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Helical piles can be classified as partial displacement piles in terms of moderate advancement rate. However, its installation effect on surrounding soil is unclear. This study presented four field tests on the installation of helical piles with various dimensions in silty clay. The radial earth pressure and excess pore water pressure were measured during the installation processes. The installation effect of helical pile embedded in silty clay was comprehensively discussed and evaluated from multiple dimensions of time and space, based on the cavity expansion method (CEM) and Randolph and Wroth's elastic–plastic method verified by field data. The research reveals that as the length of the helical pile increases by 1.0 time, the maximum variations in radial earth pressure and pore water pressure by a remarkable 25.0 times and 7.8 times, respectively. Additionally, when the shaft diameter of the helical pile expands by 20%, the maximum alterations in radial earth pressure and pore water pressure swell by approximately 18.6 and 5.7%, respectively. Comparing the radial earth pressure at various embedment depths at the same penetration stage, it is found that the radial earth pressure induced by helices is slightly greater than that induced by pile shaft. The estimated radial earth pressure and pore water pressure agree with the measured maximum data, and the pore water pressure generated by the installation of helical pile completely dissipates after 10–12 days of installation in this work. [ABSTRACT FROM AUTHOR]

The high concentration of chlorophyll a (Chl-a) and pollutants in estuaries has led to the deterioration of marine environmental quality and a reduction in the sustainability and safety of marine ecosystems. This study analyzed the distribution characteristics of Chl-a and pollutants in the Liugu Estuary (LE) based on field survey data. By incorporating environmental factors, the water's nutritional status and nutrient limitations were evaluated. The results indicated that there were variations in the concentration range of Chl-a and pollutants between flood and non-flood seasons in the LE, with nitrogen identified as the main limiting nutrient. The correlation indicated that Chl-a and nutrient levels in the LE were influenced by a complex interplay of multiple factors. River inputs with higher pollution levels increased concentrations and reduced DO levels, limiting the rise in Chl-a concentration and the uptake of nutrients by phytoplankton. The findings of this study could provide essential information for an in-depth examination of the eutrophication characteristics of the LE and offer a scientific foundation for the restoration and management of the estuary's ecological environment. [ABSTRACT FROM AUTHOR]

Ni-ethylenediaminetetraacetic acid (Ni-EDTA) poses serious threats to the ecological environment and human health, due to its acute toxicity and low biodegradability. The decomplexation efficiency of Ni-EDTA through the conventional Fenton process has been constrained to pH; thus, other appropriate approaches are required to destroy the stable chelate structure at a neutral pH. In this study, the effect of operating parameters such as the pH, Fe2+ concentration, particle electrode dosage, current density, and coexisting ions was studied. The results revealed that the 3D-EF system owned advantages for the removal of Ni-EDTA in the broadening of the pH application window. The Ni-EDTA removal efficiency in the 3D-EF system reached 84.89% after 120 min at a pH of 7. In addition, the presence of coexisting ions slightly affected the decomplexation efficiency of Ni-EDTA. [ABSTRACT FROM AUTHOR]

The objective of this study was to prepare biochar/clay composite particle (BCCP) as carrier to immobilize Ochrobactrum sp. to degrade ammonia nitrogen (NH4+-N), and the effects of calcined program and immobilizing material were investigated. Results reflected that the parameters were as follows: calcined temperature 400°C, heating rate 20°C min–1, and holding time 2 h, and the adsorption capacity could reach 0.492 mg g–1. Sodium alginate/polyvinyl alcohol, as embedding material, jointed with NH4+-N adsorption process and then degraded by Ochrobactrum sp. with 79.39% degradation efficiency at 168 h. Immobilizing Ochrobactrum sp. could protect strain from high salt concentration to achieve the exceeding degradation efficiency than free bacteria, but could not block the impact of low temperature. [ABSTRACT FROM AUTHOR]

Harmful algal blooms (HABs) have occurred frequently in coastal waters of China, imposing negative effects on the marine ecological environment. A dataset of HABs and terrestrial runoff was collected and analyzed in this study, and factors responsible for HABs were further explored. Frequency and expansion of HABs peaked between 2001 and 2007, and although they have declined slightly since then, they have remained quite high. Frequency and accumulative area of HABs peaked in 2004–2005, and most occurred from April to August during these years. HABs occurred frequently in the Changjiang (Yangtze River) estuary, and Prorocentrum donghaiense, Noctiluca scientillans, Karenia mikimotoi, and Skeletonema costatum were the main algal species. The increases of eutrophication, the abnormal sea surface temperature caused by climate and ocean currents, and the species invasion caused by the discharge of ballast water may be important factors for the long-term outbreak of HABs in the Chinese coastal waters. These findings provide a better understanding of HABs in China, which will be helpful to further prevention and control. [ABSTRACT FROM AUTHOR]

