Zabel T Flotation in water treatment. In: Ives KJ ed The scientific basis of flotation. Martinus Nijhoff, The Hague, pp — Download references. Sudilovskiy, G. Kagramanov, A. You can also search for this author in PubMed Google Scholar.
Correspondence to G. Reprints and Permissions. Sudilovskiy, P. Use of membranes for heavy metal cationic wastewater treatment: flotation and membrane filtration. Clean Techn Environ Policy 9, — Download citation.
Received : 01 August Accepted : 12 January Published : 02 March Issue Date : August Anyone you share the following link with will be able to read this content:.
Download spreadsheet cooling. Most buzzwords in membrane filtration are explained. Download text definitions. Calculation about diafiltration volume, when the TDS is defined. Calculation about TDS when diafiltration volume is defined. Download spreadsheet diafiltration.
Various points of view about disinfection. Download text Disinfection. Calculation of kW when flow and pressure is known. Download spreadsheet energy. See front home page for new version. Practical tips and hints. No theory. Only practical observations. Download Handbook. Estimate osmotic pressure. Considering the membrane wall at the permeate side, our experimental work shows this phenomenon is true as lower water conductivities are observed at the bulk-phase.
Figure 3 shows the difference between the solute concentration near to the membrane wall and the bulk-solute concentration. It is obvious that as we go far away from the membrane surface, salt concentration decreases until we reach the bulk solute concentration, and this is attributed to concentration polarization phenomenon. Effect of applied pressure on the membrane performance has been investigated to obtain the optimal operating pressure for every studied membrane as well as the highest performance.
Water samples from the Red Sea water at Rabigh City have been taken as a feed in the experiment work for further investigations.
Major ion composition of collected seawater were similar to the composition of Red Sea at Jeddah which was reported elsewhere in a previous work and as shown in Table 5 Greenlee et al.
The experiment work included four commercial membranes that have been utilized to identify the ideal membrane type for the treatment of the Red Sea water.
The used commercial membranes physical properties and specs are shown in Tables 6 and 7 , respectively. The work was initiated by applying different pressure values on the used four commercial membranes FP, ES, AFC40 and AFC99 , as tabulated in Table 8 , in order to determine the optimal operating pressure for the treatment of the Red Sea water. Figure 4 shows a picture of the membrane filtration test unit Model: TR 14 that was used for the experiment work.
Procedure and desired operating conditions of each membrane type from Table 9 as well as the membrane filtration test unit process flow diagram from Fig. The feed tank Tank 1 water level was fixed with a level control to maintain the experimental work. Sensors and indicators including temperature transmitters, pressure indicators and flow transmitters were checked properly before starting the experiments to ensure correct results.
Open and closed valves plus valve connections have been investigated and applied for each membrane type experiment as described in Table 9. After that, the pump was operated to apply pressure on the membrane module at four different set points on each membrane, as shown in Table 8 , where the seawater was passed through each membrane type separately.
A pressure gauge was used to control the pressure increase from one experiment to the other. The system was operated for a short time 1—2 min in order to take the required water samples for further studies in which water samples were measured to determine the conductivity and pH values.
A sample of the tubular membrane used in the membrane filtration test unit is shown in Fig. Moreover, pH readings have been considered in the experimental results to study the relation between the different applied pressures and pH values pH is dependent on water conductivities since conductivities are attributed to applied pressure.
A comparison between the four membranes was established to select the ideal membrane at a specific operating pressure for the treatment. Equation 4 was used to calculate the exact removal percentage treatment efficiency of each membrane type from the water samples besides their initial and final conductivities Perry and Green The overall investigation concluded that as the applied pressure increased, the water conductivity decreased; which indicated an inverse correlation between pressure and conductivity.
Effect of different applied pressures on the treatment of the Red Sea water in membrane 1 FP Effect of different applied pressures on the treatment of the Red Sea water in membrane 2 ES Also, ES in Fig.
Contrary to what was expected, conductivity increased at 10 bar which might be attributed to accumulation of salts on ES membrane surface from the first experiment at 5 bar; and then the following experiments at 20 and 30 bars decreased conductivity again which might confirm our analysis.
