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The occurrence and removal of antibiotics (sulfamethoxazole (SMZ), sulfathiazole (SFI), sulfamethazine (SMA), trimethoprim (TMP), tetracycline (TC), oxytetracycline (OTC), chlortetracycline (CTC), and enrofloxacin (EFX)) using constructed wetlands (CWs) for treating livestock wastewater were examined. The levels of antibiotics in the effluents of the CWs were in the order of CTC, SFI, SMZ, SMA, TMP, OTC, EFX and TC, ranging from 47.98 to 6834.66 μg/L, respectively. There was an inverse correlation ( p < 0.0493) in the removal of between sulfonamide group (SMZ, SFI, and SMA) and tetracycline group (TC, OTC, and CTC) antibiotics in the effluents of the CWs, indicating that sulfonamide-type antibiotics were more effectively removed in the CWs. Sulfonamide-type antibiotics also have higher p K a values, resulting in more effective adsorption into negatively charged soils through electrostatic interaction. Sunlight photo-degradation experiment showed that EFX was effectively removed (70%) compared to other antibiotics. The microcosm adsorption experiment using wetland soils under biotic and abiotic conditions showed that antibiotics in the biotic system were more effectively removed than abiotic system, indicating that soil-mediated microbial degradation can be a major removal mechanism in the CW soils. The microcosm adsorption experiments using wetland plants ( Phragmites australis ) showed that the biotic system also removed sulfonamide-type antibiotics more effectively compared to the abiotic system. Our results suggest that the removals of antibiotics in the CWs are mainly mediated by biodegradation and adsorption onto soil and plants. Also, the physicochemical property can be the important factors in the removal of antibiotics in the CWs. Our results imply that the CW system can be used for the removal of antibiotics for treating livestock wastewaters. [ABSTRACT FROM AUTHOR]

A stormwater management system utilizing the mechanisms of sedimentation and filtration/infiltration was developed and constructed for the immobilization of suspended solids and heavy metal constituents (Fe, Zn, Pb, Cr, Cu, Cd, Ni) in runoff. Monitoring took place between May 2010 and November 2012 on a total of 24 storm events. This research on the fractionation of heavy metals in runoff and discharge of a stormwater system provided insight on the actual efficiency of the system and determined the implications for treatment of the particulate-bound and dissolved heavy metals in runoff. Results revealed that the partitioning of heavy metal load in runoff in either dissolved or particulate-bound were influenced by flow rate and total suspended solids load, and evident in high-intensity storm (rainfall-runoff event). On the other hand, the partitioning of heavy metal load discharge from the stormwater system was more apparent during the early period of discharge having higher variability in dissolved than particulate-bound heavy metal. Findings revealed that fractionation of heavy metals played an important role in the performance of the stormwater system; thus, must be considered in designing stormwater systems. For the stormwater system to be effective, it is recommended to design the system treating not only the early period of a storm (first flush criteria) rather until the peak part of the hydrograph (high flow rate where partitioning was greatest) from a load basis. [ABSTRACT FROM AUTHOR]

Given the importance of water quality in drinking water sources, the Korean Ministry of Environment is designing and instigating the total maximum daily load (TMDL) program for major large rivers. For the successful implementation of this program, nonpoint pollutants resulting from various land uses should be controlled. Especially, paved areas such as parking lots and bridges are stormwater intensive land uses because of their high imperviousness and high pollutant mass emissions from vehicular activity. Vehicle emissions from these paved areas include various pollutants such as heavy metals, oil, grease and particulates. This research was conducted to investigate the magnitude and nature of the stormwater emissions with the goal of quantifying stormwater pollutant concentrations and mass emission rates from a parking lot and a bridge. Two monitoring sites in Kongju city were equipped with an automatic rainfall gauge and an automatic flow meter for measuring rainfall, water quality and runoff flow. This study presents the concentration changes during storm occurrence and event mean concentrations (EMCs) in the parking lot and bridge. The first flush criteria, a new concept explaining the relationship between EMC and the first flush effect, is also suggested using dynamic EMCs. [Copyright &y& Elsevier]

