Applicability test for combined biological-chemical treatment of wastewaters containing biorefractory compounds

A fast and easy test procedure was developed to check if a wastewater containing biorefractory substances can be efficiently treated in a combined biological-chemical process. Efficient treatment is characterized by a minimum use of expensive chemical oxidant, e.g. ozone, for a specified removal. The degree of removal of DOC and COD can be obtained characterizing the general feasibility of the combined treatment. Additionally, the approximate amount of ozone needed for a specified removal of DOC (ΔO3/ΔDOC)all is obtained allowing preliminary cost estimation. The test procedure used a barometric BOD5 method for the biological removal of biodegradable compounds and simple batch ozonation experiments to oxidize organic compounds. Wastewater with high ammonia content was initially treated in nitrifying fluidized bed bioreactor. The established procedure was successfully tested with the model substance m-chloronitrobenzene (mCNB) and applied to landfill leachate.