WORK PLAN ULTRASONIC CLEANING USING A HEATED INORGANIC CLEANING FLUID ERIE COUNTY/EPA WRITE PROGRAM EVALUATION NO. 2 - CONAX BUFFALO CORPORATION Prepared For: Erie County Department of ~nvironment & planning 95 Franklin Street Buffalo, NY 14202 Prepared By: Recra Environmental, Inc. 10 Hazelwood Drive, Suite 106 Amherst, NY 14228-2298 RE1 Project No. OC2448
1.0 INTRODUCTION 1.1 Background Conax Buffalo Corporation (conax) is a medium-sized business located at 2300 Walden Avenue, Buffalo, New York in Erie County. Conax is engaged in the design and manufacture of highlyengineered stainless steel components. Since 19 8 0, halogenated organics and chlorofluorocarbons (CFCs), including trichloroethylene, l,l,l-trichloroethane, trichlorotrifluoroethane (freon) and a freon/acetone mixture have been used at Conax. The CFCs are used for both degreasing parts after machining, and cleaning parts prior to assembly, shipment or stock. Until recently, four operations within Conax utilized CFCs: - Machining centers parts cleaning - Machine shop degreasing - Assembly vapor degreasing - Assembly final cleaning Although the use of CFCs resulted in zxtremely clean parts necessary for passing inspection, there were several disadvantages to their use: o Since freon has such a low boiling point (118O~), fugitive emissions are produced. 0 Fugitive emissions require reporting on IIForm Rff to comply with the Environmental Protection Agency's (EPA's) reporting requirements under SARA Title 111. o The cost of freon was increasing. o CFCs were targeted for eventual elimination due to their ozone depleting characteristics. o The use of CFCs was going to be taxed. o Reclamation of freon was possible, however hazardous wastes were still generated (i.e., F002 stillbottoms). After examining their operations and reviewing the disadvantages to CFC use, Conax decided to investigate alternative cleaning/degreasing processes and cleaning agents. In 1989, Conax initiated the first step in their program to eliminate the use of all CFCs plantwide. Within their machining centers, freon was being used in one and one-half gallon cans for degreasing metal parts. Conax successfully replaced these units with ten-gallon, hot aqueous cleaning systems. These systems,
which utilize an alkali (soap) based cleaning agent, have substantially reduced freon usage, fugitive emissions, and hazardous waste generation within Conax. The next step in their CFC elimination program was the removal of CFCs within the machine shop degreasing operation. Conax undertook an intensive investigation into various equipment and processes on the market to replace their 110-gallon freon vapor degreasing unit. Based on their research, Conax decided to replace their existing cleaning unit with a hot aqueous cleaning system utilizing ultrasonics. Conax and Chautauqua Metal Finishing Supply (CMFS), manufacturer of the ultrasonic cleaning system, agreed to participate in the Erie County/EPA WRITE Program in June 1991. The ultrasonic cleaning technology purchased by Conax will be the subject of a technical and economical waste reduction evaluation. This system will be compared to Conax, s existing freon vapor degreasing unit employed to clean various stainless steel components. 1.2 objectives Preliminary tests by CMFS on various stainless steel components manufactured by Conax demonstrated the effectiveness of an aqueous ultrasonic cleaning system for cleaning/degreasing. It is the intent of this WRITE Program evaluation to comparatively analyze the economic advantages of employing Conax's ultrasonic cleaning system for reducing both the use and generation of hazardous materials associated with conventional CFC usage. The freon vapor degreasing unit previously employed at the metal shop degreasing operation will be used for a comparison. The objectives of the aqueous ultrasonic cleaning system waste reduction evaluation are as follows: 0 to determine the economics associated with cleaning oil and dirt from stainless steel components using Conaxf s ultrasonic cleaning system employing an inorganic cleaning fluid 0 to determine the use and generation of hazardous materials from Conaxfs ultrasonic cleaning system 0 to evaluate the treatment performance of Conax's aqueous ultrasonic cleaning system in phase separating the surface contamination removed from the stainless steel components
