Over 50 years of experience in liquid solid separation

Heavy Metal Wastewater Treatment

Heavy metal water contamination is a by-product of the industrial world. Industries in their manufacturing practice create wastewater laden with heavy metals. Untreated, this wastewater makes it into our water supply with grave health consequences on people and the environment. Heavy metals are dangerous because they tend to bioaccumulate and increase in the concentration in a biological organism over time. The Oberlin Filter has extensive experience in removing heavy metals from industrial wastewater. Uranium, aluminum, nickel, lead, zinc, copper, chromium, barium, titanium, neodymium, bismuth are some of the heavy metals we remove from water.

 

The Oberlin Filter technology allows industries to treat their wastewater on site and become an integrated part of their manufacturing process. The filtered water can often be recycled and reused at the manufacturing plant, greatly reducing the amount of water used. If discharging the water is required, the Oberlin Filter meets regulated water discharge limits for a safe disposal into municipal sewers. The filtered water no longer poses a risk of heavy metal contamination that can adversely affect the water supply. The removed heavy metals are in a dry solid form. The Oberlin Filter technology is a highly effective way to treat the wastewater at its source to prevent pollution of water. The Oberlin Filter provides low cost metals removal/stabilization in one simple operation. Please see below for more examples of the Oberlin Filter's ability to clean wastewater.

 

Chemical Plant Hazardous Wastewater Treatment

This application involved treatment of a high solids wastewater (WW) stream that was shipped off-site at considerable cost (i.e., >$2MM annually). The stream contained a fairly large amount of surfactant as well, which complicated the treatment and subsequent solids removal prior to discharge through a carbon bed-polishing step to the local river. Lab tests showed that by combining high charge cationic polymer along with powdered activated treatment ( to remove surfactant) and Filter Aid, the WW could be effectively filtered and also reduce the load to the polishing carbon beds prior to discharge to the local river. As a consequence, this treatment protocol was adopted along with a Oberlin APF, and startup commenced in early 2004. Tests of filtrate showed that both Surfactant and Haz levels were well below 0.1 ppm The Oberlin APF process for this very difficult wastewater has been operating successfully for almost 10 years.

Electronics Manufacturing Plant Wastewater

Electronics Manufacturing Plant WastewaterThis plant’s effluent exceeded the local sewer authority’s lead discharge limit. As a consequence, the plant was mandated to cease discharge and dispose of their wastewater in an off-site hazardous waste landfill at a $0.55/gallon cost. Two Oberlin Filters were installed and the dry cake feature significantly reduced waste volume. These units repaid their cost in three months of operation based on disposal cost savings alonel6

 

The below table details actual plant[operation and compares the Oberlin Filter's effluent with the plant’s discharge limits. As shown, these units reduced the effluent Total Suspended Solids (TSS) and lead levels to well below the plant’s required discharge limits at high 800 gfd flux rates. In addition, these units routinely achieved >50% solids dry cakes that could be disposed of in a RCRA-approved landfill (at significant cost savings compared to the concentrate from the crossflow microfilters). Subsequent evaluation of the Profix filter aid/stabilization agent per the SITE technology actually improved flux and resulted in stabilized cakes (passed TCLP).

ELECTRONICS MANUFACTURING PLANT WASTEWATER WITH OBERLIN FILTER TECHNOLOGY

Property                   Raw Wastewater      Oberlin Filter      Discharge Limits**

Turbidity (NTU)

TSS (ppm)

Lead (ppm)

Barium (ppm)

Cadmium (ppm)

Capacity (gpd)

Flux (gfd)

Cake % Solids

Cakes Pass TCLP?

>1,000

1,000

20

25

2

2,500

---

---

No

NR

26

1.0

NR

NR

---

---

---

Must pass

0.3

<1

0.04

<1**

<0.05**

4,500

800

54

Yes

** Detection Limit

Clarifier Underflow Heavy Metals Removal

This plant was faced with a land ban of their main clarifier metal hydroxide underfiow sludge (2-3% solids) because it did not pass the EPA “Paint Filter Test” 11• This clarifier treated the entire plant effluent and removed primarily lead, zinc, and copper. To satisfy the RCRA land ban resthctions, the plant hired mobile dewaterer who used a manual, recessed-chamber filter press that produced sloppy cakes. These cakes had to be shovelled into dumpsters for off-site disposal. The Oberlin Filter technology was installed replacing the mobile dewaterer. As the below table shows excellent effluent quality at very high, 10,000 gpd capacity and 900 gfd flux. The cakes were sufficiently dry (50% solids vs. 40% requirement) to pass the “Paint Filter Test” and were acceptable to the hauler/landfill operator at a significant cost saving to the plant. The Oberlin Filter system operates automatically at significant labor savings compared to the manual press. Profix has been evaluated here and was implemented recently since the resultant cakes pass TCLP particularly for lead. As a result, off site disposal costs were reduced about $200M annually.

