• Membrane Journal
• /
• v.7 no.4
• /
• pp.175-182
• /
• 1997

Membrane-bioreactor process which combines anaerobic-aerobic bioreactor and membrane process, was used to remove refractory organic susbstances and dye molecule in textile wastewater effectively. Direct feeding of raw feed water to membrane process caused serious fouling on membrane. On the other hand, pretreated feed by bioreactor before the membrane process remarkably reduced the fouling and prolonged the membrane life. Removal efficiency and fouling were more dependent on the material property of the membrane rather than the membrane pore size and structure. Operation mode of hollow fiber membrane module and linear velocity in the hollow fiber influenced the ramoval efficiency and the water flux of the membrane. The combined membrane- bioreactor process was more effective in treating the textile wastewater than each single process.

• Korean Journal of Microbiology
• /
• v.54 no.1
• /
• pp.79-80
• /
• 2018

Citrobacter freundii is a facultative anaerobic and a Gram-negative bacterium of Enterobacteriaceae family, and is an opportunistic pathogen. Bacteriophages infecting C. freundii can be an effective treatment for C. freundii infections. Here, the complete genomic sequence is announced for a lytic bacteriophage CF1 infecting C. freundii isolates.

• Journal of Korean Society on Water Environment
• /
• v.38 no.4
• /
• pp.171-176
• /
• 2022

Recently, an autotrophic single-stage nitrogen removal (ASSNR) process based on the anaerobic ammonium oxidation (ANAMMOX) reaction has been proven as an economical ammonia treatment. It is highly evident that double-layered gel beads are a promising alternative to the natural biofilm for ASSNR because of the high mechanical strength of poly(vinyl alcohol) (PVA)/alginate structure and efficient protection of ANAMMOX bacteria from dissolved oxygen (DO) due to the thick outer layer. However, the thick outer layer results in severe mass transport limitation and consequent lowered bacterial activity. Therefore, the effects of the thickness of the outer layer on the overall reaction rate were tested in the biofilm model using AQUASIM for ammonia-oxidizing bacteria (AOB), nitrite-oxidizing bacteria (NOB) and ANAMMOX bacteria. A thickness of 0.5~1.0 mm is preferred for the maximum total nitrogen (TN) removal. In addition, a DO of 0.5 mg/L resulted in the best total nitrogen removal. A higher DO induces NOB activity and consequent lower TN removal efficiency. The optimal density of AO B and NO B density was 1~10% for a 10% ANAMMOX bacterial in the double-layered PVA/alginate gel beads. The real effects of operating parameters of the thickness of the outer layer, DO and concentrations of biomass balance should be intensively investigated in the controlled experiments in batch and continuous modes.

• Journal of Soil and Groundwater Environment
• /
• v.27 no.6
• /
• pp.37-46
• /
• 2022

As the amount of livestock wastewater increases, ammonia contamination in surface water and groundwater is also increasing, and its treatment is urgently needed. In this study, indigenous soil bacteria was utilized for ammonia removal in artificial wastewater and associated removal mechanisms and efficiencies were evaluated. Two batch reactors were configurated to contain natural soil and artificial wastewater at 1:10 mass ratio, and incubated for 84 and 168 hours, respectively. The results showed that ammonia was completely removed within 48 and 72 hours in the first and second reactors, respectively. There were no significant changes in ammonia concentrations in the control groups without soil. Nitrate was formed in the reactors, indicating that the main removal mechanism of ammonia was nitrification by nitrifying bacteria. Nitrate was further converted to nitrogen gas by denitrification in the anaerobic environment, which was caused by consumption of oxygen during the nitrification process.

• Resources Recycling
• /
• v.18 no.2
• /
• pp.16-29
• /
• 2009

This paper describes characteristics of pollutants in wastewater from the pulp and paper industry and biological technologies for the wastewater treatment. The wastewater from the pulp and paper industry contains high concentrations of biochemical oxygen demand (BOD) and chemical oxygen demand (COD) and shows high toxicity and strong black-brown color. In particular, organic chlorinated compounds such as dioxins and furans may be formed by the chlorination of lignin in wood chips. Thus the pulp and paper industry is recently trending toward total chlorine-free (TCF) bleaching processes. All biological technologies for pulp and paper wastewater treatment are based on the contact between wastewater and bacteria, which feed on organic materials in the wastewater, thus they reduce BOD concentration in it. Both aerobic and anaerobic treatments were found to be effective for the wastewater treatment. Furthermore, advanced technologies such as fungal application and combined biological-filtration process have been also introduced to the wastewater treatment field. These technologies would be useful for water recycling to reduce water consumption throughout pulp and paper making process.

• Journal of Korean Society of Environmental Engineers
• /
• v.35 no.7
• /
• pp.479-484
• /
• 2013

This study was performed to examine the effect of copper on the biodegradability, nitrification, denitrification and oxygen uptake rate (OUR) using batch reactor and continuous flow stirred tank reactor (CSTR) of anaerobic/anoxic/oxic ($A_2/O$). The results of this study can be summarized as follows. In the case of the effect of copper on organic treatment, the bad effect initiated when it was above 4.5 mg/L copper with batch reactor and above 2.0 mg/L copper with CSTR. Concerning the case on nitrification and removal of nitrogen, it showed bad effect when copper was above 4.5 mg/L with batch reactor for nitrification and 1.0 mg/L with CSTR for the removal of nitrogen. The bad effect on the removal of phosphorus began when it was 4.5 mg/L copper with batch reactor and 2 mg/L copper with CSTR. In the case of OUR, it decreased as microbial activity was affected when copper concentration was above 1.5 mg/L in both case of batch reactor and CSTR.