1.3 Statement of Work An evaluation of ultrasonic cleaning using a heated inorganic cleaning fluid will be conducted at Conax's Walden Avenue facility to determine the economic benefits and associated waste volume and hazard reduction in comparison to freon vapor degreasing of various stainless steel components. The evaluation will be conducted according to the enclosed work plan. Sampling and analysis of wastes generated from the ultrasonic cleaning unit will be performed in accordance with the Quality Assurance Project Plan (QAPjP) for this evaluation. The results of the evaluation will be assimilated to determine the following: o waste volumes as a function of production/parts processed o presence/absence of pollutants associated with wastes generated o waste volumes using ultrasonic cleaning compared to freon vapor degreasing o economic benefits associated with ultrasonic cleaning o water usage impact using ultrasonic cleaning o labor and operating requirements and expenses associated with ultrasonic cleaning vs freon vapor degreasing A report summarizing the waste reduction evaluation of the ultrasonic cleaning system will be prepared for submission to the EPA. This report will include completed tables as depicted in Appendix A, as well as conclusions regarding the impacts which ultrasonics has on both cleaning/degreasing economics and waste reduction. 2.0 TECHNOLOGY DESCRIPTION 2.1 Aqueous Ultrasonic Cleaning Technology Ultrasonic cleaning is one of a number of methods which can be used for removing microparticulates from hard surfaces. Ultrasonic cleaning consists of immersing a part in a liquid medium, agitating that medium with high frequency (18-20 khz) sound for a brief interval of time (usually a few minutes), rinsing with clean solvent or water, and drying. The underlying mechanism behind this process involves microscopic bubbles in the liquid medium imploding or collapsing under the pressure of agitation, producing shock waves. These shock waves impinge on the surface of the part and, through a scrubbing action, displace or loosen particulate matter from that surface. The process by which these bubbles collapse or implode is known as cavitation.
There are no physical means by which actual cavitation action can' be measured. Thus, operators seeking to assess the performance of an ultrasonic cleaning system must rely almost exclusively on the evaluation of actual cleanliness levels achieved. The cavitation intensity in a sonic field is largely determined by three factors: 1. the frequency and amplitude of the radiating wave 2. the colligative properties of the medium (vapor pressure, surface tension, density, viscosity), and 3. the rheological properties of the liquid (static condition, turbulent flow, laminar flow). In order for cavitation to be produced in a liquid medium, the amplitude of the radiating wave must have a certain minimum value, usually rated in terms of electrical input power to the transducer. Cavitation intensity and, hence, cleaning effectiveness is greatly affected by the characteristics of the cleaning fluid. Flow characteristics, or rheological properties, also play an important role in ultrasonic cleaning performance. The design of an ultrasonic cleaning process must take into consideration the size, configuration, and capacity of the ultrasonic tank to accommodate the parts to be cleaned in an efficient manner. Certain basic rules which serve as guidelines in making design-related determinations are as follows: o Tank Loading: The total surface area of the substrate measured in square inches should not be much greater than the tank volume, measured in cubic inches. o Work Baskets and Fixtures: Work baskets or fixtures should have as little mass as possible, be made of metal (preferably stainless steel or some other hard, soundreflecting material), and be of open construction so that there will be minimal interference with the free passage of both sound waves and cleaning fluids. o Work Orientation: Parts to be cleaned should be evenly spaced throughout the tank volume and oriented with their narrowest dimensions toward the transducer radiating surfaces. o Location of Transducers: sonic transducers should be placed on the largest sides or on the bottom of the tank to allow for maximum distribution of sonic energy throughout the cleaning solution.
