Original Article Performance Evaluation of Tile Wastewater Treatment with Different Coagulants

Transcription

1 Journal of Environmental Health and Sustainable Development. 2016; 1(1) Original Article Performance Evaluation of Tile Wastewater Treatment with Different Coagulants Tahereh Zarei Mahmoud Abadi 1, Asghar Ebrahimi 2 *, Mohammad Taghi Ghaneian 3, Mehdi Mokhtari 2, Mohammad Hossein Salmani 4, Parvaneh Talebi 1 1 BSc, Environmental Science &Technology Research Center, Department of Environmental Health Engineering, School of Public Health, Shahid Sadoughi University of Medical Sciences,Yazd, Iran, taherehzarei92@gmail.com, apf_sts_1381@yahoo.com 2 Assistant Professor, Environmental Science &Technology Research Center, Department of Environmental Health Engineering, School of Public Health, Shahid Sadoughi University of Medical Sciences,Yazd, Iran, Mhimokhtari@gmail.com 3 Associate Prof. Environmental Science &Technology Research Center, Department of Environmental Health Engineering, School of Public Health, Shahid Sadoughi University of Medical Sciences,Yazd, Iran, mtghaneian@yahoo.com 4 Assistant Professor, Environmental Science &Technology Research Center, Department of Environmental Health Engineering, School of Public Health, Shahid Sadoughi University of Medical Sciences,Yazd, Iran, Mhsno6@yahoo.com Received: 18 Jan 2016 Accepted: 29 Feb 2016 Abstract Introduction: The objective of this study was, wastewater quality investigation and removal efficiency of contaminants from the wastewater tile factory by using coagulants includes ferric chloride, ferric sulfate and ferrous, aluminum sulfate and poly aluminum chloride in order to reuse it in the processing line. Methods: This is an applied study. With regard to shiftwork schedules of the factory, the composite samples of wasrewater in production line was obtained. Firstly, based on standard methods wastewater parameters were measured. In the next step by using the jar- test the effect of changing coagulants dosing(0.15, 0.2, 0.25, 0.3, 0.35g/L) and ph values (7,9,11) on the removal parameters of turbidity, EC, TSS, TS and COD was investigated. Finaly the effective dose and optimal ph were selected and the best coagulant was determined. Results:The optimum PH of ferric chloride, ferric sulfate and ferrous that optimum was 11as well as it was 7 for aluminum sulfate and poly aluminum chloride. The optimum concentration of iron-based coagulants and aluminumbased coagulants was 0.3 g/l and 0.25 g/l, respectively. Poly aluminum chloride with removal of 99.92%, 99.94%, 89.8 and 75% has the best removal efficiency for turbidity, TSS, TS and COD, respectively. In addition, in a lower dose aluminum sulfate, ferrous sulfate, ferric chloride and ferric sulfate had the best removal efficiency. Conclusion: Among the five studied coagulants, poly aluminum chloride, aluminum sulfate and ferrous sulfate had the most efficiency, respectively. Due to the high cost of aluminum chloride, it needs more accuracy to select the most suitable coagulant. Keywords: Coagulant, Wastewater treatment, Tile industry, Turbidity, COD *Corresponding author: Asghar Ebrahimi ebrahimi20007@gmail.com Tel:

