• KSBB Journal
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• v.26 no.3
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• pp.237-242
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• 2011

As a number of archaea are ubiquitously found in non-extreme habitats, elucidation of their functional roles becomes currently an emerging issue. However, most of them are unable to grow in pure culture and so it remains to be established. In order to find genes lacking in the genome of an ammonia-oxidizing archaeon (AOA), we here report on the comparative analyses of an AOA genome with those of experimentally or theoretically established minimal genomes for independent growth. We assessed the genes lacking in AOA using logic of clusters of orthologous groups (COG), remote homology, consensus sequence weight matrix, function-based motif or domain, and then further excluded genes encoding hypothetical orarchaea-specific proteins. The results of these combination analyses revealed 19 candidate genes lacking in the genome of an AOA. Thus, our results provide a possibility of inducing independent growth of AOA when supplemented with product (s) of the lacking gene (s), and also give a chance for finding new proteins with novel sequence or structure space even if the predicted lacking-genes will be found using another algorithms or biochemical studies.

• Environmental Engineering Research
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• v.23 no.2
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• pp.136-142
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• 2018

The river water source of Saidabad Surface Water Treatment Plant at Dhaka, Bangladesh, is deteriorated too much to be treated by conventional treatment process due to excessive ammonia pollution. In order to improve the raw water quality before it enters into the main treatment chain, a pilot study was conducted for pre-treatment of the raw water. The objective is to investigate the rate of reduction of ammonia using the Meteor pilot, a biological pretreatment system, which is a laboratory scale Moving Bed Biofilm Reactor with a nominal volume of hundred liters, filled with 50 L of Meteor 660 media. The reduction of ammonia was quite significant on average 73%, while the reduction of COD was in a range from 20 to 60%. The Meteor pilot was able to treat and nitrify the raw water and produce an effluent that respects the guarantee of ammonia < $4.0mg\;NH_3-N/L$ when the raw water ammonia concentration was < $15mg\;NH_3-N/L$. The study identified operating parameters necessary to achieve the desired goal of adequate ammonia removal. The study results would benefit a range of systems across the country by providing guidance on the design and operation of a biological pre-treatment system for ammonia removal.

• Journal of Aquaculture
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• v.6 no.4
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• pp.311-321
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• 1993

Ammonia accumulation is regarded as the limiting factor of the first priority in water qualities of aquatic culture systems. Nitrification efficiency and characteristics in seawater were evaluated using Rotating Biological Contactor (RBC) process as a part of the recycling water treatment facilities for marine fish culture system. Ammonia removal efficiency regarded 99.7 to $83.7\%$ at the ammonia surface loading rates of 48 to $393 mg/m^2$ -day. RBC process was able to withstand to the fluctuation of influent ammonia concentrations and loading and produced the stable effluent. The mathematical model on the fixed-film biological reactor developed by Kornegay seemed to be suitable to RBC process kinetic evaluation for the recycling water treatment of the marine fish culture system. Area capacity constant (P) and half-velocity constant (Ks) in the model were 0.188g/m^2$-day and 1.25mg/l, respectively.

• Journal of Korean Society on Water Environment
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• v.27 no.5
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• pp.646-653
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• 2011

The combined system of sequencing batch biofilm reactor (SBBR) and membrane SBR (MSBR) was operated with sewage to evaluate the COD utilization for biological nutrient removal (BNR). The SBBR was operated for nitrification reactor, while denitrifying PAO (dPAO) was cultivated in MSBR with anaerobic-anoxic operation. In the SBBR and MSBR system, the enhanced biological phosphorus removal (EBPR) was successfully achieved with higher N removal. The COD utilization in combined SBBR-MSBR system was significantly reduced compared to ordinary BNR (up to 3.1 g SCOD/g (N+P) and 1.6 g SCOD/g (N+P) with different C/N/P ratio). The results suggest that a dPAO process could effectively reduce carbon energy (=COD) requirement. The combination of oxic-SBBR and anaerobic-anoxic MSBR for dPAO utilization could be an attractive alternative to upgrade the process performance in weak sewage.

