Project XL Progress Report Molex Incorporated In 1995, the U.S. Environmental Protection Agency (EPA) embarked on a series of innova- tive initiatives in an effort to test new ways to achieve greater public health and environmental protection at a more reasonable cost. Through Proj ect XL, which stands for excellence and Leadership, EPA enters into specific proj ect agreements with public or private sector spon- sors to test regulatory, policy, and procedural alternatives that will produce data and experi- ences to help the Agency make improvements in the current system of environmental protec- tion. The goal of Proj ect XL is to implement 50 proj ects that will test ways of producing superior environmental performance with improved economic efficiencies, while increasing public participation through active stakeholder processes. As of January 200 1 , EPA has reached its goal of 5 0 proj ects in the implementation phase. EPA Proj ect XL Progress Reports provide overviews of the status of XL proj ects that are implementing Final Proj ect Agreements (FPAs). The progress reports are available on the Internet via EPAs Proj ect XL Web site at http://www.epa.gov/Project XL. Hard copies may be obtained by contacting the Office of Policy, Economics, and Innovation's (formerly the Office of Reinvention) Project XL general information number at (202) 260-5754. Additional information on Proj ect XL is available on the Web site or by contacting the general information number. The information and data presented in this Progress Report is current as of January 200 1 . Background Molex Incorporated (Molex) is a multinational company that operates 47 facilities world- wide, in manufacturing, electroplating, metal stamping, plastic molding, and fiber optics. Molex electroplates coatings of nickel, copper, and tin and lead metals on substrate materials for a variety of manufacturing purposes. The process generates large volumes of wastewater containing metal contami- nants, which are subsequently captured in wastewater treatment systems and become classified as hazardous waste under the Resource Conservation and Recovery Act (RCRA). Molex previ- ously operated a wastewater treatment system that combined the wastewater streams from nickel, copper, and tin and lead plating processes. These Molex XL Project" Lincoln' Nebraska Major Milestones July 11, 1995 Molex XL Proposal Submitted s August?, 1998 Nebraska DEQ Temporary Variance Issued s August 11, 1998 Final Project Agreement Signed February 2001 Expiration of Nebraska DEQ Temporary Variance ------- MolexXL Project 1-31-01 wastestreams were treated in a single wastewater treatment process that generated a hazardous multiple-metal waste material from which only one of the metals could be recovered, with the rest disposed. Molex switched to a process that segregates the wastewater streams from the plant's multiple electroplating processes and treats each one separately. Therefore, Molex recovers metal contaminants separately, reduces the amount of metal that would otherwise be disposed of in RCRA-regulated landfills or released to the environment at secondary smelters, and reduces metal-contaminant levels in the effluents discharged from the facility's wastewater treat- ment systems to Lincoln's publicly owned treatment works (POTW). In its XL proposal, Molex requested a variance from hazardous waste regulations in order to reduce the costs of storing and shipping these wastes to make it more cost-efficient to recover metals from electroplating wastestreams. Molex believes that its new segregated wastewater treatment system results in superior environmental perfor- mance through a reduction in the amount of metals discharged to Lincoln's POTW, as well as through an increase in metals recycling. Operational process lines were changed to generate separate treatment sludges for nickel, copper, and tin/lead that are classified as hazardous waste under the Nebraska Department of Environ- mental Quality (NDEQ) Hazardous Waste Management Program. Through these operational process changes, the Molex XL proj ect seeks to provide superior environmental performance by: • reducing the amount of metals loading in the effluent discharged to Lincoln's POTW; • increasing the level of metals reclamation or recycling; and • reducing the amount of material that would otherwise require landfill disposal. The segregated treatment system, however, costs more to operate than a combined treatment system. Addition- ally, the segregated system results in increased costs from compliance with current regulations for handling the resultant sludges. By providing the facility with a temporary variance from classifying nickel, copper, and tin/lead sludges as a solid waste, the Molex proj ect is helping to financially justify the continued operation of the segre- gated system. This temporary variance, which was issued by NDEQ on August 7,1998, allows Molex to handle the storage and shipment of these non-precious metals sludges at substantially reduced costs for two years. The variance was set to