Performance monitoring of applied remediation technologies is an important part of site remediation. It involves periodic measurement of site parameters to evaluate whether the remediation technologies perform as expected or to determine the termination date of remediation projects. Performance monitoring can be a difficult undertaking if there are no well-defined and measurable remediation objectives, such as a reduction in mass discharge rate from a contaminant source. Besides, the selection of the site parameters to be monitored is highly dependent on the remediation objectives established and the remediation technologies applied. For instance, contaminant concentration in soil, soil vapor, and groundwater within a contaminant zone should be monitored if reduction of the mass or volume of a contaminant zone is the prime remediation objective, while contaminant concentration in groundwater just outside a contaminant zone should be the main monitoring parameter if the objective is to mitigate the contaminant migration. Furthermore, subsurface temperature is a unique monitoring parameter for in situ thermal remediation to ensure the proper operation of the technology, whereas groundwater oxidant concentration is the monitoring parameter only for in situ chemical oxidation technologies. This paper mainly covers the general criteria for establishing the site-specific remediation objectives and the key monitoring parameters for various remediation technologies, which help avoid waste of efforts to collect unnecessary site parameters during the performance monitoring.

Polyblending was applied to mix waste fiber-reinforced plastic (FRP) and polyethylene (PE) plastic waste in various proportions and particle sizes. Compatibility, morphology, mechanical properties, and dynamical mechanical analyses of the matrix composites were used as indices to justify the physical behaviors of composites. Differential scanning calorimetry measurements and scanning electron microscopy observations showed that PE and FRP in the blends were incompatible. The mechanical strengths of blends were decreased if the FRP ratio or particle size increased. Results of tensile and impact strength tests indicated that the blends had a brittle property. The loss tangent $\left(\tan \delta \right)$ of dynamical mechanical analysis also increased with the increase of the FRP ratio and particle size. These results reveal a weakening interaction between the FRP and plastic matrix. As PE lost ability to cover FRP, external forces were unable to be transferred or dispersed properly across the composite matrix. This increased the tendency of the blends to fracture.

This study was conducted to investigate the effect of high cadmium loading on the performance of free water surface constructed wetlands under different environmental conditions. Influents were prepared by mixing the synthetic wastewater with ${\mathrm{CdCl}}_2\bullet {\mathrm{H}}_2\mathrm{O}$ at concentrations of 5, 10, 25, and $50\mathrm{mg}∕\mathrm{L}$ for each of the four simultaneous experiments during three runs. The performance of the wetland system was evaluated for three hydraulic retention times (HRT)—5, 7, and 10 days. Removal efficiencies of the soluble chemical oxygen demand were found to be in the range of 72–91% during the experimental period. The mean effluent cadmium concentrations varied between 0.17 and $12.73\mathrm{mg}∕\mathrm{L}$ . The overall average cadmium removal efficiency during the three runs ranged between 75 and 97%. Most of the cadmium was accumulated in soil (56–76% of total influent cadmium). Of the total cadmium uptakes, about 14–23% of the total cadmium intake was accumulated in bulrush plants. The accumulation in soil and in plants increased with influent loading during each run. The optimum HRT for efficient Cd removal from wastewater was found to be $10\mathrm{days}$ .

Trichloroethylene (TCE) adsorption onto soils is an important factor in the design and operation of reliable remediation systems for removing TCE. In this study, a simplified approach, consisting of headspace technique combined with spreadsheet method, was developed and used for determinations of the TCE adsorption coefficients of two typical soils in Taiwan: Taikang and Shoufong soils. The headspace technique, directly measuring gaseous TCE concentrations with gas chromatography was first performed, followed by calculating adsorption coefficient by spreadsheet method step by step performed on a personal computer. The Taikang soil had a linear adsorption coefficient $K_d,3.4\mathrm{L}∕\mathrm{kg}$ , and the Shoufong soil, $3.1\mathrm{L}∕\mathrm{kg}$ . This study demonstrated that the proposed technology has considerable application potential in soil investigation.

This study investigated the application of biomass gasification to generate renewable energy, using three different types of agricultural and forestal residues: rice husk, almond shell, and waste wood. The field work was carried out in a full-scale gasification plant in Jiangxi, China. The heat value of product gas and the environmental pollution impacts of different biomasses under different gasifying temperatures were studied. Under the carbon feed rate in the range of $200–400\mathrm{kg}\mathrm{C}∕\mathrm{h}$ and similar biomass moisture content, increasing carbon feed rate had positive effect on the concentration of carbon-containing fuel gas components $\mathrm{CO}$ and ${\mathrm{CH}}_4$ , whereas the concentration of ${\mathrm{C}}_n{\mathrm{H}}_m$ was not much affected. Another fuel gas component ${\mathrm{H}}_2$ was affected by the moisture content of the biomass as it was generated by hydrolysis. In addition, the mobility of trace elements in biomass during the gasification process was evaluated and correlated with the concentration of gas pollutants produced. Thus, the potential environmental impacts can be preliminarily assessed by the elemental analysis of feedstock and ash residues.

