Journal of Environmental Engineering

Accommodation providers produce large amounts of wastewater in laundering processes ($12–25\mathrm{L}/\mathrm{kg}$ of textile). The composition of this wastewater depends on the washing procedure. Between 2 and $100\mathrm{mg}/\mathrm{L}$ methylene blue active substances (MBAS), between 1 and $30\mathrm{mg}/\mathrm{L}$ total phosphorous, and up to $\mathrm{20,000}\mathrm{mg}/\mathrm{L}$ chemical oxygen demand (COD) have been reported. Many regions have regulated the concentration of surfactants and phosphorous that can be discharged into water bodies to a few milligrams per liter, due to the negative effects that these compounds can cause in the environment. Several techniques can be employed in laundry wastewater treatment, including coagulation, filtration, biological reactors, adsorption, or advanced oxidation processes. Frequently, a combination of the mentioned processes is needed to meet the desired water quality standards. Only a few studies have reported an economic assessment of the options employed for laundry wastewater reclamation. Lower costs have been reported for coagulation, biological reactors, and adsorption processes than for other treatments such as filtration techniques. Total treatment costs vary between ${€0.09/\mathrm{m}}^3$ (treatment with granular activated carbon) and ${€5/\mathrm{m}}^3$ (nanofiltration). Life cycle assessment (LCA) is important for decision-making when different alternatives can be applied. Few references include a LCA for laundry wastewater treatment. Electricity consumption has been reported as one of the main environmental hazards for laundry wastewater treatment: an equilibrium must be reached between energy consumption and the standards of treated water. Future works must lead with the full-scale application and long-term monitoring of general, cost-effective, simple, and environmentally friendly techniques for the treatment of industrial laundry wastewater.

At the interface of environmental health science and engineering with policy, programming, and practice, multiple actors and social processes support communication and decisions. Understanding this interface would help accelerate public health improvements and the effectiveness of interventions, especially in managing the contextual factors that lead to disparities in service provision, resource use, and health. Misconceptions about the uptake of evidence in decision-making often limit fault to the overly technical nature of research findings or the competing and frequently shifting priorities of policy makers. The most effective means to enhance the flow of evidence, however, is regular, structured, and inclusive two-way communication, where knowledge brokers (individuals or institutions) link scientists, engineers, practitioners, policy makers, and the public. Good practices for enhancing science application should be recognized and tailored for environmental health science and engineering. We recommend that (1) science application and interprofessional engagement be incorporated into higher education, (2) funding mechanisms ensure stakeholder engagement beyond the project cycle, (3) evidence synthesis be collectively supported, (4) common rigor and study quality measures be adopted for diverse study types, and (5) research into effective science brokering practices and outcomes be encouraged.

The goal of this research was to use and to validate different quantitative polymerase chain reaction (qPCR) assays to quantify the pertinent microbial populations in full-scale anaerobic digesters at municipal wastewater treatment facilities. Methanomicrobiales ($\sim 40\%$ of Archaea) and Methanosarcinales ($\sim 35\%$ of Archaea) were the most dominant methanogenic orders in the mesophilic anaerobic digesters, whereas the Methanobacteriales ($\sim 40\%$ of Archaea) were the most common in the thermophilic anaerobic digester. qPCR results were validated via comparisons with profiles of microbial community composition obtained by PCR-amplified 16S rRNA gene sequences. Exceptionally strong linear correlations ($P<{10}^{-10}$) were observed when comparing the microbiome profile with the qPCR results for Archaea, Methanomicrobiales, Methanosarcinales, Methanobacteriales, and Methanosarcinacea. In addition, core communities of both Bacteria and Archaea were observed in the mesophilic anaerobic digesters. This research demonstrates that monitoring microbial groups in full-scale anaerobic digesters is feasible via qPCR, providing the prerequisite tools needed to track and to understand microbial population dynamics in anaerobic digesters.

