• Environmental Engineering Research
• /
• v.25 no.4
• /
• pp.554-560
• /
• 2020

This study focuses on nitrification through a biological aerated filter (BAF) that is filled with a zeolite medium at low concentrations of ammonia. The zeolite medium consists of natural zeolite powder. The BAF is operated under two types of media, which are a ball-type zeolite medium and expanded poly propylene (EPP) medium. Nitrification occurred in the zeolite BAF (ZBAF) when the influent concentration of ammonia nitrogen was 3 mg L-1, but the BAF that was filled with an EPP medium did not experience nitrification. The ammonia nitrogen removal efficiency of ZBAF was 63.38% and the average nitrate nitrogen concentration was 1.746 mg/L. The ZBAF was tested again after a comparison experiment to treat pond water, and municipal wastewater mixed pond water. The ZBAF showed remarkable ammonia-nitrogen treatment at low concentration and low temperature. During this period, the average ammonia nitrogen removal efficiency was 64.56%. Especially, when water temperature decreased to 4.7℃, ammonia nitrogen removal efficiency remained 79%. On the other hand, the chemical-oxygen demand (COD) and phosphorus-removal trends were different. The COD and phosphorus did not show as efficient treatment as the ammonia-nitrogen treatment.

• Journal of Marine Bioscience and Biotechnology
• /
• v.4 no.1
• /
• pp.1-5
• /
• 2010

With the world's population increase, demands of fish production increased rapidly. Because of the demand increase, methods of aquaculture also become more intense. With the increasing intensity of aquaculture, more metabolites in the system are accumulated. The metabolites accumulated in the system turn to the causatives of water quality deterioration and become limiting factors for fish growth. Due to the toxicity of ammonia, ammonia removal is needed in aquaculture system. Biofilters, often referred as biological filter or nitrification filter are commonly used in recirculating aquaculture system to remove ammonia and convert it to nitrite, and then to nitrate.

• 한국생물공학회:학술대회논문집
• /
• 2005.04a
• /
• pp.65-66
• /
• 2005

Anaerobic digestion is one of the well-known methods for biological treatment handling of concentrated organic matter such as swine $wastewater.^{1)} The anaerobic digestion can reduce organic loading but also hydrolyze non-biodegradable organic $matter.^{2)}$ The feces from the scrapper-type barn are usually collected to make compost and the urine is discarded with swine-slurry wastewater by ocean-dumping or treated by biological methods. The lagoon, aerobic digestion, anaerobic digestion, SBR, $A^{2}/O$, and UCT have been applied for treating swine $wastewater.^{3)} In this study, as a result of the analysis of swine wastewater, the total and soluble chemical oxygen demand was 130g/L and 60g/L, respectively. And the volatile fatty acid as chemical oxygen demand equivalent was 45g/L, which was 75% of soluble chemical oxygen demand. Before everything else, ammonia nitrogen concentration was 6.5 g/L. From biochemical acidogenic potential test, it was concluded that the enhanced acidification process to manage swine waste should be operated in the ammonia nitrogen concentration of less than 1.2 g/L. In the result of seeding ratio experiments with artificial $wastewater^{4)}, the lag period of acidogens was taken the long time because of the inhibition by the $ammonia^{5)}$, however no difference of period by the seeding ratio was not shown. The Haldane-based biokinetics were also evaluated using a method of fourth order Runge-Kutta $approximation.^{6,7)}$ The nonlinear least squares (NLLS) method with a 95% confidence interval was also used. The ranges of maximum microbial growth rate, ${/mu_{max}}$, and half saturation coefficient, $K_{s}$, for acidogenesis of various seeding ratio with artificial wastewater were 6.1 ~ 12.6 $d^{-1}$ and 45,000 ~ 53,500 mg glucose/L, respectively. Also, the methanogenic microbial yield coefficient, Y, and microbial decay rate coefficient, $k_{d}$, and inhibition substrate concentration, $K_{si}$, for the reactors were determined to be 0.32 ~ 0.465 ${/mu}g$/mg glucose; 0.42 ~ 1.01 $d^{-1}$ and 51,500 ~ 55,600 mg glucose/L, respectively.

