Effect of organic toxicants on the activity of denitrifying granular sludge

Abstract

Denitrification plays a key role in the biological nitrogen removal from the wastewater using granular sludge as the integral part of a high-rate denitrification technology. It is helpful to evaluate the effect of typical organic toxicants on the activity of denitrifying granular sludge for the application of denitrification technology. In this study, four typical organic toxicants, namely, penicillin, chloramphenicol, 2,4-dinitrophenol and polymyxin B sulphate were used to assess the effect of organic toxicants on the activity of denitrifying granular sludge. The results of individual toxicity indicated that penicillin, chloramphenicol and 2,4-dinitrophenol had significant inhibition, whose half-inhibitory concentrations were 0.534, 0.162 and 0.474 g/L with respective inhibitory magnitudes of 90.79%/(g/L), 282.5%/(g/L) and 138.83%/(g/L). Polymyxin B sulphate showed no significant inhibition. The results of combined toxicity indicated that the binary mixture of penicillin and chloramphenicol had an antagonistic effect, both the binary mixture of penicillin and 2,4-dinitrophenol and the binary mixture of chloramphenicol and 2,4-dinitrophenol had additive effects. The ternary mixture of penicillin, chloramphenicol and 2,4-dinitrophenol had a partial additive effect.

Cellular electron transfer in anaerobic photo-assisted biocathode microbial electrosynthesis systems for acetate production from inorganic carbon (HCO3–)

“…An appropriate amount (0.25 mM) of DNP (98%, Tianjin Kermel Chemical Industrial Co.) was subsequently added as one-dose to the catholyte. Such concentration was nonfatal on the electroactive bacteria [14] and significantly lower than the half-inhibitory concentration of 2.58 mM to denitrifying bacteria [36]. The reactors were shaken in a table concentrator (30 rpm/min, ZHWY-304, Shanghai, China) under darkness for 12 h prior to exposure to light irradiation.…”

“…The reactors were shaken in a table concentrator (30 rpm/min, ZHWY-304, Shanghai, China) under darkness for 12 h prior to exposure to light irradiation. Through this process DNP was biologically removed from the catholyte by diffusion through the bacterial cell membrane [11,36].…”

Microbial Degradation of Pesticide Residues and an Emphasis on the Degradation of Cypermethrin and 3-phenoxy Benzoic Acid: A Review

“…Through the adapted process, the new compounds could induce microorganism to produce the corresponding enzyme system or establish a new enzyme system to degrade them. Functional characteristics and changes of degradation were the most important factors [ 83 , 84 , 85 , 86 ].…”