Similar observations were recorded in Figs. In the four studied membranes, the water conductivity decreased sharply, initially, and then reached a plateau due to salt depositions onto membrane surface which restrained further salt rejections. Conductivity results were found as expected since RO membranes are commercially utilized to treat seawater and produce desalinated water by having the outlet water conductivities much less than the inlet conductivities. However, since CaCO 3 is slightly soluble in water, the pH of the water should be above 7 and therefore CaCO 3 could be responsible for the increase in the water basicity.
In all membranes, very slight changes in pH were noted and pH level decreased sharply at the first applied pressure experiment and then started to recover the initial pH level at further stages.
The initial decrease in pH levels was attributed to the rejections of CaCO 3 salts from seawater which decreases product water basicity. However, successive experiments at higher pressures may force accumulated CaCO 3 salts on the membrane surface to go through and recover pH level increase water basicity in later stages.
Figures 11 and 13 showed the pH behavior in FP and AFC40, respectively, which decreased initially with the applied pressure due to the removal of CaCO 3 and then recovered to a magnitude about the initial pH.
However, Figs. As noted previously, pH recovery occurred in further stages because of passing of accumulated CaCO 3 salts across the membrane when treating seawater at higher pressures.
The overall investigation concluded that there was a slight proportional relationship between pH and pressure taking into consideration that the initial sudden pH decrease in ES and AFC99 extended for the first two pressure experiments. To ease the calculations, the applied pressure that is related to the previous results was determined by taking the average of the four different applied pressure values of each membrane type.
Obviously, we have an inverse relationship between applied pressure and water conductivity. On the contrary, pH levels slightly decrease when decreasing the applied pressure; the variations of pH with pressure are very low and this could fall into the error percentage as shown in Figs. Yet, based on the energy demand, AFC40 should be operated at an applied pressure that is 4 bar less than AFC99 from the manual data as shown in Table 8 ; hence, AFC40 is the ideal membrane choice due to its lower energy demand.
During the process of impurities removal, membranes will inevitably encounter the membrane fouling induced by micro-particles and their combination with organic matters in seawater as shown in Fig. It can be noticed that we had various impurities with different particles size on the membrane surface which is respective to membrane pore size. This can be attributed to the large pores of the three membranes compared to AFC Despite that AFC40 and AFC99 are both with the same pore size RO membranes , contribution of the high-pressure operation on AFC99 might be responsible for the decomposition of large particles into smaller ones as shown in Fig.
The authors suggest that the yellowish color appeared in Fig. Seawater contains approximately 1—3 ppb of iron and most algae in seawater contain between 20 and ppm of iron, and some brown algae may accumulate up to ppm Murphy et al. Iron has a silver color, but when both water and oxygen are present iron corrodes and changes to a yellowish color due to the formed hydrated oxides. Also, a regular backwash with air scour should be conducted for UF membranes FP to remove foulants.
Estimated water flux has been calculated experimentally from the known membrane area, feed water volume and treatment time. Feed water fluxes varied between 4 and However, permeate water flux data were not available, but the authors believe that values of the permeate flux should be close to the feed flux depending on the membrane resistance to the coming flow.
Also, pH levels of produced water were analyzed to check the effect of different applied pressures on pH variations. The ultimate goal was to identify the ideal membrane type for the treatment of the Red Sea water among the four commercial membranes with its optimum pressure.
It is suggested that applying higher pressures would increase the treatment efficiency in the four commercial membranes. An inverse relationship was identified between water conductivity and applied pressure, and pH levels slightly decreased at high pressures.
Our findings confirmed that AFC40 is the ideal membrane choice among other commercial membranes for the treatment of the Red Sea water because of the high treatment efficiency of Desalination — Article Google Scholar. Desalination 96 1 — Water Supply 17 1 — Google Scholar. Charcosset C A review of membrane processes and renewable energies for desalination. Desalination 1—3 — Desalination 1 — Emis: energie-en milieu-informatiesysteem voor het Vlaamse Gewes Microfiltration.
EPA N Membrane filtration guidance manual. Fane AG Membranes for water production and wastewater reuse. Desalination 1 :1—9. Ultrafiltration and Microfiltration, Hudson.
Geankoplis C Transport processes and separation process principles includes unit operations. Prentice Hall Press, Englewood Cliffs.
0コメント