PURPOSE AND REQUIREMENT
The main objectives of this project are to:
1. generate experimental data on biodegradation half-life in activated sludge for three groups of substances: flame retardants, polycyclic aromatic hydrocarbons, and substances with available OECD (Organization for Economic Cooperation and Development) 314B (or equivalent) activated sludge biodegradation or 301 ready biodegradability test data;
2. determine the influence of biomass concentration on biodegradation half-life.
The range of biomass concentration used shall cover the concentrations of total suspended solids (TSS) chosen to be representative of activated sludge aeration tanks at municipal wastewater treatment plants. Five biomass concentrations shall be tested, which are set tentatively at: 1 g TSS/L, 1.5 g TSS/L, 2.0 g TSS/L, 2.5 g TSS/L and 3.0 g TSS/L (TSS = total suspended solids).
The substances to be tested shall be taken from a list of candidates provided in this document. These candidates are divided into three groups: (1) flame retardants, (2) polycyclic aromatic hydrocarbons (PAHs), and (3) substances with available OECD 314B or 301 test data.
The solids-water partition coefficient of each substance shall also be measured in order to assist in the determination of the influence of biomass concentration on half-lives.
