Commonwealth of Massachusetts Executive Office of Environmental Affairs

Transcription

1 Commonwealth of Massachusetts Executive Office of Environmental Affairs Department of Environmental Management Office of Safe Waste Management 100 Cambridge Street Boston Massachusetts Michael S. Brown Director SOURCE RKDUCTION REOMENDATIONS FOR PRECIOUS MET& PLATERS Prepared by Office of Safe Waste Management Massachusetts Department of Environmental Management INTRODUCTION April, 1988 There are two major reasons for companies to evaluate source reduction practices. First, the company can expect that regulations will mandate further reductions in discharge concentrations of metal and chemicals allowed under wastewater discharge permits. With conventional wastewater treatment, it will become increasingly difficult, and in some cases impossible, to meet discharge limits as they reach the parts per billion range, particularly as the Environmental Protection Agency (EPA) limits discharge volumes. The second reason for close attention to source reduction is the potential cost benefit. Electroplaters generate significant quantities and varieties of hazardous wastes during the manufacturing process. Management of these wastes to meet water discharge standards by traditional means creates high volume waste streams such as metal hydroxide sludges and chlorinated solvent sludges that are regulated under the Resource Conservation and Recovery Act (RCRA) Amendments of Based on an analysis by the Office of Safe Waste Management, sludge precipitation and hazardous waste disposal required because of metal losses from plating lines cost one company more than $36.00 per pound of nickel disposed of as metal hydroxide sludge, and, because of the cost of cyanide destruction, nearly $ per pound of copper in sludge. >-house metals recovery, solvent substitution, process change and other source reduction techniques may significantly reduce this cost. Additional savings may be realized through improved resource management. In order to compare source reduction recommendations with current hazardous substance and waste management practices to ensure the use of the most efficient source reduction practices at the lowest cost, the company should do the following: 1

2 - conduct a detailed inventory including sampling to determine flow rate and metal and chemical concentration for each plating line and for each resulting waste stream and sludge; - conduct a cost analysis for present plating processes and waste management practices; - evaluate the location of present plating lines and plating room layout to determine the most efficient plating room plan, including opportunities for sharing source reduction equipment among plating lines; and - evaluate effectiveness of those source reduction practices implemented in the past. Once current costs of management of hazardous substances and hazardous wastes are known, the potential savings resulting from implementation of the waste reduction recommendations can be estimated. Implementation of the recommendations may also result in a reduction of long-term liability and financial risk. The following recommendations for source reduction in the plating room focus on in-house metals recovery and rinse management. Before deciding which recovery options to implement, the plating room layout should be evaluated for plating efficiency and multiple use of recovery equipment. Nickel Three alternative techniques are offered for implementation of source reduction and cost effective waste management in nickel plating. The first is the atmospheric evaporation system described in a recent study conducted by ILCO Unican Corporation1. Another is a rinse-reclaim system. The third is a multiple dragout system that is a simple combination of several standing dragouts. Additional alternatives to make each of the systems more efficient include installation of drip racks on plating baths and dragout tanks, drip boards installed between tanks on a slope in the reverse direction to that of the work flow and a high velocity mist spray rinse on the plating tank. The integrity of each nickel plating bath should be maintained by the addition of a carbon filter to remove organic contaminants and brightener breakdown products. In all cases, heating the rinse immediately p-eding the nickel plating tanks to approximately 150 degrees Fahrenheit will allow work to enter the plating bath at the same temperature l"feasibility Study of an Atmospheric Evaporative Recovery Application to a Nickel Plating Operation"; Brian Wells, Plant Engineer, ILCO Unican Corporation, Rocky Mount, North Carolina, for the Department of Natural Resources and Community Development, North Carolina,

