Particle retention in compact constructed wetlands treating highway stormwater

2014 ◽  
Vol 69 (7) ◽  
pp. 1440-1446 ◽  
Author(s):  
Yaoping Chen ◽  
Kisoo Park ◽  
Youngchul Kim
Keyword(s):  
Particle Size ◽  
Pilot Scale ◽  
High Porosity ◽  
Treatment Tank ◽  
Micro Particles ◽  
Sedimentation Tank ◽  
Operational Lifetime ◽  
Copper Zinc ◽  
Pre Treatment ◽  
Positive Effect

Three pilot-scale compact constructed wetland systems were constructed to treat stormwater from a highway. They each comprised a sedimentation tank, and a vertical flow (VF) wetland bed equipped with a recirculation device. The VF wetland beds were filled with woodchip, pumice and volcanic gravel, respectively. According to the analysis of the particle size distributions (0.52–500 μm), the predominant particles in stormwater ranged in size from 0.52–30 μm. In the sedimentation tank, with a 24 h settling time, the settling efficiencies of the particles increased with increasing particle size. In the VF wetland beds, further capture of the particles was achieved; however, the woodchip and volcanic gravel wetlands displayed relatively low trapping of micro-particles, due to the natural properties of the substrates. Recirculation caused a positive effect on the retention of particles in the woodchip wetland. Due to the employment of a pre-treatment tank and the high porosity of materials, the accumulated solids occupied very low proportions of the pore volume in the wetland substrates. The results also showed that the accumulation of copper, zinc and lead do not pose a problem for the disposal of the substrates when the wetlands reach the end of their operational lifetime.

Metallic pollution in clogging materials of urban porous pavements

1995 ◽  
Vol 32 (1) ◽  
pp. 57-62 ◽  
Author(s):  
Valérie Colandini ◽  
Michel Legret ◽  
Yves Brosseaud ◽  
Jean-Daniel Baladès
Keyword(s):  
Heavy Metal ◽  
Particle Size ◽  
Road Traffic ◽  
Total Concentration ◽  
Extraction Procedure ◽  
Interaction Strength ◽  
Metal Mobility ◽  
Residual Fraction ◽  
Metal Contents ◽  
Copper Zinc

Porous pavements infiltrated with stormwater are faced with clogging problems: runoff particles seep and clog the pervious surface layer of these structures. Clogging material samples (in the form of sludge) have been collected in cleaning operations on the pervious asphalt. This study aims at characterizing these materials, particle size distribution, heavy metal contents by particle size, and studying interactions between metals and particles. A sequential extraction procedure proposed by the experts of the Community Bureau of Reference (B.C.R.) was applied to provide information about heavy metal distribution on particles and to evaluate interaction strength, and consequently potential metal mobility when chemical variations occurred in the environment. Mainly made up of sand, the materials are polluted with lead, copper, zinc and cadmium. The concentrations appeared to be linked with road traffic intensity. The heavy metal contents by particle size showed that the finer are the particles, the higher are the heavy metal concentrations. Heavy metals were found potentially labile; metals contents in the residual fraction (mineral fraction) represented less than 20 % of the total concentration. Cadmium and zinc were apparently more labile than lead and copper.

Effects of surfactant and particle size on the microstructure and strength of Si3N4 foams with high porosity

2020 ◽  
Author(s):  
Zhongpei Du ◽  
Dongxu Yao ◽  
Yongfeng Xia ◽  
Kaihui Zuo ◽  
Jinwei Yin ◽  
...  
Keyword(s):  
Particle Size ◽  
High Porosity

scholarly journals Particle Size Distribution Based Occurrence Features of Organic Components in Printing and Dyeing Wastewater Under a Treatment Process

2019 ◽  
Vol 118 ◽  
pp. 04009
Author(s):  
Yuan Li ◽  
Jie Liu ◽  
Yibiao Yu ◽  
Hao Zhu ◽  
Zheng Shen ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Reverse Osmosis ◽  
Treatment Process ◽  
Dyeing Wastewater ◽  
Wastewater Treatment Process ◽  
Printing And Dyeing Wastewater ◽  
Sedimentation Tank ◽  
The Relationship

