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HomeMy WebLinkAboutNC0084620_Memo_Procedure for Development of NPDES Limits_19861003 1 � zCQ£ Jt f State of North Carolina Department of Natural Resources and Community Development Asheville Regional Office James G. Martin, Governor S. Thomas Rhodes, Secretary DIVISION OF ENVIRONMENTAL MANAGEMENT WATER QUALITY SECTION October 3 , 1986 MEMORANDUM TO: Steve Tedder, Supervisor Technical Services Meg Kerr Technical Services Randy Dodd Technical Services THROUGH: Forrest R. Westall Water Quality Regiona visor FROM: Michael R. Parker, Environmental Specialist-Affi�' Asheville Regional Office SUBJECT: Procedure for Development of NPDES Permit Limits for The Feldspar Corporation, Indusmin, Inc. , International Minerals and Chemical Corporation and Unimin, Corporation Mitchell and Avery Counties Attached to this memo is the procedure used to develop the fluoride and total suspended solids limits for the Feldspar Mining Industries in Mitchell and Avery Counties. It is requested that new wasteload allocations be prepared in accordance with the proposed limits . If you have questions, please call Mr. Westall or myself at 704/253-3341. MRP: ls Enclosure Interchange Building. 59 Vi%oodfin Place, P-O. Box 370. Asheville, N.C. 28802-0370• Telephone 704-253-3341 1n Fnn.l (lnru•-nnin artinname A.tu- Fmnlrn7•r � I PROCEDURE FOR DEVELOPMENT OF NPDES PERMIT LIMITS FOR THE FELDSPAR CORPORATION, INDUSMIN, INC. , INTERNATIONAL MINERALS AND CHEMICAL CORPORATION AND UNIMIN, INC. Discussion As a result of the reduction of total 'available fluoride (Fl) allocation wasteload to the river, the addition of another F1 user, and changes in production figures since allocations were made previ- ously, the Asheville Regional Office developed a questionnaire on process activities to be completed by each company discharging F1 to the North Toe River to assist in a new allocation effort. The results of that questionnaire will be used to develop individual allocations of fluoride for each facility. Confidentiality of the ore production was requested by each company. This information is on file in the Central Office. The objective of this process is simple, but the mechanics are difficult. The Environmental Management Commission has a policy of providing equivalent allocations to each discharge affecting the same water quality limited stream segment. For a more clearly defined equivalent allocation example, let us look at HOD If two dis- charges to the same segment are water quality limited (more restric- tive than minimum treatment requirements (i.e. secondary for domestic-type wastes and Environmental Protection Agency (EPA) guideline requirements for industrial process wastes) ; then allocations are set by equivalent reductions in minimum treatment requirements. For illustration, say one is domestic and the other discharge is composed of process industrial wastewater, then the BOD in the domestic is reduced equivalently from secondary levels and the process reduced the same percentage from'the applicable EPA guideline allowance until dissolved oxygen standards are complied with. Equivalent allocations is a concept related to riparian rights. Typically, riparian issues revolve around water use, however, in developing wasteload allocations to a common receiving stream, assimilative capacity is the resource available. Each allocation must allow that qualified user a rightful share of the resource. Since the resource is fixed in size, then the agency responsible for allocation must find some way to distribute the capacity in a manner that equivalently maintains each user' s right. A qualified user in this respect is the riparian property owner with legal access to the resource. It is important to recognize that assimilative capacity as a riparian commodity is not necessarily related to water use from the stream where a user needs to discharge waste. In fact, because of the nature of assimilative capacity, its allocation cannot be based upon the quantity of water used. It would be extremely unfair and not reflective of relative treatment burden to give a smaller alloca- tion to a user that for example recycles wastewater in the production process. The amount of final product produced would be a much better indicator. This same reasoning must apply when considering that a -2- user' s water supply may be relatively independent of the surface waters where treated wastewater would be discharged (i.e. well, lake on a tributary, public water system) . Riparian rights are also considered to be available to all qualified users (those with legal access) . As a result, property owners that have not in the past exercised their right to a particular aspect of riparian resources such as fluoride assimilative capacity cannot be refused that right just because they chose not to use it in the past. However, "new source" discharges have, within the EPA guideline