Abstract: Highways are stormwater intensive landuses since they are impervious and have high pollutant mass emissions from vehicular activity. Vehicle emissions include different pollutants such as heavy metals, oil and grease, particulates from sources such as fuels, brake pad wear and tire wear, and litter. To understand the magnitude and nature of the stormwater emissions, a 3-year study was conducted to quantify stormwater pollutant concentrations, mass emission rates, and the first flush of pollutants. Eight highway sites were monitored over 3 years for a large suite of pollutants. The monitoring protocol emphasized detecting the first flush and quantifying the event mean concentration. Grab and flow-weighted composite samples, rainfall, and runoff data were collected. A new runoff model with four parameters was developed that to describe the first flush of pollutants for a variety of rainfall and runoff conditions. The model was applied to more than 40 events for 8 pollutants, and the parameters were correlated to storm and site conditions, such as total runoff, antecedent dry days, and runoff coefficient. Improved definitions of first flush criteria are also presented. [Copyright &y& Elsevier]

Total captured gross pollutants in stormwater runoff were monitored at six Southern California highway sites over 2 years. Gross pollutants were defined as larger than 0.5 cm and were classified into three categories. The gross pollutants were 90% vegetation and 10% litter. Approximately 50% of the litter was composed of biodegradable materials. Event mean concentrations and mass emission rates are presented. No statistically significant correlations of litter production were noted, although the event mean concentrations show an increasing trend with antecedent dry days and a decreasing trend with total runoff volume or total rainfall. The mass emission rates will be useful to estimate total litter production for developing total maximum daily loads. [Copyright &y& Elsevier]

The Han River is 469.7-km long and drains a 26 219-km2 watershed. The sediments in the river are highly polluted due to inputs from upstream tributaries as well as partially treated municipal wastewaters that are discharged to the river. The water quality and strategy for control are important because the river is the primary drinking water supply for the City of Seoul, as well as being a major source for irrigation and industrial water. The Jamsil submerged dam partitions the river to isolate an upstream area for drinking water, but also captures sediments. Samples from four sites were studied to determine sediment pollutant concentrations and phosphorus release rates. Phosphorus tends to desorb from sediments when the concentration of overlying water is less than 1.4 mg/l. Water column P concentrations range from 0.04 to 0.1 mg/l, which suggests that sediments will act as a P source. In a series of batch experiments, P was released at approximately 15–20 mg/m2 week in the winter (1–5 °C) and as much as 90 mg/m2 week in the summer (20–24 °C), and is also a function of pH and dissolved oxygen concentration. The sediment total phosphorus concentration, which averages 833 mg/kg, is evenly distributed among non-apatite-P (33%), apatite-P (32%) and residual-P (34%). An equilibrium model is proposed to describe release rate. [Copyright &y& Elsevier]

Climate change is receiving an ever-increasing attention due to the accelerated global warming. Undoubtedly, CO 2 from anthropogenic sources is the major contributor to this undesirable effect and thus, there has been a growing attempt to curb it. Utilization of biofuels to replace fossil fuels has been considered a viable method to mitigate CO 2 emissions. However, there has been some concern about the indirect greenhouse gas emissions from the production and consumption of biofuels, such as land-use change, carbon leakage, and biomass transportation. It was suggested that these indirect factors can increase the CO 2 emission and may offset the benefits of CO 2 sequestration from biofuel utilization. In this study, all these challenges in biofuel production have been comprehensively reviewed and the importance of using the agricultural residues for biofuel production in countries with high reliance on agricultural development has been emphasized upon. A case study for the utilization of the agricultural residues in the Great Mekong Subregion (GMS) for biofuel production has been presented and the carbon balance for different bioenergy production scenarios in five Southeast Asian countries has been calculated. The results of the regression models show that Thailand and Lao PDR have the highest and lowest amounts of biomass residues per unit mass crop, respectively, suggesting the substantial differences in the harvesting technologies and/or economics of those countries. The overall annual CO 2 sequestration potentials of the biomass for replacing gasoline through bioethanol production, and for substituting coal for power generation via anaerobic digestion and gasification have been determined to be approximately 104/ Tg and 488 Tg, respectively. It has been suggested that using the crop residues as feedstock for the second generation biofuel production without affecting the food market could indeed provide considerable carbon credits for sustainable agricultural development as the major industry in the developing countries. [ABSTRACT FROM AUTHOR]

