scholarly journals Synthesis of Poly-Alumino-Ferric Sulphate Coagulant from Acid Mine Drainage by Precipitation

Metals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1166 ◽  
Author(s):  
Brian Mwewa ◽  
Srećko Stopić ◽  
Sehliselo Ndlovu ◽  
Geoffrey S. Simate ◽  
Buhle Xakalashe ◽  
...  
Keyword(s):  
Acid Mine Drainage ◽  
Mine Drainage ◽  
Environmental Concern ◽  
Oxygen Demand ◽  
Ferric Sulphate ◽  
Brewery Wastewater ◽  
Metal Mining ◽  
Acid Mine ◽  
Sludge Disposal ◽  
Co Precipitation

The wastes generated from both operational and abandoned coal and metal mining are an environmental concern. These wastes, including acid mine drainage (AMD), are treated to abate the devastating effects they have on the environment before disposal. However, AMD contains valuable resources that can be recovered to subsidize treatment costs. Two of the major constituents of coal AMD are iron and aluminium, which can be recovered and engineered to function as coagulants. This work examines the potential of producing a poly-alumino-ferric sulphate (AMD-PAFS) coagulant from coal acidic drainage solutions. The co-precipitation of iron and aluminium is conducted at pH values of 5.0, 6.0 and 7.0 using sodium hydroxide in order to evaluate the recovery of iron and aluminium as hydroxide precipitates while minimizing the co-precipitation of the other heavy metals. The precipitation at pH 5.0 yields iron and aluminium recovery of 99.9 and 94.7%, respectively. An increase in the pH from 5.0 to 7.0 increases the recovery of aluminium to 99.1%, while the recovery of iron remains the same. The precipitate formed at pH 5.0 is used to produce a coagulant consisting of 89.5% and 10.0% iron and aluminium, respectively. The production of the coagulant is carried out by dissolving the precipitate in 5.0% (w/w) sulphuric acid. Subsequently, the treatment of the brewery wastewater shows that the AMD-PAFS coagulant is as efficient as the conventional poly ferric sulphate (PFS) coagulant. The turbidity removal is 91.9 and 87.8%, while the chemical oxygen demand (COD) removal is 56.0 and 64.0% for AMD-PAFS and PFS coagulants, respectively. The developed process, which can easily be incorporated into existing AMD treatment plants, not only reduces the sludge disposal problems but also creates revenue from waste.

scholarly journals Induction of a geochemical barrier for As, Fe and S immobilization in a sulfide substrate

2012 ◽  
Vol 36 (2) ◽  
pp. 671-679 ◽  
Author(s):  
Igor Rodrigues de Assis ◽  
Luiz Eduardo Dias ◽  
Emerson Silva Ribeiro Jr ◽  
Walter Antônio Pereira Abrahão ◽  
Jaime Wilson Vargas de Mello ◽  
...  
Keyword(s):  
Acid Mine Drainage ◽  
Mine Drainage ◽  
Environmental Concern ◽  
Experimental Period ◽  
Control Treatment ◽  
Geochemical Barrier ◽  
Acid Mine ◽  
Element Mobilization ◽  
Co Precipitation ◽  
The Impact

Acid mine drainage (AMD) is an environmental concern due to the risk of element mobilization, including toxic elements, and inclusion in the food chain. In this study, three cover layers were tested to minimize As, Fe and S mobilization from a substrate from former gold mining, containing pyrite and arsenopyrite. For this purpose, different layers (capillary break, sealant and cover layer) above the substrate and the induction of a geochemical barrier (GB) were used to provide suitable conditions for adsorption and co-precipitation of the mobilized As. Thirteen treatments were established to evaluate the leaching of As, Fe and S from a substrate in lysimeters. The pH, As, Fe, S, Na, and K concentrations and total volume of the leachates were determined. Mineralogical analyses were realized in the substrate at the end of the experimental period. Lowest amounts of As, Fe and S (average values of 5.47, 48.59 and 132.89 g/lysimeter) were leached in the treatments that received Na and K to induce GB formation. Mineralogical analyses indicated jarosite formation in the control treatment and in treatments that received Na and K salts. However, the jarosite amounts in these treatments were higher than in the control, suggesting that these salts accelerated the GB formation. High amounts of As, Fe and S (average values of 11.7, 103.94 and 201.13 g/lysimeter) were observed in the leachate from treatments without capillary break layer. The formation of geochemical barrier and the use of different layers over the sulfide substrate proved to be efficient techniques to decrease As, Fe and S mobilization and mitigate the impact of acid mine drainage.

