This study was conducted to investigate anoxic-RBC (rotating biological contactor) and its application in advanced municipal wastewater treatment process to remove biologically organics and ammonia nitrogen. Effluent COD and nitrogen concentration increased as the increase of volumetric loading rate. But, the concentration changes of NO2--N and NO3--N were little, as compared to COD and NH4+-N.
When the volumetric loading rate increased, COD removal efficiency and nitrification appeared very high as 96.7~98.8% and 92.5~98.8%, respectively. However, denitrification rate decreased to 76.2~88.0%. These results showed that the change of volumetric loading rate affected to the denitrification rate more than COD removal efficiency or nitrification rate.
The surface loading rates applied to RBC were 0.13~6.01g COD/㎡-day and 0.312~1.677g NH4+-N/㎡-day and they were increased as the increase of volumetric loading rate. However, the nitrification rate showed higher than 90%.
The thickness of the biofilm in RBC was 0.130~0.141㎜ and the density of biofilm was 79.62~83.78㎎/㎤. They were increased as surface loading rate increased. From batch kinetic tests, the kmaxH and kmaxN were obtained as 1.586 g C/g VSS-day, and 0.276 g N/g VSS-day, respectively.
Kinetic constants of denitrifer in anoxic reactor, Y, ke, Ks, and k were 0.678 ㎎ VSS/㎎ N, 0.0032 day-1, 29.0 ㎎ N/ℓ, and 0.108 day-1, respectively. P and Ks values of nitrification and organics removal in RBC were 0.556 g N/㎡-day and 18.71 g COD/㎡-day, respectively.
One of the Musty and earthy smell compounds in raw water is generally attributed to 2-methylisoborneol (2-MIB). It is well known that activated carbon and oxidants such as O3, ClO2 are effective ways to control 2-MIB. In isotherm equilibrium experiments, 2-MIB in distilled water was much more adsorbed to the activated carbon(A/C) than raw water containing dissolved organic carbon (DOC). The Freundlich constants(k) of distilled water and raw water were 3.36 and 0.049, and 1/n values were 0.80 and 0.42, respectively.
The 2-MIB residual rate were Y = e-0.55x~ e-0.54x with Ozone(O3) dose by 5 minutes contact time at the 241 and 353 ng/L initial concentrations. The 2-MIB residual rate were Y = e-0.32x~ e-0.35x with Chlorine dioxide(ClO2) dose by 15 minutes contact time at the 89 and 249 ng/L initial concentrations.
2-MIB was decreased from 1911 ng/L to 569ng/L by post-ozonation(70%removal efficiency) and removal efficiencies of 2-MIB by the following 4 kinds Granular Activated Carbon(GAC) process such as coal base, coconut base, wood base and zeolite+carbon base were 95.8, 89.5, 88.4, and 93.7% respectively.
This research studied the characteristics and applicability of electrocoagulation using aluminium electrode for the color and COD removal in textile wastewater. Electrocoagulation reactor used two different electrode, Fe and Al, since in the general chemical wastewater treatment, aluminium and ferrous salts were used as coagulants.
Aluminium electrode showed higher removal efficiency of color and COD than ferrous electrode did. The COD and color removal efficiency improved at the 0.192A/dm2 current density.
Thus, the electrocoagulation process with bipolar aluminium electrode showed better efficiency in the decolorization and COD removal rate of textile wastewater effluent than custom coagulants did.