CICEET Progress Report for the period 3/15/05 Through 9/15/05

Project Title: In Situ Sediment Ozonator for Remediation of PCB, PAH, DDT and Other Recalcitrant Chemicals
Principal Investigator(s): Andy Hong
Additional Investigator(s): Don Hayes
Project Start Date: 1 September 2004

Figures

Figure 1

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Figure 9

Tables

Table 1

Table 2

Table 3

Table 4

Table 5

Table 6

Table 7

Table 8

Table 9

Table 10

Table 11

• Are the intermediates and products of PCB, DDT and PAH after ozonation amenable to biodegradation?
• Are nutrient supplements helpful for subsequent natural bioremediation?

On the In Situ Sediment Ozonator (ISO) Equipment
To provide answers to the following questions concerning operation of the equipment:

• What minimum range of relative centrifugal force will be necessary to dewater sediments following treatment with ozonation?
• What are other means by which treated sediments can be dewatered?
• What admixtures can be added to sediments to provide physical and chemical stability when re-deposited?

Tasks to meet objectives
On The Chemical-Biological Process

• Biodegradability tests for the intermediates and products
• Biodegradability tests with nutrient supplements for the intermediates and products

On the In Situ Sediment Ozonator (ISO) Equipment

• Additional sediment was gathered for use in centrifugation tests.
• Initial centrifugation tests were conducted to identify a useful range of relative centrifugal force that can be used in concentrating sediments.
• A survey of existing dewatering technologies was performed to identify technologies that are applicable to this device.
• A detailed experimental plan was developed for testing the effect of admixtures on sediment physical and chemical stability.

Progress on Tasks
On The Chemical-Biological Process

• Completed degradation studies of Aroclor 1242 spiked sediment in aqueous phase by ozone, with ultrasound irradiation and biological incubation.
• Completed degradation of DDT spiked sediment and its intermediates in aqueous phase by ozone and biological incubation.
• Working on integrated chemical and biological treatment for Waukegan Harbor (PCBs and PAHs), Passaic River (PAHs), and St. Louis River (PAHs) sediments.

On the In Situ Sediment Ozonator (ISO) Equipment

• Additional sediment was collected from wetlands near the Great Salt Lake. These clayey soils were useful for centrifugation tests and will be used in future tests of dewatering technologies.
• A minimum range of relative centrifugal force of 2000-3000 rpm recommended for dewatering of sediments.
• Filter screens, centrifuges, hydrocyclones and belt presses were identified as possible dewatering technologies. Of these, filter screens appear to be the most applicable to this device. In particular, self cleaning filter screens that can eject dewatered sediments quickly through an auger and plunger mechanism, without addition of significant wash water are the most promising. Two manufacturers of filter screens have been contacted for detailed technical specifications. The lower particle size limit for all of the surveyed technologies is between 5 and 10 microns.
• An experimental plan to test various admixtures for their effect on sediment stability has been developed.

Difficulties
On The Chemical-Biological Process
The sediment samples were heterogeneous in nature and variations among samples can be significant. This difficulty is overcome by slight modifications of EPA’s analytical protocol and cleanup procedures, with substantial amounts of replicates. The samples from real sediments have significant organic matters which reduce the efficiencies of ozonation even after the application of ultrasound irradiation and use of acetic acid as a solvent. On the other hand, PAHs (initially at 40.2 mg/Kg) in the Passaic River sediment were reduced by 60% within 30 min of ozonation despite very high organic contents (14.4%) (detailed results are being collected and will be available in the next report).

Project Objectives for Next Reporting Period

Objectives
On the Chemical-Biological Process
To provide answers for the follow-up question: What are the important process parameters and treatment efficiency accordingly?

On the In Situ Sediment Ozonator (ISO) Equipment
Begin testing of various admixtures for effects on sediment physical stability.

Tasks to Meet Objectives
On the Chemical-Biological Process
Characterize treatment efficiencies according to varying treatment parameters

On the In Situ Sediment Ozonator (ISO) Equipment
Construct testing device for comparing the sediment’s ability to resist erosion. Either a SED Flume or Shaker device will be built once feasibility of construction is determined.

