D164-9 6-10-2010 Review of Legacy Solids

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Review of Legacy Solids in Georgia-Pacific Wastewater Treatment Ponds

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

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

Date: June 10, 2010

Background

The presence of dioxin in Rice Creek fish from 2003-2007 indicated that additional study of potential

sources was needed. A novel High Volume Extraction study of polychlorinated dibenzodioxin and

dibenzofurans (PCDD/F) in the water column of Georgia-Pacific Palatka wastewater treatment ponds at

the Pond 4 discharge site was conducted by USEPA in 2008. The study produced positive results that

instigated a follow-up study to examine polychlorinated PCDD/Fs in sludge in the four treatment ponds.

A summary of the results from Georgia-Pacific Palatka Wastewater Treatment Plant Legacy Solids

Study(September 1, 2009) is provided below, along with additional data analysis and

recommendations for continued investigation. References to Georgia Pacific High Volume SamplingStudy Report, USEPA Region 4 February 2009are included.

Study Scope and Methods

Fourteen sites were sampled in the four wastewater treatment ponds. Because of the high amount of

solids in Pond 1 and its large size, seven sites were sampled there, and two samples were taken in each

of Ponds 2-4 and from the emergency spill basin. Clarifier solids were also analyzed. At each site in Pond

1 an interface sample (clamshell) and a core was collected. Generally, the core samples had much higher

solids content than the grab samples, typical of the different collection techniques. The other 3 ponds

were sampled at the interface. Reports by G-P Palatka personnel indicate that Ponds 2-4 have a hard

pan that is blanketed by only a small layer of collectable solids which were highly organic in nature (DEP

meeting Dec, 2009).

As per EPA Method 1613, samples with greater than 1% solids were analyzed as solids (Soxhlet

extraction of solids after decanting or filtering excess water), and samples with less than 1% solids were

analyzed as aqueous samples. Hereafter, samples with less than 1% solids are referred to as aqueous

samples, and those with greater than 1% solids as solid samples. Solids contents were determined in

aqueous samples by filtration (GF/D filter with 2.7 um particle retention) and in samples with greater

than 1% solids by drying. These details were not provided in the report but are designated in the EPA

Method 1613.

To calculate the concentration of 2,3,7,8-TCDD in solids in the aqueous samples, it was assumed by the

authors of the Legacy Solids report that all PCDD/F was associated with the filter-retained solids (greater

than 2.7 um particle size). All values were reported in ng PCDD-F/kg dry weight solids in Table 1. It

should be noted that if a significant fraction of solids was less than 2.7 um in size (and were therefore

excluded in the percent solids measurement), then this technique could overestimate the

concentrations in the aqueous sample solids. Full congener analyses were performed and data were

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Legacy Solids in G-P Wastewater Ponds 06/10/10 Sonnenberg MWL-JU

provided in the appendices, but only 2,3,7,8-TCDD was discussed in the report. The depth of the solids

layers were also measured at each site, though data were not provided.

Potential mechanisms for discharge of TCDD-laden solids were evaluated including partitioning to the

water column, hydraulic scouring, biological mixing, and wind mixing. The latter was considered the

most likely, though biological mixing was acknowledged as possible. Discussion of remediation options

focused on removal of suspended solids and minimization of resuspension due to wind as part of an

overall wastewater treatment plant improvement. The potential for harmful discharge of PCDD/Fs was

deemed insignificant and unimportant based on 2004 fish studies and the nonstandard nature of the

HVE methods.

Results

The 2,3,7,8-TCDD concentrations in solids in core samples averaged 65 ng/kg, with a median of 4 ng/kg,

The average concentration in solids in interface samples was 42 ng/kg and the median was 16. These

summary values were calculated from data in Table 1 in the Legacy Solids report, but review by the

MWL revealed a discrepancy in one of the Pond 4 samples (sample number 4), which raises these

average numbers slightly. It should be noted that these summary statistics, as well as those reported

below, treat nondetects as zero.

The values of the core samples were not significantly different from those of the interface samples. No

PCDD/Fs were detected in the primary clarifier solids while the emergency spill basin sample had the

highest aqueous concentrations (pg/L), and had the most congeners detected. The cleanliness of the

primary clarifier solids suggests that PCDD/Fs are not in the primary solids coming from the mill.

The report did not include discussions about the remaining congeners, which consisted primarily of

2,3,7,8-TCDF (excluding pervasive octachlorinated compounds), which were usually present in

concentrations higher than TCDD. Toxicity equivalency calculations using WHO TEFs, yielded a TEQ

average concentration of 76 ng TEQ/kg (median 15 ng/kg), excluding the primary clarifier. The high

variability between samples was demonstrated by the 190% coefficient of variation. For perspective,

EPA reports a 5.3 ng TEQ/kg background concentration in sediment for the US (EPA 2003). On average,

the 2,3,7,8-TCDD congener was responsible for 61% of the TEQ (76% median). In the HVE study, 68% of

the total TEQ was due to 2,3,7,8-TCDD. Exclusive focus on 2,3,7,8-TCDD may underrepresent the actual

potential toxicity of the PCDD/F mixtures.

