Project Summary

United States

Environmental Protection

Agency

Field Testing and Evaluation of

Zerpol® Technology at Pioneer

Metal Finishing

Hanna J. Saqa, Daniel J. Watts, Mohammed Elsaady, and Johnny Springer

National Risk Management

Research Laboratory

Cincinnati, OH 45268

Research and Development

The U.S. Environmental Protection

Agency’s Waste Reduction Innovative

Technology Evaluation (WRITE) Program has an objective of evaluating

technologies that have potential for

waste reduction or pollution prevention as compared with other currently

used approaches. The Zerpol1 process,

as used in metal plating operations,

captures all aqueous effluent from the

manufacturing operations, conditions

the effluent to remove any metal or

cyanide that may be present, and permits the reuse of the conditioned water

in rinsing operations. About 30% of the

recovered water is fed into the plant

boiler to generate distilled water for

critical rinsing. The goals of this study

were to confirm that the quality of the

water derived from the Zerpol process

is appropriate for the intended reuse,

and that the process is safe, and to

estimate the economics of the installation and use of the process as compared to other alternatives.

The evaluation was carried out at Pioneer Metal Finishing in Franklinville,

NJ. Field observations and sample collection were carried out over a 1-mo

period. Based on the observations,

which included determination of the

content of metals and solids at selected

sampling points throughout the system, it is concluded that for facilities

similar to those where the evaluation

was conducted, the Zerpol system provides significant advantages and is insensitive to fluctuations caused by

acidic or basic bath dumps into the

system. At Pioneer, approximately 80%

of the process water is reclaimed and

recirculated. Estimation of the economics suggests that the incremental cost

of about $120,000 for a 2000 gal/day

Zerpol system results in savings in

chemical usage, labor and maintenance,

and waste disposal costs providing a

payback period of 5.3 yr. While the system eliminates effluent discharges at

the site, it does produce a metal sludge

stream that facilitates metal recovery

through smelting, and a high solids

content stream from boiler blowdown.

The system eliminates the use of chlorine for cyanide destruction, eliminating that source of chlororganic

materials emitted from the site.

This Project Summary was developed

by EPA’s National Risk Management

Research Laboratory, Cincinnati, OH,

to announce key findings of the research project that is fully documented

in a separate report of the same title

(see Project Report ordering information at back).

Introduction

The Waste Reduction Innovative Technology Evaluation (WRITE) program had

an objective of identifying and evaluating

technologies with potential for waste reduction or pollution prevention as compared with other currently used

technologies. The Zerpol process, as applied to waste waters from metal finishing

operations, has that potential based upon

EPA/600/SR-95/126 August 1995

1 Mention of trade names or commercial products does

not constitute endorsement or recommendation for

use.
2

claims and reports of its performance. The

process involves the capture of all aqueous effluent from the manufacturing operation, conditioning of this effluent to

remove any metals or cyanide that may

be present from rinsing procedures, and

the reuse of the recovered water for rinsing. About 30% of the recovered water is

fed into a boiler to produce distilled water

for critical rinsing. Boiler blowdown maintains the salt level in the recirculated water at a level acceptable to the metal

finishing process. Thus, the use of the

Zerpol process has the objective of permitting continued recycling and reuse of

water in the manufacturing process. System water loss due to boiler blowdown

and evaporation from the process tanks is

made up by fresh water supply.

The Zerpol process does produce at

least two waste streams, a metal hydroxide concentrate that results from the conditioning of the process effluent (suitable

as a resource for metal recovery by smelting or similar operations) and blowdown

from the boiler (a concentrated solution of

soluble salts). In some instances, waste

oil may accumulate at the surface of the

effluent storage tanks. This oil is skimmed

and disposed of as waste.

A previous EPA-supported study by researchers at the University of Central

Florida [2] evaluated the effectiveness of

the Zerpol process as a waste management technique for the metal finishing industry. That study concluded that there

were potential applications for the process in certain segments of the metal

finishing industry. However, the report

raised some questions that could not be

answered based on the evaluation that

was carried out then. These questions

included uncertainties regarding rinse water quality, boiler economics and operation, product quality, and safety.

