CE 256 Lab Report 8

Coagulation and Flocculation Lab #8 CE 256L M02 Lab Date: 11/09/22 Report Due: 11/16/22 Submitted to Dr. Yanyan Zhang. Group Members: Louis Mauriot, Cristian Sanchez, Omar Saucedo, Cristina Esquivel, Brittany Hymer, Jessica Novak, Sophia Fuente, Alyssa Newman, Gabriela Guadarrama

Table of Contents INTRODUCTION ........................................................................................................................................... 3 PROCEDURE ................................................................................................................................................. 3 RESULTS ....................................................................................................................................................... 4 DISCUSSION ................................................................................................................................................. 5 REFERENCES ................................................................................................................................................ 6 APPENDIX .................................................................................................................................................... 6 List of Tables Table 1: Results for Ferric Chloride Dose List of Figures Figure 1: Graphical Plot of Dose VS. pH Figure 2: Graphical Plot of Dose VS. Turbidity Figure 3: Excel Data Details for Graphs

Initial Turbidity (NTU): 32.1 Initial pH: 8.36 Table 1: Results for Ferric Chloride Dose Varying Ferric Chloride Dose Ferric Doses (mL) Final Turbidity (NTU) Final pH 0 31.6 8.51 10 2.72 8.07 20 1.46 7.70 30 1.01 7.44 50 0.624 7.18 100 0.435 6.66 Figure 1: Graphical Plot of Dose VS. pH 0 20 40 60 80 100 120 0 2 4 6 8 10 8.51 8.07 7.7 7.44 7.18 6.66 Dose VS. pH Ferric Doses (mL) Final pH Figure 2: Graphical Plot of Dose VS. Turbidity 0 20 40 60 80 100 120 0 5 10 15 20 25 30 35 31.6 2.72 1.46 1.01 0.62 0.44 Dose VS. Turbidity Ferric Doses (mL) Final Turbidity (NTU)

DISCUSSION According to the notes written by our lab TA Dulith Rajapakshe, both coagulation and flocculation can be defined as a water treatment method that removes turbidity from water such as silt or microorganisms. To be more specific, flocculation can be defined as a physical process. This latter consists of the formation of large aggregates also known as flocs through a gentle mixing water process. Coagulation is defined as a method to neutralize the negative charge carried by small particles. Filtration unfortunately doesn’t remove small particles which is why we turn to coagulation instead. Among the different coagulants that can be used, we have the choice between polymer, aluminum sulfate, and ferric chloride. Each coagulant has a separate color that allows us to identify them, and once the turbidity matter settles at the bottom of the jars, it becomes the color of the used coagulant. To be able to determine the most efficient chemical dosage using color and turbidity (visual elements), jar tests are the most ideal apparatus for this lab. Rapid mix as we perform in the lab for 30 seconds, serves to mix the chemicals thoroughly. This first rapid mix can be defined here as the coagulation part of the experimental procedure executed. The slow mixing for a duration of 15 minutes is purposefully done to endorse particle collision and consequently floc formation. The 15-minute settling time allows for the turbidity within the samples to gather at the bottom of the jar. Based on the numerical data results obtained for the final turbidity, we can clearly conclude that the higher dose of coagulant present in a water sample, the lower the turbidity becomes. Therefore, we can conclude that the more we add coagulant, the more the water quality will improve. Coagulation reactions can vary between turbidity levels and color. The relevance of pH in water treatment is very high as we have seen several times in previous labs. The pH level variance determines the quality of the water sample being tested. The lower the pH level is, the safer the water is to drink. This can be verified thanks to the numerical lab data results obtained. As the turbidity levels decrease, the pH decreases also. Coagulation and flocculation can be used in a laboratory setting to help ensure the quality of drinking water and whether it meets the primary or secondary drinking water standards as defined in the Safe Drinking Water Act. REFERENCES - Department of Civil Engineering. (2022, Fall). CE 256 lab manual. Las Cruces, New Mexico: New Mexico State University. Retrieved from class website: Coagulation and Flocculation.pdf: 2022 Fall - C E-256 L-M02-ENVMTL. SCIENCE LAB (instructure.com) - Department of Civil Engineering. (2022, Fall). CE 256 lab manual. Las Cruces, New Mexico: New Mexico State University. Retrieved from class website: Coagulation and Flocculation Notes: 2022 Fall - C E-256 L-M02-ENVMTL. SCIENCE LAB (instructure.com)