Bioremediation of acid mine drainage coupled with domestic wastewater treatment

2012 ◽  
Vol 66 (11) ◽  
pp. 2425-2431 ◽  
Author(s):  
Irene Sánchez-Andrea ◽  
David Triana ◽  
Jose L. Sanz
Keyword(s):  
Carbon Source ◽  
Acid Mine Drainage ◽  
Mine Drainage ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Environmental Concern ◽  
Oxygen Demand ◽  
Domestic Wastewater ◽  
Elevated Concentration ◽  
Dissolved Metals ◽  
Acid Mine

Acid mine drainage (AMD) – characterized by high acidity and elevated sulfate and metal concentrations – represents a big environmental concern. Biological sulfate reduction has become an alternative to the classical physicochemical methods. In this study, domestic wastewater (DW) was tested as a cost-effective carbon-source for the remediation of AMD. Sediments from Tinto River, an extreme acidic environment with an elevated concentration of metals, were used as inoculum. Three anaerobic bioreactors with different microbial supports were fed with a 1:10 (v:v) mixture of synthetic AMD:DW. Around 50% of the organic matter present in the DW co-precipitated with the metals from the AMD previous to feeding the reactor. Therefore, the reactors had to be supplemented with an extra carbon-source (acetate) to achieve higher S elimination. Elevated removal efficiencies of chemical oxygen demand (COD) (>88%), sulfate (>75%), Fe (>85%) and other dissolved metals (>99% except for Mn) were achieved. Bacterial communities were examined through denaturing gradient gel electrophoresis and scanning electron microscopy. Higher biodiversity was found in the bioreactors compared with that of the inoculum. Dominant species belong to two metabolic groups: fermentative (Clostridium spp., Delftia spp., Paludibacter spp. and Pelotomaculum spp.) and sulfate-reducing bacteria (Desulfomonile spp., Desulfovibrio spp., Desulfosporosinus spp. and Desulfotomaculum spp.).

Mechanisms and Remediation Technologies of Sulfate Removal from Acid Mine Drainage

2012 ◽  
Vol 610-613 ◽  
pp. 3252-3256
Author(s):  
Mei Qin Chen ◽  
Feng Ji Wu
Keyword(s):  
Heavy Metals ◽  
Acid Mine Drainage ◽  
Mine Drainage ◽  
Metal Corrosion ◽  
Sulfate Ion ◽  
High Concentration ◽  
Biological Reduction ◽  
Acid Mine ◽  
Sulfate Removal ◽  
Co Precipitation

Acid mine drainage (AMD) has properties of extreme acidification, quantities of sulfate and elevated levels of soluble heavy metals. It was a widespread environmental problem that caused adverse effects to the qualities of ground water and surface water. In the past decades, most of investigations were focused on the heavy metals as their toxicities for human and animals. As another main constitution of AMD, sulfate ion is nontoxic, yet high concentration of sulfate ion can cause many problems such as soil acidification, metal corrosion and health problems. More attention should be paid on the sulfate ion when people focus on the AMD. In the paper, sulfate removal mechanisms include adsorption, precipitation, co-precipitation and biological reduction were analyzed and summarized. Meanwhile, the remediation technologies, especially the applications of them in China were also presented and discussed.

scholarly journals Bench-scale comparison of conventional and high rate clarification treatment processes for acid mine drainage

2015 ◽  
Vol 50 (3) ◽  
pp. 279-286 ◽  
Author(s):  
Allison L. Mackie ◽  
Margaret E. Walsh
Keyword(s):  
Acid Mine Drainage ◽  
Mine Drainage ◽  
High Rate ◽  
Volume Index ◽  
Dissolved Metals ◽  
Metal Mining ◽  
Acid Mine ◽  
High Concentrations ◽  
Solids Content ◽  
Federal Guidelines