2 Zarei Mahmoud Abadi Tahereh, et al. Introduction: In recent decades, the growth of consumption and increasing of industrial production was reflected in rapid decline of available natural resources (raw materials and energy resources). On the other hand, high quantity of waste generated in which most of them not directly recyclable (1). Water is used as an initial material in many industries and wastewater is discharged to the environment (2). In order to achieve conditions for sustainable development, industrial developments align with environmental development is inevitable. Among the important environmental industrial parks, providing the required water industry and entering industrial pollutants into groundwater sources. Construction of appropriate wastewater treatment systems prevent the contamination of water resources and environment and also provide a new source of water for reuse (3). Today, shortage of water for both drinking and industrial communities is a global concern. Therefore, protection of water resources is very important. there are many studies in water minimizing to solve this problem in industries with different approaches (4). Water management is a very important issue in most industrial sections, (5). Water is a very important raw material in the manufacture of tiles and its usage varies greatly between sectors and processes (6). Water consumed for the operation of various units preparation and cleaning of equipment such as slurry and glaze preparation, glazing lines, washing gases from scrubbers and etc. Major wastewater produced in these parts is only due to washing (7). A significant amount of suspended solids and turbidity in wastewater industries could be removed just by a simple sedimentation. As a result, effluent from it can only be returned to the ball mill. But have not recycled water quality necessary for use in another part especially of the preparation glazes. As a result, a significant amount of groundwater is used as the fresh water source in production line for production glaze and other coatings. However, groundwater supplies is limited. Tile industry should be find solution to decrease its groundwater consumption (5). Water recycling and reuse in the consumption cycle not only reduce consumption and has economic efficiency, but not exit wastewater pollutants to surrounding environment as a principle in order to prevent contamination of the environment should take priority. The composition of these tile industry wastewaters is include clays, frits and insoluble silicates, electrolytes, anions such as sulfate( mg/l), chloride ( mg/L), suspended and dissolved heavy metals such as lead and zinc, COD ( mg/l) and BOD ( mg/l) (6, 8). Organic materials that mainly come from the additives used in decorate the tiles (5). Contrast municipal wastewater biological treatment methods, mainly to respond. Therefore, different methods based on physico-chemical process are needed. Physical-chemicals treatment methods can be used for wastewater tile. Physical-chemical wastewater treatment including homogenization, aeration, Sedimentation, filtration, activated carbon adsorption, coagulation and flocculation, ion exchange and reverse osmosis (9).Now, coagulants compound of aluminum is very common in water and wastewater treatment and the use of these 23

3 Tile Wastewater Treatment with Different Coagulants materials increased. In addition, these are materials very cheap and easily accessible. The selection the type of coagulation is one the most important decision for the wastewater treatment and will be based on the nature of wastewater. Poly aluminum chloride (PAC) has proven to be more efficient in low dosages and in a wider ph range acts (10). Nilsalab investigated the use of the coagulation process in the ceramic industry wastewater treatment using aluminum sulfate and reported most removal efficiency of turbidity at ph 6-7 with optimal dose 200 mg/l(11). In another study fahiminia et al, the effect of different doses of coagulants including Alum, poly aluminum chloride, Polymer, Ferric chloride (Fecl 3 ) and lime on turbidity, total suspended solids and total solids, removal were investigated. The results indicated that lime in dose 25 ppm is the best coagulant for turbidity removal (99.8%) and the highest efficiency for TS removal (82.5%) is related to using Alum in dose100 ppm (12). paula et al, in 2014 studied concrete industry for wastewater treatment using a combination of aluminum sulfate and Moringa oleifera, that turbidity removal efficiency was 90 percent (13). The aim of this study was to investigate the quality of wastewater and use of coagulation-flocculation process with coagulants ferric chloride, ferric sulfate and ferrous, aluminum sulfate and poly aluminum chloride for suspended solids and turbidity reduction from wastewater in order to reuse it in the processing line. Methods: In this study sample was composed of wastewater processing line according to shift work and changes taking it. Measuring parameters ph, EC (multi-parameter model 40HQ company HACH) and temperature were determined at the spot of sampling due to changes over time. Samples were collected in 20-L plastic containers and transported to the laboratory and stored at 4 C. Experiments were carried out according to standard method for water and wastewater tests (14). Physical and chemical raw wastewater is mentioned in table 1. Table 1: Physical - chemical characteristics, raw wastewater tile industry Parameters unit Min Max Average ± SD ph ±0.6 Temperature ( C) ±1 EC (us/cm) ± Turbidity NTU ± TDS (mg/l) ±79 TSS (mg/l) ± TS (mg/l) ± COD (mg/l) ± BOD 5 (mg/l) ±

