Modification of Rhodamine WT tracer tests procedure in activated sludge reactors

Abstract

Abstract.One of the tracers recommended for use in wastewater treatment plants and natural waters is Rhodamine WT, which is a fluorescent dye, allowing to work at low concentrations, but may be susceptible to sorption to activated sludge flocs and chemical quenching of fluorescence by dissolved water constituents. Additionally raw sewage may contain other natural materials or pollutants exhibiting limited fluorescent properties, which are responsible for background fluorescence interference. This paper presents the proposed modifications to the Rhodamine WT tracer tests procedure in activated sludge reactors, which allow to reduce problems with background fluorescence and tracer loss over time, developed on the basis of conducted laboratory and field experiments.

Hydrodynamics and parametric study of an activated sludge process using residence time distribution technique

“…The intensity of mixing leads to enhanced mass exchange in the AT, hence directly influencing the concentration of residual polluting matter in the effluent. The knowledge of actual reactor MRT can prevent incomplete biochemical reactions in ASP and help in growth of desirable microorganisms [14,23,33]. With the optimal combination of operating parameters, optimized ASP performance can be achieved that result in minimum BOD and COD of the treated effluent [34].…”

“…However, the ASP involves several combinations of complex physical, biological and chemical processes [19], conventional RTD models as tank-in-series (TIS), axial dispersion model reported in the literature fail to provide a comprehensive view of the performance of ASP [20,21]. Compartment models are a combination of discrete reactors (CSTR and PFR) connected in a different configuration to provide a global approach to view of the hydrodynamic performance of the ASP and provide critical information for optimizing the plant operation [22][23][24].…”