The mining areas have faced severe pollution by caustic metals. In this study, heavy metals (Cu, Zn, Cr, Cd, Pb and Ni) in the soil of an extremely large iron mine pit from Ningwu-Luohe metallogenic belt, one of the seven iron ore areas in China was characterized. SiO2 was predominant soil mineral composition as 57.0 ± 1.3 %, followed by considerable Al2O3 (23.1 ± 2.5 %) and Fe2O3 (8.58 ± 1.2 %). Cu, Zn, Cr, Cd, Pb and Ni had the range of 7.62–237, 97.8–313, 1.73–43.8, 0.119–0.512, 5.13–44.7 and 7.87–23.9 mg/kg, respectively, wherein, Cu, Zn, Cr and Pb were likely to have relatively low concentration in the soil from the boom of mining pit. Comparatively, both Cu and Zn arose at the level of 1-fold higher than that of local background values, indicating that the soil from mining pit had been subjected to Cu and Zn accumulation. BCR (European Communities Bureau of Reference) sequential extraction analysis showed that these metals mainly existed in residual fraction, with averaged percentages of 42.0 ± 18 %, 70.3 ± 8.1 %, 76.6 ± 18 %, 30.2 ± 14 %, 52.5 ± 11 % and 61.0 ± 9.7 % for Cu, Zn, Cr, Cd, Pb and Ni, respectively. Geo-accumulation index indicates that the soil was moderately contaminated by Cu, practically uncontaminated or uncontaminated to moderately contaminated by Zn, while practically uncontaminated by Cr, Cd, Pb and Ni. There were just significant relationships between Zn and Cd and between Cd and Pb, indicating that Cd in the soil investigated possibly had at least two sources and for most of the elements the sources were different. The effects of pit depth and major soil composition on the distribution of trace metals varied depending on the element itself and its chemical forms. [ABSTRACT FROM AUTHOR]

Inland waters are considered hotspots of greenhouse gas (GHG) emissions and have been extensively researched. Static chamber (STAT) and thin boundary layer (BLE) are two commonly used methods for analyzing diffusive GHG emissions from inland waters. However, the STAT method is often disturbed by GHG bubbles; meanwhile, many kinds of headspace gas are used in the BLE method, but the differences between their diffusive GHG emission analysis results are not understood. In this study, the chamber in the STAT method was modified to combat the disturbances from GHG bubbles, and the typically used gases for the BLE method, namely, pure nitrogen, air, and filtered air, were comparatively studied. Results demonstrated that the modified chamber could effectively prevent the invasion of GHG bubbles; it increased the success rate from 67 to 90% in the field test, with no obvious impacts on the results of the GHG emission analyses. The use of air and filtered air in the BLE method yielded the lower values of GHG emissions relative to pure nitrogen, and this finding was potentially attributed to the inhibition effects of the residual GHGs and high humidity in air and filtered air on the extraction of diffusive GHGs from the surface water. This study improved the commonly used methods for diffusive GHG emission analysis, and the current findings are beneficial to the study of GHG emissions from inland waters. [ABSTRACT FROM AUTHOR]

Constructed wetlands (CWs) are natural-friendly method to eliminate the pollutants stormwater pollutants. For this study, a pilot-scale treatment system consisting of a sedimentation tank (ST) and five recirculated fill-and-drain wetlands (namely CW-1, CW-2, CW-3, CW-4 and CW-5) were constructed to treat the first-flush from the impervious road. From bottom to top, the main substrates of CWs were selected as 0 cm woodchip + 60 cm pumice for CW-1, 15 cm woodchip + 45 cm pumice for CW-2, 30 cm woodchip + 30 cm pumice CW-3, 45 cm woodchip + 15 cm pumice CW-4 and 60 cm woodchip + 0 cm pumice for CW-5. During the operational period, the reduction efficiencies of TSS, total COD, total nitrogen and total phosphorus were 89–100%, 52–100%, 31–87% and 72–100% by CW-1, 92–100%, –27% to 78%, 8–85%, 49–94% by CW-2, 89–100%, –97% to 77%, –29% to 86%, –46% to 94% by CW-3, 89–100%, –115 to 69%, –21% to 99%, 35–94% by CW-4 and 59–100%, –342%to 88%, –20% to 88%, –77% to 99% by CW-5, respectively. Overall, the reduction efficiency, except for nitrogen, declined as the amount of woodchip increased. As excepted, the employment of woodchip improved denitrification via providing with carbon sources, resulting in low NO3–N but unfavourable COD concentrations in the effluent. And the combination use of woodchip and pumice as CW-3 or CW-4 is suggested, whereas the specific amount of woodchip and pumice should be determined based on the regional environmental goal. [ABSTRACT FROM AUTHOR]