CLARIFIER UNDERFLOW HEAVY METALS REMOVAL WITH OBERLIN FILTER TECHNOLOGY

Property                   Raw Wastewater      Oberlin Filter      Discharge Limits**

Turbidity (NTU)

TSS (ppm)

Lead (ppm)

Zinc (ppm)

Copper (ppm)

Capacity (gpd)

Flux (gfd)

Cake % Solids

Cakes Pass TCLP?

>1,000

17,000

40

410

1,050

6,800

---

---

No

NR

20

5.0

5.0

5.0

---

---

40

Must pass

1.0

2.5

< 0.01

0.2

1.2

10,000

900

50

Yes

Heavy Metals Removal from Chemical Plant Wastewater

This plant was faced with severe heavy metal discharge restrictions based on recent EPA chronic toxicity regulations (ie, 15 ppb Cu, 60 ppb Pb, 130 ppb Ni, 150 ppb Cr, and 300 ppb Zn). In addition, this mixed heavy metals waste had to be stabilized to meet the “third-third” EPA BDAT (Best Demonstrated Available Technology) regulations for land disposal. Ion exchange was first evaluated, but it could not meet the low ppb limits for all the metals and its regenerant required off-site stabilization at high cost. As a result, the Oberlin Filter technology was next evaluated since it could produce dry, stabilized cakes.  An extensive pilot testing program was conducted and finally, it was demonstrated that these limits could be achieved quite routinely. In addition, these low metals limits were obtained at a very high 3600 gfd flux; and the resultant “dry” cakes passed the TCLP test for all eight toxic metals (per EPA “thirdthird” regulations issued. As a consequence, the Oberlin Filter technology was selected and operating successfully.

HEAVY METALS REMOVAL FROM CHEMICAL PLANT WASTEWATER WITH OBERLIN FILTER TECHNOLOGY

Property                   Raw Wastewater      Oberlin Filter      Discharge Limits**

Turbidity (NTU)

TSS (ppm)

Copper (ppb)

Lead (ppb)

Zinc (ppb)

Nickel (ppb)

Chromium (ppb)

Capacity (gpd)

Flux (gfd)

Cakes Pass TCLP?

>100

100

2,000

100

3,500

400

1,000

75,000

---

No

<0.2

< 1

15

60

250

130

150

---

---

Must pass

0.06

<0.2

< 5

<5*

<10*

<5 *

< 100*

130,000

Yes

Wastewater Mixed Metals Removal

This plant required stringent heavy metals removal to meet chronic aquatic toxicity criteria. A variety of technologies were evaluated, but the Oberlin Microfiltration technology provided the best overall metals removal of this waste as most removed to below detection limits. The resultant cakes passed the TCLP, which was also a big factor since other technologies required additional post-treatment to produce stabilized solids.

 

MIXED WASTEWATER METALS REMOVAL WITH OBERLIN FILTER TECHNOLOGY

Property                   Raw Wastewater      Oberlin Filter      Discharge Limits**

Turbidity (NTU)

TSS (ppm)

Fe (ppm)

Cr (ppb)

Cu (ppb)

Zn (ppb)

Cake % Solids

Flux (gfd)

Cakes Pass TCLP?

<1000

1200

80

1800

1000

14,000

---

---

No

NR

20

NR

150

15

250

---

---

Must Pass

0.2

0.4

<0.1*

50

<5*

<10*

51

400

Yes

*      Detection limit

**    Based on EPA Chronic Toxicity Tests..

NR= Not Regualted

Explosives Plant Lead Removal from Wastewater 

This plant had sent their Pb wastewater off-site for treatment and stabilization at considerable expense. They heard of the Oberlin Filter technology and evaluations in the below table demonstrated complete feasibility as Pb was removed to well below the proposed discharge limits and cakes passed TCLP at a reasonably high 2000 gfd flux. As a consequence, the Oberlin Filter was installed.

WASTEWATER LEAD REMOVAL FROM EXPLOSIVES PLANT WITH OBERLIN FILTER TECHNOLOGY

Property                   Raw Wastewater      Oberlin Filter      Discharge Limits**

---

<20

5

---

Must Pass

<1

<1

0.3

2000

Yes

Turbidity (NTU)

TSS (ppm)

Pb (ppm)

Flux (gfd)

Cakes Pass TCLP?