The research focused on the effects of radio frequency/microwave (RF/MW) radiation on the UAE population, measured their effects, identified their sources, and developed management processes to control the level of exposure. Investigations on the control of RF/MW radiation sources in the UAE have been carried out using similar approaches used in many developed countries and then compared their results with existing regulations applied by the RF authorities. New guidelines have been proposed for UAE environments. Many RF field measurements have been carried out at several locations in the UAE to determine whether there is potential exposure associated with the RF, investigating the protection procedure standards, exposure limits, as well as the adverse impacts on the people located near the facilities. The measurements carried out on global system for mobile communications base stations have concluded that all field-strength readings are below the maximum permitted exposure for the general public.

Cyanobacteria are a global problem as they are able to produce compounds which can compromise the quality of potable water. Of major concern are the microcystin toxins which in dissolved form are not well removed by conventional water treatment processes. This study showed that microcystin-LR (MCLR) could be effectively removed from water using laboratory biological sand filters with complete removals observed under a range of conditions, including various sand and water combinations, different initial MCLR concentrations, and also two different temperatures. Molecular techniques allowed for the isolation of a bacterium, from the biofilm of one of the filters, which was shown to contain $mlrA$ , a gene previously documented to be involved in the biodegradation of MCLR. This gene was also identified within the biofilm of two additional filters strongly suggesting that the removal of MCLR through the filters was through biological action.

A septic tank and soil absorption system (SAS) is a simple means of treating domestic wastewater using the filtration, sedimentation, chemical absorption, and biological characteristics of soil. Data obtained from countries, such as the United States and Australia, where on-site wastewater treatment is common, suggests that SAS have become a main application for on-site treatment. In this research, the performance of SAS was investigated through an outdoor pilot study and two laboratory tank studies. The treatment capacity of the outdoor pilot plant was $1.5{\mathrm{m}}^3∕\text{day}$ , and used alternating anaerobic and aerobic units. The objective of the pilot study was to verify the occurrence of nitrification and denitrification in the system. In the tank study, the first setup utilized capillary and siphonage mechanisms to change wastewater distribution within the filter bed. The effect of wastewater distribution on hydraulic loading, pollutant removal, and system reliability were then investigated. In the second setup, three different media (sand, gravel, and soil) were used to treat typical domestic wastewater to assess their removal of nitrogen and phosphorus-rich pollutants (including ammonia, nitrate, and TP). Last, three different hydraulic loadings were examined to investigate the maximum possible treatment loading. The pilot scale SAS experimental results show that through a batch system of anaerobic and aerobic units, the SAS was effective in removing nitrogen by nitrification and denitrification. In the pilot study, ammonia decreased by 76.0%, nitrate increased by 91.8%, and the sum of ammonia and nitrate decreased by 51.3%. Results from the water distribution test show that a minimum grain size of $2\mathrm{mm}$ should be used for the filter bed medium when capillary layers are used to distribute water. The hydraulic loading can be up to $50\mathrm{L}∕{\mathrm{m}}^2\text{day}$ for a well-constructed capillary and siphonage trench. Results from the test with different filter media show that sand is the best of the three media tested in removing nitrogen and phosphorus. For typical nitrogen and phosphorus concentration of domestic wastewater, the influent concentration had little effect on the rate of reduction when sand and gravel were used. For hydraulic loading, under the maximum loading chosen in this experiment, ammonia nitrogen and phosphorus removal of greater than 90% still could be achieved for sand and soil. We therefore believe that hydraulic loading in SAS can be further increased to reduce the treatment site area.

Ocean disposal of wastes such as dredged materials causes the concentrations of contaminants and some other water quality parameters in the water column to change. In this study, the STFATE (short-term Fate) system, a model developed by the U.S. Corps of Engineers for managing automatic dredging and disposal of the dredged materials, was used to model and simulate the deposition, dispersion, and accumulation of the dredged material disposed at an ocean site. Additionally, aerial photographs taken from a helicopter on dispersion of the disposed materials were used to calibrate and verify the modeling results for evaluating its applicability in predicting the influence of disposing dredged materials on the surrounding seawater quality. Simulation results indicate that after $4\mathrm{h}$ of ocean disposal, the dredged material showed negligible adverse influence on the seawater quality $(\mathrm{SS}=3–4\mathrm{mg}∕\mathrm{L})$ . Results of simulating the dispersion of dredged materials revealed that $20\mathrm{s}$ disposal duration resulted in smaller influence distance and range but a longer time for the seawater to recover to its original state. A longer disposal time of $\mathrm{1,200}\mathrm{s}$ would cause a larger distance and range of influence but a shorter recovery time. The verification results demonstrate that simulated values on the dispersion length, width, area and shape generally comfort to the trends of monitored data; the average error is around 27.8%.