The cross plots of diagnostic ratios also confirmed coal and wood combustion and traffic emissions in the region.Stormwater sediments of various sizes and densities are recognised as one of the most important stormwater quality parameters that can be conventionally controlled by settling in detention ponds. The bottom grid structure (BGS) is an innovative concept proposed in this study to enhance removal of stormwater sediments entering ponds and reduce sediment resuspension. This concept was studied in a hydraulic scale model with the objective of elucidating the effects of the BGS geometry on stormwater sediment trapping. Towards this end, the BGS cell size and depth, and the cell cross-wall angle were varied for a range of flow rates, and the sediment trapping efficiency was measured in the model. The main value of the observed sediment trapping efficiencies, in the range from 13 to 55%, was a comparative assessment of various BGS designs. In general, larger cells (footprint 10 × 10 cm) were more effective than the smaller cells (5 × 5 cm), the cell depth exerted small influence on sediment trapping, and the cells with inclined cross-walls proved more effective in sediment trapping than the vertical cross-walls. However, the BGS with inclined cross-walls would be harder to maintain. Future studies should address an optimal cell design and testing in an actual stormwater pond.Chemical products traditionally used in the disinfection of water bodies often pose human health risks. For this reason, studies on natural coagulants such as Moringa oleifera Lam. represent an alternative for the inactivation of pathogenic microorganisms, among which is Escherichia coli. This study evaluated the effect of different concentrations of coagulants obtained from Moringa seed extracts and their protein fractions in the inactivation of E. coli during the coagulation/flocculation process. The coagulants studied were the aqueous extract, saline extract and protein fractions albumin and globulin, highlighting that the protein fractions were more effective on inactivating E. coli. The protein fraction globulin at a concentration of 10.0 mg L-1 showed bactericidal effects against E. coli within 18 min, whereas the albumin showed a bacteriostatic effect within 48 min because it isolated colonies in the sediment sample.In this study, a positively charged nanofiltration (NF) membrane was prepared by interfacial polymerization for separation of divalent cations, whereby a nanomaterial (modified graphitic carbon nitride (g-C3N4) with poly(dopamine), PDA-C3N4) was incorporated into the active layer of the NF membrane. PDA-C3N4 sheets were synthesized from g-C3N4 sheets prepared by thermal oxidation of melamine, and the preparation conditions of NF membrane were also optimized. The results show that the roughness of PDA-C3N4 embedded NF membrane decreases, and the hydrophilicity and the permeation increase. The membrane also shows high rejection for divalent cations (Mg2+, Ca2+, Ba2+, Cu2+ and Zn2+) but low rejection (36.8%) for monovalent cation (Li+), as well as good fouling resistance performance. The fabricated membrane has the potential for treatment of industrial wastewater.Solids-flux theory (SFT) and state-point analysis (SPA) are used for the design, operation and control of secondary settling tanks (SSTs). The objectives of this study were to assess uncertainties, propagating from flow and solids loading boundary conditions as well as compression settling behaviour to the calculation of the limiting flux (JL) and the limiting solids concentration (XL). The interpreted computational fluid dynamics (iCFD) simulation model was used to predict one-dimensional local concentrations and limiting solids fluxes as a function of loading and design boundary conditions. A two-level fractional factorial design of experiments was used to infer the relative significance of factors unaccounted for in conventional SPA. To move away from using semi-arbitrary safety factors, a systematic approach was proposed to calculate the maximum SST capacity by employing a factor of 23% and a regression meta-model to correct values of JL and XL, respectively - critical for abating hydraulic effects under wet-weather flow conditions.A magnetic graphene oxide nanocomposite modified by the ionic liquid 1-amino-3-methylimidazole chloride (LI-MGO) was prepared by the chemical coprecipitation method as a phenol adsorbent for the treatment of contaminated aqueous environments. https://www.selleckchem.com/products/cvn293.html