APPROACHING ZERO DISCHARGE DEMONSTRATION PROGRAM Pilot Scale Polymer Filtration for Zinc Metal Recovery and Wastewater Reuse

Prepared by:

PolyIonix Separation Technologies, Inc. Dayton, NJ 08810-1004 A.G. Bricker K.M. Kraus S.M. Kim

Edited by:

CAMP, Inc. Cleveland, OH 44103-4314 A. Gus Eskamani Karrie Jethrow

Host Company:

Pottstown Plating Works, Inc. Pottstown, PA 19646 John C. Welkie, Environmental Director

Notice

i The U.S. Environmental Protection Agency through its Office of Research and Development funded the research described here under IAG DW13937782-01 to the National Institute of Standards & Technology (NIST). Mention of trade names or commercial products does not constitute endorsement or recommendation for use.

ii TABLE OF CONTENTS 1. EXECUTIVE SUMMMARY...... 5

1.1. HISTORY...... 5 1.2. GOAL/APPROACH...... 5 1.3. RESULTS...... 6 1.4. CONCLUSION...... 6 1.5. AZD PEER PANEL COMMENTS...... 7

2. INTRODUCTION...... 7

2.1. BACKGROUND...... 8 2.2. PURPOSE...... 9 2.3. DEMONSTRATION FACILITY...... 9 2.4. GOAL AND OBJECTIVE...... 10 2.5. STATUS...... 11 3. PROJECT ORGANIZATION AND RESPONSIBILITIES...... 12

4. PROCESS DESCRIPTION...... 13

4.1. POLYMER FILTRATION TECHNOLOGY...... 13 4.2. EQUIPMENT DESCRIPTION...... 15 4.3. PROCESS OPERATION...... 16 5. METHOD, ASSUMPTIONS, AND PROCEDURES...... 17

5.1. APPROACH...... 17 5.2. RANGE OF OPERATING CONDITIONS...... 18 5.3. MEASUREMENT PROCEDURES...... 18 5.3.1. ANYALYSIS OF PROCESS STREAMS...... 18 5.3.2. EVALUATION OF PROCESS STREAMS...... 20 5.3.3. WORKER EXPOSURE TESTING...... 21 6. TASKS ACCOMPLISHED (RESULTS)...... 22

6.1. EQUIPMENT INSTALLATION...... 22 6.2. WASTEWATER PROCESSING...... 23 6.2.1. ZINC METAL RECOVERY...... 24 6.3. PROCESS STREAM EVALUATION...... 24 6.3.1. REUSE OF PERMEATE WATER...... 25 6.3.2. REUSE OF METAL SALT SOLUTION...... 26 6.4. WORKER EXPOSURE TESTING...... 27 6.5. RELATIVE PROCESS ECONOMICS...... 29 7. CONCLUSIONS...... 30

APPENDIX 1 – Hull Cell Test Results

iii LIST OF FIGURES

Figure 2-1: Polymer Filtration System and Output Streams...... 9 Figure 2-2: Schematic of Polymer Filtration Process on D-41 Zinc Line...... 11 Figure 3-1: Project Organization...... 13 Figure 4-1: Polymer Filtration Separation Schematic...... 16 Figure 4-2: Polymer Filtration Layout (Rear View)...... 16 Figure 4-3: Polymer Filtration Commercial Unit (Front View)...... 16 Figure 5-1: Composite Feed and Permeate Flows...... 19 Figure 5-2: Polymer Filtration in a Closed-Loop Plating Process...... 21

LIST OF TABLES

Table 6-1: Clean Water Permeate Rate...... 23 Table 6-2: Summary of PF Operation Results for AZD Demonstration...... 24 Table 6-3 : Zinc Recovery...... 25 Table 6-4: Hull Cell Coupon Composition...... 26 Table 6-5 : T-O1 Volatiles Results and Summary...... 28 Table 6-6 : Zinc Monitoring Results...... 27 Table 7-7 : Summary of Polymer Filtration Demonstration Results...... 31

1.0 EXECUTIVE SUMMARY

1.1 History

In February, 1997, the United States Environmental Protection Agency’s (USEPA) – National Risk Management Research Laboratory (NRMRL)

iv solicited demonstration project proposals from manufacturers and vendors of Approaching-Zero-Discharge (AZD) technologies. Upon an in-depth review process, by the EPA Common Sense Initiative (CSI) Metal Finishing Sector Research & Technology Workgroup Peer Review Panel, the PolyIonix Polymer Filtration system was selected as the first technology to be demonstrated. The company is commercializing this innovative technology know as Polymer Filtration (PF), which was originally developed under a Department of Energy (DOE) contract for the remediation of nuclear waste sites containing mixed wastes. PF is characterized by its ability to isolate targeted metal ions in dilute solutions from the other solution components, thus concentrating the targeted metal ions and producing an effluent essentially free of the target ions. The AZD Program has the goal of demonstrating, in an industrial setting, commercially available technologies, such as Polymer Filtration, to enable metal finishers to improve the economics and ecology of their production facilities through the recovery of valuable resources and the reduction in emission of toxic substances.

This Final Report summarizes the Task of demonstrating the PF system in an industrial setting.

1.2 Goal/Approach

The goal of this Task was to evaluate the technical and economic performance of the PF system as a method for the Metal Finishing Industry to prevent, remove, and control the environment risk to human health and the ecology from toxic metals. As well as, enhance the recovery of valuable resources.

The PF system was demonstrated at Pottstown Plating Works (PPW) in Pottstown, Pennsylvania. PPW is a major electroplating job shop, with the capability of plating zinc, chromium, tin, nickel, and copper on a 24-hour per day schedule. As most of their product throughput is in bulk and small in size, barrel plating technology is used. In terms of metal plated in this facility, zinc is predominant. The company uses approximately 4,000 lbs. of zinc per week. If the PF technology is successful, it will offer PPW an opportunity to regain the metal content of its plating bath (in this case, zinc) and reuse of its rinse water.