In this study the road dusts (RDs) <1,000 μm from Maanshan City, China were characterized from the prospects of size fractionated pollution by heavy metals (HMs). Particulates with size <75 μm, 75–125 μm, 125–250 μm, 250–500 μm and 500–1,000 μm averagely accounted for 35.7±11.7%, 14.6±11.0%, 25.3±12.5%, 11.6±8.8% and 12.8±12.9% of the total weight, respectively. This result implies the gravimetric percentage was overall declined with increasing granular size, following gamma distribution function (p < 0.001). It was observed that the highest contents of Zn, Ni, Pb and Cd occurred with the fine RDs < 75 μm while Cu with these < 125 μm, suggesting HMs preferred to be associated with the fine particulates. Cu, Zn, Ni, Pb, Cr and Cd were present in RDs with bulk contents of 68±30 mg/kg, 285±122 mg/kg, 23±16 mg/kg, 53±21 mg/kg, 432+297 mg/kg and 0.56±0.39 mg/kg, which resulted in geo-accumulation index (lgeo) values as -1.04, 2.35, -2.38, 0.38, 1.54 and 0.18, respectively. Hence, it can be concluded that the RDs had only been significantly polluted by Zn. Person correlation analysis suggests those HMs ubiquitously present in RDs had size-dependent sources. [ABSTRACT FROM AUTHOR]

Construction and demolition (C&D) waste generated in the process of urban development has rapidly increased in recent years around the world in large quantities without proper reuse, resulting in negative environmental impact. Adsorption experiments were carried out by using red brick, burn-free brick and concrete brick, respectively. Results indicated that the hydraulic conductivity was influenced by the waste bricks type. And phosphorus removal increased with increasing initial aqueous phosphorus concentrations and the contacting time. While it decreased with co-exist anions (such as SO42-, Cl−, NO3− and HCO3−), and no evident variation was found for the adsorption capacity of phosphorus for the three kinds of waste bricks while the solution pH ranged from 5 to 9. Thus, we can conclude that demolition waste bricks showed a great application potential as infiltration system geomedia in terms of hydraulic conductivity and phosphorus adsorption. [ABSTRACT FROM AUTHOR]

Phosphorus (P) is a vital nutrient for algal growth. Aside from soluble reactive P (SRP), organic P (OP) is used by algae via alkaline phosphatase (AP) hydrolysis, which can play an important role in supplying P. Enzymatically-hydrolysable OP (EHP) can potentially be used as an indicator of bioavailability of P other than SRP in natural waters. We investigated the ecological significance of alkaline phosphatase activity (APA), EHP concentration and P turnover time in the inflowing rivers of Lake Taihu (Taihu) during three hydrologic periods. Results indicated high SRP concentration and low SRP demand by algal suppressed APA in the inflowing rivers, the highest proportion of OP mineralization rate (v) to the maximum reaction velocity of AP (Vmax) is only 14.7%. P turnover time of the inflowing rivers was generally from 3 to 7 days and in exceptional cases, it could exceed 10 days. The high EHP reserve and the sufficient AP for OP mineralization render the rivers a significant source of utilizable OP, further exacerbating eutrophication of Taihu. [ABSTRACT FROM AUTHOR]

Road-deposited sediment (RDS) has been identified as both the source and sink of various pollutants. In this study, the highway-deposited sediment (HDS) in Spring, Summer, Autumn and Winter was characterized. On average, the mass proportions of particles with the size of 830–4750 μm, 500–830 μm, 250–500 μm, 150–250 μm, 63–150 μm and < 63 μm were 23.6 ± 8.6%, 16.9 ± 3.4%, 28.4 ± 3.5%, 10.0 ± 4.3%, 15.7 ± 5.8% and 5.3 ± 2.0%, respectively, wherein the HDS of 63–830 μm accounted for 71% of the total mass load. It was observed that the particle size distribution of HDS could be described using the gamma distribution function based on gravimetric and cumulative basis (R2 (determination coefficient) = 0.9960–0.9995). The bulk pollutant contents of HDS showed seasonal variation with the mean of COD (chemical oxygen demand), nitrogen, phosphorus, Zn (zinc), Pb (lead) and Cd (cadmium) as 57 g/kg, 839 mg/kg, 97 mg/kg, 627 mg/kg, 110 mg/kg and 1.00 mg/kg and the highest COD of 83 g/kg in Autumn, nitrogen 1164 mg/kg Autumn, phosphorus 133 mg/kg Winter, Zn 801 mg/kg Summer, Pb 133 mg/kg Spring and the highest Cd of 1.36 mg/kg in Summer, respectively. The contents of Zn, Pb and Cd in HDS were significantly above their local soil background values. Moreover, the size fractional pollutant contents overall increased as particles' size increased. Averagely, 40–52% pollutant loads were associated with the particles < 250 μm, which can be moved easily by runoff. This study suggests that the behaviors of HDS different from city RDS should be considered as nonpoint source pollution control is performed. [ABSTRACT FROM AUTHOR]

For the first time rhenium-containing biimidazoles have been structurally reported with two triphenylethylene units following chiral and cis–trans transformations simultaneously. Crystal structures show that the biimidazole ligand exhibits an (M)-trans-(P) configuration, whereas the (M)-cis-(M) mode was observed in the rhenium complex, showing cis–trans configurations between biimidazoles and the relative chiral isomers among adjacent triphenylvinylimidazole units. Furthermore, aiming to verify the association rule between spectral behaviours and orientational changes, fluorescence titration experiments were performed for full comparison where the detection performance for explosives in an aqueous phase depends on the alternation of the molecular structure, including the introduction of two alkyl chains and fac-[Re(CO)3Cl]. In addition, computational studies on molecular conformations with different torsion angles for related compounds were carried out. [ABSTRACT FROM AUTHOR]