3 as the bath. This should help to maintain the evaporation rate of the standing bath and avoid excessive cooling when work enters the baths. 1) ILCO Unican Corporation uses a closed loop system in which the plating bath is concentrated in an atmospheric evaporator and returned to the plating bath. The following recommendations are based on the findings of this study and those of a Minnesota study2 on the effectiveness of drip racks and spray rinsing. Work emerging from the plating bath is rinsed over the bath by a high velocity mist spray rinse, hung on a drip rack for 10 to 15 seconds, then rinsed in a series of four dragouts heated to approximately the same temperature as the bath, hanging on drip racks after each rinse for another 10 to 15 seconds. For barrels, retention time should be extended to at least 15 to 20 second^.^ The Minnesota study found that use of drip racks for this period of time reduces expected carryover by approximately 50 percent. All dragouts should be heated to improve rinse efficiency and to maintain a high evaporation rate. Dragout solution from each successive rinse is used as makeup for the preceding tank, with makeup for the plating bath coming from the first dragout tank. The desired nickel concentration in the plating bath is maintained in spite of dilution from the spray rinse and the addition of lower concentration water from the dragout by sending plating bath solution to an atmospheric evaporator. Evaporation should be adjusted so that the rinse flow will prevent contamination of the next plating line.4 Nickel concentrate can be returned directly to the plating bath, while water vapor can either be discharged to the atmosphere or condensed and returned to the last rinse tank. Figure 1 shows this system, using data from the ILCO Unican study. Because of the very high potential rate of evaporation, an evaporator could be connected to more than one plating tank. Figure 2 offers a flow balance and flow rate comparable to those in the attached study. It is particularly important to heat rinsewater in the multiple line system to maintain a high evaporation rate. 2t1Reducing Dragout in Copper and Tin/Lead Plating"; Rich Bosshardt, MnTAP Intern Program, Minnesota Technical Assistance Program, University of Minnesota, Minneapolis, Minnesota, The res-nce time on drip racks will be product-specific, as some metals may be susceptible to staining if allowed to dry on the rack. 4Returning highly concentrated effluent from the evaporator to the bath balances the bath dilution resulting from spray rinsing over the plating tank and return of the lower concentration solution from the first dragout. The concentration of effluent from the evaporator is approximately nine times grater than the dragout from the plating tank (Figure 1). 3

4 A potential problem with a shared evaporator is. at nickel baths of different plating chemistries may feed into it. As these cannot be combined and returned to the same plating tank, it may be necessary to invest in an evaporator for each type of bath, or, alternatively, to batch treat. A batch treatment tank can be used to store bath solution from a bath of one chemical constitution for night time treatment while treating the most heavily used nickel bath(s) during the day. Because of the cost of investing in several evaporative units, it may be worthwhile to evaluate use of the same plating chemicals in all nickel baths to the extent possible. In both cases, use of deionized (DI) water is recommended to avoid the addition of unnecessary salts. DI water will add to the cost of the installation, however, so the metal and salt content of city water and effluent from the wastewater pretreatment system should be evaluated for possible use. 2) The rinse/reclaim system consists of one dragout with liquid level controls and filter pump, followed by a triple counterflow reclaimer tank with liquid level controls and a transfer pump. The reclaimer tank contains three rinse chambers. Inflow to the system is controlled sufficiently to replenish the loss of solution caused by evaporation and dragout from the plating bath. The rinse/reclaim system returns lower concentration solutions upstream, to the dragout and finally, to the plating bath itself through a filter. These transfers are controlled by solenoid-operated liquid level controls and a pump system. The study from which the numbers in Tables 1 through 5 are derived5 indicates that the nickel concentration in the last chamber of the reclaimer tank never exceeded 7 milligrams per liter (equivalent to parts per million, or ppm). Table 1 also shows that if the last rinse or the combined rinse system flows at a rate of 0.7 gallons per minute (gpm), the nickel concentration of the plating room effluent will be less than ppm, the new NPDES permit limit for nickel discharged to the Ten Mile River in southeastern Massachusetts. 3) The multiple dragout system is the simple combination of several standing dragout tanks connected to one another. The higher the number of racks plated, the higher the concentration of nickel in standing dragout tanks. Table 2 shows the change in nickel concentrations in each tank of the four standing dragouts as a result of the number of racks plated. According to Table 3, although each dragout reduces the concentratjon of the previous tank by at least 70 percent, the nickel concentration in the final tank is still significant. Table 4 demonstrates the reduction in metal concentration made possible by 5t1Technical Data Sheet, Pollution Control & Waste Recovery Systems: Rinse/Reclaim Systems", Mirro-Brite Corporation, Coating Specialties Division, Providence, Rhode Island. 4

