A NEW ACTIVATED SLUDGE PROCESS CONTROL TESTUNCOVERS SECONDARY CLARIFIER INEFFICIENCIES

摘要

A program was implemented at the Littleton/Englewood Wastewater Treatment Plant to monitorthe flocculating, settling, and compacting characteristics of the TFSC sludge on a routine basis.These sludge quality characteristics were quantified in terms of the flocculated suspended solids(FSS) concentration, the 5-minute settled sludge volume, and the 30-minute settled sludgevolume, respectively, performed in a single, modified settlometer test. The paper discusses theuse of these sludge quality characteristics in making process control decisions.Comparison of the FSS and secondary effluent suspended solids (ESS) concentrationsdemonstrated why effluent quality (in this case, the ESS concentration) should not be used tomake process control decisions. Changes in SRT caused changes in the settling and compactingcharacteristics, but additional, unknown factors are at play. The settling and compactingcharacteristics of the sludge did not affect the sludge’s flocculation potential. Low airtemperatures worsened the hydraulic inefficiencies of the Littleton/Englewood secondaryclarifiers.