulfate reduction efficiency could be enhanced by 6.84% and 5.85%, respectively, through external addition of humic acid (HA). At the same time, the mechanism of the CdS NPs strengthening the sulfate reduction process by sulfate bacteria was also studied. Which can provide important theoretical guidance and technical support for the development of microbial technology combined with extracellular electron transfer (EET) for the treatment of sulfate-containing wastewater.


2010 ◽  
Vol 113-116 ◽  
pp. 536-539
Author(s):  
Wei Li ◽  
Xiao Liang ◽  
Jian Guo Lin

In order to treat wastewater rich in sulfate and organic carbon, an anaerobic attached-growth bioreactor was set up. It was the pretreatment of desulfurization-denitrification process. At hydraulic retention time of 128h-6.2h, sulfate removal rate and sulfide generating rate took on initial increasing and subsequent decreasing. At hydraulic retention time of 7.7h-10.2h, the removals of sulfate and organic carbon, sulfide generating rate reached 95.79%, 80% and 58.82%, respectively. The results showed that the suitable hydraulic retention time in sulfate reduction stage for the pretreatment of desulfurization-denitrification process was 7.7h-10.2h.


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