Thursday March 10th, 2016 (By Ye Bai)
Today we continue to finish the lab section. Students were divided into three groups: coagulation, flocculation and sedimentation group, ion exchange group and disinfection group. The coagulation, flocculation and sedimentation group did the jar test with aluminum and moringa seeds on this second day of experiments.
Totally three conditions for jar tests were conducted to observe the changes in values of pH, temperature, turbidity and ammonia concentration (mg/L). In the first jar test condition, several doses of alum were used to coagulate water collected in the field with a buffer solution. Sodium bicarbonate (NaHCO3) was used to control the values of pH of the sample water collected in the field. In the second jar test condition, several doses of alum were used without a buffer solution. In the third jar test condition, several doses of crushed moringa seeds were used to coagulate water.
For the data recorded, there are four parameters of interest: pH, temperature, turbidity and ammonia concentration. There are four groups of data collected from the lab. The first one is control tests data, which recorded the initial and final data of buffered and non-buffered solution. The second one is alum in non-buffered solution which includes four jars’ data sets. The third one is alum in buffered solution. The last one is data for moringa seeds.
The experiments consolidate the understanding of the procedure of coagulation using aluminum. Detailed discussion and analysis of the results will be included in our lab reports. The information derived from these experiments will be integrated into our final recommendations for the target locations in Rwanda.