Projection of landfill stabilization period by time series analysis of leachate quality and transformation trends of VOCs.

The purpose of this study was to evaluate suitability of using the time series analysis for selected leachate quantity and quality parameters to forecast the duration of post closure period of a closed landfill. Selected leachate quality parameters (i.e., sodium, chloride, iron, bicarbonate, total dissolved solids (TDS), and ammonium as N) and volatile organic compounds (VOCs) (i.e., vinyl chloride, 1,4-dichlorobenzene, chlorobenzene, benzene, toluene, ethyl benzene, xylenes, total BTEX) were analyzed by the time series multiplicative decomposition model to estimate the projected levels of the parameters. These parameters were selected based on their detection levels and consistency of detection in leachate samples. In addition, VOCs detected in leachate and their chemical transformations were considered in view of the decomposition stage of the landfill. Projected leachate quality trends were analyzed and compared with the maximum contaminant level (MCL) for the respective parameters. Conditions that lead to specific trends (i.e., increasing, decreasing, or steady) and interactions of leachate quality parameters were evaluated. Decreasing trends were projected for leachate quantity, concentrations of sodium, chloride, TDS, ammonia as N, vinyl chloride, 1,4-dichlorobenzene, benzene, toluene, ethyl benzene, xylenes, and total BTEX. Increasing trends were projected for concentrations of iron, bicarbonate, and chlorobenzene. Anaerobic conditions in landfill provide favorable conditions for corrosion of iron resulting in higher concentrations over time. Bicarbonate formation as a byproduct of bacterial respiration during waste decomposition and the lime rock cap system of the landfill contribute to the increasing levels of bicarbonate in leachate. Chlorobenzene is produced during anaerobic biodegradation of 1,4-dichlorobenzene, hence, the increasing trend of chlorobenzene may be due to the declining trend of 1,4-dichlorobenzene. The time series multiplicative decomposition model in general provides an adequate forecast for future planning purposes for the parameters monitored in leachate. The model projections for 1,4-dichlorobenzene were relatively less accurate in comparison to the projections for vinyl chloride and chlorobenzene. Based on the trends observed, future monitoring needs for the selected leachate parameters were identified.

[1]  J C Scully,et al.  Fundamentals of corrosion , 1990 .

[2]  R. Jones,et al.  LANDFILLS AND GROUND‐WATER QUALITY , 1991 .

[3]  B. Klinck,et al.  Human health risk in relation to landfill leachate quality , 2004 .

[4]  Frederick George Pohland,et al.  Critical review and summary of leachate and gas production from landfills , 1982 .

[5]  J. Gossett,et al.  Reductive Dechlorination of Tetrachloroethene to Ethene by a Two-Component Enzyme Pathway , 1998, Applied and Environmental Microbiology.

[6]  T. Burt,et al.  Decomposition of river water nitrate time-series — comparing agricultural and urban signals , 1998 .

[7]  E. Reardon,et al.  Anaerobic corrosion of granular iron: measurement and interpretation of hydrogen evolution rates. , 1995, Environmental science & technology.

[8]  J. McCray,et al.  Temporal changes in leachate chemistry of a municipal solid waste landfill cell in Florida, USA , 2004 .

[9]  Caroline J. Grosh,et al.  Analysis of Florida MSW Landfill Leachate Quality July 1998 , 1998 .

[10]  G. Heron,et al.  Biogeochemistry of landfill leachate plumes , 2001 .

[11]  A. Ledin,et al.  Present and Long-Term Composition of MSW Landfill Leachate: A Review , 2002 .

[12]  I. Watson-Craik,et al.  Ammonia and nitrogen fluxes in landfill sites: applicability to sustainable landfilling , 1998 .

[13]  Thomas Højlund Christensen,et al.  Landfill Emissions and Environmental Impact: An Introduction , 1995 .

[14]  M. Wong,et al.  Variations in the chemical properties of landfill leachate , 1994 .

[15]  T. Vogel,et al.  Abiotic and biotic transformations of 1,1,1-trichloroethane under methanogenic conditions , 1987 .

[16]  P. Cambier,et al.  Influence of Reducing Conditions on Solubility of Trace Metals in Contaminated Soils , 2000 .

[17]  A. M. Mårtensson,et al.  Effect of humic substances on the mobility of toxic metals in a mature landfill , 1999 .

[18]  M. Barlaz,et al.  The fate of toluene, acetone and 1,2-dichloroethane in a laboratory-scale simulated landfill , 2000 .

[19]  K. Ramanand,et al.  Reductive dehalogenation of chlorinated benzenes and toluenes under methanogenic conditions , 1993, Applied and environmental microbiology.

[20]  Fred Collopy,et al.  Decomposition by Causal Forces: A Procedure for Forecasting Complex Time Series , 2005 .

[21]  J. Gossett,et al.  Isolation of a bacterium that reductively dechlorinates tetrachloroethene to ethene. , 1997, Science.

[22]  G. Schraa,et al.  Enrichment and properties of a 1,2,4-trichlorobenzene-dechlorinating methanogenic microbial consortium , 1997, Applied and environmental microbiology.

[23]  M. D. Lagrega,et al.  Hazardous Waste Management , 1994 .

[24]  P. Nilsson,et al.  Seasonal Changes of Leachate Production and Quality from Test Cells , 1997 .

[25]  Stephen J. Lawrence,et al.  Description, Properties, and Degradation of Selected Volatile Organic Compounds Detected in Ground Water--A Review of Selected Literature , 2006 .

[26]  Wolfgang Calmano,et al.  Binding and Mobilization of Heavy Metals in Contaminated Sediments Affected by pH and Redox Potential , 1993 .

[27]  I. Cozzarelli,et al.  The Norman Landfill environmental research site: What happens to the waste in landfills? , 2003 .

[28]  John H. Gibbons,et al.  Facing America's Trash: What Next for Municipal Solid Waste? , 1992 .

[29]  T. Vogel,et al.  RATE OF ABIOTIC FORMATION OF 1,1-DICHLOROETHYLENE FROM 1,1,1-TRICHLOROETHANE IN GROUNDWATER , 1987 .