1.3 Results

This report contains the technical details and data analysis from the PF system demonstration at PPW during the testing period June 19 - July 1, 1998. The highlights of these results are presented here and are based on pilot scale testing (scale-up data is not presented):

v  An average of 99.4% of zinc was removed from the rinse water.  A 90-95% reduction in water requirements by recycling the “clean” water back into the plating process is expected with full-scale production equipment.  Ability to reuse “clean” water and metal salt solution without having adverse effects on quality of plated parts.  PF doesn’t raise worker exposure levels under limited operated time.  The PF economic impact is calculated at 56% less than the PPW’s current treatment practice when comparing the primary cost components on a per 1000 gallons treated basis.  Equipment payback is estimated at five (5) years.

1.4 Conclusion

In summary, this field trial successfully demonstrated the capability of PF to economically treat the process water in this facility and to remove zinc metal to levels well below their effluent limits. The PF field trial also demonstrated that recycling permeate water to the rinse tank and reclaiming metal solution to the plating bath doesn’t impact the plating quality. Field trial results were obtained specifically for this facility and conducted for a limited trial period.

Overall, in this field trial, the pilot scale PF unit demonstrated effective zinc removal and reuse of process water (indirect analysis). However, it did not meet the AZD economic payback objective of two (2) years or less.

1.1. AZD Peer Review Panel Comments

Comment (#1) The field demonstration fails considerably short of proving complete reuse of the permeate as rinse water makeup. Partial (20%) recovery of rinse water was demonstrated, however the economic feasibility appears to depend on avoidance of sewer use charges and thus requires virtually complete recycling of rinse water.

Comment (#2) Issues associated with contaminant accumulation in the bath and rinse water could not be adequately addressed in the limited field trials. The chemical characterization of the feed, permeate, and reject streams was limited to zinc, thus no information was developed for partitioning of other contaminants of interest.

Comment (#3) Long-term concerns regarding membrane life and flux decline could not be adequately addressed in the limited field trials.

vi Comment (#4) The analysis (economic and technical) doesn’t acknowledge a requirement for blow-down of salts. It appears that some discharge of permeate is unavoidable. It may be possible to achieve blow-down with a portion of the permeate while simultaneously achieving reuse. For example, it may be possible to direct a portion of the permeate flow to another location in the facility, thereby reducing raw water requirements by a corresponding amount. This redirection of the permeate would effectively function as a blow-down from the zinc plating line.

Comment (#5) The project appears to be very well laid out, however Hull Cell testing should not be the only criterion upon which to base an evaluation of the efficacy of the technology in recycling materials back to the plating tank. A thorough evaluation would be more appropriate that included micro- structure, adhesive properties, ability to accept a chromate film and corrosion resistance of the plate obtained from the recycled solution.

vii 1.2. 2.0 INTRODUCTION

The PolyIonix Polymer Filtration system was selected as the first technology to be demonstrated in the Approaching-Zero-Discharge (AZD) Technology Demonstration Project. The company is commercializing this innovative technology know as Polymer Filtration (PF). PF is characterized by its ability to isolate targeted metal ions in dilute solutions from the other solution components, thus concentrating the targeted metal ions and producing an effluent essentially free of the target ions.

This Final Report summarizes the Task of demonstrating the PF system in an industrial setting.

2.1 Background

The PF system combines water-soluble, metal-binding polymers, with ultrafiltration as a means for the separation, concentration, and recovery of metal ions in aqueous solutions. These metal-binding polymers contain functional groups which allow binding of specific metal ions in the waste stream. The polymer molecules are precisely sized such that they are entirely rejected by the ultrafiltration membranes, while all other soluble components of the waste stream pass through the membrane.

This process creates two streams (Figure 2-1; Page 8). One is essentially free of the targeted metal ion (“clean” water; permeate) and the other contains a concentrated solution of the targeted metal ion bound to the water-soluble polymer (metal salt solution). The permeate stream is recycled into the rinse process. The metal solution stream is pH-adjusted, which releases the metal ion from the polymer. The continued cycling of the metal solution through the membrane cartridge results in recovered polymer being retained by the membrane, while the purified concentrated metal ion solution passes through and is collected. This metal ion solution is then recycled back into the plating process or treated for recovery of the metal. The recovered polymer is recycled back to the PF system. The PF technology is designed for point-source reductions and is

8 especially suited for removal of metal ions at very low concentrations.

2.2 Purpose

The AZD program objective is to advance the understanding, development, and application of near-zero-discharge technologies and methods to the Metal Finishing Industry. This objective is intended to promote the prevention, removal, and control of environmental risks to human health and the ecology from toxic metals, as well as enhance the recovery of valuable resources. The goal of the PF system demonstration at PPW was to generate the analytical data and performance observations necessary to support the AZD program objectives.

Process Acid Base Inputs Stream

Metal-Polymer Metal-Polymer Metal Release/ Polymer Processes Binding/Separation Concentration Separation Recovery

“Clean” Water Metal Salt Regenerated Stream Solution Polymer

Figure 2-1: Polymer Filtration System Output Streams

9 2.3 Demonstration Facility

Pottstown Plating Works (PPW) is a major electroplating job shop, with the capability of plating zinc, chromium, tin, nickel, and copper on a 24-hour per day schedule. As most of the product throughput is in bulk and small in size, the plating technology used is barrel. Barrel plating is the plating of small parts, in bulk, in a rotating container (barrel) that is dipped into the electroplating bath solution. Zinc is the predominant material that is metal plated at this facility, consequently zinc recovery was the focus of this demonstration. The company uses approximately 4,000 lb. of zinc per week. This represents approximately 3,000 barrels of product per line, per week. PPW has three zinc/chromium lines, including line D-41 (36” barrel) of which the PF unit drew zinc rinse water.

Ordinarily, Rinse Tank #1 (the drag-out tank) would be the feed stream for the PF system. However, this demonstration was conducted on a pilot scale basis (PF process equipment and conditions: approximately 0.8 gallons per minute (gpm) and a 30 gallon process tank volume). The 30 gallon process tank limits the amount of zinc metal that can be treated by the PF system. In order to process the rinse solution, there must be a sufficient quantity (mass) of polymer in the process tank to bind all of the metal, which is presented into the unit through the process water solution. The concentration of the polymer in the process tank can limit the ability to pump the process solution through the UF membrane, because of viscosity. The combination of both the polymer concentration limitations and process tank size restricts the total mass of metal which can be processed by the PF pilot unit and consequently, the total volume of solution which can be treated between metal release steps at a given concentration.

