Machine Coolants, Electroplating Operations, and Chemical Material Management at Norfolk Naval Base

Project Summary

By: Science Applications International Corporation
Cincinnati, Ohio 45203
EPA Contract No. 68-C8-0062, WA 3-70
SAIC Project No. 1-832-03-1021-010

Project Officer
Mr. Kenneth R. Stone
Pollution Prevention Research Branch
Risk Reduction Engineering Laboratory
Cincinnati, Ohio 45268

Risk Reduction Engineering Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268

Abstract

Three pollution prevention opportunity assessments were made of three selected processes at the Norfolk Naval Base, VA:

• machine coolant fluids;
  
• electroplating of nickel and chrome plating; and
  
• chemical material management system control.

Present conditions, proposed pollution prevention options, and conclusions and recommendations are provided for each process examined.

Machine coolants, used primarily for cooling and lubrication during machining and grinding, are degraded with use and by contamination. Frequent monitoring of the coolant by a qualified person was identified as a prime pollution prevention option.

At the Naval Aviation Depot (NADEP), Norfolk, hard chromium and nickel sulfamate electroplating operations are used to build up worn surfaces of metal parts, including engine and landing gear components. Some provisions for pollution prevention have already been implemented for NADEP. Among other sources of pollution, the PPOA found that a substitute degreasing process is essential. Substituting an aqueous cleaner with bath maintenance procedures was a suggested option.

Several areas for waste reduction regarding chemical material management operations were identified at the Norfolk Naval Supply Center (NCS). Although NSC has significantly reduced waste already, additional opportunities identified for further action are just-in-time inventory control, chemical storage and identification, waste exchanges, and employee education.

This Project Summary was developed by EPA's Risk Reduction Engineering 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 U.S. Environmental Protection Agency (EPA) has developed a systematic approach to identify, evaluate, and implement options to reduce or eliminate hazardous waste. The approach is presented in a report entitled, "Waste Minimization Opportunity Assessment Manual" (EPA/625/7-88/003). The procedure described in the EPA Manual provides detailed worksheets and a process/option evaluation method for use in industrial settings. To encourage use of this manual, EPA is conducting a series of assessment projects; the three reports summarized here describe the application of the pollution prevention assessment procedures to selected processes at Norfolk Naval Base, VA. This facility volunteered to participate in the project and provided technical support during the study.

The NADEP at Norfolk, VA, is one of six U.S. Navy facilities where aircraft are routinely overhauled. Each of these facilities employs up to 4,000 skilled industrial workers. The NADEP at Norfolk reworks F14 and A6 airframes, engines, and landing gear: complete disassembly, inspection of reusable parts, remanufacturing of parts, reassembly, and testing. The remanufacturing operations include numerous machining and metal finishing operations that generate significant quantities of hazardous and oily wastes.

Procedure

Pollution prevention is a policy specifically mandated by the U.S. Congress in the 1984 Hazardous and Solid Waste Amendments to the Resource Conservation and Recovery Act (RCRA). The PPOA used during this project is an acceptable approach for meeting one part of the PPOA program required by the law for hazardous waste generators.

The systematic PPOA assessment procedure can be used by a facility's own employees to identify pollution prevention opportunities. As a structured program, it provides intermediate milestones and a step-by-step procedure to

• understand the facility's processes and wastes,
  
• identify options for reducing waste, and
  
• determine if the options are technically and economically feasible to justify implementation.

This procedure consists of four major steps:

• Planning and Organization -- organization and goal setting;
  
• Assessment -- careful review of a facility's operations and wastestreams and identifying and screening potential options to minimize waste;
  
• Feasibility Analysis -- evaluation of the technical and economic feasibility of the options selected and the subsequent ranking of options; and
  
• Implementation -- procurement, installation, implementation, and evaluation.

The Waste Minimization Opportunity Assessment Manual contains a set of 19 worksheets designed to facilitate the PPOA procedure.

Machine Coolant Fluids

This study focused on the machining and grinding done in building LP-24. This facility contains approximately 100 machines used for manufacturing new aircraft parts and remanufacturing used parts.

