The removal of radiological agents from a wastewater treatment plant that entered via the detonation of a radiological dispersive device (RDD) was investigated. Cobalt and cesium have been the focus of simulated RDD events and therefore were chosen as the radionuclides to be studied. The goal of the study was to determine the efficacy of using commercially available adsorbents to remove Cs and Co from wastewater. Based on adsorption experiments two adsorbents were chosen for further study: sorbent ATS was selected for Co and IONSIV (UOP, Des Plaines, Ill.) IE-911 was chosen for Cs. Both ATS–Co and IE911–Cs were modeled using the Langmuir isotherm. Co removal by ATS increased with increasing pH. Cs adsorption by IE-911 was not a function of pH directly but decreased with increasing pH due to the increased removal of other cations (e.g., calcium). Removals of Co and to a lesser extent Cs were not significantly affected by the presence of wastewater solids and dissolved organics. The level of mixing did not adversely affect ATS/Co or IE-911/Cs removal kinetics. ATS’s Co removal capacity was constant with temperature, whereas IE-911–Cs’s capacity decreased with decreasing temperature. Both ATS–Co and IE911–Cs removal kinetics decreased with temperature.

The use of renewable energy systems may be attractive to environmental professionals who are designing and operating groundwater cleanup systems because of potential cost savings and reduced greenhouse gas emissions. The energy demands of many remediation systems are relatively small, and wind turbines marketed for domestic use may be suitable for such applications. Collecting site-specific wind velocity data necessary for performance modeling may be cost prohibitive compared to the cost of the small wind turbine system. The feasibility characterization is also complicated by siting the wind turbine according to the location of the groundwater contamination rather than the location of the optimum wind resource. The use of non site-specific wind velocity data, such as that available from a regional database may be a cost-effective means for predicting wind turbine performance. Monte Carlo models were developed to compare wind turbine performance predictions calculated using remote wind velocity data to actual wind turbine performance at a Nebraska Superfund site. The Monte Carlo models may have applications at other sites and for wind turbines used to power other types of loads such as groundwater pumping or remote households.

A confined disposal facility (CDF) is being designed for $3.5\mathrm{M}{\mathrm{m}}^3$ of contaminated sediments dredged from the Indiana Harbor Canal at East Chicago, Ind. The sediment will be placed in two cells enclosed by earthern berms about $9\mathrm{m}$ tall and cover about $36\mathrm{ha}$ . The air registration for the facility poses limits on particulate emissions; however, very little is known of the potential for particulate emissions from hydraulically placed dredged material. Therefore, the purposes of this study were to (1) determine temporal wind erodibility of the sediments; (2) estimate potential particulate emissions from wind erosion during CDF operations; and (3) simulate emission control measures that allow the CDF to comply with allowable emissions. A composite sample of Indiana Harbor sediment was placed in outdoor sediment bins at Manhattan, Kan., and variations in sediment wind erodibility parameters were determined over a $22\text{month}$ period. In general, sediment erodibility increased with freeze/thaw cycling, but decreased during the summer. Next, the Hydrologic Evaluation of Landfill Performance and the Primary Consolidation, Secondary Compression and Desiccation of Dredged Fill models were used to determine periods when the CDF cell surfaces would be saturated. Finally, the Wind Erosion Prediction System model was used to estimate potential suspended particulate emissions from the CDF during unsaturated periods. Hydraulic placement of the sediments in the cells will result in a sand bed at the north end of the cells that needs to be stabilized to prevent abrasion of the downwind area. Even with the sand bed stabilized, the simulation results showed that additional erosion control would likely be needed. Snow fences, short barriers, and stabilized strips were simulated as potential erosion controls. The results showed any of these could provide adequate reductions in emissions to meet the target emission levels.

Shake flask reactors with different inocula were run for the treatment of chlorophenols present in wastewaters. The three different inocula were obtained from—sewage treatment plant, refinery effluent treatment plant (ETP), and paper mill ETP, respectively. The model compounds tested were 4-chlorophenol (4-CP) and 2,4-dichlorophenol (2,4-DCP). The three inocula have different levels of exposure to phenolic compounds. As the paper mill effluent has high level of phenolic compounds, and sewage has no phenolic compound, the inoculum obtained from paper mill ETP would have been acclimatized to some degree to phenolic environment. In our lab, the inocula were acclimatized to synthetic 4-CP and 2,4-DCP for several weeks at $30°\mathrm{C}$ in shake flasks. It was found that each inoculum demonstrated different specific activity in chlorophenols degradation. The inoculum from paper mill ETP yielded highest degradation rate for both 4-CP and 2,4-DCP. The effect of a biogenic substrate (glucose) concentration on the acclimatization of chlorophenols was also investigated. Glucose concentrations used in shake flasks were 1, 0.5, and 0%. It was observed that cultures acclimatized with 1% glucose concentration had shown maximum degradation rate. Degradation rate for 2,4-DCP was lower than that for 4-CP. The presence of greater number of chlorine molecules in 2,4-DCP must have contributed to higher toxicity level for the microorganisms. A mixed system comprising of 4-CP and 2,4-DCP was found to be more toxic compared to that obtained in an individual system.

