Journal of Environmental Engineering

Managers and regulators need to determine the feasibility of expanding aquaculture in freshwater and marine systems without endangering the environment or compromising water-quality goals. Models for various aquaculture operations and receiving water responses have been developed and applied by previous researchers. However, these models should be combined into a single, unified framework prior to management applications. This paper demonstrates for the first time how various submodels can be integrated and used to calculate the impacts of aquaculture on river water quality. A fish bioenergetics submodel simulates fish growth, production, and by-product nutrient loading as a function of fish numbers, feeding rate, food composition, and temperature. A receiving water submodel simulates water-quality impacts as a function of the aquaculture by-product nutrient loading and the physical, chemical, and biological characteristics of the stream or river. The utility of the approach and proof of concept is demonstrated by examining the impacts of a hypothetical aquaculture operation on one of the United States’ most renowned, high-quality recreational trout fisheries, the Au Sable River (Michigan). This framework is used to evaluate the water-quality impacts of alternative fish production levels and quantify how careful control of ration and low phosphorus-content feed can reduce by-product nutrient loads. The model can also calculate how wastewater treatment can be used to increase the probability of attaining compliance when conscientious aquaculture management practices alone are insufficient to meet water-quality goals. Issues related to model reliability and validation are discussed and recommendations for future research and development are suggested.

Bioremediation is generally viewed as a cost-effective and sustainable technology because it relies on microbes to transform pollutants into benign compounds. Advances in molecular biological analyses allow unprecedented microbial detection and are increasingly incorporated into bioremediation. Throughout history, state-of-the-art techniques have informed bioremediation strategies. However, the insights those techniques provided were not as in depth as those provided by recently developed omics tools. Advances in next-generation sequencing (NGS) have now placed metagenomics and metatranscriptomics within reach of environmental engineers. As NGS costs decrease, metagenomics and metatranscriptomics have become increasingly feasible options to rapidly scan sites for specific degradative functions and identify microorganisms important in pollutant degradation. These omic techniques are capable of revolutionizing biological treatment in environmental engineering by allowing highly sensitive characterization of previously uncultured microorganisms. Omics enables the discovery of novel microorganisms for use in bioaugmentation and supports systematic optimization of biostimulation strategies. This review describes the omics journey from its roots in biology and medicine to its current status in environmental engineering, including potential future directions in commercial application.

Hydrolysis is arguably the least understood and least defined process in anaerobic biodegradation. In municipal wastewater treatment, it is associated with the degradation of organic particulates, soluble macromolecules, extracellular polymeric substances, and soluble microbial products. This paper reviews previous hydrolysis studies, emphasizing their interrelationships in an overall hydrolysis framework. Different methodologies adopted for hydrolysis assessments are also assessed, providing the basis for future hydrolysis studies. Finally, a unified theory and model, constructed by integrating the independent studies and reconciling their disparities, is proposed as an alternative to preexisting frameworks. As hydrolysis is an extracellular enzymatic process, this paper incorporates the enzymological aspects involved to elucidate its underlying principles.

Regarding the inability to fulfill regional landfill demands, the inefficiency of municipal solid waste management systems due to shortages of suitable and efficient infrastructures remains a crucial social issue. In addition, the fact that there are numerous environmental, social, and design factors that need to be taken into account by decision makers (DMs) raises serious concerns regarding the task of identifying appropriate sites for municipal solid waste landfills. For this reason, the use of multicriteria spatial decision support systems, the synergic combination of geographic information system (GIS) and multicriteria decision analysis (MCDA) methods, is proposed, taking into consideration the spatial nature of the problem and the need to incorporate conflicting objectives and DM preferences. The paper at hand proposes a framework that enables the implementation of the measuring attractiveness by a categorical based evaluation technique (MACBETH) method in GIS-based raster-driven suitability analysis. MACBETH is a well-established MCDA method for the evaluation of alternative actions/scenarios based on qualitative judgments regarding their attractiveness to a DM. A real-world case study concerning the placement of a landfill in the region of Thrace, northeastern Greece, is discussed in detail. The computational part of the MACBETH method is supported by the M-MACBETH decision support system. The proposed framework consists of an attempt that allows MACBETH implementation in GIS-based raster-driven suitability analysis. In addition, a comparative analysis with other well-known methods was conducted showing that the proposed framework produces sufficient results.

