Activated sludge inhibition tests for acrylic/ methacrylic acids and derivates

acrylic acid and derivates are commercially important and widely used compounds. They
have been the subject of numerous animal toxicity studies covering a variety of exposure routes, but
there is little or contradictory literature data on the activated sludge inhibition. This paper reports the
results obtained from EC50 activated sludge inhibition tests for α-, β-unsaturated acids (acrylic and
methacrylic acid) and their derivatives: amides (acrylamide, methacrylamide) and esters (methyl
acrylate, ethyl acrylate, butyl acrylate, and respectively methyl methacrylate, ethyl methacrylate and
butyl methacrylate). The tests were carried out in similar conditions according to the international
standard SR EN ISO 8192 – Water quality – Tests for inhibition of oxygen consumption by activated
sludge. The experimental results show that toxicity increases in the series of amides–acids–esters,
the acrylic compounds are more toxic than the methacrylic ones and toxicity increases in the esters
series along with an increase in the number of carbon atoms in the alkyl group.