• Journal of Korean Society on Water Environment
• /
• v.21 no.5
• /
• pp.477-483
• /
• 2005

Anammox (Anaerobic Ammonium Oxidation) bacteria is recently discovered microorganism which can oxidize ammonium to nitrogen gas in the presence of nitrite under anaerobic conditions. The anammox process can save an energy for nitrification and need not require a carbon source for denitrification, however, the start-up periods takes a long time more than several months due to the long doubling time (approximately 11 days). In order to find the effects of seeding microorganisms, hydrazine, and nitrite concentration on the enhancement of the anammox activity, five kinds of microorganisms were selected. Among the several kinds of seeding microorganisms, the granule from acclimated microorganisms treating high concentration of ammonia nitrogen (A-1) and sludge from piggery wastewater treatment plant (A-2) were found to have a high anammox activity. In the case of A-1, the maximum nitrogen conversion rate represented 0.4 mg N/L-hr, and the amount of nitrite utilization was high compared to those of other seeding microorganisms. The A-4 represented a higher nitrogen conversion rate to 0.7 mg N/L-hr although the ammonium concentration in the serum bottle was high as 200 mg/L. Meanwhile, the anaerobic granule from UASB reactor treating distillery wastewater showed a low anammox activity due to the denitrification by the remained carbon sources in the granule. Hydrazine, intermediate product in anammox reaction, enhanced the anammox activity by representing 1.4 times of nitrogen gas was produced in the test bottle than that of control, when 0.4 mM of $N_2H_4$ was added to serum bottle which contains 5 mM of nitrite. The high concentration of nitrite (10 mM) resulted in the decrease of the anammox activity by showing lower production of nitrogen gas compared to that of 5 mM addition of nitrite concentration. As a result of FISH (Florescence In-Situ Hybridization) experiment, the Amx820 probe showed a more than 13% of anammox bacteria in a granule (A-1).

• Economic and Environmental Geology
• /
• v.38 no.5 s.174
• /
• pp.563-570
• /
• 2005

The purposes of this study are to examine a field test on heavy metal removal efficiency for AMD(Acid Mine Drainage) using fish bone and apatite, and to compare those results of the laboratory & the field tests. The duration of the field test was about one month and flow rates of AMD varied from 2.53 l/min to 12.8 l/min. From the result of the field test, removal efficiencies of apatite and those of fish bone are high for As, Fe, and Pb while those of fish born is higher than those of apatite far Al, Cd, Cu and Zn which are similar to the result of the previous laboratory test. In particular, average arsenic removal efficiency of apatite is higher$(84\%)$ than that of fish bone$(75\%)$ like the result of the previous laboratory test. In case of precipitates of phosphate compounds which are generated from chemical reaction between apatite/fish bone and AMD, those generated from apatite/AMD reactionform powder-shape while those created from fish bone/AMD reaction seem to be sludge. Therefore, apatite will be used as a precipitant for mine drainages having wide range of pH based on previous studies while fish bone will be applied as a precipitantfor AMD having lower PH and high concentration of heavy metals.

• KSBB Journal
• /
• v.20 no.6
• /
• pp.431-437
• /
• 2005

Molecular methods were employed to investigate microorganisms in a thermophilic continuous stirred tank reactor(CSTR) used for continuous $H_2$ production. The reactor was inoculated with heat-treated anaerobic sludge and fed with a glucose-based medium. Denaturing gradient gel electrophoresis showed dynamic changes of bacterial populations in the reactor during 43 days of operation. Gas composition was constant from approximately 14 days but population shift still occurred. Populations affiliated with Fervidobactrium gondwanens and Thermoanaerobacterium thermosaccharolyticum were dominant on 21 and 41 days, respectively. Keeping pH of the medium at 5.0 could suppress methanogenic activity that was detected during initial operation period. $CH_4$ and mcrA detected in the samples obtained from the reactor or inoculum suggested the heat treatment condition employed in this study is not enough to remove methanogens in the inoculum. PCR using primer sets specific to 4 main orders of methanogens suggested that major $H_2$-consuming methanogens in the CSTR belong to the order Methanobacteriales.

