The role of microparticles in dead-end ultrafiltration of wwtp-effluent

2004 ◽  
Vol 50 (12) ◽  
pp. 87-94 ◽  
Author(s):  
J.H. Roorda ◽  
S. te Poele ◽  
J.H.J.M. van der Graaf
Keyword(s):  
Wastewater Treatment Plants ◽  
Pilot Scale ◽  
Size Distributions ◽  
Particle Size Distributions ◽  
Membrane Pores ◽  
Wwtp Effluent ◽  
Dead End ◽  
Minor Influence ◽  
Pre Treatment

Ultrafiltration is considered as an interesting polishing technique for effluent of wastewater treatment plants (wwtp-effluent). Results in pilot-scale experiments indicated that microparticles might dominate the filtration characteristics. In this article the results of investigations on the role of microparticles on the filterability of effluent is described. Calculation effects on particle size distributions of effluent showed that particles smaller than 2.0 μm predominantly influence the filterability of the wwtp-effluent. Additionally, experiments were performed on the filterability of size fractions of effluent. Effluent was fractionated with laboratory filters (pore diameter 5.0, 1.2, 0.45, 0.2 and 0.1 μm). The filterability of this pre-filtered effluent in applying ultrafiltration was evaluated by measurement of the SUR, a new parameter for measurement of the filterability of effluent. The results showed that filterability of the effluent was mainly influenced by 40% to 57% by the fraction larger than 0.1 μm and smaller than 0.2 μm, which is five to twenty times larger than the ultrafiltration membrane pores. Pre-treatment of the effluent by coagulation or sand filtration showed only minor influence on these results.

Combined air-water flush in dead-end ultrafiltration

2001 ◽  
Vol 1 (5-6) ◽  
pp. 393-402 ◽  
Author(s):  
J.Q.J.C. Verbeck ◽  
G.I.M. Worm ◽  
H. Futselaar ◽  
J.C. van Dijk
Keyword(s):  
Membrane Surface ◽  
Head Loss ◽  
Direct Result ◽  
Two Phase ◽  
Sand Filters ◽  
Membrane Pores ◽  
Dead End ◽  
Pre Treatment ◽  
A New Technique ◽  
Energy Dissipated

Dead-end ultrafiltration has proven itself as a technique for reclamation of backwash water of sand filters and as a pre-treatment step for spiral wound reverse osmosis. A direct result of dead-end filtration is a decreased flux caused by the accumulation of material in the membrane pores and on the membrane surface. Different cleaning techniques are used to remove this accumulated material. Recently a new technique has been introduced, the AirFlush. This technique makes use of air to create higher turbulence as compared to a water flush. At Delft University of Technology research has started into the fundamentals of the combined air- and water-flush. First a series of experiments has been carried out to determine the different flow patterns, followed by experiments to determine which air- and water-velocities give the best cleaning. Finally head loss experiments have been done to get information about the energy dissipated in the system. The results of the head loss experiments have been compared to the theoretical head loss calculated with the theory of heterogeneous two-phase flow.

Textural properties of regoliths on vegetated steep slopes in upland regions, Scotland

1986 ◽  
Vol 77 (3) ◽  
pp. 241-250 ◽  
Author(s):  
J. L. Innes
Keyword(s):  
Particle Size ◽  
Early Stage ◽  
Probability Distributions ◽  
Textural Properties ◽  
Size Distributions ◽  
Particle Size Distributions ◽  
Normal Probability ◽  
Log Normal ◽  
Steep Slopes

ABSTRACTThe textural properties of many sediments provide a good indication of their provenance, but surprisingly little information is available on the transitional stages between the breakdown of a rock and the incorporation of the material into a fluvial sediment. These transitional stages are important as certain fractions (particularly the finer ones) may be selectively removed. Regoliths developed on steep slopes represent an early stage in the debris cascade and they are here examined in detail to assess the role of parent lithology on the textural properties of the regolith. There are substantial variations between lithologies, although the majority of regoliths are dominated by coarser fractions and are poorly sorted. Most particle size distributions show some degree of fit to both log-normal probability distributions and Rosin distributions. Differences from these can be ascribed to the processes operating on steep slopes, particularly the influx of sand- and silt-sized material by colluvial processes and the removal of clay-sized material by leaching. The regoliths form a distinct facies type which may be recognisable in the geological record.