Low impact development (LID) are prominent type of vegetated stormwater infrastructure that provides various ecosystem services, such as biodiversity, carbon storage, and improvement in air quality. This study investigated six LID technologies to assess SOC retention and factors influencing accumulation. Soil samples (0–20 cm depth) were analyzed using the Walkley-Black method, specifically focusing on wet oxidation. SOC stocks ranged from 18.5 to 66.3 t C/ha in the inflow and 18.6 to 79.1 t C/ha in the outflow, with SCW and TBF showing higher SOC due to root turnover, stormwater runoff, and media composition. This study found that vegetation and impervious catchments significantly influenced SOC levels. Trees exhibited higher SOC due to their extensive root systems and longer life cycles. Roads and parking lots had higher SOC from plant debris and hydrocarbons in stormwater runoff. SOC also varied seasonally, peaking in spring due to photosynthesis and decreasing in summer and autumn from increased microbial respiration. A complex relationship between SOC and soil physico-chemeical perameters were also investigated, with moisture content and total nitrogen being critical factors for carbon stocks. Overall, the results from this study are seen as beneficial in optimizing the design guidelines for LID technologies for carbon sequestration and green space expansion in urban areas. • Root turnover, stormwater runoff, and media composition were the most influencing factors for SOC storage. • Soil samples from LID technologies exhibited higher SOC stocks outflow section due to long-term deposition of sediment bound organic carbon. • SOC peaked in spring, with seasonal changes driven by plant growth and microbial activity. • Impervious surfaces like roads and parking lots stored more SOC compared to rooftops, due to the accumulation of organic matter and sediments in stormwater runoff. [ABSTRACT FROM AUTHOR]

Using total suspended solid (TSS) removal efficiency and hydraulic retention time (HRT) as design parameters a design guideline of a settling basin in a constructed wetland (CW) was suggested; as well as management of sediment and particle in the settling basin. The CW was designed to treat the piggery wastewater effluent from a wastewater treatment plant during dry days and stormwater runoff from the surrounding paved area during wet days. The first settling basin (FSB) in the CW was theoretically designed with a total storage volume (TSV) of 453 m 3 and HRT of 5.5 hr. The amount of sediment and particles settled at the FSB was high due to the sedimentation and interception of plants in the CW. Dredging of sediments was performed when the retention rate at the FSB decreased to approximately 80%. Findings showed that the mean flow rate was 21.8 m 3 /hr less than the designed flow rate of 82.8 m 3 /hr indicating that the FSB was oversize and operated with longer HRT (20.7 hr) compared to the design HRT. An empirical model to estimate the length of the settling basin in the CW was developed as a function of HRT and desired TSS removal efficiency. Using the minimum tolerable TSS removal efficiency of 30%, the length of the FSB was estimated to be 31.2 m with 11.8 hr HRT. [ABSTRACT FROM AUTHOR]

The effectiveness of presettling basins as component of stormwater best management practice (BMP) technologies was investigated. Storm event monitoring and sediment collection were conducted from May 2009 to November 2012 on the presettling basins of the three BMP technologies designed to capture and treat stormwater runoff from highly impervious roads and parking lots. Data on captured runoff and sediment, total suspended solids (TSS) loadings, rainfall and runoff rate, sediment accumulation rate, as well as particle distribution and pollutant concentrations of sediment were gathered and analyzed along with the physical design characteristics of the presettling basins such as surface area and storage volume. Regression models were generated to determine significant relationships between design parameters. Results revealed that the storage volume ratio (ratio of storage volume of presettling basin to BMP) was an important parameter in designing the presettling basin of the BMP. For practicality, optimizing the design of the presettling basin means that the storage volume ratio should be determined based on the desired captured amount of runoff and sediment from runoff to limit the frequency of maintenance caused by the accumulation of sediment. It was recommended that pretreatment of runoff should be employed when the site in which the BMP is to be sited has high TSS loading and runoff rate, and is subjected to high intensity rainfall. [ABSTRACT FROM AUTHOR]

