The hydrodynamic filter separator for removal of urban storm runoff

2006 ◽  
Vol 53 (7) ◽  
pp. 243-252 ◽  
Author(s):  
J.H. Lee ◽  
K.W. Bang ◽  
Y.J. Cho ◽  
S.J. Joh
Keyword(s):  
Particle Size ◽  
Loading Rate ◽  
Solid Particles ◽  
Storm Runoff ◽  
Surface Loading ◽  
Loading Rates ◽  
Operation Conditions ◽  
Solids Separation ◽  
Series Of Experiments ◽  
Urban Storm

The majority of storm runoff pollution is trapped in particles smaller than 100 μm in diameter. Solid particles smaller than 100 μm in diameter are not easily separated by conventional types of hydrodynamic separator, and remain in suspension in overflow. To overcome this problem, a HDFS (hydrodynamic filter separator) has been developed for treatment of the microparticles in urban storm runoff. We conducted a laboratory scale study on treatable potential of microparticles using HDFS that combined HDS with perlite filter. To determine the efficiency for various operation conditions, a series of experiments was performed with different solids concentrations and surface loading rate. The operation ranges of surface loading rates were 100 to 2,800 m3/m2/day, and influent solids concentrations were varied from 800 to 1,900 mg/L. Also, the particle size distribution was monitored to investigate the effects of surface loading rates on the particle size. Results indicated that the HDFS-Inside type showed greater efficiency at solids separation than the other type.

Characteristics of Pesticides Runoff from Golf Links

1992 ◽  
Vol 25 (11) ◽  
pp. 85-92 ◽  
Author(s):  
M. Sudo ◽  
T. Kunimatsu
Keyword(s):  
Water Samples ◽  
Loading Rate ◽  
Storm Runoff ◽  
Storm Events ◽  
Runoff Water ◽  
Detection Rates ◽  
Forested Area ◽  
Loading Rates ◽  
Runoff Event ◽  
Runoff Events

The concentration and the loading rate of pesticides were investigated in a streamlet flowing through a golf links. The water samples were collected once a week for a year and during three storm runoff events (23.9-188mm). From the 50 weekly observations, the herbicides Simazin, Oxadiazon and Atrazine, and the insecticide Diazinon were detected. Atrazine, however, was not listed on the application record obtained from the golf links. The net average concentrations of pesticides discharged from the golf links were 0.92, 0.61, 0.28 and 0.04 µg/l, respectively, and their detection rates were 98, 60, 62 and 92%, respectively. Fenitrothion and Fenthion. though listed on the applications, were not detected. None of these pesticides contaminated the runoff water from the neighboring upstream forested area. The concentrations of pesticides varied to a great extent with each storm runoff event. The loading rates of pesticides caused by the storm runoff depended on the length of the period after the applications rather than being correlated with precipitation. Using the data obtained from the regular observation and the storm runoff events, the annual loading rates of Simazin, Oxadiazon, Diazinon and Atrazine were calculated as 1,590, 362, 99.0 and 295 g/km2/year. The loadings from only three storm events observed in the study occupied 22 - 100% of these annual loadings. The annual discharging rates of Simazin, Oxadiazon and Diazinon were 4.2, 1.5, and 0.98%, respectively.

Modelling the global efficiency of dissolved air flotation

2001 ◽  
Vol 43 (8) ◽  
pp. 159-166 ◽  
Author(s):  
D. M. Leppinen ◽  
S. B. Dalziel ◽  
P. F. Linden
Keyword(s):  
Particle Size ◽  
Bubble Size ◽  
High Surface ◽  
Surface Loading ◽  
Dissolved Air Flotation ◽  
Loading Rates ◽  
Air Flotation ◽  
Bubble Attachment ◽  
Attachment Process ◽  
Dissolved Air

The purpose of this paper is to examine how the efficiency of dissolved air flotation is affected by the size of bubbles and particles. The rise speed of bubble/particle agglomerates is modelled as a function of bubble and particle size, while the kinematics of the bubble attachment process is modelled using the population balance approach adopted by Matsui, Fukushi and Tambo. It is found that flotation, in general, is enhanced by the use of larger particles and larger bubbles. In particular, it is concluded that for the ultra-high surface loading rates of 25 m/hr or more planned for future flotation tanks, bubble size will have to be increased by a factor of two over the size currently employed in many facilities during dissolved air flotation.

Research on combined cage-in-pond culture systems for South-East Asia.