9000

3300

110

---

No

Chelated Wastewater Copper Removal from Wastewater

This plant had two wastewater streams which required Cu removal to meet the 50 ppb toxic discharge limit as well as to protect the on-site biological waste treatment system. One stream contained chelated Cu (Case II) while the other was chelated as well as heavily contaminated with organics (Case II). Ion exchange and oxidation with iron were tried on Case I stream with little success while hot sodium sulfide precipitation was successfully demonstrated for Case II after the organics were removed. However, it was later found that complete organics removal could not be assured so the Oberlin Filter technology was evaluated on both streams. The below table shows that Cu removal to 10 ppb was obtained at high 4200 gfd flux (Case I) and <200 ppb Cu at 300 gfd flux for Case II. The higher — 200 ppb Cu in Case II was due to the copious — 50% organics present, but combined waste discharge was below 50 ppb. In addition both cakes passed TCLP and even organics were stabilized when a mixed Profix/organic stabilizer (FOl) was used. Economics showed that Case I treatment costs amounted to low $ 1.60/1000 gallons while Case II about $130/1000 gallons, but Case II disposal cost savings amounted to about $1350/1000 gallons due to the high level of organics present that could be recovered and recycled. As a consequence, the Oberlin Filter was installed for the treatment process.

WASTEWATER COPPER REMOVAL WITH WITH OBERLIN FILTER TECHNOLOGY

Property                   Raw Wastewater      Oberlin Filter      Discharge Limits**

20

25

500

2,500

---

No

 

 

>1000

30,000

1600

---

NO

~10%

1. Chelated Case:

   Turbidity (NTU)

   TSS (ppm)

   Fe (ppb)

   Cu(ppb)

   Flux (gfd)

   Cakes pass TCLP?

 

2. Organics Case:

   Turbidity (NTU)

   TSS (ppm)

   Cu(ppm)

   Flux (gfd)

   Cakes pass TCLP?

  Organics Recovery

  (Vol %)

---

---

---

50

---

Must Pass

 

 

---

---

0.2

---

Must Pass

Cannot Discharge

<0.3

<0.2

20

4200

Yes

 

 

 

<10

2

<0.2

300

Yes

98.6%

Wastewater Cleanup - Barium, Titanium, Neodymium, Bismuth and Lead

Sun Valley, California - This facilities manufacturing process produces two liquid waste streams containing a complex array of metal oxides and titanates. Elements with the highest concentration are barium, titanium, neodymium, bismuth and lead. The compositions of the two waste steams had lead and total suspended solids level typically range from 0.5 to 5.0 percent. The treatment objective was to reduce concentration of metals to meet to satisfy the Los Angeles sewer effluent limits of 5.0 ppm for soluble lead and 26.0 ppm total suspended solids. The effluent characteristics from the Oberlin microfiltration system were 0.2 to 0.4 ppm soluble lead and 5ppm total suspended solids. Well below the requirements of the Los Angeles sewer effluent limits with very low maintenance costs.

 
Cleaning Wastewater Slurry of Lead and Suspended Solids

Manati, Puerto Rico - Operations at the facility produce a wastewater slurry that contains 1,000-5,000 parts per million(ppm) of suspended calcinated or partly fused, high-lead content glass material and 2,000 to 10,000 ppm of total suspended solids. The objective of the facility was to have a filtration system that removed suspended particulates from the wastewater slurry ranging from .5 to 30 microns in size. The Oberlin microfiltration system removed nearly all particles from .5 to 30 microns in size.

 
Low Level Radioactive Water

Zinc, Lead, Aluminum, Copper and Uranium particles.  Levels of metals reduced to <0.1 ppm. Uranium levels reduced to <0.01 ppm.  Limits are 0.5 ppm.

 

Copper, Lead & Zinc Removal

Battery manufacturer wastewater removal of copper, lead and zinc. OFC reduce levels from as low as 400 ppm to as high >1000ppm to < 1ppm.  Lead <0.01 ppm.

 

Cadmium Sulfide

Solydra, California: Toxic metal removal –Sludge dewatering

 

Lead Removal
Explosives manufacturer lead containing wastewater treated and filtered removing lead from 110 ppm in feed to 0.3 ppm in clean discharge. Discharge limits were 5 ppm.

 

Cadmium and Tellurium

First Solar- Global: Remove glass fines from toxic metals recovery (cadmium and tellurium).  Feed water solids concentration was >300,000 mg/l.  Clean water quality discharged <26 mg/l