As a result, the rinse water was drawn from Rinse Tank #2 and the permeate was returned to Rinse Tank #4 as indicated in Figure 2-2 (Page 10). The tank sizes are roughly 4 ft. (height-H) x 3ft. (width-W) x 3ft. (diameter-D) (122 cm. H x 91 cm. W x 91 cm. D), with a capacity of 300 gallons (1,140 liters). The use of Rinse Tank #2, which had a metal solution concentration of ~60 ppm, allowed ~370 gal. (~1,400 L) of rinse water to be treated per day. The drag-out tank (Rinse

10 Tank #1) was treated for several days after the AZD demonstration was completed. Only ~ 280 L. of rinse water was able to be treated per day.

2.4 Goal and Objective

There are two product streams resulting from the PF system; the permeate or “clean” water and the reclaimed metal solution. Of key interest within the AZD program is demonstration of the capability to reuse the products of the PF system within the facility or, failing that goal, of recovery of the Process Flow

Zinc Rinse Tank Rinse Tank Rinse Tank Rinse Tank Plating #1 #2 #3 #4 Tank

PF System Waste Treatment Pilot Unit

Figure 2-2: Schematic of PF Process on D-41 Zinc Line

valuable components in an economical manner either in- house or at an external facility.

The AZD objectives of the PF system demonstration at PPW were:

 Demonstrate PF unit operation.  Demonstrate recovery/reuse of valuable metals.  Demonstrate recovery/reuse of process water.

11  Demonstrate relative economics of PF system vs. current treatment.  Demonstrate that there is no increase in worker exposure to toxic substances due to the operation of the PF system.

2.5 Status

The Task objectives, as stated in Section 2.4, were accomplished through analytical testing of the zinc feed and permeate streams, workplace exposure testing, Hull Cell testing, and economic analysis. The Task activities were divided into two categories: critical and non-critical measurements.

Critical measurements were as follows:

 Effluent concentrations  Worker exposure  Hull Cell testing  Integrity of plating bath using recycled process water  Demonstrate process water reuse in the plant  Demonstrate recovery and reuse of zinc

Non-critical measurements were as follows:

 Relative economics of PF process vs. PPW current treatment practice

In order to achieve these measurements, the demonstration at PPW was performed as detailed in the EPA-NRMRL endorsed Quality Assurance Project Plan (QAPP).

3.0 Project Organization and Responsibilities

The AZD Program is funded by EPA with contributions-in-kind by the vendor of the technology being demonstrated. T. David Ferguson of EPA’s National Risk Management Research Laboratory (NRMRL) is the Program Manager, and Gus Eskamani of CAMP, Inc. is responsible for the program deliverables.

12 The hosting site, Pottstown Plating Works (PPW), supplied the power source, working area, small amounts of water, and all required acid (hydrochloric) and base (caustic) for pH adjustment in the process. In addition PPW supplied the general support of its employees in transporting equipment and wastewater solutions throughout the production facility.

Figure 3-1 (Page 12) displays the AZD Polymer Filtration demonstration project organization.

As the Technology Vendor, PolyIonix provided the Polymer Filtration equipment, staffing to install and operate the equipment, and ample supplies of the proprietary polymer (PolyMetTM Z) used for this demonstration. Anton Bricker led the PolyIonix project team. He also coordinated the activities and responsibilities for demonstration at PPW, which also included hiring independent contractors to perform worker exposure (Waterford Compliance, Ltd.) and analytical testing Program Management Program Deliverables Contractor T. David Ferguson Gus Eskamani (Air Sampling) EPA NRMRL CAMP, Inc. Waterford Compliance, Ltd.

Project Team Team Leader Contractor PolyIonix Anton Bricker (Aqueous PolyIonix Sampling) Blue Marsh, Inc.

Figure 3-1: Project Organization

(Blue Marsh, Inc.). During the entire duration of this demonstration project, a minimum of one engineer from the PolyIonix Project Team was on site to oversee the operation of the PF system at PPW. Additional resources from the Project Team were available for consultation and support functions as required.

4.0 PROCESS DESCRIPTION

4.1 Polymer Filtration Technology

13 One of the first applications for which the PF technology has been developed is the treatment of wastewater generated by the rinsing steps within industrial metal plating operations, both electrolytic and electroless. The PF technology utilizes water-soluble polymers, which have the capability to selectively bind with target metal ions. These polymer molecules have characteristics that allow them to be retained by an ultrafiltration membrane (retentate), while essentially all of the other components in an aqueous solution will pass through (permeate). Therefore, when the appropriate polymer formulation is selected for the isolation of a particular target metal in aqueous solution, the metal- polymer complex will be retained while the majority of the solution components (including most of the water) will permeate. When the polymer formulation is properly selected and the process conditions are well controlled within a proscribed range, the permeate is essentially free of the target metal. A schematic of the separation process is presented in Figure 4-1 (Page 14). The binding of the metal to the polymer and the separation/concentration process is conducted under controlled pH conditions, and can be operated in either batch or continuous feed mode. In “batch” mode, a single transfer of wastewater is made at the beginning of the process and the circulation of the solution through the membrane is continued until a minimum volume is attained in the process tank. In “mini-batch” mode, this process is repeated, with additional quantities of wastewater added to the concentrated metal-polymer complex solution remaining from the previous “mini-batch”, until all of the required wastewater has been treated. In “continuous” mode, the wastewater is continuously added at approximately the same flow rate as that of the permeate being discharged from the system, so that the volume of the solution in the process tank remains essentially constant throughout the entire run. When all of the wastewater has been transferred to the PF system, the process proceeds in “run-down” mode to reach the final minimum volume.

14 Figure 4-1: Polymer Filtration Separation Schematic

After processing of the waste stream is complete, the process conditions are modified to release the target metal from the polymer. The ultrafiltration process is then continued with the permeate output, now containing a concentrated solution of the target metal salt, being diverted. Simultaneously, the polymer is recovered within the PF unit for use in treating subsequent waste streams.

Since the PF process takes place entirely in solution, there are no appreciable diffusional limitations and the process kinetics are extremely fast. The selection of the polymer for binding specific target metals provides a selective approach wherein salts, such as calcium and magnesium, don’t interfere with the binding and don’t consume valuable capacity of the binding sites on the polymer. Due to both the strength of metal-polymer binding in forming the complex and the absence of any significant diffusional limitations, extremely dilute solutions can be effectively treated. The target metal can be concentrated hundreds or even thousands of times, resulting in large recoveries of water from the PF process for reuse or recycling within the production facility.