expire on August 7,2000, but has been extended an additional six months. This extension will allow Molex to complete its final report. Molex estimates that the recovery of non-precious metals under the former combined processing system costs approximately $14,500 annually. Under the new system, Molex anticipates receiving an annual income of more than $7,600 from the sale of the separated, non-precious metals-bearing sludges, and benefiting from a net annual savings in waste management costs of more than $22,000. The Experiment The Molex proj ect tests whether regulatory flexibility through a variance from hazardous waste regulations will lead to a reduction in the costs of storing and shipping these wastes and an increase in the rate of metals recov- ery from the multiple wastestreams the proj ect generates. The Flexibility As an incentive to achieve superior environmental performance at Molex's Lincoln facility, EPA and the NDEQ are providing more flexible and cost-effective processes for regulatory management. The statutory programs, and the EPA offices administering the programs, affecting the Molex XL project are: • Resource Conservation and Recovery Act (RCRA) programs administered by EPA's Office of Solid Waste; ------- MolexXL Project 1-31-01 • Pollution Prevention Act (PPA) programs administered by EPA's Office of Prevention, Pesticides, and Toxic Substances; and • Federal Water Pollution Control Act (FWPCA) programs administered by EPA's Office of Wastewater Management. EPA, pursuant to RCRA Section 3005(b), has authorized NDEQ to carry out Nebraska's Hazardous Waste Management Program in lieu of the Federal program. Under this authority, NDEQ issued a variance to Molex granting the facility a temporary exemption from the classification as hazardous waste of segregated sludges generated during wastewater treatment. Without this variance, the sludge materials would be subj ect to NDEQ generator requirements for storage and shipment of hazardous wastes. Sludges from the former combined treatment system at Molex's Lincoln facility contained copper, nickel, tin, lead, and gold. The sludges' gold content allowed Molex to handle the combined treatment sludge as recyclable materials from which precious metals are reclaimed, under Title 128, Rules and Regulations Governing Hazard- ous Waste Management in Nebraska, Chapter 7, Section 010. Sludges generated at the upgraded facility, however, do not contain precious metals and no longer qualify under the recyclable precious metal exclusion. By obtaining approval from the NDEQ under RCRA to classify its segregated process sludge as a "partially reclaimed" material rather than as a hazardous waste, Molex can ship the sludges using common carriers, rather than hazardous waste carriers that are subj ect to additional regulations for transportation, storage, and disposal (TSD) facilities under RCRA. Additionally, Molex is permitted to ship the hazardous materials on an as-needed basis, rather than every 90 days as required for hazardous waste. On July 10,2000, Molex requested a two-year extension of the temporary variance that had remained in effect for two years and was set to expire August 7,2000. In the request for this extension, Molex noted that it is expanding the production area of the plating department at its facility. This expansion, Molex stated, may offer an opportunity to continue to gather data under a greater process flow. In response, on August 2,2000, EPA and NDEQ issued a six-month extension of the variance. The additional six months will allow Molex to com- plete the final report. After reviewing Molex's final report, EPA and NDEQ have the option to issue an addi- tional two-year variance. The final data will be examined to determine the effect that separate treatment of Molex's wastestreams has on metal content in wastewater effluents. Data gathered will also be examined to demonstrate whether the segre- gated system produces a recyclable sludge with market value. Ultimately, data gained through this proj ect will provide the information necessary to assess whether modifications to national or state performance standards are possible. This XL project supports RCRA, PPA, and Nebraska Hazardous Waste Management Program's goals of resource recovery and conservation. Specifically, the project results in recycling of metal sludges by recycling facilities, which will decrease the need for mining of ores or other virgin materials. This will result in the conser- vation of mineral resources and a reduction in the amount of materials that would otherwise be sent to a landfill. The Molex XL proj ect also supports the goals of the FWPCA and Nebraska Surface Water Quality Standards to restore and maintain the chemical, physical, and biological integrity of the nation's and state's waters. Specifi- cally, the proj ect reduces the amount of metals being loaded into the City of Lincoln's POTW, thus reducing metals discharged from the POTW into surface waters and the amount of metals-bearing sludges that are ultimately sent to a landfill. Additionally, the