Coagulation-Direct Filtration of Soft, Low Alkalinity Humic Waters

1999 ◽  
Vol 40 (9) ◽  
pp. 55-62 ◽  
Author(s):  
Bjørnar Eikebrokk
Keyword(s):  
Natural Organic Matter ◽  
Pilot Scale ◽  
Quality Parameters ◽  
Efficient Removal ◽  
Direct Filtration ◽  
Ph Values ◽  
Optimum Ph ◽  
Calcium Sources ◽  
Ph Conditions ◽  
Removal Efficiencies

Optimisation of coagulation-direct filtration processes with respect to efficient removal of humic substances, i.e. natural organic matter (NOM) has gained a lot of focus in many countries over the last years. This paper presents experimental results from pilot scale research studies aimed at optimising the coagulation-direct filtration process applied to soft and humic raw waters with low turbidity and alkalinity levels. Comprehensive tests of 3 types of raw waters with different NOM content, 5 types of coagulants, and 3 calcium sources for the purpose of corrosion control have been conducted. Removal efficiencies with respect to relevant water quality parameters are presented, with typical relationships between raw water NOM content, coagulant dose requirements and pH. Generally, when applying metal-based coagulants, residual metal concentration was the critical parameter regarding minimum coagulant dose requirements. Typical NOM removal efficiencies were in the range of 75-90% and 40-70% with respect to colour and organic carbon, respectively. Optimum pH conditions for the removal of NOM and/or residual metals do not always coincide with that of turbidity. The experiments also showed that poly-aluminium and ferric chlorides might have some benefits over alum in terms of dose requirements and range of optimum pH values, and that chitosan may be used for colour removal with good results.

Electrical and optical properties of well-dispersed MWCNTs/PVA nanocomposites under different pH conditions

2018 ◽  
Vol 32 (4) ◽  
pp. 442-453 ◽  
Author(s):  
Emad AM Farrag ◽  
Rami A Abdel-Rahem ◽  
SS Ibrahim ◽  
Ayman S Ayesh
Keyword(s):  
Room Temperature ◽  
Ph Value ◽  
Poly Vinyl Alcohol ◽  
Electrical And Optical Properties ◽  
Multiwalled Carbon ◽  
Casting Technique ◽  
Ph Values ◽  
Current Voltage ◽  
Optimum Ph ◽  
Ph Conditions

Series of polymer nanocomposites films consisting of pretreated multiwalled carbon nanotubes (PT-MWCNTs) and poly (vinyl alcohol) (PVA) were prepared at room temperature. The MWCNTs were initially pretreated with 1.0 M sulfuric acid (PT-MWCNTs) and then allowed to disperse in aqueous solutions at different pH values (2–14). It was found that the dispersion of the PT-MWCNTs is a pH dependent. The best PT-MWCNTs dispersion was obtained at pH = 10. Films of PT-MWCNTs/PVA, at this optimum pH-value, were then prepared by casting technique at different PT-MWCNTs weight fractions. The resulted PT-MWCNTs/PVA films were characterized through the direct visualization, Fourier transform infrared, and morphology test. Besides, current–voltage and direct current electrical conductivity for PT-MWCNTs/PVA nanocomposites at 60°C showed that the conductivity mechanism was ohmic and the percolation threshold was around 0.8 wt% PT-MWCNTs. Optical results showed that PT-MWCNTs are homogeneously distributed in the neat PVA and optical gap is significantly decreased from 4.40 to 2.96 eV.

On the metabolism of Aspergillus terreus on ammonium nitrate at different pH values

1972 ◽  
Vol 50 (11) ◽  
pp. 2211-2218 ◽  
Author(s):  
Kaiser Naguib ◽  
A. Elbaz Younis ◽  
A. A. Elessawy
Keyword(s):  
Ammonium Nitrate ◽  
Aspergillus Terreus ◽  
Ammonium Nitrogen ◽  
Soluble Nitrogen ◽  
Nitrogen Absorption ◽  
Sugar Absorption ◽  
Ph Values ◽  
Optimum Ph ◽  
Ph Conditions ◽  
Ph Range

One-week-old fungal mats of Aspergillus terreus Thom were fed with buffered Dox's liquid medium containing ammonium nitrate as nitrogen source and adjusted to six different pH values, namely, 3.0, 3.8, 5.4, 6.8, 8.4, and 10.0. Ammonium nitrogen and nitrate nitrogen absorption and utilization, sugar absorption, respiration, and growth were followed over a period of 72 h at 24-h intervals.Ammonium and nitrate were absorbed at all pH values tested, nitrate being preferentially absorbed at the lower, but ammonium at the higher pH values. Low absorption and utilization of nitrogen occurred at the lowest and highest pH values. Optimum pH for sugar absorption was that for nitrogen absorption, though the former was more sensitive to change of pH than the latter. Rate of respiration was affected by sugar and nitrogen absorption. It was optimum at the same optimum for these two processes.There was release of nitrogen from the mycelial cells to the external medium at all pH values tested, but highest release occurred under different pH conditions and was independent of whether ammonium or nitrate absorption was prevailing.In the fungal mats, more soluble nitrogen and less protein were found at the lowest and highest pH values, while less soluble nitrogen and more protein were found at the optimum pH range; a difference apparently more related to pH than to whether ammonium or nitrate was being absorbed.

