By Brian Thomas and John Mukhar, P.E.

The City of San José (City) faces the challenge to preserve one of the most important estuaries in the United States alongside a socially and economically complex urban community. Over 1.2 million residents and 16,000 commercial and industrial businesses, including many of the leading high-technology firms in the country, are located within the San José/Santa Clara Water Pollution Control Plant (SJ/SC WPCP) service area. The City operates the SJ/SC WPCP according to the terms of its National Pollutant Discharge Elimination System (NPDES) permit. According to these terms, the City is responsible for limiting the discharge of pollutants to the South San Francisco Bay (South Bay). Nickel is one of the metals of concern that dischargers to the sanitary sewer and the storm drain system strive to reduce. The current SJ/SC WPCP NPDES nickel limit is 8.3 microgram per liter (ug/l) and an interim limit of 13.0 ug/l. The industrial discharge limit for nickel ranges from 0.02 to 1.2 milligrams per liter (mg/l).

As the twenty-first century approaches and technology continues to change at an extremely rapid pace, the environmental regulatory system must adapt. This transition, coupled with the decrease in effectiveness of the traditional regulatory system and increasingly stringent environmental regulations, led local governments to start developing more innovative management approaches to ensure continued environmental protection and restoration. Recognizing these challenges, the City, in cooperation with concerned stakeholders, developed a comprehensive watershed strategy to satisfy state and federal water quality mandates.

In the "City of San José, Pollution Prevention Strategy for a Clean Bay, Including Proposed Local Limits for Copper, Nickel and Cyanide, October 1994 Report," the City committed to a creative "partnership" program with four of the largest industrial dischargers within the City’s service area.

In late 1994, the City of San José decided to use a voluntary partnership approach with four of the largest nickel dischargers. This partnership explored possible solutions to reduce industrial nickel loading reaching the SJ/SC WPCP. The City believed that:

• A non-confrontational collaboration between dischargers and regulators could lead to additional reductions in the nickel mass.
• The partnership approach would be more productive and less disruptive to business than an adversarial regulatory approach.

The partnership between the City and the companies is committed to exploring and implementing methods and procedures that continuously reduce the amount of particulate and dissolved nickel reaching the SJ/SC WPCP.

The program was limited to four companies initially due to City personnel resource limitations. Ultimately, International Business Machines Corp. (IBM), Komag Inc. (three different sites), Sigma Circuits Inc., and AMC Substrates Inc. (a wholly owned subsidiary of Akashic Memories Corp.) volunteered to participate. These organizations accounted for approximately 35 percent of the industrial nickel loading to the treatment plant at the time of program inception. Management commitment by industry acknowledged that a regulatory problem existed and confirmed their sincere intent to commit resources towards industrial reduction efforts beyond those mandated under present regulatory compliance requirements.

Based on previous successes using Continuous Improvement (CI) theory and practices, the City’s Environmental Services Department (ESD) decided to apply these methodologies to the Nickel Initiative Partnership Program. This approach focuses on continual improvements of all aspects of the City’s and the companies’ waste treatment processes: the quality of system management, the exchange of information and data, planning and testing of new processes, and the training of the operators and managers in the use of statistical tools.

During November 1994, a Steering Committee was formed consisting of managers representing the companies and the City. The Steering Committee is responsible for managing the issues associated with the formation, growth and administration of this public/private partnership. The first eight months of 1995 were spent drafting legal agreements between the City and the four participating companies. The agreements covered confidentiality issues, utilization of patent rights, and the sharing of information among the companies.

After legal agreements were signed, the Nickel Initiative Partnership Steering Committee formed four cross-functional teams representing both industry and City staff working together in a collaborative effort to reduce nickel loads. The City provided a chemist, a source control inspector and an environmental engineer to each company team. The companies provided environmental managers, wastewater treatment operators, line managers, and production engineers to the teams. In addition, the City authorized up to $15,000 per company for analytical work to characterize each company’s process streams.

The legal agreements, under which the first phase of the partnership successfully operated, expired 30 June 1996. The partnership companies, by mutual agreement with the City, have extended their legal agreements to participate in the Nickel Initiative through 30 June 1997.

The company team members began meeting in June 1995, assembling baseline data and preparing flow chart diagrams of their waste treatment and manufacturing processes. During the month of September, following the signing of the confidentiality agreements, the City employees joined the teams. The City team members toured the waste treatment facilities and reviewed baseline data. All teams followed the same problem-solving framework and tracked their monthly results in nickel lb./day.

