Simulation on combined rapid gravity filtration and backwash models

2009 ◽  
Vol 59 (12) ◽  
pp. 2429-2435 ◽  
Author(s):  
S. J. Han ◽  
C. S. B. Fitzpatrick ◽  
A. Wetherill
Keyword(s):  
Removal Efficiency ◽  
Flow Rate ◽  
Air Flow ◽  
Experimental Results ◽  
Particle Removal ◽  
Air Flow Rate

Combined rapid gravity filtration and backwash models have been applied to simulate filtration and backwash cycles. The simulated results from the backwash model suggest that an optimum air flow rate exists to maximise particle removal efficiency in the backwash operation for a certain backwash system. The simulation of combined rapid gravity filtration and backwash models suggests that the filter shouldn't be completely cleaned up in the backwash and a certain amount of particles retained on filter grains after backwash can be beneficial for subsequent filtration runs. This is consistent with the experimental results in the literature.

Separation and Hydrodynamic Performance of Air-Kerosene-Water System by Bubble Column

2010 ◽  
Vol 8 (1) ◽  
Author(s):  
Abbas H. Sulaymon ◽  
Ahmed Abed Mohammed
Keyword(s):  
Removal Efficiency ◽  
Flow Rate ◽  
Bubble Column ◽  
Removal Rate ◽  
Air Flow ◽  
Bubble Diameter ◽  
Water Concentration ◽  
Hydrodynamic Performance ◽  
Air Flow Rate ◽  
Flotation Process

The separation of emulsified kerosene in water (concentration 250-750ppm) was investigated in a bubble column15.6 cm diameter and 120 cm height. The effective behaviors of bubble characteristics (bubble diameter, bubble rise velocity and air hold-up) on the removal efficiency were measured by electroresistivity probe. The effects of kerosene concentration, air flow rate,bubble diameter, liquid height, liquid viscosity, NaCl concentration, and alum on the removal rate were found. The experimental results showed that the removal efficiency increased with increasing air flow rate (1.09-2.6cm/s) and decreased with increasing CMC concentration. The results also showed that adding anionic surfactants (SLES and SDBS) leads to increase removal rate. The the flotation process was found to be first order kinetics. New correlations of air holdup and bubble diameter using dimensionless groups were derived.

scholarly journals Toluene Removal from Sandy Soils via In Situ Technologies with an Emphasis on Factors Influencing Soil Vapor Extraction

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Mohammad Mehdi Amin ◽  
Mohammad Sadegh Hatamipour ◽  
Fariborz Momenbeik ◽  
Heshmatollah Nourmoradi ◽  
Marzieh Farhadkhani ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Flow Rate ◽  
Air Flow ◽  
Sandy Soils ◽  
Air Injection ◽  
Combination Method ◽  
Soil Vapor Extraction ◽  
Air Flow Rate ◽  
Vapor Extraction ◽  
Toluene Removal

The integration of bioventing (BV) and soil vapor extraction (SVE) appears to be an effective combination method for soil decontamination. This paper serves two main purposes: it evaluates the effects of soil water content (SWC) and air flow rate on SVE and it investigates the transition regime between BV and SVE for toluene removal from sandy soils. 96 hours after air injection, more than 97% removal efficiency was achieved in all five experiments (carried out for SVE) including 5, 10, and 15% for SWC and 250 and 500 mL/min for air flow rate on SVE. The highest removal efficiency (>99.5%) of toluene was obtained by the combination of BV and SVE (AIBV: Air Injection Bioventing) after 96 h of air injection at a constant flow rate of 250 mL/min. It was found that AIBV has the highest efficiency for toluene removal from sandy soils and can remediate the vadose zone effectively to meet the soil guideline values for protection of groundwater.