The purpose of this project was to confirm and extend the previous study of the

Zerpol process to provide information

about its waste reduction potential, operational implications, safety issues, and economics.

The evaluation was carried out at Pioneer Metal Finishing, Inc. in Franklinville.

At the time of the study the facility operated one shift per day, five days per week.

Pioneer Metal plates a variety of metal

objects, emphasizing copper, nickel, and

chromium plating operations. All parts are

rack plated. All parts are cleaned, acid

dipped, copper plated and nickel plated.

Forty percent receive chrome. The base

metals that are plated are steel, brass or

zinc diecast. Components for electric

equipment, automobile parts, and refrigeration and plumbing parts make up 80%

of the work load.

During the field evaluation period of

about one month, the shop was producing

approximately 3,000ft2

 of plated surface

per shift. The parts varied from small

screws up to items with 0.8ft2 of surface

each. The plating lines and the Zerpol

system are shown schematically in Figures 1 and 2.

The Zerpol system has been in place at

the facility since 1981. This technology

allows the conditioning and reuse of process water. The Zerpol technology could

be useful not only for the metal finishing

industry, but also for many types of waterusing industrial operations. In this system,

aqueous effluent is accumulated in processing tanks to allow conditioning in a

batch mode. In the metal finishing application, conditioning is a step-wise process.

Initially, an active oxygen compound,

reported to be hydrogen peroxide [1], is

added, as needed, to oxidize cyanide ions.

(Although possible compositions of the

active oxygen compound and the reducing agent are reported in the literature,

Zerpol Corporation indicates that the nature of these formulations is proprietary

information. Therefore, during this investigation, no effort was made to determine

their exact compositions). This step is followed by the addition of a reducing agent,

reported to be sodium hydrosulfide [1], to

reduce chromium, if present. Sodium hydroxide is added for pH adjustment to

induce precipitation of metals.

After a 2- to 3-day settling period, the

clarified water is transferred to a storage

tank and used in the shop process as

needed. Approximately two-thirds of the

recovered water is used in the process for

non-critical rinsing and about one-third is

directed to the boiler. The steam generated is used for heating process baths.

The condensate is used in the plating

process for critical rinsing and partially for

boiler feed to reduce solids build up in the

boiler. The net effect is the near total

reuse of the effluent stream, thus attaining a zero discharge condition at the location.

The dissolved solids in the clarified recycled water are kept within acceptable

limits by controlling the boiler blowdown.

The residual solids streams generated from

the precipitation process and from the

boiler blowdown are sent off site for reuse

or disposal. The metal contents are reclaimed by smelting.

Because effluent conditioning is done in

a batch mode, one tank at a time, adequate tank volumes are required for collection of the raw wastewater and for storage of the clarified effluent prior to reuse.

The frequency of batch conditioning at

Pioneer is dependent upon production

schedules; initially it averaged about once

every five days or approximately five times

per month. The capacity of each of the

two effluent processing tanks is 25,000

gal compared to a reported design process usage rate of about 5,000 gal/day.

The (clarified) water storage tank holds

50,000 gal. Over the last few years, the

process flow rate has been greatly reduced. At the time of the study, it was

less than 2,000 gal/day.

Due to the large holding capacities of

the tanks, the Zerpol system can handle

process dumps such as caustic, acid, and

other cleaners without noticeable detrimental effects. Some processes may need

de-ionized water for the most critical rinsing, in addition to the use of the condensate produced from the boiler. This

condensate is controlled to have a TDS of

less than 1000 mg/l. Condensates with

higher dissolved solids contents are automatically switched over to the clarified

water storage tank.

Two principal concerns associated with

the process relate to the successful operation of a boiler with an input TDS of

over 5000 mg/l, and whether the produced

condensate is satisfactory for critical rinsing requirements and for acceptable product quality in the plating operation. A

sufficient demand for steam will help justify the energy input for the operation of

the boiler. Water conservation and flow

reduction are also key factors in the success of the system.