In order to control nitrogen (N) pollution of Lake Taihu, China, we studied the spatial and temporal distribution characteristics of inorganic N in inflowing rivers polluted by industry, agriculture, and domestic sewage during low, moderate, and high flow periods. The results showed that dissolved total nitrogen (DTN) was the main fraction of total nitrogen (TN) input from these rivers. Inflowing rivers had distinct impacts on TN, DTN, ammonium N (NH4+), and nitrate N (NO3−) concentrations of Lake Taihu during the low flow period. Particulate nitrogen (PN) had an impact on Lake Taihu during the three flow periods and all the three types of rivers would increase PN concentration in the lake. Rivers polluted by agriculture had the greatest impact on Lake Taihu's TN, DTN, NO3−, and dissolved inorganic N (DIN) concentrations, while rivers polluted by industry had the greatest impact on NH4+ concentration. Therefore, agriculture and industry should be key targets for nutrient reductions. The in-lake N concentrations were higher than those of inflowing rivers during moderate and high flow periods. [ABSTRACT FROM AUTHOR]

A new class of 2D fewer-layer π-conjugated conductive metal–organic nanosheets was developed via the Langmuir–Blodgett method, exhibiting ultrahigh mass activity (64.63 A mg−1, 1.7 V vs. RHE) and stability for electrochemical oxygen evolution reactions (OER). [ABSTRACT FROM AUTHOR]

Injury of hippocampal neurons in status epilepticus (SE) SD rats kindled by pentylenetetrazol (PTZ) were studied, and the changes of apoptosis neurons, protein expression of Bad and Bcl-2 alone and combined application of phosphatidyl inositol 3-kinase (PI3K) inhibitor LY294002 and recombinant human erythropoietin (rHuEpo) were evaluated for the possible mechanisms of rHuEpo. The SE rats kindled by the PTZ were randomly divided into normal control group [normal saline (NS)], model group (PTZ + NS), rHuEpo treated group (PTZ + rHuEpo), LY294002 treated group (PTZ + LY294002 + rHuEpo) and LY294002 control group (rHuEpo + PTZ + DMSO). Apoptosis of hippocampal neurons was detected by TUNEL method; expression of phosphorylation protein kinase B (p-PKB/p-Akt), Bcl-2 and Bad were detected by immunohistochemistry; the expression of Bcl-2 mRNA, Bad mRNA in hippocampal neurons of rats were detected through reverse transcription polymerase chain reaction (RT-PCR); the expression of Akt, p-Akt and Bcl-2, Bad protein in hippocampal neurons of rats were detected by western blotting. The amount of apoptotic neurons was less in the rHuEpo treated group and the LY294002 control group than in the LY294002 treated group (P<0.05). The expression of p-Akt protein and Bcl-2 protein increased while the Bad protein decreased significantly in the rHuEpo treated group and the LY294002 control group compared with the LY294002 treated group (P<0.05). The expression of Bad protein and Bad mRNA in hippocampus increased while the p-Akt, Bcl-2, Bcl-2 mRNA decreased significantly in the LY294002 treated group compared with the rHuEpo treated group (P<0.05). The PI3K/Akt signaling pathway is one of the pathways of rHuEpo neuroprotective effects and was confirmed from both the of positive and negative aspects. rHuEpo regulates the expression of mitochondrial apoptotic pathway related factors Bad and Bcl-2 to inhibit apoptosis and promotes neuronal survival. [ABSTRACT FROM AUTHOR]

Runoff pollution have become a serious issue in terms of water pollution in porous areas, especially in urban backfilled soil. The transport and distribution of runoff water and nutrients in the surface runoff and the subsurface runoff of backfilled soil runoff systems are determined using simulated rainfall and the results indicate that the flow patterns of runoff are different from those of surface runoff and subsurface runoff. The rate of surface runoff flow increases in the beginning and reaches a stable state with a delay of 10 min to rainfall, while the flow rate of subsurface runoff is consistent during the whole runoff period. Most of the pollutants (90% of total suspended solids, 88% of total phosphorus, and 78% of total nitrogen) are carried in the surface runoff, which directly results in polluting the surface‐receiving water. The results of the present study will provide information related to the management of runoff pollution in the backfilled soil runoff system. [ABSTRACT FROM AUTHOR]

Stormwater pollution in redeveloped soils mixed with construction wastes imposes a serious impact to receiving waters. The transport and distribution of rainfall water and nutrients in the surface-flow and subsurface-flow (including side-flow and down-flow) of bare redeveloped soil runoff system were determined. Results indicated that the flow patterns and pollutants transport of surface-flow were different from those in subsurface-flow. The flowrate of surface-flow increased at the beginning and reached to a stable state, and then disappeared immediately after the rainfall stopped. While the flow rate of subsurface-flow was persisted and decreased gradually artery the rainfall. Most of the pollutants were carried in the surface-flow, which directly results in polluting the surface-receiving waters. And the pollutants distribution percent in side-flow was higher than that in down-flow. Results obtained in this study will provide information for the management of stormwater pollution in the bare redeveloped soil mixed with construction wastes. [ABSTRACT FROM AUTHOR]