• KSBB Journal
• /
• v.20 no.6
• /
• pp.425-430
• /
• 2005

Thermophilic $H_2$ was produced for 1 year using a bench-scale continuous stirred tank reactor(CSTR). The CSTR was inoculated with anaerobically digested sludge after heat treatment and fed with a glucose-based medium. The reactor showed relatively short start-up period(30 days) and high maximal $H_2$ yield(2.4 mol $H_2/mol$ glucose). Keeping pH 5.0 or less suppressed methanogenic activity. Bacteria affiliated with Thermoanaerobacterium thermosaccharolyticum kept being dominant from approximately 40 days as determined by DGGE. Environmental perturbation(pH or temperature) caused the decrease of biomass concentration in the reactor and the instability of reactor performance, $H_2$ production rate and $H_2$ yield. The unstable performance was accompanied with high concentration of lactate in the effluent. Taken together, the poor recovery of CSTR after perturbations could be partly explained by low biomass concentration and/or metabolic shift of the major population in the CSTR.

• Journal of Korean Society of Environmental Engineers
• /
• v.30 no.10
• /
• pp.992-998
• /
• 2008

Recently, a new concept for nitrogen removal that is simultaneous nitrification and denitrification(SND) has been studied for wastewater treatment process. The DMR(Daiho Microbic Revolution) process that used in this study consists of two suspended anoxic, anaerobic reactors and an aerobic biofilm reactor. The function of aerobic environment and the intensity of air flow rate(2.0, 1.0, 0.5, 0.4, 0.2 L/min) were studied in the biofilm reactor; also SND and nutrient removal efficiencies were investigated. Experimental results indicated that the change in air flow did not affect COD$_{Cr}$ removal significantly. Thus sustained at 93%. The lower the air flow rate, the higher T-N removal efficiency was attained(i.e.80% at 0.2 L/min). SND efficiency was 62, 65, 72 and 78% corresponding to each air flow rate. T-P removal was sensitive to aeration intensity and removal enhanced from 75% to 96% when the air flow rate was changed from 2.0 to 0.5 L/m; however second release occured in the clarifier at 0.2 L/min. Phosphorus content of activated sludge was 5.0%, as P releases and acetate uptake a ratio of 0.75 mg P/ mg HAc.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.4 no.2
• /
• pp.55-62
• /
• 1996

The purpose of this study is the evaluation of adsorption capacity of casts for heavy metals comparing with the activated carbon. The casts was obtained from vermicomposting of the mixed organic sludges which were generated from the treatment facilities for leather wastewater and cattle wastewater. The physico-chemical characteristics of cast was investigated. Also, the batch adsorption experiments of cast and activated carbon for heavy metals were carried out, and the results were analyzed by Freundlich isotherm. The buffering capacity to the acidic wastewater was founded in the cast, and the cation exchange capacity of cast impling adsorption capacity for soluble substances was evaluated as about 55me/100g. Those were implied that the cast have a large potential as a good adsorbent for soluble pollutants in wastewater. From the results of batch experiments, the removal efficiencies of tested various heavy metals including Pb, Cu, Cd, and Cr were very high value as 89-98% for the activated car-bon, and 80~95% for the casts except for Zn. The adsorption equilibriums for the two materials were achieved within 90 minutes. The order of preferable metals in the adsorption was found to be Pb>Cu>Cd>Cr>Zn on the cast and to be Pb>Cd>Cu>Cr>Zn on the activated carbon, respectively. From the above results, it might be con-cluded that cast is effectively available as a good adsorbent to treating the heavy metal bearing wastewater.

• Journal of Korean Society of Water and Wastewater
• /
• v.23 no.4
• /
• pp.439-446
• /
• 2009

This study was performed to evaluate SND(simultaneous nitrification and denitrification)efficiency, nitrogen removal efficiency and filtration function of non-woven fabric by using submerging MBR packed with granular sulfur covered with non-woven fabric filter. Synthetic wastewater was used as influent wastewater. Concentration of $NH_4{^+}-N$ in influent was maintained about 40 mg/L and the experiment was performed in four phases according to the flow rate. Nitrogen loading rate divided four phases ranging from $0.04 kg\;NH_4{^+}-N/m^3-day$ to $0.16 kg\;NH_4{^+}-N/m^3-day$. As a result, the maximum $NH_4{^+}-N$ removal rate was accomplished at $0.142 kg\;NH_4{^+}-N/m^3-day$ in nitrogen loading of $0.147 kg\;NH_4{^+}-N/m^3-day$. Nitrification efficiency was higher than 95% in all phases. $NO_3{^-}-N$ loading rate was adjusted ranging from $0.22 kg\;NO_3{^-}-N/m^3-day$ to $0.89 kg\;NO_3{^-}-N/m^3-day$. The maximum $NO_3{^-}-N$ removal rate was accomplished up to $0.71 kg\;NO_3{^-}-N/m^3-day$ in $NO_3{^-}-N$ loading of $0.89 kg\;NO_3{^-}-N/m^3-day$. The maximum $NO_3{^-}-N$ removal efficiency was 95% in $NO_3{^-}-N$ loading of $0.22 kg\;NO_3{^-}-N/m^3-day$. T-N removal rate was 90% and concentration of T-N in effluent was 3.7 mg/L in T-N loading rate of $0.039 kg\;NO_3{^-}-N/m^3-day$. In this study, TMP in reactor with and without non-woven fabric filter were observed to define fouling of hollow-fiber membrane module. Reaching time to standard washing pressure(22 cm Hg) of two reactors were 29 days with non-woven fabric But the reactor without non-woven fabric reached standard washing pressure only after 4 days. Accordingly, non-woven fabric was demonstrated the superiority as a filtration ability. With high nitrogen removal rate and decreasing of fouling of membrane, MBR packed with granular sulfur covered with non-woven fabric filter submerging in activated sludge aeration tank can be used as an advanced treatment process.

