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

Abstract

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%.

Keywords

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

Çevresel Büyük Risk Maden Atıksularının Kimyasal Çöktürme Yöntemi ile Arıtım Örneği

Abstract

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.

Keywords

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

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