15 4.2 Equipment Description

The Polymer Filtration equipment utilized in this demonstration project was a commercial prototype. It is self-contained and includes all necessary equipment, such as pumps, reservoirs, process tanks, and associated plumbing. A drawing depicting the main system components is included in Figure 4-2 (Page 15) and a photograph of the pilot unit is in Figure 4-3 (Page 15). This pilot unit has dimensions of 4.4 ft. H x 3.3 ft. W x 3.5 ft. D (135 cm. H x 102 cm. W x 107 cm. D), a 30 gallon process tank, and has a maximum processing rate of 1.0 gpm (3.9 liters per minute – Lpm).

The scale-up to full-scale production would include both a larger filtration module (to allow increase of flow rates from 0.8 gal./min. to 16 gal./min. (3 L/min. to 60 L/min.) and a larger process tank (to allow treatment of much higher mass quantities of metal between metal release phases). Since the relative concentrations of all constituents in the rinse water should be the same between the Rinse Tank #1 & #2, the Technical Director and PolyIonix agreed that the scale-up should not present any technology issues.

Power requirements for pilot unit equipment was 220 VAC, 20 A, single phase and negligible quantities of water was required for normal operation. The equipment operations are controlled by a programmable logic control (PLC) module that automatically sets pump and valve operations for each phase of the process, as well as provide pH control.

16 Ultrafiltration Process Membrane Tank

Process Pump

Figure 4-2: Equipment Layout (Rear view) Figure 4-3: Commercial Prototype (Front view)

4.3 Process Operation

The PF unit process tank was charged with a sufficient quantity of an aqueous solution of proprietary polymer, PolyMetTM Z, to bind the target metal. The quantity of polymer added was determined from the total mass quantity of metal to be treated between metal release phases, within the concentration/viscosity limits, and the binding ratio, between the proprietary polymer and the target metal. The method used to determine the polymer concentration is proprietary and has been demonstrated to have a precision of 2.2% at the 95% confidence level. The quantity of polymer was controlled through volumetric additions of a solution containing a known concentration of the proprietary polymer. The rinse water to be treated was transferred to the process tank via a sump pump. At the same time the pH of the mixture was maintained at the optimal binding pH of 7.5 + 0.3 through feedback loop control of acid and base additions, using metering pumps that incorporate proportional-integral-differential (PID) control logic.

The process pump circulated the solution through the ultrafiltration membrane, where separation of the metal-polymer complex from the other components occurred. The permeate was discharged from the PF unit and directed to Rinse Tank #4, while the retentate was returned to the process tank.

The PF system was run in “continuous” mode for this demonstration, so the volume of the solution in the process tank remained essentially constant throughout the entire run.

17 When all of the wastewater had been transferred to the PF unit, the system proceeded in “run-down” mode to reach a minimum volume. .

18 When all of the wastewater had been treated and the volume of metal-polymer complex solution in the process tank had been reduced to a minimal quantity, the pH was automatically adjusted to 2.5 + 0.3. Hydrochloric acid was used to adjust the pH in order to release the zinc metal, as free zinc and chloride ions, from the metal-polymer complex. A process referred to as “diafiltration” was then conducted to separate the metal from the polymer solution.

Diafiltration is the process of adding water at the same time the permeate is discharged. The purpose of the diafiltration process is to essentially “wash” the freed metal ions out of the polymer solution. As a result, the metal ions pass freely through the ultrafiltration membrane as a zinc chloride (ZnCl) solution and the proprietary polymer is retained by the membrane. The source for the water used in this diafiltration process is a small portion of the water recovered from the concentration process. Thus, there is no fresh water requirement for this phase of the PF process. When the diafiltration process is complete, the polymer solution pH is raised back to 7.5 + 0.3. The regenerated polymer is now ready for reuse in the next PF system run and a concentrated, purified solution of the target metal is generated, which can either be recycled back to the plating bath or recovered.

The operating life of the membrane between cleanings is highly dependent upon the quality and composition of the waste stream being treated. In the case of this demonstration, there was no evidence of significant fouling from the rinse water treated. As a part of the PF process, the volume in the process tank is reduced to a minimum operating volume prior to the pH adjustment for metal release. As the volume is reduced, the concentration of the polymer increases with a concomitant increase in the viscosity, and thus a decrease in the flow-rate through the membrane. However, when the volume in the process tank is increased back to the normal processing volume, the flow rate through the membrane returns to its previous level.

5.0 METHODS, ASSUMPTIONS, AND PROCEDURES

5.1 Approach

The task objectives were met by performing activities according to the following:

 The demonstration, sampling, and testing were performed in accordance with the EPA-NRMRL endorsed Quality Assurance Project Plan (QAPP ).  Hull Cell testing was used to investigate the potential quality effects of recycling the metal salt solution (zinc chloride) into the plating bath. Hull Cell testing is a qualitative measure of plating process quality and was used to analyze the capability of reusing the metal salt solution. The manner for evaluating plating quality is strictly subjective and qualitative. The test coupons plated with plating solution are compared to those plated in the demonstration solution. The coupons are visually inspected for appearance

17 defects, such as cloudiness, lines, or spots, etc… If no deleterious effects are found, quality was deemed satisfactory.  Waterford Compliance, Ltd. (Limerick, PA), an independent contractor, performed air sampling workplace exposure testing to determine any changes in workplace exposure levels caused by the operation of the PF unit. Detectable metal and VOC exposures were compared to NIOSH exposure limits, ACGGIH Limit Values, or OSHA Permissible Exposure Limits.  Blue Marsh, Inc., (Douglassville, PA) an independent contractor, performed aqueous sample analytical testing to demonstrate the PF technology performance. The samples to be analyzed were the zinc feed stream (rinse water from Tank #2) and final permeate from the PF unit.  Test results were used to generally characterize the performance of the PF technology and to construct an economic model of operating costs.

5.2 Range of Operating Conditions

Primary control parameters for the Polymer Filtration process are pH, quantity of polymer, and quantity of metal in the process. Secondary control parameters include the flow rate of process solution through the ultrafiltration membrane unit, transmembrane pressure across the ultrafiltration membrane walls and, in the continuous process mode, the flow rate of the influent to the PF unit. These process conditions and operating parameters were monitored and logged, during the demonstration of the PF unit, by the PolyIonix team.

