Journal of Environmental Engineering

The objective of this research was to evaluate the nitrogen removal efficiency of a partially saturated vertical subsurface flow constructed wetland (VSFCW) used on university restaurant (UR) effluent treatment. The research was conducted in southern Brazil ($\text{latitude}:-23.304218$; $\text{longitude}:-51.172223$) on constructed wetland with $1{\mathrm{m}}^2$ of surface area, and the saturation layer was 0.25 m upper bottom. The results of this monitoring research extended for 6 months in a cultivated Heliconia rostrata system. The average applied loads were $37.6\mathrm{g}/{\mathrm{m}}^2$ of chemical oxygen demand (COD), $4.10\mathrm{g}/{\mathrm{m}}^2$ of total Kjeldahl nitrogen (TKN), $1.74\mathrm{g}/{\mathrm{m}}^2$ of ammoniacal nitrogen ($\mathrm{N}\text{-}{\mathrm{NH}}_4^{+}$), and $4.28\mathrm{g}/{\mathrm{m}}^2$ of total nitrogen (TN). The mean efficiencies of removal/conversion were 95.34% for COD, 96.95% for TKN, 93.99% for $\mathrm{N}\text{-}{\mathrm{NH}}_4^{+}$, and 69.39% for TN. The removed loads were $35.9\mathrm{g}/{\mathrm{m}}^2$ of COD, $3.98\mathrm{g}/{\mathrm{m}}^2$ of TKN, $1.68\mathrm{g}/{\mathrm{m}}^2$ of $\mathrm{N}\text{-}{\mathrm{NH}}_4^{+}$, and $3.02\mathrm{g}/{\mathrm{m}}^2$ of TN. The results showed system operational stability and the high efficiency on organic matter and TN removal of this effluent type.

The migration of invertebrates at each step of the treatment process in four waterworks with advanced treatment in eastern China was investigated for the first time. Raw water quality and water temperature had a strong effect on invertebrate abundance and species. A combination of sedimentation with pretreatment, ozonation, and disinfection was able to remove or inactivate the invertebrates. Enhanced sand filtration combined with chlorine or micro-coagulation effectively promoted the removal of invertebrates by filtration. Invertebrates colonized both down-flow and up-flow biological activated carbon (BAC) filters; thus, fixation of a BAC filter as the penultimate process before disinfection was inadequate. The addition of a persistent disinfectant before the clear water tank and regular flushing and washing of the clear water tank were essential. The total abundance of invertebrates in the clear water tank could be as high as ${10}^3$–${10}^4\mathrm{ind.}/{\mathrm{m}}^3$; rotifers and nematodes were the dominant species and accounted for 85.9–100% of total invertebrates. As a result, future studies should focus on the removal and control of rotifers and nematodes in waterworks.

One of the difficulties with habitat simulation methods for environmental flow determination is how to choose the minimum commitment point on the weighted usable area (WUA)–flow (Q) curve. For decades, considerable efforts have gone into finding a method that is objective and has biological sense. In Spain, the regulatory hydrologic planning code suggests taking a flow that produces a fixed percentage of the maximum WUA. Given the generalistic nature of this instruction, an evaluation based on environmental criteria needs to be considered. This paper proposes a test to assess the results obtained with the Instrucción de Planificación Hidrológica (IPH) criterion that can also be used to assess the results provided by other flow selection methods. The proposed test is based on the potential of the defined flows to allow fish movements. The results question the validity of applying a fixed percentage of the maximum WUA to determine the minimum flow on any river reach. They also allow the studied river reaches to be classified in groups with channels and basins of similar physical characteristics that can be taken into account for management purposes.