A more detailed occurrence features of organic matters in the printing and dyeing wastewater, based on its particle size distribution (PSD) and along with a wastewater treatment process, was conducted to provide a support for advanced treatment. Results suggested that, (1) In the dyeing wastewater, the occurrence characteristic of COD was: soluble>supra colloidal>colloidal>settleable; However, for protein, the supra colloidal was dominant, followed by the soluble. The feature of the polysaccharide was consistent with COD’s. In the wastewater, 29.66% of COD could be attributed to proteins and 3.45% of the COD could be attributed to polysaccharides. (2) The relationship among the forms of COD in the primary sedimentation tank, aerobic tank, secondary sedimentation tank, and reverse osmosis-treated concentrated effluent was consistent, that was: soluble>colloidal>supra colloidal>settleable. (3) In the primary sedimentation tank, the settleable COD was almost completely removed; In the aerobic tank, the residual super colloidal COD was not much; After MBR-RO treatment, the COD in the reverse osmosis concentrated water was almost dissolved and only a little presented in other forms.

Enhanced sludge conditioning by enzyme pre-treatment: comparison of laboratory and pilot scale dewatering results

2006 ◽  
Vol 54 (5) ◽  
pp. 33-41 ◽  
Author(s):  
D. Dursun ◽  
M. Turkmen ◽  
M. Abu-Orf ◽  
S.K. Dentel
Keyword(s):  
Extracellular Polymeric Substances ◽  
Treatment Plant ◽  
Pilot Scale ◽  
Solid Content ◽  
Filter Press ◽  
Treatment Comparison ◽  
Anaerobically Digested Sludge ◽  
Network Strength ◽  
Pre Treatment ◽  
Solids Content

The effect of enzyme pre-treatment on dewaterability of anaerobically digested sludge was investigated at both laboratory and pilot scale. Our results revealed a significant increase in cake solid content (27% cake solids compared to 18% without enzyme pre-treatment), using an enzyme dose of only 20 mg/L. In order to assess practical application, enzyme pre-treatment was applied at the Wilmington, Delaware (US) wastewater treatment plant, using a pilot-scale centrifuge. However, the efficiency reached in laboratory scale could not be obtained in pilot scale, where the final cake solids content did not exceed 20%. Centrifuge and belt filter press (simulated by Crown Press™) dewatering were compared in terms of the process efficiencies in the absence and presence of enzyme pre-treatment. Possible factors that might cause the differences were tested by experimental and statistical comparisons. Results indicated that the higher shear applied in centrifugation is responsible for the lack of improved cake solids. The network strength of sludge determined by rheological measurements revealed that enzymatic treatment weakens the gel structure of the sludge floc through the hydrolysis of extracellular polymeric substances; this allows improved dewatering by filtration processes, but leads to floc deterioration when subjected to high shear during centrifugation.

Highly efficient photo-degradation of cetirizine antihistamine with TiO2-SiO2 photocatalyst under ultraviolet irradiation

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Sonam Rani ◽  
Alok Garg ◽  
Neetu Singh
Keyword(s):  
Particle Size ◽  
Photocatalytic Activity ◽  
Terephthalic Acid ◽  
Cost Effective ◽  
Oh Radicals ◽  
Large Specific Surface Area ◽  
Photo Degradation ◽  
Macroscopic Structure ◽  
Bet Analysis ◽  
Positive Effect

Abstract Photocatalysis is an extraordinary and vastly researched topic; there is a need to find new ways to support producing composite materials that are cost-effective, efficient and have a low environmental impact. The investigation was undertaken on syn TiO2 by depositing it on silica. The results elucidate the positive effect on photocatalysis activity and the macroscopic structure on which the TiO2 is formed. For the analysis of photocatalyst, various characterisation measurements were undertaken, such as XRD, FTIR, DRS, FESEM, TEM, RS, and BET. The accumulated TiO2 onto the surface of SiO2 stabilised its transformation of the phase from anatase to rutile, resulting in decreased particle size and enhancing its photocatalytic activity under UV irradiation. The concentration of OH• radicals was determined using terephthalic acid as a probe molecule to determine its role in the photocatalytic degradation of antihistamine. The results of BET analysis showed that the syn TiO2-SiO2 sample has a large specific surface area of 192.6 m2 g−1. Maximum degradation of cetirizine (about 97%) was achieved with 80% TiO2-20% SiO2 (TS-4). Recyclability test confirmed that 80% TiO2-20% SiO2 sample was stable up to six cycles.

