Sand Filter Replacement | STiR Walnut Shell Filter
METAL PROCESSING COMPANY - SAND FILTER REPLACEMENT
A metal processing company operates in the US. They need to remove TSS, oil and grease, and heavy metals from the process water before it can be discharged.
This company had two sand filters which had 1) low removal efficiency, 2) high maintenance cycles as the sand was replaced each year, 3) high waste generation, which needed to be reprocessed, and 4) potential OSHA violations as sand is classified as a dusting hazard and plant personnel had significant exposure to sand during media change-outs.
A STiR filter was evaluated for a two month period to determine how it would perform in the application. A single STiR filter was selected to replace both sand filters as it 1) provided 90% removal at 5 micron (a 90% improvement), 2) offers permanent walnut shell media which does not require replacement, 3) has an extremely low backwash volume (1.5% of throughput) which reduced cost to treat by 10%, and 4) removed the potential silicosis hazard from the plant as the walnut shells are permanent, require no replacement, and inert.