System Performance

Evaluation Data

Several specific sets of field data were

collected at the facility to measure and

describe the performance of the Zerpol

process and to define more closely its

areas of applicability. Analysis of the collected data addresses the following five

topics: 1) Whether the quality of the recirculated water is appropriate to maintain

the plating process effectively and efficiently; 2) Whether the Zerpol process

yields a metal concentrate that can be

used for metal recovery through smelting

or other standard metal recovery technology; 3) Whether unsafe levels of hydrogen cyanide form within the Zerpol system;

4) Whether the use of a boiler to maintain

an acceptable TDS level in the recirculated water is a sound, practical and economically feasible alternative; 5) Whether

the economics of the installation and operation of the Zerpol system are favor-
3

Figure 1. Schematic of plating system.

FLOW OF WORKPIECE

Clarified Water to Rinses

Condensate to Rinses

Zn

Diecast

Soak

Steel

Soak

(caustic)

Rinse

Diecast

Electroclean

(caustic)

Steel

Electroclean

(caustic)

Rinse Rinse Rinse H2SO4

2%

HCI

75%

Steam to Tank Heaters

Effluent from Plating Tanks and Rinses

Condensate from Tank Heaters

Condensate to Rinses

Clarified Water to Rinses

Effluent from Plating Tanks and Rinses

Rinse Rinse Rinse Rinse Rinse Rinse Rinse Rinse

Cu/CN

Plating

(2 Tanks)

Cu/CN

Strike

Rinse

H2SO4

0.5%

Ni

Plating

(4 Tanks,

acidic)

Ni

Reclaim

Trivalent

Chrome

Plating

D.I.

Rinse

Steam to Tank Heaters

Effluent from Plating Tanks and Rinses

Condensate from Tank Heaters

Condensate from Tank Heaters

Clarified Water to Rinse

Steam to Tank Heaters

Condensate to Rinses

ZERPOL SYSTEM

Effluent from Plating Tanks and Rinses
4

Figure 2. Schematic of Zerpol system - basic process flow diagram.

PLATING LINE

Condensate (Auto Condensate

< 1000 TDS Switchover) > 1000 TDS

Condensate from Tank Heaters

Clarified Water to Rinses

Steam to Tank Heaters

Condensate to Rinses

Condensate

Tank

1,500 gal

Cond.

Tank

Steam

Stack

Gases

NaOH for pH (4 oz.)

Sodium Dichromate (400ml)

Potassium Cyanide (450 ml)

Propr. Defoamer (500 ml) Water Tube Boiler 60 HP 2.5 • 106

Btu/hr

Boiler

Feed

Tank

Boiler

Blowdown

Tank

Salt

Concentrator

2,000gal

40% Solids

Off-site Disposal

to DuPont

(1990:22,500 gal/yr)

Make-up

water

Design

Flowrate

≈ 5,000 gal/d

CLARIFIED WATER STORAGE

50,000 gal

EFFLUENT PROCESSING

TANK "A"

25,000 gal

presently: max. 25 days

retention

EFFLUENT PROCESSING

TANK "B"

25,000 gal

presently: max. 25 days

retention

Sludge

Effluent from

Plating Tanks

and Rinses

Mixing

Tank

700 gal

Metals

Concentrator

11,000gal

2-6 Months Storage

0.25%->10% Solids

Off-site

Treatment

and Metal

Reclamation

(1990: approx.

7,500 gal/yr)

...SAMPLING POINTS S-n

S-5

S-3

S-1

S-2

S-4

S-9

S-10

S-6

S-7

S-8

• Adjust ph with NaOH to precipitate metals

• Use Sodium Hydrosulfite to reduce Cr- +6to Cr3-

• Use H2O2 to oxidize Cyanide

Chemicals

Feed Tank

75 gal
5

able, particularly in comparison with the

costs of using other waste management

options.

Field Sampling and Operating

Data Gathering

Three types of data were gathered during six-day tests conducted over a 32-day

period: 1) Composite stream samples for

chemical analysis; 2) Actual flow rate measurements of the generated effluent, recirculated water, steam condensate and

boiler fuel gas; 3) Historical operating and

maintenance data on the present Zerpol

System and the system that preceded it,

a system that involved precipitation of

metal sludges and discharge of the treated

aqueous effluent.

