Journal of Environmental Engineering

Pervious pavement (PP) is an infrastructure material that can alter rainfall-runoff relationships, filter particulate matter (PM), and sequester runoff constituents. Beyond a measure of total porosity (${\varphi }_t$), less-commonly measured pore parameters and relationships thereof influence these phenomena. In this study, cementitious PP (CPP), used as a permeable surface for an exfiltration system loaded by runoff, was examined. X-ray tomography (XRT) was utilized to examine pore size and frequency, generate a total-to-effective porosity (${\varphi }_t-{\varphi }_e$) relationship, quantify pore tortuosity ($L_e/L$), and relationships for specific surface area (SSA), pore-size distributions ${(\mathrm{PSD})}_{\mathrm{pore}}$, and ${\varphi }_t$. Gravimetric analyses were used for SSA based on mass ${(\mathrm{SSA})}_s$ as well as validation of XRT porosity. Results indicate that ${\varphi }_t$ ranged from 10 to 30% while ${\varphi }_e$ ranged from 4 to 27%. Relationships for (${\varphi }_t-{\varphi }_e$), SSA, ${\varphi }_t$, and median pore diameter ($d_{50n}$) were represented with a power law model (PLM). Using ${\varphi }_t$ the ${(\mathrm{SSA})}_{pt}$ of pores ranged from 11,000 to $\mathrm{19,000}{\mathrm{m}}^2/{\mathrm{m}}^3$ while for ${\varphi }_e$, ${(\mathrm{SSA})}_{pe}$ ranged from 12,000 to $\mathrm{21,000}{\mathrm{m}}^2/{\mathrm{m}}^3$. XRT results show that the ${(\mathrm{PSD})}_{\mathrm{pore}}$ is hetero-disperse. ($L_e/L$) ranged from 2.9 to 5.9, compared to 1.4 for a monodisperse and uniform distribution of pore sizes. The $(L_e/L)\text{-}{\varphi }_t$ relationship and probability density function (pdf) of ($L_e/L$) were Gaussian. Beyond the common index of ${\varphi }_t$, these parameters are building blocks for infiltration, filtration, evaporation, storage, and reaction components of models such as the storm water management model (SWMM) and computational fluid dynamics (CFD).

An anaerobic fluidized-bed bioreactor (AFBR), consisting of a vertical acrylic tube containing polystyrene particles as a support material for microbial adhesion, was operated for an extended period of time to treat synthetic wastewater containing phenol as the sole carbon source, at progressively increasing concentrations of 50–$700\mathrm{mg}{\mathrm{L}}^{-1}$, corresponding to organic-loading rates (OLRs) of 0.12–1.67 kg chemical oxygen demand (COD) ${\mathrm{m}}^{-3}{\mathrm{day}}^{-1}$. The inoculum used was sludge from an upflow anaerobic sludge blanket reactor treating swine-manure wastewater. The AFBR was operated at a hydraulic retention time of 24 h at 30°C. The reactor performance was evaluated with respect to OLR and differences between influent and effluent phenol concentrations, COD, bicarbonate alkalinity, volatile acidity, volatile suspended solids and pH. The pH values varied between 6.59 and 8.21 over the operating period. The alkalinity concentrations of the influent and effluent were 180 and $294\mathrm{mg}{\mathrm{L}}^{-1}$, respectively. The system achieved phenol- and COD-removal efficiencies greater than 93% and 91%, respectively, indicating the high capability of the proposed system for degrading liquid effluents containing phenol.

A theoretical analysis is provided of the extent to which doses from ultraviolet (UV) reactors in series are additive. It is shown that UV reactors’ reduction equivalent dose (RED) depends on the sensitivity of the microbe, the limits of which are the minimum and average of the dose distribution for infinitely sensitive and infinitely resistant microbes. For complete interbank mixing between two reactors in series, the additivity of RED is preserved. For systems where there is a negative correlation between dose paths, the RED is greater than or equal to twice that of a single reactor. The converse occurs for positive correlation. It is proven that when a single reactor is validated with a microbe whose sensitivity is at least twice that of the target microbe, it is assured that two identical UV reactors in series will deliver a RED at least two times that of the single reactor.