reduced loading gives the POTW a reserve treatment capacity, reducing the need to replace or enlarge the publicly financed facility. ------- Molex XL Project 1-31-01 Promoting Innovation and System Change Proj ect XL provides EPA opportunities to test and implement approaches that protect the environment and advance collaboration with stakeholders. EPA is continually identifying specific ways in which XL proj ects are helping to promote innovation and system change. The innovations and system changes emerging from the Molex XL project are described below. UsingaRCRA Solid Waste Variance to Encourage Recycling. Under the RCRA regulations, regulated entities may petition EPA to exempt or exclude materials from classification as a solid or hazardous waste. Molex is testing the use of a solid waste variance for RCRA-listed wastes to encourage metals recycling and reduce solid waste generation. The environmental performance and economic feasibility of the Molex proj ect could serve as a benchmark against which other potential requests for temporary variances may be measured. Project Commitment Summary This table and the environmental performance section that follows summarize progress in meeting the commit- ments described in the FPA and temporary variance for the Molex Facility in Lincoln, Nebraska. Commitment Status Waste Analysis and Reporting Conduct and submit results of initial waste analysis on each of the three sludges (nickel, copper, and tin/ lead) for toxicity characteristic leaching procedure (TCLP), toxic metals, pH, and moisture content, in accordance with the variance and Attachment B of the FPA. Analytical results were included in the initial baseline report, which was submitted to NDEQ and EPA on November 17, 1998. Conduct and submit results of waste analysis on each of the three sludges for chlorine, sulfides, antimony, beryllium, thallium, heating value, and total organic carbon (TOC), in accordance with the FPA. Analytical results (with the exception of TOC) were submitted to EPA on September 15,1998. If waste analysis indicates that TOC exceeds 500 parts per million (ppm) (by weight), submit data that prove that samples do not include greater than a 500 ppm total concentration of organic compounds, in accordance with the FPA. Analytical results on TOC were included in the first quarterly report, which was submitted to NDEQ and EPA on December 4, 1999. Conduct waste analyses on each sludge shipment prior to reclamation of total copper, nickel, lead, tin, zinc; of pH; and of moisture content, in accordance with the variance and FPA. As of 1999, waste analyses has been conducted prior to each shipment. Provide an initial Baseline Report describing (1) the performance of the combined treatment system for the most recent 12-month period prior to implemen- tation of the segregated treatment system, and (2) productivity estimates of the segregated treatment system, in accordance with the variance and FPA. The initial Baseline Report was submitted to NDEQ and EPA on November 17, 1998. ------- Molex XL Project 1-31-01 Commitment Status Waste Analysis and Reporting (Continued) Submit quarterly reports to EPA and NDEQ every 3 months after submitting the initial baseline report describing current data for the segregated treatment system, in accordance with the variance and FPA. Provide a final report in accordance with the terms outlined in the variance and FPA. Maintain records of test results, waste analyses, and other variance conditions. Notify the NDEQ of the name, address, and facility contact for each facility to which material is sent for reclamation, and a description of anticipated pro- cessing. First quarterly report: December 4, 1998 Second quarterly report: March 4, 1999 Third quarterly report: May 27, 1999 Fourth quarterly report: August 7, 1999 Fifth quarterly report: November 11, 1999 Sixth quarterly report: February 1 1 , 2000 Seventh quarterly report: May 24, 2000 Eighth quarterly Report: September 7, 2000 Received by EPA November 13, 2000. Since 1 998, Molex has maintained a records man- agement system supporting terms of the variance. In 1 999, Molex began to notify NDEQ of each facility that receives material for reclamation. Waste Recordkeeping, Storage, and Transfer Maintain nonhazardous waste manifests identifying each specific shipment. Accumulate the nickel and copper sludges for no longer than 180 days before shipment, and store and transfer the tin/lead sludge in accordance with variance provisions. Molex began to maintain nonhazardous waste manifests for each shipment in 1 999. Storage conditions specified in the variance are being met by Molex; shipment of the segregated sludges began in 1999. EPA Commitments Determine need for additional sampling. EPA has determined that additional sampling and analysis will not be necessary for the duration of the temporary variance. Environmental Performance This section summarizes progress in meeting the environmental performance described in the FPA and tempo- rary variance for the Molex Facility in Lincoln, Nebraska. Note