Totally Chlorine Free Study Prepared by Brian Parsons, Process Engineer CSF November 29, 2016 1 Table of Contents: Section 1 - Executive Summary………………………………………………….…….page 3 Section 2 - Facility Description Site Overview ……………………………………………………………..page 4 Permit Requirements…………………………………………………..page 5 Performance against permit…………………………………………page 8 Section 3 – CSF Product Requirements Overview…………………………….page 11 Section 4 – Current ECF Bleaching Process……………………………………….page 12 Section 5 - Comparing ClO2 to its TCF Counterparts………………………….page 13 Section 6 – Market Study for TCF Product………………………………………..page 18 Section 7 - Estimated Cost for Conversion from ECF to TCF………………page 18 Section 8 – Conclusions……………………………………………………………………page 18 Section 9 – References…………………………………………………………………….page 19 2 Section 1: Executive Summary Section S12 of the Cosmo Specialty Fibers’ NPDES permit (WA 0000809) required the submittal of a “comprehensive analysis of converting to a totally chlorine free (TCF) bleaching process. This analysis must include complete technology conversion description, itemized cost to convert, detailed market outlook/viability for TCF product. The analysis must specify the capital cost to convert and the predicted product sales impacts and long term economic viability resulting from the conversion.” CSF has conducted a study on whether or not it can/should convert from elemental chlorine free (ECF) bleaching to totally chlorine free (TCF) bleaching. The facility has found that the conversion is not economically viable for the following reasons: Permit limits for AOX, TCDD, and TCDF have been achieved with the current ECF bleaching sequence. The TCF replacements for chlorine dioxide (ozone and peracetic acid) are not suitable for bleaching chemistry requirements of Cosmo Specialty Fibers’ production of dissolving pulp, due to their inability to achieve product purity due to either degradation of cellulose fiber (in the case of ozone) or the significantly slower removal of lignin from the pulp (in the case of peracetic acid). Dissolving pulp product specifications cannot be produced without Chlorine Dioxide. There is no market demand for TCF products in the Dissolving pulp businesses which Cosmo Specialty Fibers competes in. TCF bleaching is not considered AKART for producing pulp used in all of the industries supplied by Cosmo Specialty Fibers The capital costs for converting the facility to TCF is not reasonable and the increased operating costs associated with the new oxidants would significantly impact profitability. The proceeding sections of this document we will outline these issues in greater detail. 3 Section 2: Facility Description OVERVIEW: Facility Location Map History The mill is in Cosmopolis, Washington on the south bank of the Chehalis River. Weyerhaeuser constructed the mill in 1957 as a paper grade sulfite process pulp mill. In 1962, Weyerhaeuser started converting the mill to produce dissolving and specialty grade pulp. The mill is capable of producing 550 tons per day of dissolving and paper grade pulp. Weyerhaeuser continued to operate the mill until September 2006, when production shut down. The company mothballed the equipment the following year in anticipation of selling the mill. In August 2010, an investor group, The Gores Group purchased the mill from Weyerhaeuser and named it Cosmo Specialty Fibers. CSF resumed operation in May 2011. The company ended production of paper grade pulps the mill now produces dissolving pulp, specifically acetate, viscose, ether and other limited specialty grades. [1] Industrial Processes Cosmo Specialty Fibers is an acid bisulfite pulp mill. It produces dissolving pulp from softwood chips for a variety of customers around the world. Currently the facility incorporates the use of elemental chlorine free bleaching (ECF) to produce its pulp; this means, that it uses Chlorine Dioxide in the bleaching of its pulp. 4 Pulp production varies based on market demand. Cosmo uses a magnesium bisulfite cooking acid in its pulping process. The mill has nine batch digesters for cooking primarily hemlock wood chips. The pulp exiting the digesters goes into dump tanks and a multi-stage, countercurrent brown stock washer system. The mill bleaches the pulp using a sequence of caustic, oxygen, chlorine dioxide, and hydrogen peroxides. Cosmo processes the pulp in the machine building to make the final product. [1] The pulping process generates spent cooking liquid called “brown liquor.” The spent liquor, which contains lignin, separates from the pulp in a countercurrent washer system. The mill further processes the brown liquor in evaporators and concentrators to form the “red liquor” and then burns the red liquor in recovery boilers no. 1, 2, and 3 for energy. The mill