5 installation of drip racks, and Table 5 shows the water flow necessary to achieve the ppm discharge standard. Table 1 shows that when 200 racks go through the system, the nickel concentration in the last tank is 7 ppm, and the flow rate of the freestanding tank must be at least 0.7 gpm in order to meet the discharge limit of ppm. When the number of racks plated rises to 800, the nickel concentration in the last dragout increases to around 40 ppm, and flow rate of the last tank must equal or exceed 3.8 gpm. In this case, it is probably wise to combine the flow from nickel plating lines with that of lines dedicated to other metals to achieve the 3.8 gpm, rather than increasing the flow of a single tank or group of tanks to such a high flow rate. Use of spray rinsing, drip racks and drip boards can further reduce the flow needed to achieve the ppm standard. Table 4 demonstrates the concentration reductions estimated to be attained by adding drip racks and Table 5 shows the rate of inflow needed to achieve the ppm discharge concentration limit under three conditions of plating volume. These figures result from estimating a 50 percent reduction in carryover from each tank in the standing dragout system with a drip rack installed, as shown in Table 4. From a technical standpoint, the atmospheric evaporator system, which can close the loop, may be the best alternative we have seen for nickel plating line management. Compared with the multiple standing dragout system, the rinse/reclaim system has the advantage of automatic pumping and control, ensuring that nickel concentrations in the last chamber of the reclaimer tank are consistently low and independent of the number of racks plated. \ 5

6 . Table 1. Required Water Flow to Achieve Nickel Effluent Limit of ppm Without Drip Racks Flow Rate Dilution Required Necessary Type of Number of Ni Concentration To Meet To Meet System Racks Plated in Last Tank(ppm) Effluent Limit Effluent Limit( gpm) Rinse/ Reclaim System un 1 im i t ed (7 > 125 times > 0.7 klt iple- Dragout 200 system (with 500 Four Dragouts) > 125 times > 0.7 > 270 times > 1.5 > 720 times > 3.8 Source : Nickel concentrations taken from graphs in the attached study by Mirro-Brite Corporation titled "Technical Data Sheet, Pollution Control of Waste Recovery Systems : Rinse/Reclaim Systems". Assumptions: Workflow is about one rack per minute A typical rack drags 20 ml of solution out of each tank 6

7 Table 2. Nickel Concentrations in Standing Dragout Tanks Without Drip Racks Concentration After Plating Different Numbers of Racks Dragout 200 Racks Plated 450 Racks Plated 800 Racks Plated Tank Number Concentration (ppm) Concentration (ppm) Concentration (ppm) First Dragout Second Dragout Third Dragout iao Fourth Dragout Source: Nickel concentrations are taken from a study by the Mirro-Brite Corporation referenced above. Table 3. Percentage Reduction from the Concentration in the First Dragout Number of Racks Plated Dragout 200 Racks 450 Racks aoo Racks Tank Number Percent Reduction Percent Reduction Percent Reduction Second Dragout 87 2 Third Dragout a 94 Fourth Dragout

8 Table 4. Concentration in Dragouts with Drip Racks Installed Number of Racks Plated Drip Racks Tanks Installed 200 Racks(ppm) 450 Racks(ppm) 800 Racks(ppm) Nickel Bath Yes Dragout N1 no #2 no 83 no 114 no Nickel Bath Dragout #l #2 #3 84 Nickel Bath Dragout #1 #2 N3 # Nickel Bath Yes Dragout #1 Yes #2 Yes N3 #4 Yes no

9 Table 5. Water Plow Required to Achieve Nickel Effluent Limit of With Drip Racks Installed Flow Rate Number of Number of Tanks with Nickel Concentration Dilution Required To Meet Necessary To Meet Racks Plated Drip Racks* in DraRout #4(ppm) Effluent Limit Effluent Limit(gpm) times times times times times times 29 times times times times times times 0.25 * 1 represents drip rack installed on bath only 2 represents drip racks installed on bath and first dragout 3 represents drip racks installed on bath and first two dragouts 4 represents drip racks installed on bath and first three dragouts 9