Volatile organic compounds (VOCs) absorption and desorption capacity of silicone rubber (SR) and silicone foam (SF) was characterized under shock loading conditions to evaluate their potential as VOCs absorbents in the printing industry. Specifically, the absorption and desorption of two target VOCs ($n$-nonane and toluene) were evaluated using columns packed with either SR and SF. The $n$-nonane absorption of SR and SF was $29.5\pm 11.2$ and $14.5\pm 2.9\mathrm{mg}\text{-}\mathrm{VOCs}/\mathrm{mL}\text{-}\mathrm{absorbent}$, respectively. The toluene absorption of SR and SF was $9.7\pm 3.1$ and $4.8\pm 0.4\mathrm{mg}\text{-}\mathrm{VOCs}/\mathrm{mL}\text{-}\mathrm{absorbent}$, respectively. In both cases, the absorbed VOCs could be completely desorbed. However, the $n$-nonane desorption rate was faster in the SR column, whereas the toluene desorption rate was faster in the SF column. Damping performance was evaluated by calculating the difference between the VOCs peak concentration at the inlet and outlet of the reactor packed with SR or SF under VOCs shock loading conditions. The damping efficiencies of $n$-nonane and toluene in the reactor packed with SR were 88%–89%, whereas those of the SF reactor were 89%–90% for $n$-nonane and 72%–77% for toluene. The results indicate that solid silicones are promising absorbents to reduce VOCs discharge concentrations and enhance the efficiency of current VOCs treatment procedures.

Sludge rheology is an important parameter for pumping, pipeline transportation, and dewatering. This study was designed to investigate the effect of adding iron powder (IP) to thermal hydrolysis pretreatment (THP) sludge and raw sludge on the rheological properties and dewatering performance before and after anaerobic digestion (AD). The rheological data of sludge were also fitted. The results showed that the apparent viscosity of sludge from the combination of IP and THP decreased after AD. The opposite phenomenon can be observed in digested sludge with the addition of IP alone. The Herschel-Bulkley (H-B) model was most appropriate for describing the flow behavior of digested sludge from the combined process, showing the decrease of yield stress (${\tau }_0$), consistency coefficient ($k$), and the increase of flow behavior index. The addition of IP can further improve the thixotropy of THP sludge after AD. However, the higher dosage of IP did not show an obvious advantage. The dewaterability of THP sludge with the dosages of IP (30 and $60\mathrm{mg}/\mathrm{g}$ volatile solids) after AD increased by 17% and 19% compared with raw sludge. Notably, the change of dewaterability and soluble chemical oxygen demand were all linear with the thixotropy of digested sludge, which demonstrated that rheological indicators could be a new method to evaluate the changes of physicochemical properties.

Nitrosamines have become a focus of considerable research because of their carcinogenicity and environmental universality. In this study, to effectively remove nitrosamines, biological activated carbon (BAC) was acclimatized by a nitrosamine-reducing bacterial strain, and zero-valent iron (${\mathrm{Fe}}^0$)-assisted BAC was used to degrade nitrosamines from aqueous solution. The influencing factors and degradation mechanism were investigated. Compared with activated carbon (AC), the removal efficiency of more strongly polar nitrosamines by BAC and $\mathrm{BAC}\_{\mathrm{Fe}}^0$ increased prominently (21.0%–32.3%), yet there was no change between BAC and $\mathrm{BAC}\_{\mathrm{Fe}}^0$. The highest ratios of nitrosamine degradation by $\mathrm{BAC}\_{\mathrm{Fe}}^0$ were 49.8%–99.0%, and degradation reaction kinetics conformed best to a pseudo-second-order model ($R^2>0.9269$). The rate constants $k_{\mathrm{obs}}$ for six nitrosamines ranged from $3.4\times {10}^3$ to 6.9 × 10⁵ (M · s)⁻¹. Additionally, the removal ratios and $k_2$ of the linear nitrosamines partially scaled with their molecular weight, $\mathrm{Log}{K}_H$, and $\mathrm{Log}{K}_{ow}$ ($R^2=0.5661-0.952$). All nitrosamines were degraded within $30\min$ under strong acidic conditions; the removal ratios increased by 11.2%−23.1% under anaerobic conditions, but were decreased by $\sim 10\%$ in the presence of humic acid. The primary degradation products were secondary amines, methylamine, formic acid, nitrate, and nitrite resulting from the reduction of ${\mathrm{Fe}}^0$ and biodegradation by the nitrosamine-reducing bacteria.

