Major Environmental Risk: An Example of Treatment of Mining Wastewater by Chemical Precipitation Method

Öz

The mining industry uses large volumes of water. A large part of the water used in the mining process becomes wastewater. Mine wastewater contains high amount of pollutants. Major pollution occurs in the receiving environment as a result of the mining wastewater being discharged to the receiving environment without being treated. It is very important to treat mine wastewater in order to prevent environmental pollution and to make mining processing facilities sustainable. In the study, the treatment of heavy metal as Al, Mn, Fe, Zn, Ba and Sb, Ca+2 and Mg+2 cations and SO4 from the wastewater of a mining processing plant in the Black Sea region by chemical precipitation (CP) method used Ca(OH)2 was investigated. The effects of mixing speed and precipitant amount on removal efficiency were investigated. It was seen that 100 rpm as fast mixing speed and 15 rpm as slow mixing speed were suitable. At these values, it was determined that the heavy metal concentration was removed from the environment with high removal efficiencies, and the removal of Ca and Mg ions remained at a low level. Although the increase in the amount of Ca(OH)2 did not affect the heavy metals with high removal efficiency, it caused a slight increase in the heavy metals with lower removal efficiency. While the increase in Ca(OH)2 amount increased the removal efficiency of Mg and sulfate ions, it decreased the removal efficiency of Ca ion. The results showed that while the CP method was suitable for heavy metal removal from mine wastewater with a success rate of approximately 99.9%, an appropriate advanced treatment process should be used after CP, since the hardness removal was approximately 40% and the sulfate removal was approximately 32%.

Anahtar Kelimeler

• Mine wastewater
• chemical precipitation
• heavy metal
• hardness
• treatment

Çevresel Büyük Risk Maden Atıksularının Kimyasal Çöktürme Yöntemi ile Arıtım Örneği

Öz

Madencilik sektörü büyük hacimlerde su kullanmaktadır. Maden işleme aşamasında kullanılan suyun büyük bir kısmı atıksu haline gelmektedir. Maden atıksuları yüksek miktarda kirletici içermektedir. Maden atıksularının arıtılmadan alıcı ortamlara verilmesi sonucunda alıcı ortamda büyük kirlilik oluşmaktadır. Çevre kirliliğinin engellenmesi ve maden işleme tesislerinin sürdürülebilir olabilmesi için, maden atıksularının arıtılması çok önemlidir. Çalışmada Karadeniz Bölgesinde bulunan bir maden işleme tesisi atıksularından Al, Mn, Fe, Zn, Ba ve Sb gibi ağır metaller, Ca+2 ve Mg+2 katyonları ile SO4’ün kimyasal çöktürme (KÇ) yöntemi Ca(OH)2 kullanılarak arıtımı incelenmiştir. Karıştırma hızı ve çöktürücü miktarının giderim verimine etkileri incelenmiştir. Hızlı karıştırma hızı ve yavaş karıştırma hızı incelenmiş ve sırasıyla 100 rpm ve 15 rpm değerlerinin uygun olduğu görülmüştür. Bu değerlerde ağır metal konsantrasyonun yüksek giderim verimlerinde ortamdan uzaklaştırıldığı, Ca+2 ve Mg+2 iyonlarının gideriminin düşük seviyede kaldığı belirlenmiştir. Ca(OH)2 miktarındaki artış, yüksek giderim verimi olan ağır metaller için çok etki etmemekle birlikte, daha düşük giderim verimi olan ağır metallerde bir miktar artışa sebep olmuştur. Ca(OH)2 miktarındaki arıtış Mg ve sülfat iyonlarının giderim verimini artırırken, Ca iyonunun giderim verimini azaltmıştır. Sonuçlar, maden atık suyundan ağır metal giderimi için yaklaşık olarak %99.9 oranında başarı ile KÇ yönteminin uygun olduğunu gösterirken, sertlik giderimi yaklaşık %40 ve sülfat giderimi yaklaşık %32 oranında gerçekleştiği için KÇ sonrasında uygun bir ileri arıtım prosesinin kullanılması gerektiğini göstermiştir.