Machine coolants are used primarily for cooling and lubrication during machining and grinding. Cooling is needed to remove heat from the tool and workpiece heat that is generated by the friction of the metal-on-metal contact. If left uncontrolled, the high temperatures would eventually damage the workpiece or the tool, or both. A good coolant:

• allows a faster production rate for a given tool's life,
  
• inhibits corrosion and bacterial growth,
  
• is free of objectional odors, and
  
• is nontoxic both for inhalation and for skin contact.

Coolant replacement is necessary when the coolant becomes contaminated which leads to degradation. Various interacting factors affect the rate of coolant degradation. The primary coolant contaminants are tramp oils flushed into the coolant system during machining and hydraulic oil contributed through leaking hydraulic seals. Other contaminants include metal particles, grease, and dirt.

The choice among the various types of machine coolants depends mostly on the cooling/lubricity requirements and cost. The available coolants can be categorized into four groups:

• synthetic,
  
• semi-synthetic,
  
• straight oil, and
  
• soluble fluids.

Synthetic and semi-synthetic fluids are generally more expensive than other types of coolants; however, they last longer. Straight oils are used infrequently because of health and safety problems such as fire hazards and slippery floors. Water soluble fluids, the most commonly used, contain an oil and an emulsifying compound and are diluted with water for use. The water provides cooling and the oil provides lubricity.

At the NADEP, two types of machine coolants are used:

• one for machining, and
  
• one for grinding.

Both are water soluble. Annually, 8 drums of coolant are purchased for machining (at $6.85/gal); four drums, for grinding (at $15.36/gal). Both coolants are diluted with tap water: a 5% concentration for machining and a 2% concentration for grinding.

Coolant must be replaced when it becomes contaminated; dirty coolant will degrade. Poor coolant cleaning techniques between changeouts hasten the growth rate of bacteria. Degraded and rancid coolant creates a very unpleasant working condition and a potential health hazard. Most sumps are changed every 1 to 3 months. When a coolant reservoir is changed, the spent coolant is pumped into 55-gal drums and shipped offsite for hazardous waste disposal by the Defense Reutilization and Marketing Office. Chromium in the spent coolant exceeds RCRA criteria for a toxic hazardous waste (D007). The transportation and disposal cost is $2.10/gal or $41,580/yr.

Hydraulic/lubricating straight oils are used in metalworking operations for noncontact purposes such as transferring energy hydraulically and lubricating gear boxes and moving parts in metalworking machines. During use, these oils become contaminated with dirt, other solids, and water, all of which can damage machine lubrication and hydraulic systems. These lubricating oils and greases are contained within enclosed reservoirs in the individual machines, except for way lubrication, which is used to lubricate the surface or slide (way) on which the carriage of a lathe, etc. moves along its bed. To reduce oil contamination and prolong equipment life, the oil must be filtered to remove dirt, solids and water.

The selected filtration equipment for the process baths is a portable unit with a 1-hp motor and a filtration rate of 12 gpm. It contains a 100-mesh reusable strainer and two duplex disposable filters, one set for particulate removal and one set for water adsorption. Various replacement filter elements with different micro ratings are available. The filtration unit has two 10-ft flexible hoses (inlet and outlet) for connecting to a machine or drum. A drip pan is located below the cartridge filters. Because of the newness of the hydraulic/lubricating oil maintenance efforts, no data are available to indicate their effectiveness.

Electroplating

Used parts typically arrive at the shop with an existing chromium deposit and varying amounts of grease, oil, and dirt. Initially, oils and greases are removed in a 1,1,1-trichloroethane (TCA) vapor degreaser. If the parts have an existing chromium deposit, this deposit is stripped; the parts are (sometimes) masked and placed into a caustic solution where a reverse current is applied to strip the existing chromium plate. After stripping, the parts are rinsed and placed into hot water to remove the bulk of the plastic masking. Small amounts of residual maskant are removed by returning the parts to the vapor degreaser. The parts are baked in an oven for stress relief to alleviate potential adhesion and cracking problems. To expose only the surface of the parts to be plated, the parts are then masked using a hot plastic coating, vinyl and aluminum tape, and aluminum and lead foils. After the parts are subjected to abrasive blasting with glass beads to ensure that the surface is clean and to roughen the surface to improve bonding of the chromium deposit, they are arranged on fixtures and electroplated in a chromic acid solution. The chromium plating process often takes 1 to 2 days to complete since thick chromium deposits (i.e., up to 0.05 in.) are usually applied and the deposition rates are slow (0.001 in./hr). The parts are rinsed, demasked in hot water and the vapor degreaser, and baked for hydrogen embrittlement relief. Abrasive blasting is used for the final cleanup, and the parts are sent to the machine shop for further processing (i.e., grinding).