recovers magnesium oxide and sulfur dioxides from the recovery boilers flue gas and reuses the chemicals to make more cooking acid. The facility supplements the remaining cooking acid by burning sulfur at the acid plant and adding magnesium to the process. [1] The mill receives its water from the City of Aberdeen’s industrial water supply at Lake Aberdeen. The water flows to Cosmo’s filter plant via an underground pipe. The filter plant processes the water for uses in the mill’s pulping and bleaching process, machine room, and power boilers. [1] PERMIT REQUIREMENTS: Federal and state regulations require that effluent limits in an NPDES permit must be either technology- or water quality-based. [1] Technology-Based Effluent Limits Technology-based effluent limits are either set by regulations or developed on a case-by-case basis. Federal effluent guidelines in 40 CFR 430 Subpart D set limits for the dissolving sulfite pulp subcategory. These guidelines defined the Best Practicable Technology (BPT) and were published in the Federal Register on November 1982 and March 30, 1983. In the December 17, 1986 Federal Register, the guidelines also define the Best Conventional Pollutant Control Technology (BCT) to be the same as BPT. Both BCT and BPT are dated more than ten years ago. For BCT and BPT older than ten years, Ecology needs to determine if the limits are still valid and equivalent to “all known available and reasonable treatment” (AKART). To determine AKART, Ecology considered three things: • The current treatment technologies compared to technologies available when the federal effluent guidelines were established. • The pollutants loading to the wastewater treatment system. • The treatment system’s capability of meeting the federal effluent guidelines. Federal effluent guidelines in 40 CFR 430 Subpart D defines best available technology economically achievable (BAT) for pentachlorophenol and trichlorophenol. Cosmo does not use chlorophenolic- containing biocides. Therefore, these guidelines do not apply were not used to set technology-based limit for these pollutants. [1] 5 EPA has not promulgated federal effluent guidelines for the bleaching process at dissolving pulp sulfite mills. Ecology used best professional judgment in consultation with the EPA Region 10 to determine technology-based limits and AKART for the bleach plant effluent. [1] AKART Determination with Respect to the Bleaching Process EPA has not indicated a date for the promulgation of the effluent guidelines to address the bleaching process at sulfite mills that produces dissolving pulp. Because such mills are unique, it is unlikely that new effluent guidelines will be promulgated in the near future. Therefore, Ecology made the AKART determination using the 1998 effluent guidelines for the sulfite specialty grade (40 CFR 430 Subpart E), and in consultation with EPA staff at Region 10 and headquarters. The use of the 1998 effluent guidelines is still appropriate because specialty grade has a high alpha cellulose content of 91 or above ISO brightness, close to the characteristics of dissolving pulp. [1] Available effluent guidelines define best available technology economically achievable (BAT) for several processes similar but not identical to the process used at Cosmo. The mill currently uses ECF technology, which consists of chlorine dioxide, oxygen delignification, and caustic wash to bleach dissolving pulp. Dissolving pulp is almost pure alpha-cellulose with far fewer impurities than paper and specialty pulps; this level of purity is more difficult and costly to achieve with totally chlorine free (TCF) bleaching. According to EPA, there are no mills using TCF technology to make the same products as Cosmo. Because no new or untried technology is used to define AKART, ECF with oxygen delignification continues to define AKART for a dissolving sulfite mill like Cosmo. [1] In the future, improved technology or changes in market demands or regulations may make TCF bleaching feasible. Therefore, Ecology required this TCF study be completed in the current permit cycle. [1] Technology-Based Limit with Respect to the Bleaching Process As of the date of this permit, the EPA has not promulgated effluent guidelines for the bleaching process of dissolving sulfite pulp bleaching. Until guidelines are promulgated, Ecology used the 1998 guidelines for specialty grade sulfite pulp (40 CFR 430.54). These guidelines represent AKART (see section above). The compliance point is at the bleach plant effluent. The guidelines specify monitoring and limits for chlorinated organic compounds, including dioxins, associated with ECF bleaching method. Table 11 contains BAT limits for each pollutant. The basis for specific pollutants are shown in the paragraphs below. [1]