4 Zarei Mahmoud Abadi Tahereh, et al. The study was performed in laboratory scale using the jar by five coagulant ferric chloride, ferric sulfate and ferrous, aluminum sulfate as metal salts and Poly aluminum Chloride (PAC) as hydrolyzed aluminum salt. This was compounded of Merck Germany. Hydrochloric acid 1 normal and lime Ca (OH) 2 solution were used for adjusting the ph value of wastewater during the treatment processes. Details coagulants used are described in table 2. Table 2: Characteristics of coagulants used in the study Coagulants Formula Molecular weight (g/mole) No. Artie Concentration (%) ferric chloride Fecl 3.6H 2 O ferric sulfate Fe 2 (SO 4 ) 3.H 2 O sulfate ferrous FeSO 4 7H 2 O aluminium sulfate AL 2 (SO4) Poly aluminum Chloride Al 2 (OH) n Cl 6-n 10 The coagulation-flocculation process carried out using a jar test manufactured by HACH (model ). The samples were after out of the refrigerator for 2 hours at room temperature, until temperature reaches to 22 C. The sample was given 100 minutes sedimentation time. In order to determine the optimum ph coagulant materials, evaluated the different ph (7, 9, 11) in the fixed amount of coagulants (iron-based compounds 0.25 g/l and aluminum-based compounds 0.2 g/l). By measuring parameters turbidity, EC, TSS, TS, COD for each ph, a sample with the highest removal efficiency for the desired parameters, ph of the sample as optimum ph was considered. Then wastewater ph regulation at the optimum value and Followed by various amounts of coagulants materials (0.15, 0.2, 0.25, 0.3, 0.35 g/l) simultaneously added to the wastewater to the volume of one liter and it was determined the optimal amount. Wastewater and coagulants were stirred at room temperature first with rapid mixing for 1 min at 100 rpm and slowly mixing for 10 minutes at 20 rpm. At the end of slow mixing, was considered 30 minutes sedimentation for sample. After the sedimentation period, the supernatant wastewater into the beakers extracted using a plastic syringe and Measured parameters turbidity (turbidity meter TB100 model manufactured by Eutech), EC, TSS, TS, COD. Finally, optimal dose each coagulant was determined. To draw the relevant diagrams software Excel 2010 was used. In this research, in order to increase the accuracy of experiments, all experiments were repeated twice and the mean values were reported as the final result. Results: Figure 1 shows the efficiency of turbidity removal during the sedimentation, before coagulation process. According to this figure, sedimentation different times were tested on the tile raw wastewater before adding coagulants. The sedimentation time of 100 minutes, the turbidity of wastewater from to 6310 NTU decreased (39.9% of turbidity removal efficiency). Turbidity 25

5 Tile Wastewater Treatment with Different Coagulants removal efficiency almost unchanged after 100 minutes. Figures 2 to 6 show the results optimum ph about coagulants used. Ferric chloride has been effective in alkaline ph, by doing a jar test for each sample three ph, the optimum ph of 11 was obtained. The results showed that the optimum ph of ferric sulfate and ferrous the most appropriate ph obtained, is equal to 11. The results of the experiments of coagulant aluminum sulfate and poly aluminum chloride showed the optimum ph for these two coagulants is 7. For the investigation the effect of different dosages of coagulants to remove contaminants by ferric chloride, ferric sulfate and ferrous, aluminum sulfate and poly aluminum chloride at ph fixed at doses (0.15, 0.2, 0.25, 0.3, 0.35 g/l), Jar tests were performed. Figures 7 to 10 shows the effect of different doses of coagulant to remove contaminants. The results of the experiment ferric chloride coagulant showed that in dosage 0.3 g/l works well in the removal of the evaluated parameters and rate removal of turbidity, EC, TSS, TS respectively 99.84, 20.46, 99.83, Percentage and 50% removal of COD. In the case of ferric sulfate results the effect of different doses indicate that the rate removal the studied parameters at doses consumption greater than 0.3 g/l trends has been fixed and rate removal of turbidity, EC, TSS, TS respectively 99.69, 22.45, 99.71, Percentage and 72.5% removal of COD. The results of experiment ferrous sulfate coagulant showed in dosage 0.3 g/l have worked well in removing contaminants and rate removal of turbidity, EC, TSS, TS in order 99.9, 26.47, 99.9, 90.9 Percentage and 60% removal of COD. The results the effect of different doses aluminum sulfate and Poly aluminumm chloride indicate that removed studied parameters the dosage 0.25 g/l then for both coagulation trend has been fixed. The result dose 0.25 g/l was selected as the optimal dose for the two coagulants. The removal of turbidity, EC, TSS, TS and COD for aluminum sulfate, respectively 99.88, 24.95, 99.86, and 60 Percentage. For poly aluminum chloride respectively 99.92, 17.74, 99.93, and 75 percentage. Figure 1: Effect of sedimentation, before coagulation process for the removal of turbidity 26

