EXHAUST GAS TREATMENT METHOD

摘要

PROBLEM TO BE SOLVED: To provide a method for biologically treating nitrogen compound-containing exhaust gas, preventing the clogging of a packed bed and capable of feeding a proper amount of organocarbon subsidiarily added for denitrification. SOLUTION: In the exhaust gas treatment method for passing nitrogen compound- containing exhaust gas through a microorganism carrier packed bed while sprinkling circulating water over the packed bed to treat the same and drawing out the circulating water to subject the same to denitrification treatment, the microorganism carrier packed bed is separated into a front stage 3 and a rear stage 6 and the circulating water 4 of the front stage is set to a weak alkaline pH region of 8-9 while the circulating water of the rear stage is adjusted to a weak acidic-neutral pH region of 5.0-7.2 to perform water sprinkling treatment and both of the drawn-out circulating waters are mixed to be adjusted to a neutral pH region of 6.0-8.0 to be subjected to denitrification treatment. The mixing of the drawn-out circulating waters can be performed by mixing separated sludge 11 formed by sedimentation treatment 16 and the circulating water 5 drawn out of the front stage and denitrification treatment is performed by measuring the pH value of the treated liquid to acidify this liquid and supplying an organocarbon source 10 to make the treated liquid neutral or alkaline to stop the supply of the organocarbon source.