The structure of the prepared nanocomposite was investigated using Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The prepared nanoparticles exhibited a BET (Brunauer-Emmett-Teller) specific surface area of 110.44 m2 g-1 and total pore volume of 0.2839 cm3 g-1. The results revealed that the adsorption process had the highest phenol removal percentage (95.3%) under optimum conditions (pH = 3, nanocomposite concentration = 0.04 g/l at room temperature). Kinetic studies showed a significant fit to the pseudo-second-order kinetic model (R2 > 0.9997) giving an equilibrium rate constant (K2) of 0.000119 gmg-1 min-1 for phenol loaded. The experimental adsorption data were better fitted with the Langmuir isotherm model than with the Freundlich isotherm model. To further investigate the phenol removal optimization process of the modified magnetic nanoparticles, and to determine the effect of each parameter on the adsorption process, the Taguchi optimization approach was used. The adsorption of these synthesized nanocomposites is among the low-cost, high-efficiency processes that can be used for the reduction/elimination of environmental pollutants, especially in aqueous environments.This paper documents the results of 12 months of monitoring of an upgraded hybrid moving bed biofilm reactor-conventional activated sludge wastewater treatment plant (MBBR-CAS WWTP). It also targets the assessment of the increment of the hydraulic load on existing treatment units with a zero construction and land cost. The influent flow to the plant was increased from 21,000 m3 d-1 to 30,000 m3 d-1, 40% of the existing CAS reactor volume was used for the MBBR zone with a carrier fill fraction of 47.62% and with Headworks Bio ActiveCell™ 515 used as media; no modifications were made for the primary and secondary tanks. The hybrid reactor showed high removal efficiencies for biochemical oxygen demand (BOD5), chemical oxygen demand (COD) and total suspended solids (TSS), with average effluent values recording 33.00 ± 8.87 mg L-1, 52.90 ± 9.65 mg L-1 and 29.50 ± 6.64 mg L-1 respectively. Nutrient removals in the hybrid modified biological reactor were moderate compared with carbon removal despite the high C/N ratio of 12.
The cross plots of diagnostic ratios also confirmed coal and wood combustion and traffic emissions in the region.Stormwater sediments of various sizes and densities are recognised as one of the most important stormwater quality parameters that can be conventionally controlled by settling in detention ponds. The bottom grid structure (BGS) is an innovative concept proposed in this study to enhance removal of stormwater sediments entering ponds and reduce sediment resuspension. This concept was studied in a hydraulic scale model with the objective of elucidating the effects of the BGS geometry on stormwater sediment trapping. Towards this end, the BGS cell size and depth, and the cell cross-wall angle were varied for a range of flow rates, and the sediment trapping efficiency was measured in the model. The main value of the observed sediment trapping efficiencies, in the range from 13 to 55%, was a comparative assessment of various BGS designs. In general, larger cells (footprint 10 × 10 cm) were more effective than the smaller cells (5 × 5 cm), the cell depth exerted small influence on sediment trapping, and the cells with inclined cross-walls proved more effective in sediment trapping than the vertical cross-walls. However, the BGS with inclined cross-walls would be harder to maintain. Future studies should address an optimal cell design and testing in an actual stormwater pond.Chemical products traditionally used in the disinfection of water bodies often pose human health risks. For this reason, studies on natural coagulants such as Moringa oleifera Lam. represent an alternative for the inactivation of pathogenic microorganisms, among which is Escherichia coli. This study evaluated the effect of different concentrations of coagulants obtained from Moringa seed extracts and their protein fractions in the inactivation of E. coli during the coagulation/flocculation process. The coagulants studied were the aqueous extract, saline extract and protein fractions albumin and globulin, highlighting that the protein fractions were more effective on inactivating E. coli. The protein fraction globulin at a concentration of 10.0 mg L-1 showed bactericidal effects against E. coli within 18 min, whereas the albumin showed a bacteriostatic effect within 48 min because it