Surface-deposited sediment in urban areas is an essential environmental medium for assessing nutrient contamination. The total nitrogen (TN) and total phosphorus (TP) pollution associated with surface-deposited sediments can be transported into urban water bodies by runoff and can cause eutrophication of those water bodies. By analyzing the samples collected on roof surfaces and road surfaces, this study provides a comparison of the differences in TN and TP pollution loading in sediments on these two different impervious surface materials. Also, an assessment of the ecological risk of nutrients in surface-deposited sediments with respect to grain size fraction was performed. The results indicate that the TN and TP pollution loading in both road-deposited sediments and roof-deposited sediments indicated an asymmetric “W” trend along with grain size fraction, and both road-deposited sediments and roof-deposited sediments had the highest TN and TP pollution contribution when the particle size is between 250 and 500 μm. TN in roof-deposited sediments has high ecological risk when the particle size is less than 250 μm. These findings help to provide guidance for the management of surface-deposited sediment pollution. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the effects of carotid artery angioplasty and stenting (CAAS) on patients who were diagnosed with ocular ischemic syndrome (OIS). Methods: Sixty-four eyes of 64 OIS patients with ipsilateral internal carotid artery stenosis ≥70% were included in the study. The study eyes were divided into two groups according to the presence of iris neovascularization: NVI-absent group and NVI-present group, with 32 eyes, respectively. All patients received ocular treatment modality according to the presence of non-perfusion area (pan-retinal photocoagulation) and intraocular pressure (medical treatment included timolol maleate eye drops combined with brinzolamide eye drop; trabeculectomy and cyclophotocoagulation). All patients went through CAAS surgery for treatment of internal carotid artery stenosis. Best-corrected visual acuity (BCVA); intraocular pressure (IOP), slit lamp examination, iris fluorescence angiography, fundus fluorescein angiography and color Doppler ultrasound of the internal carotid artery (ICA), ophthalmic artery (OA), central retinal artery (CRA), and short posterior ciliary arteries (PCA) were performed pre-operatively and 1 month, 3 months, 6 months, and 12 months post-operatively. Results: There was no significant BCVA change postoperatively in the NVI-absent group, while postoperative BCVA in the INV-present group decreased significantly. There was no significant BCVA difference at pre-operative and 1month post-operative follow-up between the two groups. However, post-operative BCVA of NVI-present group starting from 3-months follow-up was significantly worse than NVI-absent group. Arm-retinal artery circulation time and arteriovenous circulation time decreased significantly in NVI-absent group, while showed no statistical difference in NVI-present group during the 12-months follow-up. Postoperative peak systolic velocity (PSV) of the ophthalmic artery, the central retinal artery, and short posterior ciliary artery showed significant increases at 1 month, 3 months, 6 months and 12 months follow-up in both groups. Conclusion: CAAS can greatly improve ocular blood in OIS patients with and without iris neovascularization. However, CAAS improved BCVA only in patients without iris neovascularization. [ABSTRACT FROM AUTHOR]

Surface-deposited sediment in urban area is an essential environmental medium for assessing heavy metal contamination. A total of 10 sampling trips were conducted to collect road-deposited and roof-deposited sediments for the comparison of nickel (Ni), copper (Cu), cadmium (Cd), lead (Pb), zinc (Zn), and chromium (Cr) contamination characteristics. Results indicated that roof sediment appeared to have a finer size distribution than road sediments. Roof sediment indicated higher metal concentration and lower surface loading than road sediment. The impact of particle size on heavy metal contamination was quantified by using the developed pioneering term of finer particle effect factor; it differed according to surface types and grain size fraction. Particles in individual grain size fraction showed different contribution to the surface loading for bulk sediments. No consistent trend was found for the grain size fraction loading along with grain size for the studied heavy metals for road sediments. In contrast, an asymmetric 'W' trend was observed for the roof sediments, and it had the following results: Fraction of <63 and 250-500 μm showed higher loading, while fraction of 90-125 and >850 μm indicated the smaller loading. Findings above facilitated the appropriate management practice selection for the treatment of surface-deposited sediments. [ABSTRACT FROM AUTHOR]

Activated sludge samples collected from 20 full-scale wastewater treatment plants were investigated to determine the effects of floc size ( D50) on sludge settling characteristics. Results indicated that no simple and apparent relationship was found between D50 and sludge volume indices ( SVIs) because of the complicated affecting mechanism of various parameters. Effects of D50 on the Vesilind settling model parameters were evaluated. Results indicated that no apparent relationship was found between D50 and V0. However, in the case of activated sludge with higher V0 (>5 m/h), there was a power function type correlation ( V0 = 67.368·D50−0.4298, R2 = 0.5304) between V0 and D50. Furthermore, the parameter k decreased with increasing D50 through the relationship of k = 11.37· D50−0.5273 ( R2 = 0.5593), except for samples with D50 < 100 μm and k < 1.0 m3/kg. V0 and k sludge were negatively correlated with sludge concentration because higher sludge concentrations contributed more resistance to settling velocities and their change rates. Results obtained in this study could provide scientific information for effective separation of activated sludge. [ABSTRACT FROM AUTHOR]