Characteristics of an air-fluidized-bed biofilm reactor system with a multi-media filter

1994 ◽  
Vol 30 (11) ◽  
pp. 101-110
Author(s):  
Toshiaki Tsubone ◽  
Seiichi Kanamori ◽  
Tatsuo Takechi ◽  
Masahiro Takahashi
Keyword(s):  
Particle Size ◽  
Fluidized Bed ◽  
Suspended Solids ◽  
Pilot Scale ◽  
Biofilm Reactor ◽  
Reactor System ◽  
Multi Media ◽  
Bod Removal

A pilot scale study was conducted using an Air-Fluidized-Bed Biofilm Reactor (AFBBR) system with a Multi Media Filter (MMF). Soluble BOD (S-BOD) concentration in the effluent of the AFBBR had a correlation with total BOD (T-BOD) and Suspended Solids (SS) concentration in the effluent of the MMF. The lower the S-BOD in the effluent of the AFBBR was, the lower was not only T-BOD but also SS in the effluent of the MMF. It was found that as treatment proceeded, S-BOD was removed and the particle size of SS increased in the AFBBR. These results suggested that the mechanism of BOD removal in this system was: S-BOD was removed and a part of the S-BOD was changed to SS and the particle size of the SS increased in the AFBBR, and then the SS was removed by the MMF. Thus not only the T-BOD but also the SS in the effluent of MMF was lower when the S-BOD in the effluent of the AFBBR was lower. When the S-BOD in the effluent of the AFBBR was 8mg/L, T-BOD and the SS in the effluent of the MMF were 10mg/L and 4mg/L, respectively. In order to have an average S-BOD value in the effluent of the AFBBR of about 8mg/L, the T-BOD loading and the S-BOD loading needed to be less than 1.3kg/m3/day and 0.45 kg/m3/day, respectively. Even when the BOD loading was high, nitrification still occurred in this system.

Use of Municipal Solid Waste Incineration Bottom Ash in Adsorption of Heavy Metals

2011 ◽  
Vol 474-476 ◽  
pp. 1099-1102
Author(s):  
Hai Ying Zhang ◽  
Yi Zheng ◽  
Hong Tao Hu ◽  
Jing Yu Qi
Keyword(s):  
Heavy Metals ◽  
Particle Size ◽  
Municipal Solid Waste ◽  
Solid Waste ◽  
Residence Time ◽  
Bottom Ash ◽  
Waste Incineration ◽  
Synthetic Wastewater ◽  
High Porosity ◽  
Municipal Solid Waste Incineration

Bottom ash from municipal solid waste incineration (MSWI) has been previously suggested as an adsorbent for removing heavy metals from wastewater due to its high porosity and large surface area. In this study the adsorption characteristics of heavy metals were investigated using various particle sizes of MSWI bottom ash. The adsorption experiment was conducted using synthetic wastewater containing Cu, Zn, Pb and Cd as a function of residence time, initial pH, ash dosage and particle size, respectively. The adsorption rate increased with decreasing particle size and with increasing residence time. Through the above analysis, this work proved that bottom ash was effective in adsorbing the four heavy metals.

Microwave-Assisted Grinding of Bolkardag (Nigde, Turkey) Gold Ore and Enhanced Cyanide Leachability

2018 ◽  
Vol 115 (5) ◽  
pp. 508 ◽  
Author(s):  
Cemaliye Seflek ◽  
Oktay Bayat
Keyword(s):  
Particle Size ◽  
Power Level ◽  
Microwave Treatment ◽  
Cyanide Leaching ◽  
Gold Ore ◽  
Work Index ◽  
Significant Difference ◽  
Bond Work Index ◽  
Pre Treatment ◽  
Silver Extraction

This experimental work aims at studying the effect of particle size on the microwave pre-treatment for the grindability of Bolkardag (Nigde, Turkey) gold ore for cyanide leaching. Three different particle size batches (−8 + 4.7 mm, −4.75 + 2 mm and −2 + 1 mm) were used for microwave treatment. Each sub-samples were exposed to four different power levels of microwave energy (0.09, 0.18, 0.36 and 0.6 kW) at exposure times of 5, 10, 15 and 30 minutes and then grindability characteristic of the treated samples were investigated with Berry and Bruce comparative grindability method. It was clearly seen that increasing power level and exposure time caused a reduction in comparative Bond Work index. A maximum reduction in Bond Work index (73.54%) was achieved by 0.6 kW at 30 minutes of microwave treatment. Compared to the untreated sample’s results, gold and silver extraction rates increased, using microwave-treated samples, about 7% and 9% after 77 hours cyanide leaching, respectively. Additionally, the hydrated lime added samples (after 0.6 kW at 30 minutes of microwave treatment) were used in the cyanide leaching tests to determine the possible effect. It was observed that there was no significant difference on leaching extraction rates using lime free or lime added samples. Applying microwave pre-treatment before cyanide leaching, the gold and silver extraction rates could be increased and also the cost of communition could be reduced due to easier breakage of the ore due to a significant decrease in Bond Work index.

