• Journal of Korean Society on Water Environment
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• v.20 no.2
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• pp.190-195
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• 2004

A new technology for advanced wastewater treatment was developed using a modified Rotating Biological Contactor (RBC) process, named as Rotating Activated Bacillus Contactor (RABC) process that utilizes Bacillus sp., the facultatively anaerobic or activated microaerophilic bacteria on multiple-stage reticular rotating carriers, as a predominant species. The RABC process for a municipal wastewater with relatively low concentrations of organics, nitrogen, and phosphorus showed stable and high removal efficiencies, less than $BOD_5$ 10 mg/L, T-N 15 mg/L, and T-P 1.5 mg/L in final effluent. The performance load of RABC process was shown to be $1.23kg{\cdot}BOD/m^2{\cdot}day$ for the first stage (average $0.31kg{\cdot}BOD/m^2{\cdot}day$ for the total stages) based on both removed BOD and converted disc area corresponding to the reticular one. The sludge produced in the RABC process is characterized by low generation rate (about $0.18kg{\cdot}MLSS/kg{\cdot}BOD$) and excellent settleability. The number ratio of Bacillus ($2.4{\times}10^6CFU/ml$) to heterotrophic bacteria ($3.6{\times}10^7CFU/ml$) inhabiting in the biofilms of the RABC process was 6.7 %, indicating that Bacillus sp. was a predominant species in the biofilms. The RABC process with reticular rotating carriers showed its excellent performance for the advanced wastewater treatment without any offensive odor problem due to organic overloading.

• Journal of Korean Society on Water Environment
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• v.21 no.1
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• pp.73-78
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• 2005

This study was performed to examine the disinfection capability of a Rotating Activated Bacillus Contactor (RABC) system, in which the predominant species, Bacillus sp. was expected to have a removal or inactivation effect of total coliforms. In a settling test with mixtures of E. coli and Bacillus sp., a high removal of E. coli was observed at $20{\sim}40^{\circ}C$, while insignificant removal at $10^{\circ}C$. In a batch test, a 4.5% addition of Bacillus sp. to activated sludge considerably enhanced the removal effect of total coliforms, indicating Bacillus sp. played an important role in improving the settlability of the sludge and coliforms. In a pilot scale RABC system, the concentration of total colifroms reduced remarkably in the settling tank, suggesting that total coliforms in the RABC process were eliminated through coagulation and precipitation, probably due to extracellular polymeric substance (EPS) of Bacillus sp. The fraction of Bacillus sp. in the total cell count in the RABC process was in the range of 4.5%~6.3%. The majority (75%) of the Bacillus sp. in the RABC process was Bacillus subtilis which is known to enhance coagulation and precipitation by producing EPS. Hence, an adoption of a RABC process might be able to eliminate the disinfection unit process from a wastewater treatment system.

• Journal of Korean Society of Water and Wastewater
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• v.30 no.1
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• pp.99-104
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• 2016

This study was performed to develop a new process technology for advanced wastewater treatment using a modified Rotating Activated Bacillus Contactor (RABC) process that adopts anoxic-oxic suspended biomass tanks to enhance nutrients removal. A modified lab-scale RABC process was applied to examine its applicability and to obtain the design factors for the optimum operation of the system. The modified RABC process showed a little more stable and high nutrients removal efficiency than the prototype RABC process: about 70% of nitrogen and 55% of phosphorous removal when the low organic loading (influent COD 200mg/L). However, the processing efficiency of nutrients removal rates was enhanced to great extent when high organic loading: nitrogen 90% and phosphorous 85% (influent COD 500mg/L). High organic loading stimulated extremely good biomass attachment on the reticular carrier RABC stage and the excellent nutrients removal, nevertheless with almost no offensive odor.

• Journal of Korean Society on Water Environment
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• v.25 no.2
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• pp.329-334
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• 2009

Bacterial numbers, such as endospore-formers, and treatment efficiencies were investigated for Rotating Activated Bacillus Contactors (RABC) and other advanced wastewater treatment processes including anaerobic-anoxic-oxic (A2O), sequencing batch reactor (SBR) and biological aerated filter (BAF). Endospore-forming bacterial numbers in the RABC showed 129-fold higher levels than those of the existing advanced systems. RABC process demonstrated the highest bacterial numbers in its bioreactors (paired t-test, p<0.01). RBC biofilms and aeration tanks of the RABC system showed 131- and 476-fold higher than other existing advanced processes, respectively. Mean treatment efficiencies of the existing systems were 83.5% for chemical oxygen demand (COD), 59.1% for total nitrogen (TN) and 76.8% for total phosphorus (TP). However, RABC process removed 96.9% for COD, 96.9% for TN and 91.9% for TP for highly concentrated food wastewater (COD>1,500 mg/L, TN>150 mg/L, TP>50 mg/L). Treatment efficiency was significantly reduced when the numbers of Bacillus genus in the bioreactors decreased below $10^6CFU/mL$. The automated RABC (A-RABC), in which dissolved oxygen concentrations are automatically controlled, showed higher treatment efficiencies compared to the RABC process. The RABC system maintained sufficient bacterial numbers for the effective treatment of highly concentrated food wastewater. Moreover, final effluent was in agreement to water quality standards.