2020 ◽  
Author(s):  
James Diana
Keyword(s):  
Nile Tilapia ◽  
Loading Rate ◽  
Nutrient Retention ◽  
Fertilization Rate ◽  
Waste Products ◽  
Efficient System ◽  
Loading Rates ◽  
Pond Culture ◽  
Clarias Macrocephalus ◽  
Series Of Experiments

Abstract Submerging a cage within a pond and intensively feeding fish in the cage is one method of using the waste products from cage culture in semi-intensive pond culture. Using hybrid walking catfish, Clarias macrocephalus x C. gariepinus, in cages and Nile tilapia, Oreochromis niloticus, at large in ponds, treatments of one or two cages per pond produced better results than higher stocking densities. These treatments resulted in net fish yields as high as 56 tonnes ha-1 yr-1, and the most efficient system in terms of nutrient retention was using one cage per pond. The systems with one cage per pond delivered 3.7 kg of nitrogen (N) and 1.0 kg of phosphorus (P) ha-1 d-1, and retained 48% of the N added in fish, whereas two cages resulted in 34% N retention. For P, the results were 61 and 42% retained in fish, respectively. This aquaculture system resulted in some reduction in nutrient enrichment of ponds compared to feeding alone. A second series of experiments conducted using large Nile tilapia in cages, with small Nile tilapia in the pond, showed the best results when cages were stocked at 50 fish m-3 and the pond at 1.4 fish m-3. Survival was 98.8% for caged tilapia, which grew from 120 to 456 g in 90 days, with a net annual yield of 18 tonnes ha-1. Open-pond tilapia grew from 16 to 124 g with 92% survival and a net annual yield of 6.2 tonnes ha-1. The daily waste loading rate was approximately 1.7 kg of N and 0.37 kg of P ha-1, lower than the optimal fertilization rate proposed by CRSP experiments of 4 kg of N and 1 kg of P. Caged and pond fish accounted for about 50% of the N applied to the pond and about 60% of the P. The dynamics of oxygen, ammonium and plankton were evaluated against total loading rates for all culture combinations. Oxygen levels declined dramatically (about 75-100%) in all loading rates of ponds and never reached levels approaching zero decline in oxygen. N increased with increased loading density of fish and a level of zero change in ammonium would occur at a loading rate of about 0.8 kg m-3. Plankton dynamics showed similar results, and a fish loading rate with zero change in chlorophyll a should occur at a loading rate of about 0.3 kg m-3. These results indicate that it may be possible to reduce N and plankton contents in effluent water, but doing so would require loading rates that are not economically feasible.

Degasification of mixed liquor improves settling and biological nutrient removal

2010 ◽  
Vol 5 (1) ◽  
Author(s):  
M. Maciejewski ◽  
J. A. Oleszkiewicz ◽  
A. Golcz ◽  
A. Nazar
Keyword(s):  
Nutrient Removal ◽  
Gas Bubbles ◽  
Biological Nutrient Removal ◽  
Surface Loading ◽  
Nitrogen Gas ◽  
Mixed Liquor ◽  
Loading Rates ◽  
Dissolved Nitrogen ◽  
Solids Separation ◽  
Sludge Settling

Degasification of mixed liquor by subjecting it to vacuum is a physical process used in biological nutrient removal (BNR) to improve settleability and allow for achieving higher mixed liquor suspended solids (MLSS). Vacuum degassing installation is located between the last cell of the bioreactor and secondary clarifiers. In this process two operations are performed: gas bubbles contained in mixed liquor leaving the bioreactor are removed and concentration of gasses (mainly nitrogen gas) dissolved in the liquid is reduced. Lack of gas bubbles and concentration of dissolved nitrogen gas below saturation in mixed liquor significantly improved sludge settling in secondary clarifiers and eliminated floating scum formation. Presented settleability tests of degasified MLSS and return activated sludge (RAS) from various BNR facilities showed continued settling and/or thickening for over 3 h at room temperature, without exhibiting any solids separation. Settleability tests of biomass that was not degasified typically led to flotation of portion of the sludge after about 1.5 h. Plants equipped with vacuum degasification consistently operate at larger than typically recommended final clarifier sludge surface loading rates. Rates as high as 180-220 kg TSS/m2d and deep sludge blankets have been employed. Such plants were shown to maintain operational levels of MLSS at 4500 to 6000 mg/L and higher.