10 Job shop platers in the Attleboro area generally have two copper plating operations, a copper strike and a heavier copper plate. Many copper strike baths in this area are maintained at room temperature. Thus most of the dragout solution cannot be returned to the plating bath, as evaporative losses will be minimal. We have observed one company that runs its copper strike at the 155 degrees Fahrenheit usually reserved for heavy copper plating in order to increase evaporation for dragout return. While adjustments in amperage and temperature may be necessary to retain the characteristics of a copper strike, it appears that these adjustments are feasible and will allow most of the dragout to be returned to the plating bath. A rinse/reclaim system like the one described for the nickel plating line can achieve reductions in carryover of copper similar to those for nickel. Adding an electrolytic recovery unit to the first dragout can be a cost-effective method of creating a veritable closed-loop system for metals management in the copper plating line. An electrolytic cell can reduce copper concentrations in the first rinse by plating copper out of the bath onto the cathodes. This will result in significantly reduced levels of copper discharged to the wastewater treatment system. The closed loop system would consist of a copper plating bath, a dragout tank containing the electrolytic recovery unit and three or four counterflow rinse tanks. Effluent from the dragout tank would feed the recovery unit, then return to this tank. With drip racks and drip boards, concentrations in the last tank should be low enough to create essentially a closed loop system. The determination of flow rate of the system depends on maintaining high recovery efficiencies in the electrolytic unit. Newer recovery technology has two significant characteristics. First, the cathode is a sponge-like material with a high surface area, enabling users to obtain good current efficiency at low metal concentration. This kind of electrolytic unit can be especially effective at removing copper from a lower concentration rinse. Secondly, the cathode is made of copper rather than more usual stainless steel or carbon fibers. If contaminant levels can be controlled by appropriate filtration, the fully loaded cathodes can thus replace anodes directly in the copper strike bath rather than being sold as scrap requiring further refining. The value of a copper anode is approximately $2.35 per pound of copper, versus $0.65 per pound of scrap copper. Where the3 are strikes or baths of similar composition in more than one line and operated under similar conditions, a company may want to evaluate the feasibility of merging the two lines. This will create additional space that can be utilized for in-house metal management or recovery for the copper line. Rinse management techniques can include either the rinse/reclaim system or the multiple dragout system described above, with or without electrolytic recovery. 10

11 Gold When rinsewater in a gold plating line runs 8 hours a day, 250 days per year at one gpm and discharges just one ppm gold to the sewer, the total annual gold loss from that single rinse will be 1 pound with a value of more than $6,000 a year. Effluent from final rinse tanks are not usually tested for gold concentrations, on the assumption that the gold loss is minimal. But gold discharge concentrations may be considerably higher than the one ppm in the example above. There are three cost-effective methods of reducing gold losses. The first is to reduce the volume of carryover from gold baths and all existing dragouts by installing drip boards and drip racks on baths and dragout tanks, the racks angled at approximately 30 degrees to obtain the fastest runoff from workpieces and the racks themselves. Residence time on the drip racks should be 10 to 15 seconds for rack plating and 15 to 20 seconds for barrel plating. Studies suggest that these residence times should reduce carryover from each tank by about 50 percent. The second alternative is to reduce gold concentration in the carryover from the last dragout to a running rinse. This can be done by setting up multiple dragout tanks or a rinse/reclaim system similar to those recommended for nickel management. A first dragout can be returned to the bath as makeup for evaporative losses and carryover depletion. The second dragout can be used to replenish the first, and so on. Studies indicate that the metal concentrations in a first dragout are reduced by 78 to 87 percent in the second dragout, 94 to 97 percent in the third dragout and more than 99 percent in a fourth dragout (See Tables 2 and 3). The application of drip racks clearly further reduces these concentrations by reducing the volume of carryover from the plating bath and each dragout. If companies install a single dragout tank for several color gold baths, the common dragout cannot be returned to individual plating baths. If it is possible to dedicate one or more dragouts to each color of gold, then returns can be made to individual plating baths. It appears to be feasible to operate all of the multiple dragouts as makeup for preceding baths when bath temperatures range from 145 to 155 degrees Fahrenheit. The third alternative is to recover gold from the first dragout tank to the extent possible. If gold return is not feasible, electrolytic recovery should be evaluated. Small in-tank electrolytic recovery units have been observed in several shops. These are immersed in the first dragout and reduce gold cpentrations and therefore carryover. The electrolytic recovery unit can be used with a single dragout tank and a counterflow rinse system common to several color gold tanks. Rinsewater can be further polished by means of an ion exchange column charged with a resin specifically formulated for use in low-concentration gold rinses. 11