This study was carried out to identify the filter performance of fibre filter module treating high-turbidity water at extremely high filtration rates (1000–2500 m/day). The effects of filter aid chemical (polyaluminium chloride (PAC)), filtration rate and particles size on filter performance were investigated. It was found that PAC was a crucial factor influencing the separation process. Even though the optimum PAC dose for the raw water with turbidity of 50 nephelometric turbidity units (NTU) was 0.5 mg/L, the turbidity removal efficiencies were similar as the raw water turbidity was no more than 50 NTU. As expected, the filter performance was negatively affected by the increased filtration rate. However, the turbidity removal efficiency at an extremely high filtration rate still was amazing and attractive (∼80% at 2500 m/day). Moreover, theD50and uniformity coefficient of the particles in raw water were not the factors greatly affecting the filter performance. The empirical model for the filter processes of granular filters did not work; therefore, an empirical model towards fibre filters at a high flow rate was suggested, which can be used to predict the treatment performance. [ABSTRACT FROM AUTHOR]

A design methodology was proposed for the hydrocyclone used for solids separation from runoff. The design approach was validated by performing experiments on anin situhydrocyclone with a diameter of 7.5 cm. The performance of the hydrocyclone was evaluated based on monitoring work, with the results indicating that the observed average pressure inside the collection pipe was proportional to the rainfall intensity. When the respective average observed pressure was 1.5 and 5.0 m water head, the volume fraction of underflow was estimated as 16 and 12%, respectively. The solids separation efficiency was proportional to the pressure, and it was in the range of 20–90% ,while the pressure ranged from 0.5 to 9 m water head. For the hydrocyclone in the test bed, the operation energy was directly provided by the pressure generated inside the collection pipe. In the case of the potential energy being unavailable, a pump can be applied to support the required energy. While the respective flow rates were 0.8, 2.4, and 3.6 m3/h, the total required energy was 1.7, 6.7, and 10.7 m water head, respectively. [ABSTRACT FROM PUBLISHER]

In this research, the mobilization and distribution of lead originating in roof dust and wet deposition were investigated within a roof dust-rooftop-runoff system. The results indicated that lead from roof dust and wet deposition showed different transport dynamics in runoff system and that this process was significantly influenced by the rainfall intensity. Lead present in the roof dust could be easily washed off into the runoff, and nearly 60 % of the total lead content was present in particulate form. Most of the lead from the roof dust was transported during the late period of rainfall; however, the lead concentration was higher for several minutes at the rainfall beginning. Even though some of the lead from wet deposition, simulated with a standard isotope substance, was adsorbed onto adhered roof dust and/or retained on rooftop in runoff system, most of it (50-82 %) remained as dissolved lead in the runoff for rainfall events of varying intensity. Regarding the distribution of lead in the runoff system, the results indicated that it could be carried in the runoff in dissolved and particulate form, be adsorbed to adhered roof dust, or remain on the rooftop because of adsorption to the roof material. Lead from the different sources showed different distribution patterns that were also related to the rainfall intensity. Higher rainfall intensity resulted in a higher proportion of lead in the runoff and a lower proportion of lead remaining on the rooftop. [ABSTRACT FROM AUTHOR]

The FeO nanofibers were prepared by electrospinning method. The phase composition and morphology were analyzed by XRD and FE-SEM. The results indicated that the pure FeO nanofibers were obtained and exhibited evident shape anisotropy. The magnetic study via VSM showed that the FeO nanofibers possessed ferrimagnetic properties. The saturation magnetization was around 58.4 emu/g and the coercivity was approximate 186.7 Oe. In addition, the electromagnetic loss properties were detailed investigated by network analyzer. The dispersion relaxation phenomenon was observed in the frequency range of 2-18 GHz. The dielectric loss was caused by the interface polarization and the magnetic loss was owing to the exchange resonance. The as-prepared FeO nanofibers showed excellent electromagnetic loss properties and could be potentially applied as the lightweight microwave absorption materials. [ABSTRACT FROM AUTHOR]

The material composition of road-deposited sediments (RDS) collected from five different sites was measured, and its effects on the pollution of selected heavy metals (zinc, chromium, and lead) were revealed. Results indicated that RDS mainly consisted of quartz, amorphous materials, and inorganic minerals including silicates and carbonates. Due to the different material composition with solids in different size ranges, the unit specific surface area load of selected heavy metals indicated an increasing trend with increasing solid size. The influence of material composition of RDS on heavy metal pollution was further investigated. It was found that the presence of quartz indicated a negative effect on the pollution of zinc, chromium, and lead due to the electrically neutral characteristic of quartz. The amorphous content was positively related to the selected metal pollution because most of amorphous materials originated from traffic-related sources. In addition, the metal pollution was proportional to the content of inorganic minerals (silicates, carbonates) and some clay minerals due to their high surface area and usually negatively charged surface. Taken together, the material composition of RDS indicated a crucial influence on heavy metal pollution. [ABSTRACT FROM AUTHOR]

