Direct filtration using coarse media and dual media filters in series

dc.contributor.author Peterson, Merrill
dc.contributor.department Civil, Construction, and Environmental Engineering
dc.date 2018-08-15T06:47:26.000
dc.date.accessioned 2020-07-02T06:00:39Z
dc.date.available 2020-07-02T06:00:39Z
dc.date.issued 1981
dc.description.abstract <p>A filtration system consisting of coarse media filters in series with standard dual media filters was proposed and evaluated as an alternative for direct filtration of high turbidity waters. The coarse media filters utilized a 3.08 mm uniform sand with a media depth of 1.32 m;The study was divided into three phases. The first phase involved the use of jar tests to determine optimum coagulants and approximate dosages for direct filtration. The jar test results were used in the second phase of study which involved laboratory pilot filter studies. The optimum alum dosage in the pilot plant studies was less than that determined in the jar test. Successful filter runs were possible with influent solids concentrations of 100 mg/l of kaolin or less. Headloss development (3 m maximum) limited the filter run lengths at kaolin concentrations of 25 and 50 mg/l. With 100 mg/l of kaolin, filter runs were terminated due to turbidity breakthrough. The third phase of the study involved a pilot plant field investigation using Des Moines river water as the raw water source. The chemical coagulants used in the laboratory did not produce acceptable results during the field study. The difference in chemical requirements was attributed to the nature of the raw water turbidity. The turbidity in the Des Moines river water was attributed mainly to the presence of diatoms;Particle deposition in the coarse media filters was recorded photographically during the laboratory filter runs. The particles were deposited in the filters by first coating the media. Next, the particles filled the media void spaces. The filling of the void spaces resulted in the development of narrow channels through which the suspension was transferred deeper into the filter;Two mathematical models were applied to the laboratory pilot filter data. Both models agreed reasonably well with the experimental data and were subsequently used to develop design curves. Design considerations for both small and large system applications were evaluated;The results of the study indicated that coarse media filters in series with standard dual media filters can be used successfully in extending the process of direct filtration to waters of higher turbidity than presently acceptable.</p>
dc.format.mimetype application/pdf
dc.identifier archive/lib.dr.iastate.edu/rtd/7462/
dc.identifier.articleid 8461
dc.identifier.contextkey 6310215
dc.identifier.doi https://doi.org/10.31274/rtd-180813-6053
dc.identifier.s3bucket isulib-bepress-aws-west
dc.identifier.submissionpath rtd/7462
dc.identifier.uri https://dr.lib.iastate.edu/handle/20.500.12876/80342
dc.source.bitstream archive/lib.dr.iastate.edu/rtd/7462/r_8209162.pdf
dc.subject Civil engineering
dc.subject Sanitary engineering
dc.title Direct filtration using coarse media and dual media filters in series
dc.type dissertation
dspace.entity.type Publication
thesis.degree.level Doctor of Philosophy
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