scholarly journals Efficiency of tube settler on removal of roagulated particles

2019 ◽  
Vol 85 ◽  
pp. 07012
Author(s):  
Sofyan Al-Dulaimi ◽  
Gabriel Racoviţeanu
Keyword(s):  
High Efficiency ◽  
Loading Rate ◽  
Laboratory Model ◽  
Meat Industry ◽  
Surface Loading ◽  
Practical Applications ◽  
Loading Rates ◽  
Inclination Angles ◽  
Multiple Variables ◽  
Inner Diameter

Tube settler systems are one of the practical applications of the shallow sedimentation theory, which was originally developed to improve the performance of conventional sedimentation systems. The efficiency of these systems depends on multiple variables. In this paper, the influence of the tube settler unit at different inclination angles of 60°, 54°, and 48° and at different surface loading rates 2.4 to 0.42 m3/m2.h upon the coagulated particles has been investigated. A laboratory model has been designed and constructed for this purpose, which basically consists of coagulation-flocculation unit followed by tube settler unit. Tube settler unit consists of four separate circular tubes of 27mm inner diameter, with a length of 150cm each. Through the results, tube settler showed high efficiency in removing coagulated particles resulted from the chemical treatment of meat industry effluents. With respect to removal efficiency, it was observed that the change in the surface loading rate had a greater effect than the change in the inclination angle of the tubes. Also, the results indicated that there was a significant improvement in the flow pattern with the reduction in the Reynolds number, within the sedimentation unit, especially in the upper and lower zones of the tubes.

Investigation of the different particle size dust releases from rigid filter candles during pulse-jet cleaning

2021 ◽  
pp. 095440622110179
Author(s):  
Xin Luan ◽  
Zhongli Ji ◽  
Longfei Liu ◽  
Ruifeng Wang
Keyword(s):  
Particle Size ◽  
Critical Role ◽  
Operating Conditions ◽  
Solid Particles ◽  
Dust Particles ◽  
Cleaning Efficiency ◽  
Term Operation ◽  
Cleaning Performance ◽  
Experimental Apparatus ◽  
Pulse Jet

Rigid filters made of ceramic or metal are widely used to remove solid particles from hot gases at temperature above 260 °C in the petrochemical and coal industries. Pulse-jet cleaning of fine dust from rigid filter candles plays a critical role in the long-term operation of these filters. In this study, an experimental apparatus was fabricated to investigate the behavior of a 2050 mm filter candle, which included monitoring the variation of pressure dynamic characteristics over time and observing the release of dust layers that allowed an analysis of the cleaning performance of ISO 12103-1 test dusts with different particle size distributions. These results showed the release behavior of these dusts could be divided into five stages: radial expansion, axial crack, flaky release, irregular disruption and secondary deposition. The cleaning performance of smaller sized dust particles was less efficient as compared with larger sized dust particles under the same operating conditions primarily because large, flaky-shaped dust aggregates formed during the first three stages were easily broken into smaller, dispersed fragments during irregular disruption that forced more particles back to the filter surface during secondary deposition. Also, a “low-pressure and long-pulse width” cleaning method improved the cleaning efficiency of the A1 ultrafine test dust from 81.4% to 95.9%.

Penetration Dynamics of Solid Particles into Liquids High-Speed Experimental Results and Modelling

2005 ◽  
Vol 473-474 ◽  
pp. 429-434 ◽  
Author(s):  
Olga Verezub ◽  
György Kaptay ◽  
Tomiharu Matsushita ◽  
Kusuhiro Mukai
Keyword(s):  
Contact Angle ◽  
Particle Size ◽  
Aqueous Solutions ◽  
Particle Velocity ◽  
Weber Number ◽  
High Speed ◽  
Solid Particles ◽  
Bulk Liquid ◽  
Distilled Water ◽  
Critical Weber Number

Penetration of model solid particles (polymer, teflon, nylon, alumina) into transparent model liquids (distilled water and aqueous solutions of KI) were recorded by a high speed (500 frames per second) camera, while the particles were dropped from different heights vertically on the still surface of the liquids. In all cases a cavity has been found to form behind the solid particle, penetrating into the liquid. For each particle/liquid combination the critical dropping height has been measured, above which the particle was able to penetrate into the bulk liquid. Based on this, the critical impact particle velocity, and also the critical Weber number of penetration have been established. The critical Weber number of penetration was modelled as a function of the contact angle, particle size and the ratio of the density of solid particles to the density of the liquid.