A new mathematical model for predicting the contact efficiency of a single collector in the treatment of turbid water is presented in this study. The removal mechanisms applied were interception, diffusion, and sedimentation. In order to obtain the model for the single-collector efficiency, the effect of the density current caused by turbidity and differences in temperature was considered and the impact of multiple-size particles was also included when calculating the respective mechanisms. The sticking coefficient was also calculated, including the effect of the van der Waals attraction energy and electrical double layer forces. The result of the modeling indicated that the predicted efficiency using the developed equation showed good agreement with the experimental values over a wide range of parameters and the increases and decreases in the model performance were simulated very well. The quality of the data was analyzed and this indicated that the experimental work and the developed model showed fairly good agreement. [ABSTRACT FROM AUTHOR]

Pollution of hazardous elements in roof runoff has been a potential danger to aquatic ecosystem as documented in previous studies. In this study, concentrations of lead (Pb), zinc (Zn), arsenic (As), and cadmium (Cd) in roof runoff were measured for short-term rainfall events. The concentrations of the selected elements varied to a high degree during the rainfall period, and the well-known first-flush phenomenon was not observed due to the short-term rainfall patterns. Based on event mean concentrations (EMCs) and fluxes, the elemental pollution may be ranked as Zn >> Pb > As > Cd. The average levels of Pb and Zn exceeded the fourth class value and fifth class value of the environmental quality standards for surface water in China. The relative high pollution could be caused by atmospheric deposition and the erosion of crust steel appurtenance installed above the rooftop. Furthermore, elements in particulate form dominated the roof runoff pollution, and the ratios of elements in particulate form to total amounts were 0.6 (As), 0.9 (Pb), 0.7 (Cd), and 0.5 (Zn). This study cleared the pollution characteristics of hazardous elements in short-term storm water roof runoff; it was useful for the selection of best management practices. [ABSTRACT FROM PUBLISHER]

A hydrocyclone using natural water head provided by bridge was operated for the treatment of stormwater runoff. The hydrocyclone was automatically controlled using electronic valve which is connected to a pressure meter. Normally the hydrocyclone was open during dry days, but it was closed after the capture of the first flush. The results indicated that the average pressure and the flow rate were directly affected by the rainfall intensity. The pressure head was more than 2 m when the rainfall intensity was above 5 mm·h −1. The percentage volume of underflow with high solids concentration decreased as the pressure and flow rate increased, but the percentage volume of overflow with almost no solids showed the opposite behavior. The total suspended solids (TSS) concentration ratio between the overflow and inflow (TSS over/TSS in) decreased as a function of the operational pressure, while the corresponding ratio of underflow to inflow (TSS under/TSS in) increased. The TSS separation efficiency was evaluated based on a mass balance. It ranged from 25% to 99% with the pressure head ranging from 1.4 to 9.7 m, and it was proportional to pressure and flow rate. Normally, the efficiency was more than 50% when the pressure was higher than 2 m. The analysis of the water budget indicated that around 13% of the total runoff was captured by the hydrocyclone as a first flush, and this runoff was separated as underflow and overflow with the respective percentage volumes of 29% and 71%. The pollutants budget was also examined based on a mass balance. The results showed that the percentage of TSS, chemical oxygen demand (COD), total nitrogen (TN), and total phosphorus (TP) in underflow were 73%, 59%, 7.6%, and 49%, respectively. Thus, it can be concluded that the hydrocyclone worked well. It separated the first flush as solids-concentrated underflow and solids-absent overflow, and effectively reduced the runoff volume needing further treatment. Finally, four types of optional post treatment design are presented and compared. [ABSTRACT FROM AUTHOR]

Performance of a synthetic-fibre mat was investigated for the treatment of high-turbidity runoff. The impact of different operating parameters, such as hydraulics (flow rate and exchange rate), density current due to temperature and turbidity differences, mat conditions (thickness and number) and particle size were studied. The experimental results showed that increasing the mat thickness and number enhanced turbidity removal. The density current showed significant inverse effect on mat performance. Turbidity removal decreased with the increasing flow rate and exchange rate. Particle size also indicated an influence on removal efficiency. Predictive correlations for turbidity removal efficiency and mat design were established using dimensionless groups based on the experiment. The simulation results indicated that the predicted values correlated with the experimental ones significantly. Finally, the application design process was demonstrated. [ABSTRACT FROM PUBLISHER]