about the Baseline Data: In its Baseline Report Molex (1) collected data on the combined treatment system for the most recent 12-month period prior to implementation of the segregated treatment system, and (2) provided productivity estimates of the segregated treatment system. For the combined treatment system, the report presented data on the concentration and mass of metals in the effluent discharged to Lincoln's POTW, the volume of sludges generated and stored on site, the volume of sludges shipped to the recycler, and an analysis of the sludges. The report also estimated the productivity of the segregated treatment system. It is important to note that sludge volumes between the combined treatment process and the segregated treatment process are not strictly comparable, because the combined treatment sludges were dried but the segregated ------- Molex XL Project 1-31-01 treatment sludges were not. This section compares the estimated sludge generation rates from the Baseline Re- port, and actual sludge generation rates of the segregated treatment system. Data from 1999 were measured based on four Molex quarterly reports, which cover proj ect performance from August 7,1998, to August 7, 1999. Data from 2000 were measured based on four Molex quarterly reports, which cover proj ect performance from August 8,1999, to August 7, 2000. Copper Sludge Generation and Loading In the Baseline Report, Molex estimated that 13,376 pounds of copper sludge would be generated with the segregated treatment system. However, 1999 actual generation rates were 59 percent higher (21,242 pounds) than the estimated baseline. For 2000, Molex has generated 35,200 pounds of copper sludge, a 163 percent increase from the baseline data. Based on the Quarterly Reports, it is estimated that the use of the segregated system has resulted in decreased copper concentrations in the POTW's effluent by 66 percent in 1999 and 79 percent in 2000, com- pared to baseline. Nickel Sludge Generation and Loading In the Baseline Report, Molex estimated that 45,089 pounds of nickel sludge would be generated with the segregated treatment system. However, 1999 actual generation rates were 8.5 percent higher (48,928 pounds) than the estimated baseline. In 2000, a total of 60,684 pounds of nickel sludge have been generated. Based on the Quarterly Reports, use of the segregated system has resulted in decreased nickel concentrations in the POTW's effluent by 67 percent in 1999 and 82 percent in 2000. Tin/Lead Generation and Loading In the Baseline Report, Molex estimated that 12,863 pounds of tin and lead sludges would be generated with the segregated treatment system. Actual generation rates in 1999 were 34 percent lower (8,539 pounds) than the estimated baseline. However, in 2000, Molex has generated 16,614 pounds of tin and lead sludges. Based on the Quarterly Reports, use of the segregated system in 1999 resulted in estimated decreased concentrations of tin (98 percent) and lead (29 percent) in the effluent being discharged by the POTW. In addition, in 2000 the use of the segregated system has resulted in estimated decreased concentrations of tin (98 percent) and lead (44 percent) in the effluent. Copper Sludge Generation Rates For the Segregated Treatment System Baseline Estimate 13,376 0 10000 20000 30000 40000 50000 Pounds of Copper Sludge *This information is based on Molex's quarterly reports, which cover project performance from 8/7/98-8/7/99 **This information is based on Molex's quarterly reports, which cover project performance from 8/8/99-8/7/00 Nickel Sludge Generation Rates For the Segregated Treatment System Baseline Estimate 60,684 10000 20000 30000 40000 50000 Pounds of Nickel Sludge 60,000 70,000 *This information is based on Molex's quarterly reports, which cover project performance from 8/7/98-8/7/99 **This information is based on Molex's quarterly reports, which cover project performance from 8/8/99-8/7/00 Tin/Lead Sludge Generation Rates For the Segregated Treatment System Baseline Estimate 12,863 0 10000 20000 30000 40000 50000 Pounds of Tin/Lead Sludge *This information is based on Molex's quarterly reports, which cover project performance from 8/7/98-8/7/99 **This information is based on Molex's quarterly reports, which cover project performance from 8/8/99-8/7/00 ------- Molex XL Project 1-31-01 Estimated Reductions in Metal Concentrations in Effluent •Copper 1999 Actual * Copper 2000 Actual •Nickel 1999 Actual ** Nickel 2000 Actual *Tin 1999 Actual "Tin 2000 Actual •Lead 1999 Actual ** Lead 2000 Actual 66% 79% 67% 82% 98% 98% 29% 44% 20 40 60 80 100 Percent Reduction of Metals Concentrations This information is based on Molex's quarterly reports, which cover project performance from 8/7/98-8/7/99 **This information is based on Molex's quarterly reports, which cover project performance from 8/8/99-8/7/00 Volume of Metals Sludge Shipped to Recycler 134,988 Baseline Estimate Total Generation of Sludge In the Baseline Report, Molex estimated that the segregated treatment system would generate a total of 71,328 