The groundwater at an abandoned industrial site located in Southern Taiwan has been polluted by mercury (Hg), which endangers human health and ecosystems. The objectives of this study were to (1) isolate Hg- and salt-tolerant microbial strains from the Hg-polluted site, (2) perform microcosm tests to evaluate the efficiency of ${\mathrm{Hg}}^{2+}$ reduction using the isolated strains, (3) determine the potential for enhancing the microbial reduction of ${\mathrm{Hg}}^{2+}$ using different media, and (4) apply a quantitative real-time polymerase chain reaction (PCR) technique to quantify and correlate the variations in merA (mercury reductase) concentrations during the Hg reduction process. Three bacterial strains were isolated and designated B7, A5, and A6, and these strains were able to grow well in media with 3.5% salinity. Of these strains, B7 had a salinity resistance that was greater than those of the other two strains. Strains B7 and A6 displayed acceptable Hg resistance, and they could sustain a ${\mathrm{Hg}}^{2+}$ shock as high as $100\mathrm{mg}/\mathrm{L}$ without significant inhibition in nutrient broth (NB) medium. The 16s rRNA sequencing of the strains revealed that Strain B7 was closely related to Enterobacter cloacae, and Strains A5 and A6 were associated with Pseudomonas sp. The results of merA gene quantification analyses revealed that the merA gene of the three strains could be induced by increased ${\mathrm{Hg}}^{2+}$ concentrations. Up to 92% ${\mathrm{Hg}}^{2+}$ removal was obtained in microcosms inoculated with Strain B7 and incubated in Luria-Bertani medium, given an initial ${\mathrm{Hg}}^{2+}$ concentration of $120\mathrm{mg}/\mathrm{L}$. The results indicate that there is potential to use the isolated Hg-reducing strains in the development of on-site or in situ bioremediation technologies for practical remediation of Hg-contaminated groundwater.

Groundwater contamination by mining effluents and spills at industrial sites often involves toxic metals and sulfate. Passive remediation systems, such as permeable reactive barriers, are attractive alternatives to traditional pump-and-treat. The rates of bacterial sulfate reduction for metals precipitation were assessed in three biocolumns assembled using sugarcane bagasse in natural form as the carbon and energy substrate for sulfate-reducing bacteria. An abiotic experiment receiving glutaraldehyde was assembled for comparison. An input solution containing 5,000–$\mathrm{6,004}\mathrm{mg}/\mathrm{L}$ sulfate, 10.0–$15.0\mathrm{mg}/\mathrm{L}$ zinc, and 10.0–$15.2\mathrm{mg}/\mathrm{L}$ nickel was supplied to the columns at $126.7\mathrm{mL}/\mathrm{day}$ for 145 days or 19.3 pore volumes of flow. From 30 to 145 days, pH increased from 5.5–5.8 to 6.8–8.0, the oxidation-reduction potential (ORP) declined from positive values to approximately $-400\mathrm{mV}$, sulfate concentrations declined by approximately $\mathrm{1,000}\mathrm{mg}/\mathrm{L}$, and metals (Zn and Ni) declined to nondetectable levels. Scanning electron microscopy with energy dispersive spectroscopy (EDS) confirmed Zn and Ni with S in the solid phase. The achieved rates of sulfate reduction spanned from 0.27 to 0.92 mg ${\mathrm{SO}}_4^{2-}/\mathrm{L}$ per day per initial gram (dry basis) of sugarcane bagasse, surpassing the maximum rate reported in the literature for a leaf-mulch, wood-chip, sawdust column. In contrast, the abiotic-column ORP remained at $+150\mathrm{mV}$, pH remained in the 5.5–6.5 range, and sulfate and phosphate underwent nonreactive transport. Also, nickel was not removed. On the contrary, measured Ni release was greater than the input concentration. For zinc, the data suggested adsorption onto bagasse, with breakthrough retardation. Sugarcane bagasse appears a suitable substrate for passive in situ groundwater cleanup in many areas of the world where this residue abounds.

