Abstract: The issue of potable water in the poorest region of the world has never been a conceptual issue only but a financial and technical issue as well. This study aimed at evaluating the efficiency of four polymeric membranes by predicting their performance in terms of particle separation, permeability and mechanical strength. These membranes are to be placed in the purification section of a Water Filtration System (WFS) to obtain pure or non-turbid water for human consumption. This study introduced a microfiltration set-up connected to a solar power system as the beacon of hope for poorest regions of the world in order to eradicate the limited access to potable water

Belaid, Mohammed

Empompo, Jonathan Bambokela

Matheri, Anthony Njuguna

Muzenda, Edison

University of Johannesburg Institutional Repository

      ________________________________________________________________________________________                              2nd International Engineering Conference (IEC 2017)  Federal University of Technology, Minna, Nigeria Evaluation of Polymeric Membranes Efficacy For the Water Filtration System Prototype  Jonathan Bambokela Empompo2*, Edison Muzenda1,2, Mohammed Belaid2  and Anthony Njuguna Matheri2 1  Department of Chemical, Materials and Metallurgical Engineering, College of Engineering and Technology, Botswana International University of Science and Technology, Palapye.  2  Department of Chemical Engineering Technology, Faculty of Engineering and the Built Environment, University of Johannesburg, Doornfontein, Johannesburg, South Africa. *Corresponding Author: E-mail: jonathanbambokela@gmail.com  ABSTRACT The issue of potable water in the poorest region of the world has never been a conceptual issue only but a financial and technical issue as well. This study aimed at evaluating the efficiency of four polymeric membranes by predicting their performance in terms of particle separation, permeability and mechanical strength. These membranes are to be placed in the purification section of a Water Filtration System (WFS) to obtain pure or non-turbid water for human consumption. This study introduced a microfiltration set-up connected to a solar power system as the beacon of hope for poorest regions of the world in order to eradicate the limited access to potable water.  Keywords: efficiency, filtration, membranes, permeability, solar energy, wastewater. 1. INTRODUCTION  A) Water Availability The access to pure water in poorest regions has always been a technical and financial issue. The availability of potable water for human consumption has been limited by the lack of efficient wastewater treatment infrastructures, lack of education and awareness of the population, and inefficient governmental pollution control. The existing wastewater treatment facilities are observed to face several challenges relating to poor or critical conditions [1]. In many regions, the distribution of water has become inadequate and incapable to meet domestic, economic development and sanitation needs [2]. In one hand, the issues of water mismanagement and sanitation have caused the community to become more anxious on present factors due to the huge demand of water quality and quantity. On the other hand, the low financial implication of African governments in the improvements of current facilities and implementations of newly and efficient wastewater treatment technologies has become a major constraint on potable water availability. The increasing population, fast-infrastructural growth, river water quality and ecosystem deterioration due to pollution are red light signals to consider bringing about a total change in our world today [1, 2].   Adewumi et. al., [1] has reported that considerable strategies and efforts were being made by many African countries such as South Africa to remediate at all levels the problems of drinking water pollution and waste discharge in river streams. This urge for change has led the Department of Water Affairs and Environment (DWAE) to implement the Green Drop Certification Process to help the South African government to eradicate different issues linked to the non-compliance of municipal wastewater treatment service providers. Although the reuse of wastewater is still unconventional in many scarce regions of the world today, various separation and purification technologies have facilitated the reuse of wastewater from dissimilar sources [3]. Membrane separation processes such as microfiltration, ultrafiltration, nanofiltration, microfluidic techniques and reverse osmosis provide considerable solutions for water purification [3, 4]. Among these various membranes separation processes, microfiltration has been widely adopted in the water purification industry. It is reported that microfiltration can operate with lesser energy consumption than conventional thermal separation processes [4]. The low energy consumption, cost-effectiveness and high efficiency of microfiltration have attracted high interest over the years. Consequently, this drive has led to diverse investigations to improve the energy consumption of water treatment and make this separation and purification techniques affordable to every community.  