A sequential anaerobic-aerobic bioremediation pilot test was performed to assess its viability for chlorinated ethenes and to determine scaling parameters for remedial design. Transect data were evaluated to determine the first-order degradation rate of trichloroethene (TCE). Because the Damkohler numbers were greater than unity, a single-well regression approach was used to estimate the sequential first-order degradation rates. The biostimulated degradation kinetics were influenced by competing electron acceptors and total organic carbon. First-order degradation kinetics were appropriate after the biomass population was stimulated and critical redox conditions were established. First-order degradation rate coefficients ( $\lambda$ ) were calculated for the anaerobic and aerobic degradation of TCE, cis-1,2-dichloroethene (cDCE), and vinyl chloride (VC) using regression analyses from predominant daughter products. In anaerobic groundwater, ${\lambda }_{\mathrm{TCE}}=0.084{\text{days}}^{-1}$ , ${\lambda }_{\mathrm{cDCE}}=0.037{\text{days}}^{-1}$ , and ${\lambda }_{\mathrm{VC}}=0.046{\text{days}}^{-1}$ adjacent to injection and ${\lambda }_{\mathrm{TCE}}=0.037{\text{days}}^{-1}$ and ${\lambda }_{\mathrm{cDCE}}=0.020{\text{days}}^{-1}$ further downgradient. In aerobic groundwater, ${\lambda }_{\mathrm{cDCE}}=0.036{\text{days}}^{-1}$ and ${\lambda }_{\mathrm{VC}}=0.11{\text{days}}^{-1}$ . The groundwater residence times required to satisfy regulatory limits were estimated for different conceptual remediation scenarios.

The objective of this paper is to study the deformation behavior of moist-compacted soil liners with and without inclusion of discrete and randomly distributed fibers for waste containment systems at the onset of nonuniform settlements in a geotechnical centrifuge. First, scaling considerations pertaining to simulation of discretely mixed fibers in a centrifuge are presented. A series of centrifuge tests were carried out by varying aspect ratio and dosage of fibers in a soil liner of $1.2\mathrm{m}$ thick and compacted at its standard Proctor compaction. Controlled in-flight simulation of nonuniform settlements in a centrifuge was carried out using a trap-door arrangement at $40\mathrm{g}$ . It was observed that the aspect ratio and fiber content has a significant affect in restraining cracks for a randomly reinforced soil liner at the onset of nonuniform settlements. In addition to centrifuge test results, flexural behavior of soil beams with and without discrete and randomly distributed fibers was evaluated in the laboratory to bring out significance of fiber content and aspect ratio. The analysis and interpretation of test results indicate the significant potential for fiber reinforcement to decrease and to retard soil crack potential in a randomly reinforced soil liner while retaining its hydraulic performance.

Sludges are inevitable products of wastewater treatment processes, which have to be managed efficiently to meet stringent laws and regulations being enforced day by day. Currently, there exist three major options for complete sludge management—control at source by process modification; improvement in handling, processing, and disposal, and reuse to produce value-added products. The source control and improvement in handling and disposal practices have been reviewed by various authors and it is actually sludge reprocessing to value-added products that holds the future key to sustainable management. Thus, the primary focus of this review is the value addition of sludge comprising recovery of different components and development of commercial products. The production of various value-added products, namely, soil amendments, construction aggregates, fuels, biotechnology products, biosorbents, and miscellaneous have been examined addressing the key issues of production method limitations, benefits, and possible field application.

Over the last four decades, a number of environmental indices including water quality indices and air pollution indices have been formulated and used. Usually, the indices are formulated based either on studies conducted by the indices’ developers, or are formulated based on the Delphi technique, which takes into account the opinion of experts. In 1970, Brown et al. used the Delphi technique to formulate a water quality index (WQI) for the National Sanitation Foundation (NSF) of the United States. However, it has been observed that the procedure followed for the formulation of the index does not accurately represent the opinion of the experts who responded to questionnaires. In this technical note, the shortcomings in the formulation of the NSF-WQI are brought out and possible improvements in the development of this index are presented.