The suspended-solids concentration entering a treatment and resource recovery plant is 200 mg/L in the plant influent; 3,000 mg/L in the primary sludge; 12,500 mg/L in the secondary sludge; and 3,500 mg/ L exiting the aeration basin. The concentration of total dissolved solids in the plant influent is 350 mg/L, and the concentration of total dissolved solids exiting the aeration basins is 2,300 mg/L. The BOD5 is 100 mg/L measured after primary treatment and 3 mg/L exiting the plant. Total nitrogen levels in the plant are approximately 35 mg N/L. If the F/M ratio is 0.35 g BOD5/gram MLSS-day, Estimate: (a) The hydraulic retention time of the aeration basins if the daily plant flow is 15 million liters.
(b) The organic loading rate (volumetric basis) to the aeration basins.
(c) The Treatment plant BOD and SS treatment efficiencies.
(d) The biological treatment efficiency for BOD removal
(e) The primary sedimentation sludge wasting rate m3 /d (hint, do a mass balance about the primary clarifier.