For each test, composite samples of

the process and of the Zerpol streams

were taken. System flow rates, namely

process effluent flow, and the pumping

rates of clarified water and of the sludge

were measured by capturing the flow in a

container and by timing the flow with a

stop watch. The boiler feed was measured by an actual water meter.

Samples were taken from ten sampling

points and analyzed for cyanide ions, calcium, magnesium, copper, nickel, chromium, iron, zinc, cadmium, phosphorus,

total solids, total suspended solids, total

dissolved solids, and pH.

The analytical data and volume flow

measurements are used to determine

mass loading entering and leaving the

Zerpol system, and by difference, the

amount captured by the Zerpol system.

Similarly, the quality of the condensate

was determined, as well as the composition of the boiler blowdown. The boiler

operation was monitored during five working shifts. The total volume of water fed

into the boiler was metered. The volume

of boiler blowdown was determined by

metering and by calculations. Composite

samples were analyzed.

Because concern was expressed in the

previous study about levels of hydrogen

cyanide potentially produced in the Zerpol

process, air samples were taken, using

OSHA standard procedures, at the first

point open to the atmosphere after mixing

of acid streams and cyanide ion bearing

streams. These air samples were taken at

the mixing tank ahead of the first holding

tank, where analytical measurements of

the pH and cyanide content of the water

have also been made. Air samples were

analyzed for hydrogen cyanide.

Because Pioneer claims that the Zerpol

process continues to operate well even

when process baths are dumped, samples

and measurements were taken before and

after the occurrence of these extreme conditions to demonstrate whether heavier

inorganic loadings interfere with the quality of the recirculating water.

To address the issue of potential problems with foaming in the boiler that were

raised in the previous report on the process, the feed water to the boiler was

sampled before and after addition of the

defoaming agent and evaluated according

to the Standard Test Method for Foam in

Aqueous Media (Bottle Test), ASTM

D3601-88.

It should be noted that Pioneer frequently reported discharge violations while

the former continuous discharge treatment

system was in operation from 1975 to

1981. These violations were a primary

reason the previous treatment system was

replaced and there have been no such

incidents since the Zerpol system became

operational.

Since the mid-eighties, shop management has substantially reduced the total

use of water from the previous 5,000 gal/

day to less than 2,000 gal/day. Waste

minimization initiatives such as the reuse

of dragouts, have been very effective.

While the previous system required relatively large volumes of water for most

effective operation, the Zerpol system uses

substantially reduced water volumes and

has encouraged and justified additional

pollution prevention efforts. In 1989, the

shop operation switched from two per day

to one shift starting at 6:00 AM and ending at 2:30 P.M.

The operation of the Zerpol system and

the boiler were fine tuned to match the

requirements of the plating process. The

25,000-gal effluent processing tank that

used to hold the effluent for five work

days now holds effluent for about 18-20

work days. This means that the quantity

of chemicals used to precipitate the metal

hydroxides in the effluent processing tanks

has been greatly reduced.

The boiler serves two purposes: It provides 10-psig steam to heat the plating

baths. The condensate is used as a source

for rinsing and for boiler feed water whenever excess condensate is available. It is

also a means of controlling the level of

solids in the recirculated process water.

The solids are removed from the system

through boiler blowdown. For this applicaTable 1. Summary of Process Streams Chemical Analyses for Metals and Solids

Sample S-2 S-3 S-4 S-5 Boiler Boiler Feed S-7 S-8 S-9 Waste Mtl.

Point Effluent Effluent Clarified Sludge Feed (S-6) (S-6) Boiler Steam Make Up In Sludge

Tank Processing Water Tank Clarified Condensate Blowdown Condensate 1,000 Sq. Ft.