• Korean Journal of Ecology and Environment
• /
• v.47 no.3
• /
• pp.214-218
• /
• 2014

We introduce a technical equipment of GATe (Green (algae)-tide) water combine developed by K-water. The GATe water combine consists of five modules: main body and buoyant, transfer hopper, screen conveyer, sludge remover, and separator of algae and waste. Also a sprinkler, as the pre-treatment step if necessary, is equipped to the device to spread out environmental-friendly algaecide under the circumstance that the level of algal bloom does not reach to the scum-forming condition. The overall module system of this device is very simple. Based on the field test, the device covers surface area of ca. $500,000m^2day^{-1}$ during the period from May to July, and treats water volume as much as $500,000m^3day^{-1}$ in spite of some variation depending on the water quality condition. The removal efficiency of the device appeared to be over 90%. In addition, the operating duration of the device was able to expand to cover the period between March and November. We expect this new technology can be used to solve algal bloom problems in drinking water resource and public water area.

• Clean Technology
• /
• v.18 no.2
• /
• pp.209-215
• /
• 2012

The performance and removal efficiencies of a pilot scale biofilter were estimated by using ammonia and hydrogen sulfide as the odorous gases. Expanded polyurethane foam coated with powdered activated carbon and zeolite was used as a biofilm supporting medium in the biofilter. Odorous gases from the sludge thickener of a municipal wastewater treatment plant were treated in the biofilter for 10 months and the inlet ammonia and hydrogen sulfide concentrations were 0.1-1.5 and 2-20 ppmv, respectively. The removal efficiencies reached about 100% at the empty bed retention time (EBRT) of 3.6-5 seconds except for the adaptation periods. The pressure drop of the biofilter caused by the gas flow was also low that the maximum attained was 31 mm $H_2O$ during the operation. Its stability was confirmed in the long term due to the fact that the biofilter and the polyurethane medium had a minimum plugging and compression. The microbial community on the medium is critical for the performance of the biofilter especially the distribution of ammonia oxidizing bacteria (AOB) and sulfur oxidizing bacteria (SOB). The distribution of Nitrosomonas sp. (AOB) and Thiobacillus ferroxidans (SOB) was confirmed by FISH (fluorescence in situ hybridization) analysis. The longer the operation time, the more microbial population observed. Also, the medium close to the gas inlet had more microbial population than the medium at the gas outlet of the biofilter.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.26 no.1
• /
• pp.55-64
• /
• 2018

The purpose of this study is to provide a design and operation technical guideline for meeting the appropriate design criteria to biogas utilization treating organic wastes. In accordance with the government's mid-to long-term policies on bio-gasification and energization of organic wastes, the expansion of the waste-to-energy (WTE) facilities is being remarkably promoted. However, because of the limitation of livestock manure containing low-concentration of volatile solids, there has been increased in combined bio-gasification without installing new anaerobic digestion facilities. The characteristics and common problems of each treatment processes were investigated for on-going 11 bio-gasification facilities. The seasonal precision monitoring of chemicophysics analysis on anaerobic digestor samples was conducted to provide guidelines for design and operation according to the progress of biogas utilization. Consequently, Major problems were investigated such as large deviation of organic materials depending on seasons, proper dehumidification of biogas, pretreatment of hydrogen sulfide, operation of power generation and steam. This study was conducted to optimize biogas utilization of type of organic waste(containing sewage sludge and food waste, animal manure), research the facilities problem through field investigation.