B) Solar Energy As a substantial resource, energy plays a crucial role in the socioeconomic development of a country. Electricity, for instance, has particularly shown its dependence on cost affordability and subsequently on the economic vitality. For this cause, several studies have been conducted in order to implement natural sources of energy such as solar energy       ________________________________________________________________________________________                              2nd International Engineering Conference (IEC 2017)  Federal University of Technology, Minna, Nigeria to tackle tresholds caused by present energy systems [5, 6],  in spite of efforts made by scientists like Broman who pioneered the concept of solar energy and technology which is not as effective as it should be today [7, 8].  The adoption of renewable energy has facilitated the implementation of many potential technologies to bring a definite environmental change to make the world a better place to live. Over the last decade, the world has witnessed a tremendous change from the worldwide Green Campaign. Among many sources of renewable energy, solar energy has undeniably expanded over the region where power was in high demand. This expansion is slowly eradicating the issue of power from the poorest regions of the world. It has been proven from an economic point of view that generating power from sunlight is one of the cheapest and very effective technology today [9]. For instance, when looking at the 200 Megawatt (MW) project conducted in Dubai in 2015 which profitably aimed at selling electricity for $ 0.0584 per kilowatt-hour (Kwh), it can be understood that solar energy has many economic benefits revolving around the population’s welfare and country’s development [9]. Social benefits of solar energy delineated in the early 1990’s by Scheer [10-11], included the reduction of administrative costs to control and monitor damage due to conventional energy generation plants and the increase of job creations in European countries such as Germany where solar energy was among the renewable energy technologies which doubled the employment rate between 2004 and 2009 [11].  In light of these aforementioned facts, solar energy has been selected as the complementary source of power of this prototype which focuses essentially on water filtration.  2. THE WATER FILTRATION SYSTEM (WFS)                           Figure 1: Process Flow Diagram of the Water Filtration System The WFS as per figure 1, a prototype which incorporates two technologies: Renewable energy with solar power and water treatment by microfiltration membranes. It is mainly divided into three sections which are the feedstock section, the purification section and the conservation section known as the “Reservoir” as illustrated in figure 2.         Figure 2: Schematic representation of the Water Filtration System  Where: 1. Solar Panel           2. Solar Battery 3. Tank 1                  4. Solar pump 5. Water Pipe            6. Valve 1 7. Microfilter Tank   8. Valve  2 9. Valve 3                 10. Tank 2 (Reservoir) 11. Tank Stand 1       12. Tank Stand 2            FFFiltration Section  FFFeedstock Section FFWater conservation Section                 1                                                             7                                                                                                 6    8                       9 2 10  3                                  5             11                                                                                                                                        12                                          4                                ________________________________________________________________________________________                              2nd International Engineering Conference (IEC 2017)  Federal University of Technology, Minna, Nigeria As shown in figs. 1 and 2, turbid water is introduced as feedstock in tank 1 which is the first section of the system, and with the aid of a solar water pump, water is propelled to the second section where it is treated by means of a set of membranes. The pure water is transferred to the third section where it is conserved for human consumption. Many benefits can be deducted from the WFS. The use of a solar pump makes it environmentally friendly with no carbon dioxide emissions with a low energy consumption to transfer unclean water to a set of membranes which filter the feedstock and to section 3 where the final product is conserved.  3. METHODOLOGY The purpose of this study was to evaluate the efficiency of four polymeric membranes by the prediction of their performance in terms of particle separation, permeability and mechanical strength .  