Industrial Leachate Research Articles

Acquisition of a deliberately introduced phenol degradation operon, pheBA, by different indigenous Pseudomonas species.

Horizontal transfer of genes of selective value in an environment 6 years after their introduction into a watershed has been observed. Expression of the gene pheA, which encodes phenol monooxygenase and is linked to the pheBA operon (A. Nurk, L. Kasak, and M. Kivisaar, Gene 102:13-18, 1991), allows pseudomonads to use phenol as a growth substrate. Pseudomonas putida strains carrying this operon on a plasmid were used for bioremediation after an accidental fire in the Estonia oil shale mine in Estonia in 1988. The water samples used for studying the fate of the genes introduced were collected in 1994. The same gene cluster was also detected in Pseudomonas strains isolated from water samples of a nearby watershed which has been continuously polluted with phenols due to oil shale industry leachate. Together with the more frequently existing counterparts of the dmp genes (V. Shingler, J. Powlowski, and U. Marklund, J. Bacteriol. 174:711-724, 1992), the pheA gene was also represented in the phenol-degrading strains. The area where the strains containing the pheA gene were found was restricted to the regular route of phenolic leachate to the Baltic Sea. Nine Pseudomonas strains belonging to four different species (P. corrugata, P. fragi, P. stutzeri, and P. fluorescens biotypes B, C, and F) and harboring horizontally transferred pheBA operons were investigated. The phe genes were clustered in the same manner in these nine phe operons and were connected to the same promoter as in the case of the original pheBA operon. One 10.6-kb plasmid carrying a pheBA gene cluster was sequenced, and the structure of the rearranged pheBA operon was described. This data indicates that introduced genetic material could, if it encodes a beneficial capability, enrich the natural genetic variety for biodegradation.

Performance improvement of an unstable anaerobic leachate treatment system in an industrial waste landfill

Investigation on effects of temperature and HRT on the anaerobic biodegradation of an industrial waste leachate was carried out to improve the performance of an unstable field anaerobic process operated at the ambient temperatures. Maximum biodegradable COD fraction of the leachate was 36% at the mesophilic temperature. Stable COD removal at 35 °C was at least 1.2 to 1.4 times higher than those at the ambient temperatures, depending upon HRT. Temperature increase of the field anaerobic process to the mesophilic range was believed to be a competitive and practical option for the performance improvement.

Some Advantages of the Duckweed Test to Assess the Toxicity of Environmental Samples

AbstractIn Germany, wastewater legislation requires all municipal and industrial leachate to be subjected to toxicity tests. However, no phytotoxicity tests using higher plants are currently included among the standard tests. Freshwater microalgae have been used in most phytotoxicity tests and have often been considered as surrogates for higher plants. However, microalgae often do not show the same sensitivity as higher plants and have major disadvantages for the testing of unmodified environmental samples. In the following study, we evaluated the suitability of the giant duckweed Spirodela polyrhiza for assessing the toxicity of a municipal landfill leachate and two leachates of copper mining residue. Duckweed static toxicity tests were performed, and frond number was the endpoint used to calculate EC50 values. Symptoms of stress (chlorosis, necrosis, root destruction, and colony breakup) were also recorded. The landfill leachate was toxic with EC50;96h values ranging from 1.3 to 2.7% leachate (v/v). Toxicity of the copper slag leachate was largely determined by the elution method used. Leachate obtained using conventional German leaching methods (S4‐eluate) was not toxic to duckweed, whereas EC50 values for the pHstat4‐eluate ranged from 3.2 to 4.2% leachate (v/v). The results demonstrate the suitability of S. polyrhiza for the testing of unmodified wastewater samples and provide further evidence for the addition of a duckweed toxicity test to the standard tests conducted in Germany.

Periodic Processes for in Situ and On-Site Bioremediation of Leachates and Soils

Investigators at the University of Notre Dame's Center for Bioengineering and Pollution Control have conducted research and development studies since 1980 in the broad area of hazardous waste management. These efforts have been primarily directed at the use of periodic processes. Many of the findings have been applied to the construction and operation of full scale bioreclamation facilities. Early research and development activities were directed at the suspended growth, Sequencing Batch Reactor (SBR). The SBR is an activated sludge-like, periodic process that has been used effectively for the treatment of both domestic and industrial wastewaters (Irvine and Busch, 1979; and Irvine and Ketchum, 1989). Due to the time-oriented nature of the SBR, simple operational modifications have allowed for nutrient removal (Alleman and Irvine, 1980a; Alleman and Irvine, 1980b; Ketchum et. al., 1987; Irvine et. al., 1979; Manning and Irvine, 1985; and Palis and Irvine, 1985) and the control of bulking sludge (Brenner et. al., 1992; Chiesa and Irvine, 1985; Chiesa et. al., 1985; and Dennis and Irvine, 1979). The SBR has been shown to be a cost effective and energy efficient means of removing hazardous organic compounds found in industrial wastes and leachates from landfills (Brenner et. al., 1992; Herzbrun et. al., 1985; Irvine et. al., 1984; Irvine and Wilderer, 1988; Smith and Wilderer, 1987; and; Ying et. al., 1987). The Soil Slurry-Sequencing Batch Reactor (SS-SBR) described by Irvine et. al., (1993) and the Sequencing Batch Biofilm Reactor (SBBR), a fixed film periodic system that can be used in conjunction with granular activated carbon (Chozick and Irvine, 1991), were developed in the late 1980's and early 1990's. Recent efforts have been directed at periodically operated in situ bioremediation systems. This paper provides a brief overview of how such systems can be used to bioremediate contaminated leachates and soils.