Work Plan for Next Reporting Period
On the Chemical-Biological Process
The development is on track. We will continue development as proposed to:

• characterize biotreatment with varying amounts of added carbon and oxygen source
• characterize treatment performance by varying treatment parameters such as contact time, ozone concentration, solid concentration, and mixing intensity, etc.

On the In Situ Sediment Ozonator (ISO) Equipment
Conduct series of tests to determine optimum characteristics and composition of "engineered sediments". Ideal properties will include resistance to erosion and ability to sequester residual contaminants.

Anticipated Success in Meeting Project Objectives
On the Chemical-Biological Process
We expect to successfully carry out the planned tasks for the next 6 months, in which we expect to add insights to how various process parameters and ranges that will contribute to more effective treatment.

On the In Situ Sediment Ozonator (ISO) Equipment
The above tasks and work plan will determine optimum admixtures and overall characteristics of the sediment that is replaced by the ISO following ozonation.

Overall Project Timeline Update
On the Chemical-Biological Process
Our development is on track as originally proposed, and we don’t find any changes to original schedule necessary.

Preliminary Data
Degradation of DDT using ozone in CCl₄ solution
Results and Key Conclusions

• Table 1 shows the intermediates and byproducts identified after the ozonation of DDT in Carbon Tetrachloride as identified by GC/MS.
• Figure 1 shows the profiles of the concentrations of intermediates and byproducts detected by GC/MS vs. Time (min).

Key Conclusion
From intermediates and products identified by GC/MS, it seems apparent that free radical reactions are involved, in addition to direct electrophilic attacks by ozone on the benzene rings. With increased ozonation time, DDT and the concomitant intermediates and byproducts degrade completely.

Degradation of DDT using ozone in aqueous phase
Procedures:
DDT was coated onto glass beads by immersing the glass bead into a DDT/acetone solution and subsequent solvent evaporation. The DDT-coated glass beads were packed in a glass column, which received ozone-laden water flowing through the packed bed in an upflow mode. Contents of the effluent were analyzed by toxicity test, COD, BOD5, BOD10, BOD15, BOD20, and qualitative and quantitative analysis of DDT by GC/ECD or GC/MS. The effluents were further biologically incubated for 5-12 days and were extracted and analyzed again.

Results and Conclusions/Comments

• Table 2: Results of DDT degradation using ozone in the aqueous phase in a packed column reactor at various reaction times.
  Conclusions: DDT was partially degraded using ozone in aqueous phase in a Packed Column Reactor, but the percentage degradation varied with different reaction times and DDT loading.
  
  
• Table 3: COD values for effluents obtained from the reaction of DDT with ozone in the aqueous phase passing through the packed column reactor.
  
  
• Figure 2: COD profiles of effluents obtained from reaction of DDT with Ozone in aqueous phase passing through the packed column reactor against the COD of acidic water without ozone passing through the DDT loaded reactor.
  Conclusions: The CODs of the effluents obtained after ozonation of DDT were higher than the COD of effluents obtained by passing acidified water without ozone. The results indicate that ozone in the aqueous phase broke down DDT to intermediates and products, resulting in higher COD values.
  
  
• Table 4: BOD values for effluents obtained from the reaction of DDT with ozone in the aqueous phase passing through the packed column reactor.
  Conclusions: BOD tests for 5, 10, 15, and 20 days were performed on the effluent samples obtained at different time intervals of the reaction. BOD values for 5 and 10 days were very low and for 15 and 20 days were similar to the the 10-day BOD value. The low BOD values and the extremely low ratio of BOD/COD indicated that the effluent obtained after ozonation was not amenable to biological treatment.
  
  
• Table 5: Results obtained for Biological Incubation.
  Conclusions: The results obtained from the incubation of effluents with enriched microorganisms drew a different conclusion altogether. There was no DDT observed after 12 days of incubation with the enriched microorganisms from the Waukegan Harbor sediment. The original microorganisms that were observed to have pale yellow color with foul smell, turned pink with a fresh smell after 10 days of incubation. The pink microorganisms consumed DDT and predominated in the system with increasing incubation time (Further characterizations are being planned on the microorganisms).

Degradation of DDT spiked sediment using ozone in aqueous phase
Procedures:
A sediment from South Utah Lake was prepared and spiked with DDT using acetone as a solvent. The spiked sediment was ozonated in a glass batch reactor. The treated sediment was then vacuum filtered, extracted, removed of sulfur before analysis using GC/ECD.

