Direct capillary nanofiltration for ground water and surface water treatment

2002 ◽  
Vol 2 (5-6) ◽  
pp. 277-283 ◽  
Author(s):  
J.Q.J.C. Verberk ◽  
J. Post ◽  
W.G.J. van der Meer ◽  
J.C. van Dijk

Capillary nanofiltration is a new concept in membrane filtration. This technique combines the advantages of the good water quality obtained from nanofiltration membranes with the easy hydraulic cleaning of capillary membranes. Direct capillary nanofiltration can be used to treat ground water or surface water without pre-treatment. At the Delft University of Technology several MSc-thesis projects have been carried out on this subject. This paper will describe some results of these studies. A model based on a mass balance to predict the flux of a capillary nanofiltration installation treating groundwater is proposed. In this model the only resistance taken into account is the concentration polarisation. Also a model to predict the flux when treating surface water has been developed. This model takes into account the resistance due to cake filtration.

2002 ◽  
Vol 46 (4-5) ◽  
pp. 257-264 ◽  
Author(s):  
A. Dietze ◽  
R. Gnirß ◽  
U. Wiesmann

Surface waters are often burdened with inflows of low quality water, so that drinking-water production, swimming or ground water charging must be restricted. To ensure the long-term use of such surface water it is necessary to treat the influents or the water used for ground water charging. The current treatment process for phosphorus and turbidity removal is a process combination called floc filtration. By using this conventional method it is possible to reduce the dissolved ortho-phosphate and the turbidity (particulate phosphorus) as well as the amounts of algae and pathogenic organisms to very low concentrations. The high degree of reduction is only achieved by a relatively high dosage of chemicals. A comparison will be made between this process, which represents the state-of-the-art, and the combination of precipitation/coagulation with micro-/ultrafiltration in dead-end filtration mode.


2003 ◽  
Vol 3 (5-6) ◽  
pp. 23-30 ◽  
Author(s):  
A. Dietze ◽  
U. Wiesmann ◽  
R. Gnirß

Surface water such as aquifers, recreational waters and rivers are often loaded by inflows with low quality, so that drinking water production, swimming or ground water charging must be restricted. To ensure the long-term use it is necessary to treat the influents or the water used for ground water charging. The current treatment process for phosphorus and turbidity removal is a combination of precipitation/coagulation, flocculation, sedimentation and sand filtration. By using this conventional method it is possible to reduce the dissolved ortho-phosphate and the turbidity (particulate phosphorus) as well as the amounts of algae and pathogenic organisms to very low concentrations. The high degree of reduction in this process is only achieved by a relatively high dosage of coagulants and flocculants. Such a process has been used for nearly 20 years by the Berliner Wasserbetriebe. In this study a comparison will be made between this process, which represents the state-of-the-art, and the combination of precipitation/coagulation with dead-end membrane filtration (micro-/ultrafiltration) concerning water quality and costs. The results show that it is possible to reach similar levels of phosphorus removal as with floc filtration. However, floc filtration requires significantly higher amounts of chemicals (coagulants and flocculants). No flocculants are used for membrane filtration. But the estimated costs for the membrane based process are at 0.17 €/m3 probably a little more expensive. However, the excellent permeate quality is much better at the values of suspended solids and micro-biological organisms.


2019 ◽  
Vol 136 (45) ◽  
pp. 48205 ◽  
Author(s):  
Gulsum Melike Urper‐Bayram ◽  
Burcu Sayinli ◽  
Reyhan Sengur‐Tasdemir ◽  
Turker Turken ◽  
Enise Pekgenc ◽  
...  

Membranes ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 238
Author(s):  
Fangshu Qu ◽  
Zhimeng Yang ◽  
Shanshan Gao ◽  
Huarong Yu ◽  
Junguo He ◽  
...  