Molecular sieves and zeolites showed increased fluoride adsorption capacities when amended with aluminum (hydr)oxide (AlOOH). When normalized by the AlOOH content, the adsorption capacities of most amended molecular sieves were higher than the maximum theoretical value expected for monolayer surface coverage, suggesting fluoride removal from processes beyond adsorption, such as precipitation. Although the mass-normalized adsorption capacities of most amended materials were less than that of an equivalent mass of pure AlOOH, several molecular sieves with pores of 1 to several nanometers showed mass-normalized adsorption capacities similar to pure AlOOH, possibly due to their larger pores, which may have facilitated fluoride adsorption after aluminum (hydr)oxide precipitation. Energy-dispersive X-ray spectroscopy detected elevated fluorine in a representative AlOOH-amended molecular sieve after repeated fluoride adsorption, also consistent with fluoride uptake by processes beyond only monolayer coverage. Regeneration of the adsorbents with low-concentration sodium hydroxide solution led to partial recovery of the fluoride adsorption capacity, which decreased over the course of sequential adsorption batch experiments, possibly due to loss of aluminum.

The feasibility of using ion exchange resins in stirred (suspended) mode operation for the removal of natural organic matter (NOM) from surface water was investigated. Resins were compared in terms of their NOM removal capacity, kinetics, and regeneration efficiency under batch and consecutive batch loading conditions. The dominant mechanism for NOM removal with the strong basic A860 resin was ion exchange whereas a combination of ion exchange and surface adsorption governed the removal with the weak basic A847. The estimated limiting capacity ($q_m$) and the equilibrium constant ($\alpha$) for A860 were higher than the ones for A847, showing greater affinity of A860 for natural organic matter. Also, under consecutive batch loadings, the strong basic resin showed greater removal ($\sim 10\%$ higher) compared to A847. Different regeneration scenarios were also examined and A860 resin showed a superior regeneration efficiency ($\sim 20\%$) compared to A847. Overall, findings indicated the strong basic resin as a better candidate for the removal of NOM from surface water. This paper proposes an evaluation scheme for the selection of appropriate ion exchange resins aiming to reduce NOM in surface waters.

In response to industrial chemical spills that potentially contaminate drinking water and distribution systems, this study investigated sorption and desorption of odorous crude [(4-methylcyclohexyl)methanol] (MCHM) into polyethylene pipes, epoxy, or polyurethane linings, and granular activated carbon. MCHM sorption was compared to toluene and 1-butanol, which were investigated as reference contaminants. MCHM is the licorice-smelling industrial chemical that contaminated drinking water for over 300,000 West Virginians in 2014. For polyethylene pipes, MCHM diffusivity was $0.36–1.36\times {10}^{-9}{\mathrm{cm}}^2/\mathrm{s}$ and solubility was $0.003–0.008\mathrm{g}/{\mathrm{cm}}^3$. Sorbed MCHM readily desorbed from polyethylene into water at levels above the odor threshold. MCHM diffused more rapidly into epoxy at $35\times {10}^{-9}{\mathrm{cm}}^2/\mathrm{s}$, although its solubility was similar to that of polyethylene pipes. MCHM caused polyurethane to swell and deform. Granular activated carbon sorbed MCHM to below its odor threshold as determine by the Total Intensity of Odor method. Sorption properties of MCHM into polyethylene were similar to the polar contaminant 1-butanol and dissimilar to the nonpolar contaminant toluene, which is known to exhibit rapid diffusivity and high solubility.