The following process data are obtained :

 Pressure drop across membrane  Process tank temperature  Retentate flow rate  Permeate flow rate  pH of process solution

5.3 Measurement Procedures

5.3.1 Analysis of Process Streams

An independent contractor, Blue Marsh, Inc., Douglassville, PA, was hired to perform aqueous sample analytical testing required to demonstrate technology performance. The samples to be analyzed were the zinc feed stream (the metal-laden rinse water from Rinse Tank #2) and final permeate (“clean” water essentially free of zinc) from the PF unit. Samples were collected and analyzed following EPA document 200.7, which outlines the specific collection and analytical procedures to be followed. Both streams were analyzed for zinc content. The analysis of the

18 permeate stream was to verify the effectiveness of zinc removal using the PF process. Composite samples were collected via the following procedure:

Collection of Composite Permeate/Feed Solution Feed and permeate lines were modified in order to collect composite permeate and feed solution for accurate zinc concentration analysis.

Each of the feed and permeate lines has a drain port. For the feed line, the drain port is located at the bottom of the feed line cartridge filter housing (Figure 5-1). For the permeate line, the drain port is located at the end of tee piping. Both drain ports have ¼” valves. These valves were connected to flow meters via plastic hoses. The meters have their own throttle ball valve to control the flow rate through the meters. The plastic hoses were used to connect the discharge ports of the meters to the carboys to collect permeate and feed composite solutions.

When the process began, both feed and permeate drain ports were adjusted so that the rates were proportional to the permeate rate. As the permeate rate increased or decreased, the composite feed and permeate rates were adjusted accordingly.

Feed Membrane Solution

Cartridge Filter Permeate Line

Composite Drain Feed Solution Valve Drain Composite Valve Permeate Solution

Flow Meter Flow Meter Carboy Carboy Sample Sample Port A Port B

Figure 5-1: Composite Feed and Permeate Flows

5.3.2 Evaluation of Process Streams

Of key interest within the Approaching Zero Discharge program is demonstration of the capability to reuse the products of the PF process

19 within the facility or of recovery of the valuable components in an economical manner either in-house or at an external facility.

5.3.2a) Reuse of Permeate Water from Concentration Phase

The “clean” water effluent was reused in Rinse Tank #4 on PPW’s zinc line. This rinse tank has an overflow rate of 5 gpm (20 Lpm), and the addition of the permeate from the concentration phase of the PF process provides the opportunity to decrease the influx of fresh water to the plating process by a corresponding amount. The use of the pilot scale PF unit for this demonstration limited this recycle rate to approximately one-fifth of the total flow requirement. However, full-scale PF commercial units are capable of processing at flow rates exceeding 30 gpm (110 Lpm).

The feasibility of replacing fresh water with permeate water from the PF process was measured by analysis of parts generated by the plating line, during this demonstration period. The generated parts were subjected to PPW’s manufacturing quality control procedures and inspections. Their quality control procedures and inspections did not indicate any adverse impact when using PF permeate water as substitute for fresh water in their plating operations.

5.3.2b) Reuse of Concentrated Metal Salt Solution

The reclaimed zinc salt solution from the metal release phase of the PF process has the capability to be recycled back to the plating bath.

In order to demonstrate this reuse capability, Hull Cell plating testing was chosen as the quality criterion and was performed. In these tests, the reclaimed metal salt solution from the metal release phase of the PF process was mixed with a genuine zinc plating bath solution in a ratio comparable to that, which would result if the entire reclaimed metal solution generated was added to the plating bath. This solution was then introduced into the Hull cell and its plating quality was compared with that generated by an identical test using only the plating bath solution, with no additional additives. Figure 5-2 indicates where Polymer Filtration can be placed in a plating facility to help “close the loop” and illustrates the ability to recycle and/or reuse the process streams within the plating facility.

20 PF Unit Recovered Plating Metal Solution Bath Regeneration P o l Flowing Rinse 1 y Rinse Water Ultrafiltration m Recovery e r Flowing Rinse 2 Polymer Binding Flowing Rinse 3

Figure 5-2: Polymer Filtration in a Closed-Loop Plating Process

5.3.3. Worker Exposure Testing

One of the concerns raised by the R&T Workgroup of the CSI Metal Finishing Sector was that the AZD technologies demonstrated must not increase exposure of the workforce to any toxic or dangerous substances.

An independent contractor, Waterford Compliance, Ltd. of Limerick, PA performed the air sampling and testing required to determine any changes in workplace exposure levels caused by the operation of the PF system. A series of exposure determinations were conducted for two consecutive days; one set during operation of the PF system, and one set under typical background conditions (PF system not in operation). Air samples were analyzed for volatile organic compounds according to the EPA Air Toxics Manual Test T-01, and for the zinc metal, the water treatment target ion, according to NIOSH Method 7300.

On the first day, both ambient and personnel sampling, during a complete operating cycle of the PF process in the working area of the on-site PolyIonix engineer, was performed. These traps were collected by the Waterford Compliance technician the same day. VOC samples were collected for a period of 1.5 - 2.25 hours and sampled in parallel (duplicate samples) on each test day. The method, under EPA Method T0-1, was collection on a carbon-based molecular trap, with subsequent analysis by GC/MS. Sampling was obtained via SKC Constant Flow air sampling pumps, and the flow rate was .02 -.04 gal/min (.06-.14 L/min). Calibration was performed with the relevant media in the sampling train prior to, and following, sampling. An FID was also used to obtain organic vapor readings during the sampling period. One field blank for VOC was obtained, and analyzed for each day of sampling. Zinc metal monitoring samples were collected over a period of four hours. Air samples were collected in the breathing zone(s) of the potentially affected workers. The

21 flow rate through the sampler was .66 gal/min (2.5 L/min). Samples were prepared, digested and analyzed via inductively coupled plasma (ICP) techniques. One (1) field blank was submitted and analyzed with the samples.

On the second day, the hygienist calibrated and placed a test trap in the area containing the PF unit, but without the Polymer Filtration system in operation, to develop a baseline measure of the zinc content of the air in the facility. The sampling period for this second set of background samples were again four hours for zinc and 1.5 - 2.25 hours for VOC. The results should be representative of a full 8-hour work shift as the process did not vary within the shift or within that sampling period. The results are therefore comparable to the OSHA PEL standards.

