Removal of Heavy Metals from Waste

The Unipnre Environmental, Unipnre process technology is a unique iron co-precipitation method for removal of heavy metals from waste streams or groundwater. It can act as a primary metal-removal system or as a polishing step to an existing treatment system. The reactor mod-nle replaces the nentrahzation tank in a conventional wastewater treatment system. The process prodnces solids that are extremely insolnble in water and mild acid solutions. 

Sulffde Precipitants. The removal of heavy metals from waste waters using soluble sulfides has been studied extensively. Peters and Ku (13) showed that pH strongly affects the removal of heavy metal sulfides from waste water. Their data showed that the solubilities of most heavy metal sulfides, other than arsenic (HI) sulfide, decreases up to about pH 9. Since most phosphate fluid fertilizers, such as 10-34-0 and 11-37-0, have a pH in the range of 6 to 7, these data indicate that concentrations of several heavy metals in phosphate fluid fertilizers could be reduced to very low levels by precipitation with inorganic sulfide reagents. The use of soluble sulfides to precipitate heavy metals from WPA has also been reported. Both Maruyama (14) and Berglund (15) have... 

Denitrification and Removal of Heavy Metals from Waste Water by Immobilized Microorganisms... 

In this chapter, we provide a qualitative overview of the EK soil remediation experiences reported from laboratory and field with industrially polluted soils regarding the most common heavy metals and soil types. Based on the results reported in the literature, a general guideline of suitable remediation conditions and possible enhancements is given. Lastly, a short overview of published works on EK remediation (EKR) removal of heavy metals from waste materials other than soil is given, highlighting the similarities and differences among material characteristics that influence remediation. 

Scott, M. C. (1978), Sulfex - A new Process Technology for Removal of Heavy Metals from Waste Streams, Proceedings of the 32nd Industrial Waste Conference, May, 1977, Purdue University, Ann Arbor Science, Ann Arbor, Michigan, pp. 622-29. 

E. A. Ayuso and A. G. Sanchez, Removal of heavy metals from waste waters by natural and Na-exchanged bentonites. Clays Clay Minerals, 51 (2003), 475-80. 

The two water desalination applications described above represent the majority of the market for electrodialysis separation systems. A small application exists in softening water, and recently a market has grown in the food industry to desalt whey and to remove tannic acid from wine and citric acid from fruit juice. A number of other applications exist in wastewater treatment, particularly regeneration of waste acids used in metal pickling operations and removal of heavy metals from electroplating rinse waters [11]. These applications rely on the ability of electrodialysis membranes to separate electrolytes from nonelectrolytes and to separate multivalent from univalent ions. 

Zeolites are very efficient for the removal of heavy metals from industrial waste water and drinking water (6, 8). There are particularly good prospects for the... 

C. C. Nesbitt and T. E. Davis, Removal of Heavy Metals from Metallurgical Effluents by the Simultaneous Precipitation and Flotation of Metal Sulfides Using Column Cells, in Extraction and Processing for the Treatment and Minimization of Wastes, J. Hager, B. Hansen, W. Imrie, J. Pusateri, and V. Ramachandran (eds.), TMS, Warrendale, PA, 1994, pp. 331-342. 

Mitchell, G. D. Total removal and recovery of heavy metals from waste water. Institute for Interconnection and Packaging of Electronic... 

Ottosen LM, Kristensen IV, Pedersen AJ, Hansen HK, VUlumsen A, Ribeiro AB. (2003). Electrodialytic removal of heavy metals from different solid waste products. Separation Science and Technology 38(6) 1269-1289. 

Pedersen AJ, Ottosen LM, Villumsen A. (2005). Electrodialytic removal of heavy metals from municipal solid waste incineration fly ash using ammonium citrate as assisting agent. Journal of Hazardous Materials 122(1-2) 103-109. 

Griffin RA, Frost RR, Shimp NF. (1976). Effect of pH on removal of heavy metals from leachates by clay minerals. Residual management by land disposal. Proceedings of the Hazardous Waste Research Symposium (ed. WH Fuller), EPA-600/9-76-015. February 2-4, Cincinnati, OH U.S. Environmental Protection Agency, pp. 259-268. 

Chapter 11 by Popa et al. is devoted to the use of chelating resins obtained by the chemical modification of their surface with different phosphorus pendant groups for the removal of heavy metals from various industrial waste effluents. It is shown that modification of the polymeric matrix through phosphorylation of its surface with different phosphorus pendant groups leads to an increase in the adsorption efficiency of the polymer in the removal of metal ions from various aqueous solutions. 

Nomanbhay, S. M. and Palanisamy, K. (2005). Removal of heavy metal from industrial waste-water using chitosan coated oil palm shell charcoal. Electronic Journal of Biotechnology 8, 43-53. 

Biosorption is an efficient and economical method that can be used for the removal of heavy metals from wastewaters. The majority of recent biosorption smdies were conducted with low-cost agricultural waste such as sunflower stalks [14,15], orange peel [16], coconut cash [17,18], ohve stone [19, 20], steel-making slag [21], tree fern [22], olive tree pruning [23], rice husk [24], peanut hull pellets [25], and grape stalk [26,27], and all of them have been identified as potential biosorbents for heavy metal removal. 

Ahluwalia SSD. Goyal removal of heavy metals by waste tea leaves from aqueous solution. Eng Life Sci 2005 5 158-162. 

Pollard SJT, Fowler GD, SoUars CJ, Perry R (1992) Low-cost adsorbents for waste and wasteweiter treatment areview. Sci Total Environ 116(l-2) 31-52 Qdais HA, Moussa H (2004) Removal of heavy metals from wastewater by membrane processes a comparative study. Desalination 164(2) 105-110 Rahman MA, Muneer M (2005) Photocatalysed degradation of two selected pesticide derivatives, dichlorvos and phosphamidon, in aqueous suspensions of titanium dioxide. Desalination 181(1-3) 161-172... 

Even when not specifically designed for the removal of heavy metals, most waste-treatment processes remove appreciable quantities of the more troublesome heavy metals encountered in wastewater. Biological waste treatment effectively removes metals from water. These metals accumulate in the sludge from biological treatment, so sludge disposal must be given careful consideration. 

Ngah, W.S.W. and Hanafiah, M.A.K.M., Removal of heavy metal ions from wastewater by chemically modified plant wastes as adsorbents A review, Bioresource Technology, 99, 3935-3948, 2008. 

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