Many best management practices have been developed and implemented to treat the nonpoint source pollution of the aquatic environment in Korea's four major river basins. The performance and cost of these facilities were evaluated and compared using broad categories, including grassed swales, constructed wetlands, vegetated filter strips, hydrodynamic separators, media filters, and infiltration trenches, based on the monitoring and maintenance work undertaken between 2005 and 2012. Constructed wetlands, media filters, and infiltration trenches generally performed better in removing pollutants than other types of facilities, while media filters were the most expensive factor in terms of construction and operational costs. In addition, constructed wetlands incurred the least operational cost, as well as helping to control the quantity of runoff. This illustrates that a high cost facility does not necessarily give a better performance. A slightly more expensive facility, such as wetland, could prove to be a reasonably effective treatment. The selection of the most appropriate treatment for stormwater runoff should be based on an overall analysis of performance and cost. [ABSTRACT FROM AUTHOR]

A stormwater wetland treating non-point source pollution (NPS) from a 64 ha agricultural watershed was monitored over a period of five months. The results indicated that pH and dissolved oxygen (DO) were increased in the wetland due to the algal growth. The highest total suspended solids (TSS) concentration was observed in the aeration pond due to the resuspension of solids, decreased in the wetland. The respective decreases in total nitrogen (TN) and total kjeldahl nitrogen (TKN) were 15.9% and 28.7% on passing through the wetland. The nitrate and ammonia were increased by 45.4% and decreased by 79.9%, respectively. These variations provided strong evidence for the existence of nitrification. The total phosphorus (TP) and phosphate had respective reductions of 52.3% and 58.2% over the wetland. The total chemical oxygen demand (TCOD) and soluble chemical oxygen demand (SCOD) were also decreased. Generally, the TN, TP and phosphate removal efficiencies were positive. These positive removal efficiencies were mainly due to microbial activities, uptake by plants, and chemical precipitation at high pH. Negative removal efficiencies can be caused by continuous rainfall activities, with short antecedent dry days (ADDs) and unstable hydraulic conditions, some other biogeochemical transformations and algal growth also being important parameters. [ABSTRACT FROM AUTHOR]

In order to investigate the tolerance of an anoxic-oxic (A/O) process for the changing of refractory organics in electroplating wastewater, optimize the technological parameters, and reveal the microbial characteristics, a pilot-scale A/O process was carried out and the microbial community composition was analyzed by high-throughput sequencing. The results indicated that a better tolerance was achieved for sodium dodecyl benzene sulfonate, and the removal efficiencies of organic matter, ammonia nitrogen (NH4+-N), and total nitrogen (TN) were 82.87%, 66.47%, and 53.28% with the optimum hydraulic retention time (HRT), internal circulation and dissolved oxygen (DO) was 12 h, 200% and 2–3 mg/L, respectively. Additionally, high-throughput sequencing results demonstrated that Proteobacteria and Bacteroidetes were the dominant bacteria phylum, and the diversity of the microbial community in the stable-state period was richer than that in the start-up period. [ABSTRACT FROM AUTHOR]

In view of the expansion and directional change mechanisms of Yangtze River water diluted with sea water in the shelf region (also known as Changjiang diluted water [CDW]) during summer and autumn, a three-dimensional hydrodynamic model of the Yangtze River Estuary (YRE) and its adjacent waters was established based on the Finite Volume Community Ocean Model (FVCOM). Compared with the measured data, the model accurately simulates the hydrodynamic characteristics of the YRE. On that basis, the influence of the expansion patterns of the CDW in both summer and autumn was studied. It was found that, in 2019, the CDW expanded to the northeast in the summer and to the southeast in the autumn, and that the route of the CDW is mainly controlled by the wind, not the runoff. Current seasonal winds also change the transportation route of the CDW by affecting its hydrodynamic field. Typhoons are frequent in both summer and autumn, causing abnormalities in both the transportation route and expansion of the CDW. During a typhoon, a large amount of the CDW is transported in a continuous and abnormal manner, accelerating the path turning of the CDW. This paper enhances the existing theoretical research of the CDW and provides a reference with respect to the expansion of diluted water all over the world. [ABSTRACT FROM AUTHOR]

Increasing attention has been given to the treatment of livestock and poultry wastewater because of its high ammonium nitrogen (NH4+-N) content and low carbon/nitrogen ratio (C/N). Ceramic filter medium (CFM) and dewatered aluminum sludge (DAS), which are products from cast-off materials, are used as small-scale combined biological filters (CFM-DAS) for wastewater treatment. The high and stale removal efficiency of chemical oxygen demand (COD), NH4+-N, and total nitrogen (TN) in the DAS filter indicate that DAS plays a major role in pollutant removal. Although significant differences are found between the composition of nitrifying bacteria in CFM and DAS, the structures of nitrifying communities are evenly distributed in each layer of CFM or DAS irrespective of the running time. Microbial compositions are attributed to the comprehensive effect of various environmental factors such as pH and TN at effluents. In the DAS, Nitrosospira shows significant negative correlation with the concentrations of NH4+-N in effluents, whereas it has positive correlation with NO3−-N, and Nitrososphaera has a significant negative correlation with NO3−-N in effluents. Pearson correlation test reveals that certain genera may be used in estimating or predicting NH4+-N consumption and NO3−-N accumulation in CFM-DAS for treating sewage with a high NH4+-N content. [ABSTRACT FROM AUTHOR]