12 Silver In most silver plating lines, returns to the plating baths are almost impossible because of low evaporation rates in the room temperature baths. Thus alternative metal management techniques must be evaluated. Drip racks should be installed on each tank to reduce carryover. Residence time for rack plating should be 10 to 15 seconds, while barrels should be allowed to drip for 15 to 20 seconds. A standing dragout-rinse/reclaim system consisting of a single standing dragout and three rinse tanks can be set up to follow each silver plating line. Water from the first rinse is used to replace evaporative losses in the dragout, which in turn replace evaporative losses from the plating tank itself. Because silver baths and rinses are maintained at room temperature, evaporation alone will not allow full return of dragouts and rinses. An electrolytic recovery unit can be installed in the dragout tank to reduce silver concentrations in the rinse system that follows. A metal-specific ion exchange resin column can be installed following the dragout containing the electrolytic recovery unit to polish the rinsewater. The determination of flow rate in the system is based on the need to maintain a satisfactory current efficiency of the recovery unit while preventing excessive silver loss to the conventional wastewater treatment system. Here again, it may be possible to use the in-line recovery equipment for more than one line. Rhodium In most companies in the Attleboro area, a single dragout tank follows the rhodium plating tank, and dragout is returned to the heated bath. However, because the price of rhodium is roughly triple that of gold, even small losses can result in significant loss of value to the firm. Thus installing drip racks and boards, a counterflow rinse system and in-house metal recovery equipment pays for itself relatively quickly. Three counterflow rinse tanks following a dragout tank, combined with drip racks on the plating tank, the dragout tank and the first rinse tank should create a nearly closed loop system. An electrolytic recovery unit with a high surface area metal sponge cathode can be installed in the dragout tank to recover rhodium. A metal-specific ion exchange resin column can be used to polish the rinse effluent. The science of metal recovery is making rapid advancements, allowing one small Attleboro job shop that installed a swll resin column to recover 150 grams of rhodium in six months. Tin In area companies, tin plating is a small part of the operation. Installation of three countercurrent rinses, drip racks and drip boards should significantly reduce tin loss from carryover. 12

13 Implementation of metals management recommendations will result in significantly lower water use, treatment and discharge. One company in the Attleboro area reduced its water usage from 23,000 gallons per day (gpd) to approximately 8,000 gpd by installing dedicated dragout systems for all plating rinses. To further control wastewater discharge, conductivity meters were installed on high use water lines, and pressure switches on lower use lines. Savings in water and sewer charges were $15,000 for the first year, while the cost of meters, switches and dragout tanks was repaid in less than three months. Conductivity meters can significantly reduce water use when installed on all final rinse tanks where closed loop systems are not used. The meter measures the conductivity in the tank, keeping continuous track of metal concentrations in the rinse water. It shuts off water inflow whenever conductivity drops below a preset value, as the metal concentration is sufficiently low so that further dilution is not necessary. It allows inflow again when the conductivity rises above another value, preset to ensure that water quality is maintained. Conductivity meters therefore have three advantages: they save water, reducing consumption to the strictly necessary level; they favor work quality, since the metal concentration in the rinse is continuously monitored and adjusted as needed; and they generate reduced volumes of wastewater requiring treatment. Two services offering energy audits are available to platers in the Attleboro area. Reliable Electroplating was audited under the Executive Office of Energy Resources audit program as a case study for the Southeast Project. When recommendations are fully implemented, savings are expected to exceed $3,400, or 22 percent the company's energy costs. If a company's energy bill exceeds $50,000 a year, an Office of Energy Resources audit can be requested by calling Bill Napolitano, at the Southeastern Regional Planning and Economic Development District ( ). For companies that spend less than $50,000 a year on energy, MassSave performs energy audits for smaller firms. They claim average savings of 12 to 15 percent. MassSave can be reached by calling their toll-free number, Alternatives to TCE Degreasing6 d A high priority in solvent management is to investigate alternatives for trichloroethylene (TCE). There are several substitutes on the market used by local jewelry plating shops. Platers have expressed satisfaction ' %bile TCE is the solvent discussed in this section, substitution and management recommendations are valid for other chlorinated solvents in use in this industry. 13

