Effect of Georgia-Pacific Palatka Process Optimizations on Effluent Quality

Prepared by L.B. Sonnenberg, Ph.D. Research Professor of Chemistry, Millar Wilson Lab at Jacksonville University

Prepared for Melissa Long, P.E. Water Facilities Administrator, Fla. Dept. of Environ. Protection

Date: June 5, 2010

Introduction

The purpose of this review is to summarize and evaluate the steps taken by Georgia-Pacific to improve

effluent quality within the manufacturing process. Emphasis is placed on the reduction of conductivity

and color. The information is compiled from the following GP reports:

a. “Production Optimization and Saltcake Alternatives” 9/1/09

b. “Additional Information Regarding Facility Optimization Report” 5/30/2008

c. “Report on Georgia-Pacific Palatka Operations Optimization of Manufacturing

Equipment Mar 2006-Mar 2007

d. Water Quality Monitoring Final Report 6/16/08

Background

Since 2000 the G-P Palatka mill has installed a reverse osmosis system for boiler feedwater (2000), a 3-

stage ClO2 bleach plant with a new ClO2 generator (2001), a new dregs liquor press (2003), new

condensate collection and treatment equipment (2005), new brownstock washers (2005) and an

oxygen delignification system (2006) to improve effluent quality. Numerous optimization steps have

been performed, including improving caustic quality and reducing usage, upgrading post oxygen washer

filtrate systems, and modifying brownstock washers, among others. In addition, black liquor spills from

overflowing charge tanks in the digester area and black liquor losses during saltcake purging have been

minimized.

In recent years, G-P Palatka has also significantly tightened its saltcake cycle. It now produces 13 t/ day

from the ClO2 generator and approximately 120 t/day from the recovery electrostatic precipitator. In

the past, ESP catch was solely used for makeup chemical, but currently, the mill uses all of the high-

purity ClO2 saltcake and approximately 108 t/day of the ESP saltcake for a total 121 t/day makeup

chemical. Approximately 11 t/day of the low-purity ESP saltcake is sewered for control of sulfur and

nonprocess elements. Chloride content dictates the exact rate of sewering.

With the current process and wastewater treatment configurations, final effluent conductivity has

declined to a reported daily maximum conductivity of 2280 umho (excluding outliers, as per H. Flippen

5/10) and color now has a daily maximum color value of 1330 pcu (Brown and Caldwell Technical

Memoranda 1-4). Both parameters still substantially exceed the Rice Creek discharge limits of 1650

umho and 275 pcu.

Alternative ESP Saltcake Disposal Options

GP believes that the Palatka mill effluent conductivity values are typical for comparable mills in the US,

but has examined opportunities to further reduce it in the final effluent by eliminating purging the

saltcake into the sewer. Options investigated included marketing excess sodium sulfate, disposing of

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saltcake in the Putnam County landfill, disposing of it on site, and by the application of a chloride

removal process (CRP).

GP concludes that the amount of sewered saltcake is now so low (11 t/day), disposing of it elsewhere

would reduce conductivity by only about 150 umhos. Rice Creek conductivity limits could still not be met

thus none of the options was cost-effective. In the following discussion, unresolved issues are addressed

that may affect the cost-benefit analysis.

The composition of the ESP catch from 2002/2003 was used in the analysis of marketing options by S.

Makris (2004) and S. Banerjee (2009 to determine whether the product met different industry

specifications (mainly detergent, glass, textiles, and pulp and paper). These samples predated all of the

brownstock washer upgrades and oxygen delignification, among many more minor modifications that

might be expected to affect purity. Limited composition data for ESP catch from 2009 was provided by

GP (GP response to L. Sonnenberg 2009) which indicates substantial change in composition, including

much higher calcium and magnesium levels than previously reported for 2002/2003 data. Typical ESP

catch composition for O2D ClO2 mills is not readily available but the values reported for an unspecified

mill (TAPPI 80(6): 154 (1997)) are quite different with substantially less calcium (90 ppm vs 28,000 ppm

for Palatka), magnesium (30 ppm vs 13,600 ppm for Palatka), and iron (70 ppm vs 142 ppm for Palatka).

To market saltcake, levels of some metals, chloride, moisture, and particle size specifications are

particularly critical. However, few of those constituents were reported in the updated ESP catch

analysis. Levels of chloride, moisture, bicarbonate were not reported, nor particle size distributions so

feasible disposal options for current ESP catch cannot be evaluated. However, a 0.7% chloride level in

the “chemical recovery system” was mentioned in “Request for Additional Information Regarding

Facility Optimization Report” (5/30/2008) in discussions of the CRP process, but no other data were

provided that corresponds to that value; a 7% as NaCl (4% as Cl) value was reported for the 2002/2003

precipitator catch analyses. It is unclear if the current catch is 0.7% Cl (1.2% as NaCl) and how that

relates to marketability because the Makris saltcake marketing report indicated that a 1.2% NaCl level

would be acceptable to P&G. Another marketing analysis including a full chemical analysis of the current

catch composition may be appropriate if the 7% reduction in conductivity is deemed significant and

useful.