Field study on N2O emission from subsurface wastewater infiltration system under variable loading rates and drying-wetting cycles

2017 ◽  
Vol 76 (8) ◽  
pp. 2158-2166 ◽  
Author(s):  
Ying-Hua Li ◽  
Hai-Bo Li ◽  
Xin-Yang Xu ◽  
Si-Yao Xiao ◽  
Si-Qi Wang ◽  
...  
Keyword(s):  
Field Study ◽  
Conversion Rate ◽  
Oxygen Demand ◽  
N2o Emission ◽  
Conversion Ratio ◽  
Gas Chromatograph ◽  
Variable Loading ◽  
N2o Production ◽  
Loading Rates ◽  
Operation Conditions

In this field study, the impacts of influent loadings and drying-wetting cycles on N2O emission in a subsurface wastewater infiltration (SWI) system were investigated. N2O emitted under different operation conditions were quantified using static chamber and gas chromatograph techniques. N2O conversion rate decreased from 6.6 ± 0.1% to 2.7 ± 0.1% with an increase in hydraulic loading (HL) from 0.08 to 0.24 m3/m2·d. By contrast, N2O conversion rate increased with increasing pollutant loading (PL) up to 8.2 ± 0.5% (PL 4.2 g N/m2·d) above which conversion rate decreased, confirming that N2O production was under the interaction of nitrification and denitrification. Taking into consideration the pollutants (chemical oxygen demand (COD), NH4+-N, NO3−-N and total nitrogen (TN)) removal ratio and N2O emission, optimal loading ranges and drying-wetting modes were suggested as HL 0.08–0.12 m3/m2·d, PL 3.2–3.7 g N/m2·d and 12 h:12 h, respectively. The results revealed that in SWI systems, conversion ratio of influent nitrogen to N2O could be between 4.5% and a maximum of 7.0%.

Numerical Study on the Erosion Characteristics of U-Type Bend for Gas Solid Flow

2017 ◽  
Author(s):  
Yu Wang ◽  
Qi He ◽  
Ming Liu ◽  
Weixiong Chen ◽  
Junjie Yan
Keyword(s):  
Particle Size ◽  
Erosion Rate ◽  
Loading Rate ◽  
Pipe Wall ◽  
Numerical Study ◽  
Pulverized Coal ◽  
Mass Loading ◽  
Two Phase ◽  
Inlet Velocity ◽  
Pipe System

In pulverized coal-fired plant, the U-type bend is commonly used in flue gas and pulverized coal pipe system to due to the constraints of outer space. And gas-solid two-phase flow exists in these pipelines. The erosion of the pipe has significant effect on the safety and reliability of pipelines. In present paper, the erosion characteristics of U-type bend were investigated through CFD (Computational Fluid Dynamics) method. The wear distribution on the pipe wall was obtained. And the particle flow characteristics in U-type bend were analyzed. The influence of inlet velocity, mass loading rate and particle size on the erosion rate was studied as well. Result suggested that the maximum erosion rate increases exponentially with the increase of inlet velocity. And maximum erosion rate increases linearly with the increasing mass loading rate. Increasing particle size can aggravate the wear on the pipe wall.

Coarse filters for pond effluent polishing: comparison of loading rates and grain sizes

2007 ◽  
Vol 55 (11) ◽  
pp. 121-126 ◽  
Author(s):  
M. von Sperling ◽  
J.G.B. de Andrada ◽  
W.R. de Melo Júnior
Keyword(s):  
Loading Rate ◽  
Uasb Reactor ◽  
E Coli ◽  
Effluent Quality ◽  
Loading Rates ◽  
Hydraulic Loading ◽  
Grain Sizes ◽  
Belo Horizonte ◽  
The City ◽  
Rock Size

A system comprising a UASB reactor, shallow polishing ponds and shallow coarse filters, treating actual wastewater from the city of Belo Horizonte, Brazil, has been evaluated. The main focus of the research was to compare grain sizes and hydraulic loading rates in the coarse filters. Two filters operating in parallel were investigated, with the following grain sizes: Filter 1: 3 to 10 cm; Filter 2: 8 to 20 cm. Two hydraulic loading rates were tested: 0.5 and 1.0 m3/m3.d. The filter with the lower rock size had a better performance than the filter with the larger rock size in the removal of SS and, as a consequence, BOD and COD. A better performance was obtained with the hydraulic loading rate of 0.5 m3/m3.d, as compared to the rate of 1.0 m3/m3.d. The effluent quality during the period with the lower loading rate was very good for discharge into water bodies or for agricultural reuse (median effluent concentrations from Filter 1: BOD: 20 mg/L; COD: 106 mg/L; SS: 28 mg/L; E. coli: 528 MPN/100 mL).

Sign in / Sign up

Export Citation Format

Share Document