This paper investigates the treatment of real petroleum refinery wastewater (PRW) using an electrochemical oxidation process. Direct anodic oxidation, an effective advanced electrochemical oxidation process (AEOP), was applied with different electrodes using a parallel-plate batch electrochemical reactor. The petroleum refinery wastewater originated from a national oil refinery for producing fuels, lubricants, and intermediates. Experiments treated wastewater samples of $500–510\mathrm{mg}/\mathrm{L}$ initial chemical oxygen demand (COD) concentration effluent flowed directly from the refinery to a physical treatment unit. Direct anodic oxidation, which is characterized by the generation of a hydroxyl radical (${\mathrm{OH}}^{•}$), can potentially destroy a wide range of organic pollutants. This paper studies several parameters: current density, initial pH, temperature, and the type of electrode. The kinetic study shows that high COD removal efficiency can be achieved following a pseudo-first-order reaction rate. The rate constants of oxidative degradation of organic pollutants by ${\mathrm{OH}}^{•}$ radicals are determined for different anode materials. Results reveal that the COD removal efficiency of 84.8% is obtained at pH 4.0, 25°C, and $50\mathrm{mA}{\mathrm{cm}}^{-2}$ using $\mathrm{Pb}{\mathrm{O}}_2$ anode, whereas COD removal efficiency of 86.3% is obtained at pH 7.0, 50°C, and $50\mathrm{mA}{\mathrm{cm}}^{-2}$ current density using a carbon felt anode. However, the highest COD removal is predicted at pH 4 and 55°C for most electrodes.

Pervaporative irrigation is a membrane technology that can be used for desalination and subsurface irrigation simultaneously. To irrigate, the tube-shaped polymer membrane is buried in soil and filled with water. Because of the membrane transport process, water enters the soil in the vapor phase, drawn across the membrane when the relative humidity in the air-filled pores is low. Soils are typically humid environments; however, the presence of hygroscopic compounds such as fertilizers decreases the humidity. For example, at 20°C the humidity in air in equilibrium above a saturated ammonium nitrate solution is 63%. Here, experiments showed that the presence of fertilizers in sand increased the water flux across the membrane by an order of magnitude. An expression for vapor sorption into sand containing different hygroscopic compounds was developed and combined with a model of vapor and liquid flow in soil. The success of the model in simulating experimental results suggests that the proposed mechanism, adsorption of moisture from the vapor phase by hygroscopic compounds, explains the observed increase in the flux from the irrigation system.

The objective of this study was to determine the erosivity index and to characterize the erosive rainfalls with respect to the far western region of Santa Catarina. Four meteorological stations were used to determine the rainfall erosivity based on the index of the product of the maximum rain intensity during a 30 min period and the kinetic energy of the rain (${\mathrm{EI}}_{30}$), and the equations were adjusted to estimate the ${\mathrm{EI}}_{30}$ value from the rainfall coefficient. Erosive rainfalls were classified, according to the pattern of temporal distribution, as Advanced, Intermediate, and Late rainfall pattern. The erosive rainfalls represent, on average, 83–88% of the annual precipitation, and the value of ${\mathrm{EI}}_{30}$ varies from 6,072 to $\mathrm{10,478}\mathrm{MJ}\mathrm{mm}{\mathrm{ha}}^{-1}{\mathrm{h}}^{-1}{\mathrm{year}}^{-1}$. The adjusted equations can be used to estimate the rainfall erosivity in places with only pluviometric data. Erosive rainfalls presented an average distribution of 51, 31, and 18%, respectively, of the Advanced, Intermediate, and Late patterns. The maximum rainfall intensity of 30 min with 20% of frequency ranged from 21.8 to $33.6\mathrm{mm}{\mathrm{h}}^{-1}$. For larger frequency, no significant variation was observed between the time distribution patterns.

Environmental regulators frequently stipulate the modeling approaches required for water utilities managing sewer networks to demonstrate regulatory compliance. The performance of drainage systems with regard to combined sewer overflow (CSO) discharges is required to be assessed using urban drainage models to prove compliance before large investments can be authorized. However, as far as the authors are aware, the modeling approaches to demonstrate regulatory compliance currently provide no opportunity for considering model uncertainty. This paper therefore addresses a knowledge gap in the role of model uncertainty in environmental compliance studies by describing an objective uncertainty quantification process that enables the water utilities to evaluate and report the uncertainty in their modeling predictions and that is also transparent enough to satisfy regulators. The sewer network was modeled in InfoWorks CS software using a design storm defined by the regulator to test the performance of CSOs. Uncertainty in the model and input parameters was propagated using Monte Carlo simulations with Latin hypercube sampling, and the results were presented to show the trade-off between the infrastructure investment and the risk of spilling.

