Design of a Test Kit for Determining Polyelectrolyte Dosages Prior to Direct Filtration

摘要

The purpose of this study was to develop a test kit which could be used for on-site prediction of the polymer dosage required for direct filtrtion of water sources such as streams and rivers. Criteria established for the test kit are that it be simple, rugged, fast, repeatable, and compact. An ideal test kit would be one that could predict effluent turbidity, run length, and potential failures, besides optimum polymer dosage. The first test kits tried represented very simple and quick methods: pouring dosed influent through granular or paer media filters. Side-by-side tests using these test kits and the Army pilot multi-media filter showed that these techniques would not be suitable. A small scale multi-media test kit called an interface monitoring test kit, was successfully developed that approached the ideal test kit requirements. This test kit, which monitors effluent turbidity through coal mdeium, as well as through all the media under steady state conditions, appears to be the most promising test ket method because: It uses the identical filtration mechanisms as the full-scale filter. It sensitively and accurately predicts optimum polymer dosage and closely approximates the effluent turbidity of the full scale filter. It is a renewable test kit, i.e., backwashing allows it to be repeatedly reused requiring only small quantities of polymer for each test. It can be constructed and repaired, if necessary, from off-the-shelf components. The process design for the test kit is included in this report. It is recommended that a prototype test kit be constructed and tested on a variety of natural water courses.