This study was conducted to investigate the effect of biochar application on rice yield and greenhouse gases in nutrient-poor soil (NPS) and nutrient-rich soil (NRS). The treatment conditions for NPS and NRS plots were control (C), Ffertilizer (F), and sesame straw biochar + F (BC) treatments. The rice yields were higher in the order of $\mathrm{BC}(421.8\mathrm{g}{\mathrm{m}}^{-2})>\mathrm{F}>\mathrm{C}$ for the NPS plot and $\mathrm{BC}(802.4\mathrm{g}{\mathrm{m}}^{-2})>\mathrm{C}>\mathrm{F}$ for the NRS plot. ${\mathrm{CH}}_4$ flux with the NPS plot was similar to that of the NRS plot, whereas ${\mathrm{N}}_2\mathrm{O}$ flux in the NRS plot was greater than in the NPS plot in all tested treatments. The global warming potential in biochar application treatments was lower, with the global ${\mathrm{CH}}_4+{\mathrm{N}}_2\mathrm{O}$ fluxes decreased by 25.0–36.8% for the NPS plot and 16.7–39.4% for the NRS plot, compared with the corresponding other treatments. These results suggest that biochar application in NPS and NRS will enhance rice productivity and reduce ${\mathrm{CH}}_4$ and ${\mathrm{N}}_2\mathrm{O}$ fluxes.

Modeling the efficiency of arsenate removal at low initial arsenic (As) concentrations is a new challenge following the new maximum contaminant level (MCL) of As in drinking water, revised downward from 50 to $10\mathrm{\mu g}/\mathrm{L}$ by the U.S. EPA. Many water systems across the United States are required to remove As from drinking water under the current regulations. However, most of the models used to predict As removal performance were developed and validated based on the old, higher concentration standard. This paper investigates and reports on the ability of a model, based on the diffuse double-layer (DDL) surface complexation model, to predict As removal for low As levels ($10–20\mathrm{\mu g}/\mathrm{L}$). The model was validated with a pilot study using source water from Well No. 3 of the Mutual Domestic Water Consumers Association (MDWCA) in Anthony, New Mexico. Based on the comparison of experimental data with model results, the model presented here can successfully predict the efficiency of As removal by coprecipitation with iron (hydr)oxide when initial As concentration, total iron concentration, and pH are known. The average discrepancy between experimental data and predicted results ranged from 3 to 12%, as a function of conditions.

Aqueous chlorine (${\mathrm{Cl}}_2$, ${\mathrm{OCl}}^{-}$, ${\mathrm{Cl}}^{-}$) in combination with longer wavelength ultraviolet (UV) irradiation has been investigated as a potential advanced oxidation process (AOP) for water and wastewater treatment. The cases include bleaching of organic matter (NOM) and oil sands tailing pond water (OSPW) under sunlight irradiation. Surprisingly, low energy tail of ${\mathrm{OCl}}^{-}$ ($A_{\text{max}}$ at 290 nm) has been postulated to be responsible for degradation of organic components. An alternative photoreaction, potentially more photon efficient, postulates absorption by strongly absorbing chromophores of target compounds present in water, which then undergo reaction in their excited states. This alternate hypothesis was tested in the current study under 440 nm light-emitting diode (LED) irradiation, where chlorine species have no absorption, using Swannee River fulvic acid (SRFA), an oil sands process water, and by bleaching of a coumarin dye. All results show substantial enhancement of hypochlorite oxidation processes under irradiation of the various complex mixtures of organic chromophores at 440 nm, where chlorine species offer no measurable absorbance that can compete with the organic chromophores in the complex mixtures. In the fulvic acid case, a known long-lived triplet excited state is a plausible active species that may be a contributor.

Microalgae have been well recognized as one of the clean and renewable biomass energy resources. Codigestion using different cosubstrates has been shown to improve the anaerobic digestibility of microalgae and increase the biogas yield and methane content. This study investigated the effectiveness of using septic sludge as a cosubstrate to anaerobically digest microalgae. After 30 days of co digestion at 35°C, the codigestion group (25% algae, 50% algae, and 75% algae) had an average biogas production of $547.3\pm 35.6\mathrm{mL}/{\mathrm{gVS}}_{\text{fed}}$, an amount that more than tripled the biogas production from the 100% algae group. The addition of septic sludge to the microalgae resulted in more favorable initial carbon to nitrogen ratios (C/N) (11:1 to 27:1), improved digestibility of algal biomass, and decreased hydrogen concentrations, which were directly related to the increased quantity and quality of methane produced. The results demonstrated the effectiveness of using septic sludge as a cosubstrate to anaerobically digest microalgae Chlorella sp. and enhance the biogas production.