Acid mine drainage (AMD) is characterized as having low pH and high concentrations of sulfate and dissolved metals. This study compared treated water quality and sludge properties of three process technologies for AMD: conventional sedimentation, high density sludge (HDS), and ballasted flocculation. All three processes were found to be capable of removing regulated metals to concentrations below current Canadian discharge guidelines. However, ballasted flocculation was the only technology found to be able to meet the more stringent federal guidelines proposed for future implementation under the Fisheries' Act's Metal Mining Effluent Regulations. Specifically, arsenic and zinc concentrations in AMD treated by the conventional and HDS processes were above proposed future guidelines of 0.10 and 0.25 mg/L, respectively, while lead, copper, and nickel all met respective guidelines. Concentrations of all regulated contaminants were below proposed guidelines when treated by ballasted flocculation. The HDS process was found to produce a significantly more concentrated sludge than conventional sedimentation (i.e., higher solids content (19 ± 1% versus 7 ± 4% wet solids) and lower sludge volume index (SVI; 8.4 ± 0.8 versus 230 ± 20 mL/g)).

scholarly journals Study of Precipitating Methods for Elimination of Heavy Metals from Acid Mine Drainage

2012 ◽  
Vol 11 (2) ◽  
pp. 133-138 ◽  
Author(s):  
Alena Luptáková ◽  
Stefano Ubaldini ◽  
Eva Mačingová ◽  
Ingrida Kotuličová
Keyword(s):  
Heavy Metals ◽  
Acid Mine Drainage ◽  
Chemical Method ◽  
Mine Drainage ◽  
Selective Precipitation ◽  
Acid Mine ◽  
Successive Repetition ◽  
Synthetic Solution ◽  
Zinc Mine ◽  
Co Precipitation

Abstract The submitted paper deals with the study of combination of chemical and biological-chemical methods for the heavy metals elimination from the acid mine drainage. The experiments were carried out at the laboratory scale using a synthetic solution with similar properties to the real sample of acid mine drainage, originating from the zinc mine located in Tùnel Kingsmill outflow of the Rio Yaulì (district of Yauli - Perù). The successive repetition of the metal precipitations as hydroxides (chemical method) and sulphides (biological-chemical method) at the various acid mine drainage pH was the basis of the examined processes. For the hydrogen sulphide production the sulphate-reducing bacteria of genus Desulfovibrio were used. Results confirmed the precipitation of Fe, As, Al and Mn in the hydroxide form; Cu and Zn in the form of sulphides. For the selective removal of Cu, Zn, Al and Mn the excellent results were received. Selective precipitation of Fe and As was not so successful since the co-precipitation of Fe and As was later determined as a main mechanism of the precipitate forming.

scholarly journals Dynamic Experimental Study on Treatment of Acid Mine Drainage by Bacteria Supported in Natural Minerals

Energies ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 439 ◽  
Author(s):  
Yanrong Dong ◽  
Junzhen Di ◽  
Xianjun Wang ◽  
Lindan Xue ◽  
Zhenhua Yang ◽  
...  
Keyword(s):  
Acid Mine Drainage ◽  
Treatment Effect ◽  
Mine Drainage ◽  
Ph Value ◽  
Oxygen Demand ◽  
Sulfate Reducing ◽  
Acid Mine ◽  
Oxidation Reduction ◽  
Oxidation Reduction Potential ◽  
Geographic Origins

In order to solve the problem of pollution of acid mine drainage (AMD), such as low pH value and being rich in SO42−, Fe and Mn pollution ions, etc., immobilized particles were prepared by using sugar cane-refining waste (bagasse), a natural composite mineral (called medical stone in China) and sulfate-reducing bacteria (SRB) as substrate materials, based on microbial immobilization technology. Medical stone is a kind of composite mineral with absorbability, non-toxicity and biological activity. The adsorption capacity of medical stone is different according to its geographic origins. Two dynamic columns were constructed with Column 1 filled by Fuxin’s medical stone-enhanced SRB immobilized particles, and Column 2 filled by Dengfeng’s medical stone-enhanced SRB immobilized particles as fillers. The treatment effect on AMD with SRB-immobilized particles enhanced by medical stone from different areas was compared. Results showed that Column 2 had better treatment effect on AMD. The average effluent pH value of Column 2 was 6.98, the average oxidation reduction potential (ORP) value was −70.17 mV, the average removal percentages of SO42−, Fe2+ and Mn2+ were 70.13%, 83.82% and 59.43%, respectively, and the average chemical oxygen demand (COD) emission was 555.48 mg/L.

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