This research was performed to investigate the dynamics of microbial community by RBC (Rotating Biological Contactor) using Rhodococcus sp. EL-GT and activated sludge. Cell counts revealed by DAPI were compared with culturable bacterial counts from nutrient agar. Colony counts on nutrient agar gave values 20∼25% and 1∼15% of cell counts (DAPI). The cell counts for the dynamics of bacterial community were determined by combination of in situ hybridization with fluorescently-labelled oligonucleotide probes and epifluorescence microscopy. Around 90∼80% of total cells visualized by DAPI were also detected by the bacteria probe EUB 338. For both reactors proteobacteria belonging to the gamma subclass were dominant in the first stage (1 and 2 stage) and proteobacteria belonging to the gamma subclass were dominant in the last stage (3 and 4 stage).

The diagnostic software for the wastewater treatment plant using activated-sluge process is developed in order to increase the efficiency of management of the wastewater treatment plant. This software is based on the expert system and the visualized user interface including the diagnosis of quantitative and qualitative data. For the generalization of this software, the initialization of each unit process and updating the files can be possible.

Fuzzy algorithm of automatic control for dissolved oxygen(DO) concentration in the aeration tank of an activated sludge process is proposed. Among variables repirometry and air flowrate are selected as significant input factors and the relationship with DO is estimated using a multiple regression model. The DO concentration and the amount of repirometry are fuzzified and the fuzzy rule base are determined. Using the fuzzy algorithm, the change of amount of air flowrate are determined and the change of amount of DO is derived.

This study was conducted to evaluate capability of dyeing wastewater treatment for 3 type reactors. These reactors were Packed Bed Reactor(PBR), Fluidized Bed reactor(FBR) and Moving Media Complete Mixing Activated Sludge reactor(MMCMAS). Experiments of PBR and FBR were performed by various packing ratios and organic loading rates, experiments of MMCMAS were performed by various organic loading rates In order to obtain SBOD_5 removal efficiencies of more than 90%, the F/Mv ratios of PBR, FBR, MMCMAS were 0.11 ㎏BOD/㎏MLVSS·d, 0.12 ㎏BOD/㎏MLVSS·d, and 0.37 ㎏BOD/㎏MLVSS·d, respectively. So MMCMAS system which has more active microorganisms showed better capability of organic removal and also stronger dynamic and shock loadings than those of PBR and FBR. In PBR and FBR, the media packing ratio of 20% showed better performance of organic matters removal effciencies than 10% and 30%, but sludge production rate at media packing ratio of 30% was relatively lower than that of 10% and 20%. When more than 90% organic matters removal efficiency was obtained, the ratios of attached biomass to total biomass at PBR, FBR, MMCMAS were 89∼99%, 87∼98%, and 54∼80%, respectvely. The ratio of attached biomass to total biomass was low in MMCMAS. This was formation of thin biofilm due to shear force between rotating disc and water. The average sludge production rates(㎏VSS/㎏BODrem.) of PBR, FBR and MMCMAS were 0.20, 0.29 and 0.54, respectively.

Pb^2+ removal capacity and initial Pb^2+ removal rate were compared between non-biomaterials (granular activated carbon, powdered activated carbon, ion exchange resin, zeolite) and biomaterials (activated sludge, Aureobasidium pullulans, Saccharomyces cerevisiae). The Pb^2+ removal capacity of biomaterials were greater than that of non-biomaterials, generally. The Pb^2+ removal capacities of non-biomaterials and biomaterials were shown on the order of ion exchange resin > zeolite > granular activated carbon > powdered activated carbon and A. pullulans > S. cerevisiae > activated sludge, respectively. In the initial Pb^2+ removal rate, the non-biomaterials showed powdered activated carbon > granular activated carbon > zeolite > ion exchange resin and the biomaterials showed A. pullulans > activated sludge > S. cerevisiae. Comparing the Pb^2+ removal capacity and initial Pb^2+ removal rate of activated sludge with those of other non-biomaterials and biomaterials, activated sludge may have an availability on the removal of heavy metal ions by the economical and pratical aspects.

The effects of temperature, initial Pb^2+, concentration and initial sludge concentration on the initial Pb^2+ removal rate and maximal Pb^2+ removal amounts in activated sludge, respectively, were investigated. The removal of Pb^2+ in activated sludge was proved to be temperature-dependent process. The initial Pb^2+ removal rate increased from 187.5 to 261.4 ㎎ Pb^2+/g sludge dry weight·min, in response to the promoted temperature from 10℃ to 60℃, while the maximal Pb^2+ removal amount (78.5 ㎎ Pb^2+/g sludge dry weight) occurred at 30℃. As the initial Pb^2+, concentration increased from 36 to 228 ㎎ Pb^2+/L at the constant temperature of 30℃ and initial sludge concentration of 1.5 g sludge dry weight/L, the time to reach an equilibrium state was almost independent of the initial Pb^2+ concentration and the equilibrium Pb^2+ removal amount was increased from 41.9 to 73.6 ㎎ Pb^2+/g sludge dry weight. On the contrary, the equilbrium Pb^2+ removal amount was decreased from 87.7 to 65.3 ㎎ Pb^2+/g sludge dry weight as the increase of initial sludge concentration from 0.22 to 1.76 g sludge dry weight/L.

