scholarly journals Application of Acidophilic Microorganism in the Metal Enrichment of Electroplating Sludge Use the Membrane Bioreactor

2020 ◽  
Author(s):  
Yiran Yang ◽  
Huichao Chu ◽  
Can Qian ◽  
Chunyou Jia ◽  
Shiyue Qi ◽  
...  
Keyword(s):  
Acid Production ◽  
Sewage Treatment ◽  
Membrane Bioreactors ◽  
Metal Enrichment ◽  
Cycle Number ◽  
Key Technology ◽  
Sulfuric Acid Production ◽  
Electroplating Sludge ◽  
Treatment Research ◽  
High Density Cell

Abstract Background: Bioleaching is an important technology for treating electroplating sludge. Previous researches have focus on improving the leaching rate of metals in electroplating sludge by bioleaching. However, the concentration of heavy metals in the leachate after single leaching was lower, which is quite unfavorable for subsequent metal recovery. Additionally, membrane bioreactors (MBRs) have been widely used in the field of sewage treatment. Research on the application of bioleaching technology combined with MBRs to enrich metals in electroplating sludge has not been reported. Therefore, in this study, we first combined bioleaching technology and MBRs for metal enrichment in electroplating sludge to obtain the key technology of "acid production - electroplating sludge leaching - leachate regeneration -repeated electroplating sludge leaching - achievement of valuable metal enrichment".Results: In this research, through scaling up from the laboratory scale (shake flasks) to a factory-scale application (10 m³ membrane bioreactors), we mastered the key technology of acid production by acidophilic microorganism, and the acid solution can be repeatedly used for metal leaching. The results showed that the MBR maintained high-density cell growth (≈2.1×109/mL) and a stable sulfuric acid production rate (850 L/h) throughout the entire operational period. Under the above conditions, the maximum cycle number (10 times) for enrichment of the target metals in the electroplating sludge was obtained. Additionally, after the end of the cycle enrichment process, the concentrations of the target metals Ni+, Cu2+, and Zn2+ were 13.867 g/L, 18.118 g/L and 21.075 g/L, respectively, which were highly enriched.Conclusions: This study first solved the difficulties in the industrialization of bioleaching electroplating sludge through combining bioleaching technology and MBRs. Furthermore, this research can provide a demonstration project for the industrial application of MBR-bioleaching technology in electroplating sludge, with a view to applying this technology to the disposal of more types of hazardous waste.

Pilot-Scale Bioleaching of Metals from Pyritic Ashes

2017 ◽  
Vol 262 ◽  
pp. 147-150
Author(s):  
Elina A. Vuorenmaa ◽  
Jarno Mäkinen ◽  
Tero Korhonen ◽  
Raisa Neitola ◽  
Anna H. Kaksonen
Keyword(s):  
Sulfuric Acid ◽  
Acid Production ◽  
Pilot Scale ◽  
Solution Ph ◽  
Mineral Salts ◽  
Sulfuric Acid Production ◽  
Stirred Tank Reactors ◽  
Working Volume ◽  
Guideline Values ◽  
The Government

Solid waste from sulfuric acid production may contain relatively high levels of metals such as Fe, Zn, Co, Cu and As that are harmful if inappropriately disposed of in the environment, but may be a valuable resource if metals can be recovered. The objective of this research was to investigate the pilot-scale acid bioleaching of metals from pyritic ashes, originating from the roasting of pyrite ores for sulfuric acid production and consisting mainly of hematite. Bioleaching was carried out at 25 °C in pilot-scale continuously stirred tank reactors (CSTR), with 50 L working volume in mineral salts medium supplemented with trace elements, 1 % (w/v) elemental sulfur and with pyritic ash pulp densities 10 % and 20 %. The reactors were inoculated with a mixed culture of iron- and sulfur-oxidising acidophiles containing Acidithiobacillus (At.) ferrooxidans, At. thiooxidans/albertensis, At. caldus, Leptospirillum ferrooxidans, Sulfobacillus (Sb.) thermosulfidooxidans, Sb. thermotolerans and some members of Alicyclobacillus genus. Metal leaching yields from pyritic ashes in the CSTR after 32 days were 54.6-56.7 % Cu, 41.7-43.2 % Zn, 1.7-1.8 % Co, 3.0-5.4 % As and 0.3-0.5 % Fe. Solution pH decreased during the experiment from 2.9 to 1.9-2.2. Elemental analysis using X-ray fluorescence showed that the contents of metals, except for As, in the leach residue were below the higher guideline values given in the Government decree on the assessment of the soil contamination and remediation needs by the Ministry of the Environment, Finland. Bioleaching facilitated the extraction of metals from pyritic ashes and the mitigation of environmental risks related to the residue disposal for other metals except for As.

scholarly journals Aeration optimization of large-scale membrane bioreactors in a sewage treatment plant

2019 ◽  
Vol 14 (1) ◽  
pp. 198-202
Author(s):  
M. Tang ◽  
J. Liu
Keyword(s):  
Large Scale ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Membrane Bioreactors ◽  
Fouling Control ◽  
Conventional Activated Sludge ◽  
Plant Trial ◽  
Activated Sludge Processes ◽  
Discharge Criteria

Abstract Increasing stringency of environmental discharge standards has triggered an industry-wide inclination towards membrane bioreactors over conventional activated sludge processes to ensure fulfilment of environmental discharge criteria. Yet, despite its plentiful advantages, high aeration costs remain as a key deterrent to the widespread adoption of the MBR technology. This backdrop created an impetus for a wastewater treatment company to develop an efficient MBR air scouring protocol that can be realized in existing plants without retrofitting. Known as pulsed cyclic aeration, plant trial applications have demonstrated that fouling control and aeration savings can be improved by >30%, resulting in scouring energy consumptions that can be as low as 0.049 kWh/m3.

Dielectric Barrier Discharge Structure Design for Sewage Treatment

2014 ◽  
Vol 1037 ◽  
pp. 57-60
Author(s):  
Jian Ping Jia ◽  
Li Cai ◽  
Shou Bo Zhang ◽  
Yuan Zhao
Keyword(s):  
Dielectric Barrier Discharge ◽  
High Efficiency ◽  
Barrier Discharge ◽  
Sewage Treatment ◽  
Structure Design ◽  
Treatment Technology ◽  
Temperature Plasma ◽  
Dielectric Barrier ◽  
Discharge Structure ◽  
Treatment Research

The problem of the urban water shortage and water pollution is becoming problem more and more serious. Therefore, governments around the world pay close attention to the application of sewage treatment technology, especially that with high efficiency, low energy consumption and strong operability. Dielectric barrier discharge (DBD) can produce low temperature plasma under atmospheric pressure, and the application of the technology for sewage treatment research gradually becomes to be one of hot research. In this paper, the dielectric barrier discharge structure is designed, and the plasma produced is used for sewage treatment research. The system adopts coaxial type discharge structure. The research shows that the structure is safe and reliable. And, it has low discharge power and can discharge uniformly. So, the plasma produced by dielectric barrier discharge can be convenient and easy to used in sewage treatment, and the result is effective.

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