The expansion of livestock industry resulted to larger waste production and pollutant deposition in the natural environment. Advanced treatment systems for treating wastewater and discharges from livestock areas are necessary to reduce the pollutant loads in receiving water bodies. This study mainly focused on evaluating the effectiveness of a livestock constructed wetland in treating composite wastewater discharge and stormwater runoff. Water and sediment samples were collected and analyzed to determine the factors that can potentially affect the performance of the facility. Positive pollutant removal performances for turbidity (52% to 81%), TSS (61 to 82%), organics (34% to 50%), and nutrients (10% to 48%) were noted in the CW for storm events and dry days due to the continuity of flow and adequate HRT conducive to pollutant removal. SLR models for pollutant removal efficiency yielded low r2 values (0.26 to 0.53) and high errors (6.85% to 31.45%) implied that the predictive removal efficiencies were not precise. Despite the significant decrease (p <.05) in pollutant concentrations after the treatment, water quality standards were still exceeded by the effluent from the CW. Further improvements in the design of CWs can be incorporated to achieve the desired water quality standards. The findings of this inquiry can be used to establish the factors affecting the treatment performance of CWs and formulate design guidelines to improve the treatment process. • Rainfall patterns influence the performance of a constructed wetland (CW). • The CW can significantly reduce pollutant loads entering natural water bodies. • Pollutant concentrations in the CW sediments passed the soil management standards. • Design improvements are necessary to comply with the water quality standards. [ABSTRACT FROM AUTHOR]

Low-impact development (LID) techniques are being applied to reduce non-point source (NPS) pollution which are generated from various land uses. Cost-effective LID design requires consideration of influent runoff properties as well as physical and ecological pollutant-removing mechanisms. However, current LID technology design has failed to reflect the different properties of influent water from various land uses, and the biological design factors in LID facilities causing low efficiency and difficulties in maintenance. This study was conducted to identify biological design factors by analyzing the impact of the pollutants included in influent runoff and physical environment on microbial growth in rain garden facilities applied to different land uses. The results showed that the non-point source pollutant loadings were about 1.5–3 times higher in the runoff from parking lots, which are frequently visited by automobiles than in roof runoff. Type of soil, chemical species, and chemical composition were assessed as internal environmental factors having significant impact on the phylum and the count of microorganisms in the facilities. The growth of Cyanobacteria, Streptophyta, Chlorophyta, Bacillariophyta, and Xanthophyceae was good when there was appropriate water content in the soil, light, and sandy soil. Based on these results, the future design of rain garden facilities should be performed by considering a microorganism appropriate to the properties of the influent pollutants, determining appropriate water content, nutrient content and soil type, and choosing plants that contribute to microbial growth. [ABSTRACT FROM AUTHOR]

Heavy metal and sediments transported from the urban catchment are the prime interest among researchers these days due to its toxic behaviour and hazardous effect on the animals, plants and human. The inflow from urban catchments and outflow from the Low impact development technologies (LID) were evaluated using different types of indices. Indices like f d , f p and K d showed that heavy metals like Pb, Cd and Ni were dominantly observed in the dissolved form. These metals possess higher threat to the water bodies receiving urban runoff without any treatments. The state of heavy metal was highly dependent on the particle size which was directly affected by the TSS EMC in urban area. The indices like f d , f p and K d were good enough to understand the behaviour, nature and state of metal in urban inflow and outflow from the system. On the other hand, calculated MPI and PERI indices showed that runoff from urban areas without any treatment bare very strong risk to the environment. LID technologies were found to be the better option in reducing the risk of urban areas to the receiving water bodies. These indices could be valuable for the decision making before the selection of applicable LID types, plants and filter media. Furthermore, indices like these can be devised to measure the impact of LID system to the environment as well as the decision making tool before discharge of outflow to the nearby streams. [ABSTRACT FROM AUTHOR]

