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The StaRS Theory team designed experiments to test the hypotheses on water flow through the filter and the resulting head loss. The team analyzed the effluent turbidity and head loss data from Spring 2014 and found that while head loss depends on coagulant dosage, the results vary greatly. The experimental apparatus was rebuilt from the details of the previous semesters. The sand from the filter was removed and sieved so that sand stratification was reduced within the filter column. With the sand outside of the filter, the team tested for head loss across the mesh of the inlet and outlet pipes for the stacked rapid sand filter. In certain experiments, head loss was significant, though the collected data was rather inconclusive. A motion towards a stacked rapid sand filter without slotted pipes, as well as an accompanying experimental model, was recommended.
Spring 2015
The StaRS Filter Theory team will design designed and built an apparatus to test the clogging across slotted pipes and evaluate their performance in stacked rapid sand filters. The team will continue to test stacked rapid sand filters with varying coagulant and collect data to create a mathematical model describing filter performance.. Experiments were run for the sole purpose of clogging the slotted pipe and characterizing the extent of clogging and what conditions caused the slots to clog. The team found that instead of head loss changing as a function of coagulant dosage only, as previously hypothesized, head loss was also affected by the amount of floc buildup on the slots. The coagulant to clay ratio thus affected the clogging rate and amount of head loss that built up over time.
Fall 2015
The StaRS Filter Theory team rebuilt an apparatus with an inlet system that used an orifice, rather than copper mesh or slotted pipes. Experiments were run to test the head loss across our system with certain coagulant dosages and determine the relationship between the coagulant doses and head loss across sand. Our ultimate goal is to build a mathematical model that can be used to access the filtration performance parameters and reflects the filter's effluent turbidity, head loss, and time until turbidity breakthrough or excessively high head loss.
Spring 2016
Filter performance can be described in a mathematical model to promote the understanding of stacked rapid sand filters. A variable that has been suspected to affect filter efficiency is coagulant dosage. The StaRS filtration experimental apparatus was adjusted by removing the flow accumulator to prevent sand from entering the inlet system and adding a flocculator to create small flocs. The collected data will be used to create a mathematical model to examine how coagulant mass affects the filter's effluent turbidity, head loss, and breakthrough time.
Fall 2016
Experiments with varied PACl dosages were ran to test the performance of the stacked rapid sand filter. Head loss and effluent turbidity were collected from the experiments with influent water at 5 NTU. The data from these experiments were used to create a mathematical model on the performance of the filter. The created model will then be used to write a research paper on a model for stacked rapid sand filters. The team hopes to publish this paper.
Spring 2017
This semester, the StaRS Filter Theory team continued to research on the development of a model and summarize the findings and complete the paper that was started last semester. Team started with validating washer model assumptions and found that the washer model does not work. The team also performed literature review and completed the paper by summarizing the new modelling approach.
Fall 2017
This semester, the StaRS Filter Theory team will continue to refine the existing understanding about how the stacked sand filter functions. Current plans include conducting experiments to confirm assumptions made in developing the visual model, translating the visual model into a mathematical model, and ultimately using the mathematical model to optimize filter performance.
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