1 

### MEMORANDUM | 2 6 October 2012

TO 

### Tab Tesnau, US EPA ORCR FROM 

### Jason Price, Wiles Kase, and Eric Reker, Industrial Economics, Incorporated SUBJECT 

### Generation, Management, and Processing of Paper Processing Residuals

Pursuant to Technical Directive 1 issued under Work Assignment B

- 01, this memo summarizes information that IEc obtained on the generation and management of paper proce ssing residuals (PPRs) . Based on our review of the relevant literature and our contacts with industry representatives , this memo presents the following data:

 The quantity of paper processing residuals generated on an annual basis in the U.S.

 The portion of paper processing residuals burned as an energy source, distinguishing between onsite use and offsite use.

 The quantity of paper processing residuals managed through other (non

- fuel) end uses such as land application and landfilling.

 The type and level o f processing for paper processing residuals used as fuel . We obtained information on the generation and use of paper processing residuals from representatives of the American Forest & Paper Association ( AF&PA) and the Recycled Paperboard Technical Association (RPTA). 1 

### Based on an informal survey of their member companies, the se representatives provided the following information with respect to the generation and use of paper processing residuals:

 Genera tion of paper processing residuals : Paper recycling facilities generate between 450,000 and 600,000 tons of PPRs (including old corrugated cardboard ) per year (although these data are not for the most recent year and the amounts are likely to have changed with the increase in recycling). These values reflect the residuals generated by the initial screening process (i.e., to remove metals), materials that do not break down during processing (e.g., paper treated to repel water), and fibers too small to be re

- used. There are no definitive data on what portion of this material is old corrugated cardboard, but a broad array of types of recovered fiber, such as old magazines, old newsprint and office paper, are increasingly used at paper recycling mills as recove ry rates approach 70 percent of all paper produced.

1 The information provided in this section is based on personal communication with Tim Hunt of the AF& PA and Amy Schaffer of the RPTA, October 19, 2012. BACKGROUND

GENERATION AND USE OF PAPER PROCESSING

RESIDUALS2 

###  End uses: Roughly 30 percent of paper processing residuals (approximately 135,000 to 180,000 tons) are burned for their fuel value. Between six and ten companies currently burn paper processing residuals in 15 to 20 different mills. At mills that burn paper processing residuals as a fuel onsite, the percentage of this material burned ranges from 55 to 100 percent of the PPRs generated onsite . In additi on, a t some mills, paper processing residuals provide up to 20 to 25 percent of the total solid fuel energy consumed onsite. Thus, paper processing residuals represent a significant source of energy for these facilities. PPR s are not burned during solid fuel boiler downtime or when combustion conditions and fuel availability dictate a different mix of solid fuels to meet boiler performance characteristics. The 70 percent of PPRs that are not burned for energy are mostly landfilled, with minimal amounts u sed for land applications.

 On - site versus off

- site usage: Of the roughly 30 percent of PPRs burned as a fuel, a large majority is burned on site. The representative from the AF&PA estimates that no more than 5 percent of PPRs are burned offsite . As noted above, o nly 15

- 20 of the 100+ paper mills across the U.S. burn PPRs as fuel. Many facilities (particularly recycle mills) use natural gas in their boilers and are unable to use solid material as a fuel source. Unless an a rrangement can be made with anot her boiler in the area to use the material, the PPRs generated at facilities that use natural gas boilers are landfilled. IEc reviewed several sources related to the nature and extent of processing that is regu larly performed on PPR prior to use as a fuel, including public comments submitted to the EPA under the NHSM Rule, journal articles, and industry websites. Excluding public comments on the NHSM rule, limited information was readily available on the subjec t, primarily focusing on paper processing in Europe and the United Kingdom. We were able to obtain one peer reviewed journal article on the subject, which did not contain information on PPR processing in the US. However, the information in this article, wh ich focuses on processing in Europe, describes processing measures for PPR similar to those found in the public comments. In conducting this research, we identified processing information for both recycling process residuals and pulp & paper sludge, which are defined as follows:

 Recycling process residuals (RPR) : paper fiber that is unusable (due to impurities, fibers to o small for recycling process) resulting from the recycling process .  Pulp and paper sludge (PPS) : pulp and paper wastewater treatment res iduals . To summarize, various methods are used to dewater and appropriately size PPR for use as fuel. PPS generally requires more intensive processing than RPR, particularly dewatering. RECYCLING PROCESS RE SIDUALS 

### According to the public comment submitted to the EPA under the NHSM Rule Package by nine major industry representatives, including the AF&PA, the American Wood Council, and the Biomass Power Association, some processing occurs before burning PROCESSING OF PAPER PROCESSING RESIDUALS3 

### RPR for energy . 2 

### Processors generally use a slotted screen to select cellulosic fibers that are too small for paper production, which are considered to have adequate heating value. Some plants will then use hydraulic presses to squeeze unwanted moisture out of the resi duals before shredding the material to the optimal size for combustion. 3 

### The measures for processing of RPR described in AF&PA’s comment are corroborated in the literature we were able to obtain. The literature states that to select the fibers too small fo r paper production or the recycling process, plants use a slot screening mechanism. 4 

### Infrequently, some plants may apply a drying process to these residuals before firing them, but the minimal processing needed to convert these materials into valuable fuel is generally an attractive feature. 5

PULP AND PAPER SLUDG E (PPS) 

### Information submitted in the public comment from AF&PA mentioned above indicates that significantly more processing is required before PPS can be used as a fuel. The overwhelming majority o f pulp and paper mills remove water from PPS prior to use as a fuel (or in other applications), using belt and screw presses, steam heated filter presses, and sometimes steam heated rotary driers for additional dewatering. 6 

### Information submitted by one mil l describes the processing of PPS in its plant: “Process waters carry the fibers rejected by the screens and cleaners and the fines to the water treatment system. Gravity settling in the primary clarifier removes the solids from the process water. The set tled solids, called clarifier WWTR, are pumped from the clarifier to the filter press. Water is squeezed out of the WWTR and it is hauled to the fuel pile for the multi

- fuel boiler .” 7 

### Another mill process is as follows:

“ The mill generates combined primary and secondary WWTR using three parallel rotary screen thickeners (RSTs) followed by screw presses. The RSTs and screw presses are optimized to provide the highest possible solids content. The dewatered WWTR is stored on a pad, then transferred to the boil er fuel reclaim area, and

2 American Forest & Paper Association, et al. , public comments submitted on the Rule to Categorize Non - Hazardous Secondary Materials That Are Solid Waste (EPA - HQ - RCRA - 2008 - 0329) and Commercial and Industrial Solid Waste Incineration Units: Reconsideration and Proposed Amendments (EPA - HQ - OAR - 2003 - 011 9). Comment ID EPA - HQ - RCRA - 2008 - 0329 - 1946 - A1. February 21, 2012. P. 55. 3 American Forest & Paper Association, et al. , public comments submitted on the Rule to Categorize Non - Hazardous Secondary Materials That Are Solid Waste (EPA - HQ - RCRA - 2008 - 0329) and C ommercial and Industrial Solid Waste Incineration Units: Reconsideration and Proposed Amendments (EPA - HQ - OAR - 2003 - 0119). Comment ID EPA - HQ - RCRA - 2008 - 0329 - 1946 - A1. February 21, 2012. P. 55. 4 Gavrilescu, D. “Energy from biomass in pulp and paper mills.” Env ironmental Engineering and Management Journal , Vol. 7, No. 5, 537 - 546. September/October 2008. P. 540. 5 Gavrilescu, D. “Energy from biomass in pulp and paper mills.” Environmental Engineering and Management Journal , Vol. 7, No. 5, 537 - 546. September/Octob er 2008. P. 542. 6 American Forest & Paper Association, et al. , public comments submitted on the Rule to Categorize Non - Hazardous Secondary Materials That Are Solid Waste (EPA - HQ - RCRA - 2008 - 0329) and Commercial and Industrial Solid Waste Incineration Units : Reconsideration and Proposed Amendments (EPA - HQ - OAR - 2003 - 0119). Comment ID EPA - HQ - RCRA - 2008 - 0329 - 1946 - A1. February 21, 2012. P. 53. 7 American Forest & Paper Association, et al. , public comments submitted on the Rule to Categorize Non - Hazardous Secondary Materials That Are Solid Waste (EPA - HQ - RCRA - 2008 - 0329) and Commercial and Industrial Solid Waste Incineration Units: Reconsideration and Proposed Amendments (EPA - HQ - OAR - 2003 - 0119). Comment ID EPA - HQ - RCRA - 2008 - 0329 - 1946 - A1. February 21, 2012. P. 48.4 