isolated colonies in the sediment sample.In this study, a positively charged nanofiltration (NF) membrane was prepared by interfacial polymerization for separation of divalent cations, whereby a nanomaterial (modified graphitic carbon nitride (g-C3N4) with poly(dopamine), PDA-C3N4) was incorporated into the active layer of the NF membrane. PDA-C3N4 sheets were synthesized from g-C3N4 sheets prepared by thermal oxidation of melamine, and the preparation conditions of NF membrane were also optimized. The results show that the roughness of PDA-C3N4 embedded NF membrane decreases, and the hydrophilicity and the permeation increase. The membrane also shows high rejection for divalent cations (Mg2+, Ca2+, Ba2+, Cu2+ and Zn2+) but low rejection (36.8%) for monovalent cation (Li+), as well as good fouling resistance performance. The fabricated membrane has the potential for treatment of industrial wastewater.Solids-flux theory (SFT) and state-point analysis (SPA) are used for the design, operation and control of secondary settling tanks (SSTs). The objectives of this study were to assess uncertainties, propagating from flow and solids loading boundary conditions as well as compression settling behaviour to the calculation of the limiting flux (JL) and the limiting solids concentration (XL). The interpreted computational fluid dynamics (iCFD) simulation model was used to predict one-dimensional local concentrations and limiting solids fluxes as a function of loading and design boundary conditions. A two-level fractional factorial design of experiments was used to infer the relative significance of factors unaccounted for in conventional SPA. To move away from using semi-arbitrary safety factors, a systematic approach was proposed to calculate the maximum SST capacity by employing a factor of 23% and a regression meta-model to correct values of JL and XL, respectively - critical for abating hydraulic effects under wet-weather flow conditions.A magnetic graphene oxide nanocomposite modified by the ionic liquid 1-amino-3-methylimidazole chloride (LI-MGO) was prepared by the chemical coprecipitation method as a phenol adsorbent for the treatment of contaminated aqueous environments. https://www.selleckchem.com/products/cvn293.html The structure of the prepared nanocomposite was investigated using Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The prepared nanoparticles exhibited a BET (Brunauer-Emmett-Teller) specific surface area of 110.44 m2 g-1 and total pore volume of 0.2839 cm3 g-1. The results revealed that the adsorption process had the highest phenol removal percentage (95.3%) under optimum conditions (pH = 3, nanocomposite concentration = 0.04 g/l at room temperature). Kinetic studies showed a significant fit to the pseudo-second-order kinetic model (R2 > 0.9997) giving an equilibrium rate constant (K2) of 0.000119 gmg-1 min-1 for phenol loaded. The experimental adsorption data were better fitted with the Langmuir isotherm model than with the Freundlich isotherm model. To further investigate the phenol removal optimization process of the modified magnetic nanoparticles, and to determine the effect of each parameter on the adsorption process, the Taguchi optimization approach was used. The adsorption of these synthesized nanocomposites is among the low-cost, high-efficiency processes that can be used for the reduction/elimination of environmental pollutants, especially in aqueous environments.This paper documents the results of 12 months of monitoring of an upgraded hybrid moving bed biofilm reactor-conventional activated sludge wastewater treatment plant (MBBR-CAS WWTP). It also targets the assessment of the increment of the hydraulic load on existing treatment units with a zero construction and land cost. The influent flow to the plant was increased from 21,000 m3 d-1 to 30,000 m3 d-1, 40% of the existing CAS reactor volume was used for the MBBR zone with a carrier fill fraction of 47.62% and with Headworks Bio ActiveCell™ 515 used as media; no modifications were made for the primary and secondary tanks. The hybrid reactor showed high removal efficiencies for biochemical oxygen demand (BOD5), chemical oxygen demand (COD) and total suspended solids (TSS), with average effluent values recording 33.00 ± 8.87 mg L-1, 52.90 ± 9.65 mg L-1 and 29.50 ± 6.64 mg L-1 respectively. Nutrient removals in the hybrid modified biological reactor were moderate compared with carbon removal despite the high C/N ratio of 12.
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