• Asian-Australasian Journal of Animal Sciences
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• v.12 no.4
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• pp.629-632
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• 1999

Constructed wetlands are being used for the removal of nutrients from livestock wastewater. However, natural vegetation typically used in constructed wetlands does not have marketable value. As an alternative, agronomic plants grown under flooded or saturated soil conditions that promote denitrification can be used. Studies on constructed wetlands for swine wastewater were conducted in wetland cells that contained either natural wetland plants or a combination of soybeans and rice for two years with the objective of maximum nitrogen reduction to minimize the amount of land required for terminal treatment. Three systems, of two 3.6 by 33.5 m wetland cells connected in series were used; two systems each contained a different combination of emergent wetland vegetation: rush/bulrush (system 1) and bur-reed/cattail (system 2). The third system contained soybean (Glycine max) in saturated-soil-culture (SSC) in the first cell, and flooded rice (Oryza sativa) in the second cell. Nitrogen (N) loading rates of 3 and $10kg\;ha^{-1}\;day^{-1}$ were used in the first and second years, respectively. These loading rates were obtained by mixing swine lagoon liquid with fresh water before it was applied to the wetland. The nutrient removal efficiency was similar in the rush/bulrush, bur-reed/cattails and agronomic plant systems. Mean mass removal of N was 94 % at the loading rate of $3kg\;N\;ha^{-1}\;day^{-1}$ and decreased to 71% at the higher rate of $10kg\;N\;ha^{-1}\;day^{-1}$. The two years means for above-ground dry matter production for rush/bulrushes and bur-reed/cattails was l2 and $33Mg\;ha^{-1}$, respectively. Flooded rice yield was $4.5Mg\;ha^{-1}$ and soybean grown in saturation culture yielded $2.8Mg\;ha^{-1}$. Additionally, the performance of seven soybean cultivars using SSC in constructed wetlands with swine wastewater as the water source was evaluated for two years, The cultivar Young had the highest yield with 4.0 and $2.8Mg\;ha^{-1}$ in each year, This indicated that production of acceptable soybean yields in constructed wetlands seems feasible with SSC using swine lagoon liquid. Two microcosms studies were established to further investigate the management of constructed wetlands. In the first microcosm experiment, the effects of swine lagoon liquid on the growth of wetland plants at half (about 175 mg/l ammonia) and full strength (about 350 mg/l ammonia) was investigated. It was concluded that wetland plants can grow well in at least half strength lagoon liquid. In the second microcosm experiment, sequencing nitrification-wetland treatments was studied. When nitrified lagoon liquid was added in batch applications ($48kg\;N\;ha^{-1}\;day^{-1}$) to wetland microcosms the nitrogen removal rate was four to five times higher than when non-nitrified lagoon liquid was added. Wetland microcosms with plants were more effective than those with bare soil. These results suggest that vegetated wetlands with nitrification pretreatment are viable treatment systems for removal of large quantities of nitrogen from swine lagoon liquid.

• Korean Journal of Microbiology
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• v.42 no.1
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• pp.26-33
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• 2006

To understand the efficient process of biological nitrogen removal (BNR) system, the structure of bacterial communities in nitrification reactors was analyzed using PCR and terminal restriction fragment length poly morphism (I-RFLP) methods. In this study, we used an advanced treatment system with plotting media, Nutrient Removal Laboratory system, or the rumination type sequencing batch reactor (SBR) system. The terminal restriction fragments of ammonia-oxidizing bacteria (AOB) and other $\beta-proteobacteria$ were observed in all of three BNR systems. The nucleotide sequence analysis of terminal restriction fragments showed that Nitrosomonas and Nitrosolobus were major populations of AOB in SBR system, whereas uncultured $\beta-proteobacteria$ and Cardococcus australiensis were the predominant groups in other two BNR systems. Also the SBR system may be more efficient to enrich AOB. These results indicate that the different structure of bacterial community may be developed depending on the wastewater treatment systems, although the same influent is used.