Calcination conditions in the catalyst preparation process have a significant influence on catalyst performance. To explore the optimal calcination condition of ${\mathrm{MnO}}_x/{\mathrm{Al}}_2{\mathrm{O}}_3$ catalysts for NO oxidation, a series of samples was prepared using the same support and active compound but under different calcination conditions. The catalytic efficiency of the catalyst was tested, and through characterization [X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FE SEM), Brunauer–Emmett–Teller analysis (BET), and Barrett–Joyner–Halenda analysis (BJH)], the effect of calcination conditions on the catalytic performance was analyzed and discussed. The results showed that the samples calcined at 600°C for 5 h had the best catalytic performance. At a reaction temperature of 450°C, the molar ratio of ${\mathrm{NO}}_2/\mathrm{NO}$ conversion was as much as 1.65. The high surface area, crystal phase, and crystallinity (the relative content of ${\mathrm{Mn}}_2{\mathrm{O}}_3$ is about 50%); the high content of lattice oxygen ${\mathrm{O}}_{\beta }$ (about 20.4%); and high dispersion of active sites on the ${\mathrm{MnO}}_x/{\mathrm{Al}}_2{\mathrm{O}}_3$ catalyst calcined at 600°C for 5 h led to its relatively high catalytic activity. Compared with traditional noble metal catalysts, the ${\mathrm{MnO}}_x/{\mathrm{Al}}_2{\mathrm{O}}_3$ catalyst prepared by the impregnation method has good application prospects because of its low material cost, simple preparation process, and superior catalytic performance.

Removal of low concentration NO in enclosed space by a new combined process incorporating vacuum ultraviolet (VUV)-induced oxidation and wet absorption process at room temperature was studied. Effects of NO initial concentration, gas flow rate, and humidity on NO conversion in the VUV irradiation process were first investigated. Subsequently, the absorption aqueous solutions were optimized, and the ${\mathrm{Na}}_2{\mathrm{S}}_2{\mathrm{O}}_3$ inhibitor was used in the wet absorption process in order to absorb the generated ${\mathrm{NO}}_2$. The results demonstrated that NO conversion was increased with the decreasing initial concentration and gas flow rate, and moreover, humidity had a promoting effect on NO oxidation because of the generation of hydroxyl radicals (·OH) under VUV irradiation. ${\mathrm{Na}}_2{\mathrm{SO}}_3$ solution was favorable for the absorption of ${\mathrm{NO}}_2$, and the NOx conversion can reach 85% at the initial stage, while it was decreased to 25% after 20 min absorption for the rapid free radical chain reaction nature between ${\mathrm{Na}}_2{\mathrm{SO}}_3$ and NOx. In addition, the ${\mathrm{Na}}_2{\mathrm{S}}_2{\mathrm{O}}_3$ inhibitor was chosen to suspend the presented rapid reaction, the removal efficiency of NOx was increased with the augment of the ${\mathrm{Na}}_2{\mathrm{S}}_2{\mathrm{O}}_3$ concentration, and it can be stabilized at 85% even after 4 h reaction with the ${\mathrm{Na}}_2{\mathrm{S}}_2{\mathrm{O}}_3$ concentration of 1.5%.

In this study, the feasibility of an anaerobic flat-sheet ceramic membrane reactor for sewage treatment was evaluated, and the membrane fouling mechanism and membrane cleaning methods were studied. The results showed that when the transmembrane pressure was greater than 35 kPa, the hydraulic retention time and temperature affected the membrane fouling by causing the microbial metabolism to produce extracellular polymeric substances and soluble microbial products. In addition, the surfaces of the initial, polluted, and cleaned membranes were analyzed using scanning electron microscopy, and the fouling mechanism of the flat-sheet ceramic membrane was analyzed. With the combination of physical and chemical cleaning, most pollutants on the membrane surface and pores were removed; however, a small amount of pollutants remained in the pores. The results showed that the cleaning methods were effective in controlling membrane fouling.