scholarly journals GUIDELINES FOR THE DESIGN OF AIR BUBBLE SYSTEMS

1976 ◽  
Vol 1 (15) ◽  
pp. 170
Author(s):  
Nabil Ismail
Keyword(s):  
Pressure Drop ◽  
Flow Rate ◽  
Air Flow ◽  
Water Systems ◽  
Experimental Results ◽  
Air Flow Rate ◽  
Air Bubble ◽  
Proper Design ◽  
Comprehensive Study ◽  
The Ideal

Based on a literature review of theoretical and experimental work on air-bubble systems, guidelines for the ideal design of submerged distributors discharging air into water are presented. A comprehensive study of gas-liquid dispersions was carried out to find out the effect of physical properties, distributor arrangement, and the air flow rate, on the flow pattern within the jet. This review revealed that the distributor arrangement largely influences the characteristics of the dispersion within the zone of flow establishment. Also, upon analyzing the experimental results of air-water systems, it was found that the zone of flow establishment extends to greater distances of the water depth than that in the case of one-phase turbulent plumes. Furthermore, the experimental results showed that the efficiency of air bubble plumes can be increased by the proper design of the distributor. Recommendations for the distributor design are given, which include, diameter of orifices and their spacings, pressure drop across orifices, number of manifolds, and the maximum air flow rate.

Effect of Temperature and Air flow rate on Xylene Removal from Wastewater using Packed Column Air Stripper

2014 ◽  
Vol 67 (4) ◽  
Author(s):  
Hamidah Kamarden ◽  
Mohd. Ariffin Abu Hassan ◽  
Zainura Zainon Noor ◽  
RK Raja Ibrahim ◽  
Abdullahi Mohammed Evuti
Keyword(s):  
Removal Efficiency ◽  
Flow Rate ◽  
Linear Trend ◽  
Air Flow ◽  
Packed Column ◽  
Effect Of Temperature ◽  
Air Flow Rate ◽  
Column Temperature ◽  
Percentage Removal ◽  
Effects Of Temperature

In this research, the effects of temperature and air flow rate on the removal efficiency of xylene from wastewater using packed column air stripper were investigated at a temperature range of 30 to 500C and air-water ratios of 20 to 100. The quantities of xylene in effluent from the air stripper were determined using UV-visible spectrophotometer. The effects of increase in temperature on the percentage removal of xylene were found to be more significant at low temperatures (30-400C) than at higher temperatures (45-500C). Also, the effects of increase in water-air ratio on percentage removal of xylene were less significant at higher G/L ratio (80-100) and more significant at low G/L ratios (20-60), thus revealing a non-linear trend in the effect of temperature and air-water ratio on xylene removal.The result also indicates that xylene removal efficiency is greatly affected by column temperature and G/L ratio with the highest removal efficiency of 99.93 at temperature of 500C and at G/L ratio of 100.

Removal of NH3 in Air Released from Rubber Latex Process Using Skim Serum Absorbent

2013 ◽  
Vol 844 ◽  
pp. 441-444
Author(s):  
Siranat Pansang ◽  
Preecha Kasikamphaiboon ◽  
Juntima Chungsiriporn
Keyword(s):  
Removal Efficiency ◽  
Flow Rate ◽  
Pure Water ◽  
Air Flow ◽  
Liquid Waste ◽  
Industrial Scale ◽  
Water Usage ◽  
Air Flow Rate ◽  
Treatment Efficiency ◽  
Rubber Latex

The treatment of NH3 releasing concentrated rubber latex to air was studied using skim serum in laboratory scale of bubble absorption reactor. The skim serum (pH 2.5 to 3) is a liquid waste from concentrated rubber latex. The concentration of NH3 in air (300 to 1500 ppmv) and air flow rate (0.5 to 1.5 l/min) feeding into the reactor were measured for the effect of the treatment efficiency. At lower NH3 concentration and air flow rate have resulted to higher NH3 removal efficiency. Bubble absorption reactor can be effectively used and applied to remove NH3 releasing from the concentrated rubber latex process to the air without any plugging of the skim rubber in the system. Skim serum waste liquid has the result in higher efficiency in NH3 removal comparing to pure water usage. This study would be practically used as a guidance for the further design and operate to minimize waste and emission control in rubber industrial-scale system.

