Degradation of 4-Chlorophenol by a Moderately Halophilic Bacterial Consortium under Saline Conditions.

Aims: To investigate the degradation of 4-chlorophenol by a moderately halophilic bacterial consortium and to study the effect of nitrogen sources on the degradation of 4- chlorophenol. Study Design: 4-chlorophenol degradation by moderate halophiles. Place and Duration of Study: Centre for Environmental studies, Microbiology Lab, Anna University, Chennai, Tamil Nadu, between Jan 2009 and May 2009. Methodology: 4-chlorophenol was degraded with the moderately halophilic bacterial consortium in the minerals salts medium and degradation was analysed by gas chromatography. Effect of NaCl concentrations and alternate nitrogen sources on the degradation of 4-chlorophenol was determined. Results: The bacterial consortium was able to degrade 4-Chlorophenol at a range of NaCl concentrations, where the optimum degradation was obtained at 50 g/L of NaCl. Addition of alternate nitrogen sources like tryptone and urea did not enhance the degradation of 4- Chlorophenol. Conclusion: Bacterial consortium degraded 4-chlorophenol at optimum NaCl concentration of 50 g/L of NaCl. Addition of yeast extract as nitrogen source showed higher degradation than the nitrogen sources.

Removal of nutrients in denitrification system using coconut coir fibre for the biological treatment of aquaculture wastewater.

Ideal bacterial support medium for fixed film denitrification processes/bioreactors must be inexpensive, durable and possess large surface area with sufficient porosity. The present study has been focussed on removing nitrate nitrogen at two different nitrate nitrogen loading rates (60 (NLR I) and 120 (NLR II) mg l-1) from simulated aquaculture wastewater. Coconut coir fibre and a commercially available synthetic reticulated plastic media (Fujino Spirals) were used as packing medium in two independent upflow anaerobic packed bed column reactors. Removal of nitrate nitrogen was studied in correlation with other nutrients (COD, TKN, dissolved orthophosphate). Maximum removal of 97% at NLR-I and 99% at NLR – II of nitrate nitrogen was observed in with either media. Greater consistency in the case of COD removal of upto 81% was observed at NLR II where coconut coir was used as support medium compared to 72% COD removal by Fujino Spirals. The results observed indicate that the organic support medium is just as efficient in nitrate nitrogen removal as conventionally used synthetic support medium. The study is important as it specifically focuses on denitrification of aquaculture wastewater using cheaper organic support medium in anoxic bioreactors for the removal of nitrate nitrogen; which is seldom addressed as a significant problem.