SHOCK AND TRANSIENT LOADING ON ANAEROBIC REACTOR COUPLED WITH ADSORBER

The resilience and operational control of a unique reactor design was studied in a series of transient experiments. The reactor design inclu ded an expanded-bed granular activated carbon (GAG) anaerobic reactor with a GAC adsorber located in the recycle line. The reactor was subje cted to variable loadings, a shutdown period, and a step decrease in t he hydraulic residence time (HRT). During the variable-loading experim ent, the influent chemical oxygen demand (COD) loading was increased f rom 24 kg COD/m(3)-d to 71 kg COD/m(3)-d, three times. After extended operation at 71 kg COD/m(3)-d, severe biological inhibition was observ ed and reactor failure was imminent. Rapid recovery was facilitated by the replacement of GAC from the GAC adsorber. Adsorbed organics provi ded substrate during a 60 h shutdown, and removal efficiencies were no t affected. A step decrease in the HRT from 1 d to 2.8 h did not affec t biological removal efficiency and washout of attached biomass was ne gligible. When subjected to severe transient operation, the performanc e of this reactor system was robust, and operational control allowed f or rapid recovery from severe inhibition.