0 Power Requirements: The ultrasonic power requirements, expressed in terms of electrical-input wattage to the transducers, lie in the range of 50-100 watts per gallon of cleaning fluid, or 2.8-3.6 watts per square inch of transducer radiating surface (for piezoelectric transducers, most commonly used in ultrasonic cleaning systems). o Cleaning Fluid: Cleaning fluids should be carefully selected on the basis of (1) chemical and physical nature of the contaminants to be removed, and (2) identity of the substrate material. The operation of the ultrasonic cleaning system is also critical for the proper removal of particulate matter and other contaminants from substrate surfaces. operating parameters include : 0 Use of clean solvents and detergent solutions: The importance of using clean solvents cannot be overemphasized, since exposure to dirty solutions could easily result in the deposition of soils that are more difficult to remove than the original contaminants. o Wetting of substrates and contaminants: Wetting should usually be accomplished not more than a few seconds following introduction of the sonic fluid. 0 Prevention of redeposition: Continuous filtration or overflow, or both are required to remove contaminants from the cleaning solution so as to prevent redeposition onto the substrate. A flow rate equal to 50% of the liquid volume per minute is the maximum which can be tolerated without loss of cavitation. 0 Disposal or entrapment of contaminants: Substrates must be thoroughly cleaned following each ultrasonic cycle to remove all contaminated cleaning solutions. This can be accomplished through either spraying or vapor misting techniques, or ultrasonic immersion rinsing in heated water in order to maximize cavitation activity. 2.2 Conaxfs Miraclean System The Miraclean System is an ultrasonic cleaning system designed by Chautauqua Metal Finishing Supply (CMFS). It is a modular design of cleaning and rinsing tanks, employing an aqueous cleaning agent within the ultrasonic tank to accelerate the cleaning action (i.e., cavitation). Miraclean Systems have a variety of available options, such as additional rinse tanks and dryer stations, to meet individual customer cleaning requirements.
After reviewing Conax's needs for a replacement of their solvent based cleaning system, CMFS suggested their aqueous cleaning system (Miraclean System) as an alternative method of cleaning. To determine the applicability of the system, preliminary trial tests were conducted. Sample tests were run on representative parts sent to CMFS from Conax. The parts were made of stainless steel, aluminum, copper and/or plastic. The parts, designed with internal borings and threads, had color-coded ink markings that had to remain after cleaning. These parts were covered with the typical contaminants that Conax removed, including standard screw machine oils, water-based coolants, and in-house shop dirt. Conax had several criteria for the cleaner to be selected. The cleaner must: o be multi-metal safe o not etch aluminum o be compatible with plastic/nylon o be biodegradable o clean the above contaminants and o be free-rinsing. CMFS used a prototype cleaning system to clean the parts inhouse. After reviewing the criteria for cleaner and the types of contaminants to be removed, a powder silicated cleaner was selected as the best cleaning agent for Conax. Subsequently, the clean parts were sent to Conax for inspection. The cleaned parts met the Quality Department's final inspection product quality standards set by Conax. A second trial run was done with Conax representatives present. A 72" stainless steel pipe was cleaned using the powder silicated cleaner in an ultrasonic cleaning tank. The oils, chips, and dirt particles were removed. conax was satisfied that the Miraclean System would meet their quality standards for the variety of parts they needed cleaned. Based on the results of the preliminary trial tests conducted for Conax, a Miraclean System was designed for their specific requirements. A description of the system, shown schematically in Figure 1, is provided below. Conax's Miraclean System is comprised of (6) six stations: STATION 1: A LOADING STATION where the parts are placed in a basket for cleaning.
STATION 2: CLEANING TANK - Six (6) ultrasonic transducers are mounted on the side of the tank. The ultrasonic energy provides a mechanical scrubbing action. This action in conjunction with the cleaning agent quickly and effectively cleans the parts. The cleaning tank is designed with an interior grease trap/overflow weir. A sparger system is used to gently move insoluble oils and surface debris over the grease trap/overflow weir. These oils are contained in this area and are removed via phase separation. A pump and filter system is installed in the cleaning tank to remove suspended solids, chips and files. This extends the life of the cleaning solution. STATIONS 3 & 4: COUNTERFLOW RINSE TANKS - The purpose of a rinse tank is to dilute the concentration of cleaner that remains on the part to a level that is acceptable to Conax. A counterflow rinse system was designed to minimize fresh water use (see diagrams). In a counterflow system, fresh water flows into the third tank. This tank is designed with an overflow weir that empties into the second tank. the second tank has an overflow weir that collects insoluble solution that remains on the part after leaving the cleaning tank. By counterf lowing a single stream of water through two rinse tanks, the same water can be used twice. This greatly reduces the amount of fresh water needed to maintain acceptable rinse dilution. STATION 5: FINAL HOT RINSE - At this time, Conax will use the final tank for rinsing. Heat has been added to this tank to elevate the temperature of the part to help ensure quicker drying. STATION 6: UNLOAD SYSTEM - After leaving the final hot rinse, parts are cooled and removed from the baskets.