Generally, hazardous wastes and wastewaters generated in plating shops can be grouped into six categories:

• spent process solvent and solutions resulting from contamination or exhaustion;
  
• rinse water;
  
• scrubber water blowdown;
  
• tank bottom sludges and solids from filter cleanout;
  
• miscellaneous chemical losses including spills and drips; and
  
• miscellaneous solids, including used masking materials and abrasive blasting dusts.

Nickel sulfamate plating is also used at NADEP, Norfolk, for many of the same reasons that hard chromium is used (i.e., to provide resistance to heat, wear, and corrosion). The mechanical properties of the nickel deposit are similar to hard chromium, although nickel deposits are slightly less hard. Nickel is applied in thick deposits, when required, for resizing worn surfaces. The speed of deposition is significantly faster than that for hard chromium plating and, therefore, the process takes less time to complete. Approximately 1,000 parts are nickel sulfamate plated annually at the NADEP.

The nickel stripping process is similar to that for chromium:

• vapor degreasing,
  
• acid cleaning and activation,
  
• stripping,
  
• desmut, and
  
• abrasive blasting.

Two types of stripping solutions are used, depending on whether the part is brazed or not. The nickel sulfamate plating process consists of degreasing, stress relief, masking (wax maskant rather than plastic), abrasive blasting, electrocleaning, acid etch, acid activation, nickel strike, and nickel electroplating. Each of the aqueous process steps is followed by rinsing. Wastes generated by the plating and stripping processes can be grouped into the same five categories discussed for hard chromium plating.

Chemical Material Management System Control (CMMS)

The NSC is one of many commands located at the Naval Base in Norfolk. Its mission is to "provide material/supply related services... to...all naval shore activities east of the Mississippi river and all units in the Atlantic and Mediterranean fleets." In addition to such services as procurement, customer services, and industrial support, the NSC performs equipment maintenance duties and maintains its own paint shop.

Hazardous waste generation from the NSC totaled 404,670 lb in 1991, including approximately 165,200 lb of paint, 19,400 lb of trichloroethylene (TCE), and 129,500 lb of cleaning compounds discarded as a result of having exceeded their shelf life. The NSC is considered a prime candidate for implementation of a chemical materials management system.

Results And Discussions

Machine Coolant Fluids

Potential pollution prevention options identified during the assessment phase are listed in Table 1.

Table 1. Potential Pollution Prevention Options for Machine Coolant Fluids

The prime options are frequent testing and control of coolants done by a single, qualified individual. The initial task would be an inventory of all machine sumps and reservoirs. The inventory should identify the machine, type and age of machine, sump and reservoir capacity, hydraulic/lubrication systems, and a measure of relative use. Subsequently, the coolant management person would develop and initiate a testing and control plan, and implement remaining inexpensive source reduction options.

Electroplating of Nickel and Chrome

Water meters are an excellent means of tracking water use at any plating shop:

• to aid in improving the water meter system improve instrument maintenance;
  
• place high level alarms on process tanks;
  
• segregate abrasive blasting workload; and
  
• maintain energy conservation.

The potential pollution prevention options for chromium and nickel plating are listed in Table 2.

Table 2. Potential Pollution Prevention Options for Nickel and Chromium Electroplating

The implementation of a substitute degreasing process is essential. To reduce present F002 waste quantities, the NADEP should consider:

• eliminating use of the existing old degreaser, which does not have provisions for solvent recovery; and
  
• minimizing use of vapor degreasing for heavy soil and grease and maskant removal.