scholarly journals Kinetic Behaviour of Pancreatic Lipase Inhibition by Ultrasonicated A. malaccensis and A. subintegra Leaves of Different Particle Sizes

2020 ◽  
Vol 15 (3) ◽  
pp. 818-828
Author(s):  
Miradatul Najwa Muhd Rodhi ◽  
Fazlena Hamzah ◽  
Ku Halim Ku Hamid
Keyword(s):  
Particle Size ◽  
Gallic Acid ◽  
Pancreatic Lipase ◽  
Crude Extract ◽  
Competitive Inhibition ◽  
Treatment Method ◽  
Crude Extracts ◽  
Pre Treatment ◽  
Pancreatic Lipase Inhibition ◽  
Lipase Inhibition

Gallic acid and quercetin equivalent were determined in the crude extract of matured leaves Aquilaria malaccensis and Aquilaria subintegra. The leaves of both Aquilaria species were dried at 60 °C for 24 hours, ground and sieved into particle size of 250, 300, 400, 500, and 1000 µm. Then, each particle size of leaves was soaked in distilled water with a ratio of 1:100 (w/v) for 24 hours and undergoes the pre-treatment method by using ultrasonicator (37 kHz), at the temperature of 60 °C for 30 minutes. The crude extracts were obtained after about 4 hours of hydrodistillation process. The highest concentration of gallic acid and quercetin equivalent was determined in the crude extract from the particle size of 250 µm. The kinetics of pancreatic lipase inhibition was further studied based using the Lineweaver-Burk plot, wherein the concentration of p-NPP as the substrate and pancreatic lipase were varied. Based on the formation of the lines in the plot, the crude leaves extract of both Aquilaria species exhibit the mixed-inhibition on pancreatic lipase, which indicates that in the reaction, the inhibitors were not only attached to the free pancreatic lipase, but also to the pancreatic lipase-(p-NPP) complex. The reaction mechanism was similar to non-competitive inhibition; however the value of dissociation constant, Ki, for both inhibition pathways was different. The inhibition shows an increment in Michaelis-Menten constant (Km) and a reduction in the maximum pancreatic lipase activity (Vm) compared to the reaction without Aquilaria spp. crude extracts (control). This proved that the inhibition occurred in this reaction. Copyright © 2020 BCREC Group. All rights reserved 

scholarly journals Study on indium leaching from mechanically activated hard zinc residue

2011 ◽  
Vol 47 (1) ◽  
pp. 63-72 ◽  
Author(s):  
J.H. Yao ◽  
X.H. Li ◽  
Y.W. Li
Keyword(s):  
Activation Energy ◽  
Particle Size ◽  
Planetary Mill ◽  
Leaching Rate ◽  
Obvious Effect ◽  
Diffusion Controlled ◽  
Leaching Reaction ◽  
Kinetics Of ◽  
Positive Effect ◽  
Solution Kinetics

In this study, changes in physicochemical properties and leachability of indium from mechanically activated hard zinc residue by planetary mill were investigated. The results showed that mechanical activation increased specific surface area, reaction activity of hard zinc residue, and decreased its particle size, which had a positive effect on indium extraction from hard zinc residue in hydrochloric acid solution. Kinetics of indium leaching from unmilled and activated hard zinc residue were also investigated, respectively. It was found that temperature had an obvious effect on indium leaching rate. Two different kinetic models corresponding to reactions which are diffusion controlled, [1-(1- x)1/3]2=kt and (1-2x/3)-(1-x)2/3=kt were used to describe the kinetics of indium leaching from unmilled sample and activated sample, respectively. Their activation energies were determined to be 17.89 kJ/mol (umilled) and 11.65 kJ/mol (activated) within the temperature range of 30?C to 90?C, which is characteristic for a diffusion controlled process. The values of activation energy demonstrated that the leaching reaction of indium became less sensitive to temperature after hard zinc residue mechanically activated by planetary mill.

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