process, been treated somewhat differently because of treatment technology avail- ability and the opportunity with new construction to incorporate current environmental control systems. This provides some basis for adjusting the allocation for new users but not for denying one. With the respect to the issue of riparian rights, the allocation process presented here will consider a user' s right to the resource under review, that being assimilative capacity. In the situation under review on the North Toe River, there are no approved EPA guidelines; therefore, the beginning basis must be developed. With the objective of a fair and equitable reallocation for each user, the factors used to set the allocations must be stable -and consistent. The factors must not reward poor operation or inefficient production but, must reflect the burden of removal accurately. With these criteria it is possible to eliminate several factors provided in the questionnaires. First, total raw ore feed tonnage on site is an inappropriate factor to use. Total feed tonnage does not necessarily reflect a representative comparison of how much fluoride wastewater will be produced. In addition and, similar in some respects, the feed tonnage to operations using fluorides is not an appropriate factor because it may improperly give differing F1 allocations when comparing several operations just due to process control activities within feldspar or guartz production. Specifically, if one company can render higher feldspar per ton of feed to the process, using feed tonnage would therefore cause that plant to receive a relatively lower allocation of F1 even through actual finished product could be equal to or greater than the other plant. Without question, the factor most appropriate for projecting fluoride allocations is finished feldspar and quartz products. Finished product figures are far and away the favored factor in EPA' s guidelines. The basic concept of using production is attractive in itself. Across a particular manufacturing category there is typic- ally variation in production techniques, waste treatment technology, management, market, and many other factors. The company that can apply the most effective use of raw materials, develop or locate in good market situations, and effectively comply with federal and local laws is going to prosper. By using finished product figures as the basis for wastewater controls, regulatory agencies are allowing the other market factors to function freely. It is not the responsi- -3- bility of environmental agencies to develop controls which adjust market factors. The previous discussion clearly illustrates why exact quantities of chemicals used in a process should not be an allocation factor, but it is important to briefly review the use of hydrofloric (HF) acid in feldspar and high purity quartz production. The use of this chemical is a critical factor in determining a relative weighting factor for feldspar verses quartz production. There is considerable variability in the amount of HF each company uses or projects it will use to process quartz. This is a reflection of two basic factors: 1) variations of process feeds and 2) a lack of actual operating knowledge about the process. The second factor is certainly an important issue in developing a F1 wasteload credit for quartz production. Only IMC is today producing high purity quartz. Both Feldspar and Unimin have fairly solid plans underway to install quartz production. Even considering variability in production, it is certain that the reliability of the data pro- vided from a firm already producing a product is higher than that of a company not producing the same product. in this same respect, the confidence placed in projections from a company on the verge of adding the process will be higher than that placed in figures from a company in the initial stages of developing a quartz production program. This might be better illustrated by looking at the quartz data in the following table: Quartz Production Information Final Pro- Gals. Quartz Feed HF Solution duction-- HF/tons Tonnage Used % Actual HF Quartz Quartz Facility tons/mo. gal/mo. In Solution tons/mo. Produced Feldspar 1910 24000 70 1150 20.8 Indusmin 6424 327000 70 4800 68.1 IMC 3319 30135 70 2766 10. 