Anahtar Kelimeler

• Maden atıksuyu
• kimyasal çöktürme
• ağır metal
• sertlik
• arıtım

Kaynakça

1. Almasri D, Mahmoud KA, Abdel-Wahab A, 2015. Two-stage sulfate removal from reject brine in inland desalination with zero-liquid discharge. Desalination 362: 52–58.
2. APHA, Standards Methods of Examination of Water and Wastewater. 23rd. Edition, 5-21 (2017).
3. Calzadilla A, Rehdanza K, Richard S, 2015. Water scarcity and the impact of improved irrigation management: a computable general equilibrium analysis. Agricultural Economics 42: 305–323.
4. Fang P, Tang Z, Chen X, Huang J, Tang Z, Cen C, 2018. Removal of high-concentration sulfate ions from the sodium alkali FGD wastewater using ettringite precipitation method: Factor assessment, feasibility, and prospect. Journal of Chemistry, doi.org/10.1155/2018/1265168.
5. Hosseini SS, Bringas E, Tan NR, Ortiz I, Ghahramani M, Shahmirzadi MA, 2016. Recent progress in development of high performance polymeric membranes and materials for metal plating wastewater treatment: a review. Journal of Water Process Engineering, 9: 78-110.
6. Huisman JL, Schouten G, Schultz C, 2006. Biologically produced sulphide for purification of process streams, effluent treatment and recovery of metals in the metal and mining industry. Hydrometallurgy, 83. 106-113.
7. Kartic DN, Narayana HA, and Arivazhagan M, 2018. Removal of high concentration of sulfate from pigment industry effluent by chemical precipitation using barium chloride: RSM and ANN modeling approach. Journal of Environmental Management, 206: 69–76.
8. Kaykıoğlu G ve Balcı CN, 2021. Zeytin karasuyunun ön arıtımında asitle parçalama ve kireçle çöktürme uygulamalarının karşılaştırılması. European J. Eng. App. Sci. 4(2), 45-49.

9. Khaldi A, Abusharkh B, Khaled M, Atieh MA, Nasser MS, 2015. Adsorptive removal of cadmium (II) ions from liquid phase using acid modified carbon-based adsorbents. Journal of Molecular Liquids, 204: 255-263.
10. Ku Y, and Jung IL, 2001. Photocatalytic reduction of Cr(VI) in aqueous solutions by UV irradiation with the presence of titanium dioxide. Water Research, 35: 135-142.
11. Mahmud HN, Huq AK, and Yahya R, 2016. The removal of heavy metal ions from wastewater/aqueous solution using polypyrrole-based adsorbents: a review. RSC Advances, 6: 14778-14791.
12. Nemati M, Hosseini SM, Shabanian, M, 2017. Novel electrodialysis cation exchange membrane prepared by 2-acrylamido-2-methylpropane sulfonic acid; heavy metal ions removal. Journal of Hazardous Materials, 337: 90-104.
13. Nenov V, Lazaridis NK, Blöcher C, Bonev B, Matis KA, 2008. Metal recovery from a copper mine effluent by a hybrid process. Chemical Engineering and Processing: Process Intensification, 47 (4): 596-602.
14. Park JH, Choi GJ, Kim SH, 2014. Effects of pH and slow mixing conditions on heavy metal hydroxide precipitation. Journal of Korean Organic Resources and Recycling Association 22: 50–56.
15. Reshadi MAM, Bazargan A, and McKay, G, 2020. A review of the application of adsorbents for landfill leachate treatment: focus on magnetic adsorption. Science of the Total Environment, 138863.
16. Rodríguez R, Espada JJ, Gallardo M, Molina R, Lopez-Munoz MJ, 2018. Life cycle assessment and techno-economic evaluation of alternatives for the treatment of wastewater in a chrome-plating industry. Journal of Cleaner Production, 172: 2351-2362.
17. Yang X, Liu L, Tan W, Qiu G, Liu F, 2018. High-performance Cu2+ adsorption of birnessite using electrochemically controlled redox reactions. Journal of Hazardous Materials, 354: 107–115.
18. Zhao Y, Kang D, Chen Z, Zhan J, Wu X, 2018. Removal of chromium using electrochemical approaches. International Journal of Electrochemical Science, 13: 1250–1259.