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Settling Transition Concentration Measurement to Quantify Sludge Settling Behavior

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A new analytical technique classified as settling transition concentration (STC) was used to determine the total suspended solids (TSS) concentration at which mixed liquor settling characteristics transition from flocculent settling (Type II) to zone or hindered settling (Type III). STC involved producing a series of MLSS/secondary effluent dilutions at with different TSS concentrations in standard settling jar. The resulting settling process was viewed both with the naked eye as well as filmed using a High Definition camcorder. The recording was analyzed utilizing a MATLAB program (what does STCD stand for) (STCD) that determined the settling classification of each mixture. STCD functions by incorporating the settling jar into a red green blue (RGB) matrix, the mixture is represented by varying color pixels. STCD analyzes these pixels via colors red, green, and blue with index values that range from 0 to 255. The program plotted the RGB values against the corresponding depth of the jar, and the plot was used to highlight the interface. STC data was analyzed for a period of six months in the Blue Plains Advanced Wastewater Treatment Plant, and it showed that the STC typically occurred between 600-700mg/L but drifted above 700mg/L for a good settling sludge, and below 600mg/L for a poor settling sludge. In addition, STC was collected for mixed liquor samples before and after the addition of Sodium ions, it was observed that STC was lowered by 100mg/L. STC proved to be a useful method in characterizing sludge settling characteristics.

Document Type: Research Article


Publication date: January 1, 2012

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  • Proceedings of the Water Environment Federation is an archive of papers published in the proceedings of the annual Water Environment Federation® Technical Exhibition and Conference (WEFTEC® ) and specialty conferences held since the year 2000. These proceedings are not peer reviewed.

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