clay and 4-cresol

Four identical pilot-scale landfill reactors with different alternative composite liners were simultaneously operated for a period of about 540 days to investigate and to simulate the migration behaviors of phenolic compounds (phenol, 2-CP, 2-MP, 3-MP, 4-MP, 2-NP, 4-NP, 2,4-DNP, 2,4-DCP, 2,6-DCP, 2,4,5-TCP, 2,4,6-TCP, 2,3,4,6-TeCP, PCP) and heavy metals (Pb, Cu, Zn, Cr, Cd, Ni) from landfill leachate to the groundwater. Alternative landfill liners of four reactors consist of R1: Compacted clay liner (10 cm+10 cm, k=10(-8)m/sn), R2: Geomembrane (2 mm HDPE)+compacted clay liner (10 cm+10 cm, k=10⁻⁸ m/sn), R3: Geomembrane (2 mm HDPE)+compacted clay liner (10 cm, k=10⁻⁸ m/sn)+bentonite liner (2 cm)+compacted clay liner (10 cm, k=10⁻⁸ m/sn), and R4: Geomembrane (2 mm HDPE)+compacted clay liner (10 cm, k=10⁻⁸ m/sn)+zeolite liner (2 cm)+compacted clay liner (10 cm, k=10⁻⁸ m/sn). Wastes representing Istanbul municipal solid wastes were disposed in the reactors. To represent bioreactor landfills, reactors were operated by leachate recirculation. To monitor and control anaerobic degradation in the reactors, variations of conventional parameters (pH, alkalinity, chloride, conductivity, COD, TOC, TKN, ammonia and alcaly metals) were also investigated in landfill leachate samples. The results of this study showed that about 35-50% of migration of organic contaminants (phenolic compounds) and 55-100% of migration of inorganic contaminants (heavy metals) to the model groundwater could be effectively reduced with the use of bentonite and zeolite materials in landfill liner systems. Although leachate contaminants can reach to the groundwater in trace concentrations, findings of this study concluded that the release of these compounds from landfill leachate to the groundwater may potentially be of an important environmental concern based on the experimental findings.

Topics: Aluminum Silicates; Anaerobiosis; Biodegradation, Environmental; Biotransformation; Chlorides; Chlorophenols; Clay; Cresols; Fresh Water; Kinetics; Metals, Heavy; Models, Chemical; Nitrogen; Nitrophenols; Phenols; Refuse Disposal; Water Pollutants, Chemical

The present paper describes an interaction study of phenol, o-cresol, and p-cresol with a rich-clay soil sample (clay content of 62.3%). Experiments performed using long contact times, in concentrations of 50.0 mg L(-1) showed practically no signal of phenol, o-cresol, and p-cresol after 48, 72, and 120 h, respectively, suggesting a sorption process. Sorption experiments in the period of 24 h were carried out with the phenolic compounds in concentrations between 5.00 and 500.0 mg L(-1), and negligible interaction between the phenolic species and the soil was observed. Additional experiments were carried out using HgCl(2) or NaN(3) solution as biodegradation inhibitors. After 10 days of contact time in the presence of inhibitors, no alterations in the concentrations of the three compounds studied were observed, and the results suggest no sorption process, with the compounds being almost entirely biodegraded by the soil sample, or possibly the formation of nonextractable residues could occur.

Topics: Aluminum Silicates; Anaerobiosis; Biodegradation, Environmental; Bioreactors; Clay; Cresols; Hydrogen-Ion Concentration; Kinetics; Phenol; Soil; Solubility