Technology:
CRF/DAF (Chemical reaction and flocculation and dissolved air flotation):
- DAF system (Model DAF-5) was a skid-mounted unit containing a flotation chamber, including a skimmer, sump, and air dissolving tank
- CRF system (Model CRF-15) included a two-stage chemical reaction tank, a polymer mix preparation tank, pumps, and mixers
- Oleofiltration™ treatment system included a conventional oil/water separator, coalescing unit, and ceramic granule filtration system
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Contaminants:
Total Petroleum Hydrocarbon (TPH)
- concentrations in the bioslurper process wastewater ranged from 5,000 to 21,000 mg/kg
Metals - copper, lead, zinc |
Results:
- The CRF/DAF system removed more than 98% of TPH from the wastewater stream containing an influent concentration of 5,000 mg/kg TPH as compared to the Oleofilter™ which removed between 56% and 90% TPH.
- The CRF/DAF system removed 98.9% of lead and zinc and more than 90% of copper from the wastewater stream whereas the Oleofilter™ removed 75% lead and 71% zinc. In addition, the percent removal of metals by the Oleofilter™ was reported to have varied significantly from sample to sample. Copper concentrations in the influent to the Oleofilter™ were below detection limits; therefore, a percent removal could not be calculated. |
Cost Factors:
- The results of the demonstration were used to estimate full-scale costs. Short-term (6-month) operating costs were calculated for both systems, assuming that the equipment was leased. The estimated cost per month to lease and operate each system was $7,580 for the CRF/DAF (for a six-month total of $45,500) and $3,650 for the OleofilterJ (for a six-month total of $21,900).
- Excluding lease rates, the monthly operating costs for the CRF/DAF and OleofilterJ systems are estimated to be $3,650 and $1,150, respectively.
- Based on these estimates, the CRF/DAF system costs about twice as much to lease and operate as the Oleofilter™ system. |
Description:
The Coastal Systems Station is located in Panama City, Florida along the St. Andrews Bay. AOC 1 is a former fire-fighting training area used from 1955 to 1978, where waste oil and other ignitable such as diesel, gasoline, JP-5 jet fuel, and paint thinner were used during fire training exericse. An estimated 63,000 gallons of flammable hydrocarbons were in this area and light, nonaqueous-phase liquid (LNAPL) was identified during the RCRA Facility Investigation. The Navy selected bioslurping to remove LNAPL from the subsurface. During a pilot-scale test, it was determined that the wastewater generated from the system contained high levels of emulsified hydrocarbons as well as high concentrations of copper, lead, and zinc; high levels also were expected in the full-scale bioslurping system. To identify a cost-effective treatment technology for the full-scale bioslurping system wastewater, the Navy selected two technologies, CRF/DAF and Oleofiltration™, for demonstration. The concentrations in the bioslurper wastewater during the demonstration were TPH as high as 27,000 ppm, and copper, lead, and zinc as high as 228 ppm, 1,430 ppm, and 6,210 ppm, respectively.
The CRF system included a two-stage chemical reaction tank, a polymer mix preparation tank, pumps, and mixers. The skid-mounted DAF system included a flotation chamber, including a skimmer, sump, and air dissolving tank. The 10 gpm capacity Oleofiltration™ treatment system included a conventional oil/water separator, coalescing unit, and ceramic granule filtration system. For the CRF/DAF system, the influent water flow rate was 1.5 to 6.5 gpm. The retention time for the two-stage CRF unit was 37 to 160 minutes for Stage 1 and 22 to 94 minutes for Stage 2. The retention time for the DAF unit was 13 to 55 minutes. For the Oleofiltration™ treatment system, the influent flow rate ranged from 5 to 7.5 gpm with a retention time of 25 to 37 minutes. |
