Dynamic Pollution Prevention Proaram

Transcription

1 Dynamic Pollution Prevention Proaram r. Provides Results Industrial case studies showcase pollution prevention success stories in Orange County, Cali$ he County Sanitation Districts of Orange County, Calif., recently initiated the final phase of a program to control and reduce the quantity of toxic materials discharged by industrial users to its sewer systems. The fist phase, in effect since 1982, has relied on enforcement requirements mandating the implementation of pollution prevention by industrial dischargers. The final phase expands the program to consider crossmedia and nonindustrial pollution prevention options and create a partnership with industry. The agency provides wastewater treatment for more than 2 million pee ple in 23 cities and unincorporated areas of Orange County. It treats more than 225 million gallons per day of residential, commercial and industrial wastewater at two regional treatment plants that discharge to the Pacific Ocean. More than 1,000 companies are regulated under the agency s federally approved pretreatment program. Of that number, 450 are considered signifi- cant industrial users as defined by EPA The agency s pretreatment program includes industrial permitting, inspection, monitoring and enforcement actions to ensure protection of public health and the environment. Activities for preventing toxics from entering the sewer system include aggressive source control, and the promotion of pollution prevention and continuing education programs directed at promoting safe industrial and household waste disposal practices. These activities are part of the agency s 30-year plan, 2020 Vision, which integrates research, facilities planning, environmental analysis, toxics control, water conservation and reclamation, sludge reuse and other innovative programs into a unified strateu. In May 1992, the agency received an EPA National Pollution Prevention Award in recognition of the program s outstanding contribution to environmental protection through pollution prevention. In the beginning. The history of the agency s sourcecontrol activities By Adriana Renescu and Margaret H. Nellor can be traced back to 1970, when the Industrial Waste Division - now the Source Control Division -was established to issue permits, set flow and quality limits, and monitor industrial discharges to the sewer system. During the program s inception in the 1970s and throughout the early 1980s, the agency regulated discharges of heavy metals, oil and grease, organic materials, dissolved solids, suspended solids, phenolic compounds, radioactive wastes, combustible materials and other contaminants with the potential to degrade the wastewater treatment processes or the marine environment. A formal pollution prevention program began in 1984, when the agency implemented a policy to control and reduce the quantity of toxic materials discharged by industrial users to the sewer system. This program was developed in response to a new philosophy favoring source control and waste minimization over end-of-pipe treatment. To encourage wastewater reduction and water conservation and prevent companies from relying on dilution to achieve compliance, the agency adopted mass emission rates for each permitted industrial discharger. Mass emission rates were calculated on the basis of an analysis of samples taken from a facility and its average water usage. These rates then were compared to permit limits. As part of this initial effort and subsequent enforcement of mass emission rate limits, facilities were required to install flow restrictors or control valves to regulate August/September

2 and limit the flow of wastewater to the sewer. In addition to routine monitoring and inspections, industrial facilities are checked at least annually for water conservation control equipment Another important element of the program during its early stages was the advocacy of waste minimization techniques as tools whereby companies could achieve compliance with discharge standards. Companies discovered that waste minimization practices, such as waste segregation, countercurrent rinses, drag-out tanks and flow restrictors, reduce waste volume and lower pretreatment costs and sewer-use charges. In September 1989, as part of the revisions to its sewer-use ordinance, the agency included provisions establishing pollution prevention requirements. In essence, these provisions required all industrial users to develop pollution prevention plans, investigate new technology, provide inventory control, implement educational and training activities, and take any other steps needed to minimize waste. Todays program. Today, enforcement actions are still the agency s primary method for encouraging pollution prevention. Pollution prevention requirements are incorporated into enforcement actions taken against noncompliant companies through written orders and compliance schedules; In response to an action, companies must conduct pollution prevention assessments and implement any economically feasible methods or techniques that will ensure long-term compliance. Descrip tions of proven waste minimization techniques, their application and benefits, and a waste minimization checklist are provided to assist companies in their evaluations. Companies also must prepare written operating procedures and provide operator training. As part of this approach, an engineer is sent to each facility to review its manufacturing processes and, through permitting and compliance activities, assess pollution prevention opportunities. In addition to these enforcement-related activities, the agency also participates in technical outreach efforts for the industrial community by sponsoring and attending workshops on waste reduction and pollution prevention. In the program s second phase, which was initiated at the end of 1992, an extensive effort is being made to market pollution prevention and champion the incorporation of pollution prevention ideals into each discharger s way of doing business. Through informational and educational FIGURE 1 Total Heavy Metals Concentrations in Raw Sewage a5 a7 a9 91 B Yeur FIGURE August/September 1993