This study was conducted to investigate the treatment of wastewater from acetaldehyde manufacturing plant by activated sludge process with Micrococcus roseus AW-6, Micrococcus luteus AW-22, Microbacterium lacticum AW-38 and Microbacterium laevaniformans AW-41. The COD_Mn and BOD_5 of the wastewater were 5,260㎎/L and 6,452㎎/L, respectively. pH was 1.85. The main organic component in the wastewater was acetic acid which was contained 67,600㎎/L. Optimum dilution time for activated sludge process was shown 10 times. The specific substrate removal rate(K_e) was 1.95day^-1 and the nonbiodegradable matters(S_n) were 23.2㎎/L. Saturation constant (K_e) and maximum specific growth rate(q_max) were 1,640㎎/L and 2.33day^-1, respectively. Sludge yield coefficient(Y) and endogenous respiration coefficient(K_d) were 0.28㎎ MLVSS/㎎COD and 0.02day^-1, respectively. COD_cr removal efficiency was 91% for 1.95day of hydraulic retention time.

This study was conducted to investigate the biological treatment capability of MMCMAS(Movinig Media Complete Mixing Activated Sludge) reactor for high strength organic wastewater (Average BOD=800㎎/ℓ). And this experimental results were compared previous study for low strength organic wastewater (Average BOD=150㎎/ℓ) by the same reactor. In this study, we abtained following conclusions ; (1) The laboratory MMCMAS reactor demonstrated that SBOD removal efficiencies of more than 90% can be achieved at organic loading rates of 30.9 gBOD/㎡/d for high strength organic wastewater and 39.4 gBOD/㎡/d for low strength organic wastewater, respectively. (2) The nitrification rates of MMCMAS reactor was found same results of similiar organic loading rates. (3) The ratio of attached biomass to total biomass on the moving media varied in the range of 40 to 63% and 32 to 94% for high and low strength organic wastewater, respetively. And it was varied at the various concentration of influents for the similiar organic loading rates. The sludge production rates was found approximately 0.37 gVSS/gBODrem. in MMCMAS reactor.

The treatment performances of anaerobic-aerobic activated sludge process were investigated under various operation conditions. The treatment system proposed in this study gave a relatively stable performance against hourly change of the flow rate and showed a satisfactory removal of nitrogen and phosphorus compounds under experimental conditions. The recycle ratio of mixed liquor from aerobic to anaerobic region and peak coefficient primarily controlled the extent of nitrogen removal. The recycle ratio had the optimum values which were determined by the microbial activities of nitrification and denitrification. The behavior of the treatment unit could be simulated by using the kinetic equations and reactor models which considered the treatment units as complete mixing tanks.

This study was conducted to evaluate the effects of pressure and dissolved oxygen concentration on the activated sludge and to determine the optimum depth of deep shaft process. Some results from this study were summarized as follows. 1. It is considered that low sludge product in the activated sludge system maintaining high dissolved oxygen concentration is attributed to the increase of endogeneous respiration rate caused by the increase of aerobic zone in the sludge floc. 2. The increase of dissolved oxygen concentration does not affect to the increase of organic removal efficiency greatly and therefore the limiting factor is the substrate transfer into the inner part of floc. 3. The yield coefficient, Y is decreased in proportion to the increase of oxygen concentration. In this study, Y values arre ranged from 0.70 to 0.41 according to the variation of dissolved oxygen concentration from 18.0㎎/ℓ to 258 ㎎/ℓ. 4. The optimum depth of deep shaft process should be determined within the limits of non-toxicity to the microorganism and it is about 100m in this study.

A lot of sludges occur during an activated sludge treatment process of the washing wastewater and by-product waste in the cuttlefish processing manufacture. The sludges give also out a bad smell, and their amicable reclamation is very difficult because of the limited area of the filling-up. To reduce the heavy weight and large volume of the sludges, they was burning up. After the burning up at 350℃ for 2hrs the weight(volume) of the sludges were reduced to 5% level of the initial value. In contents of the bad heavy metals for human after the burning up, cadmium and lead metal were slightly detected, while mercury and the bad others not detected.

The primary objective of this study was to examine the toxic effects of PCP on activated sludge and to analyze its metabolic responses while treating wastewater containing pentachlorophenol (PCP) in a sequencing batch reactor (SBR) system operating under different control strategies. This study was conducted in two phases 1 and 2 (8-㏊ and 12-㏊ cycles) Each phase was operated with two control strategies I and II. Strategy I (reactor 1) involved rapid addition (5 minutes to complete) of substrate to the reactor with continuods mixing but no aeration for 2 hours. Strategy II (reactor 2) involved adding the feed continuodsly during the first 2 hours of the cycle when the system, was mixed but not aerated During both phases each reactor was operated at a sludge age of 15 days. The synthetic wastewater was used as a feed. The COD of the feed solution was about 380㎎/ℓ. After the reference response for both reactors was established, the steady state response of each system was established for PUP teed concentrations of 0.1 ㎎/ℓ, 1,0㎎/ℓ, and 5.0 ㎎/ℓin SBR systems operating on both 8-hr and 12-hr cycles. Soluble COD removal was not inhibited at any feed PCP concentrations used. At 5.0 ㎎/ℓfeed PCP concentration and in SBR systems operating on phase 2, the concentrations of MLVSS were dereased; selective pressure on the mixed biomass might be increased, narrowing the range of possible ecological responses; the settleability of activated sludge was poor; the SOURs were increased, showing that the systems were shocked. Nitrification was made to some extent at all concentrations of feed PCP in SBR systems operating on phase 2 whereas in SBR systems operating on phase I little nitrification was observed, Then, nitificaiion will be delayed as much as soluble COD removal is retarded due to PCP inbition effects. Enhanced biological phosphorus removal occurring in the sytem operating with control strategy I during phase I of this work and in the presence of low concentrations of PCP was unreliable and might cease at anytime, whereas enhanced biological phosphorus removal occurring in the system operating with either control strategy . I or II during phase 2 of this work and in the presence of feed PCP concentrations up to 1.0 ㎎/ℓ was reliable. When, however, such processes were exposed to 5.0 ㎎/ℓ PCP dose, enhanced phosphorus removal ceased and never returned.