1
Efficacy of Abelmoschus esculentus (Okra) Seeds, Tamarindus indica (Tamarind) Seeds and Zea mays (Corn) Husk as an Alternative to Chemical-Based Coagulants and Flocculants in Treating Wastewater
Gonz Andre’ R. Tolentino
1*, Victoria Janelle V. Baugbog
1, Mark Reejay B. Lucero , Nicole Khaite A. Sanchez
1, and Marc Wendel T. Sarmiento
11 The Canossa School, Inc.
Christian R. Geronimo
1, Research Adviser
1 Research Adviser, The Canossa School, Inc.
Abstract:
The chemical coagulants used for treating wastewater are associated with non- biodegradability resulting in health implications due to inadequate water quality standards. Thus, the study was conducted to assess the efficacy of Abelmoschus esculentus (okra) seeds, Tamarindus
indica (tamarind) seeds, and Zea mays (corn) husk as an alternative biocoagulant and a bioflocculantto chemical coagulants in treating wastewater. An experimental research design was employed wherein nine experimental groups with varying dosages and mixing speeds were evaluated regarding their relationship and difference against three
Aluminum sulfate treatments. Turbidity,Total Dissolved Solids (TDS), and pH level were water quality parameters assessed in the study wherein the coagulation-flocculation process was evaluated to treat the wastewater. Results showed that 800 mg/L at 175 RPM - 200 RPM natural treatment produces the lowest mean TDS value and produces the highest pH value. Using Two-Way ANOVA, the computed F Crit-values were 3.555 for the difference and 2.928 for the interaction. The dosage observed significant differences regarding the water quality parameters, the mixing speed observed a significant difference in pH, and the interaction between dosage and mixing speed showed a significant relationship regarding TDS. Using One-Way ANOVA, the computed F Crit-values were 2.18. Significant differences were found in terms of all the observed water quality parameters. In conclusion, natural treatments are effective in treating wastewater against Aluminum sulfate. Future researchers should increase parameters for testing, such as Dissolved Oxygen and Total Solids.
Keywords: Coagulation; Flocculation; Turbidity; Total Dissolved Solids (TDS); pH level
1. INTRODUCTION
Wastewaters from chemical industries contain heavy saline and metallic ions that are exposed to, for example, lead (Pb), which can cause significant human diseases when close to exposure. Removing these chemical contaminants is important in the field of water pollution that causes this water degradation. There are many present methods for treating
wastewater without using heavy machinery and relying on environmentally hazardous chemicals. Several studies where various aspects regarding inorganic chemical coagulants such as aluminum sulfate, aluminum chloride, sodium aluminate, ferric chloride sulfate, hydrated lime, and magnesium carbonate were involved had been restricted usage for the low efficiency, associated health risks, and non-biodegradability resulting in health implications (Agunbiade, 2016).
2 Other than this, Ayangguna et al. (2016) stated that using naturally occurring flocculants and coagulants is still highly advisable for treating wastewater. Some researchers have already demonstrated the use of naturally occurring catalysts in treating wastewater, such as the natural polymeric coagulant known as chitosan to treat COD (Chemical Oxygen demand) and turbidity. Primary processing for removing undesired parts from the plant was done with manual or mechanical pulverization. According to Zaman (2018), the next step is secondary processing (extraction), which uses organic or alcohol solvent, water, or salt solution for extraction. The third process is tertiary processing (Purification) by dialysis, lyophilization, ion exchange, or precipitation.
Natural materials found as wastes, such as Abelmoschus esculents (okra) and Tamarindus Indica, contain unutilized seeds, which the general purification of biocoagulants and bioflocculants similar to chitosan can repurpose. The seeds of these natural materials can be investigated by examining relative components and properties found in other biocoagulants and bioflocculants, such as Moringa oleifera (drumstick) seeds and Jatropha curcas (purging nut) seeds.
This study focused on the procedure for determining the efficacy of Abelmoschus esculentus (okra) seeds, Tamarindus indica (tamarind) seeds, and Zea mays (corn) husk as a coagulant and flocculant for wastewater treatment.
