Understanding the role of local and cross-boundary sources is essential in making sound decisions in mitigating the impact of contaminant. In this paper such spatial assessments of multiple sources of contamination in the Passaic River Watershed was evaluated using a multimedia environmental model. Application of multimedia models could lead to informed management decisions for watershed contamination by providing a spatial and temporal distribution of contaminants and the relative importance of point sources, cross-boundary fluxes and environmental processes of the contaminants. An evaluation of trichloroethylene (TCE) release in the Passaic River Watershed was performed in this study through the assessment of its fate and transport using unsteady state and spatially variable multimedia modeling. This assessment was coupled with long-term analysis of releases to perform multiple scenarios of TCE releases, and to evaluate changes in current environmental concentrations within the watershed. The current multimedia model also assess the non-attainment of the watershed in regards to TCE contamination. Based on the release data that are currently available, attainment of TCE contamination would be reached for all subwatersheds except one. The influence of regional fluxes to the watershed contamination was quantitatively evaluated and shown for the Passaic River Watershed. The control of local releases of TCE was also evaluated to determine their effectiveness on reducing the watershed contamination. The local releases are shown to be important to the watershed contamination, and are found to be more significant than regional influxes of contaminants. Since there was no rigorous calibration of the proposed model due to lack of measured data, the model predictions should be used with care.

Centrifuge modeling of the long-term migration of light nonaqueous-phase liquids (LNAPLs) in unsaturated soils has been accomplished at a gravitational acceleration of $\mathrm{75g}$. When centrifugal gravity reached the desired $g$-level, synthetic gasoline was released from an underground storage tank and migrated into the unsaturated soils following a prototype time equivalent of 1, 5, and 10 years. After termination of the centrifuge test, soil samples were gathered using sampling tubes to determine the spatial distribution of various constituents of the gasoline through gas chromatograph analysis. The centrifuge tests adequately simulated gasoline migration processes in subsurface systems. The test results show that gasoline infiltrated the vadose zone and moved downwards, forming a high concentration zone above the water table and then spreading out laterally. The concentrations of benzene, toluene, ethylbenzene, and xylenes (BTEX), which represent the main components of gasoline, decrease with time, and gradually extend to a further distance. The water solubilities of BTEX affect their individual migration patterns and concentration distributions in unsaturated soil. In addition, soil properties influence gasoline transport behavior.

Modernization of municipal solid waste (MSW) landfills needs basic environment protection furnished by base liner and cover systems. In an effort to help developed arid countries build safe MSW sites that are environmentally acceptable and cost effective, laboratory and field tests were conducted on the natural Kuwaiti calcareous sand, locally known as gatch, to study its applicability to liner and cover system. Laboratory test included permeability assessment using flexible wall permeability tests (ASTM D 5084). Permeability was assessed in the field by two-stage borehole permeability test (TSBs) (ASTM Z 2509Z). Laboratory results indicated that gatch sands are considered a low permeability soil when compacted at optimum moisture content and maximum dry density by the modified Proctor test. In the laboratory a permeability value as low as $4.0\times {10}^{-7}\mathrm{cm}/s$ was recorded. A field test program was conducted on both natural gatch deposits and compacted gatch pads. These field results suggest that in situ gatch deposits could be considered as a secondary barrier system beneath in the liner. Similarly, permeability values of compacted gatch were between $3.0\times {10}^{-5}$ and $17.0\times {10}^{-5}\mathrm{cm}/s$. Upon desiccation, permeabilities of compacted gatch decreased. On the other hand, drying and wetting cycles conducted on the test pads and in the lab have recorded increased permeability values.

Mitigating salt runoff at salt storage and salt truck maintenance facilities has become a concern for many state departments of transportation (DOTs), since their storm water discharge is found to pollute the environment. The use of nonstructural and structural best management practices (BMPs) are required to minimize the generation of liquid waste containing salt and to minimize the potential hazard caused by salt runoff. The regulatory requirements mandate appropriate disposal of treated salt runoff, which has instigated the need to use wash water to make salt-brine for salt prewetting and anti-icing applications. This paper discusses a novel approach to collect and treat the liquid waste containing salt based on an approach similar to the wastewater management practices used in vehicle and equipment washing facilities. Collected wastewater will be first made to flow through an oil–grit separator to remove hydrocarbons and organic material, then through an underground sediment–sand filter to remove sediments. Sediments and oil–grit free wastewater will be stored in a fiberglass underground holding tank, until it is reused during the next winter storm. The salt–brine used for prewetting salts and for anti-icing is the eutectic solution with 23% salt, by weight. Salt solutions with low concentrations can be used as the base solution for making salt–brine, though it has to be intermittently stirred to prevent bad odor. The proposed measures may reap significant cost-savings, which otherwise would incur in treating wastewater prior to disposal.