To understand impacts of organic adhesion on membrane fouling, ultrafiltration (UF) membrane fouling by dissolved natural organic matter (NOM) was investigated in the presence of background cations (Na+ and Ca2+) at typical concentrations in surface water. Moreover, NOM adhesion on the UF membrane was investigated using atomic force microscopy (AFM) with colloidal probes and a quartz crystal microbalance with dissipation monitoring (QCM-D). The results indicated that the adhesion forces at the NOM-membrane interface increased in the presence of background cations, particularly Ca2+, and that the amount of adhered NOM increased due to reduced electrostatic repulsion. However, the membrane permeability was almost not affected by background cations in the pore blocking-dominated phase but was aggravated to some extent in the cake filtration-governed phase. More importantly, the irreversible NOM fouling was not correlated with the amount of adhered NOM. The assumption for membrane autopsies is doubtful that retained or adsorbed organic materials are necessarily a primary cause of membrane fouling, particularly the irreversible fouling.


2005 ◽  
Vol 51 (6-7) ◽  
pp. 221-229 ◽  
Author(s):  
A. Lerch ◽  
S. Panglisch ◽  
R. Gimbel

Recently, new concepts for direct or pre-treatment minimised processes for the treatment of surface waters to potable water have aroused more and more interest. The requirements of such concepts are various and express the desire for high flexibility, adaptation on various water qualities and expandability of the treatment process. These requirements can be nearly ideally achieved by membrane technology. This publication presents the actual approach in research, piloting and operation of selective plants, research institutions and universities for the hybrid process coagulation/ultrafiltration (UF), or microfiltration (MF) respectively. The focus is set on the discussion of the influences of the mass freight, coagulation conditions, temperature and theoretical considerations about the coating layer build-up in dead-end and IN/OUT-mode driven MF and UF capillary membranes with a coagulation step prior to membrane filtration.


2017 ◽  
Vol 76 (2) ◽  
pp. 490-500 ◽  
Author(s):  
Yufei Wang ◽  
Hui Jia ◽  
Hongwei Zhang ◽  
Jie Wang ◽  
Wenjin Liu

A recycling magnetic flocculation membrane filtration (RMFMF) process integrating circulating coagulation, magnetic enhanced flocculation and membrane filtration was investigated for the treatment of surface water micro-polluted by tetracycline, a typical pharmaceutical and personal care product. A bench-scale experiment was conducted and several water quality parameters including turbidity, ultraviolet absorbance at 254 nm (UV254), total organic carbon and tetracycline concentration were evaluated, taking coagulation membrane filtration and magnetic flocculation membrane filtration processes as reference treatments. The experimental results showed that at the optimum doses of 20 mg·L−1 ferric chloride (FeCl3), 4 mg·L−1 magnetite (Fe3O4) and 6 mg·L−1 reclaimed magnetic flocs in RMFMF processes, removal efficiencies of above evaluated parameters ranged from 55.8% to 92.9%, which performed best. Simultaneously, the largest average particle size of 484.71 μm and the highest fractal dimension of 1.37 of flocs were achieved, which did not only present the best coagulation effect helpful in enhancing the performance of removing multiple contaminants, but also lead to the generation of loose and porous cake layers favouring reduced permeate flux decline and membrane fouling.


2017 ◽  
Author(s):  
Juan Pablo Gutiérrez ◽  
Doris van Halem ◽  
Luuk Rietveld

Abstract. The poor water quality of many Colombian surface waters, forces for seeking alternative, sustainable treatment solutions with the ability to manage peak pollution events and to guarantee an uninterrupted provision of safe drinking water to the population. This review assesses the potential of using riverbank filtration (RBF) for the highly turbid waters in Colombia emphasizing on water quality improvement and the influence of clogging by suspended solids. The suspended sediments may on the one hand be favorable in the improvement of the water quality mainly due to the strengthening of cake filtration and deep bed filtration processes. On the other hand, the formed cake layer must be balanced by scouring in order for an RBF system to be sustainable without loss of hydraulic capacity. In general, RBF seems to be a technology appropriate for use in highly turbid and contaminated surface rivers in Colombia, where improvements due to the removal of turbidity, and pathogens, and to a lesser extent inorganics, organic matter and micro-pollutants are expected. RBF has the potential to mitigate shock loads thus leading to the prevention of shutdowns of surface water treatment plants. In addition, RBF, as an alternative pre-treatment step, may provide an important reduction of chemicals’ consumption, considerably simplifying the operation of the existing treatment processes. However, clogging and self-cleansing issues must be studied deeper in the context of these highly turbid waters, evaluating the potential loss of abstraction capacity yield as well as the development of different redox zones for efficient contaminant removal.


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