6 Tahereh Zarei Mahmoud Abadi, et al. Figure 2: Effect of coagulants on turbidity removal efficiency at different ph Figure 3: Effect of coagulants on electrical conductivity removal efficiency at different ph Figure 4: Effect of coagulants on total suspended solids removal efficiency at different ph 27

7 Tile Wastewater Treatment with Different Coagulants Figure 5: Effect of coagulants on total solids removal efficiency at different ph Figure 6: Effect of coagulants on COD removal efficiency at different ph 100 Turbidity Removal (%) Coagulant dosage(g/l) ferric chloride ferric sulfate ferrous sulfate aluminium sulfate PAC Figure 7: The effect of coagulant dosage on turbidity removal efficiency 28

8 Tahereh Zarei Mahmoud Abadi, et al. Figure 8: The effect of coagulant dosage on total suspended solids removal efficiency 35 EC Removal(%) ferric chloride ferric sulfate ferrous sulfate aluminium sulfate PAC Coagulant dosage(g/l) Figure 9: The effect of coagulant dosage on electrical conductivity removal efficiency 92 TS Removal(%) Coagulante dosage(g/l) ferric chloride ferric sulfate ferrous sulfate aluminium sulfate PAC Figure 10: The effect of coagulant dosage on total solids removal efficiency 29

9 Tile Wastewater Treatment with Different Coagulants COD Removal (%) ferric chloride ferric sulfate ferrous sulfate aluminium sulfate PAC Coagulant dosage(g/l) Figure 11: The effect of coagulant dosage on COD removal efficiency Discussion: According to figure 1, sedimentation time of 100 minutes was selected as the best time remained before the coagulation process. The results research showed that aluminum sulfate and PAC better performance at ph 7. The important reason for such behavior is: 1- at low ph, Presence monomers particles, aluminum causing neutralization of anionic particles contaminants and sedimentation of doing better. 2- at low ph, concentration of dissolved aluminum decreased with decreasing the - Al (OH) 4 and reduce this ratio lead to the sedimentation process improvement and this anionic aluminum hydroxide reducing the effects of coagulation (10). But at alkaline ph due to the formation of fine flocs, less sedimentation and also decrease efficiency. Coagulants aluminum sulfate and PAC compared with other coagulants in the lower dose showed most of the removal efficiency of turbidity, TSS, COD. The ph and optimal dose of aluminum sulfate were consistent with studies Nilsalab (11). However, in study Mr. Fahiminia (12) with much less turbidity ferric chloride in dosage 0.5 g/l turbidity removal 99.4 percentage while in this study despite the turbidity 16 times more ferric chloride at dose 0.3 g/l Shown more efficiency for turbidity (99.84%). In the study Paula (13) despite the combination of aluminum sulfate with other coagulants removal efficiency had 90% while this study only aluminum sulfate, have been able to remove 99.88% for turbidity. COD removal rate increased with increasing coagulants.these findings show that for remove significant COD, required high doses of coagulants. This could be due to the presence of large amounts of organic matter in effluent and their reaction is with coagulants that causes the suspended matter in effluent oxidized, signed and eliminate this process can reduce wastewater COD (15). The results showed the electrical conductivity increases by increasing coagulants. Comparison of the effects these coagulants to remove contaminants showed poly aluminum chloride has a better performance compared to other coagulants. Poly aluminum chloride compared with other coagulants such as aluminum sulfate, ferric chloride, etc. in medium 30