In this study, seven different stormwater nature-based solution (NBS) was investigated to identify the relationship of bacterial community to the pollutant removal performance of stormwater NBS. Based on this study, Proteobacteria was found to be the most dominant bacteria for all stormwater NBS and IS followed by Acidobacteria and Actinobacteria. Acidobacteria , Actinobacteria , Chloroflexi , Gemmatimonadetes , WS3 , and AF234118_p were found to have high positive correlation to most pollutant removal efficiency of different stormwater NBS (r-value: 0.62 to 0.68). Using Proteobacteria and Acidobacteria count in NBS, equations predicting pollutant removal performance were developed. The equations developed in this study is useful in minimizing the cost for stormevent monitoring to identify the pollutant removal performance of NBS. • Generally, stormwater collected from roads have higher pollutant concentration compared to parking lot, combined road and parking lot and roof deck. • Proteobacteria was found to be the most dominant microorganism for all stormwater NBS and original soil. • Using Proteobacteria and Acidobacteria count in stormwater NBS, pollutant removal performance may be predicted. [ABSTRACT FROM AUTHOR]

Bacteria serve as important components of a constructed wetland (CW) system. Various bacterial communities aid in pollutant removal; however, environmental conditions and other external variables can greatly affect their performance and diversity. In this study, four constructed wetlands treating secondary livestock wastewater (LCW), agricultural runoff (ACW1 and ACW2) and urban stormwater (HCW) were investigated to evaluate the relationship between the inflow pollutants and the bacterial community. Based on the findings, the 20 dominant bacterial species in water samples collected from the livestock area (LCW) constituted 98.5% to 99.7% the total bacterial population. In the case of agricultural areas (ACW1 and ACW2), the 20 most abundant bacterial species constituted 99.7% to 99.8% of the total bacterial population. Similarly, the 20 dominant bacterial species found in the soil samples from livestock and agricultural areas made up 97.2% to 98.7% and 99.1% to 99.6% of the total bacterial population, respectively. Generally, the diversity of bacteria in soil was higher compared to water. It is important to establish a target bacterial habitat when creating CW for optimized ecological functions. • Proteobacteria was the most dominant species found in the soil and water samples. • Considering bacterial habitat, soil is more stable compared to water. • Target bacterial habitat should be considered in designing constructed wetlands. [ABSTRACT FROM AUTHOR]

The nitrogen changes and the nitrogen mass balance in a free water surface flow constructed wetland (CW) using the four-year monitoring data from 2008 to 2012 were estimated. The CW was composed of six cells in series that include the first settling basin (Cell 1), aeration pond (Cell 2), deep marsh (Cell 3), shallow marsh (Cell 4), deep marsh (Cell 5) and final settling basin (Cell 6). Analysis revealed that the NH + 4 -N concentration decreased because of ammonification which was then followed by nitrification. The NO − 2 -N and NO − 2 -N were also further reduced by means of microbial activities and plant uptake during photosynthesis. The average nitrogen concentration at the influent was 37,819 kg/year and approximately 45% of that amount exited the CW in the effluent. The denitrification amounted to 34% of the net nitrogen input, whereas the accretion of sediment was only 7%. The biomass uptake of plants was able to retain only 1% of total nitrogen load. In order to improve the nutrient removal by plant uptake, plant coverage in four cells (i.e., Cells 1, 3, 4 and 5) could be increased. [ABSTRACT FROM AUTHOR]

Abstract: For decades, the measurement of heat generated during sonication – the calorimetric method – has been considered to represent the energy efficiency of ultrasonic reactors for useful chemical reactions. In this study, a modified calorimetric energy method using cavitating and non-cavitating solutions, referred to as cavitation energy method, has been developed and compared with conventional calorimetric method for the removal of an organic pollutant, bisphenol-A, in aqueous solutions under various experimental conditions. As the liquid height/volume was increased, cavitation yield for the degradation and mineralization of BPA significantly increased at 36kHz and 262kHz. Higher cavitation yields were obtained for both degradation and mineralization at 262kHz compared to 36kHz. It was found that the cavitation energy had a better correlation with the degradation and mineralization of BPA compared to the calorimetric energy. The enhancement observed at higher liquid height has been suggested to be due to the establishment of a standing wave field. The cavitation energy method seems to be useful to design the sonochemical reactors for the removal aqueous pollutants. [Copyright &y& Elsevier]