14 with the quality of oil and polishing compound removal, and with the cost savings that result from lower raw material use, increased bath life and the lower heating and cooling costs resulting from the use of at least one substitute. DEM compared the cost of using TCE in one small Attleboro plating shop with the cost of using two less hazardous alternatives, and found that the cost of using either alternative was less than half of the cost of TCE. However, if a company decides to continue use of TCE for degreasing, the following management practices should be adopted to reduce solvent losses, improve worker safety, and ensure compliance with solvent use and waste management regulations. Solvent Safety Controls I The following safety features have been used in several plating shops in the area. These safety features may prevent accidents in the shop. 1) A vapor safety thermostat should be installed. Placed above the cooling coils, the thermostat shuts off the heating element if the vapors rise to the preset point. The thermostat should be set between 30 and 35 degrees Fahrenheit below the boiling point of the solvent. 2) A boiling sump thermostat should be installed to shut off the heating element if the temperature of solvent-oil mixture in the sump exceeds the pre-set limit. The recommended value for this limit is up to 10 degrees Fahrenheit above the boiling point of the solvent, the temperature which indicates excessive oil contamination in the solvent. As a safety measure, it is also desirable to hard-pipe all drums or tanks of solvent so that virgin material is fed directly into the boiling sump. This avoids evaporative losses, vapor displacement and operator exposure caused by splashing when solvent is poured from a bucket or piped only to the top of the unit. Cooling Water A TCE unit should have at least seven cooling coils (nine or ten is better) and a cooling jacket to ensure adequate vapor control. Most units in the Attleboro area use city water for cooling. Incoming water reaching the unit may have increased in temperature significantly if the in-plant run is a long one, reducing its ability to remove BTUs from the degreaser vapors. Thesst of increasing flow to maintain the in-coming temperature of the water should be evaluated against the cost of a chiller that refrigerates and recirculates cooling water or refrigerant. Insulating the pipes between the city service and the TCE unit can also be evaluated: however, at $2.00 a foot for the coated pipe insulation necessary in the damp and corrosive plating shop environment, the payback period may not warrant the expenditure. 14

15 Operating Procedures for Solvent Units TCE degreasers are now required to have a large freeboard to reduce carryout of solvent vapors. The freeboard-to-width ratio should be at least 0.75, and for full control of solvent emissions, a freeboard chiller should be installed. Open-top degreasers should have covers that close automatically when they are not in use. These and the operating procedures outlined below not only help to meet environmental and health regulations, but also can reduce operating costs by 30 to 50 percent. As the rack 7 enters the vapor zone to degrease the workpieces, it causes the vapors to collapse. The rack should be lowered slowly into the unit, to avoid generating vapor waves that push vapors out of the unit. Whenever the vapors have dropped 2" to 4", the rack should be stopped until the vapors stabilize and start to recover. Only then should the rack be lowered further, until the vapors have dropped another 2" to 4". Barrels should be turned at each stopping point to ensure complete heating and cleaning. This "stop-and-go" technique prevents solvent vapors from being pushed out of the unit by the plunger effect of the rack. Once the rack is covered by the vapors, it should not be lowered further. This allows maximum vapor recovery with shorter cleaning cycles. The rack should be removed in increments of 2" to 4" with pauses to allow the vapors to be entrapped in the freeboard area. Again, with each stop, the barrel should be turned for maximum vapor release. This "stopand-go" procedure of withdrawal decreases vapor dragout. Once the rack has cleared the vapor zone, it should remain in the freeboard area until all parts are dry and no solvent drips from the rack (at least two minutes for racks and five minutes for barrels). This operating technique can be encouraged by installing a hydraulic lift set so that it will only lower/raise the work at the desired speed. will also serve as a drip rack after work leaves the unit. Angling the racks at approximately 30 degrees increases drying efficiency because it speeds solvent runoff from the racks themselves. It TCE Use II For more efficient use of TCE, an acid acceptance test,'' available from several companies, should be used. This test indicates the level of stabilizers present in the TCE and, therefore, when it must be distilled. It is easy to use and takes about one half hour. The test eliminates guesswork in wemining a TCE-cleaning schedule. This way, overuse or underuse of TCE is avoided. Overuse may affect work quality and cause corrosion of the unit. Underuse results in a higher than necessary consumption of TCE. 7The term "rack" will be used in this section rather than "rack or barrel'' unless the instruction for barrel management is different from that for a rack. 15