### transported to the fluidized bed boiler, along with hog fuel, on a series of conveyors. ” 8 

### In their public comment submitted to the EPA under the NHSM Rule Package, Verso Paper Corp. states that they employ an activated sludge trea tment (AST) process and secondary holding tanks to separate out cellulosic fibers from wastewater. According to the comment:

“ After excess secondary sludge is removed from the treatment loop, at three of Verso’s mills it is mixed with primary sludge in ble nd tanks prior to being dried on belt presses to a suitable moisture level for burning or other uses. Sludge is introduced into the mills’ solid fuel feed systems by means of conveyers, where it becomes thoroughly mixed with other fuels in the conveyer sys tems before being introduced into the mills’ combination boilers. At one mill , primary sludge is dried separately by means of screw presses, while secondary sludge is dried using a belt press. The two fuels are fed separately by conveyers onto the mill’s m ain solid fuel conveyer, which transports the bark/sludge mixture to a surge bin. The fuel is passed through a “waste heat dryer,” where it is briefly exposed to boiler flue gas before being fed into the combination boiler.” 9 

### As with RPR, the literature w e were able to obtain corroborates the description of the level and type of processing of PPS provided in public comments. Gavrilecu (2008) states that maximum mechanical dewatering of sludge prior to combustion is essential. The paper also claims that rec yclers and paper processors may mix PPS with dryer secondary materials to improve energy output. 10 

### Increasingly, PPS will undergo fluidized bed combustion, as it works particularly well with the wet sludge produced in de

- inking mills. Gavrilescu states that , “in this process, air is bubbled through a bed of inert material (usually sand or limestone), which greatly improves the combustion process.” 11 

### Plants use varying processing methods for each type of PPS produced in “the common effluent treatment processes ” (de

- inking sludge vs. sludge from paper mill waste

- water treatment plants, effluent sludge, etc.). 12

8 Ame rican Forest & Paper Association, et al. , public comments submitted on the Rule to Categorize Non - Hazardous Secondary Materials That Are Solid Waste (EPA - HQ - RCRA - 2008 - 0329) and Commercial and Industrial Solid Waste Incineration Units: Reconsideration and Proposed Amendments (EPA - HQ - OAR - 2003 - 0119). Comment ID EPA - HQ - RCRA - 2008 - 0329 - 1946 - A1. February 21, 2012. P. 48. 9 Verso Paper Corp., public comments submitted on the Rule to Categorize Non - Hazardous Secondary Materials That Are Solid Waste (EPA - HQ - RCRA - 200 8 - 0329) and Commercial and Industrial Solid Waste Incineration Units: Reconsideration and Proposed Amendments (EPA - HQ - OAR - 2003 - 0119); and National Emission Standards for Hazardous Air Pollutants for Major Sources: Industrial, Commercial, and Institutional Boilers and Process Heaters: Reconsideration and Proposed Amendments (EPA - HQ - OAR - 2002 - 0058). Comment ID EPA - HQ - RCRA - 2008 - 0329 - 1942. February 20, 2012. P. 6 - 7. 10 Gavrilescu, D. “Energy from biomass in pulp and paper mills.” Environmental Engineering and Ma nagement Journal , Vol. 7, No. 5, 537 - 546. September/October 2008. P. 541. 11 Gavrilescu, D. “Energy from biomass in pulp and paper mills.” Environmental Engineering and Management Journal , Vol. 7, No. 5, 537 - 546. September/October 2008. P. 541. 12 Gavrilescu , D. “Energy from biomass in pulp and paper mills.” Environmental Engineering and Management Journal , Vol. 7, No. 5, 537 - 546. September/October 2008. P. 542.