FIGURE 1 CONAX'S MIRACLEAN SYSTEM SCHEMATIC 'RESH JATER WATER TO DRA IN HOT RINSE COUNTERELOW RTNSE ULTRASONIC CLEAN 180"~ AMB AMB 150-180 F
The dimensions of Conax's Miraclean System are depicted in Figure 2. Overall, the system measures approximately 10' x 6.5' x 3' high. The work area, the area within the system where substrates are ultrasonically cleaned, measures approximately 9' x 1' x 1.5 deep. The system was designed to accommodate Conax's long stainless steel tubes. A plan view of the Conax Miraclean System is shown in Figure 3. This diagram shows the location and relative size of the ultrasonic cleaning equipment, including the transducers, heaters, temperature and other system controls, and the pump and filter system. The heating elements are positioned close to the bottom of the ultrasonic cleaning tank and hot water rinse tank. The six (6) transducers are lined up side-by-side along the largest side of the tank. A cover will be utilized for conservation of energy on the two (2) heated tanks.
3.0 WASTE REDUCTION EVALUATION The evaluation of Conax's Miraclean System on waste reduction will involve several phases. These. include: - obtaining background data on Conaxf s freon vapor degreasing unit - demonstrating the Miraclean System installed at Conax and collecting pertinent operating, performance and waste generation data - assimilating pertinent data from each process and comparing the results Phase I - Obtain Background Data on Conaxfs Freon Vapor Degreasing Unit Historical data regarding the use of Conaxfs freon vapor degreasing unit shall be obtained. This data shall include, but is not limited to: o Process Information - operation type - unit size, dimensions - throughput - operating procedures and costs - waste generation o Raw Material Use - freon use (type, consumption rate) - inventory data (delivery mode, transfer mode, container management) - cost of raw materials (purchase price, taxes, etc.) o Waste Generation Data - waste types and characteristics - generation rates (also as a function of production) - waste management practices - costs associated with waste generation The above information will be gathered from existing records at the Conax facility. Where pertinent data is not readily available, Conax will assist us in developing alternative data based on reasonable assumptions. Phase I1 - Demonstrate Miraclean System Installed at Conax and Collect Data The Miraclean System installed at Conax shall be operated and monitored for a one (1) month period to obtain pertinent data necessary for the waste reduction evaluation.
Log sheets operating sheets wi Department and Method will be available near the operation for recording key parameters during the demonstration period. These log 11 be maintained by the Machine Shop Degreasing Supervisor and reviewed by Conax's Facilities Engineer Proj ect Manager. Cleaning cycles shall be performed according to the Standard Operating Procedures (SOPS) for the System included for reference in Appendix B. For each cleaning cycle, the following information shall be recorded: Station 1 - Loadins Station - start time - types of parts to be cleaned, including parts description - approximate number of parts to be cleaned Station 2 - Ultrasonic Cleaninq Tank - start time - ph of tank - temperature of cleaning solution - stop time Station 3 - Counterflow Rinse Tank - start time - temperature of water - ph of water - flow rate of water - stop time Station 4 - Counterflow Rinse Tank - start time - temperature of water - ph of water - stop time Station 5 - Final Hot Rinse Tank - start time - temperature of water - stop time Station 6 - Unloadinq Station (Coolinq) - stop time
On a daily basis, additional data shall be recorded: - hours of steady state operation - weight of filters (when changed) - make-up added to cleaning tank (if any) - cleaning solution waste generated (if any) - oil quantities removed from cleaning tank overflow weir (if any) A sample Cleaning Cycle Log Sheet for recording data is included in Appendix C. Daily information regarding the system demonstration will be recorded on a Daily Log Sheet, shown in Appendix D. Erie County and/or Recra Environmental personnel will periodically observe the on-site demonstration of the Conax Miraclean System. From these observations, additional data which will be factored into the waste reduction evaluation shall be obtained. This data includes, but is not limited to: - system requirements (utilities, labor) during steady state (non-cleaning cycles) - maintenance requirements (supplies, labor) - production/work flow impacts - product quality influence - storage requirements (raw materials, products) - training requirements/system simplicity - system performance/reliability Product Quality Standards for parts cleanliness set by Conax will be maintained throughout the waste reduction evaluation. These standards are qualitative, not quantitative, and thus cannot be measured analytically. This WRITE Program evaluation will therefore depend on Conax personnel for their qualitative measurement of product cleanliness. A verbal description of this measurement is included in Appendix E. All wastes generated from the Ultrasonic Cleaning System are anticipated to be non-hazardous materials, based on the MSDSs for the coolant and cutting oils used for machining, and on the MSDS for the silicate cleaner. However, in order to evaluate the performance of the cleaning system in phase separation of the contaminants removed from the stainless steel components, various samples are required. Therefore, a sampling and analysis program will be conducted on the nonhazardous waste concentrate, waste oil and wastewater from the Ultrasonic Cleaning System. This analysis will focus on two distinct parameters; oil and grease, and TOC (Total Organic Carbon) for determination of the potential presence/absence of priority vs non-priority pollutants in these waste materials. Samples of the wastes will be collected and analyzed according to the QAPjP prepared for this evaluation. As indicated on the Cleaning Cycle Log Sheet, the ph of the various liquids will be measured throughout the evaluation.