6.0 TASKS ACCOMPLISHED (RESULTS)

This section outlines the tasks completed to successfully accomplish the project objectives (as described in Section 2.4) and the specific results from those tasks.

6.1 Equipment Installation

PolyIonix installed the PF equipment. The electrical requirements necessitated the installation of a dedicated power line from a nearby circuit breaker panel. Flexible hoses were used to connect the PF unit to the wastewater transfer pump and to Rinse Tank #4 on Line D-41, which was used for discharge of the treated water.

The wastewater was transferred using an electrically powered sump pump from the rinse tank to a 250 gallon (950 liter) holding tank prior to PF unit introduction. Another sump pump was used to transfer the wastewater from the holding tank to the PF unit process tank. The holding tank was used in this demonstration to facilitate integration of the pilot unit into PPW’s operations, with minimal disruption.

Once the unit was in place and connected to power, approximately 20 gallons (75 liters) of fresh water was added to the unit and operation of all pumps, valves, and discharge ports were verified prior to beginning the process.

The total time expended for the installation and verification of the equipment operation was approximately two hours.

After installation of the equipment standard verification protocol for ultrafiltration membranes was conducted, which is one of the critical specifications for membrane unit performance. A membrane (ID # 93622016147) was installed for cleaning. Table 6-1 shows the clean water parameters for the membrane:

22 MEMB. MEMB. MEMB. TMP RETENT. PERM. TEMP O PIN POUT PPERM (PSIG) FLOW FLOW ( C) (PSIG) (PSIG) (PSIG) RATE RATE (GPM) (GPM) 28 18 3 20 18 2.5 31.3 31 22.5 3 24 15 2.8 31.4 35.5 30 3 30 9.5 2.8 31.5 Table 6-1: Clean Water Permeate Rate

The clean water rate indicates that the membrane was within membrane manufacturer operating specifications. The membrane performed well above the minimum specification for clean water flux (2.1 gpm) at Transmembrane Pressure (TMP) of 24.

The total time expended for the installation, verification of the equipment operation, and membrane cleaning was approximately four hours.

6.2 Wastewater Processing

During the testing period of 6/19/98 through 7/1/98 (weekdays only), the AZD zinc demonstration project was run per the QAPP. Table 6-2 shows the summary of results generated during the AZD demonstration. The column headings are as follows: date (the date of each PF run), [ZN] in rinse solution (the concentration of zinc in the rinse water feed to the PF unit, [ZN]R), volume of rinse solution treated (the volume of rinse water treated during each PF run), average process flow rate (average permeate flow rate during concentration phase of PF process), average [ZN] in permeate solution (average zinc concentration in permeate solution, [ZN]P), and average rejection coefficient % (fraction of zinc removed from the rinse water by the PF process). The average zinc concentration in the permeate water ranged from 0.19 to 0.43 ppm, which is well below PPW’s zinc discharge limit. The average rejection coefficient, defined as:

Rejection Coefficient (in %) = [1 - ([Zn ]P / [Zn]R ) ] x 100 ranged from 99.1 to 99.7 and is equivalent to the fraction of zinc removed from the rinse water by the PF process. The raw analytical QC data, was provided by Blue Marsh Laboratories.

[ZN] IN VOLUME OF AVERAGE AVERAGE AVERAGE RINSE RINSE PROCESS [ZN] IN REJECTION

23 SOLUTION SOLUTION FLOW RATE PERMEATE COEFFICIENT DATE (PPM) TREATED (GPM) SOLUTION (%) (GALLONS) (PPM) 6/19/98 88 374 0.80 0.23 99.7 6/22/98 52 372 0.70 0.34 99.3 6/23/98 48 374 0.70 0.23 99.5 6/24/98 55 374 0.70 0.19 99.7 6/25/98 61 374 0.70 0.31 99.5 6/26/98 53 374 0.70 0.29 99.5 6/29/98 61 275 0.60 0.43 99.3 6/30/98 61 276 0.70 0.21 99.7 7/01/98 68 276 0.60 0.39 99.4 Table 6-2: Summary of PF Operation Results for AZD Demonstration

6.2.1 Zinc Metal Recovery

The recovery of zinc metal from the rinse water treated in this demonstration was calculated by comparing the quantity of zinc treated during each day’s operation with the quantity of zinc collected during the metal recovery phase of the corresponding day’s process. The quantity of zinc treated was calculated by multiplying the volume treated by the concentration of the composite feed sample. The quantity recovered was calculated by multiplying the volume of metal recovery solution generated during the metal recovery phase of the process by the concentration of this recovered solution. The data are presented in Table 6-3. These results show that, within the limits of accuracy of the analysis and the measurement of the volume treated each day, the recovery of zinc from the PF process is excellent. The average zinc recovery for the PF demonstration, at PPW, was >100%.

ZINC CONTENT OF ZINC CONTENT IN METAL FRACTION DATE RINSE TREATED (lb.) RECOVERY SOLUTION (lb.) RECOVERED 6/19/98 0.28 0.30 1.1 6/22/98 0.17 0.20 1.2 6/23/98 0.15 0.17 1.1 6/24/98 0.21 0.21 1.0 6/25/98 0.21 0.23 1.1 6/26/98 0.19 0.20 1.1 6/29/98 0.14 0.16 1.2 6/30/98 0.15 0.17 1.1 7/01/98 0.16 0.20 1.2 Average Zn 1.1 Recovery

24 Table 6-3: Zinc Recovery Results 6.3 Process Stream Evaluation

As described previously, there are two process streams resulting form the PF process; the permeate, or “clean”, water and the reclaimed metal salt solution.

6.3.1 Reuse of Permeate Water

The permeate water generated by the concentration phase of the process is essentially free of the zinc metal ions targeted by the technology and has the potential for reuse either within the rinse tanks from which it was generated or in other applications within the facility’s operations. The permeate stream is by far the larger of the two streams generated in the PF process, and in this demonstration represented approximately 90 to 96% of the total volume of water processed.

The permeate stream was returned to the zinc plating line Rinse Tank #4. Examination, according to PPW’s manufacturing quality control procedures and inspections, of parts produced on the D-41 zinc line during this demonstration program did not indicate any deleterious effects due to the reuse of the permeate water.