Comparisons to HVE data

The average concentrations of 2,3,7,8-TCDD and TCDF in aqueous samples in the Legacy Solids study,

were 51 and 212 pg/L, respectively (Legacy Solids, Appendix 4). Without the ESB, the averages were 41

and 122 pg/L for TCDD and TCDF. By comparison, in the HVE study, the average of the duplicate samples

for total TCDD was 0.06 pg/L and TCDF was 0.14 pg/L (including both particulate and aqueous phases).

The average solids concentrations of 2,3,7,8-TCDD and TCDF in the Legacy Solids study were 97 and 225

ng/kg respectively (Legacy Solids, Appendix 3). In the HVE study, average calculated solids phase


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concentrations of 2,3,7,8-TCDD and TCDF were 6 and 11 ng/kg, respectively. The latter calculations

were based on an average 8.1 mg/L suspended solids determined from values reported in the HVE

study.

The samples collected near the bottom of the ponds appear to have significantly higher PCDD/F

concentrations than the samples that were collected at the surface at the pond 4 outfall. The

differences may have arisen because pore water is isolated from the bulk water, because the HVE

method undermeasures PCDD/Fs, or because of discrepancies in the operational definitions of solids. It

is also unknown whether suspended solids have lower concentrations than bulk solids due to different

particle characteristics (e.g., size, lipids, TOC) or because of isolation of the sludge bottom from the

overlying water column. Understanding the sources, fates, treatability, and potential impacts of the

PCDD/Fs in the ponds depends on these answers.

The HVE study data suggest that at a 23 MGD discharge rate, approximately 101 ug/day of total PCDD/F

is discharged, corresponding to 8 ug total TEQ/day.

PCDD/F Phases

In the Legacy Solids report, it is assumed that all PCDD/Fs are associated with particles, with no

discussion of particle sizes. While a large percentage of the PCDD/Fs are expected to be adsorbed to

particulates (depending on the particle characteristics and the specific congener), some may be

dissolved or associated with very small particles or colloids. The HVE study differentiates the particulate

and dissolved phases with a 1 um particle size cutoff for the particulate phase. The table below

indicates that a significant fraction of PCDD/Fs are either dissolved or associated with particles less than

1 um in size. In addition, the aqueous sample 12B from Pond 1 had detectable amounts of PCDD/Fs

although the solids content is reported as zero, suggesting the presence of dissolved phase compounds

or sorption to particles smaller than 2.7 um. Finally, Amendola et al. (TAPPI 1989) found that final pulp

and paper mill effluents (activated sludge treatment) have 40-75% of TCDD/F in particulate phase,

consistent with the results shown below. These results raise the question of the exact efficiency of TSS

removal in reducing PCDD/Fs, particularly without knowing their particle size distributions.

Table 1. Distribution of PCDD/Fs in Aqueous and Particulate Phases (EPA HVE Study)

Congener Percent in particulate phase

2,3,7,8-TCDD 74%

2,3,7,8-TCDF 63%

1,2,3,7,8-PCDD 100%

1,2,3,7,8,9-HCDD 100%1,2,3,4,6,7,8-HpCDD 86%

1,2,3,4,6,7,8-HpCDF 100%

OCDD 91%

OCDF 50%

Total/Average 75%


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Sludge and PCDD/F Mass Balance and Distribution

From depth measurements, G-P estimated the mass of sludge in each pond. Average TCDD

concentrations in each pond were used to determine its mass loading. These balances should be

considered very rough estimates because the sampling grid was very large (significant accumulation at

quiescent edges or scouring near outflows could significantly change the solids depths), and because of

the large variability in the sample concentrations. The compression or density of the sludge bottom is

also an important variable.

The mass of TCDD is greatest in Pond 1, which contains approximately 93% of the estimated total 2.5 g

TCDD in all of the ponds. It is where most of the BOD removal takes place and therefore contains much

more solids than the other ponds. The average concentrations of TCDD in Ponds 1,2,3, and 4 were 41,

12, 176, and 5 ng/kg, respectively. There was a single very high outlier in Pond 3 (474 ng/kg); without

that outlier, the average of Pond 3 is 28 ng/kg. There is no clear trend in concentrations over the

different ponds. When the full congener distribution is considered, the mass in the entire wastewater

treatment system is estimated to be 3.7 g TEQ with 92% in Pond 1.

Plan for Remediation

G-Psdiscussion about remediation focused largely on the facts that there were nondetectable levels in

some samples, the HVE study does not follow EPA Method 1613 procedures, fish consumption

advisories for Rice Creek were not issued for dioxins in a 2004 US Department of Health report, G-P has

invested significant resources in BAT upgrades, and that reducing the already-low TSS levels would be

examined in a forthcoming engineering feasibility study.