3.1. MATERIALS AND EQUIPMENTS The apparatus used in this experiment was mainly composed of  : a pump placed within the feedstock bucket of a capacity of 1000 ml, pipes, two valves and a set of four membranes diversely placed inside a 650 ml tank filled. Each membrane was connected to a pipe from which purified water was collected. In other words, when turbid water crossed the pores of membranes, the calcium remained on the frame and cleaned water was collected from inside out.   Figure 3: Membranes set-up  As shown in fig.3, membranes modules are mainly composed of plate and frame configurations where the plate is asymmetric with a thin skin supporter on a thicker layer with larger pores whereby dilute solutions are filtered.  Figure 4: Membranes set-up in the container   Figure 5: Pipe connection 3.2. EXPERIMENTAL PROCEDURE A quantity of 750g of Calcium was mixed with 1000 ml of water in the feedstock bucket to increase its turbidity.The pump was switched on, one valve was halfly open and the other was completely closed to avoid the overflow of the mixture inside the tank.  A syringe was used to facilitate the flow of water in membrane fibres and avoid filter cake.The process was run continuously for 3 days during specific hours and samples were collected from various membranes after certain hours for turbidity testing during a chronometric time. The apparatus was switched off and switched on the following day after daily experimental assessment.  Set of membranes Pipe through which water is collected after filtration   Pipe used for water collection after filtration Container whereby the turbid water is kept after coming from the bucket     Canal through which water from the bucket is sent to the container Membranes set-up: turbid water is filtered then collected from the pipe        ________________________________________________________________________________________                              2nd International Engineering Conference (IEC 2017)  Federal University of Technology, Minna, Nigeria 4. RESULTS AND DISCUSSIONS The experiment evaluated the efficiency of membranes from different flux values.  Flux is defined as the flow of a substance per unit area. In other words, the quantity of a substance which passes through a specific area in the space of time. As demonstrated in equation 1, flux is directly proportional to time and quantity but inversely proportional to area.               𝑗 =𝑞×𝑡𝐴                (1) Where: j: Flux (l.s/cm2) q: Quantity (l) A : Area (cm2) t:  Time (s)                   𝐴 = 𝑤×𝑙                             (2) Where : w: width l: length In table 1, different flux values were calculated as per equation 1. The area was determined from equation 2 knowing that the membrane’s width is 18 cm  and the length is 32 cm. Table 1. Flux and Time Data TIME (hours) M1 M2 M3 M4 0 17.23 17.27 17.816 26.328 2 16.38 16.014 18.149 23.544 4 12.84 14.047 15.664 22.169 17 11.21 1.0675 10.390 17.318 21 10.55 1.0575 10.210 17.957 40 4.583 1.0438 6.72 15.040  Where: M1: First membrane                      M3: Third membrane M2: Second membrane                  M4 :  Fourth membrane  Figure 6: Graphical representation of flux changes per hours In equation 1, flux calculation is  shown by a demonstration of the relation between the quantity of water collected from the pipe, the specific time-frame in which it is collected and the specific area through which water passed through before filling the membrane and be collected at end. This makes us understand the relationship between these factors and their impact in the result obtained in table 1 and fig.6. In table 1 and fig. 6, it can be seen that the flux decreased as the operating time increased. This can be justified by the fact that the quantity of water decreased with time by subsequently causing the flux to decrease as well. The direct proportionality of q and j was proven in this study  by the results obtained from four membranes as per table 1. Fig.6 shows similar trends of the four membranes. It can be seen that M4 had the highest flux values compare to M1, M2 and M3. This difference justifies the higher permeability of M4 or reveals anomalies of M4 causing water to circulate more abundantly with contaminants due to inefficient filtration.  From literature it is explained that several factors play crucial role in the efficiency of membrane filtration. These factors are fabrication materials, permeability, pores sizes (porosity) and  fouling[11, 12 ]. In a study conducted by Bukhari et. Al [11], it was explained that the ceramics membranes were increasingly attracting high attention due to their harsh environments resistance, chemical and thermal stability, high permeability with better control over pore-size distribution. It was also stated that certain membranes deprived of good permeability characteristics with insufficient mechanical 0510152025300 2 4 1 7 2 1 4 0FLUXHOURS  M1M2M3M4      ________________________________________________________________________________________                              2nd International Engineering Conference (IEC 2017)  Federal University of Technology, Minna, Nigeria strength to resist membrane pressure will be inefficient on the basis that fabrication  characterisitics pertaining the