The application of nanocomposite materials in membrane bioreactors (MBRs) is attractive because of their great potential to enhance the filtration performance and antifouling. This study modified polyvinylidene fluoride (PVDF) ultrafiltration membranes using graphene oxide (GO) and sulfonation GO (SGO). The antibacterial properties of nanocomposite membranes were tested using three Gram-negative bacterial species (Pantoea agglomerans, Escherichia coli, and Pseudomonas graminis). The results showed that PVDF-GO and PVDF-SGO ultrafiltration (UF) membranes had significantly nontoxic properties ($>95\%$, significance at $p<0.0001$), indicating that it was innocuous to bacterial growth. On the other hand, the nanoparticles (NPs) (GO and SGO) had approximately 50% antibacterial activity based on the viability tests, disc diffusion, and TEM analysis. The performance of membranes was examined using a pure water prermeabilty flux test. The water flux of the PVDF-SGO membrane ($720{\mathrm{Lm}}^{-2}{\mathrm{h}}^{-1}$) significantly increased compared with that of the GO membrane ($428{\mathrm{Lm}}^{-2}{\mathrm{h}}^{-1}$). Furthermore, the PVDF-SGO membrane had a 65.2% removal of methylene blue (MB), indicating that the SGO incorporated in the membrane enhanced the absorption capacity of heterocyclic aromatic compounds such as MB. The nanocomposite membranes (PVDF-GO and PVDF-SGO) are more sustainable than the PVDF membrane and are promising materials for MBRs because they have higher permeability and absorption capacity, and re harmless to bacterial activity.

The seasonality of wastewater production is a challenge for biological treatment systems due to the seasonal variation of wastewater volume and contaminant concentration. This study assessed the performance of a microbial fuel cell (MFC) during changes in feed from winery wastewater (vintage season) to dog food (idle season). The $100\text{-}\mathrm{mL}$ lab-scale MFCs exhibited slightly different output power performance (410 versus $290\mathrm{mW}/{\mathrm{m}}^3$) with chemical oxygen demand (COD) removal of $84\%\pm 10\%$ and $88\%\pm 1\%$ with winery wastewater and dog food, respectively. COD removal occurred prior to a decline in voltage production. The COD removal and total electrical energy recovered per cycle were both linearly proportional to the initial COD of each batch when the COD was increased from 1,000 to $\mathrm{10,000}\mathrm{mg}/\mathrm{L}$. An increase in COD increased the duration of power output but not the maximum output power. The energy recovery per kilogram COD improved with increasing COD concentration in the wastewater up to $0.042\mathrm{kW}·\mathrm{h}/\mathrm{kg}$ COD removed. This study demonstrated the efficacy of MFCs to treat agricultural wastewater and how dog food could be used as an ideal alternative feed to maintain effective reactor performance during the idle season of a seasonal agricultural wastewater system.

This study evaluated the efficacy of quantitative polymerase chain reaction (qPCR) to monitor several pertinent bacterial populations in 25 different full-scale wastewater treatment bioreactors across 9 different system designs. All the bioreactors contained a substantial quantity of total bacterial biomass and denitrifying bacteria, independent of system design. In contrast, the quantities of ammonia oxidizing bacteria (AOB) and phosphate accumulating organisms (PAOs) measured by qPCR targeting the amoA gene and the 16S rRNA genes, respectively, from the Candidatus Accumulibacter lineage significantly correlated with system design. Bioreactors with short mean cell residence time ($<2\mathrm{days}$) had significantly lower AOB abundance than most of the other bioreactors (all pairwise comparisons $P<0.0001$, except for a membrane-coupled bioreactor). Similarly, bioreactors designed for enhanced biological phosphorus removal had significantly higher relative quantities of PAOs than did conventional systems ($P<{10}^{-18}$). In conclusion, these qPCR assays should be practically useful for monitoring full-scale wastewater treatment bioreactors, thereby helping to improve process performance.