Small hydropower plants (SHPs) may be considered the most cost-effective and environmentally benign technology for energy production. However, it has been suggested that the social–environmental impacts of SHPs could be reduced through improvements to the planning stage. This work aims to develop a geographic information system (GIS)-based framework to improve SHP planning in Minas Gerais State, Brazil, by providing site selection for development based on social–environmental restrictions. The framework used a GIS-based multicriteria decision analysis based on the analytical hierarchy process (AHP) to classify and weigh each attribute used. The results indicated that the number of planned SHPs is relatively high for Minas Gerais State (203), with the majority either in the Inventory or Project Assigned stages. The results also highlighted priority and nonpriority areas for SHPs by considering the likelihood of the SHPs causing the least and greatest socioenvironmental disturbances, respectively. The GIS-based framework has proved to be effective for improving SHP development in Minas Gerais State while suggesting site selection of priority areas that are likely to cause the least negative social–environmental impacts.

Developing highly potent and environmentally friendly catalysts to activate peroxymonosulfate (PMS) to generate reactive species has received considerable and increasing attention in the field of antibiotics elimination. In the present work, cobalt phthalocyanine (CoPc) supported by graphene oxide (GO) was prepared and used as a heterogeneous catalyst to activate PMS to generate hydroxyl and sulfate radicals for effective degradation of norfloxacin (NOR) in water. In this study, the CoPc/GO/PMS system had the advantages of the excellent performance of sulfate radicals generation and the reduction of cobalt leaching by the catalytic effect of GO delocalizing $\pi$ electrons. The optimum conditions for NOR degradation were 2.0% by weight CoPc/GO, catalyst dosage of $0.1\mathrm{g}/\mathrm{L}$, pH of 7, and PMS addition of $0.4\mathrm{g}/\mathrm{L}$. The analysis of intermediates indicated that the piperazinyl ring and fluorine atom of NOR were attacked by ${}^{•}\mathrm{OH}$ and ${\mathrm{SO}}_4^{•-}$ originating from CoPc activation in the CoPc/GO/PMS system. However, anions such as ${\mathrm{Cl}}^{-}$, ${\mathrm{NO}}_3^{-}$, and ${\mathrm{CO}}_3^{2-}$ in a natural water environment could inhibit the generation of reactive radicals, greatly affecting the removal of NOR. Meanwhile, the degradation mechanisms of NOR, including intermediate products, degradation pathways, and active species, were analyzed via liquid chromatography-mass spectrometer (LC-MS). It is believed that this work will promote the development of advanced oxidation technology based on PMS activation and the application of a heterogeneous catalyst in water treatment.

Electroplating wastewater must be properly treated before being discharged to the environment. A new type of evaporation system, called mechanical vapor recompression (MVR), was designed and studied in this paper. A series of experiments were performed to determine the evaporation and chemical characteristics of the wastewater. During MVR operation, the wastewater and treated water were sampled hourly at the monitoring points. The results showed that after the MVR evaporation, the chemical oxygen demand (COD) decreased from 5,450 to $550\mathrm{mg}/\mathrm{L}$, the average Cu content decreased from 55 to $0.5\mathrm{mg}/\mathrm{L}$, and the Ni and Zn contents decreased from 65 and $50\mathrm{mg}/\mathrm{L}$ to less than $0.2\mathrm{mg}/\mathrm{L}$. In addition, the evaporation was approximately $260\mathrm{kg}/\mathrm{h}$ at an evaporative temperature of 90°C and increased with increasing compressor frequency; the variation in the compressor power followed the same trend as the variation in the evaporation capacity.