• Journal of Microbiology
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• v.45 no.2
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• pp.113-121
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• 2007

The bacterial diversity inherent to the biofilm community structure of a modified rotating biological contactor wastewater treatment process, referred to as the Rotating Activated Bacillus Contactor (RABC) process, was characterized in this study, via both culture-dependent and culture-independent methods. On the basis of culture-dependent methods, Bacillus sp. were found to exist in large numbers on the biofilm (6.5% of the heterotrophic bacteria) and the microbial composition of the biofilms was quite simple. Only three phyla were identified-namely, the Proteobacteria, the Actinobacteria (High G+C Gram-positive bacteria), and the Firmicutes (Low G+C Gram-positive bacteria). The culture-independent partial 16S rDNA sequence analysis revealed a considerably more diverse microbial composition within the biofilms. A total of eight phyla were recovered in this case, three of which were major groups: the Firmicutes (43.9%), the Proteobacteria (28.6%), and the Bacteroidetes (17.6%). The remaining five phyla were minor groups: the Planctomycetes (4.4%), the Chlorobi (2.2%), the Actinobacteria (1.1%), the Nitrospirae (1.1%), and the Verrucomicrobia (1.1%). The two most abundant genera detected were the endospore-forming bacteria (31.8%), Clostridium and Bacillus, both of which are members of the Firmicutes phylum. This finding indicates that these endospore-forming bacteria successfully colonized and dominated the RABC process biofilms. Many of the colonies or clones recovered from the biofilms evidenced significantly high homology in the 16S rDNA sequences of bacteria stored in databases associated with advanced wastewater treatment capabilities, including nitrification and denitrification, phosphorus accumulation, the removal of volatile odors, and the removal of chlorohydrocarbons or heavy metals. The microbial community structures observed in the biofilms were found to correlate nicely with the enhanced performance of advanced wastewater treatment protocols.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.175.1-175.1
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• 2011

A rotating activated bacillus contactor (RABC) process with a series of aerobic reactors was tested in pilot scale to treat digested liquid from an anaerobic digester treating swine wastewater and sewage sludge. The influent (digested liquid) for the RABC process showed C/N ratios less than 2 as a typical feature of effluent from anaerobic digesters. The pilot process, which consists of three 3 RABC reactors, four aerobic tanks and a sedimentation tank, was operated for 210 days with a hydraulic retention time of 20 days without pH and temperature control. Since the Bacillus-enriched aerobic reactors shows high efficiencies of nitrogen removal at low DO levels less than 1.0 mg/L, they were operated at reduced aeration intensities. With relatively low concentrations of organics in comparison with nitrogen concentrations, the RABC process tested in this study showed stable and high nitrogen and organics removal efficiencies over 80%. The nitrogen removal process tested in this study was proven to be an effective and operation-cost saving (lower aeration) method to remove nitrogen without adding external carbon sources to meet the optimum C/N ratio.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.2
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• pp.169-175
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• 2007

The Bio Best Bacillus(B3) and Rotating Activated Bacillus Contactor(RABC) processes, in which Bacillus strains are predominating, are reported to remove nitrogen and phosphorus as well as organic matter effectively. Nevertheless the nutrient removal characteristics of the Bacillus strains have not been studied in detail so far. This study investigated the organic and nutrient removal by Bacillus strains, Bacillus megaterium(KCTC 3007), Paenibacillus polymyxa(KCTC 3627), and Bacillus sp. A12, C21, F12, and L1(isolated from a B3 process), by incubating the strains in 0.2% nutrient broth at $30^{\circ}C$. Burkholderia cepacia(KCTC 2966), a common activated sludge organism, was used as a reference species for comparison. Although the degradation rate was affected by the population sire, the specific removal rates of organic matter by Bacillus strains were greater by $2\sim5$ times than that of Burkholderia. In particular, the culture bottles inoculated with the endospores of Bacillus megaterium and Bacillus sp. C21, F12, and N12 showed significantly higher degradation rate than those of vegetative cells.