This paper aims to investigate the emission characteristics during the thermal treatment of co-contaminated soils containing lube oil and heavy metals (Cd, Cr, Cu, and Pb). Experiments were conducted using a laboratory-scale bubbling fluidized bed combustor under various fluidization parameters including temperature (500–800°C), air velocity ($11.5–17.9\mathrm{cm}/\mathrm{s}$), and sand bed particle size (545–920 μm). The emission products from the system, including flue gas, fly ash, and bottom ash, were sampled, and the concentrations of heavy metals and organic pollutants (such as benzene, toluene, ethylbenzene, xylene, and polycyclic aromatic hydrocarbons) along with the metal leachability were determined. The average emissions were lowest at 800°C, air velocities were in the range of $13.7–17.9\mathrm{cm}/\mathrm{s}$, and sand bed particle diameters were 770–920 μm. Removal of more than 99% and 48–85% of lube oil and heavy metals, respectively, was observed. Portions of the heavy metals were vaporized and attached to the fly ash, while the residual heavy metal fractions in bottom ash were supposed the effect of particle aggregated during thermal treatment. The experimental results showed that all heavy metals were concentrated in the bottom ash due to particle agglomeration; therefore, the metals leachability was in accordance with the standards.

It is suggested in this paper that recalcitrant organopollutants can be degraded efficiently by a hemoglobin-catalytic reaction in the presence of hydrogen peroxide (i.e., ${\mathrm{H}}_2{\mathrm{O}}_2$). The catalytic mechanism was studied with 5-aminosalicylic acid (5-ASA) as a compound for oxidation. Various evidence suggests that the catalytic mechanism is very similar to those of horseradish peroxidase and lignin peroxidase. The catalytic intermediates are known to oxidize various chemicals, indicating that the intermediates of hemoglobin can nonspecifically degrade many different types of organopollutants. To prove the hypothesis, an attempt was made to remediate polycyclic aromatic hydrocarbon (PAH)-contaminated field soil. The results showed that 98.5% of the PAHs compounds were removed by Day 42 and that seven of the 16 PAHs compounds analyzed were not detectable by the end of the research reported in this paper. Therefore, hemoglobin-catalyzed technology can be considered as a novel technology for remediation of soil contaminated with hazardous organopollutants.

Identification of unknown pollution sources is essential to environmental protection and emergency response. This paper presents a moment-based method for identification of source location and quantity of accidental pollution along a river. The first two moment equations are derived through the Laplace transform of the variable residence time (VART) model. While the first moment in combination with observed data is used to determine the location of pollution source, the second moment in combination with observed data is employed to estimate the total mass (quantity) of released pollutant. The two moment equations are tested using 23 sets of conservative tracer injection data collected from 23 reaches in 5 rivers with the reach length ranging from about 3 to 300 km. Results show that the first moment equation is able to predict the pollution source location with a percent error less than 18% in general. The percent error involved in the estimation of the corrected total mass is commonly less than 20%. While developed and tested using conservative tracer data, the moment-based method can also be applied to tracking the source location of reactive pollutants, providing a simple yet effective tool for pollution control and environmental management.

Fluoroquinolones, such as enoxacin, are poorly removed by common sewage-treatment processes, leading to their discharge into the environment, where they have unknown, and potentially serious, impacts on plants and aquatic organisms. The aim of the research reported in this paper was to understand the degradation of enoxacin by direct UV (ultraviolet) photolysis and advanced oxidation processes (AOPs) involving ${\mathrm{UV}/\mathrm{H}}_2{\mathrm{O}}_2$ and photo-Fenton [${\mathrm{UV}/\mathrm{H}}_2{\mathrm{O}}_2/\mathrm{Fe}(\mathrm{II})$], which may provide an alternative method of removing this compound from water in a treatment plant. Aqueous samples of enoxacin (0.06 mM) were irradiated at 254 nm ($I_o=2\times {10}^{16}{\mathrm{photon}\mathrm{s}}^{-1}$). The presence of ${\mathrm{H}}_2{\mathrm{O}}_2$, as well as the addition of ${\mathrm{FeSO}}_4·7{\mathrm{H}}_2\mathrm{O}$ (photo-Fenton process) both resulted in faster degradation kinetics compared to direct irradiation, with all of these systems leading to significant mineralization of enoxacin [$>80\%$ removal of total organic carbon (TOC)] within 30 min. The kinetics for the degradation of enoxacin in the presence of natural organic matter (NOM) isolates were also evaluated. Analysis of reaction byproducts by liquid chromatography–mass spectrometry (LC–MS) suggested that photolysis of enoxacin results in hydroxylation, defluorination, and formation of a geminal diol. Proton nuclear magnetic resonance (${}^1\mathrm{H}\text{-}\mathrm{NMR}$; in ${\mathrm{D}}_2\mathrm{O}$) was used for further verification. In addition, the rate constant for the hydroxyl radical ($•\mathrm{OH}$) reaction with enoxacin was determined by pulse radiolysis studies to be $(5.91\pm 0.08)\times {10}^9{\mathrm{L}\mathrm{mol}}^{-1}{\mathrm{s}}^{-1}$. These results suggest that $•\mathrm{OH}$ may play an important role in the photoinduced removal of enoxacin from water, and these systems may be used to remove this compound in treatment plants.