The Octolig® Metal Removal Plant is very simple to operate, and few controls are needed. The Octolig® MRP may be installed next to the plating line or up to 100 yards away. When the pH of the waste stream is above 5.5, the Octolig® MRP may handle the live rinse water directly with no added chemicals. Otherwise, a few grams of caustic soda or sodium carbonate may be added during a shift to raise the pH of the system.
In an electroplating facility, the most effective, efficient, and economical way to employ Octolig® treatment of live-rinse water is to use a separate Octolig® MRP column on each individual plating line. On each line, either two drag-out tanks or spray-rinse-plating-items twice is employed. Many times, a 95-98% portion of the Octolig® treated live rinse water may be returned to the live rinse tank for reuse. See the following flow chart as an example.
When using the Octolig® MRP, another ideal operation method for the plater is to use two drag-out tanks in a series followed by a live-rinse tank. A volume of water equal to four to six times the original drag-out volume from the plating tank is returned to the plating tank. Water from the live-rinse tank is treated by the Octolig® MRP and the Octolig® treated water is recycled back to the live-rinse tank. Each day, a small portion of the live-rinse water is discharged to the sewer and a major portion is recycled.
Spray-rinsing is another option if the plating facility is limited on space.
In an ideal spray-rinsing method, the plater drains the plated items over the plating tank for fifteen to thirty seconds; then the items are spray-rinsed twice with deionized water. After each spray rinse, the plated items are allowed to drain for fifteen to thirty seconds, followed by a rinse in a live-rinse tank. Water from the live-rinse tank is treated by the Octolig® MRP. After the Octolig® treatment, a major portion of the live-rinse water is recycled to the live-rinse tank and a very small portion is discharged to the sewer.
When the plated items are taken directly from the plating tank to the live-rinse tank, the concentration of the heavy metals in the live-rinse water may be 250 ppm. Generally, an electroplater compensates for that by using more water and the concentration of the heavy metals is in the range of 40 ppm. Typically, an electroplater may use 8 GPM of fresh live rinse water. If 8 GPM of rinse water that contains 40 ppm of heavy metals were passed through a single 24 inch diameter Octolig® column, the Octolig® would have to be regenerated after three eight hour shifts. Therefore, precipitation pretreatment is recommended prior to the treatment with the Octolig® MRP.
Batch-precipitation treatment is preferred over continuous-flow precipitation. When using continuous flow, 37% of the initial influent still remains in the tank after the volume of one tank of fresh water has flowed into a live-rinse tank. Continuous-flow precipitation occurs with any system that uses a continuous flow sequence of pH adjustment, mixing, clarification, and filtration. After batch precipitation, the filtered filtrate is passed through the Octolig® MRP. With this method, the Octolig® MRP may operate for longer periods of time, in some cases, as long as 120 eight hour shifts.
An Octolig® MRP has been installed in a plating shop in Nebraska. The plating shop has two plating lines; a nickel line and a chromium line.
Currently, the plating shop uses 2800 GPD of recycled Octolig® treated water on the nickel plating line and only 10 GPD of fresh water. The concentration of the nickel in the plating tank is 100,000 ppm. The nickel plating line drag-out is 1.75 GPD and 7 GPD of spray-rinse water and/or dead-tank rinse water is returned to the plating tank. An average concentration of nickel in the untreated live rinse water going into the Octolig® MRP is 4.1 ppm. Even after several months of operation, the average concentration of the Octolig® treated water is 1.6 ppm. Only a 10 GPD volume of Octolig® treated water is discharged to the sewer.
Without the combination of Octolig® treatment and the spray-rinse operation, a drag-out volume of 1.75 GPD with a nickel concentration of 100,000 ppm would lose and waste 662 grams of nickel each day. With the Octolig® treatment, 96% of that nickel is returned to the plating tank. Each day, a 26.5 gram quantity of nickel is retained in the Octolig® MRP. Only a 10 GPD volume of Octolig® treated rinse water is discharged to the sewer. The 10 gallons contains a maximum of 1.6 ppm of nickel. The 10 gallon discharge contains 0.061 grams of nickel, an amount that is about the size of a small fraction of an aspirin tablet.
With Octolig® MRP treatment, 99.99% of the total daily nickel is retained in the plating line or recovered in the Octolig® MRP. This means that less than 1/100 of 1% of the daily nickel is discharged to the sewer.
The Octolig® MRP has been installed in a Colorado plating shop. The numerous plating lines have copper, nickel, zinc, and chromium present. Rinse waters from separate plating lines are passed through an existing precipitation system.
The precipitation process does not reduce the heavy metal concentrations to below the required limits consistently, so the solution from the precipitation process is passed through the Octolig® MRP to further reduce the heavy metal concentrations.
| Untreated Water | Octolig® Treated Water | |
| Cr | 0.30 ppm | N/D |
| Cu | 0.80 ppm | 0.21 ppm |
| Ni | 0.60 ppm | 0.04 ppm |
| Zn | 4.20 ppm | 0.07 ppm |
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