Abstract
Wastewater from dyeing-industry contains high levels of organic nitrogen deriving from urea. Thus, effective nitrogen removal process is needed to reduce effluent nitrogen concentration below effluent nitrogen standard before discharging effluent to receiving waters. We have developed the novel non-woven support-surrounded cell (SSC) process for the effective and economical nitrogen removal process and acquired a patent with this process. We set up a pilot-scale SSC reactor in the dyeing-industry and continuous nitrification / denitrification treatment experiments were conducted using wastewaters from the dyeing-industry. In case of no pre-aeration treatment before the SSC treatment process using activated sludge, nitrification did not proceed and a lot of paste materials were attached on the surface of non-woven fabrics. Therefore, pre-aeration process with HRT of 12 hours before the SSC treatment process was evaluated. Most oils were degraded from the dyeing-industry wastewaters during pre-aeration process and nitrification and denitrification reactions occurred in SSC reactors. By the combination of pre-aeration process with HRT of 12 hours and the SSC treatment process using activated sludge with HRT of 1.5 days, a total-nitrogen removal efficiency of about 38% was obtained without adding an organic carbon source.