The number 2 option can be implemented by using hand scrubbing and rinsing to remove as much maskant as possible before using the degreaser, or by improving the design of the vapor degreaser, or by both. The degreasers are conventional units with a boiling chamber, vapor or working zone, cooling zone, and freeboard. TCA use is 16 tons/yr (the shop's air permit allows a much higher emission rate). Discussions with NADEP personnel indicate that the majority of the TCA is lost through evaporation. Some TCA is removed as spent material and is drummed for disposal. The evaporative losses from the degreasers could be decreased by retrofitting the units with a refrigeration zone (freeboard chiller) just above the cooling zone. The refrigeration zone will condense vapors that escape the cooling zone.

The cost of the number one option is considerable and involves, perhaps, a 3-yr period to implement. During this time the use of vapor degreasing should be minimized.

The identified pollution prevention options for nickel stripping and electroplating mostly affect the quantity of process bath discarded and the amount of nickel lost through dragout. Preplating process baths, such as cleaners and acid dips, have a limited life span. Filtering (in-tank cartridge type) can be used to remove suspended solids and aid in maximizing bath life. Reusable filter cartridges are available that eliminate the bulky waste caused by throw-away cartridge filters.

Nickel can possibly be recovered from nickel strip solutions and rinsewaters for stripping, nickel strike, and nickel plate. The NADEP plans to install an electrolytic metal recovery (EMR) unit on the rinse following nickel sulfamate plating. The same EMR unit may possibly recover nickel directly from the spent stripping solutions. Recovered nickel can be used as anode material in the sulfamate nickel plating tank. If direct recovery of nickel from the strip solutions is not possible, the nickel can be removed using ion exchange. The EMR unit can then recover the nickel from the ion exchange column reagent. Similarly, ion exchange and the EMR can be used to recover nickel from the rinses following stripping and nickel strike. Also, as with chromium plating, high-level alarms and other devices for sensing spills and leaks could be used to prevent catastrophic chemical losses.

Chemical Material Management System Control (CMMS)

The Naval Base has already implemented a number of chemical materials management practices including:

• Delivering chemicals directly to requestors,
  
• Approving safety of all new chemicals before purchase,
  
• Having NADEP materials engineers investigate nonhazardous substitutes for process chemicals
  
• Recycling process solvents,
  
• Exchanging paint in an NSC-run Paint Mart, and
  
• By having the Naval Energy and Environmental Support Activity conduct solvent elimination studies.

In addition to the above initiatives, NSC Norfolk and the General Services Administration (GSA) have coordinated activities to overcome problems encountered by the NSC in obtaining supplies from GSA and to promote more efficient chemical materials management initiatives. Topics are discussed as follows:

• Shelf Life -- The GSA has proposed several methods of supplying shelf-life materials to the NSC Norfolk with the intent of providing maximum shelf-life, e.g., having vendor directly deliver priority chemicals, establishing direct requisition-specific codes, differentiating between materials that will be directly delivered and those stored, and initiating pre-stock agreements between the Navy and GSA for direct delivery materials.
  
• Paint Testing -- Through a Memorandum of Understanding between the Navy and GSA, the GSA will accept paint test reports from certain shipyards without the need for further laboratory verification of complaints.
  
• Packaging -- NSC Norfolk's storage facilities are designed to store pallets that have 5-gal can materials in a two-high configuration. Currently GSA ships pallets in a three-high configuration and shrink wrapped. This requires additional labor to re-configure the pallets for storage. GSA is currently working to alleviate this situation.
  
• Just-In-Time Delivery -- GSA and NSC Norfolk are reviewing this option. This will require detailed coordination between GSA and NSC Norfolk.
  
• Inventory Control -- A major waste generating source at the NSC is expired shelf-life materials. Inventory control is the most effective and cost-efficient method to prevent materials from becoming wastes. These control practices range in sophistication from simple operating procedures to complex computerized systems. A different type of complex inventory control system is based on the premise that the amount of materials stored at the facility is just the amount needed for operations; this eliminates excess inventory. Strict purchasing practices are adhered to with "Just-In-Time" policies -- only the minimum amount of a chemical needed for a specific job is purchased at a time, and the material is transported to the shop only when it is needed for production. This requires extensive pre-production planning and coordination.