Comparative assessment of the chemical and adsorptive characteristics of leachates from a municipal and an industrial landfill

Leachates from two landfills, one municipal and one industrial, were compared with respect to their chemical and adsorptive characteristics. Concentrations of most inorganic constituents were as much as an order of magnitude higher for the industrial leachate. The concentration of organic matter in that leachate, measured as total organic carbon (TOC), was more than two orders of magnitude greater than that of the municipal leachate. Gel permeation studies suggested similar molecular weight distributions for the organic fractions of the two leachates, but specific priority pollutants identified were different. The adsorptive characteristics of the waste samples with respect to activated carbon were evaluated using TOC as a lumped parameter expression of organic matter concentration. Adsorption equilibria and rates for the municipal leachate system were reasonably well described by treating TOC as a single component for modeling purposes. The industrial ieachate required a multicomponent approach. Ideal adsorbed solution theory was used in this case to characterize the behavior of a set of hypothetical TOC components. The approach was able to account, to some degree, for the competitive interactions evident among organic solutes comprising the mixture.

Interaction of Earthen Liner Materials with Industrial Waste Leachate

ABSTRACT The objective of this research was to study the effect of industrial waste leachate on the hydraulic conductivity of compacted clay soils of the type used in clay liners for waste landfill...

Pretreating landfill leachate with peat to remove metals

In this investigation, the capacity of peat to treat two different landfill leachates was determined. Freundlich isotherms showed that, for the tested metals (Cd, Cr, Cu, and Pb), an increased time of contact increased the level of adsorption over the entire range of influent values studied. In addition, metal interaction may play an important role in the adsorption of metals from leachate, as the various metal ions compete for the available adsorption sites on the peat. Column studies using two leachates, one from a municipal refuse fill (Al, Ca, Cd, Fe, Mg, Na, and Pb), and one from a fill which receives mainly oil and fly ash (Al, Ca, Cr, Fe, Mg, Mn, Na, Pb, and V), were conducted to establish design parameters for full-scale design. The efficiency of treatment was evaluated as a function of factors important for developing filter design criteria. Further considerations were given to filter longevity and ease of replacement, as well as for the ultimate disposal of the peat from the filters. For the municipal leachate a compaction density of 0.12 g mL−1 gave the best results as clogging occurred at higher densities, whereas 0.18 g mL−1 provided the best removal for the industrial leachate. While peat is incapable of adequately removing metals to acceptable levels for direct discharge, peat can provide substantial removal as a pretreatment process at low hydraulic loadings. Desorption of up to 50% was found when deionized water was applied to spent columns so ultimate disposal of the peat would require a dry environment.

Heavy metals in landfill leachate

Results based upon bench/laboratory and pilot‐scale studies reveal that both biological (aerobic and anaerobic) and physico‐chemical processes are feasible for the removal of leachate heavy metals. The aerobic process was shown to be superior to the anaerobic process. The process of adsorption was found to be superior to the ion exchange. The advantage of physico‐chemical processes over the biological process is that the former can handle excessively high concentrations of heavy metals in the influent without the detrimental effect of toxicity. Research conducted at NJIT with fly ash and clay sorbents for the removal of heavy metals from industrial sludge leachates showed these materials to be effective with the controlled flow rates and sorbent arrangements.

Comparative toxicity of solid waste leachates to Daphnia magna

The comparative acute and chronic toxicities of municipal, industrial, coal-fired power plant, and synthetic fuel solid waste leachates to the aquatic invertebrate Daphnia magna were determined. Seventeen leachates were laboratory-derived by extraction with 0.5 N acetic acid, and one, an arsenic-contaminated groundwater, was naturally derived. The acute toxicity 48-h LC 50 estimates (concentrations of the test materials that killed 50% of the test organisms in 48 h) ranged from 0.0005% for a dye waste leachate to > 100% (i.e., undiluted) for a coal gasification waste leachate. The most toxic leachates were derived from a dye waste, a plater's waste, and the arsenic-contaminated groundwater, and the least toxic were from a soybean process cake waste and a coal gasification waste. Of the 16 leachates used in the 28 day chronic toxicity tests, only the arsenic-contaminated groundwater and a municipal sewage sludge significantly affected D. magna reproduction. The former material at 1.0% concentration and the sludge at 0.1% caused about an 88% reduction in the numbers of young produced by exposed females compared with controls. Generally, the industrial waste leachates were more toxic than those from the power plant and synthetic fuel wastes. Because its presence in the test materials interfered with interpretation of the results, acetic acid may not be an appropriate extraction medium for preparation of leachates.