9 Unimin 1955 47500 70 1750 27 .1 Clearly, both the level of quartz output and the HF needed as provided by Indusmin is out of proportion to the other facilities. Therefore, those figures should not be used in making a weighting factor for quartz production. -4- In producing a final allocation factor, it is necessary to weight quartz production higher than feldspar production. Even though HF is used in the quartz process to "polish" or increase quartz purity, HF used per ton of product is much higher for quartz production than for feldspar production. Thus, fluoride waste from the quartz operation will contain higher quantities of F1, and therefore, represent a greater treatment burden. To develop the weighting factor, the feldspar data must be examined: Feldspar Production Information Gal HF (70%) Feed Tonnage Feldspar Feed Feldspar Per Ton to Feldspar Tonnage HF Used Finished Feldspar Produced Facility tons/Mo. gal/mo. tons/mo. Produced Ratio Feldspar 34233 2252 21181 0.11 1.6 Indusmin 24372 2070 17043 0.12 1.4 IMC 22003 3190 10710 0.30 2.1 Unimin 8833 1585 5300 0.30 1.7 Currently, only Unimin is not producing feldspar. However, because HF used and the feed tonnage to production tonnage ratio is close to those shown for the other three companies, the UNIMIN information will be considered in developing a weighting factor. HF used per ton produced for feldspar averages 0.23 gal/ton (0.11 to 0. 30 range) . For quartz production this same factor averages 19.6 gal/ton (range 10. 9 to 27.1, excluding the Indusmin information) . On the basis of this comparison and without respect to water use, significantly more fluoride waste is created for every ton of high purity quartz produced than is produced for every ton of finished feldspar. Thus, when dividing the available fluoride wasteload, a greater amount of fluoride (mass) should be allowed per ton of high purity quartz than per ton of finished feldspar. To decide upon a weighting factor for quartz production, it will be necessary to examine several issues. Simply applying the HF use ratios would result in what may be an excessive weighting factor-- 19. 6 divided by 0.23 equals 85 . 2 using the range of HF to quartz produced ratios, 10 . 9 to 27 .1, and the HF to feldspar produced ratios, 0.11 to 0. 30 , a "calculated" weighting factor ranges from 246 to 36. This shows a variation of almost 7 to 1. It is also clear that some of the waste handling technologies available for dealing with fluoride wastewater apply to both the feldspar and quartz waste streams. Recycle of fluoride contaminated water is an option that is relatively independent to fluoride concentrations, provided that wastewater containing fluoride is reused only in conjunction with fluoride processes (fluoride interference with other ore processing activities) . Therefore, while the waste handling demands for pure quartz are higher than for feldspar, that demand is likely to be lower than indicated by HF use information. Another factor available that points to this conclusion is that IMC which has the only operat- ing high purity quartz system, also has the lowest mass discharge of three facilities. It is true, however, that IMC' s wastewater control system represents what the Regional Office considers the standard for the industry. What these points show is that there are technologies which can, when applied with a strong management commitment, effec- tively reduce the quantity of fluoride released to the receiving waters. The final issue that must be discussed in recommending a weight- ing factor, is certainly equal to those just noted: i.e. ,the real world impact of the facilities receiving the allocations. In this matter we are dealing with four separate industrial corporations involved (or soon to be involved) as competitors in the same busi- ness, all located in the same general area, and all sharing a common riparian resource. Real and perceived conflicts make negotiating very difficult. Add to this a common view from all the companies that the fluoride standard is too restrictive and the recent emer- gence of the fourth competitor and you have a sensitive environment in which existing allocations must be reduced. The only way to examine this aspect of the allocation process is to calculate fluo- ride distributions for a variety of weighting factors. In doing so it will be necessary to provide the distributions over the entire range of near term configurations: Configuration I - Unimin Corporation not producing feldspar or quartz. The Feldspar Corporation operating without the planned high purity quartz facility, Indusmin at current feldspar production, and IMC producing feldspar and high purity quartz at current levels. Configuration II - Unimin Corporation not producing feldspar or quartz, The Feldspar Corporation operating with the high purity quartz facility and Indusmin, Inc. and IMC as described in I. Configuration III - Unimin Corporation producing feldspar and quartz, and other three companies as described in I. Configuration IV - Unimin Corporation as in III, The Feldspar Corporation producing high purity quartz and the other two companies as described in I. -6- Configuration V - Unimin Corporation as in III, The Feldspar Corporation and Indusmin, Inc. producing high purity quartz and IMC as described in I. Configuration VI - The Feldspar Corporation, IMC, Indusmin, Inc. and Unimin Corporation as described in V and Indusmin, Inc. with a 50% expansion of the feldspar plant. The process in developing a specific allocation can be described as follows: A. Calculate an