In addition, this paper aimed to determine the significant parameters in upcycling wastewater against Aluminum sulfate (alum). The researchers wanted to investigate the optimal dosage, mixing time, and mixing speed of the biocoagulants and bioflocculants, which would affect the parameters such as Turbidity levels, Total Dissolved Solids (TDS), and pH level.
Lastly, the researchers determined the interaction and codependence of the dosage and mixing time and speed to the parameters.
2. METHODOLOGY 2.1. Theoretical Framework
Based on the study by Ahmed et al. (2010), natural coagulants and flocculants contain antimicrobial properties that could help in controlling pathogenic organisms present in wastewater that, if not treated, can cause infection and water- borne diseases in water purification.
According to Effendi (2017), Tamarindus indica (Tamarind) seeds also contain high protein acting as a natural polyelectrolyte which is needed in decluttering the colloids present in the water. This agent is very similar to those in aluminum sulfate and ferrous sulfate.
In another study by Ang (2020), Abelmoschus esculentus (Okra) is known to be grown in tropical and subtropical areas. This can be used as a biocoagulant for water treatment since the dimeric cationic protein has a molecular weight between 12-14 kDa, and isoelectric point (pl) between 10 and 11 were predominant in adsorption and charge neutralization mechanisms. Its undergoing mechanism in flocculation, for example, the lower molecular weight of natural coagulants, such as polyethyleneimine, are usually undergoing flocculation via the charge patch mechanism.
As stated by Hu et al. (2013), chitosan contains properties of a linear cationic polymer, and cellulose surpasses aluminum sulfate for measuring turbidity present in wastewaters and the amount of sludge produced, which was due to interactions on functional groups which activate sites of pollutant particles. Through bridging mechanisms, aggregates of the wastewater chains to the Chitosan coagulant.
2.2. Research Procedure
A. Collection of Wastewater and Natural Components The researchers collected the wastewater at a river extension in Cabuyao City, Laguna. Forty (40) Litres of wastewater were collected and used for the study. The Tamarind and Okra seeds were bought at a local supermarket near Santa Rosa City, Laguna, and extracted. Fifty (50) grams of corn husk was collected, which was considered waste for the street vendors.
B. Sun Drying of Seeds and Husk
The researchers laid the okra seeds, tamarind seeds, and corn husk on a flat metal pan with a sheet of parchment paper. The natural components were placed in a window with ample sunlight for 48 hours.
3 C. Pulverization of Seeds and Husk
The collected corn husk was turned into powder by cutting, shredding, blending, and straining. Meanwhile, a mortar and pestle were used to pulverize the seeds into powder.
D. Preparation of Dosages
Constant ratio of 3:5:2 was used throughout the dosage in which 50% of the composition of the dosage is Tamarind Seed powder, okra seeds powder was 30% of the composition while the corn husk powder was 20%. The dosages were divided into three containers for the combination of the 400 mg/L,800 mg/L, and 2800 mg/L concentrations. For the aluminum sulphate, 120mg/L, 220mg/L, and 2650mg/L were set to be the constant. Each concentration will be multiplied by the amount of wastewater in the plastic container.
E. Temperature of Wastewater
The researchers tested the temperature of the sample wastewater collected and was subjected to a pretreatment wherein it must be equivalent to a temperature of (20-35° C) (Marrone, 2020).
F. pH of Wastewater
The researchers tested the pH level of the wastewater pre-treatment to match the optimum pH level of 7.25 for the coagulation and flocculation process. According to Saritha (2014), the pH influences the surface charge of coagulants and the suspension's stabilization. Sodium bicarbonate was used to treat conditions produced by high acidity in the body, such as heartburn. (RxList, 2017)
G. Creation of Coagulation-Flocculation Setup Figure 1
Coagulation and Flocculation Setup
Note: The researchers used the necessary equipment to build the setup;
the process of coagulation and flocculation starts with the design of 3 plastic containers that will hold the desired amount of wastewater. This also contains a bubble aerator for mixing the added coagulants and flocculants. A small pyramid cap is placed underneath the plastic container for all sediments and sludge. A PVC pipe and faucet are located at the lower side of the plastic container to undergo the next process of flocculation and coagulation with the same coagulant and flocculant. Previous processes will occur until it reaches the researchers’ desired arrangement. For the last plastic container, rocks and cheesecloth will be present for further wastewater filtration. A 350 ml container is placed underneath the previous plastic container. The results of the experimentation in the wastewater will determine its Turbidity, water clarity, pH level, and TDS levels.
