Journal of Environmental Engineering

In this study, we explore the use of sulfonated poly(styrene-isobutylene-styrene) (SIBS) polymer membranes for the inactivation of Escherichia coli (E. coli) and Enterococcus faecalis (E. faecalis) in surface waters, particularly when cupric (${\mathrm{Cu}}^{2+}$) and ferric (${\mathrm{Fe}}^{3+}$) counter-ions were cross-linked to the sulfonic domains of the membrane. The antibacterial evaluation of copper-exchanged and iron-exchanged sulfonated SIBS was carried out by assaying the presence of E. coli and E. faecalis after the membranes were brought into contact with bacterial suspensions from certified bacterial strains and water samples from a natural surface water source. Overall, the cell viability results obtained suggest that copper-exchanged sulfonated SIBS successfully inactivated both pathogenic bacteria. Although the extent of inactivation varied depending on the water source, treatment time, and initial population of bacterial suspension, copper-exchanged sulfonated SIBS was more selective to E. coli and iron-exchanged sulfonated SIBS was more selective to Enterococci bacteria. It was also observed that the inactivation of E. coli was strongly influenced by the degree of sulfonation (DS) since it was found to be dependent on the quantity of the ${\mathrm{Cu}}^{2+}$ exchanged. Finally, the membranes showed roughness changes upon exposure to the bacterial suspensions; however, they continued to be effective upon reuse.

A novel powdered ash-treated pine biochar (PATB) was compared to powdered activated carbon (PAC) for the removal of dissolved organic matter (DOM) and organic micropollutants (OMPs) from deionized water (DI), raw surface water (SW), and treated wastewater (WW). PATB performance (capacity and kinetics) was the primary focus under realistic water treatment adsorbent doses ($<200\mathrm{mg}/\mathrm{L}$) and contact times ($<120\min$). For the removal of DOM, iohexol (IOH), sucralose (SUC), and sulfamethoxazole, PAC consistently outperformed PATB. For the more readily adsorbable OMPs carbamazepine, cotinine, DEET, and theobromine, removal by the two adsorbents was comparable. Dose-response and kinetic results for each adsorbent between SW and WW for DOM, IOH, and SUC were similar, as their initial dissolved organic carbon concentrations were diluted to the same range: 2.0–$2.2\mathrm{mg}/\mathrm{L}$. SUC was found to have a higher affinity for PATB in DI, but ultimate removal was still limited by its lower specific surface area compared to PAC ($\sim 500$ versus $\sim \mathrm{1,000}{\mathrm{m}}^2/\mathrm{g}$). Additional investigations included combined adsorbent treatment and projecting batch results to fixed-bed breakthrough curves for hypothetical full-scale granular activated carbon and granular ash-treated biochar adsorbers using both the homogeneous surface diffusion model and pore and surface diffusion model.

In recent years, the environmental contamination and ecological poisons of antibiotics have possessed great challenges for human health. Versatile methods have been developed in enhanced demand for high-efficiency selective removal of tetracycline (TET), in which molecularly imprinted composite membranes (MICMs) have gained wide attention for selective separation of TET due to their preferable selective recognition and separation performance. Herein, we described a simple two-step method for developing the MICMs by using TET as a template molecule, acrylamide (AM) as a functional monomer, ethylene glycol dimethacrylate (EGDMA) as a cross-linker, and azo-bis-isobutryronitrile (AIBN) as an initiator. Based on ample rebinding sites and strong affinity force, the as-prepared MICMs possessed high rebinding capacity ($20.15\mathrm{mg}/\mathrm{g}$) for adsorbing TET. The superior relative selectivity coefficients could also be achieved, which facilitated for TET adsorbed and separated. These results might be due to the design of tailor-made recognition sites for binding TET in the final application. The as-obtained MICMs showed potential applications for selective recognition and separation of TET from environmental contamination.

This paper presents analysis and estimation of the longitudinal dispersion coefficient, a key hydrologic parameter for transport of contaminants in rivers and streams. The longitudinal dispersion coefficient varies spatially in streams with changes in the hydrologic parameters, e.g., the cross-sectional width, depth, sinuosity, and velocity of flow. Many theoretical and empirical equations are reported in the literature. After a comprehensive review, 30 equations for prediction of the longitudinal dispersion coefficient were selected from published research. These equations were used in this analysis. Hydrologic data from 59 river reaches were used for estimation of the dispersion coefficient. The estimated values of the dispersion coefficient were compared statistically and graphically with the observed values. Results showed that sinuosity significantly impacts estimation of the dispersion coefficient. Computations that include sinuosity improve the performance of the dispersion equation. Observed and estimated values were compared, and the equations were ranked based on the accuracy of estimation. The nine top-ranked equations were used for field validation using the ICWater model. The Sahay equation provides the best results when used in the calculation of concentration in the advection dispersion equation.

Turbulence is inherent in clarification basin systems; turbulence is challenging to quantify, yet directly impacting particulate matter (PM) separation. In computational fluid dynamic (CFD), Reynolds-averaged Navier-Stokes (RANS) turbulence models are widely adopted for computational efficiency. However, the accuracy of RANS is less examined in clarification systems. RANS models without benchmarking can potentially cast doubt or false confidence for results. In this study, common RANS models are applied to steady-flow clarification. Results are examined against high-resolution large-eddy simulations (LES) by high-order spectral element method (SEM) Nek5000 and laser Doppler anemometry (LDA) for three deflector configurations: (1) one-sided, (2) two-sided, and (3) no deflector. RANS model’s relative mean differences with respect to LES ranges from 13.9% to 41.4% and 32.7% to 105.1% in streamwise and vertical velocities, varying with configurations. LES predictions were improved from RANS. LES and RANS differences transcend hydrodynamics and persist for PM. Across configurations, RANS models of PM separation are predominately lower than LES. RANS model variability is discerned across clarifier configurations, decreasing with increasing PM diameter.