allocation factor (Af) for each facility within a specific configuration: Af = F + Wf xQ where: Af = Allocation factor, F = Finished feldspar in tons per month (information supplied by the company) , Wf = Weighting factor for quartz production, Q = Finished high purity quartz, tons/Mo. B. Project a percentage share (PS) of available fluoride for each facility under each configuration. PS = Af x 100 SUM Af where: SUM Af = sum of all four Af' s for a particular configuration. C. Calculate the specific fluoride allocation (A-lbs/day) for each company. A = PS xAW 100 where: AW = Available wasteload to North Toe River = 574 lbs/day. -7- For comparison purposes the following information is provided: Facility Fluoride Information Fl Dis- charged Maximum Fl Current % Of Monthly % Of Most Current % Of Facility Permit Limits Total 1985-86 Total F1 Allocation Total Unimin Feldspar 279.1 38 256 38 218 38 Indusmin 220.3 30 261 39 172 30 IMC 235.0 32 160 23 184 32 All Figures Monthly Average lbs/day *Unimin projects 125#/day -8- Fluoride and Quartz Production Summary Finished Feldspar Finished Quartz Facility tons/mo. tons/mo. Unimin 5300 1750 r� Feldspar 21181 1150 Indusmin 17043 ( 25443* ) 500� IMC 10710 2766 *50% expansion at Indusmin. Comparison Wasteloads Under Configuration I Facility AF PS M A ( #/day) Wf = 1 Unimin 0 0 0 Feldspar 21181 41 235 Indusmin 17043 33 189 IMC 13476 26 150 51700 100 574 Wf = 85 Unimin 0 0 0 Feldspar 21181 7 40 Indusmin 17043 6 34 IMC 245820 87 500 284044 100 574 Wf = 6 Unimin 0 0 0 Feldspar 21181 32 183 Indusmin 17043 26 149 IMC 27306 42 242 65530 100 574 -9- Comparison Wasteload Under Configuration IV Wf = 1 Unimin 7050 12 69 Feldspar 22331 37 212 Indusmin 17043 28 161 IMC 13476 23 132 59900 100 574 Wf = 6 Unimin 15800 18 103 Feldspar 28081 32 183 Indusmin 17043 19 109 IMC 27306 31 179 88230 100 574 These five comparison allocation distributions are presented as illustration of the effects of different weighting factors (Wf ) . In reviewing this issue, the Division of Environmental Management staff examined distributions over all four configurations with Wf ' s of 1 , 2 , 3 , 6 , 10 , and 85 . In comparing all these figures with the Facility Fluoride Information table and considering all the issues disct.ssed in this report, it was concluded that a Wf of six ( 6 ) reprE!sented a reasonable weighting of quartz production fluoride wastE. burden and produces a fair fluoride allocation distribution that is achievable with existing technologies . It is clear from the compE.risons presented that the range of possible weighting factors reprE'sents , at the low end, an unfair situation to quartz producers and z.t the high end an unrealistic disruption in the previous alloca- tion pattern. A value of six for Wf is something of a middle ground position, providing each user a piece of the allocation pie large enough to permit compliance. In applying this approach there are some issues which must be addressed. Permits should not be based on projected production activities , but revisions to the distribution of Fl allowable should be adjusted when the new process is added ( i . e . configuration shifts ) . Initially, no high purity quartz production at Feldspar, Unimin or Indusmin will exist, and the allocation would not change until these processes came on line. Because Unimin does not now produce feldspar, no allocation for Fl would apply until such produc- tion exists . The following is a table showing allocation with Wf= 6 : Allocations Proposed Facility AF PS $ A ( #/day} Configuration I Unimin 0 0 0 Feldspar 21181 32 183 Indusmin 17043 26 149 IMC 27306 42 242 65530 100 574 Configuration II Unimin 0 0 0 Feldspar 28082 39 224 Indusmin 17043 23 132 IMC 27306 38 218 72431 100 574 Configuration III Unimin 15800 19 109 Feldspar 21181 26 149 Indusmin 17043 21 121 IMC 27306 34 195 81330 100 574 Configuration IV Unimin 15800 18 103 Feldspar 28081 32 183 Indusmin 17043 19 109 IMC 27306 31 179 88230 100 574 Configuration v Unimin 15800 17 98 Feldspar 28081 31 178 Indusmin 20043 22 126 IMC 27306 30 172 91230 100 574 Configuration VI Unimin 15800 16 92 Feldspar 28081 28 161 Indusmin 28443 29 166 IMC 27306 27 155 99630 100 574 -11- Unimin Corporation' s TSS effluent limitations will remain 20 mg/l daily average, 30 mg/l daily maximum until the Company starts to produce feldspar. The limits will then change to 707 lbs/day and 1414 lbs/day daily average and daily maximum. These limits were developed using the EPA draft development document - Mineral Mining and Processing Industry. 589 tons x 0.6 lb x 2000 lbs = 707 lbs day of raw ore 1000 lbs. product ton day of TSS Effluent limitations for TSS, pH and turbidity and flow for The Feldspar Corporation, Indusmin, Inc. and IMC are the same as those limits proposed in the last wasteload allocation dated May 5, 1986. A copy of the proposed effluent limits for Configurations I - VI for each company is attached.