H. Adding Coagulants Flocculants to the wastewater Depending on the dosage amount in each experimental and controlled group, the researchers will add the homogenous coagulant and flocculant, followed by a thorough mixing process and sedimentation for 1 hour. The coagulated and flocculated wastewater sample is put in a plastic container for filtration. The implemented mixing speed and time for this experimentation period were 140 rpm for 3 minutes and 40 rpm for 7 mins. After using the bubble aerator it will be left to settle down for 1 hr.
I. RPM Manipulation
The researchers manipulated the experimental groups mixing speed and time in which the first group for each 400 mg dosage will have a mixing speed of 140 rpm for 3 minutes and 40 rpm of slow mixing for 7 minutes. For the second group, a mixing speed of 175 rpm for 3 minutes and 40 rpm of slow mixing for 15 minutes. For the third group, a mixing speed of 200 rpm for 3 minutes and 40 rpm of slow mixing for 25 minutes. Lastly, for the controlled groups, 100 rpm for 4 minutes and 40 rpm of slow mixing for 25 minutes for the first group, 100 rpm for 1 minute and 40 rpm of slow mixing for 15 minutes for the second group, and 500 rpm for 1 minute and 60 rpm of slow mixing for 10 minutes for the third group.
J. Turbidity Test
A turbidity tube was improvised using a plastic cylinder, a meter stick, and a black and white disc. It was anchored on the study presented at the Water Engineering and Development Center of Loughborough University (2017). The treated wastewater was put in the plastic cylinder, and depending on the amount of volume it contains, the point where the black disc becomes less visible is the amount of NTU on the treated wastewater.
4 K. TDS and pH level Test
Total Dissolved Solids are defined as the dissolved matter through the filter with the water. The pH level test was done to determine if there was any change in pH before adding sodium bicarbonate to increase water acidity or lemon juice drop to increase alkalinity in the pre-treated wastewater. The researchers used Digital Water Quality Tester (TDS/pH/EC) to compute the amount of TDS and pH level of the water after the coagulation-flocculation process.
L. Statistical Treatment
The researchers utilized a Two-Way Analysis of Variance to determine the significant differences between the experimental groups in dosage, mixing speed, and interaction.
A One-way ANOVA test was also used to compare natural and aluminum sulfate treatments. Lastly, The Low Point Scoring System was used to determine the best coagulant-flocculant for treating wastewater.
3. RESULTS AND DISCUSSION
The researchers conducted quantitative research to determine the efficacy of okra seeds, tamarind seeds, and corn husk as an alternative to chemical-based coagulants and flocculants in treating wastewater. The data obtained were evaluated and discussed through descriptive statistics and inferential statistics.
Table 1
NTU Levels of Coagulant-Flocculant (Okra seeds, Tamarind seeds, and Corn husk)
Treatment n Min Max Mean (NTU) SD A
B C
3 3 3
24 27 30
24 30 30
24 29 30
0 1.732
1
Legend:
A - 400 mg/L of Natural Treatment B - 800 mg/L of Natural Treatment C - 2800 mg/L of Natural Treatment
Table 1 shows the different NTU (Nephelometric Turbidity Unit) levels produced by each natural coagulant- flocculant. It showed that 400 mg/L of Natural Treatment showed a mean average of 24 NTU, the lowest among the treatments. According to a study by Ayangunna & Giwa (2016), turbidity removal increases as the dosage increases;
this was evident at low dosages. However, at 400 mg/L, the turbidity decreases as it exceeds 1600 mg/L.