10 Tahereh Zarei Mahmoud Abadi, et al. and high turbidity of better performance. For example, requires a lot less due to ionic load charge more, coarse clots, reduces settling time flukes, less sludge production, without the need to regulate the ph, its better performance at lower temperatures. In recent years, poly aluminum chloride is used widely as an alternative to the traditional aluminum sulfate and ferric chloride coagulant. In practical applications showed that PAC coagulant effect produced 2-3 times better than are conventional aluminum salts (16). According to consumption less in the same terms such the initial turbidity and suspended solids and etc, using a PAC the ultimate cost is more economical. Conclusion: -Coagulation and flocculation is a suitable method for remove turbidity and COD wastewater. - Due to the high turbidity wastewater tiles, this method has a high potential for practical application in wastewater with high COD and turbidity. -Having regard to the high efficiency of this method and inexpensive and does not require advanced technology as a solution for wastewater treatment producing line factories tile is recommended. Acknowledgments: The support President of the School of Public Health and laboratory experts which provide laboratory the possibility to carry out the research to be provided and their valuable guidance in this study helped us to appreciate. References: 1. Ferreira JMF, Torres PMC, Silva MS, Labrincha JA. Recycling of granite sludges in brick-type and floor tile-type ceramic formulations. J Euroceram News. 2002; 14: Nabi Bidhendi GHR, Mehrdadi N, Mohammadnejad S. Water and wastewater minimization in Tehran oil refinery using water pinch analysis. Int J Environ Res. 2010; 4(4): Aghakhani A, Sadani M, Faraji M, Boniadi NGR. Compression of methods to estimate the industrial water demand based on the number of industrial units, number of employees, Total area and the area infrastructure. J Res Health System. 2010; 6(2): Khezri SM, Lotfi F, Tabibian S, Erfani Z. Application of water pinch technology for water and wastewater minimization in aluminum anodizing industries. Int J Environ Sci Tech. 2010; 7(2): Deratani A, Palmeri J, Moliner-Salvador S, Sánchez E. Use of nanofiltration membrane technology for ceramic industry wastewater treatment.j Bolet de la Socie Españ de Cerámica y Vidrio. 2012; 51(103): Ibáñez-Forés V, Bovea M, Azapagic A. Assessing the sustainability of Best Available Techniques (BAT): methodology and application in the ceramic tiles industry. J Clean Prod. 2013; 51: Huang YI, Luo J, Xia B. Application of cleaner production as an important sustainable strategy in the ceramic tile plant a case study in Guangzhou, China. J Clean Prod. 2013; 43: Enrique JE, Monfort E, Busani G, Mallol G. Water-saving techniques in the Spanish tile industry. Tile & brick international. J Bol Soc Esp Cerám Vidrio. 2000; 39(1):

11 Tile Wastewater Treatment with Different Coagulants 9. Elsheikh MA, Al-Hemaidi WK. Approach in Choosing Suitable Technology for Industrial Wastewater Treatment. J Civil Environ Eng. 2012; 2(5): Sahu OP, Chaudhari PK, Review on chemical treatment of industrial waste water. J Appl Sci Environ Manage. 2013; 17(2): Nilsalab P, Gheewala SH. Improving the Efficiency of the Water System in Ceramic Tile Manufacturing. 2009; Fahiminia M, Ardani R, Hashemi S, Alizadeh M. Wastewater Treatment of Stone Cutting Industries by Coagulation Process. J Arch Hyg Sci. 2011; 2(1): de Paula HM, de Oliveira Ilha MS, Andrade LS. Concrete plant wastewater treatment process by coagulation combining aluminum sulfate and Moringa oleifera powder. J Clean Prod. 2014; 76: APHA, AWWA, WEF, Rice EW, Barid RB, Eaton AD. Association, Standard methods for the examination of water and wastewater. 22 nd ed. American Public Health Association, Washington, DC JouanMa X, Hui LX, Treatment of water-based printing ink wastewater by Fenton process combined with coagulation. J hazard mater, 2008; 162(1): Mirzaei A, Takdastan A, Alavi Bakhtiarvand N. Survey of PAC Performance for Removal of Turbidity, COD, Coliform Bacteria, Heterotrophic Bacteria from Water of Karoon River. Iran J Health Environ. 2011; 4(3):