16 Approximately half of the companies in the Attleboro area use solvent dryers, while the other half uses air dryers. Spotting remains a problem with the air dryers presently in use. However, DEM cannot recommend use of chlorinated solvents such as TCE or PERC because of the potential for health and environmental damage. Nor can DEM recommend substituting a CFC8 dryer. Although the chemical has cost and quality benefits, it contributes to atmospheric ozone depletion and has been implicated in occupational health problems. Furthermore, DuPont, the major manufacturer of CFCs, announced in March that it will discontinue the manufacture of these substances. Air dryers are thus the drying technique of choice. There are several ways to make air dryers more efficient. First, rinses preceding the drying step should be heated to the temperature of the dryer. Adding a surfactant to the rinse immediately preceding the air dryer will increase the rate of water runoff. Before putting pieces in the dryer, use of as air blower as a low velocity air gun in order to remove as much water as possible and to leave as fine droplets as possible may reduce spotting problems. Hanging racks in the dryer at a 30 degree angle will help to ensure that water droplets will coalesce and run to the corners of the rack rather than onto the workpieces. Several vendors are working on new fan systems to improve air circulation within the dryer. And finally, improved insulation may reduce heating costs for the air dryer by as much as 30 percent. DEM is actively seeking a low-toxicity, efficient drying medium, but has not yet found one. DuPont's announcement that it will cease CFC production should encourage research into drying substitutes. Hazardous Waste Management Regulations Many firms in the area appear to have some difficulty in understanding hazardous waste management regulations. An outline of current accumulation, labelling and storage regulations for hazardous wastes for small, very small and large quantity generators follows. An information manual on recent changes in regulations for small and very small quantity generators is available. Legally, a company may accumulate up to one 55-gallon drum or its equivalent at the point of generation. This is called "satellite accumulation.>thus up to one drum of TCE waste, one drum of metal waste and one drum of each other type of waste generated may be accumulated at each point of generation. 8As Freon is a brand name, we use the generic term "CFC" for chlorofluorocarbons. 16

17 There is no time limit on storage at the point of generation of containers used for satellite accumulation, although they must be labelled as to their contents. However, according to both State and Federal regulations, when the 55-gallon container or its equivalent is full, the waste must be removed to a secure hazardous waste storage area, labelled and dated. After the waste has been moved to the designated storage area, you must dispose of it within 90 days for a large-quantity generator (generate more than 1,000 kilograms (Kg), or 2,200 lbs or 5 drums of waste per month or store more than 10 drums on-site at any one time); or within 180 days for a small quantity generator. The amount of hazardous waste that defines whether a company is a small or large quantity generator is irrespective of category, i. e. the definition refers to the total amounts of hazardous wastes of all kinds generated per month or stored at any one time. Thus if the company has more than a total of ten drums on site anywhere other than in "satellite accumulation" areas, it becomes a large quantity generator. Large quantity generators have to meet several requirements that do not apply to small quantity generators. These include filing of an annual report, increased requirements for employee training in hazardous waste management, written contingency plans, the designation of an emergency response coordinator, and notification of emergency response capabilities to the local fire and police departments, the Mayor, the Board of Health and the community emergency response team. The Department of Environmental Quality Engineering (DEQE) considers it a serious offense if a generator is generating or storing waste over the large quantity generator level, not declaring itself as a large quantity generator, and not labelling, dating and shipping off-site within 90 days. Drums containing hazardous waste, such as solvent wastes and metal sludges, must either be stored inside in a locked area labelled as a hazardous waste storage area or, if stored outside, be put in an enclosed and labelled covered area on an impervious pad. Any outside storage area must have containment for 110 percent of the volume of the largest container stored, in case of spillage. It is in the best interest of generators who legitimately qualify as small quantity generators to ensure that no more than 1,000 Kgs of hazardous waste is generated per month and a total (irrespective of category) 2,000 Kg of hazardous waste in tanks or 6,000 Kg in tanks is on site at any one time. (If 2,000 Kg of waste are stored onsite in containers other than tanks, then no more than 4,000 kgs may be kept on-site in a tank.) In new regulations promulgated in February, 1988, DEQE expanded the regulated universe to include generators of any quantity of hazardous waste above zero. 'RJIS generators of any quantity of hazardous waste are now responsible for complying with regulations applicable to the appropriate category of generator. However, realizing that companies generating less than 100 Kg a month of hazardous waste may find compliance excessively costly and difficult, DEQE has defined a new category of generator, the Very Small Quantity Generator (VSQG). The rights and responsibilities of VSQG status are defined below. 17