Table 2
TDS of Coagulant-Flocculant (Okra seeds, Tamarind seeds, and Corn husk)
Treatment n Min Max Mean (ppm) SD A
B C
3 3 3
212 203 266
226 209 278
218.33 205.00 270.00
7.0946 3.4641 6.9282
Table 2 shows the mean of Total Dissolved Solids (TDS) after applying the three (3) treatments with different dosages of the natural coagulant-flocculant. It was evident that Treatment B, the 800 mg/L natural treatment, exhibited the lowest mean with a measure of 205.00 ppm. This contradicts the study of Ali et al. (2017), where the Total Dissolved Solids may depend on different pretreatment steps used during the experimentation period, giving an increased TDS value to the wastewater sample after treatment.
Table 3
pH Level of Coagulant-Flocculant (Okra seeds, Tamarind seeds, and Corn husk)
Treatment n Min Max Mean SD
A B C
3 3 3
6.95 7.51 6.88
7.11 7.73 7.05
7.0367 7.6367 6.9933
0.0808 0.1137 0.0981
Table 3 shows the mean of the pH level produced by each treatment of the coagulant-flocculant with different dosages. It was evident that Treatment B had the highest pH value, with a pH of 7.6367. According to a study by Bote and Desta. (2021), using Moringa oleifera seed powder with the same concentrations as Tamarindus indica and Abelmoschus esculentus in the coagulation process, states that as the pH value increases, the removal efficiency increases, increasing up to 9 pH values.
5 Figure 3.1
Mean Turbidity Removal of the Wastewater in Different dosages along with Mixing speed of Treatments
Figure 3.1 shows the results of the NTU levels by dosage, along with the mixing speed. It was noted that Treatment J and K showed the least amount of NTU level at 17.0 NTU. Furthermore, it was evident that Treatment C showed the lowest NTU level at 23.0 NTU. Treatments A, B, and C obtained the three (3) lowest NTU levels for the Natural Treatments. Thus, there was no impact from the mixing speed at a dosage level of 400 mg/L. Ayangunna & Giwa (2016) stated that turbidity removal increases as the mixing speed increases. Increasing the time from fifteen (15) to 25 minutes shows an evident dip in the turbidity, which makes it rise.
Figure 2
Mean TDS of the Wastewater in Different dosages along with Mixing speed of Treatments
Figure 2 shows the Total Dissolved Solids (TDS) of each treatment in accordance with their dosage and mixing speed. It was noted that treatment E showed the lowest TDS value with a value equivalent to 190.67 ppm. Treatments D, F, and E are under the independent variable with an 800 mg/L dosage with the best resulting one at 175 RPM. Moreover, the
control group exhibited the lowest TDS value compared to the experimental groups with Treatments J, K, and L, with a mean TDS of 281.33 ppm, 298.33 ppm, and 530 ppm. The same RPM was found within Treatments J and K, in which a lower dosage exemplified a lower TDS value.
Figure 3
Mean pH of the Wastewater in Different dosages along with Mixing speed of Treatments
Figure 3 shows each treatment's mean pH level and the difference from the pre-testing pH level of 7.25. This was in accordance with the RPM and Dosage of each treatment. It was recorded that Treatment F collected the highest pH level at 7.9333. Treatments F, E, and D have a dosage equivalent to 800 mg/L. It was noted that Treatments A and G recorded a similar pH level under the mixing speed of 140 RPM. Lastly, the controlled groups recorded the lowest pH level, with Treatment L at 4.53.
The results indicate the Two-Way Analysis of Variance (ANOVA) for the Turbidity, Total Dissolved Solids (TDS), and pH level from the natural coagulant-flocculant (okra seeds, tamarind seeds, and corn husk) treatments. The computed F-critical values were 3.555 for the difference and 2928 for the interaction.
For the Turbidity, the Two-way ANOVA test for dosage concentration demonstrated that the computed F value of 51.02 indicated significant differences among the Natural treatments. Using the Tukey HSD Test on Turbidity (NTU levels), it was noted that Treatment A yields better results than treated wastewater in terms of Turbidity.
