METHOD FOR TREATING WASTEWATER WITH HIGH NO3-N CONCENTRATION USING FIXED BED BIO-FILM REACTOR

摘要

PURPOSE: Provided is a method for treating wastewater with high NO3-N concentration using fixed bed bio-film reactors that are packed with pall ring as contact media. This system is designed for use in wastewater over 200 mg-N/L, and an effective amount of carbon source is injected into bio-film reactor corresponding to NO3-N concentration. CONSTITUTION: In the method, wastewater with high NO3-N concentration flows into a pH adjust tank (1), in which a device (5) for measuring pH and consequently supplying buffer solution is installed and the pH adjust tank is controlled to pH 7.0-7.5. A device (2) for measuring NO3-N concentration and supplying carbon source (methanol used commonly) to wastewater is installed between the pH adjust tank and the bio-film reactor (11) and carbon source is preferably fed in a ratio of 2.5 to 3.0g-methanol/g-NO3-N. Then, wastewater flows into the fixed bed bio-film reactors (11,12), microorganism concentration of these reactors are maintained at 0.2-0.5 g-microorganism/pall-ring respectively. In the reactor, diffusers (7) installed to maintain proper microorganism concentration periodically emit air bubbles, thereby avoids clogging and channeling. Also, the pH adjust tank is connected to the bio-film reactor (11) through a recycling pipe (6) to cope with load variation.