pounds of sludge, but 1999 actual generation rates based on the Quarterly Reports indicate that actual sludge generation rates were 10.3 percent higher (78,709 pounds) than the estimated baseline for the segregated system. In 2000, the total amount of metal sludge generated was 112,498, a 58 percent increase over the estimated baseline. Based on the Quarterly Reports, it is estimated that the segregated treatment system has resulted in an average 65 percent reduction in the concentration of copper, tin, lead, and nickel in the effluent discharged by the POTW in 1999 and an average 76 percent reduction in 2000. Sludge Recycling In the Baseline Report, Molex estimated that it would be able to recycle 71,328 pounds of metals sludges in a year. However, the Quarterly Reports indicate that between August 1998 and August 1999, a total of 78,709 pounds of sludge were senttotherecycler, 10.3 percent more than estimated. In addition, in 2000, a total of 134,988 pounds of sludge were sent to the recycler, 89 percent more than expected. Stakeholder Participation Molex worked to ensure that stakeholders were involved in the environmental design and impact assessment of its XL proj ect and had an opportunity to participate fully in proj ect development. The organiza- tions directly involved in negotiating the FPA included Molex, EPA, NDEQ, the Lincoln-Lancaster County Health Department, and the City of Lincoln. Meetings were held on August 24,1996, andOctober30,1996, to discuss the Molex XL proj ect proposal and develop the FPA. EPA received stakeholder comments on the implementation of the Molex XL proj ect following notification to the public on November 3,1997. While recognizing the potential benefits of Proj ect XL, organizations such as the Environmental Defense Fund and the World Resources Company expressed concern with specific aspects of the Molex XL proj ect. The issues of concern included apparent weaknesses in the administrative record with respect to baseline practices and historical records; determination of the com- modity-like nature of the various sludges; and the adequacy of follow-up waste testing, particularly with respect to TOC content. In response to these concerns, EPA gathered additional data required for the administrative record, conducted further analysis of the economic value of the generated sludges, and requested that Molex implement a more comprehensive sampling and analysis program. Meeting agendas and documents pertaining to FPA negotiations are available to the public through the State of Nebraska, EPA Region 7, and EPA Headquarters' Offices and are accessible via the Internet on the Proj ect 25000 50000 75000 100000 Pounds per Year 125000 150000 *This information is based on Molex's quarterly reports, which cover project performance from 8/7/98-8/7/99 **This information is based on Molex's quarterly reports, which cover project performance from 8/8/99-8/7/00 ------- MolexXL Project 1-31-01 XL homepage. The public has been notified since initiation of this project and invited to participate, and will continue to be informed through report dissemination during implementation of the project. Six-Month Outlook NDEQ and EPA will review analytical data and the final report provided by Molex in accordance with require- ments in the temporary variance and the FPA. Among the factors to be considered in any final variance determi- nation following the expiration of the existing temporary variance are: • the degree of processing the material has undergone and the degree of further processing that is required; • the value of the material after it has been reclaimed; • the degree to which the reclaimed material is like an analogous raw material; • the extent to which an end market for the reclaimed material is guaranteed; and • the ability to handle the reclaimed material in a manner that minimizes loss. Project Contacts • Paul Eckerson, Molex, (402) 475-1700. • David Doyle, U.S. EPA, Region 7, (913) 551-7667. • Mitch Kidwell, EPA Headquarters, (202) 260-2515. • Bill Gidley, NDEQ, (402) 471-4217. • Brian Gorman, NDEQ, (402) 471-8846. • Annette Kovar, NDEQ, (402) 471-3585. • Beth Mann, Lincoln/Lancaster County Health Department, (402) 441 -623 5. • Rick Shibata, City of Lincoln, (402) 441 -7961. Information Sources The information sources used to develop this progress report were (1) 1]\Q December 1999 Project XL Progress Report—Molex Incorporated (EPA 100-R-OO-OO11); (2) focus group discussions in December 1999 with representatives of Molex, EPA Regional and Headquarters staff, World Resources (a national environmental group), NDEQ, City of Lincoln, and local community stakeholders; and (3) Molex Proj ect XL quarterly reports through September 2000. On December 9,1999 EPAs Office of Policy, Economics and Innovation convened a two-hour focus group teleconference with representatives of the Molex Company, EPA Regional and Headquarters staff, World Resources Company, NDEQ, and the City of Lincoln. The purpose of the focus group was to gain partici- pants' opinions on the lessons learned and