For the TDS (Total Dissolved Solids), the interaction and difference between the two (2) independent variables, dosage and mixing speed, were tested. The Two- way ANOVA test demonstrated significant differences among the dosage concentrations of the Natural treatment and the
6 relationship between dosage concentration and mixing speed variation of the Natural treatment. Using the Tukey HSD Test on TDS in terms of Dosage Concentrations in Natural Treatments, it was noted that Treatment B yields better results for treated wastewater in terms of TDS. Moreover, the Tukey HSD test was also used to compare the significant relationship between the dosage concentrations and mixing speed variations in terms of TDS between treatments. Treatment B recorded a significant difference against Treatments D, E, and F, which contained the same dosage concentrations at 800 mg/L. This shows that Treatment B yields the best results in terms of TDS.
For the pH level, the Two-way ANOVA test for dosage concentration and RPM exhibited significant differences among the dosage concentrations and RPM of the Natural treatment. Using the Tukey HSD Test on pH level in terms of dosage concentrations in natural treatments, it was noted that Treatment B (800 mg/L) yields better results for treated wastewater in terms of pH level. Furthermore, the Tukey HSD test was also used on pH levels. It shows that Treatment C (200 rpm) yields better results for treated wastewater in terms of pH level.
The results indicate the One-Way Analysis of Variance (ANOVA) for the Turbidity and Total Dissolved Solids (TDS) and pH level from the natural coagulant- flocculant (okra seeds, tamarind seeds, and corn husk) treatments and the controlled group treatments (Aluminum sulfate). The computed F-critical values were 2.18.
For the Turbidity (NTU levels), the One-Way Analysis of Variance (ANOVA) test demonstrated that the computed F value, 47.6, is greater than the obtained critical F value, which indicated significant differences between the natural treatments and aluminum sulfate treatments. Using the Tukey HSD test for the turbidity levels, results showed that Treatment I against the Treatments recorded the greatest amount of significant comparisons at 8. The control groups did not contain any significant differences among the treatments.
The controlled groups, Treatments J, K, and L recorded the most appearances of significant comparisons against the experimental groups. Only Treatment C did record a significant difference against Treatment L.
For the TDS (Total Dissolved Solids), the ANOVA test exhibited that the computed F value, 75.91, is greater than the obtained critical F value, indicating significant differences.
Using the Tukey HSD test for the TDS, it was evident that Treatment L recorded the greatest amount of significant differences, with the Treatment having a significant difference among all the other Treatments.
For the pH level, the ANOVA test exhibited that the computed F value, 74.76, is greater than the obtained critical F value, which indicated significant differences. Using the Tukey HSD test for the pH level, it was evident that Treatment F gathered the most remarkable significant differences with six (6). This was followed by Treatment E, which gathered five (5) significant differences, with only Treatment H being the differentiation from Treatment F. Treatments J, K, and L, which were the controlled groups, showed significant differences among the experimental treatments A to I. At the same time, treatment L had no evident differences.
Based on the Low Point Scoring System, the best treatment for treating wastewater in terms of turbidity, TDS, and pH level were Treatment E and Treatment F, which were under the same dosage group of 800 mg/L. This was followed by Treatments C, and D. Six experimental groups obtained a higher rating than the best-performing controlled group, which were Treatments E, F, C, D, B, and A.
4. CONCLUSIONS
Based on the results and discussion of the study, the different dosages of the natural treatments (okra seeds, tamarind seeds, and corn husk) had significant effects on the turbidity TDS, and pH of the wastewater, while the mixing speed only exhibited substantial differences in terms of pH level. Moreover, it was also analyzed that there was a significant interaction present between the mixing rate and dosage of the natural treatments in terms of the TDS of the wastewater. Significant differences were also present when the natural treatments were compared to the controlled groups (aluminum sulfate) in terms of turbidity, pH level, and TDS.
Between all the treatments of the natural coagulant-flocculant (okra seeds, tamarind seeds, and corn husk) and the controlled group treatments (aluminum sulfate), it was recorded that Treatments J and K, which were the controlled groups, exhibited the best results in terms of turbidity by obtaining the lowest turbidity after the coagulation-flocculation process.
Treatment F produced the best results in terms of TDS by recording the lowest TDS value compared to the other treatments. Treatment E had the best results in terms of pH level by recording the most alkaline or the highest pH value between the treatments. Furthermore, the experimental groups observed an increase in pH and a decrease in TDS as the dosage decreased and increased between 800 mg/L.