A technique to quantify the leachate pollution potential of landfills on a comparative scale using an index known as the Leachate Pollution Index (LPI) has been developed and reported elsewhere. The LPI is a quantitative tool by which the leachate pollution data of the landfill sites can be reported uniformly. It is an increasing scale index and has been formulated based on the Delphi technique. The formulation process involved selecting variables, deriving weights for the selected pollutant variables, formulating their subindices curves, and finally aggregating the pollutant variables to arrive at the LPI. The aggregation function is one of the most important steps in calculating any environmental index. If the aggregation function is ambiguous, the result will raise an unnecessary alarm, indicating a comparatively less polluted environmental situation as more contaminated. Similarly, if the aggregation function is eclipsed, a false sense of security may be created, indicating a highly polluted environmental situation as less polluted. In this paper, the concept of LPI is described in brief and the various possible aggregation functions are described and used to calculate LPI values for an actual landfill site to select the most appropriate aggregation function. Based on the results, it is concluded that the weighted linear sum aggregation function is the best possible aggregation function for calculating LPI. Sensitivity analysis of the six short-listed aggregation functions is performed to substantiate this conclusion.

In the 21st century, no business can successfully operate in an economic and social vacuum. Enterprises can achieve enduring success only by meeting the needs and the expectations of all their key constituents: customers, investors, employees, and the greater society. Sustainable development (SD) demands attaining the three-dimensional balance between economic growth and social and environmental responsibility; therefore, sustainability entails the continuous fulfillment of the varying needs and sometimes-conflicting objectives of the multiple stakeholders. Cleaner production (CP) is a proactive environmental strategy, a step beyond waste handling or management (based on the “cradle-to-cradle” approach). It deals with the source of the problem (i.e., pollution prevention, $P^2$), rather than the effects and consequences (i.e., end-of-pipe treatment and/or corrective remediation). CP is also a practical approach of moving towards SD by allowing industries and service providers to produce more with less: fewer raw materials, less energy, less waste and emissions, and normally, less environmental impact and greater sustainability. CP, by definition, promises greater profits to industries by reducing costs (i.e., reduced material requirements, reduced disposal fees, and reduced environmental liabilities and cleanup costs) and by raising revenues through perhaps greater sales, exports, and better public relations (PR). CP has been applied to develop more environmentally benign (or even friendly) processes, products, services, and impacts. The implementation of CP involves specific methodologies for integrating environmental issues and sustainable development in a particular industry, employs applications of relevant analyses and syntheses, and above all challenges the traditional procedures for design, manufacturing applications, and services. This paper provides an overall view of CP as a concept, its principles, methods, and tools; its wide applications; and indeed its impediments. Several industrial examples of CP applications for conserving resources, minimizing wastes and emissions, reducing risks, and curtailing costs and generating profits are presented. Case studies from the chemical, textile, and cement manufacturing industries are illustrated. Through these examples it can be demonstrated that industry and the environment are not mutually exclusive but rather complementary in achieving SD.

Atmospheric corrosion is probably the most common form of corrosion and is defined as the corrosion or degradation of material exposed to air and its pollutants. This study essentially deals with atmospheric corrosion to assess the degrading effects of air pollution on various metals most used in engineering systems. This was the first ever corrosion study to be carried out in Oman concerning the influence of air pollution on atmospheric corrosion of metals. Common materials such as aluminum, brass, copper, epoxy, galvanized iron, mild steel, and stainless steel were used for the study. The selected sites of exposure were five locations where the metals were likely to be used. The results are discussed as functions of the type of test material, test location, environmental pollution factors, and exposure time. The results indicate that copper and mild steel are the most corrosive metals, while stainless steel, aluminum and epoxy are the least corrosive. Of the locations, Sohar emerged as the site with the worst corrosion record. Furthermore, higher concentrations of chlorides were observed in the Airport and Sohar areas, which are close to the seacoast. The highest carbonate sites were located in Al-Rusail and Sohar areas, these being more polluted industrial areas. Moreover, it was found that the atmosphere in the Al-Fahl area was polluted with sulphur compounds. In general, the results of this study can be used to obtain a corrosion fingerprint of the locations included herein.

A numerical model that determines the uptake of cadmium by plants grown to remediate contaminated soils is developed in this study. The numerical model is first applied to the problem of copper uptake from contaminated soils by poplar trees and the simulated results are then validated against published field data. In the numerical model, the one-dimensional Richards equation with a root extraction term coupled with the solute transport equation yields a set of partial differential equations that are solved numerically by a finite element technique. The cadmium uptake is assumed to follow Michaelis–Menton (Monod) kinetics. The nonlinear equations are solved using the Gauss elimination method to determine the temporal and spatial changes in moisture content and heavy metal concentration within the soil profile. The total amount of metal uptake by the plant roots is also computed. A comparison of simulated and field results of copper uptake by poplar trees shows that the model matches very well with the field data. The numerical model developed in this study can be thus used to predict the uptake of metals from soils using appropriate water extraction and the solute uptake functions.