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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.
Process Controller was used as our main data collection tool. Excel was then used to analyze the data that was collected. Process Controller is a software package that is used to control the raw water pump, the alum pump and data collection. For the raw water pump Process Controller only controls the on/off status of the pump. When the flocculator is running the raw water pump is turned on and the flow rate is controlled by a valve that can only be changed in increments. The flow rate was calculated by partially draining the flocculator to below the outlet pipe height. The valve was then opened to a noted location and the time it took for the water to rise 5 cm was recorded. To calculate the flow rate increase in the volume of water in the tank was divided by the time it took for that volume to fill in the tank. The volume was calcuated by multiplying the height the water rose in the tank by the cross sectional area of the tank. When this technique was used the head loss over the flocculator was small and did not affect the measurement. If the head loss increases then a new way to measure the head loss will need to be created. The choice of location for the tube settlers was chosen originally to establish general information about how flocs were forming in each individual section of the flocculator.
The states utilized by process controller allow the flocculator to run continuously and data to be collected about how alum dose and changes in Gθ affect flocculation and settled water turbidity With the configuration of the baffles spaced evenly throughout the flocculator G remains constant through the 3 sections. However, by sampling at different locations the volume of the flocculator that the water travels through changes which changes θ and thus Gθ. The tube settlers were placed one at the end of each section. Original Tube settler set-upThis figure shows the configuration that was originally tested and used to collect data. This configuration was chosen to get a general understanding of how each section contributed to floc formation and final settled water turbidityData is collected using process controller. It is stored in process controller and then analyzed.