Trickling Filters and RBCs · Sloughing and Solids
What Is Sloughing in a Trickling Filter?
The tests in Module 4 showed that TSS and BOD both rise when solids escape. This module explains where those solids come from and how the plant removes them. Sloughing is when biofilm breaks loose from the media. As the film grows, some of it loses its grip. Flowing water or rotation can also tear it off. Sloughing is a normal part of fixed-film treatment.
In a trickling filter, loose solids move down through the media and the underdrains. In an RBC, rotation and moving water keep the loose material in the liquid. In both processes, these solids must travel on to downstream solids removal.
Sloughing can happen slowly or in a larger burst. Changes in flow, temperature, or load can change how much comes off. So can toxic material, drying, restarting a unit, or a mechanical upset.
Do not treat every rise in suspended solids as a biological failure. Find the source. It may be sloughed growth, solids from upstream, poor downstream removal, a sampling error, or something else.
Key point: Sloughing is normal, but its amount, its timing, and how it is handled downstream decide its effect on effluent quality.
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Trickling Filters and Rotating Biological Contactors
This page comes from the course. It covers biofilm, trickling filter equipment, recirculation and loading, lab tests, sloughing, RBCs and common operating problems, one step at a time, with short knowledge checks and a certificate of completion.
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