Effects of incubation fluid pH and fibrolytic enzymes on the in vitro fermentation of pure substrates, assessed using the Reading Pressure Technique (RPT)

2002 ◽  
Vol 2002 ◽  
pp. 208-208 ◽  
Author(s):  
D. Colombatto ◽  
F. L. Mould ◽  
M. K. Bhat ◽  
E. Owen
Keyword(s):  
In Vitro Fermentation ◽  
Commercial Enzyme ◽  
Fibrolytic Enzymes ◽  
Optimum Activity ◽  
Ph Values ◽  
Optimum Ph ◽  
Ph Conditions ◽  
Ph Range ◽  
Optimum Ph Range

Modern feeding practices often lead to ruminal conditions being sub-optimal for fibre digestion. It has been speculated that fibrolytic enzymes, which usually show optimum activity at pH values below 6.0, may be of benefit when applied to diets of high producing animals. This study used a commercial enzyme mixture (EM), already identified as effective; to investigate its optimum pH range with respect to activity and its impact on the fermentation profiles of pure substrates, under differing pH conditions.

Investigation of Some Water Quality Parameters of Pond Water under Mymensingh Municipality

2015 ◽  
Vol 8 (1) ◽  
pp. 85-89
Author(s):  
F Zannat ◽  
MA Ali ◽  
MA Sattar
Keyword(s):  
Water Quality ◽  
Water Samples ◽  
Chemical Properties ◽  
Pond Water ◽  
Quality Parameters ◽  
Water Quality Parameters ◽  
Urban Region ◽  
Mn Toxicity ◽  
Ph Values ◽  
Drinking Water Standard

A study was conducted to evaluate the water quality parameters of pond water at Mymensingh Urban region. The water samples were collected from 30 ponds located at Mymensingh Urban Region during August to October 2010. The chemical analyses of water samples included pH, EC, Na, K, Ca, S, Mn and As were done by standard methods. The chemical properties in pond water were found pH 6.68 to 7.14, EC 227 to 700 ?Scm-1, Na 15.57 to 36.00 ppm, K 3.83 to 16.16 ppm, Ca 2.01 to 7.29 ppm, S 1.61 to 4.67 ppm, Mn 0.33 to 0.684 ppm and As 0.0011 to 0.0059 ppm. The pH values of water samples revealed that water samples were acidic to slightly alkaline in nature. The EC value revealed that water samples were medium salinity except one sample and also good for irrigation. According to drinking water standard Mn toxicity was detected in pond water. Considering Na, Ca and S ions pond water was safe for irrigation and aquaculture. In case of K ion, all the samples were suitable for irrigation but unsuitable for aquaculture.J. Environ. Sci. & Natural Resources, 8(1): 85-89 2015

Pilot Scale Testing of a New Radium-226 Removal Process

1985 ◽  
Vol 20 (2) ◽  
pp. 55-67
Author(s):  
W.B. Anderson ◽  
P.M. Huck ◽  
T.M.R. Meadley ◽  
T.P. Hynes
Keyword(s):  
Treatment Process ◽  
No Reduction ◽  
High Surface ◽  
High Surface Area ◽  
Barium Chloride ◽  
Pilot Scale ◽  
Activity Levels ◽  
New Process ◽  
Removal Efficiencies ◽  
New Treatment

Abstract This paper describes the on-going pilot scale development of a new treatment process designed to remove radium-226 from uranium milling effluents. Presently, decants from Canadian uranium mining and milling tailings areas are treated with barium chloride to remove radium-226 prior to discharge into the environment. This is usually accomplished in large natural or man-made ponds which provide an opportunity for a (Ba,Ra)SO4 precipitate to form and subsequently settle. Sand filtration is sometimes used as a polishing step. This new process differs from conventional and other experimental processes in that it involves the use of a fluidized bed to facilitate the deposition of a (Ba,Ra)SO4 precipitate on a granular medium of high surface area. As a stand-alone treatment process, the new process is consistently able to reduce incoming radium-226 activity levels by 90-99%. Effluent levels of 10 pCi/L (0.370 Bq/L) or less have been achieved, depending on the influent activity levels. Recent testing of the process as a polishing step has demonstrated radium removal efficiencies up to 60% when the process influent was already less than 5 pCi/L (0.185 Bq/L). The process has been operated at temperatures ranging from 26°C down to 0.3°C with no reduction in efficiency. In contrast to treatment times in the order of days for conventional settling pond systems and hours for mechanical stirred tank/filtration systems, the new process is able to achieve these radium removal efficiencies in times on the order of one minute.