A mechanistic simulation model predicting the response of water distribution systems (WDSs) operated with or without disinfectant residual toward accidental arsenic contamination is developed in this paper. The impacts of chlorination, chloramination, and organic loading to control the oxidation of arsenous acid [As(III)] and the adsorption/desorption of arsenic acid [As(V)] on/from iron pipe walls were simulated by applying the model to two real-world WDSs. The model predicted that during any As(III) contamination event, the arsenic spread in WDSs would engage conservatively in the absence of a residual disinfectant. Due to the swift reactions between chlorine and As(III), maintaining residual chlorine was recognized as an effective strategy to control the soluble As(III) levels. Chloramine was predicted to be less effective than chlorine in causing As(III) oxidation and subsequent As(V) adsorption onto the pipe wall. Besides, under the test conditions considered, the required chloramine dose in the source water had to be 10 times higher to produce equivalent effects in terms of As(III) depletion as the chlorine dose of $1\mathrm{mg}/\mathrm{L}$. The results presented that chlorine formation in chloraminated WDSs via the monochloramine hydrolysis mechanism contributes to $>99\%$ As(III) depletion inside the distribution pipes. Therefore, the paper recommends maintaining additional chloramine residual in chlorinated WDSs to control the As(III) spread during arsenic contamination events in the downstream sections.

This study involves a comprehensive rectification project for the aquatic environment of a black odorous river in Dongguan City, China. It employs a combined process treatment technology of pollution source control, in situ remediation of sediments, biological contact oxidation, forced aeration–biological agent combination, flowing water circulation, and landscape greening to remediate a heavily polluted river. The project has improved the traditional biological contact oxidation process and built a pond with a daily treatment capacity of $\mathrm{1,200}{\mathrm{m}}^3$ inside the river to perform in situ repair of the polluted water body. The results show that the pond can efficiently degrade ammonia nitrogen (${\mathrm{NH}}_3\text{─}\mathrm{N}$) and has a strong resistance to the impact loads of black odorous water. After the in situ remediation of the sediments, the pollutants were greatly reduced, and the average removal rate reached 56.03%. The tracking and monitoring of the combined process showed that the water quality index chemical oxygen demand in the later stage of the project was reduced from 187 to $25\mathrm{mg}/\mathrm{L}$, ${\mathrm{NH}}_3\text{─}\mathrm{N}$ was reduced from 19.46 to $1.67\mathrm{mg}/\mathrm{L}$, and total phosphorus (TP) was reduced from 2.51 to $0.32\mathrm{mg}/\mathrm{L}$. Simultaneously, the dissolved oxygen increased from 0.12 to $6.34\mathrm{mg}/\mathrm{L}$, and the transparency increased from 4 to 55 cm. This shows that the combined process is practical and effective and can efficiently remove pollutants such as organic matter, ${\mathrm{NH}}_3\text{─}\mathrm{N}$, and TP from water, providing a reference basis for the in situ treatment of urban black odorous waterbodies.

Current research on the fate and transport of per- and polyfluoroalkyl substances (PFAS) has primarily focused on point-source releases, with less focus on nonpoint-source releases, such as stormwater runoff. In this study, 51 PFAS were investigated in sediment collected from two locations at nine stormwater ponds classified by different land-use types. PFAS concentrations were then related to two different land-use disturbance indicators, the Landscape Development Intensity (LDI) index and the Florida Department of Transportation (FDOT) road type functional classification, to discern a potential metric for estimating PFAS burden by using the proximity to and different types of anthropogenic activity. Of the 51 compounds analyzed, 28 in total were quantified with concentrations ranging from 7.2 to $\mathrm{4,800}\mathrm{ng}{\mathrm{kg}}^{-1}$. Perfluorinated carboxylic acids were the most commonly identified class of PFAS, as perfluorobutanoic acid (PFBA), perfluorohexanoic acid (PFHxA), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUdA), perfluorododecanoic acid (PFDoA), and perfluorotridecanoic acid (PFTrDA) were all found at eight out of nine sites, as well as perfluorooctane sulfonic acid (PFOS), a perfluorinated sulfonic acid. Within the framework of this study, the LDI index did not appear to be significantly correlated to PFAS burden, whereby only the 0.4 km radius of the LDI weighted average resulted in a potential metric for the lowest PFAS contaminated sites (which had correspondingly low LDI weighted means). The FDOT functional classification was a better predictor across all sites for PFAS burden, in which a significant difference was found between the number of PFAS detected at rural and urban sites. Most notably, perfluorohexanoic acid (PFHxA) concentrations were found to be significantly different between rural and urban sites. Moving forward, the potential of utilizing road type functional classification should be explored as a predictive tool to help better prioritize stormwater pond monitoring for PFAS.