scholarly journals Eliminace mikropolutantů z vod kombinací oxidačních a sorpčních procesů v laboratorním měřítku

Entecho ◽  
2021 ◽  
Vol 4 (1) ◽  
pp. 15-20
Author(s):  
Tamara Pacholská ◽  
Ivan Karpíšek ◽  
Jana Zuzáková ◽  
Vojtěch Kužel ◽  
Stanislav Gajdoš ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Wastewater Treatment Plants ◽  
Granular Activated Carbon ◽  
Pilot Scale ◽  
Post Treatment ◽  
Operational Parameters ◽  
Activated Carbon Adsorption ◽  
Boron Doped Diamond ◽  
Carbon Adsorption ◽  
Wwtp Effluent

Mikropolutanty v životním prostředí působí negativně na vodní ekosystémy a též představují potenciální riziko pro lidské zdraví. Zásadním zdrojem vnosu mikropolutantů do životního prostředí jsou městské ČOV, jejichž konvenční mechanicko-biologická technologie není na odstraňování mikropolutantů navržena. V této práci jsme testovali účinnost odstranění mikropolutantů řadou oxidačních (např. ozonizace, UV/H2O2, Fentonova reakce, borem dopovaná diamantová elektroda) a sorpčních (např. granulované aktivní uhlí GAU, zeolity) procesů. Účinnost odstranění vybraných léčiv (např. erythromycin, sulfamethoxazol, ibuprofen atd.) a metabolitů pesticidů (např. acetochlor ESA, metazachlor ESA) jsme testovali v jednorázových vsádkových testech. S přihlédnutím k ekonomickým i provozním parametrům byla pro následné testování v reálných podmínkách (poloprovozní měřítko) zvolena kombinace oxidace UV/H2O2 a sorpce na GAU. Mikropolutanty v modelové vodě byly úspěšně odstraněny z 91% (suma léčiv) a cca 100% (suma metabolitů pesticidů) při použití optimální dávky H2O2 5 mg/l a intenzity UV záření 4 kJ/m2 s následnou sorpcí na GAU. Tyto velmi slibné výsledky v současné době ověřujeme v pilotní jednotce pro dočištění reálného odtoku z městské ČOV. Abstract (EN) Micropollutants cause harm to aquatic ecosystems and can also negatively affect human health. Major sources of micropollutants input to aquatic environments are wastewater treatment plants due to their insufficient removal during the conventional mechanical-biological process. This study aimed to evaluate potential WWTP effluent post-treatment processes for the removal of selected pharmaceuticals and pesticides using oxidation (e.g., ozonization, UV/H2O2, Fenton, boron-doped diamond electrode) and sorption (e.g. granular activated carbon, zeolite) processes and their combinations. The removal of selected pharmaceuticals (e.g. erythromycin, sulphamethoxazole, ibuprofen) and pesticides (e.g. acetochlor ESA, metazachlor ESA) was tested in batch assays. The combination of UV/H2O2 and activated carbon adsorption was the most favorable in terms of removal efficiency and economic and operational parameters. This combination achieved the removal efficiencies of pharmaceuticals and pesticides of 91 and 100%, respectively, using an optimum H2O2 dose of 5 mg/L and UV intensity of 4 kJ/m2 followed by granular activated carbon adsorption. These promising results are currently adopted in a pilot-scale study for the post-treatment of a real WWTP effluent.