18 A VSQG generates less than 100 kilograms of hazardous waste in a month, generates no acutely hazardous waste, and has registered with DEQE as a VSQG. Registration forms are available from DEQE; A VSQG may recycle or treat waste on-site, providing the process described in the registration statement is acceptable to DEQE; A VSQG may transport his or her9 own waste in his own vehicle to another generator who is in compliance with the regulations and who will count the waste of the VSQG as part of the receiver's generation; A VSQG may transport his own waste in his own vehicle to a licensed treatment, storage or disposal facility or permitted recycling facility, or use a licensed transporter and a manifest form. (Use of the manifest requires an EPA ID number); Requirements for use of the self-transport option include: - transport only of waste that is generated by the VSQG on the VSQG's own premises; - transport of no more than 200 Kgs (55 gallons) at any one time; - transport of waste in containers no larger than 55 gallons, compatible with the waste, tightly sealed, labelled as hazardous waste, with the name of the waste and type of hazard, and tightly secured to the vehicle; - no transport of incompatible wastes in the same shipment; - notification of DEQE or the State Police, and the National Response Center's 24-hour toll-free hotline ( ) of any spill, release or leak that may threaten human health or the environment; - keeping a copy of the DEQE VSQG registration in the vehicle when transporting waste; and - compliance with federal Department of Transportation ( ) and state Department of Public Safety ( ) regulations. If a VSQG is transporting his own wastes rather than using a licensed transporter, aepa ID number is not necessary, nor is a manifest. However, the VSQG must keep records of type and quantity, date, method of transport and treatment/disposal method of all self-transported waste, as well as a receipt of acceptance of the waste by the receiving facility or generator. 9The term "his" will be used to mean "his or her" throughout this report. 18

19 These records and all waste analyses must be kept on-site for at least three years. A VSQG may accumulate, or store on site, up to 600 Kgs (approximately 165 gallons, or three 55 gallon drums) of hazardous waste with no time limit. The new regulations include new responsibilities for SQGs, including compliance with accumulation (storage) area standards, standards for containers and tanks, accumulation (storage) time limits, and emergency preparedness and response, although the latter are still less stringent than those for LQGs. These regulations are found in 310 CMR et seq. You are responsible for understanding and complying with them. Right to Know Regulations Many firms in the industry appear to have difficulty in achieving full compliance with Right to Know laws and regulations. Because of additional requirements under Title 111 of the Superfund Amendments Reauthorization Act (SARA) of 1986, it is important to examine Right to Know and OSHA compliance in detail. Under the Massachusetts Right to Know law and/or the OSHA Hazard Communication Standard, every container of hazardous materials and wastes, including raw materials, all plating, dragout and rinse tanks, must be labeled. Material Safety Data Sheets (MSDS) for all substances on the Massachusetts Substance List (MSL) must be kept on site, filed with DEQE, and used as the basis for the required annual training of all employees who might be exposed to any of these substances. We recommend that all companies participating in the SE Platers Project review their status under the Massachusetts Right to Know regulations and the OSHA Hazard Communication Standard as preliminary to achieving SARA compliance in a least-cost way. 19