An evaluation of heavy metals and oil and grease contents in cooling water and sludge of a typical steel rolling mill

Doris, Primus (2001) An evaluation of heavy metals and oil and grease contents in cooling water and sludge of a typical steel rolling mill. [Final Year Project Report] (Unpublished)

	PDF Doris Primus.pdf Download (7MB)
	PDF (Please get the password by email to repository@unimas.my, or call ext: 3914/ 3942/ 3933) Doris Primus ft.pdf Restricted to Registered users only Download (19MB)

Abstract

This research work investigates recycled cooling water treatment processes of a steel rolling mill, and subsequently recommend cost-effective treatment methodologies to prolong the life ofcooling water before disposal, and to meet the effluent standards of the Department of Environment (DOE), Malaysia. The characteristics of the sludge generated from the cooling water treatment plant of are also evaluated, with special focus on heavy metal content.The objectives of this study are to evaluate and improve the existing cooling water treatment technology and to evaluate heavy metals content in the sludge of a typical steel rolling mill. This study specially focuses on alternative cost-effective oil and grease (tramp oil) removal system from cooling water so as to prolong the life and improve the quality of recycled cooling water. Recommendations on the removal of other dissolved substances such as iron, color, odor, and control of biological growth in the recycled cooling water treatment process are included in this study. The study shows that the effluent temperature approximately ranges 52°e to 55°e, which is about 12°e to 15°e higher than the DOE maximum allowable effluent temperature. Iron concentration levels range 1.5 mg/L to 1.8 mgIL and the DOE standard is 5.0 mg/L. The concentration of lead in the cooling water ranges approximately from 0.3 to 0.6 mg/L as compared to DOE standard of 0.5 mglL. In this case, the content of lead in the cooling water is on the high side, and the release into inland waterways is not in compliance with DOE standard. The existing cooling water treatment facility does not include processes to treat or lower the content of the dissolved metals. The metal content in the water would be substantially reduced by chemical processes such as "Chemical Precipitation" or "Chemical Oxidation". The content ofoil and grease in the cooling water ranges from about 400 mg/L to 920 mg/L, which is about 40 to 90 times higher than DOE maximum allowable limit. High level of oil and grease in the effluent can be attributed to the facts that the existing oil removal system is inadequate. To comply with DOE effluent limits, there is a need to substantially lower the oil and grease level. To do so, the existing oil removal system would have to be substituted by another cost-effective phase separation system.

Actions (For repository members only: login required)

View Item