• Journal of Korean Society on Water Environment
• /
• v.23 no.6
• /
• pp.993-997
• /
• 2007

The upflow anaerobic sludge blanket (UASB) reactor can be effective for treating simple organic compounds containing high concentration of ammonia nitrogen. The chemical oxygen demand (COD) removal efficiency was about 80% at ammonia nitrogen concentration up to 6,000 mg-N/L. This result also showed that it would be possible to treat propionate effectively at free ammonia nitrogen concentration up to 724 mg-N/L if sufficient time was allowed for adaptation. However the specific methanogenic activity (SMA) of granule was lower than that of granule in the reactor with lower ammonia nitrogen concentration. At 8,000 mg-N/L, the inhibition of high ammonia concentration was observed with evidence of increase of the volatile suspended solids (VSS) concentration in the effluent. It might be ascribed to the decrease in the content of extracellular polymer (ECP), which resulted to the sloughing off of obligated proton-reducing acetogens and heterogenotrophic methanogens from the exterior of granular sludge. This caused a great portion of the finely sludge to be easily washed out. Therefore, failure to maintain the balance between these two groups of microorganism cause accumulation of the hydrogen partial pressure in the reactor, which could have inhibited the growth of acetate utilizing methanogens.

• Journal of the Korean Institute of Gas
• /
• v.27 no.3
• /
• pp.11-18
• /
• 2023

This study explained the need for ammonia fuel and the value chain as a hydrogen carrier. The basic concept of ammonia combustion characteristics and the development of flame stability and low NOx combustion technology were introduced. In addition, through the trend of ammonia combustion technology, the characteristics of ammonia combustion technology in the power generation and industrial sectors were examined, and the author's opinions were included. Through this paper, the author intends to give some overview of basic knowledge about ammonia fuel and its future development direction and meaning.

• Korean Journal of Microbiology
• /
• v.10 no.3
• /
• pp.97-104
• /
• 1972

The extent of water pollution was investigated at 4 stations in Kyonggi Bay during the summer seasons in 1970 and 1971. The concentrations of dissolved oxygen, total hardness, ammonia, nitrate, nitrite, phosphate, chemical oxygen demand, salinity, biochemical oxygen demand, coliform bacteria and facel coli were examined together with the measurement of pH and transparency. The relationship between the extent of pollution and the distance from the Inchon Bay also was examined. The concentrations of biochemical oxygen demand, chemical oxygen demand, ammonia, nitrate, nitrite, phosphate, coliform bacteria nad fecal coli were all highest at station 1, and lowest at station 4. Values were somewhat higher at low tide level in general. On the contrary, dissolved oxygen concentration was highest at station 4 and lowest at station 1. The highest and lowest values of biochemical oxygen demand were 10.88 ppm at station 1 and 0.27 ppm at station 4. The chemical oxygen demand concentrations at station 1 and 4 were 1.90 ppm and 0.63 ppm. Ammonia concnetration at station 1 was 0.43 pp, and was nearly 5 times as much as that at station 4. The values were $2.45{\times}10^{-4}$ ppm at station 1, and $6{\times}10^{-4}$ ppm at station 4. Nitrite concnetration at station 1 was $3{\times}10^{-4}$ppm and was the highest, while the lowest was $9.45{\times}10^{-5}$ ppm at station 4. Phosphate value at station 1 too was the highest and was about 4 times as much as that at station 4. Coliform bacteria were most abundant at station 1, and were counted to be 1.$1.7{\times}10^{-5}$cells/ml. At station 4, the number greatly reduced to 8 * 10$^{2}$ cells/ml. The number of fecal coli at station 1 was $2{\times}10^{-4}$ cells/ml. But at station 4, no fecal coli was detected at high tide level. At low tide level, 3 cells/ml were counted at station 4. In all of these, the highest data were obtained at low tide level, while most of the lowest value, at high tide level. Generally, values at statio 1 were 3-5 times as much as those at station 4. Concentration of dissolved oxygen at station 1 was 0.366 mg-atoms/1 and was the lowest. The highest value was 0.420 mg-atoms/1 and was recorded at station 4. The highest at station 4, which certainly were believed to be the result of the dilution by the fresh water of the Han river flowing into the Inchon Bay. As we can see from the data above, the extent of pollution was highest at station 1, the nearest from Inchon harbor, and lowest at station 4, where is the farthest, Station 1 and 2 were proved to be much polluted, but station 3 and 4, not.

• Environmental Engineering Research
• /
• v.24 no.1
• /
• pp.144-149
• /
• 2019

Landfill leachate constitutes one of the most polluting wastewaters. Their treatment was considered difficult due to the presence of high concentration of organic matter, ammonia, toxic organic compounds and heavy metals. Biological processes were found to be effective in several cases, but they are limited by the presence of inhibitory compounds in leachate. In this study we develop a biological process for the leachate biodetoxification using Trametes trogii (T. trogii; CLBE55). Results show that laccase activity, mycelia growth and chemical oxygen demand (COD) removal efficiencies varied depending on the leachate and ammonium concentration. Indeed T. trogii was able to grow in the presence of low concentration of landfill leachate of 10 and 30%. In fact, the biomass produced was 4.7 and 3.7 g/L, respectively leading to a COD removal of 66 and 53%, respectively. However, when the concentration of the introduced leachate exceeds 30%, the treatment efficiency and particularly the COD removal decreases to reach 15% at 100% leachate. The effect of the ammonia was also studied and results showed that the addition of 5 g/L of ammonia inhibited totally the production of laccase and the COD removal.

