How to Run an Experiment
Overview
This sampling method for testing raw water at the Pilot Plant has been used for several semester's research. Alum or PAC is used as a coagulant and the dose can be set using process controller. Raw water running through flocculation tank can be sampled at any desired location by placing the tube settlers there. Sampling lines run to turbidimeters from the tube settlers. The tube settlers mimic sedimentation. Additionally a sampling line runs from the raw water inlet to a turbidimeter. Turbidity data is stored in a excel spreadsheet using process controller.
Because the pilot plant takes water directly from the stream, environmental conditions change all the time and affect the incoming turbidity to the plant as well as the chemical composition of the particles causing turbidity. It is incredibly important to determine the best alum dose for each day of testing to ensure the formation of good flocs and collect appropriate data. The alum dose can also be related to the plant's PAC dosage using the relationship 1 part per million is equivalent to 0.182 mg/L.
Tube Settlers are used to mimic sedimentation before the turbidity of water in the flocculator is measured. They can be moved to different locations along the flocculator in order to examine effluent turbidity at various stages of flocculation.
Data is collected using process controller. It is stored in process controller and then analyzed.
Procedure
Make a folder in AguaClara data with the date
Example - 6.18.07. This way all information for tests run that day can be saved in a separate file, making data analysis quicker and easier.
Save datalog and statelog in correct folder
Go to the configuration tab, At the bottom under and to the left of Data directory path there is a button with the picture of a folder. Click on the button and choose the folder for the directory (this will save the statelog and the datalog to the chosen folder, if a statelog and datalog already exists for that day it will start a new one in this folder)
Save a copy of the setup
Look in the folder of the last date that data was collected. The most up to date version of the setup should be in there. In this excel sheet is where variables are listed; if you change any of them note it here. This is also where the location of the tube settlers should be moved/changed. Make sure before you change anything you save it in the correct folder and call it SetUp "date"
Save a copy of process controller method
Save in the folder with the date and call it PC setup. This will allow future users to see what the logic and variables were set to the day of the experiment. If for some reason a variable is changed and not noted this will allow the user to check to see what was used. Also, if for some reason Process Controller isn't working properly and states or set points disappear then this file can be used to re-install them and is the most up to date.