The teams feel that the partnership has allowed the City team members to see the real world problems of reducing nickel concentrations within the confines of current waste treatment technologies. Conversely, the companies have become acutely aware of the SJ/SC WPCP nickel limit and the difficult issue of treating dissolved nickel within the SJ/SC WPCP treatment system.

The partnership approach allowed the companies to reduce pollutants over a reasonable time. This timeframe for change allowed the companies to make small incremental changes in a variety of areas, while taking advantage of the dynamic changes in how they manufacture products. It is important to note that most of the technological changes were in place early in 1994 and the partnership encouraged the team members to continue to explore ways to optimize their systems via small incremental changes.

The partnership approach using cross-functional teams also allowed the companies to look into areas they had wanted to study but previously lacked the time or resources. The teams were able to leverage the resources of both organizations to achieve an improved performance. Also, the teams were able to capitalize on many small incremental changes within their systems to produce significant reductions in nickel mass. Table 1 compares the amount of nickel discharged by the partnership companies between the baseline year 1993 and 1996. This table also compares the performance of these companies with the other largest dischargers in the SJ/SC WPCP tributary service area.

Sigma Circuits Inc. is a leading quick-turn manufacturer of specialized electronic interconnect products, including multi-layer rigid printed circuit boards (PCBs), backplane assemblies and subassemblies, and flexible circuits. Sigma Circuits is a publicly traded company (Nasdaq) with annual sales of 88 million dollars. It has four divisions and approximately 775 employees. The division involved in this partnership is the Santa Clara Rigid Circuit Board Division. It manufactures prototype and pre-production quantities on a quick-turn basis. This division was established in 1974 and currently employs 230 employees and has about 38,000 sf of manufacturing area.

The Sigma Circuits Nickel Partnership Team first met in September 1995. The Sigma company team members had been meeting since the middle of June 1995. During that time, the company team members collected baseline information about the company’s waste treatment system and the current sources of nickel within the manufacturing processes.

The initial activities of the team members were devoted to understanding the treatment process steps and mass balancing the nickel coming from the manufacturing process. Establishing the baseline performance of Sigma’s waste treatment system required several 24-hour nickel composite samples to be collected. This data was critical for the evaluation of nickel mass balance and understanding the waste treatment process and its efficiency. It is important to keep in mind that being a printed circuit board manufacturer the main metals of concern at Sigma Circuits are copper and lead.

The team’s investigation of the waste streams’ flow and nickel concentration resulted in identifying the sources of 99 percent of the nickel. It was determined that the major source of nickel in the production processes is the rinse after the nickel bath (the deep gold line) accounting for 82 percent. Production processes contributed 99 percent of the nickel.

Since rinse after nickel bath was identified as the major source of nickel, the team focused on this process to control the nickel reaching the heavy metals tank in the wastewater treatment process. The mass balance also indicated that six percent of the nickel reaching the treatment process is discharged to the sewer system, and 94 percent is hauled off-site in the sludge. Table 3 and Figure 2 show the nickel mass balance.

The objective of the study of the wastewater treatment operation was to understand and control the different process parameters and operation factors in order to optimize this process. The steps that the team followed included:

• Flow charting the system
• Tracking results over time
• Analyzing data averages and ranges
• Studying critical process steps
• Eliminating root causes of variation
• Reducing variation between steps
• Designing experiments

The team members prepared control charts for Oxidation Reduction Potential (ORP) and pH at various steps in the treatment process. In addition, the team analyzed the nickel concentrations at various steps in this process. Evaluation of these control charts led the team to take actions to reduce the variability in some of these important waste treatment variables. A new ORP control was installed in the heavy metal tank so that chemicals were added at a proportionally controlled flow rather than as on/off additions. The pH in the heavy metal tank was monitored more closely to reduce the observed variations. In addition, the pH was increased to 9.5 to test if more nickel would precipitate. Figure 3 and 4 show some of the flow charts that were developed.

The team members continued the effort to understand and optimize the wastewater treatment process. The team started focusing on understanding and controlling the different process parameters and operation factors. They followed the summarized systematic approach to complete this work.

1. Tested One Factor at the Time:

2. Different Combination of Factors:

One of the factors studied was the relationship between pH, nickel concentration in the influent and effluent wastewater, and nickel removal efficiency. A total of fourteen composite samples were collected from the heavy metals collection tank and the wastewater discharge point, and the pH was adjusted in the range of 8.6 to 9.5. According to the experiment, it does not appear that nickel removal is pH dependent (for that pH range). The experiment showed that the higher the nickel concentration in the heavy metal tank, the higher the removal efficiency. The removal efficiency range in this test was 81-97 percent and the average was 86 percent. This relationship is shown in Table 4 and Figure 5.