Inlet Tanks Tank Inlet Inlet Water Return Plated Area

[mg/l] [mg/l] [mg/l] [mg/l] [mg/l] [mg/l] [mg/l] [mg/l] [mg/l] [lb/1000ft2]

Material

Analyzed

CN 16.63 36.1 2.69 245 2.18 3.21 18.53 0.814 < 0.01 —-

TDS 9820 7820 8380 8620 8329 725 85146 57.2 60 —-

Ca 19.24 13.94 22.9 137 16.94 <8.81 74.1 <8.09 <8.09 0.058

Mg 0.99 0.57 0.73 11.2 0.9 <0.095 1.25 <0.08 0.982 0.0047

Cd 0.26 <0.003 <0.003 <0.235 <0.003 <0.008 <0.008 <0.008 <0.003 0.000099

Cr 22.23 42.14 2 538 1.7 23.36 236 0.12 <0.046 0.23

Cu 11.17 27.89 2.9 445 1.32 0.24 10.08 0.16 <0.02 0.19

Fe 22.22 48.68 2.01 723 2.05 0.47 5.65 0.28 4.99 0.30

Ni 71.86 201 10.1 3628 28.26 3.73 52.57 <1.25 <1.25 1.53

Zn 27.83 84.35 0.92 1434 0.76 0.16 2.3 0.12 0.08 0.60

P 24.91 19.19 <4.69 189 <4.86 <4.69 9.62 <5.98 <4.69 —-

CN in air at Process Effluent Tank: 0.058 mg/m3.

CN in air at Boiler Blowdown Sump Surface: 0.101 mg/m3.
6

tion, the boiler capacity and blowdown

frequency are sufficient to keep the total

dissolved solids in the recirculated water

at less than 10,000 ppm.

Summary of the Results

Table 1 shows that the average TDS of

the clarified recirculated process water is

about 10,000 ppm; of the steam condensate is about 500 ppm; of the boiler

blowdown is 100,000 ppm. This table also

shows that the metals concentration of

the recirculated water is higher than what

is allowed for discharge into a typical

POTW, e.g. Ni is 10.1 ppm compared

with an allowable limit of 3.98 ppm. The

cyanide concentration is 2.69 ppm compared with the limit of 1.20 ppm. Treatment to levels within the allowable limit

may be possible, but at much higher cost,

may not be economically attractive. The

observed levels are routinely maintained

by Pioneer because they are economically achievable and do not negatively affect their processes.

Table 2 shows that the clarified water

recirculation rate is about 1,700 gal/day.

This is much lower than the initial system

design rate of 5,000 gal/day. Effluent flow

rate is in the range of 3.36-3.82 gpm.

About 37% of the recirculated water is

diverted through the boiler. Boiler

blowdown averages about 0.20 gpm. The

boiler generates steam to the process at

an average condensate equivalent rate of

1.35 gpm. Average heat delivery to the

process from the steam is about 6.55 x

105

 Btu/hr. Boiler thermal efficiency based

upon heat delivered to process compared

to heat energy input to boiler is about 39-

40%. The daily energy cost to run the

boiler is in the range of $104-127/day.

Table 3 shows that the operating cost

of the Zerpol system is about 1/3 that of

the previous system, however; the installed

cost of the Zerpol is nearly two times that

of the previous system.

Conclusions

The Zerpol zero discharge system can

be used successfully at metal finishing

Table 2. Operating Data of the Zerpol Effluent Processing System

Test Series 1 1 1 2 2 Five

Date 4/14/92 4/15/92 4/16/92 5/14/92 5/15/92 Day

Test Number 1 2 3 1 2 Average

Clarified Water

Total Flow/24 hr: 1747.4 gal 1592 gal 1705 gal 1686 gal 1721 gal 1690.3 gal

Flow During Daytime 1079.4 gal 949.2 gal 1058 gal 1096 gal 1088 gal 1054.1 gal

to Process:

 (Average Flowrate) (2.57 gal/min) (2.26 gal/min) (2.52 gal/min) (2.61 gal/min) (2.59 gal/min) (2.51 gal/min)

* Flow During Night 668 gal 642.6 gal 647 gal 590 gal 633 gal 636.1 gal

to Boiler:

(Average Flowrate) (1.59 gal/min) (1.53 gal/min) (1.54 gal/min) (1.40 gal/min) (1.51 gal/min) (1.51 gal/min)

 % of Clarified Water 38% 40% 38% 35% 36.8% 37.6%

Passing through Boiler:

Boiler Blowdowns

Average Flowrate: 0.28 gal/min 0.14 gal/min 0.13 gal/min 0.19 gal/min 0.28 gal/min 0.20 gal/min