innovations resulting from implementation of the Molex XL proj ect. Comments from this focus group were incorporated into this report. Glossary Baseline: The measure by which future environmental performance can be compared. Delisting: The process of excluding from regulations a waste that EPA has defined as hazardous, if it can be shown that the waste no longer threatens human health and the environment. ------- MolexXL Project 1-31-01 Disposal: The discharge, deposit, inj ection, dumping, or placing of any solid or hazardous waste on or in the land or water. Effluent: Treated or untreated wastewater that flows out of a treatment plant, sewer, orindustrial outfall. Gener- ally refers to wastes discharged into surface waters. Electroplating: The electrodeposition of an adherent metallic coating upon an electrode for the purpose of securing a surface with properties or dimensions different from those of the base metal. Federal Water Pollution Control Act (FWPCA): The FWPCA of 1972 established the foundation of the current National Pollutant Discharge Elimination System (NPDES) program. This legislation and its subsequent amendments in 1976 and 1987 were enacted to address the direct connection between effluent (a point source) or runoff (a nonpoint source) and the water bodies that receive them. The 1976 amendment affirmed a legal agreement to control the growing problem of toxic discharges. In 1987, Congress amended the FWPCA again through the Clean Water Act (CWA) to address the inability of permits to meet the CWA goal of protecting swimming, fishing, and fish propagation. These amendments strengthened the ability of states to establish water quality standards. Final Project Agreement (FPA): The FPA outlines the details of the XL project and each party's commitments. The project's sponsors, EPA, state agencies, Tribal governments, other regulators, and direct participant stakeholders negotiate the FPA. Hazardous Waste: Byproducts of society that can pose a substantial or potential hazard to human health or the environment if improperly managed. Under the RCRA program, hazardous wastes are specifically defined as wastes that possess at least one of four characteristics (ignitability, corrosivity, reactivity, or toxicity), or appears on special EPA lists. Listed Wastes: Wastes that are considered hazardous under RCRA because they meet specific listing descrip- tions. Media: Specific environments—air, water, soil—that are the subj ect of regulatory concern and activities. Multimedia: Several environmental media, such as air, water, and land. Pollution Prevention Act (PPA): The Act that focuses on enhancing industry, government, and public attention on reducing the amount of pollution through cost-effective changes in production, operation, and raw- materials use. Pollution prevention also includes other practices that increase efficiency in the use of energy, water, or other natural resources, and protect our resource base through conservation. Practices include recycling, source reduction, and sustainable agriculture. Publicly Owned Treatment Works (POTWs): Publicly owned facilities that receive and treat sewage and/or wastewater from residences, commercial activities, and industries. Reclamation: Restoration of materials found in the wastestream to a beneficial use that may be for purposes other than the original use. Recycling: The separation and collection of wastes, their subsequent transformation or remanufacture into usable or marketable products or materials, and the subsequent purchase of those products made from recyclable materials. Resource Conservation and Recovery Act (RCRA): RCRA gives EPA the authority to control hazardous waste from "cradle-to-grave." This includes the generation, transportation, treatment, storage, and disposal of hazard- ous waste. RCRA also sets forth a framework for the management of nonhazardous wastes. RCRA enables ------- Molex XL Project 1-31-01 EPA to address environmental problems that could result from underground tanks storing petroleum and other hazardous substances. RCRA focuses only on active and future facilities and does not address abandoned sites. Sludges: Any solid, semisolid, or liquid wastes generated from a wastewater treatment plant, water supply treatment plant, or air pollution control device. Substrate: Material upon which electroplating coatings are deposited. Transportation, Storage, and Disposal (TSD) Facilities: Facilities engaged in the treatment, storage, or disposal of hazardous waste. Toxicity Characteristic Leaching Procedure (TCLP): A laboratory procedure designed to predict whether a particular waste is likely to leach chemicals into groundwater at dangerous levels. Variance: Government permission for a delay or exception in the application of a given law, ordinance, or regulation. Wastewater: The spent or used water from a home, community, farm, or industry that contains dissolved or suspended matter. Water Pollution: The presence in water of enough harmful or objectionable material to damage the water's quality. 10 ------- |