Controlled dosing of flocculating agent for clarifying water - with rapid response to pattern of several turbidity tests

摘要

The turbidity of the treated water is measured continuously after sepn. of the coagulate, e.g. by filtration or centrifuging. Before the incoming suspension is processed, two samples are taken. The first sample is dosed with a higher percentage, x%, of coagulant than that use in the process. The second sample is dosed with a percentage of coagulant which is slightly higher or slightly lower than x%. Each sample is cleared of its coagulate and its turbidity measured. This provides three points on a curve relating turbidity with treatment dose percentage. The curve has a known minimum value for turbidity, established in advance by laboratory test. It is, therefore, clearly indicated if and how the process dose of coagulant should be adjusted to reduce turbidity and/or usage of coagulant.