Additional practices include the return of expired chemicals to the supply centers and having them either re-certified for use or returned to the chemical supplier. Some suppliers will credit returned materials against future purchases.

Seven additional pollution prevention options were analyzed for the CMMS. These potential pollution prevention options are listed in Table 3. Most of these options are based on management initiatives.

Table 3. Qualitative Assessment of Waste Minimization Options for the Naval Supply Center

Conclusions And Recommendations

Machine Coolants

Several of the options identified for machine coolant fluid operations require that preliminary investigative work be performed. The key inexpensive source reduction option is frequent coolant testing and control, and this should be done by an assigned coolant management person. The initial task would be an inventory of all machine sumps and reservoirs. The inventory should identify the machine, type and age of machine, sump and reservoir capacity, hydraulic/lubrication systems, and a measure of relative use. Subsequently, the coolant management person would develop and initiate a testing and control plan, and implement remaining inexpensive source reduction options. Because most of the pollution prevention options suggested for the NADEP have been previously implemented at other locations a basic research, design, and development effort, is not needed. Some investigative efforts and testing are, however, needed before certain operations can be implemented.

Nickel and Chrome Plating

In the electroplating process, F002 wastes can be eliminated by substituting an aqueous cleaner in the degreasing operation. The selection of effective cleaning equipment and chemistry will require an investigation of available technology and some testing. Because of the range of variables, the substantial cost of an aqueous cleaning system, and the installation/startup requirements, a 3 yr time period is estimated for implementation. During this interim period, use of vapor degreasing should be restricted to the newer unit which has an integral recovery still. Operators should be instructed to avoid use of vapor degreasing for heavy soil/grease or maskant removal.

Implementation of pollution prevention options for the selected hard chromium electron plating will require:

• collection of additional production and waste generation data;
  
• design of an integrated hard chromium plating system that includes conforming anode plating, effective dragout and emissions recovery, bath maintenance, and spill/drip pollution prevention;
  
• phased installation that prevents production shutdowns, and
  
• startup and training.

Implementation of the selected nickel sulfamate plating options involves a staged plan. Initially, tefforts should focus on bath maintenance (in-tank filters) and spill/drip pollution prevention (high level alarms, drip pans). These options are relatively inexpensive and easy to procure and install. Implementation of the nickel recovery options (strip solutions and rinses) will require some initial investigation and testing to define and, subsequently, to design a suitable system. To operate the system requires skilled labor, and training will be necessary.

Chemical Material Management System

In addition to the CMMS pollution prevention initiatives already undertaken by NSC Norfolk, seven options were identified to increase pollution prevention at the facility. Of these, three (chemical storages and material identification, employee education, and container management) were assessed as easily and immediately implementable. These options were fully compatible with the existing operating procedures and would result in a cost savings to NSC Norfolk with no effect on base operations. The container management option would require preliminary planning and would depend on organization requirements and supplier cooperation.

A fourth option, Waste Exchanges, was determined to be easily implementable, though partially compatible with existing operating procedures. This option would require changes in procurement policies and shop operating procedures and may require military specification changes. The cost savings were not determined; however, it appears that a slight increase in cost requirements as compared with current costs would be evident. Further evaluation of this option is needed before implementation.

The full report was submitted in fulfillment of Contract 68-C8-0062, WA 3-70, by Science Applications International Corporation under the sponsorship of the U.S. Environmental Protection Agency.

This Project Summary was prepared by the staff of Science Applications International Corporation, Cincinnati, OH 45203. Kenneth R. Stone is the EPA Project Officer (see below). The three complete reports summarized by this document are:

• "Pollution Prevention Opportunity Assessment: Naval Aviation Depot, Norfolk, Virginia: Electroplating of Nickel and Chrome",
  
• "Pollution Prevention Opportunity Assessment: Naval Aviation Depot, Norfolk, Virginia: Machine Coolant Fluids", and
  
• "Pollution Prevention Opportunity Assessment: Naval Aviation Depot, Norfolk, Virginia: Chemical Material Management System."

(Order No. XXXX-XXX-XXXXX; Cost $XX.XX, 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:

Risk Reduction Engineering Laboratory
U.S. Environmental Protection Agency
Cincinnati, OH 45268