Determination of Heavy Metals in the Effluent Plating Units of Isfahan Province

Document Type : Technical Note

Authors

1 Instructor of Iranian Research Organization for Science and Technology

2 M.Sc., Water and Wastewater Consulting Engineers

3 Operational Manager of Iranian Water and Wastewater Treatment Plants

Abstract

There are more than tens of plating plants in Isfahan province. These units are operated as small and private or as a part of major plant. To determine pollution in return flow of these units, all of these plating units in Isfahan were monitored and sampled. In this research, 52 plating units were identified and investigated. The results show that 44.23% of units are located in urban areas, 28.8% in country-side, 15.4% in industrial zones and 11.5% in industrial towns. Among identified plating units, more than half of them (55.8%) were near industrial areas. The studied units maily used Nickel and Cadmium as main materials. The effluents discharged into septic wells, surface water, descent reservoirs and municipal networks in the rate of 78.3, 10.9 , 6.5 and 4.3 percent respectively. In some units, there were few unusable septic wells due to overfilling with metal sediment. The overflow rate of discharge of plating process in studied units varied from 0.5 to 5.0m3/d depending upon type of plating process. The average discharge in these units was found 1.3 m/day. The concentration of zinc ion was in the range of 3.84 to 49.92 mg/l. The average concentration of nickel, chromium and copper were 3.85±2.2 , 24.43±7.3, 14.51±15.2 and 14.22±10 mg/l respectively. The average concentration of cyanide was 0.012 mg/l. In this study, strategies for reducing discharge of these units and its pollutants and also appropriate sewage treatment to eliminate cyanide, zinc, chromium and copper are suggested.

Keywords


1- خوش‌منش، ا. (1371). ترکیب فلزات سنگین در پساب تعدادی از واحدهای آبکاری شهر اصفهان و خطرات زیست‌محیطی آنها م. آب و فاضلاب، 8 ، 15- 10.
2- موثقی، ک. (1379). بهینه‌سازی حذف سیانید از پسابهای صنعتی در مقیاس پایلوت. م. آب و فاضلاب، 25، 45 -42.
3- فرازمند، ع. (1380). تصفیه پسابهای حاوی فلزات سنگین به روش احیای باکتریهای سولفات. م. آب و فاضلاب، 37، 23-16.
4- فردوسی، س. (1372). مدیریت پسماندهای شیمیایی، سازمان بازیافت و تبدیل مواد، تهران.
5- Matthew, G., and Kennedy, J. (1999). “Recovery of Heavy Metals from Electroplating Sludge and Stainless Steel Pickle Waste Liquid by Ammonia Leaching Method. ” J.Journal of Environmental Sciences, 11 (3), 4,381.