The overall objective of the validation study was to confirm that the ENVIRO-CLEAN PROCESS would meet the heavy metal effluent treatment objectives for a molybdenum waste stream from a dye manufacturer located in the north eastern United States. Approximately ten (10) gallons of molybdenum waste (2 five gallon buckets) were received at Lewis’ Pittsburgh, PA facility. The waste sample was a deep purple color. Some fibrous material was observed in the feed, so the material was coarsely filtered before treatment. A portion of the feed sample was collected and submitted for analysis; the analysis is presented in Table 1.
The balance of the molybdenum waste was processed through the ENVIRO-CLEAN PROCESS pilot carbon unit. The system consisted of a feed pump, pH controller and two (2) carbon columns. Each column contained about 180 grams of Filtrasorb 400 granular activated carbon, manufactured by Calgon Carbon. The flowrate was set at 20 ml/min. The treatment parameter values were based on positive results obtained from a previous field molybdenum removal project1. Effluent samples were collected and analyzed for total molybdenum. This validation study was conducted to verify the system’s capability to remove molybdenum to acceptable levels.
The feed and effluent analysis are presented in Table 1, with the time periods marked in parenthesis, designating when the sample was collected during the test run.
Table 1. Enviro-Clean Effluent Analysis
| Individual Samples | Total Molybdenum (mg/l) |
|---|---|
| Feed | 1.8 |
| Sample #1 (8 hrs) | <0.01 |
| Sample #2 (24 hrs) | <0.01 |
| Sample #3 (32 hrs) | <0.01 |
The processing of the molybdenum waste sample was completed without any mechanical or process difficulties. The effluent was crystal clear with no visible trace of solids or color. The ENVIRO-CLEAN PROCESS was able to produce a low level molybdenum effluent and meet the client’s current discharge limits. The pilot unit’s effluent concentration for total molybdenum averaged