Direct and indirect effects of climate change will have an adverse impact on water resources, human systems, regional agriculture, and food security. India, with a population of more than 1.2 billion, has experienced tremendous economic growth in the last two decades with only 4% of the world’s water resources and about 9% of the world’s arable land. Rainfall is distributed highly unevenly in the spatio-temporal space, with the highest rainfall-receiving region on the planet in northeastern (NE) India, in contrast to Thar Desert in western India. There has been a significant change in precipitation and temperature during 2000–2015 in India in comparison to the last 100 years. This could indicate a signature of climate change in India. We find that a comprehensive and detailed understanding and clear assessment of the impact of climate change on India’s water resources are required to reach a definitive conclusion and explanation of the trends to better inform policy actions.

Dioxins are well-known soil contaminants. Regulatory jurisdictions worldwide use regulatory guidance values (RGV) to help manage dioxin health risks. In the US, seven federal agencies, 41 states, and seven autonomous Native American jurisdictions have established values as have jurisdictions in at least 37 other nations. Dioxin soil guidance values are highly variable. The values for 2,3,7,8-tetrachlorbenzene-p-dioxin (or total dioxin expressed as TCDD) are well-dispersed over nearly 12 orders of magnitude from $4.91\times {10}^{-9}$ to $2.5\times {10}^3\mathrm{mg}/\mathrm{kg}$. The value spans for other dioxins and dioxin-like dibenzofurans are similar. The degree to which soil dioxin guidance value ranges can be attributed to uncertainty in direct contact cancer and noncancer risk models was analyzed. Based on bounded set uncertainty analysis, approximately 61% of the 304 TCDD RGVs identified fall within US Environmental Protection Agency risk model uncertainty bounds. Approximately 84% fall within noncancer risk model uncertainty bounds and, because the bounds overlap, approximately 60% could have been generated by either model. However, these bounds are conservative because they are based on improbable combinations of model coefficients. When Monte Carlo simulation was used to generate 95% confidence intervals, only 39% of dioxin RGVs fell below the upper bound at a target risk of $1\times {10}^{-6}$.

This study investigates the effect of slag on the mechanical characteristics of clay contaminated with ethanol gasoline (E10) by performing a series of unconfined compressive strength (UCS) tests. The effect of slag in four percentages of 0, 2, 4, and 6% (by dry weight) and three curing periods of 7, 14, and 28 days on clay contaminated with different E10 contents (i.e., 0, 3, 5, and 7% by dry weight) was examined. Additionally, 1% portland cement (PC) was added into all of the mixtures to keep the integrity of the untreated specimens and for ease of comparison. The compaction test results showed that the addition of E10 reduced the optimum moisture content ($w_{opt}$) and increased the maximum dry density (${\gamma }_{d\max }$), but that the addition of slag caused adverse behavior for the mentioned parameters. The analysis of the UCS results showed that increasing E10 reduced the peak UCS ($q_u$) values, but that the addition of slag and curing time was effective in improving the peak UCS values. The presence of oriented soil particles in a contaminated specimen was observed through scanning electron microscopy (SEM) analysis. The reduction of peak UCS values was confirmed to be due to the sliding behavior of soil particles induced by the viscose nature of E10. Additionally, observing a lower peak intensity value in the X-ray powder diffraction (XRD) pattern of the hydration products was another reason for recorded lower peak UCS values in contaminated specimens.

Fungi Penicillium isolated from synthetic polymers were investigated for their ability to degrade industrial or naturally occurring wastes such as paraffin, chitin, cellulose, leather, pectin, skim milk, sunflower oil, and starch. All the isolates grew quite well on paraffin. On the media with cellulose and leather, fungal growth reached 98%; on media with chitin, up to 58%. The use of the tested substrata shows that most of these fungi, isolated from materials hardly suitable to fungal nutritive requirements, can utilize different carbon (C) sources. This is especially true for Penicillium citreonigrum and P. oxalicum, which demonstrated good growth on paraffin, leather, and chitin. The fungi P. chrysogenum, P. spinulosum, P. verruculosum 2, and P. variabile also developed well on the majority of the substrata. These fungi can be considered good decomposers of materials occurring in nature as wastes.