Trans-sialidase Associated with Atherosclerosis: Defining the Identity of a Key Enzyme Involved in the Pathology

2019 ◽  
Vol 20 (9) ◽  
pp. 938-941
Author(s):  
Victor Y. Glanz ◽  
Veronika A. Myasoedova ◽  
Andrey V. Grechko ◽  
Alexander N. Orekhov
Keyword(s):  
Acid Metabolism ◽  
Research Subject ◽  
Disease Pathogenesis ◽  
Sialidase Activity ◽  
Ph Values ◽  
Ldl Particles ◽  
Optimum Ph ◽  
Key Enzyme ◽  
St6gal I

Atherosclerosis is associated with the increased trans-sialidase activity, which can be detected in the blood plasma of atherosclerosis patients. The likely involvement in the disease pathogenesis made this activity an interesting research subject and the enzyme that may perform such activity was isolated and characterized in terms of substrate specificity and enzymatic properties. It was found that the enzyme has distinct optimum pH values, and its activity was enhanced by the presence of Ca2+ ions. Most importantly, the enzyme was able to cause atherogenic modification of lowdensity lipoprotein (LDL) particles in vitro. However, the identity of the discovered enzyme remained to be defined. Currently, sialyltransferases, mainly ST6Gal I, are regarded as major contributors to sialic acid metabolism in human blood. In this mini-review, we discuss the possibility that atherosclerosis- associated trans-sialidase does, in fact, belong to the sialyltransferases family.

scholarly journals Critical importance of pH and collector type on the flotation of sphalerite and galena from a low-grade lead–zinc ore

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Abdolrahim Foroutan ◽  
Majid Abbas Zadeh Haji Abadi ◽  
Yaser Kianinia ◽  
Mahdi Ghadiri
Keyword(s):  
Iron Ore ◽  
Low Grade ◽  
Zinc Recovery ◽  
Flotation Process ◽  
Ph Values ◽  
Lead And Zinc ◽  
Optimum Ph ◽  
Iron And Zinc ◽  
Lead Zinc ◽  
Zinc Concentrate

AbstractCollector type and pulp pH play an important role in the lead–zinc ore flotation process. In the current study, the effect of pulp pH and the collector type parameters on the galena and sphalerite flotation from a complex lead–zinc–iron ore was investigated. The ethyl xanthate and Aero 3418 collectors were used for lead flotation and Aero 3477 and amyl xanthate for zinc flotation. It was found that maximum lead grade could be achieved by using Aero 3418 as collector at pH 8. Also, iron and zinc recoveries and grades were increased in the lead concentrate at lower pH which caused zinc recovery reduction in the zinc concentrate and decrease the lead grade concentrate. Furthermore, the results showed that the maximum zinc grade and recovery of 42.9% and 76.7% were achieved at pH 6 in the presence of Aero 3477 as collector. For both collectors at pH 5, Zinc recovery was increased around 2–3%; however, the iron recovery was also increased at this pH which reduced the zinc concentrate quality. Finally, pH 8 and pH 6 were selected as optimum pH values for lead and zinc flotation circuits, respectively.

Pre-Ozonation-Coagulant Interactions in Direct Filtration

2010 ◽  
Vol 45 (3) ◽  
pp. 317-326 ◽  
Author(s):  
Murat Eyvaz ◽  
Hatice Deniz ◽  
Tuğrul S. Aktaş ◽  
Ebubekir Yüksel ◽  
Ahmet M. Saatçi
Keyword(s):  
Ferric Chloride ◽  
Aluminum Sulfate ◽  
Pilot Scale ◽  
The Other ◽  
Design Parameters ◽  
Dimensionless Number ◽  
Raw Water ◽  
Direct Filtration ◽  
Effluent Quality ◽  
Sulfate Application

Abstract Pre-ozonation–coagulant interactions effects in relation to the coagulant type and dosage in direct filtration of surface waters were investigated. The performance of the process was evaluated by monitoring the effluent quality and head loss development through the filter bed. Two identical pilot scale filter columns filtering the same raw water were operated in parallel. The raw water was brought from Ömerli Reservoir in Istanbul. Before filtering, the raw water flow was split into two equal flows. One of the streams was pre-ozonated and the other was aerated using contact chambers with equal volumes equipped with same number and type of diffusers. In coagulation experiments, one of the filters was operated using aluminum sulfate as a coagulant while the other one was run with ferric chloride. For similar filter run times, the effluent quality was always better with pre-ozonation compared to aeration. It was also observed that, aluminum sulfate application gave more favorable results for both particle and turbidity removal compared to ferric chloride. Ives’ filterability index which incorporates the important filtration design parameters such as: effluent quality, the headloss and the velocity of filtration into a dimensionless number was used for the comparison of the experimental results.

Sign in / Sign up

Export Citation Format

Share Document