• Journal of Periodontal and Implant Science
• /
• v.29 no.1
• /
• pp.81-93
• /
• 1999

Non-surgical therapy is still an important technique in periodontal treatment. In this study, scaling and root planing(SRP) with or without concomitant subgingival curettage were compared clinically and microbiologically. 14 moderate adult periodontitis patients were included in this study. After 2 weeks from screening visit, with split mouth design, one quadrant was treated by SRP, and the opposite side was treated by SRP with subgingival curettage. Clinical measurement and microbiological analysis was taken at baseline, 1 month, 3 month post-treatment. Clinical parameters used in this study was probing depth, gingival recession, gingival index, bleeding on probing, plaque index, tooth mobility(Periotest Value). Microbiological analysis consisted of determination of the percentages of 4 bacterial groups according to morphologic type with phase-contrast microscope and measuring Black-pigmented Bacteroides after anaerobic culture. 1. There were significant changes in probing depth and gingival recession at 1 month(P<0.05), and these changes remained through 3 month. However, no significant differences were observed between two groups(P<0.05). 2. There were also significant reductions in gingival index and bleeding on probing at 1 month(P<0.05),and these reduced levels were maintained through 3 month with no significant differences between two groups(P<0.05). 3. In both groups, motile bacteria decreased significantly at 1 months(P<0.05), but increased nearly to baseline level at 3 month. 4. The percentages of Black-pigmented Bacteroides, in both groups, decreased significantly at 1 month(P<0.05), and in the subgingival curettage group, significant more reductions were observed than in the root planing group(P<0.05). At 3 month, significant reduction was found in subgingival curettage group only(P<0.05). According to these results, we surmised that concomitant subgingival curettage and root planing give some advantageous effect on bacterial recolonization.

• Journal of Microbiology and Biotechnology
• /
• v.14 no.6
• /
• pp.1120-1128
• /
• 2004

The SCBFC was composed of bilayered cathode, the outside of which was modified with $Fe^{3+}$ (graphite-Fe(III) cathode) and the inside of which was porcelain membrane, and of an anode which was modified with $Mn^{4+}$ (graphite­Mn(lV) anode). The graphite-Fe(III), graphite-Mn(IV), and porcelain membrane were designed to have micropores. The outside of the cathode was exposed to the atmosphere and the inside was contacted with porcelain membrane. In all SCBFCS the graphite-Fe(III) was used as a cathode, and graphite-Mn(IV) and normal graphite were used as anodes, for comparison of the function between normal graphite and graphite-Mn(IV) anode. The potential difference between graphite-Mn(IV) anode and graphite-Fe(III) cathode was about 0.3 volt, which is the source for the electron driving force from anode to cathode. In chemical fuel cells composed of the graphite-Mn(IV) anode and graphite-Fe(III) cathode, a current of maximal 13 mA was produced coupled to oxidation of NADH to $NAD^{+}$ the current was not produced in SCBFC with normal graphite anode. When growing and resting cells of E. coli were applied to the SCBFC with graphite-Mn(IV) anode, the electricity production and substrate consumption were 6 to 7 times higher than in the SCBFC with normal graphite anode, and when we applied anaerobic sewage sludge to SCBFC with graphite-Mn(IV) anode, the electricity production and substrate consumption were 3 to 5 times higher than in the SCBFC with normal graphite anode. These results suggest that useful electric energy might possibly be produced from SCBFC without electron mediators, electrode-active bacteria, and extra energy consumption for the aeration of catholyte, but with wastewater as a fuel.

• The Journal of the Korea Contents Association
• /
• v.20 no.8
• /
• pp.674-684
• /
• 2020

To investigate the differences of bacterial- and archaeal communities depending on kind of wastewater (municipal/livestock) and on treating conditions of basins, sludges were sampled from 10 basins of 3 municipal wastewater treatment plants(WWTP) with A2O and a activated sludge sample from a livestock WWTP. The metagenomic DNAs of the sludge samples were extracted and amplified with primers, 27F/518R for bacteria and Arch519F/A958R for archaea, and pyrosequenced with Roche 454 GS-FLX Titanium. As results, the bacterial communities in basins of municipal WWTPs were quite different from those of livestock WWTP, but within the same municipal WWTP their community structures were similar to each other regardless of different environmental conditions such as O₂. And their archaeal communities resulted from anaerobic·anoxic basins were clustered only within communities originated from the same WWTP. Furthermore Seo-bu WWTP with high bacterial diversity and species richness performed better N/P-removal compared to the orther WWTPs.

• Journal of Applied Biological Chemistry
• /
• v.54 no.1
• /
• pp.51-55
• /
• 2011

To develop a health-aid preparation of Dioscorea batatas (DB), lactic acid fermentation was attempted using a mixed starter comprising of Lactobacillus acidophilus, Lactobacillus plantarum, Bifidobacterium longum. The anaerobic fermentation of a 10% DB flour suspension gave a uniform suspension of pH 3.65, containing $8{\times}10^6$ CFU/mL lactic acid bacteria. During the administration of the lactic acid fermented DB (FDB) and DB to trinitrobenzene sulfonic acid (TNBS)-induced colitis mouse model, histological lesions, morphological damage, and myeloperoxidase acitivity were significantly reduced at a dosage of 200 and 400 mg/kg/day. Dose-response (200 and 400 mg/kg/day) studies revealed that FDB pre-treatment of mice significantly ameliorated the appearance of diarrhoea and the disruption of colonic architecture. In FDB-pretreated mice, there was a significant reduction in the degree of both neutrophil infiltration (measured as decrease in myeloperoxidase activity) and weight loss rates. Theses findings suggest that FDB exerts beneficial effects in experimental colitis and may be useful in the treatment of inflammatory bowel disease.