The analysis method 1613 was adopted by EPA well over a decade ago and in comment periods, the

agency recognized that it will continue to explore new measurement techniques to develop methods

that yield MDLs that will allow determination of 2,3,7,8-TCDD at the ambient criteria level (CFR 1997).

The HVE study, performed by EPA, followed typical EPA QA/QC procedures which supported the validity

of the results. If the HVE method is inaccurate, it is likely that it reports erroneously low values due to

inefficient XAD-2 extraction. For those reasons the HVE results should not be dismissed.

While there is no fish consumption advisory in Rice Creek, it is listed as an impaired water body in the

DEP 2009 303(d) verified lists. Furthermore, comments in the verified list state that Rice Creek is

impaired for one or more designated uses but does not require TMDL development because the water

will attain water quality standards due to existing or proposed measures. Additional notes state:

Georgia Pacific has instituted control measures that provide reasonable assurance the dioxin will not be

present in its effluent. At this time, there appears to be no data that indicates whether or not Rice

Creek meets the 0.014 pg/L ambient water quality criterion. As a consequence, it is important that G-P

definitively demonstrate that dioxins are not present in its effluent, regardless of whether a fish

consumption advisory has been issued.

Reduction of TSS may not directly correlate to reduction in PCDD/Fs, depending on the particle size

distributions of the compounds and the particle sizes that are removed. As discussed earlier, more data


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on their sources and distributions, along with direct demonstration of their removal with any proposed

technology would be necessary to definitively determine the potential for their discharge.

Sources

Historic production and subsequent retention of the recalcitrant PCDD/Fs is assumed to be the cause for

their presence in the four treatment ponds. The prevalence and ratio of 2,3,7,8-TCDF and 2,3,7,8-TCDD

is consistent with historic bleaching practices (McDonough 1993). However, it is puzzling that the ESB

would be so contaminated because it was dredged in 2006 (G-P response to L. Sonnenberg 2009). The

sludge pond would also seem to be a likely reservoir for the compounds, and it may be feeding colloidal

PCDD/Fs back into the clarifier from the supernatant. Investigation into other areas on the G-P premises

where dioxins could be present may allow more remediation options.

While the focus of these studies is on PCDD/Fs, it should be recognized that old manufacturing

processes in the pulp and paper industry produced many more toxic compounds (e.g., PCBs,

chlorophenols, and mercury), some of which have been found in high levels in sediments of Rice Creek

(LSJR River Report 2009). If the source of the PCDD/Fs is historic, then their presence in the sludge and

effluent may indicate the presence of other recalcitrant and potentially harmful compounds.

Summary

The Legacy Solids study verified that PCDD/Fs are present in G-P wastewater ponds. The sludge contains

PCDD/Fs at levels well above background sediment levels. The cleanliness of the primary clarifier solids

suggests that PCDD/Fs are not in the primary solids coming from the mill, but their presence throughout

the G-P Palatka complex is incompletely understood. The distribution of PCDD/Fs in different phases of

the wastewater treatment system is also not clear. The fates, treatability, and potential impacts of the

PCDD/Fs in the ponds will depend on how they are distributed in aqueous phase and in settled and

suspended solids. Exclusive focus on 2,3,7,8-TCDD may underrepresent the actual magnitude of the

PCDD/F contamination. If the source of the PCDD/Fs is historic, then their presence in the sludge and

effluent may indicate the presence of other historic recalcitrant and potentially harmful compounds.

References

Amendola, G.A., R.E. Handy Jr., D.G. Bodien, Bench-scale study of dioxins and furan (2,3,7,8-TCDD and

2,3,7,8-TCDF) treatability in pulp and paper mill wastewaters TAPPI Journal, December 1989, p. 189.

40 CFR Part 136 Guidelines Establishing Test Procedures for the Analysis of Pollutants; EPA Method

1613; Final Rule 1997.

McDonough, T.J., Dioxins and the Paper Industry Institute of Paper Science and Technology,Technical

Paper Series No. 500, 1993, 22 p.

Jacksonville University and University of North Florida, State of the River Report for the Lower St. Johns

River Basin, Chapter 5. Contaminants. Report to the City of Jacksonville Environmental Protection

Board, 2009, 195pp.


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US Department of Health and Human Services, ATSDR, Fish in Rice Creek at the Georgia-Pacific Site

Palatka, Putnam County Fl, October 2004.

US Environmental Protection Agency (2003) Exposure and Human Health Reassessment of 2,3,7,8-

Tetrachlorodibenzo-p-Dioxin (TCDD) and Related Compounds National Academy of Sciences (NAS)

Review Draft. Volume 2, Chapter 3.

D164-9 6-10-2010 Review of Legacy Solids

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