Results and Conclusions/Comments

• Figure 3: Ozonation and Aeration of DDT Spiked Sediment, Percentage Remaining vs. Time (min). DDT concentrations after various reaction times were compared to those after 2 hours of aeration without ozonation.
  Conclusions: Ozone reduced DDT in sediments given enough reaction time. Ozonation may provide a feasible technique to treat DDT contaminated sediment.

Ozonation of PCBs in Aroclor 1242 spiked sediment
Procedures:
A sediment obtained from South Utah Lake was spiked with PCBs (Aroclor 1242), and the spiked sediment in slurry form (20 g/100 mL) was ozonated for different times. The treated sediment was filtered, extracted, cleaned of sulfur, and analyzed by GC/MS/

Results and Conclusions

• Figure 4: Degradation of PCB in spiked South Utah Lake sediment under different conditions.
  Conclusion: PCBs in spiked sediments were lowered with ozonation and even with aeration. Maintenance of neutral pH did not improve treatment.
  
  
• Figure 5: Degradation of PCBs at different pH values after 60 minutes ozonation. (0.1M NaOH solution was added to maintain pH > 7; acetic acid and sulfuric acid (triangle point) were added to maintain pH < 5.)
  Conclusion: Degradation of PCB was enhanced by the addition of acetic acid (This was not caused by pH drop, as addition of inorganic acid did not increase the degradation of PCB).
  
  
• Table 6: Degradation of PCBs in spiked sediment after 30 minutes ozonation with different acids concentrations (ultrasound irradiation was applied).
  Conclusion: The use of 10% acetic acid along with ultrasound irradiation completely degraded PCBs within 30 minutes.
  
  
• Table 7: The degradation of PCBs in spiked sediment with various intervals of ultrasound irradiation applied in the reaction system.
  Conclusion: Ultrasound irradiation itself may promote free radical reactions in the aqueous phase. It may have played a role in the enhanced degradation of PCBs in the aqueous phase.
  
  
• Table 8: The degradation of PCBs in the spiked sediments with various amounts of added acetic acid.
  Conclusion: Acetic acid plays an interesting role in the degradation of PCBs. These may be the relevant factors: increased ozone solubility, increased contaminant dissolution and exposure to ozone, as well as surface tension change throughout the solid-liquid interface. The roles of acetic acid in chemical process along with its potential as a carbon source in subsequent biological treatment are being examined.
  
  
• Table 9: The results of incubation with microorganisms
  Conclusion: PCBs and products in spiked sediment after ozonation were removed by microorganisms. The integrated chemical and biological treatment of PCBs warrants further investigation.

Degradation of PAH in St. Louis River Sediment using integrated chemical-biological treatment.
Procedures:
A St. Louis River sediment sample largely contaminated by PAHs was ozonated in slurry form (20% w/w) to examine treatment feasibility based on ozonation, ozonation followed by biological incubation, as well as the use of an oxygen release compound (ORC). All treated samples were extracted and analyzed by GC/FID techniques.

Results and Conclusions

• Figure 6: Degradation of PAH using only Ozonation
  Conclusion: From Graph-1, PAH degradation increases with increased ozonation time. After around one hour the curve starts flattening out, and after two hours around 67% of PAH is degraded. One hour of ozonation time appears to be good enough to obtain close to maximum degradation. The degradation due to aeration is mainly because of evaporation of highly volatile PAHs
  
  
• Figure 7: Effect of Ozone Release compounds on degradation of PAH.
  Conclusion: The intermediates obtained from ozonation are readily oxidizable and the oxygen release compounds (ORC) enhances the degradation of these intermediates. After five weeks of incubation with ORCs, 80% degradation can be obtained for the 30-minutes ozonated sample.
  
  
• Table 10: Amount of PAH after degradation with ORC
  Conclusion: Tables 10 shows that PAH is getting reduced as the incubation time is increased. The maximum degradation is achieved in the first three weeks. Although PAH is degraded in last two weeks, it is insignificant compared to degradation obtained in first three weeks.
  
  
• Figure 8: Integrated Chemical-Biological degradation of PAH.
  
