Oberlin Filtration technology using DuPont filter media was successfully demonstrated in cleaning contaminated groundwater at the Palmerton Zinc Pile Superfund Site. This Superfund site was the result of a zinc smelting factory that deposited 33 million tons of smelting waste on its grounds. This waste contaminated the groundwater with heavy metals including zinc, cadmium, copper, lead and selenium, creating grave health risks to the local population. Under the Superfund Innovative Technology Evaluation, the Oberlin Filter successfully demonstrated its ability to remove the hazardous heavy metals from the groundwater. The Oberlin Filter technology was able to remove 99.95% of the zinc, 99.95% of the TSS, and produced dry cakes that passed the “Paint Filter Liquids Test”, 41% cake solids, filtrate that met NPDES discharge limits, and cakes that passed both the EP Toxicity and the TCLP test.

 

Below is a summary of the report of the Superfund Innovative Technology Evaluation for the Oberlin Filter and the Palmerton Zinc Pile Superfund.

 

This report evaluates the Oberlin microfiltration technology's ability to remove metals (present in soluble or insoluble form) and particulates from liquid wastes while producing a dry filter cake and a filtrate that meet applicable disposal requirements. This report also presents economic data from the Superfund Innovative Technology Evaluation (SITE) demonstration and, as available, three case studies.

 

The Oberlin microfiltration technology combines Oberlin's automatic pressure filter with DuPont's microporous Tyvek® filter media. It is designed to remove particles that are 1.0 micron in diameter, or larger, from liquid wastes, such as contaminated groundwater. Groundwater with dissolved metals must first be treated to convert the dissolved metals into an insoluble form prior to microfiltration.

Superfund Innovative Technology Evaluation

The Oberlin microfiltration technology demonstration was conducted under the SITE program at the Palmerton Zinc Superfund site in Palmerton, Pennsylvania, in April and May 1990. During the demonstration, the microfiltration system achieved zinc and total suspended solids (TSS) removal efficiencies of about 99.95 percent, and a filter cake solids content of 41 percent. The filter cake contained no free liquids, and a composite sample from all the demonstration runs passed both the extraction procedure toxicity test and the toxicity characteristic leaching procedure (TCLP) test. The filtrate met applicable National Pollutant Discharge Elimination System permit limits for metals and TSS but not for pH; the filtrate pH was typically 11.5 while the upper pH limit is 9.

 

The results from three case studies are also summarized in this report. All three facilities treated process wastewaters containing metals and TSS ranging from several parts per million to several percent. The filtrates at all three facilities met their respective discharge limits. Filter cake at one facility is a mixed waste and is further stabilized and solidified with cement prior to land disposal. At another facility, filter cake did not pass the TCLP test and is considered a hazardous waste. No filter cake information was available from the third facility.

 

Possible sites for applying this technology include Superfund and other hazardous waste sites that have groundwater and other liquid wastes contaminated primarily with metals and particulates. Sources of metal-bearing wastes include electroplating and metal finishing facilities, electronic component manufacturers, aluminum and other metal forming facilities, and uranium processing facilities. 

NR

30

2.4

NR

0.7

0.2

NR

NR

NR

NR

Must Pass

0.1

0.8

0.25

<0.1*

0.025

0.005

0.003

0.040

>40

Yes

Yes

Property                   Raw Groundwater      Dupont/Oberlin Filter      Discharge Limits**

>1,000  

1,700  

500  

50  

0.1

0.5

0.2

0.1

---

No

No

* Detection Limit.

** NPDES discharge limits.

NR=Not Regulated.

Turbidity (NTU)

TSS (ppm)

Zinc (ppm)

Manganese (ppm)

Lead (ppm)

Cadmium (ppm)

Copper (ppm)

Selenium (ppm)

Cake % Solids

Cakes Pass EP Tox?

Cakes Pass TCLP?

OBERLIN FILTRATION TECHNOLOGY DEMONSTRATION BY EPA AT PALMERTON, PA SUPERFUND SITE