Industrial Wastewater Treatment Success Stories
Oil Water Emulsion Wastewater Treatment Industry
Oil Recovery - Improved Efficiencies
A refinery was having several upsets in their biological system due to high loadings of oils after pretreatment API separators and dissolved air flotation units. The variations in pH as well as oil loading is difficult to control and causes upsets in the downstream processes.
In reviewing the situation, it was determined that a more efficient method of removal of such oils would be a great benefit to the wastewater system as well as a potential to recover more oil and return it as slop oil to the slop oil recovery unit process at the refinery.
The laboratory testing was setup to see what amount of oil recovery was possible. Several emulsions were made using motor oil at 10, 20 and 30% by volume mixed with soap and water and then blended in a blender to make a uniform emulsion. Using Floccin 1105, it was determined that 400 ppm was sufficient to break the 30% oil emulsion into water and floating oily sludge. The sludge was visually tested and was high in oil content.
Based on an Return On Investment analysis, the cost of the Floccin 1105 is very small as compared to the value of the recovered oil and reduction in biological loading to the secondary treatment system. In fact, the onsite testing will confirm a reduction in wastewater loading from recovering the oil and the potential for further cost savings to reduce the aeration horsepower due to lower influent COD levels.
Industrial Waste Facility
Lower Levels Meet Discharge Permit
An industrial wastewater treatment facility that imports wastewater from a variety of industries was having difficulty meeting their waste discharge permit. The facility receives waste from industries such as plating (chrome, nickel, zinc, and others), pressure washing, cosmetics, metal processing, to name a few. The wastewater is speciated for metals, volatiles and semi-volatiles and depending on the results separated into different tanks for specific treatment scenarios.
The facility was having difficulty treating a waste stream containing Chrome, Nickel, and Zinc. Bench scale testing results are shown below:
| Analyte | Max Daily Limit | Untreated | Treated |
|---|---|---|---|
| Ag | 0.12 | 0.865 | 0.100 |
| As | 0.162 | 0.513 | 0.160 |
| Ba | 0.427 | 0.349 | 0.130 |
| Cd | 0.474 | 0.286 | 0.090 |
| Co | 0.192 | 0.017 | ND |
| Cu | 0.405 | 2.689 | 0.370 |
| Cr | 0.947 | 7.034 | 0.050 |
| Mo | 1.01 | 1.252 | 0.910 |
| Ni | 3.95 | 4.060 | 0.630 |
| Pb | 0.222 | 0.5268 | ND |
| Sb | 0.237 | 0.5660 | ND |
| Se | 1.64 | 0.480 | ND |
| Sn | 0.409 | 2.684 | 0.430 |
| Ti | 0.0947 | 1.190 | 0.070 |
| V | 0.218 | 0.086 | ND |
| Zn | 2.87 | 22.880 | 0.290 |
The treatment included the use of an ORP control system and IE-061 as a metal precipitant. The sample was pH adjusted from a pH of 1.79 to 10.0, which dropped the ORP reading from 222 mV to -86 mV. The IE-061 was added until the ORP stopped declining at -407mV. The sample was then flocculated with Floccin-E. After pouring the sample through a coffee filter to simulate the clarification step, the water was analyzed with the results shown above.
The facility has never achieved such good results with their process using ferric sulfate as a coagulant, lime for pH adjustment to 10.0, a DTC based metal precipitate, and an anionic flocculant. Their new process will use lime for pH adjustment, IE-061, and Floccin-E with lower residual metals at a significantly reduced cost/gallon treated.
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