Based on some of the preliminary results, the team has identified the need for a computer modeling program to assist in understanding and optimizing the wastewater treatment facilities. It was clear that a combination of conditions had to be optimized to improve nickel removal efficiency. Without a modeling program, it is practically impossible to achieve optimum results due to the number of possible permutations. It was decided to use the JMP software by SAS Institute Inc.

The DOE approach is a systematic structural development strategy for product/process engineering in order to characterize, optimize and control the product with minimum cost. This goal is accomplished by experimenting with many factors at the same time. This approach is typically used in the manufacturing processes. The team decided to apply the DOE approach to the existing pretreatment system at Sigma Circuits on a full-scale level (rather than a bench-scale) in order to reflect real life conditions and interactions.

The DOE factors are features that influence product/process quality. The team selected the following factors based on the criteria of potential significance to the process and the ability to control these factors in a full scale experiment:

• pH
• Oxidation Reduction Potential (ORP)
• Coagulant addition

The DOE responses are measurable quality characteristics. In this experiment, the team chose the following responses:

• Nickel (Ni) Removal Efficiency
• Copper (Cu) Removal Efficiency
• Lead (Pb) Removal Efficiency

Analyzing the results, the preliminary findings of the DOE experiment indicate the following trends:

• Coagulant concentration has a counter effect on Ni and Cu removal efficiency.
• Greater ORP value has a positive effect on Cu and Ni removal efficiency.
• The system can be designed to be insensitive to pH variation.
• There is a potential to optimize and stabilize the system for both copper and nickel removal.

The team will continue analyzing the data to fully understand the parameters' interactions, and to select the optimum points for pH, ORP, and coagulant additions.

Since November 1994, the City of San José, in collaboration with four major industrial corporations from Silicon Valley, has successfully implemented an environmental public/private partnership that has significantly reduced nickel loading to the sanitary sewer. Furthermore, the Nickel Partnership companies have accomplished an overall 50% reduction in their nickel industrial loading (pounds/day) since the baseline year of 1993. Remarkably, this decrease in loading occurred during a period of significant production increases (up to 350%) for each of the partnership companies. This decrease was essentially the result of basic research and development efforts to optimize industrial waste water treatment processes.

The two most important findings from this Nickel Initiative Partnership Program are:

• Learning how to set up an effective Public/Private partnerships and cross-functional work teams.
• The importance and effectiveness of using Statistical Process Control and Design of Experiment in industrial wastewater treatment systems.

The Nickel Initiative Partnership Steering Committee and work teams are continuing to explore innovative techniques to further reduce the nickel discharged into the sewer system and to develop new partnership pilots, sharing successes and findings with other companies in the SJ/SC WPCP tributary area.

Acknowledgments: The authors wish to acknowledge the Nickel Initiative Partnership Program Steering Committee; June Andersen, IBM Corp.; Randy Shipes, Komag Inc.; Brian Thomas, Sigma Circuits Inc.; Gary Winslow, AMC Substrates; Pete Higgins, Higgins & Associates; and Dan Bruinsma, Mary Ellen Dick, Karen McDonough, John Mukhar, Kirsten Struve and David Tucker from the City of San José Environmental Services Department. Also we would like to acknowledge the Sigma Team members: Jan Cimenello, Sergio Ramerez, and Mike Selvog, from Sigma Circuits, as well as Chris Lusseir from Cherokee Chemical Company Inc. and Sami Areikat, Mharr Dirige, and Bob Wandro, City of San José Environmental Services Department.

Brian Thomas, director of environmental affairs at Sigma Circuits Inc., has been involved in PCB manufacturing for the past nine years. Prior experience includes six years as senior Arctic engineer for Gulf Oil Corp. and ten years in meteorology and oceanography. He holds a bachelor’s degree in Meteorology from Penn State University.

John Mukhar, P.E., associate sanitary engineer, is the manager of the Environmental Engineering Section at the City of San José Environmental Services Department. He has been with the City for six years working on waste minimization and pollution prevention programs, and the Clean Bay Strategy. Prior experience include design and construction of water and wastewater treatment plants, and facility engineering. John holds a Masters of Science degree in Environmental/Civil Engineering.

For more information on the Nickel Initiative Partnership Program, please contact any of the City staff listed at 408-945-3000.