scholarly journals Ammonia nitrogen removal and recovery from acetylene purification wastewater by air stripping

2017 ◽  
Vol 75 (11) ◽  
pp. 2538-2545 ◽  
Author(s):  
Lei Zhu ◽  
DeMing Dong ◽  
XiuYi Hua ◽  
Yang Xu ◽  
ZhiYong Guo ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Flow Rate ◽  
Air Flow ◽  
Ammonia Nitrogen ◽  
Operating Conditions ◽  
H2so4 Solution ◽  
Air Flow Rate ◽  
Air Stripping ◽  
Experimental Conditions ◽  
N Removal

Ammonia nitrogen (NH4-N) contaminated wastewater has posed a great threat to the safety of water resources. In this study, air stripping was employed to remove and recover NH4-N from acetylene purification wastewater (APW) in a polyvinylchloride manufacturing plant. Investigated parameters were initial APW pH, air flow rate, APW temperature and stripping time. The NH4-N removal by air stripping has been modeled and the overall volumetric mass transfer coefficient (KLa) of the stripping process has been calculated from the model equation obtained. In addition, the ability of H2SO4 solution to absorb the NH3 stripped was also investigated. The results indicated that under the experimental conditions, the APW temperature and its initial pH had significant effects on the NH4-N removal efficiency and the KLa, while the effects of other factors were relatively minor. The removal efficiency and residual concentration of NH4-N were about 91% and 12 mg/L, respectively, at the optimal operating conditions of initial APW pH of 12.0, air flow rate of 0.500 m3/(h·L), APW temperature of 60 °C and stripping time of 120 min. One volume of H2SO4 solution (0.2 mol/L) could absorb about 93% of the NH3 stripped from 54 volumes of the APW.

Removal of trichloroethylene and trichloroethane using a novel hollow-fibre gas-permeable membrane

2003 ◽  
Vol 3 (5-6) ◽  
pp. 67-72
Author(s):  
S. Takizawa ◽  
T. Win
Keyword(s):  
Boundary Layer ◽  
Flow Regime ◽  
Removal Efficiency ◽  
Residence Time ◽  
Flow Rate ◽  
Air Flow ◽  
Hollow Fibre ◽  
Permeation Rate ◽  
Permeable Membrane ◽  
Diffusional Boundary Layer

In order to evaluate effects of operational parameters on the removal efficiency of trichloroethylene and 1,1,1-trichloroethene from water, lab-scale experiments were conducted using a novel hollow-fibre gaspermeable membrane system, which has a very thin gas-permeable membrane held between microporous support membranes. The permeation rate of chlorinated hydrocarbons increased at higher temperature and water flow rate. On the other hand, the effects of the operational conditions in the permeate side were complex. When the permeate side was kept at low pressure without sweeping air (pervaporation), the removal efficiency of chlorinated hydrocarbon, as well as water permeation rate, was low probably due to lower level of membrane swelling on the permeate side. But when a very small amount of air was swept on the membrane (air perstripping) under a low pressure, it showed a higher efficiency than in any other conditions. Three factors affecting the permeation rate are: 1) reduction of diffusional boundary layer within the microporous support membrane, 2) air/vapour flow regime and short cutting, and 3) the extent of membrane swelling on the permeate side. A higher air flow, in general, reduces the diffusional boundary layer, but at the same time disrupts the flow regime, causes short cutting, and makes the membrane dryer. Due to these multiple effects on gas permeation, there is an optimum operational condition concerning the vacuum pressure and the air flow rate. Under the optimum operational condition, the residence time within the hollow-fibre membrane to achieve 99% removal of TCE was 5.25 minutes. The log (removal rate) was linearly correlated with the average hydraulic residence time within the membrane, and 1 mg/L of TCE can be reduced to 1 μg/L (99.9% removal).

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