Hach-Lange RTC113 ST-Module - Manual (Page 14)

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General information
2.5.4 Operating modes
The RTC113 ST-Module can be operated as a combined open-loop and closed-loop
controller. Several variants can be configured.
1. Configuration of a specified polymer rate [L/h] with a specified feed flow rate [m
3 /h].
2. Configuration of a specified specific polymer dosing rate [g polymer/kg TSS]. One of
the following settings is adjusted:
a. The polymer flow rate according to the TSS concentration and the feed flow rate
( Figure 4 ).
• Based on the actual feed flow rate [L/h] and TSS concentration [g/L] in the feed
flow, the polymer dosing rate [L/h] is calculated for the required specific dosing
rate.
Or:
b. The feed flow rate according to the specified polymer dosing rate and the
measured TSS concentration of the influent ( Figure 5 ).
• Based on the measurement value of the TSS concentration from the influent [g/L]
and the configurable specified polymer dosing rate [L/h], the feed flow rate [m 3 /h]
is calculated such that it corresponds to the pre-defined specific polymer dosing
rate [g/kg].
3. Both variants 2a and 2b can be combined with the closed-loop controller described
below:
a. Closed-loop control of the TSS concentration in the thickened sludge
•
The specific polymer dosing rate is adjusted according to the difference between
the target and actual TSS concentration in the outlet.