• Journal of Korean Society of Water and Wastewater
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• v.21 no.3
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• pp.295-303
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• 2007

Nitrogen compounds in municipal wastewater can be divided into biodegradable and nonbiodegradable fractions with biodegradability. Biodegradable nitrogen compounds can be removed through biological nitrification and denitrification processes, and nonbiodegradable nitrogen compounds affect the effluent quality of biological nutrient removal processes. The amount of nitrifiable nitrogen compounds, which are the sum of ammonia and biodegradable organic nitrogen, has been estimated by respirometry. Respirometry shows good estimation of the concentration of nitrifiable nitrogen when a synthetic sample of ammonium chloride is dosed. The estimated concentration of nitrifiable nitrogen compounds in municipal wastewater is close to ammonia concentration in municipal wastewater, but it is lower than that for the synthetic sample. If nitrogen assimilated into cell synthesis of nitrifiers and heterotrophs is considered, the total amounts of nitrifiable nitrogen compounds, which are nitrified and assimilated, could be more accurately estimated. The concentration of nitrifiable nitrogen compounds, which are biodegradable, is about 31 mg N/l, and this is 119% of ammonia and 94% of total nitrogen. Ammonia, nitrate, biodegradable organic nitrogen, and nonbiodegradable nitrogen are about 79%, 1%, 15%, and 5% of the total nitrogen in municipal wastewater, respectively.

• Journal of Korean Society on Water Environment
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• v.25 no.6
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• pp.872-878
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• 2009

Advanced Phase Isolation Ditch (APID) process was studied to develop economic retrofitting technology, for the plants where retrofitting of common activated sludge process is required. In this study, to develop and apply the modified intermittently aeration mode as process control conditions for treating municipal wastewater, a demonstration plant was installed and operated in the existing sewage treatment plant of P city. During this study, the average effluent $BOD_5$, SS, T-N, and T-P concentrations were 6.3, 4.5, 10.0, and 1.3 mg/L. The modified mode decreased the nitrification capability more than the conventional mode in the application period. Nitrate in the anaerobic condition can have a negative effect on biological phosphorus removal. In the decreasing nitrate levels, the modified mode increased the biological ability of removal phosphorus more than the conventional mode in this study. Therefore, newly developed APID process with modified intermittent aeration mode can be one of the useful processes for stable organic matter and nutrients removal.

• Journal of Environmental Science International
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• v.16 no.7
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• pp.813-821
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• 2007

Laboratory scale experiments were conducted to investigate the removal characteristics of nitrogen and phosphorus in two sequencing batch biofilm reactors (SBBRs). SBBR1 had a short first non-aeration period and SBBR2 had a long first non-aeration period. The removal characteristics of nitrogen and phosphorus in each SBBR were precisely observed according to the variation of influent TOC concentration, and the operation control parameters (pH, DO concentration, ORP) in each reactor were measured. In biological nitrogen removal, there was little difference between SBBR1 and SBBR2 and the nitrogen removal efficiencies were very low. The nitrogen and phosphorus removal characteristics in high influent TOC concentration were different from those in low TOC. Nitrogen removals by simultaneous nitrification/denitrification (SND) were occurred in both SBBR1 and SBBR2. The P removal in SBBR1 was superior to that in SBBR2. The second P release was observed in SBBR1 which had long second non-aeration period.

• Journal of Environmental Health Sciences
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• v.31 no.2 s.83
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• pp.152-159
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• 2005

Laboratory scale experiments were conducted to study the applicability, and to compare the performance of two types of sequencing batch reactor (SBR)systems, a conventional SBR and sequencing batch biofilm reactor (SBBR) on the biological nitrogen and phosphorus removal. The nitrification rate in SaR was higher than that in SBBR both in high influent TOC concentration. The denitrification was completed at the first non-aeration period in SBR, however, the additional non-aeration period should be installed or the first aeration period should be extended more in order to complete the nitrogen removal in SBBR. The time at the first aeration period was more needed as about 4-5 h in order to uptake all the released $PO_4^{3-}\;-P$ at the first non-aeration period. SBBR needed more operation time, especially the first aeration time, than SBR at the high influent TOC concentration in order to complete nitrogen and phosphorus removal.