It is estimated that the reuse of the permeate water in this pilot scale demonstration represents a savings of approximately 180 liters (48 gallons) per hour of fresh water input to the process, or 20% of the total usage for this rinse tank. It is believed that the 20% savings is a direct result of the pilot unit flow rate limitations. It is expected that the use of full scale production equipment, with flow rate capabilities matched to the cascade flow of the rinse system on line D-41, would allow 90-95% reduction in water requirements. 6.3.2 Reuse of the Metal Salt Solution

The plan for this demonstration project included evaluation of the feasibility of reusing the reclaimed metal salt solution from the metal release phase of the process. As described in the approved QAPP, comparative Hull Cell Testing was the chosen qualitative measure.

Hull Cell Testing is a qualitative measure of plating process quality. It was performed during this demonstration in order to investigate the potential quality effects that the recovered zinc chloride solution might have in the plating bath, without adding the solution directly to the bath. Hull Cell tests can be used to investigate the effects of additives on the bath chemistry over a wide range of current densities.

As shown in Table 6-4, increasing amounts of reclaimed metal salt solutions were used to provide an indication of problems that might be

25 expected when recycling the recovered zinc chloride solution. The reclaimed metal solutions from 6/29/98 through 7/1/98 were used to run the first Hull cell test. This testing was performed in PPW’s laboratories, by their technical staff. Each test scenario used 4 coupons of Hull cell and Table 6-4 shows the composition of each Hull cell.

COUPON 1 COUPON 2 COUPON 3 COUPON 4 Amount of Zinc Bath .07 .07 .07 .07 Solution used (gal.) Amount of Reclaimed 0 3.3 E-04 1.1 E-03 2.1 E-03 Metal Solution used (gal.) Simulated Amount of 0 15 50 110 Reclaimed Metal Solution Recycled (gallon) Table 6-4: Hull Cell Coupon Composition

The amount of reclaimed metal solution used simulates the amount of reclaimed metal solution recycled back to the zinc plating bath. Once all four coupons were plated, the 2nd, 3rd, and 4th were compared to the 1st coupon for the plating quality check. In the 6/30/98 testing, Coupons 3 and 4 were slightly discolored on the left corner possibly indicating too much organic in the plating bath, but, per the Technical Director of PPW, at these small concentrations, no effects outside of normal variation was noted. According to the Technical Director, this discoloration is a minor problem since organics can be easily removed by adding carbon treatment system before returning the reclaimed metal solution to the plating bath. Multiple Hull Cell tests were conducted. For the 6/29 and 7/1/98 samples, which immediately preceded and followed the 6/30 test, the testing results showed that there was no adverse effect in the plating quality when the reclaimed metal solution was returned to the plating bath.

To better gauge the effect of recycling larger amounts of recovered zinc chloride solution, PPW Lab technicians concentrated the constituents by boiling off water in the solution to these levels - Zinc metal, 0.425 oz/gal; Boric acid, 0.0 oz/gal; Potassium Chloride, 1.38 oz/gal. - which are equivalent to bath level concentrations. Necessary bath ingredients were then added back to this concentrated solution to make a new zinc plating bath, containing 100% of the reclaimed zinc metal as zinc chloride. Hull Cell testing was performed and the results were equivalent to the genuine plating bath used as the standard. See appendix 1 for a summary of the Hull Cell test results.

The entire Hull Cell test process was repeated and yielded the same, satisfactory results.

26 6.4 Worker Exposure Testing

Waterford Compliance Group, Ltd. was retained by PolyIonix to perform air monitoring during the PF demonstration. Monitoring was performed on two successive days as detailed in Section 5.3.3. The concerns addressed were employee exposure to zinc and TO1 airborne contaminants. All parameters were sampled following NIOSH, OSHA, and EPA protocols.

Table 6-5 (Page 28) summarizes the T-O1 contaminant sampling results and Table 6-6 summarizes the zinc monitoring results. The results for all parameters were well below their respective OSHA and NIOSH limits. Analytical results showed non-detectable or very low levels of the target compounds. Sample blanks returned acceptable results, and duplicate test results were within method criteria. As such, no adjustments were made for any blank values and all test run data are presented. Also, it should be noted that duplicate samples were not averaged.

Contaminant OSHA NIOSH 7-1-98 7-2-98 Limit Limit Zinc 5 mg/m 3 5 mg/m 3 0.0013 0.0015 Table 6-6 : Zinc Monitoring Results

It should be noted that the personnel monitoring in this demonstration program could be considered “worst case” in that the engineer operating the Polymer Filtration unit was continually in the immediate vicinity of the unit for most of the sampling time period. Under normal day to day operations, the person operating

27 Error! Not a valid link.TABLE 6-5 : T-O1 AIR MONTIORING RESULTS

28 the unit would only be working with the equipment for short periods of time during the day.

In summary, the study indicates that the PF technology demonstrated didn’t elevate employee exposures or exceed OSHA air quality limits. Thus, there is no evidence that operation of the Polymer Filtration process raises exposure levels of zinc in the facility.

6.5 Relative Process Economics

One of the objectives of this AZD demonstration was to perform a relative economic analysis between the PF process and PPW’s current treatment process, which is chemical precipitation. Chemical precipitation is achieved by adjusting the pH of the waste water with an alkaline reagent to reduce the solubility of the dissolved metals and then settling and removing the resultant metal hydroxide precipitates. There are five steps to this process: (1) pretreatment, (2) precipitation, (3) flocculation, (4) settling, and (5) sludge de-watering.

As mentioned previously (Section 2.3) Rinse Tank #1 would ordinarily be the feed stream to the PF system. However, this demonstration was conducted on a pilot scale which limited the amount of zinc that could be processed by the pilot unit. For the purposes of the economic analysis, full-scale implementation of the PF system was considered. It was assumed that treatment was conducted on the more concentrated (~925 ppm) Rinse Tank #1 stream and on all three zinc plating lines. The three zinc lines are located in parallel configuration and the waste streams can be easily and economically joined for treatment by a PF system. This flow would amount to approximately 15 gpm.

The permeate stream recycled to the rinse tanks is not expected to be 100%, due to the need to use water in the metal release phase of the PF process. The volume of water required for that phase represents 5-10% of the system throughput and depends on the original concentration of the rinse water being treated.