The study’s findings suggest the likelihood of okra seeds, tamarind seeds, and corn husk as an alternative to
7 chemical-based coagulants and flocculants in treating wastewater. Furthermore, it indicated a relationship between the flocculation process and the coagulation dosage in improving the capability of treating wastewater.
5. ACKNOWLEDGMENTS
The researchers would like to extend their utmost thankfulness to our Almighty Father for His never-ending guidance. We lift this achievement with grace and upon Him to the panelists, who gave their time and effort with their comments and suggestions to improve the study. To their grammarian, Ms. Sarah Angela B. Gacutan, who helped them with the wording and structure of their paper, constantly giving out help and comments to do their research in an understandable state. To the parents who supported the researchers, both morally and financially, helping them to conduct this research. To the Local Government of Mariquita, for allowing the researchers to collect wastewater for the experimentation. Lastly, thank the researchers’ Capstone adviser, Mr. Christian R. Geronimo, for enthusiastically contributing his knowledge.
6. REFERENCES
Agunbiade, M., Pohl, H.C., Anofi O.T. Ashafa, (2016). A review of the application of bioflocculants in wastewater treatment. Polish Journal of Environmental Studies, 25(4):1381–1389
Ahmed T., Kanwal R., Hassan H., Ayub N., Scholz M., McMinn W., (2010). Coagulation and disinfection in water treatment using Moringa, Proc. Inst. Civil.
Eng.- Water Manag., 163, 381-388
Ang T.H., Kiatkittipong, K., Kiatkittipong, W., Chua, S.C., Lim, J.W., Show, P.L., Bashir, M.J.K., Ho, Y.C., (2020). Insight on Extraction and Characterisation of Biopolymers as the Green Coagulants for Microalgae Harvesting. 12(5):1388.
https://doi.org/10.3390/w12051388
Ayangunna R., Giwa A., Giwa S., (2016) Coagulation- Flocculation Treatment of Industrial Wastewater Using Tamarind Seed Powder. International Journal of ChemTech Research, 9(5): 771-780
Desta, W. M., & Bote, M. E. (2021). Wastewater treatment using a natural coagulant (Moringa oleifera seeds):
optimization through response surface methodology. Heliyon, 7(11), e08451.
https://doi.org/10.1016/j.heliyon.2021.e08451 Effendi H. (2017). “Tamarindus indica Seed as Natural
Coagulant for Traditional Gold Mining Wastewater
Treatment.” Retrieved from:
https://www.idosi.org/wasj/wasj35(3)17/1.pdf Hu C.-Y., Lo S.-L., Chang C.-L., Chen F.-L., Wu Y.-D., Ma,
J.l., (2013). Treatment of highly turbid water using chitosan and aluminum salts, Sep. Purif. Technol., 104, 322-326.
Marrone M. (2020). Temperature Control of Wastewater during Water Treatment Process.
https://waterchillers.com/blog/post/temperature- control-of-wastewater-process
Reed, B., Smith, M., & Shaw, R. (2017). Measuring the Turbidity of Water Supplies. WEDC Publications.
Retrieved from: https :// wedc-knowledge.
lboro.ac.uk/resources/booklets/G031-Measuring- turbidity-in-water-supplies-booklet
Saritha T. (2014). Application of Sodium Bi Carbonate for the Production of Sodium Gluconate Through Fermentation Technology. International Journal of Engineering Research & Technology (IJERT), 3(11).
Shan, T. C., Matar, M. A., Makky, E. A., & Ali, E. N. (2016).
The use of Moringa oleifera seed as a natural coagulant for wastewater treatment and heavy metals removal. Applied Water Science, 7(3),1369–
1376.https://doi.org/10.1007/s13201-016-0499-8 Zaman B. (2018). Potential of Natural Flocculant in
Coagulation-Flocculation Wastewater Treatment Process. Retrieved from: https://www.e3s- conferences.org/articles/e3sconf/pdf/2018/48/e3sco nf_icenis18_05006.pdf