3 outreach, the agency is promoting pollution prevention as the preferred alternative to all other control methods. The Pollution Prevention Task Force, which includes agency officials and industry representatives, was established to discuss pollution prevention and other topics of interest to industry. The first step of this second phase was an extensive survey to determine the extent of industry s pollution prevention efforts. Of the 247 companies that received the survey, 54 percent responded and indicated they had implemented some type of pollution prevention measure. Except for a small number, most respondents said they had implemented at least two pollution prevention techniques, mostly technical modifications. Small industrial sources and commercial dischargers also are being brought into the program. Results. Since the program began, 95 percent of metal finishers and other federally regulated industries have installed flow restrictors or control valves to reduce wastewater usage, or have implemented various measures to reduce the volume of hazardous waste and wastewater discharged to the sewer system. Significant environmental improvements have been achieved. In the past five years, total heavy metals in the agency s raw sewage has been reduced approximately 50 percent, and greater reductions have been achieved for specific constituents (Figure 1). For example, cadmium has been reduced by 90 percent, chromium by 86 percent, cop per by 62 percent, lead by 82 percent, nickel by 66 percent and zinc by 74 percent. The overall reduction in toxics has been so effective that, for the past three years, heavy metals concentrations in incoming raw sewage have met the agency s NPDES discharge standards (Figure 2). Case Studies These case studies illustrate distinctive waste management practices for different types of facilities; demonstrate the technical and economic feasibility of implementing pollution prevention techniques; and demonstrate the availability and utility of such options for similar industrial facilities. All three companies are classified as significant industrial users. Organic chemical industry. Company A, which employs 31 people, blends a variety of industrial and household cleaning products and places them in aerosol containers. Production involves a batch process; each formulation contains a specific blend of water, organic solvents and anhydrous compounds. Organic solvents used in the formulation are methylene chloride, 1,ldichloroethene and l,l,l-trichloroethane. Alcohols and glycol ethers also are used. Before the implementation of pollu- 177

4 FIGURE 3 I FILLING PROCESS I S Liquid Process, Unchanged D Liquid Process, Modified - Aerosol Cans, Unchanged tion prevention techniques, organic chemicals from two storage tanks were sent to one of five tanks, where products were mixed in batches. Mixed products then were pumped to the aerosol line used to fill containers. Full cans were taken to a gassing room, where they were injected with propellant. Pressurized cans then were taken to a hot water bath, where they were tested for leaks. Wastewater was generated primarily during formulation, batching and rinsing of the mix tanks; there was little wastewater discharge from the filling process. However, there was potential for the leak-testing procedure to generate waste, because leaking material remained in the bath, which overflowed to the waste discharge system. Wastewater discharges from the facility ranged from 800 gallons per day to 3,600 gallons per day, depending on the production level. Wastewater passed through a claritier before being discharged to the sewer. After significant violations of its discharge permit, the company was given a probation order requiring it to assess and resolve its noncompliance prob lem. In response, the company evaluated its processes and identified three waste management options: install an end-of-pipe treatment system; install and implement pollution prevention techniques, such as process changes, operational modifications, partial recycle and reuse of wastes, and installation of a small pretreatment system; or implement pollution prevention techniques to create a closed-loop system that would provide 100 percent recycling and reuse of materials. After a technical and economic evaluation, the company decided the third option, a closed-loop system, was the most cost-effective alternative. The new system includes the following features (Figure 3) : All water phases of the product formulation process are batched in the same tank, thus precluding the need for washouts between batches. Leftover formulations are saved for the next batch. 178 August/September 1993

5 ~ hot Deionized water is used for tank washouts when a formula change is required. (The washout also is saved for the next batch.) Leftover active ingredients are saved for the next batch. The schedule for batching and formulation rotates compatible products to maximize the reuse of leftover washouts and active ingredients. These modifications have enabled the company to eliminate discharges to the sewer. By implementing changes that involved relatively low first-time costs, the company also has been able to realize savings in operating expenses. Paint stripping and metal finishing. Company B, which employs only three people, strips paint off old automobiles by using basic metal-cleaning and paint stripping techniques and pre pares the surface for repainting. Before pollution prevention measures were implemented, paint was stripped in a 9,Wgallon tank containing a caustic solution heated to between 110 degrees and 120 degrees Fahrenheit Car parts were submerged in the tank. drip-dried over trenches and rinsed again in a separate area The facility also had a pickling tank containing a 20 percent solution of muriatic acid, which removed oil, dirt and oxide fi-om metal parts. Parts pickled in acid were rinsed in the same spray area as those dipped in caustic. After being stripped and cleaned, parts were immersed in a bath of 15 percent phosphoric acid, which provided a good surface for paint bonding. Caustic cleaning was the main operation; muriatic and phosphoric acid treatment were intermittent. None of the facility's tanks was contained; all drippings and spills were wasted to the sewer. Spent caustic and acid solutions were discharged to trenches, where they neutralized each other. Accumulated solids were removed manually from the trenches. Rinses contained chromium, zinc and, on occasion, high levels of lead fi-om paints. Wastewater discharges ranged from 3,000 to '7.000 gallons per day; no treatment was provided prior to Toncompliance at the facility was attributed primarily to the lack of a waste management plan for reducing the level of heavy metals in rinsewater discharged to the sewer. The company was directed through a probation order to assess and resolve its noncompliance problem. To attain compliance, the company had to conduct an industrial waste survey and implement a pollution prevention plan. The company evaluated its processes and identified two waste management options: install an end-of-pipe pretreatment system to treat approximately 5,000 gallons per day of wastewater containing heavy metals; or install and implement pollution prevention techniques. After conducting an economic and technical evaluation, the company chose the second option (Figure 4). Key aspects of the pollution prevention measures were as fn%ws: A 6,00@gallon static rinse tank was added as an intermediate step before spray rinsing. Spray rinsing is performed only if needed after rinsing in the static tank. Spent rinsewater rgcircuiates to the caustic tank as makeup. Tanks are contained to capture drip pings and spills. Liquid captured in the contained area is recycled to the solution tanks. In addition to the obvious environ- mental benefits, this small company has been able to avoid the cost of designing, constructing and operating a pretreatment system and the concomitant compliance liabilities. E Adriana Renescu is a source control engineer for the County Sanitation Districts of Orange County (Fountain Valley, Chlg). Margaret H. Nellor is the agency's source control managel: AugustfSeptember