Aerobic granular treatment of 2,4‐dichlorophenol

Abstract

2,4-Dichlorophenol (2,4-DCP) fed aerobic granules were cultivated in a sequencing batch reactor (SBR). Stable and compact granules were obtained in 60 days of SBR operation. Formed granules were compact and strong with closed packed channels. After granulation, effluent chemical oxygen demand and 2,4-DCP concentrations were 95 and 2.5 mg L −1 with corresponding removal efficiencies of 96% and 95% were achieved. Degradation profile shows a high initial degradation rate which decreases later. Degradation rate was found to be directly proportional to the substrate concentration. Specific degradation rate of 2,4-DCP was 6.54 mg 2,4-DCP gVSS −1 h −1 at 60 mg L −1 and specific cell growth rate was 0.042 ± 0.02 day −1 . High optical density (OD 600 ) the system shows effective retention of biomass which is the main advantage of present technique.Des granules aérobies ontété cultivés avec succès pour la dégradation du 2,4-DCP. Des granules stables et compacts ontété obtenus après 70 jours d'opérations en réacteurà séquencement et par lots. Des efficiences de demande chimique finale en oxygène et d'élimination de 2,4-DCP s'élevantà 96% et 95% ontété atteintes. Le profil de dégradation montre que le taux de dégradationétait initialementélevé mais qu'il ralentit plus tard. On a observé une bonne correspondance entre la demande chimique en oxygène et le profil d'élimination de 2,4-DCP. Le taux de dégradation est directement proportionnelà la concentration de substrat. Le taux spécifique de dégradation de 2,4-DCPétait de 6.54 mg de 2,4-DCP gVSS −1 L −1 h −1à 60 mg L −1 et le taux spécifique de croissance cellulaireétait de 0.042 ± 0.02 day −1 . Une haute densité optique du réacteurà séquencement et par lots montre une rétention de la biomasse effective, ce qui est l'avantage principal de cette technique.

Degradation pathway, toxicity and kinetics of 2,4,6-trichlorophenol with different co-substrate by aerobic granules in SBR

“…Several techniques such as physical, chemical, electrochemical and biological methods have been proposed for efficient wastewater treatment, most of them presenting some limitations such as poor capacity, generate waste products, incomplete mineralization or high operating cost (Gonzalez et al, 2010;Mondal et al, 2010). Nowadays aerobic granulation treatments are considered to be the most effective route (Khan et al, 2010;Wang et al, 2007). Aerobic granulation is a process of microbial self-immobilization, resulting into a cell-structured shape characterized by dense biomass (Khan et al, 2011).…”

Aerobic granulation for wastewater bioremediation: A review

“…These particles served as the cores of granules and stimulate the granulation. FTIR, GC/MS showed that 2-CP biodegradation occurred via chlorocatechol and modified ortho-cleavage pathway Khan et al (2011a) 2,4,6-TCP degradation by aerobic granules in presence of glucose and acetate as co-substrates. Nitrate presence was the best option for phosphorus-rich effluents (3.04 mg P mg −1 N), while nitrite was more useful with the simultaneous nitrification-denitrification and phosphorus removal of nitrogen-rich influents (1.68 mg P mg −1 N) Coma et al (2010) Bioremediation of 2-CP by aerobic granules in SBR Aerobic granules were successfully cultivated for removing 2-CP with a COD removal efficiency of 94%.…”

“…The knowledge of kinetics of aerobic biodegradation of toxic substances is a very important issue both for the prediction of their fate and the design of wastewater treatment plants (Khan et al, 2011a). The kinetic investigations were carried out to study the time required for the attainment of equilibrium during the biodegradation of toxic compounds.…”

“…The formation of aerobic granules consists of five stages: microbes' multiplication phase, floc appearance phase, floc cohesion phase, mature floc phase and aerobic granule phase (Hailei et al, 2006;Khan et al, 2011a). The granules thus formed are compact and strong with very high degradation efficiency.…”

“…SBR is run in batches with a cycle time of 4, 6 or 8 h or even longer with a 40%, 50% or 60% volumetric exchange ratio. Mostly, a 50% volumetric exchange ratio has been maintained (Khan et al, 2011a). SBR containing activated sludge is fed with an appropriate amount of substrate along with co-substrate in mineral salt medium (nutrients solution) for cultivating aerobic microbial granules (Moy et al, 2002).…”