permeability are not effective. The permeability which is an important factor in the determination of membrane efficiciency, is totally dependent on the material of fabrication. As such, it can be understood that the material of fabrication (polymeric membrane) used in this study had a lower permeability as the flux values were very low and constantly decreased in the space of time. The porosity of a membrane plays one of the utmost role in water filtration [12, 13]. It affects the permeability and determine the impact of fouling on the flux. In this study, it was seen that fouling afftected the flux of water. This impact was apprehended from the results obtained in table 1. Although, particle separation occurred, and water was collected from membranes at different values, this study showed that the polymeric membrane used in this study will not be suitable for the WFS on the basis that membranes characteristics influencing flux, which is a key factor in microfiltration, will not be effective to generate a considerable amount of potable water to meet large communities daily needs. 5. CONCLUSION AND RECOMMENDATIONS The purpose of this experiment was to evaluate the efficiency of membranes from different flux values in order to predict their performance in the WFS. In this study, the permeability and effectiveness of four polymeric membranes was assessed by means of particles separation  to obtain  potable water for human consumption. It was proven that the polymeric membranes used in this study will not perform effectively in the prospective WFS due to their incapabilities to resist harsh environments, low mechanical strength and permeability. This study only focused on a specific aspect of microfiltration and suggest that further studies be conducted on the suitability of membranes for the WFS. Further studies should be conducted on ceramic, nylon and polyvinylidene fluoride membranes in terms of permeability and mechanical strength. More analytical studies shoud be performed on initial  and final water composition in order to assess the elimination of impurities such as pathogens, bacteria, cysts, and viruses in water. ACKNOWLEDGEMENTS The authors wish to thank the University of Johannesburg (UJ) and the Process, Energy and Environmental Technology Station (PEETS) funded by the Technology Innovation Agency (TIA) for allowing us to conduct experiments in their laboratory premises.  REFERENCES  1. Adewumi, J.R. and Olanrewaju, O.O., 2011. Green Drop Certification of wastewater treatment plants in South Africa-an initiative to reduce drinking water sources pollution and bedrock of wastewater reuse. African Journal of Science, Technology, Innovation and Development, 3(4), pp.65-81. 2. Cosgrove, W.J. and Loucks, D.P., 2015. Water management: Current and future challenges and research directions. Water Resources Research, 51(6), pp.4823-4839. 3. Dijkshoorn, J.P., Schutyser, M.A.I., Wagterveld, R.M., Schroën, C.G.P.H. and Boom, R.M., 2017. A comparison of microfiltration and inertia-based microfluidics for large scale suspension separation. Separation and Purification Technology, 173, pp.86-92. 4. Wang, Z., Crandall, C., Sahadevan, R., Menkhaus, T.J. and Fong, H., 2017. Microfiltration performance of electrospun nanofiber membranes with varied fiber diameters and different membrane porosities and thicknesses. Polymer, 114, pp.64-72. 5. Smil V. Energy Transitions: History, Requirements, Prospects. Westport, CT:Praeger Publishers; 2010. 6. Karanfil F, Li Y. Electricity consumption and economic growth: exploring panel-specific differences. Energy Policy 2015;82:264–77. 7. Lars Broman. Solar energy education — an important part of worldwide solar energy activities. In: Proceedings of the 2nd World Renewable Energy Congress.Pergamon Press, London; 1992. 8.  Beetz B. First Solar selected for 200 MW PV project in Dubai, 〈pv-magazine.com〉 [15.08.17]. 9.  Scheer H. Solar energy's economic and social benefits. Sol Energy Mater Sol C1995;38:555–68. 10. Ciriminna, R., Meneguzzo, F., Pecoraino, M. and Pagliaro, M., 2016. Rethinking solar energy education on the dawn of the solar economy. Renewable and Sustainable Energy Reviews, 63, pp.13-18. 11.  Bukhari, S.Z.A., Ha, J.H., Lee, J. and Song, I.H., 2017. Fabrication and optimization of a clay-bonded SiC flat tubular membrane support for microfiltration applications. Ceramics International, 43(10), pp.7736-7742. 12. Field, R.W. and Wu, J.J., 2011. Modelling of permeability loss in membrane filtration: Re-examination of fundamental fouling equations and their link to critical flux. Desalination, 283, pp.68-74. 13. Das, B., Chakrabarty, B. and Barkakati, P., 2016. Preparation and characterization of novel ceramic membranes for micro-filtration applications. Ceramics International, 42(13), pp.14326-14333.  

Evaluation of polymeric membranes efficacy for the water filtration system prototype

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Evaluation of polymeric membranes efficacy for the water filtration system prototype

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