Phase I11 - Assimilation 05 Data for cleaning Process Comparison Data obtained within Phase I and phase I1 of the waste reduction evaluation of Conaxfs Miraclean System shall be assimilated as Phase 111. Data assimilation will include calculations for each cleaning process relative to: - total operating costs and labor requirements (hours and costs) - raw material consumption and cost - utilities use and cost - maintenance requirements (labor hours, supplies and costs) - production throughput (annual and costs basis) - waste generation quantities - waste transportation and disposal costs Conax will supply all necessary cost data relative to the purchase and installation of the Miraclean System (purchased equipment, utility connections, ancillary equipment, start-up, etc.). This information will be reported for the reader's knowledge. 4.0 EVALUATION SUMMARY AND CONCLUSIONS The results of the waste reduction evaluation of Conax's Miraclean System will be summarized for comparison with the use of the freon vapor degreasing process. Among others, the following results will be documented: o raw material costs per part cleaned o operating costs per part cleaned o waste generation per part cleaned o waste disposal costs per part cleaned Final results will be presented in tabular form, according to the tables included included in Appendix A. 5.0 PREPARATION OF REPORT A report shall be prepared after the evaluation of Conax's Miraclean System has been completed. This report shall include the findings and conclusions of the evaluation, according to the outline presented in Appendix F. The completed tables identified in Section 4.0 will be included in the final report. 6.0 PROJECT SCHEDULE The anticipated schedule for completing the tasks in the work plan is presented in Figure 4.
APPENDIX A ULTRASONIC CLEANING SYSTEM EVALUATION FINAL REPORT TABLES
SUMMARY OF DESIGN AND OPERATING CHARACTERISTICS FOR CLEANING TECHNOLOGIES CHARACTERISTIC System Capacity (units per hour) FREON VAPOR DEGREAS ER AQUEOUS ULTRASONIC CLEANING SYSTEM System Mobility (transportable, fixed) ~ogistical Operating Requirements: 2 Space (area) (ft. ) Water (gals. per hr.) Electrical Power (amps) (volts) Sewage Access (yes/no) Labor Requirements (man hours/cleaning cycle)
SUMMARY OF RAW MATERIALS USE FOR CLEANING TECHNOLOGIES FREON VAPOR DEGREASER AQUEOUS ULTRASONIC CLEANING SYSTEM Raw Material Used: Product Type Usage Rate (lb./year) Delivery Mode Transfer Mode Empty Container Management Raw Material Cost: Purchase Price ($/lb.) Taxes (if applicable, $/lb.) Total Cost ($/lb. ) Storage Reqyirements: Area (ft. ) Special Precautions
SUMMARY OF OPERATING PROCEDURES AND COSTS FOR CLEANING TECHNOLOGIES FREON VAPOR DEGREASER AQUEOUS ULTRASONIC CLEANING SYSTEM Avg. Length of Cleaning Cycle (min/cycle) Avg. No. of Cleaning Cycles per Year (#/yr) Avg. No. of Parts per Cleaning Cycle (parts/cycle) Utility Requirements: Energy (KWH/yr. ) Water (gal./yr. ) Labor Requirements: System Operation (man hours/yr.) Maintenance (man hours/yr. ) Raw Material Usage: Freon (lb./yr.) Silicate Cleaner (lb../yr.) Operating Costs: utility Costs ($/yr. ) La.bor Costs ($/yr. ) Raw Material Costs ($/yr.) Total Operating Costs ($/yr.)