Any implementation of PF into a plating shop will have to be suited to the particular practices and procedures of that shop. The addition of a PF unit to the PPW shop would be in conjunction with other process design changes, specifically the incorporation of evaporation into the zinc lines to address plating bath “growth” issues. As a result, there would be no discharge of wastes by the PF unit. The by-products would be evaporated and disposed of similar to that of other by-products from existing evaporators. The capital cost of evaporators is not included in this evaluation as they encompass an independent project.

29 Many process and installation parameters were analyzed. Expense data were collected for the current waste treatment system and compared to savings associated with PF. A Cash Flow analysis was also completed with options of leasing or purchasing of a PF unit. Purchasing of the unit yields a 5 year payback.

Included in the economic analysis is potassium chloride recovery (KCl). This bath constituent is a major cost item and is constantly in the drag out into the rinses. With PF, this will be returned into the rinses from the permeate, avoiding loss of this component to the chemical precipitation waste treatment process.

Based upon the assumptions made and data gathered in this zinc demonstration, it can generally be said the economics of Polymer Filtration can compete well with chemical precipitation. Comparing the primary cost components of PPW’s waste treatment system --water, sewer, treatment chemicals and sludge disposal-- on a per 1000 gallons treated basis, the cost of treating zinc only with precipitation technology is $7.90. Using the same criteria, PF’s net cost per treated 1000 gallons is $3.50.

Net operational savings, as calculated using the data from this zinc demonstration, with PF would be $24,886 per annum. This economic analysis was generated by PolyIonix in concert with PPW’s Technical Director and Waste Treatment Manager.

7.0 CONCLUSIONS

In summary, this field trial successfully demonstrated the capability of the Polymer Filtration technology to economically treat the zinc rinse bath wastewater in this facility and to remove the zinc metal to levels well below effluent limits. The PF process also demonstrated that recycling permeate water to the rinse tank and reclaiming metal solution to the plating bath does not impact the plating quality. Table 7-7 (Page 31) summarizes how the PF unit measured up to the AZD objectives as described in Section 2.4.

With the exception of the two year payback, PF met the objectives of the AZD Demonstration Program. Based on the results of this specific demonstration, PF should significantly improve the economics and ecology of plating facilities through the recovery of valuable resources and the reduction of toxic substances.

30 PF UNIT AZD PROGRAM OBJECTIVES METHOD OF MEASUREMENT DEMONSTRATION RESULTS COMMENTS

Demonstrate recovery of zinc Analytical testing following OSHA, >100% zinc recovery Section 6.2.1 NIOSH, and EPA protocols.

Metal salt solution stream can be recycled Demonstrate reuse of zinc Hull Cell Testing into plating bath without causing adverse Section 6.3.2 quality effects on plated parts.

Demonstrate recovery of process Analytical testing following OSHA, Avg. zinc removal from process rinse water water NIOSH, and EPA protocols. was 99.4%; permeate stream had a zinc Section 6.2 concentration of 0.31 ppm.

Demonstrate reuse of process PPW manufacturing quality control Recycled permeate stream into rinse tank; no water procedures and inspections. indication of any deleterious effects to plated Section 6.3.1 parts.

Demonstrate relative economics Based on assumptions listed in Net annual operational savings with PF - of PF system vs. current Section and PPW’s input on current $24,886; 5 year payback if purchase PF unit; Section 6.5 treatment treatment practice. Comparing primary cost components, PF is 56% less than current treatment practice.

Demonstrate no increase in Air sampling following OSHA, The operation of the PF unit doesn’t raise Section 6.4 worker exposure due to PF unit NIOSH, and EPA protocols. worker exposure levels. operation

Table 7-7 : Summary of Polymer Filtration Demonstration Results at Pottstown Plating Works

31

Appendix 1 HULL CELL TEST RESULTS

SUBMITTED BY:

Fred Mueller, CEF PPW Technical Director 404 Rose Valley Road Southampton, PA 18966-3651 Pollution prevention practices by their nature create an opportunity for resource recovery or conservation. Barrel plating is an economical method to plate small parts in bulk. But, the extensive surface area of the parts together with their container (the barrel) will create a significant amount of drag out of the chemical solutions used in surface finishing. PolyIonix’s Polymer Filtration (PF) System offered Pottstown Plating Works, Inc. an opportunity to regain the metal content of the plating bath (in this case, zinc) that goes to the drain (waste treatment system) when you rinse the work in the barrel.

It’s very important to remember that it is the favorable economics of pollution prevention that drives the process. The recovered zinc chloride can be returned to the electroplating bath in two forms: as the recovered liquid zinc chloride, or after electrowinning, as solid zinc metal. Because of the extra process and energy needed for electrowinning we elected to examine the effects of returning the recovered zinc chloride directly to the plating bath.

Surface finishers are concerned that the direction pollution prevention is taking, pushing ever closer toward the finishing bath, will impact the quality of work coming out of the finishing bath. Traditionally, finishers have benefited from bath drag out because it can prevent contaminates from building up to levels that cause quality problems. This is especially true of barrel platers, like Pottstown Plating Works, Inc. We wanted to investigate the effect returning the zinc chloride might have on the quality of the plate without adding the solution directly to the plating bath. Hull cell can be used to investigate the effects of additives on the bath chemistry over a wide range of current densities.

Increasing amounts of reclaimed metal solutions were used to give an indication of problems that we might expect when recycling the recovered zinc chloride solution. At these small concentrations no effects out side of normal variation is noted. Too better gauge the effect of recycling larger amounts of recovered zinc chloride solution, we boiled off the water in the solution to concentrate the constituencies.

Concentrated sample: Zinc metal concentration 0.425 oz./gal. Potassium Chloride 1.38 oz./gal. Boric Acid 0.0 oz./gal.

We then added back to this solution the necessary ingredients to make a new zinc plating bath. Hull cell testing was performed and the results were as good as the plating bath we used as the standard. It should be noted that if organics become a problem, carbon treatment could be used before the solution is returned.

Pottstown Plating Works volunteered for this program because choosing the right high tech. equipment is close to impossible without some idea of how it works in a shop like yours. The wrong decision can be very costly. You need case study information in order to make intelligent choices.