  
• Table 11: Amount of PAH after of incubation with added microorganisms
  Conclusion: 15 minutes of ozonation followed by 20 days of biodegradation results in 92% degradation of PAH. Addition of ORC to the biological reaction certainly helps but the effect of ORC is minimal.
  
  
• Figure 9: Comparison of different techniques used to degrade PAH in St. Louis River Sediment
  Conclusion: If the process is designed to degrade PAH, the sediment sample should be ozonated for 15 minutes and followed by incubation with the microorganism over the course of 20-30 days. Some ORC compounds can also be added to achieve higher degradation but the effect of ORC compounds is minimal.

Dissemination
Publications:
H. Xu; A. Hong; D. Hayes. "Reaction Kinetics and Products of Aroclor 1242 Congeners with Ozone." ICER, in revision.

S. Nakra; A. Hong; D. Hayes "Chemical and biological treatment of PAH contaminants in St. Louis River Sediment." In preparation

H. Xu; T. Datta; A. Hong; D. Hayes "Kinetics and Mechanism of Degradation of DDT in Organic Solvent and in Aqueous Environment." In review.

H. Xu; A. Hong; D. Hayes. "Reaction Kinetics and Products of Aroclor 1260 Congeners with Ozone." In preparation.

H. Xu; Z. Cha, A. Hong; D. Haye "The Degradation of PCBs in Aroclor 1242 Spiked Sediment by Integrated Ozonation, Ultrasound Irradiation and Biological Degradation." In preparation

Workshops:
None.

Conferences (6-7 participants including the PIs and students on the project):
B. Starr; D. Hayes, A. Hong "Development and Design of an In Situ Sediment Ozonator for Contaminants Remediation," the 16th Annual AEHS Meeting & West Coast Conference on Soils, Sediments, and Water, March 13-16, 2006, San Diego, CA.

B. Starr; D. Hayes, A. Hong "Development and Design of an In Situ Sediment Ozonator for Contaminants Remediation," the 16th Annual AEHS Meeting & West Coast Conference on Soils, Sediments, and Water, March 13-16, 2006, San Diego, CA.

Z. Cha; H. Xu; A. Hong; D. Hayes "Degradation by Ozonation of PCBs in Spiked and Waukegan Harbor Sediments," The 16th Annual AEHS Meeting & West Coast Conference on Soils, Sediments, and Water, March 13-16, 2006, San Diego, CA.

H. Xu; A. Hong; D. Hayes "Chemical-Biological Treatment of PCBs in Contaminated Sediments," The 16th Annual AEHS Meeting & West Coast Conference on Soils, Sediments, and Water, March 13-16, 2006, San Diego, CA.

A. Hong; H. Xu; D. Hayes "Reaction Kinetics and Products of Arochlor Congeners with Ozone," The 16th Annual AEHS Meeting & West Coast Conference on Soils, Sediments, and Water, March 13-16, 2006, San Diego, CA.

T. Datta; H. Xu; A. Hong; D. Hayes "Chemical Treatment of DDT in Organic and Aqueous Phases and Biological Incubation," the 16th Annual AEHS Meeting & West Coast Conference on Soils, Sediments, and Water, March 13-16, 2006, San Diego, CA.

S. Nakra; A. Hong; D. Hayes "Degradation of PAH contaminants in St. Louis River Sediment with Chemical-Biological Treatment," The 16th Annual AEHS Meeting & West Coast Conference on Soils, Sediments, and Water, March 13-16, 2006, San Diego, CA.

A. Hong, H. Xu, D. Hayes "In Situ Chemical-Biological Treatment of PCB-Contaminated Sediment," 15th Annual AEHS Meeting and West Coast Conference on Soils, Sediments, and Water, March 14-17, 2005, San Diego, CA.

D. Hayes and A. Hong "Innovative concept for in situ contaminated sediment remediation," Western Dredging Association (WEDA) 2004 conference, July, Orlando, Florida.

Manuals, Protocols: None

Outreach Activities: None

Contact with End Users:
This report will be reviewed by Dr. Kerstin Wasson, Research Coordinator for Elkhorn Slough NERR, CA.

Patent, Copyright, Invention Disclosure Activity:
Hong, Hayes, In Situ Sediment Ozonator for Contaminants Remediation. U#3287. Prov. Appl. 12/2004.

Expenditures
Our expenditures are in the range of anticipated, and as proposed.