No Blwdns.-Minutes 3/1min/39.2gal 2/1min/29.4gal 2/1min/27gal 2/1min/40gal 3/1min/40gal 2.4/1min/35gal

Ea.-Gal Ea. During

Daytime:

During Nighttime:0 0/0/0 0/0/0 0/0/0 0/0/0 0/0/0 0/0/0

Steam from Boiler (as Condensate)

During Daytime to 1.18 gal/min 1.26 gal/min 1.28 gal/min 1.16 gal/min 1.04 gal/min 1.18 gal/min

Process:

Nighttime to Storage Tank: 1.59 gal/min 1.53 gal/min 1.54 gal/min 1.40 gal/min 1.51 gal/min 1.51 gal/min

Average Flowrate (24 hr.): 1.385 gal/min 1.395 gal/min 1.41 gal/min 1.28 gal/min 1.275 gal/min 1.35 gal/min

Average Heat in Steam 6.72 *105 Btu/hr 6.77 *105 Btu/hr 6.84 *105 Btu/hr 6.22 *105 Btu/hr 6.19 *105 Btu/hr 6.55 *105 Btu/hr

Flow to the Process:

Condensate

Flow During Daytime to 549.9 gal 586.8 gal 593 gal 509 gal 515 gal 550.7 gal

Process as Rinse Water:

(Average Flowrate) (1.31 gal/min) (1.40gal/min) (1.41 gal/min) (1.21 gal/min) (1.23 gal/min) (1.30 gal/min)

*Flow During Daytime 614.1 gal 584.8 gal 592 gal 566 gal 556 gal 582.6 gal

to Boiler:

(Average Flowrate) (1.46 gal/min) (1.40 gal/min) (1.41 gal/min) (1.35 gal/min) (1.32 gal/min) (1.40 gal/min)

Boiler Data

Type-yr in Service-Measured Eff.: Columbia WL 180 - 3 yr in service - 67% to 68%

(continued)
7

Table 2. Continued

Test Series 1 1 1 2 2 Five

Date 4/14/92 4/15/92 4/16/92 5/14/92 5/15/92 Day

Test Number 1 2 3 1 2 Average

Boiler Thermal Efficiency: 39%-41% 38%-40% 38%-40% 42%-44% 42%-44% 40%-42%

(Btu/hr to Process Btu/hr

to Boiler)

Average Energy Input 17.1*105 17.7*105 17.7*105 14.6*105 14.6*105 16.3*105

to Boiler:(Btu/hr)

Daily Boiler Energy $127 $127 $127 $104.7 $104.7 $118.1

Costbased upon

$0.53 / 105 Btu:

Average Effluent Flowrate During Single Tank Filling Period of 25 Days Containing 18 Workdays @ 7 Hours: 3.00 gal/min.

Average Effluent Flowrate During First 3 Test Days (Excluding Bath Dumps): 3.36 gal/min.

Average Effluent Flowrate During First 3 Test Days (Including Bath Dumps): 3.32 gal/min.

Total Effluent Flow During Single Tank Filling Period of 25 Days Containing 18 Workdays @ 7 Hours: 22,700 gal.

Clarified Water Produced During the 25-Day Period: 19,700 gal Sludge Produced During the 25-Day Period: **3,000 gal.

* Boiler feed: during daytime - condensate; during nighttime - clarified water Boiler Feed Water Treatment Done Once a Day at 2 p.m.

** 99% Water. Water Removed after Settling.

Table 3. Comparison of Installation and Operating Cost Data of the Past and Present Treatment Systems at Pioneer

 Previous System Present Zerpol System(1)

Equipment Individual Treatment Tanks Storage Tanks and Boiler

Chemicals, $/yr2) 12,300 - 15,300 2,700 - 3,300

Labor, Repair, Maintenance & Monitoring3) 35,140 1,890

Sludge + Salts Disposal, $/yr not available 8,800

Total Operating Costs4), $/yr 47,440 - 50,440 13,390 - 13,9905)

Installed Costs, $ 65,000 (1975) 170,000 (1981)

D.I. system, Installed Cost, $ 30,000 30,000

Flow, gal/day 16,000 - 40,000 1,500 - 5,000

Operation, day/yr 250 250

Years in service 1975 - 1981 1981 to present

Original flow, gal/day 40,0006) 5,000

Boiler energy cost (not included) (not included)

1) Requires Deionized (D.I.) Water System.