The CRP process is typically used to increase chemical makeup purity so that recovery operations and

chemical usage are more efficient. By removing chloride and potassium from the low quality ESP catch

using the CRP process, the ESP saltcake could be used in the pulping process leaving the high quality

ClO2 saltcake to be marketed. Purification of the ESP catch to the point where it is marketable to pulp

mills, may also be an option, as suggested in the internal memo from J.W. Brown to Mike Curtis

6/18/09. Alternative treatments to CRP to purify ESP catch to improve its marketability were not

addressed. As with other options, CRP was judged infeasible. The low chloride content of the “chemical

recovery system” at Palatka (see above) was cited as one reason that CRP is a poor option since purging

for chloride was already minimal. While the saltcake composition used in the CRP analysis appears to be

inaccurate for the current Palatka ESP catch (e.g., 20% carbonate), the final conclusion that conductivity

is not reduced enough to warrant the cost would not be affected.

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Conductivity and Color Loading in Sewers

Daily loadings (lb/day) of conductivity and color were measured for eight sewers (“Report on Georgia-

Pacific Palatka Operations Optimization of Manufacturing Equipment Mar 2006-Mar 2007) on an

unspecified date in order to examine the impact of different manufacturing processes on wastewater.

No discussion or analysis of these results was provided. Sewers serving the 1) caustic pulp Mill, 2) Kraft

paper machine and the multiple effects evaporator, 3) acid bleach plant, and 4) ash pond wastewaters

contribute 20-10% each of the total conductivity loading. The sum of the sewer conductivity loading

represented 89% of the WWTP inlet (unspecified date). The Sump Boulevard station is the site of

saltcake sewering (GP response to L. Sonnenberg 2009), however that name is not included in the sites

listed in the conductivity audit so it is uncertain whether the saltcake sewering was included or if it

contributed to the 11% discrepancy between the sewers and treatment plant inlet.

GP also found that the most color in lb/day were from the 1) caustic pulp mill, 2) Kraft paper machine

and the multiple effects evaporator, and 3) acid bleach plant in that order (31 – 11%). The sum of the

sewer loadings was 102%. The 99th percentile for the final effluent was calculated to be 788, but that

value is more consistent with the clarifer inlet at approximately 600 pcu with reversion raising the color

to an average 1000 in the final effluent (Brown and Caldwell Technical Memoranda 1-4).

One or more sewer streams may be more efficiently treated for high levels of salt or color than

treatment of biologically treated effluent. This may be particularly true for high color streams where

early removal prevents reversion, which ultimately reduces the overall extent of the problem. To fully

assess the feasibility of selective stream treatment, current information is needed about flow rates of

individual sewers, ion composition, solids, and concentrations of other constituents.

Water Quality Results 2007-2008

Effluent quality has improved, but water quality monitoring in Rice Creek for one year after process

modifications indicates that the mill’s discharge canal at mile 3.4 does not meet conductivity and color

water quality standards of 1275 umho and 275 pcu. The discharge canal ranged in conductivity from

1820 to 3134 with an annual average of 2376 (approximately 25% higher than currently reported levels

of 1900 umhos). Color averaged about 995 pcu, which is similar to what is currently reported (1000 pcu).

A background site, Rice Creek at Bardin Road, ranged in conductivity from 82-439 umho (236 average).

The color in upstream Rice Creek ranged from 15-1300 pcu with an annual average of 277, which just

barely meets the water quality standard of 275 pcu (36% exceedences of WQS). There is likely to be

much less tidal influence at the Rice Creek upstream site compared to the mill discharge points so

significant natural differences in these parameters might be expected between those sites.

A second background site in Etonia Creek ranged in conductivity from 80-1105 umho (166 average). The

color ranged from 15-1300 pcu with an annual average of 232 and a WQS exceedence rate of 29%. In

addition to the discharge of wastewater into Rice Creek, differences in water quality between Rice Creek

and Etonia may be due to different tidal influences and the water consumption by G-P that occurs at

Etonia.

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Rice Creek sample sites that benefit from dilution from tributaries and wetlands were not sampled so

the status of the creek with respect to water quality standards is not completely addressed. The

reference sites may also be sufficiently different from the tidally-influenced Rice Creek so that other

reference sites might be more appropriate.

Summary

Extensive process changes in the mill have not produced effluent with a high enough quality to meet

FDEP standards particularly for conductivity and color. Removal of purge saltcake from the waste stream

will result in an approximate 7% reduction in conductivity with the current saltcake cycle, insufficient to

meet standards. Conductivity sources other than sewered precipitator catch were not extensively

investigated, nor were options for the minimization of different sources addressed. Because monitoring

was restricted to the discharge canal, which does not meet WQS for conductivity and color, compliance

for the rest of Rice Creek is not addressed in the monitoring report.