Abstract
Biological activated carbon (BAC) treatment of drinking water can remove trihalomethane (THM) precursors by adsorption and biodegradation, and also produce fresh THM precursors by bacterial activities. In this work, the changes in THM formation potential (THMFP) of the broth of mixed batch culture of bacteria were measured during the passage of culture time, the classification of THM precursors produced by bacterial activities was tried, and the biodegradability and adsorbability onto activated carbons of those precursors were investigated. The following was clarified.
The fresh THM precursors produced by bacterial activities in BAC involve the metabolic products released when bacteria are growing and the autolysis products released when they die. The former is easily biodegraded and is not contained in the BAC effluent. On the other hand, since the latter can be regarded to be non-biodegradable, it can flow out of BAC. Also, the latter is well adsorbed onto the activated carbon with mesopores of 1.5-10 nm in radius. The activated carbons with such pore-size distribution are considered to be effective for controlling THMFP of the BAC effluent.