In autotrophic nitrogen removal, heterotrophic denitrifiers compete for nitrite/nitrate with autotrophic denitrifiers in the presence of organic matter, leading to a decline in autotrophic denitrifiers. In this study, a combined process of hydrolysis and chemically enhanced primary treatment (CEPT) was used for sewage pretreatment that removed chemical oxygen demand (COD) but reserved total nitrogen (TN). When raw water was hydrolyzed for $19\min$, approximately 19% of TN was converted to ${\mathrm{NH}}_4^{+}─\mathrm{N}$ and amino acid in the hydrolysate, resulting in ${\mathrm{NH}}_4^{+}─\mathrm{N}$ and amino acid accounting for about 75% of TN in raw water. When ${\mathrm{FeCl}}_3$ and bioflocculant were added into the hydrolysate at a final concentration of 40 and $10\mathrm{mg}/\mathrm{L}$, respectively, approximately 70% of COD and approximately 89% of total phosphorus (TP) were removed from the hydrolysate. Finally, approximately 80% of TN in raw water was reserved primarily in the form of ${\mathrm{NH}}_4^{+}─\mathrm{N}$ and amino acid ($>90\%$), which could be directly or indirectly used for autotrophic nitrogen removal. Combination of bioflocculant and ${\mathrm{FeCl}}_3$ can save 9% of the cost when removes $1\mathrm{g}$ COD from sewage.

To find an efficient way to recover and reuse carbon from biosolids for biological nutrient removal (BNR) process enhancement in wastewater treatment plants (WWTPs), the study investigated three methods for sludge treatment and obtained three types of carbon sources with different specification: mechanical disintegration carbon source (MDCS), alkaline mechanical disintegration carbon source (AMDCS), and liquid of hydrolytic acidification after alkaline mechanical disintegration (AMDHCS). After 12 h of absorption (under anaerobic conditions) of these carbon sources with the Biofilm Bio-Nutrient Removal Carbon source regulated Phosphorus Removal (BBNR-CPR) biomass, the biodegradability of humic acid in the sludge supernatant was improved, and the improvement was enhanced by alkali/hydrolytic acidification pretreatment. Carbon sources prepared by different methods were suitable for different temperature environments. At room temperature ($25°\mathrm{C}\pm 1°\mathrm{C}$), MDCS with a short preparation time (8 min) and low specific energy consumption [$\mathrm{10,400}\mathrm{KJ}/\mathrm{kg}$ total suspended solids (TSS)] could be reused for BNR; however, the most effective carbon source at low temperature ($13°\mathrm{C}\pm 1°\mathrm{C}$) was AMDHCS, of which the nitrogen and phosphorus removal efficiencies were 48.6% and 100%, respectively.

Recent infrastructure failures in the United States have brought attention to the ways and extent to which water security is unevenly distributed in urban areas. For many marginalized communities, infrastructure interdependencies (e.g., water, wastewater, stormwater, transportation) have created significant vulnerabilities in the face of aging or inadequate water treatment and delivery systems. In these communities, cascading failures precipitated by environmental hazards such as flooding often propagate across multiple infrastructure systems, sometimes resulting in poor water quality and/or lack of access to water for significant periods. However, little is known about how specific environmental and social factors combine with water infrastructure vulnerability and interdependencies to create enduring infrastructure inequalities. This paper presents a geospatial vulnerability framework for identifying water infrastructure inequalities, using the City of Tampa, Florida, to demonstrate the framework. For this framework, we integrate geographic information systems (GIS) analysis of environmental hazards, a factor analytic model of sociodemographic data, and a network topology-based performance indicator for the water distribution network. The resulting framework models the environmental and social vulnerabilities, quantifies hydraulic vulnerability and infrastructure interdependence, and maps their distributions across the urban environment. We find that the highest levels of social and environmental vulnerabilities in Tampa are present in low-income areas and communities of color that have high hydraulic vulnerability and infrastructure interdependency, which creates pockets of low resilience capacity.

Aqueous film-forming foams (AFFFs) containing perfluoro-octane sulfonate (PFOS) were commonly used in fire trainings until the awareness of their toxicity started to increase in the 2000s. Our objective was to build a modeling framework for estimating groundwater pollution with PFOS, utilizing dual-permeability modeling still novel for groundwater studies. The framework was applied to an existing contamination site. According to the results, only 27% of PFOS released from the fire-training area reached the aquifer. Adsorption to unburnt fuels and removal via oil separation wells before discharging to the aquifer can substantially reduce the PFOS contamination of groundwater. Despite this, the PFOS concentration in a groundwater intake area 1.9 km from the pollutant source was predicted to exceed the limits set for drinking water, in contrast to earlier predictions based solely on monitoring. The study demonstrates the importance of modeling for groundwater management as the data on AFFF usage and composition, and on soil and groundwater contamination with perfluorinated compounds and co-pollutants typically are limited in terms of the spatial and temporal scale of contamination.