### E-mail Correspondence with AF&PA (Sulfide Discharges – O’Shaughnessy)

From: "O'Shaughnessy, Niall" <noshaugh@rocktenn.com> Sent: Monday, June 13, 2011 8:00 AM To: Sabol, Elizabeth CC: Acker, Ken G.; Butler, Nina-Mary; Schwartz, Jerry Subject: FW: FW: Request for 2009 DMR Data Clarification

See the responses to you questions below. Let me know if you have any other questions or need clarifications on the answers below.

Niall O'Shaughnessy, PE RockTenn 3700 Crestwood Parkway Suite 850 Duluth, GA 30096 770-570-1607 (office) 770-361-7359 (cell) noshaugh@rocktenn.com

From: Elizabeth Sabol [mailto:Elizabeth.Sabol@erg.com] Sent: Wednesday, June 08, 2011 8:26 AM To: O'Shaughnessy, Niall Subject: RE: FW: Request for 2009 DMR Data Clarification

Niall,

As discussed on the phone, the following questions are liste d as follow-up to the respons es provided in early March 2011 regarding 2009 sulfide discharges at the facility.

For the sulfide discharges confirmed:

1. What processes at the facility contribute to the sulfid e discharges? Please explain why sulfide is used or a byproduct of this process. The mill uses a kraft pulping process. The kraft process uses a sodium-based alkaline pulping solution (liquor) consisting of sodium sulfide (Na 2 S) and sodium hydroxide (NaOH) in 10 percent solution. This liquor (w hite liquor) is mixed with the wood chips in a reaction vessel (digester). The output pro ducts are separated wood fibers (pulp) and a liquid that contains the di ssolved lignin solids in a solu tion of reacted and unreacted pulping chemicals (black liquor). The black liquor undergoes a chemical recovery process to regenerate white liquor for the fi rst pulping step. Overall, the kraft process converts approximately 50 percent of input furnish into pulp.

The kraft chemical recovery process consis ts of the following general steps:

Black liquor concentration Residual weak black liquor from the pulping process is concentrated by evaporation to form "strong black liquor.” After brown stock washing in the pulping process, the concentration of solids in the weak black liquor is approximately 15 percent; after the evaporat ion process, solids concentration can range from 60 - 80 percent. In some older facilities, the liquor then undergoes oxidation for odor reduction. The oxidation step is necessary to reduce odor created when hydrogensulfide is stripped from the liquor during the subsequent recovery boiler burning process. Almost all recovery furnaces installed si nce 1968 have non- contact evaporation processes that avoid these problems, so oxidation processes are not usually seen in mills with modern recovery furnaces. Common modern evaporator types include multiple effect evaporators as well as a variety of s upplemental evaporators. Odor problems with the kraft process have been the subject of control measures.

Recovery boiler The strong black liquor from the evaporators is burned in a recovery boiler. In this crucial step in the overall kr aft chemical recovery process, organic solids are burned for energy and th e process chemicals are removed from the mixture in molten form. Molten inorganic process chemicals (smelt) flow-through the perforated floor of the boiler to water-cooled spouts and dissolvi ng tanks for recovery in the recausticizing
step.

Energy generation from the recovery boiler is often insufficient for total plant needs, however, so facilities augment recovery boile rs with fossil-fuel-fired and wood-wastefired boilers (hogged fuel) to generate steam and often electricity. Industry-wide, the utilization of pulp wastes, bark, and other papermaking residues supplies 65 percent of the energy requirements of pulp and paper companies.

Recausticizating Smelt is recausticized to remove impurities left over from the furnace and to convert sodium carbonate (Na 2 CO 3 ) into active sodium hydroxide (NaOH) and sodium sulfide (Na 2 S). The recausticization procedure begins with the mixing of smelt with "weak" liquor to form green liquor, named for its characteristic color. Contaminant solids, called dregs, are removed from the green liquor, which is mixed with lime (CaO). After the lime mixing step, the mixture, now called white liquor due to its new coloring, is processed to remove a layer of lime mud (CaCO 3 ) that has precipitated. The primary chemicals recovere d are caustic (NaOH) and sodium sulfide (Na 2 S). The remaining white liquor is then used in the pulp cooking process. The lime mud is treated to regenerate li me in the calcining process.

Calcining In the calcining process, the lime mud removed from the white liquor is burned to regenerate lime for use in the lime mixing step. The vast majority of mills use lime kilns for this process, although a few mills use fluidized bed systems in which the reactants are suspended by upward-blowing air.

2. Are there any treatment technologies in place for the sulfide? There are no specific treatment technologie s in place for sulfide treatment, however, the wastewater is treated across the mill’s wastewater treatment ponds before being discharged.
3. Are both sulfide and flow measurements taken at the same location in the process? If not, is a smaller flow associated with th e sulfide discharge?

Yes. The sulfide and flow measurement repr esent the effluent being discharged to the receiving stream.

4. Please provide a description of Outfall 001.The effluent from the treatment ponds is routed through a 30-inch effluent pipeline where it is discharged subsurface into the Pee Dee River. The Pee Dee River has a daily minimum flow of 673 cfs and a minimum mean flow of 3,480 cfs (1996 thru 2010). The effluent sample is collected from the wastewater wh ere it enters the 30- inch pipeline. Flow is measured using a venturi flow device in the pipeline.
5. Are the sulfide concentrations reported in 2010 similar to the 2009 concentrations?

Yes.

I appreciate your timely response to the questions listed above. Also, please call me directly (703-633-1659) if you have any questions or to discuss the answers.

I look forward to hearing from you.

Thanks, Elizabeth

Elizabeth A. Sabol Environmental Engineer Eastern Research Group, Inc. 14555 Avion Parkway, Suite 200 Chantilly, VA 20151 elizabeth.sabol@erg.com Phone:703-633-1659