SUMMARY OF WASTE GENERATION FOR CLEANING TECHNOLOGIES FREON VAPOR DEGREASER AQUEOUS ULTRASONIC CLEANING SYSTEM Waste Type/Quantity (lb./yr. ) : Hazardous: Freon Non-Hazardous: Concentrated Cleaner Rinse Water Cooling Water Oil Filters Air Emissions: vocs Total Waste Quantity (lb./yr.) Mgmt. Practice Cost Mgmt. practice cost Waste Management Practice/Cost ($/yr-): Freon Concentrated Cleaner Rinse Water Cooling Water Oil Filters vocs Total Waste Management Cost ($/Year)
SUMMARY OF CLEANING TECHNOLOGY EVALUATION Raw Material Cost per Part Cleaned ($/part) operating Cost per Part Cleaned ($/part) Waste en era ti on per Part Cleaned (lb./part) - total - hazardous - vocs Waste Disposal Cost per Part Cleaned ($/part) FREON VAPOR DEGREASER AQUEOUS ULTRASONIC CLEANING SYSTEM REDUCTION
APPENDIX B ULTRASONIC CLEANING SYSTEM EVALUATION STANDARD OPERATING PROCEDURES FOR CONAX'S MIRACLEAN SYSTEM
APPENDIX C ULTRASONIC CLEANING SYSTEM EVALUATION CLEANING DEMONSTRATION LOG SHEET
ULTRASONIC CLEANING SYSTEM EVALUATION CLEANING DEMONSTRATION LOG SHEET Date : Operator: STATION 1 - LOADING STATION Start time: ~escription No. of parts to be cleaned: 1-15 (diameter, 15-100 length, material 100-1000 type) : 1000+ Parts Configuration: tubes other STATION 2 - ULTRASONIC CLEANING TANK Start time: Stop time: Elapsed time: 0 ph: - Temperature ( F) : Flow Rate (gpm) : STATION 3 - COUNTERFLOW RINSE TANK NO. 2 Start time: Stop time: Elapsed time: 0 ph: - Temperature ( F) : STATION 4 - COUNTERFLOW RINSE TANK NO. 1 Start time: Stop time: Elapsed time: ph: - Temperature (OF) : STATION 5 - FINAL HOT RINSE TANK Start time: Stop time: Elapsed time: Temperature (OF) : STATION 6 - UNLOADING STATION (COOLING) Stop time: Inspection: - Clean - Not Clean - Return to Station 1
APPENDIX D ULTRASONIC CLEANING SYSTEM EVALUATION CLEANING DEMONSTRAITON DAILY LOG SHEET
ULTRASONIC CLEANING SYSTEM EVALUATION CLEANING DEMONSTRATION DAILY LOG SHEET Day Hours of Steady State Operat ion Make-up Added (gal) Water Cleaner W A S T E Oil from Cleaning Tank Weir G E N E R A T I O N (lb) Filter from Cleaning Cleaning Tank Waste Tank Recycle Solution 1 2 3 4 5 6 7 8 9 10 11 12 13
APPENDIX E PRODUCT QUALITY STANDARDS
PRODUCT QUALITY STANDARDS Final Inspection: Products which have been cleaned using either the Freon Vapor Degreasing Unit or Aqueous ultrasonic cleaning System are visually inspected in the Quality Department's Final Inspection area. Cleaned parts may contain no visual residues or white powder in order to pass inspection. They must be completely dry. Parts which do not pass final quality inspection must be returned to the finishing department and be re-cleaned.
APPENDIX G OUTLINE WASTE REDUCTION EVALUATION REPORT EXECUTIVE SUMMARY I. Introduction 11. Technology Description 111. Description of Technical and ~conomic valuation IV. sampling and Analysis Plan V. Data Summary and Analysis A. Historical Data on Facility B. Operating Data Summary C. Performance and Analytical Results D. Economic Evaluation VI. Evaluation Summary and Conclusions Appendix: Quality Assurance and Quality Control Procedures and Results