One major concern of increased development is the proportion of directly connected impervious areas (DCIA) in urbanized watersheds. A cost-efficient opportunity to treat stormwater within existing residential and small-scale commercial developments is to disconnect roof gutter downspouts and direct impervious surface runoff over lawns. Four paired residential downspout disconnection sites in Durham, North Carolina, were studied to quantify volume and peak flow reduction. Hydrologic data were collected from January 22, 2013, to October 8, 2013. For each site, the performance of disconnected downspouts discharging water over existing lawn was compared for three varying factors: slope of lawn, length of run over lawn, and proportion of contributing roof area to receiving lawn area. Data were analyzed from approximately 60 storm events. Performance was evaluated by calculating volume reduction with and without the direct rainfall on the lawn, resulting in cumulative runoff volume reduction ranges of 57–99% and 49–99%, respectively. Findings indicate that this simple and inexpensive stormwater control measure (SCM) might be an important, yet heretofore minimally accounted for, tool to mitigate runoff.

The daily demand of demineralized water (DMW) in electrolytic galvanizing line (EGL) in China Steel Corporation (CSC) reached approximately $\mathrm{1,600}{\mathrm{m}}^3$ as the production line was fully in operation. However, the wastewater produced from the EGL was discharged into the cold-rolling mill wastewater treatment plant even though it had potential for reclamation. This study provides details of design and parameter optimization of a full-scale wastewater reclamation plant for the EGL. Three wastewater streams including hot water rinse, pickling rinse wastewater, and condensate water from the EGL were selected for reclamation. The full-scale wastewater reclamation plant was constructed to equip with coagulation, flocculation, sedimentation, and filtration for pretreatment, and electrodialysis reversal (EDR) and ion exchange (IX) processes for desalination. The pretreatment process can reduce the total iron concentrations in the wastewater from 40–70 ppm to $<0.1\mathrm{ppm}$ to protect EDR membranes from fouling. The EDR systems can reduce the conductivity of the pretreated wastewater from $\sim 800$ to $125\mathrm{\mu S}/\mathrm{cm}$ (i.e., $\sim 85\%$ desalination rate). The plant is capable of supplying $540{\mathrm{m}}^3/\mathrm{day}$ of reclaimed pure water to the EGL from selected wastewater streams with the total flow rate of $\sim 770{\mathrm{m}}^3/\mathrm{day}$ (i.e., $\sim 70\%$ recovery rate). The cost of the reclaimed water was cheaper than the DMW produced by regular processes in CSC. The annual saving of the reclamation system, including pure water cost and wastewater treatment cost, was more than 11.6 million New Taiwan dollars (NT$).

Permeable pavements allow stormwater to pass through the pavement surface, filtering out sediment and debris; over time, regular preventative maintenance will be needed to maintain the pavement surface infiltration rate (IR). IR testing is commonly used to determine maintenance needs and frequencies. ASTM standard methods may be used to measure permeable pavement IR; however, these tests can take hours to complete and require infiltrometers not readily available to maintenance contractors. A simple infiltration test (SIT) has been devised which (1) is conducted using easily acquired materials, (2) has a larger surface area (i.e., more representative of average pavement conditions), and (3) requires, on average, 72% less time to conduct than the ASTM test. ASTM and SIT methods were compared by conducting a total of 873 IR tests at the same locations on 12 permeable pavements in North Carolina, Ohio, and Sweden. Results showed that (1) a segmented linear relationship related SIT and ASTM-measured IRs; (2) the SIT and ASTM tests predicted approximately the same IR up to $250\mathrm{mm}/\min$; (3) the larger surface area of the SIT reduced the variability in measurements (average 40% less) compared to the ASTM method. The SIT took one-quarter the time to run, on average, making this newly-devised tool more efficient when assessing IR than ASTM methods, potentially saving maintenance personnel time and money.