Exploring the role of chemo-mechanical technique on the properties of nanocellulose isolated from different varieties of rice bran

BioResources ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. 6965-6983
Author(s):  
Nurul Najihah Ilias ◽  
Norazatul Hanim M. Rozalli ◽  
Mohamad Haafiz M. Kassim
Keyword(s):  
Acid Hydrolysis ◽  
Rice Bran ◽  
Morphological Structure ◽  
Size Distributions ◽  
Particle Size Distributions ◽  
Agricultural Residue ◽  
Potential Source ◽  
Transmission Electron ◽  
Insight Into

Nanocellulose (NC) was isolated from an underutilized agricultural residue, defatted rice bran (DRB), obtained from three major paddy varieties in Malaysia, MARDI Rice (MR): MR 220, MR 219, and MR 297. The DRB was subjected to alkali (NaOH) and bleaching treatments prior to the isolation of NC. The NC from DRB was produced through the acid hydrolysis technique using 55%wt sulphuric acid (H2SO4) with the assistance of ultrasonication. The morphological structure of NC was analyzed through transmission electron microscopy (TEM). Based on the observation, a needle-like structure was observed for NC 219 while NC 220 and NC 297 showed nano-web structures. All obtained NC dimensions ranged from 183 to 263 nm long and 4.70 to 4.97 nm wide. Fourier transform infrared (FTIR) spectroscopy revealed the presence of all important compositions for the cellulose of each variety, indicating that the chemical structure of DRB cellulose has not been altered by acid hydrolysis. Particle size distributions portrayed a unimodal graph for NC 220 and NC 219. This comparative study provides an insight into the possibility of using DRB as a potential source of NC. The promising characteristics of NC from MR 219 allowed its application as an emulsifier for stabilizing a solid particle-based emulsion.

Influence of denitrification on suspended solids and phosphorus removal in multimedia filters

2006 ◽  
Vol 6 (1) ◽  
pp. 113-120
Author(s):  
V. Miska ◽  
J.H.J.M. van der Graaf ◽  
J. de Koning
Keyword(s):  
The Netherlands ◽  
Nutrient Removal ◽  
Phosphorus Removal ◽  
Suspended Solids ◽  
Wastewater Treatment Plants ◽  
Pilot Scale ◽  
Phosphate Removal ◽  
Treatment Technique ◽  
Wwtp Effluent ◽  
Removal Efficiencies

Due to more stringent WWTP-effluent requirements in The Netherlands, caused by adoption of the European legislation, the characteristics of WWTP-effluents need to be improved. For existing wastewater treatment plants extended nutrient removal will be required with final effluent concentrations of Ptot≤0.15 mg/L and Ntot≤2.2 mg/L. For suspended solids and phosphorus removal flocculation-filtration is used frequently as advanced treatment technique. Simultaneous denitrification would provide a tertiary treatment step for combined nutrient removal under the condition that simultaneous denitrification has no adverse effects on suspended solids and phosphate removal. Pilot-scale experiments have been carried out at the WWTP in Utrecht and lab-scale investigations at the WWTP in Beverwijk, both in the Netherlands. The removal efficiencies for phosphorus and suspended solids in multimedia filters, operated under optimal denitrifying conditions, had been evaluated by phosphorus analyses and particle counting. It is examined that denitrifying biomass has no negative effect on the removal efficiencies.

scholarly journals The Role of Particle Size in Producing the F- Coronal Scattered Brightness

1996 ◽  
Vol 150 ◽  
pp. 349-352
Author(s):  
R.M. MacQueen ◽  
W.C. Davidson ◽  
I. Mann
Keyword(s):  
Particle Size ◽  
Mie Theory ◽  
Interplanetary Dust ◽  
Dust Particles ◽  
Size Distributions ◽  
Particle Size Distributions ◽  
Interplanetary Dust Particles ◽  
Infrared Observations ◽  
Flux Measurements

AbstractMotivated by new infrared observations, we examine the contribution of various size intervals of interplanetary dust particles to visible and infrared scattered radiances of the solar F-corona, employing Mie theory and particle size distributions based upon differing interpretations of lunar microcrater evidence and interplanetary flux measurements.

Sign in / Sign up

Export Citation Format

Share Document