Basis of RBC Design:
Unit Sizing:
Organic loading is the primary design parameter for the RBC process. This is generally expressed as the organic loading per unit of media surface area per unit of time, or in units of pounds BOD5 per thousand square feet per day.
Wastewater temperatures above 55 degrees F have minimal affect on organic removal and nitrification rates; however, below 55 degrees F, manufacturers shall be contacted by the designer to obtain the various correction factors that must be utilized to determine the needed additional media surface area.
In determining design loading rates on RBC’s, the following parameters should be utilized:
1. Design flow rates and primary wastewater constituents;
2. Total influent BOD5 concentration;
3. Soluble influent BOD5 concentration;
4. Percentage of total and soluble BOD5 to be removed;
5. Wastewater temperature;
6. Primary effluent dissolved oxygen;
7. Media arrangement, number of stages and surface area of media in each stage;
8. Rotational velocity of the media;
9. Retention time within the RBC tank(s);
10. Influent soluble BOD5 to the RBC system including SBOD from in-plant sidestreams, septage dumps, etc;
11. Influent hydrogen sulfide concentrations; and
12. Peak loading, BOD5 max/BOD5 avg.; TKN max/TKN avg.