Biofiltration onto pine bark for the treatment of water contaminated with atrazine:: influence of sorbent on Pseudomonas sp strain adp

A combination of adsorption and biodegradation processes was studied as a potential for the treatment of water contaminated with atrazine. Pine bark was used as a cheap and readily available sorbent, and Pseudomonas sp. strain ADP as atrazine degrader. Pseudomonas sp. strain ADP was found to be able to grow in the aqueous bark extract and to use the soluble bark organics as carbon sources. However, a lag period of about 25 hours was observed in cultures in sterile bark extract for the growth and atrazine biodegradation as compared with the cultures grown in a mineral medium. In pine bark aqueous extract, Pseudomonas sp. strain ADP was shown to mineralize 75% of atrazine in 330 hours (initial concentration of 44.2 mu g(.)L(-1)). The presence of sterile pine bark particles ( liquid to solid ratio of 20) in mineral medium reduced the yield down to 50% due to atrazine sorption onto bark.