• Environmental Engineering Research
• /
• v.15 no.2
• /
• pp.79-84
• /
• 2010

Three biological aerated filters (BAFs) composed of a PVC pipe with a diameter of 75 mm were constructed and operated at a waste-water temperature at $13^{\circ}C$. The media used for each BAF were: 5-mm gravel; 5-mm lava rock; 12.5-mm diameter by 15-mm long plastic rings, all with a media depth of 1.7 m. The feedwater, which simulated the effluent of aerated lagoons, had influent soluble chemical oxygen demand (sCOD) and ammonia concentrations of approximately 50 and 25 mg/L, respectively. For a hydraulic retention time (HRT) of two hours without recirculation, ammonia percent removals were 98.5, 98.9, and 97.8%, for the gravel, lava rock, and plastic rings, respectively. By increasing the effluent recirculation from 100 to 200% for an HRT of one hour, respective ammonia removals improved from 90.1 to 96, 76.5 to 90, and 65.3 to 79.5% for gravel, lava rock, and plastic rings. Based on the ammonia and sCOD loadings for different HRTs, the estimated maximum ammonia loading was approximately 0.6 kg $NH_3-N/m^3$-day for the three BAFs of different media types. The zero-order biotransformation rates for the BAF with gravel were found to be higher than the lava rock and plastic ring media. The results ultimately showed that BAF can be used as an add-on system to aerated lagoons or as a secondary treatment unit to meet ammonia discharge limits.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.14 no.3
• /
• pp.126-137
• /
• 2006

Behaviors of simple organic compound and granular sludge in an upflow anaerobic sludge blanket (UASB) reactor treating propionate at high ammonia nitrogen levels were investigated for 12 months. The UASB reactor achieved about 80% removal of chemical oxygen demand (COD) at ammonia nitrogen concentration up to 6000 mg-N/L. At higher concentration of ammonia nitrogen, the propionate in the effluent increased whereas the acetate was very low. At ammonia nitrogen concentration of 8000 mg-N/L, the volatile suspended solids (VSS) increased sharply due probably to the decrease of the content of extracellular polymer (ECP) although methane production was very low. The specific methanogenic activity (SMA) using formate, acetate, and propionate as substrate to granules decreased as ammonia nitrogen concentration increased. The ammonia nitrogen concentration $I^{50}$, causing 50% inhibition of SMA were 2666, 4778 and 5572 mg-N/L, respectively. The kinetic coefficients of ammonia inhibition using formate, acetate, and propionate as substrate were 3.279, 0.999 and 0.609, respectively. The SMA using formate was severely affected by ammonia nitrogen than those using acetate and propionate. This result indicated that the hydrogenotrophic methanogens was most affected by ammonia nitrogen. Granules were mainly composed of microcolonies of methanothrix-like bacteria resembling bamboo-shape, and several other microcolonies including propionate degrader with juxtapositioned syntrophic associations between the hydrogen-producing acetogens and hydrogen-consuming methanogens.

• Advances in Energy Research
• /
• v.4 no.2
• /
• pp.107-120
• /
• 2016

The aim of this research is to apply the eQuest model to investigate the energy conservation in a multifamily building located in Dayton, Ohio by using a Trombe wall and an ammonia ground source heat pump (R-717 GSHP). Integration of the Trombe wall into the building is the first retrofitting measure in this study. Trombe wall as a passive solar system, has a simple structure which may reduce the heating demand of buildings significantly. Utilization of ground source heat pump is an effective approach where conventional air source heat pump doesn't have an efficient performance, especially in cold climates. Furthermore, the type of refrigerant in the heat pumps has a substantial effect on energy efficiency. Natural refrigerant, ammonia (R-717), which has a high performance and no negative impacts on the environment, could be the best choice for using in heat pumps. After implementing the eQUEST model in the said multifamily building, the total annual energy consumption with a conventional R-717 air-source-heat-pump (ASHP) system was estimated as the baseline model. The baseline model results were compared to those of the following scenarios: using R-717 GSHP, R410a GSHP and integration of the Trombe wall into the building. The Results specified that, compared to the baseline model, applying the R-717 GSHP and Trombe wall, led to 20% and 9% of energy conservation in the building, respectively. In addition, it was noticed that by using R-410a instead of R-717 in the GSHP, the energy demand increased by 14%.