2) Includes Chemicals for Boiler and D.I. Water System.

3) Based on Labor Costs of $17.5/hr Includes labor for D.I. Columns Backwash.

4) Costs of Chemicals, Operating Labor, Repair, Maintenance, and Monitoring.

5) Includes Disposal of Sludge and Salts.

6) The Previous System Could Only Function With Diluted Flow, Requiring Large Volumes of Water.

shops where the treated effluent and the

generated condensate can be recirculated

and reused for rinsing without impairing

product quality.

The Zerpol system works well for the

Pioneer metal finishing process which was

the subject of the one- month field evaluation. During that period, acid and caustic

baths were intentionally dumped into the

system as part of the normal operation of

the facility. This did not result in any noticeable product quality impairment. This

system should perform just as well for

shops with similar production and quality

requirements.

Because the entire effluent is captured

and collected in large capacity tanks prior

to recycling; 1) risk of accidental release

is reduced; 2) special operating permits

are not required, although local agencies

should also be consulted; 3) compliance

with effluent pretreatment standards is not

required; 4) timing of chemical addition

and processing is flexible; and 5) maintenance emergencies are less frequent and

more easily managed than with other

waste management options. Also, there

seem to be no acute safety concerns.

Measured levels of hydrogen cyanide at

the effluent mixing tank and at the boiler

blowdown sump were extremely low, well

within the OSHA standards.

When the required equipment for the

zero discharge system is identified, its economics and pollution reduction potential

should be compared with those of other

systems, such as:

• Zero discharge, low temperature

evaporative recovery and treatment

systems.

• Non-chemical wastewater treatment

system.

• Carbon absorption.

• Microfiltration, Ultrafiltration, Reverse

Osmosis.

• Ion Exchange.

• Electrowinning by itself or in combination with other treatment systems.

It should be noted that while it is true

that the Zerpol zero discharge system does
8

Official Business

Penalty for Private Use

$300

EPA/600/SR-95/126

not contribute to pollution at the site, this

does not mean that its recovered materials do not contribute pollution to the environment at the smelting facility. Identifying

and quantifying this pollution could not be

accomplished in this study because of the

reluctance of the smelting operation to

provide information, but should be considered in any life-cycle analysis of this and

related processes.

The results of this investigation demonstrate that, at this facility, the Zerpol zero

discharge system eliminates the discharge

of an aqueous wastestream by allowing

recycling of most of the process water.

The system facilitates the removal of metals in a form that is suitable for metal

recovery. Salts from the boiler blowdown

are treated as wastes in a standard water

treatment facility. These positive factors

represent a reduction in the volume of

waste generated at the facility through a

series of process modifications and have

encouraged and facilitated source reduction initiatives at the facility.

The full report was submitted in fulfillment of Assistance Agreement No. CR816142 by New Jersey Department of

Environmental Protection under the sponsorship of the U.S. Environmental Protection Agency.

Hanna J. Saqa and Daniel J. Watts are with New Jersey Institute of Technology, Newark, NJ 07102; Mohammed Elsaady is with the New Jersey

Department of Environmental Protection and Energy, Trenton, NJ 08625;

and the EPA author, Johnny Springer (also the EPA Project Officer, see

below) is with the National Risk Management Research Laboratory, Cincinnati, OH 45268.

The complete report, entitled "Field Testing and Evaluation of Zerpol® Technology at Pioneer Metal Finishing," (Order No. PB95-260 238; Cost: $19.50,

subject to change) will be available only from:

National Technical Information Service

5285 Port Royal Road

Springfield, VA 22161

Telephone: 703-487-4650

The EPA Project Officer can be contacted at:

National Risk Management Research Laboratory

U.S. Environmental Protection Agency

Cincinnati, OH 45268

United States

Environmental Protection Agency

National Risk Management Research Laboratory (G-72)

Cincinnati, OH 45268

BULK RATE

POSTAGE & FEES PAID

EPA

PERMIT No. G-35