• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.47 no.5
• /
• pp.622-629
• /
• 2014

This study induced biological denitrification and nitrification via a biofiltration process with the view of removing nitrogen from land-based fish farm effluent. To achieve this, we operated an aquaculture nitrogen-removal system that includes a denitrification and nitrification reactor [working volume 40 L, flow rate 64.8 L, HRT (hydraulic retention time) 14.8 h, HRT considering recycling of NOx 7.4 h]. In the continuous process, the nitrification rate of ammonium nitrogen exceeded 90% at a steady state and the denitrification efficiency exceeded 80% with recycling to a pre-anoxic reactor. In addition, the pH in the final effluent was lower with a low influent water alkalinity averaging 100 mg/L (as $CaCO_3$). For effective denitrification reactions, carbon must be supplied via particulate organic matter (POM) hydrolysis because of the low C/N (carbon/nitrogen) ratio in the water.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.31 no.2
• /
• pp.34-41
• /
• 1999

Adsorption of cationic polyacrylamide dry strength resins onto the surface of papermaking fibers and fines is critical for their effective utilization. Since dry strength resins are frequently employed when recycled fibers containing a great deal of fines are used as a raw material, their adsorption characteristic onto the recycled fiber fines is of great importance. In this study, effects of recycling on adsorption characteristics of cationic polyacrylamide onto primary and secondary fines were examined. Never dried bleached hardwood kraft pulp was beaten and dried for recycling. In each recycling step the adsorption characteristic of a cationic PAM onto primary and secondary fines was evaluated by kjeldahl nitrogen analysis method. The influence of recycling on water retention value and carboxyl content along with the sheet density and tensile strength was examined. Secondary fines of never dried pulp adsorbed twice as much of C-PAM as the primary fines, however, the adsorption capacity of the secondary fines decreased rapidly during the course of recycling and showed lower adsorption capacily than primary fines.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.15 no.1
• /
• pp.149-158
• /
• 2007

To investigate the characteristics of the nitrogen mineralization of oil cakes according to changes in temperature(10, 20, $30^{\circ}C$) moisture(40, 50, 60, 70% of field capacity in loam and 50, 60, 70, 80% of field capacity in sandy loam), mineral nitrogen was measured in soil after incubation for 30 days. In addition, the mineralization in sandy loam and loam which had different soil texture were compared. According to incubating the castor seed, soybean, and rice bran cakes with soil, the higher the temperature and moisture content were, the higher the content of mineral nitrogen was observed. The content of mineral nitrogen was higher in sandy loam than loam. The content of mineral nitrogen was decreased with soil depth increasing and was also higher in sandy loam than loam.

• Journal of Crop Science and Biotechnology
• /
• v.10 no.3
• /
• pp.123-132
• /
• 2007

In this review, we discuss the ways in which our understanding of the controls of nitrogen use efficiency applied to crop improvement has been increased through the development of molecular physiology studies using transgenic plants or mutants with modified capacities for nitrogen uptake, assimilation and recycling. More recently, exploiting crop genetic variability through quantitative trait loci and candidate gene detection has opened new perspectives toward the identification of key structural or regulatory elements involved in the control of nitrogen metabolism for improving crop productivity. All together these studies strongly suggest that in the near future nitrogen use efficiency can be improved both by marker-assisted selection and genetic engineering, thus having the most promise for the practical application of increasing the capacity of a wide range of economically important species to take up and utilize nitrogen more efficiently.

• Korean Journal of Organic Agriculture
• /
• v.20 no.1
• /
• pp.21-36
• /
• 2012

In this study, the assessment of livestock manure nitrogen loading for recycling farming in Yeoju-Gun carried out comparing manure units based on the cultivation areas and the N-amount of manure that are generated from livestock manure. Manure units (MU) are used in the permitting, registration, because they allow equal standards for all animals based on manure nutrient production. An MU is calculated by multiplying the number of animals by manure unit factor for the specific type of animal. The manure unit factor for MU determination was determined by dividing amounts of manure N produced 80kg N/year. In this study, manure unit by nitrogen concentration and amount of animal manure was calculated as follows: Hanwoo multiplied by 0.36, dairy cows multiplied by 0.8. swine multiplied by 0.105. The laying hens and broilers multiplied by 0.0079, 0.0049, respectively. The analysis of liquid manure unit per ha shows that the N loading by LMU is quite different by region. When it comes to nitrogen loading, the LMU per ha of cultivated land in excess of the N-amount was the highest in the Bukne-myeon province with 2.76 MU/ha, which is higher than the appropriate level. The Ganam-myeon province came next with 2.53 LMU. To be utilized as a valid program to build the environmentally friendly agricultural system, diverse measures shall be mapped out to properly determine manure units, evaluate N-loading and to properly manage their nutrient balance of each region.

• Korean Journal of Soil Science and Fertilizer
• /
• v.44 no.5
• /
• pp.788-793
• /
• 2011

To evaluate fertilizer value of animal cadavers for agricultural recycling, fertilizer components of animal cadavers by pig and poultry were investigated using rendering and alkali (KOH) treatment methods. Total nitrogen concentrations in meat waste by pig and poultry using rendering treatment method were 7.80% and 9.30%, respectively. Total nitrogen concentration in meat waste of pig by KOH treatment method was lower than that by rendering treatment method. Organic matter concentrations in meat waste of pig and poultry ranged 87.8~97.4%. Total phosphorus concentrations in bone waste of pig using rendering and KOH treatment methods ranged 5.59~11.18%. Animal cadavers contains nitrogen, phosphorus, potassium and other nutrients essential to plant growth. The results of this study suggest that animal cadavers can supply some of the nutrient requirements of crops and is a valuable fertilizer as well.

• Journal of the Korean Applied Science and Technology
• /
• v.24 no.4
• /
• pp.332-338
• /
• 2007

Based on the experiment results of laboratory scale modified anoxic-oxic process for leachate treatment, biological nitrogen removal program was verified in terms of SS, COD, and TN concentration. These measured water qualities concentration could be predicted by biological nitrogen removal program with $R^2$ of 0.994, 0.987, 0.990, respectively. No error was occurred between water qualities concentration and quite wide range of water qualities concentration (i.e., 50-4200 mg/L) during the modelling. Each unit and final effluent of simulated concentration was kept good relationship with that of measured concentration therefore this biological nitrogen removal program for sewage or wastewater treatment plants has good reliance.

• Korean Journal of Organic Agriculture
• /
• v.8 no.2
• /
• pp.97-110
• /
• 2000

An organic agriculture should be managed by mixed farming in farm unit as a closed recycling system. Due to restricted purchased of fertilizers from outside, organic farmer has to deal with limited amount of nutrient source in farm unit. Especially the supply of the essential nutrient, nitrogen, mostly depends on legumes fixing nitrogen optimizing the site-adapted crop rotation. Dynamics of humus and metabolic plant carbon and active soil carbon compartment in active and passive humuspool by rotation system was explained, and dynamics of potentially mineralizable nitrogen in organic nitrogen and biomass was discussed. It was also discussed comparison of ammonia emission, potential greenhouse effect, primary energy input, acidification potential, CO2 emission between organic and conventional farming, the nitrate-nitrogen dynamic in the soil profile by organic, integrated and conventional farming system. In conclusion, it was suggested for Korean Organic Agriculture that the importance of legumes and green manures in rotation system for increase/maintenance of soil ferfility, and was pointed out the need of investment for environment impact of Korean organic farming implement.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.31 no.1
• /
• pp.57-68
• /
• 2023

In this study, coffee waste was recycled into nitrogen-doped porous carbon fibers as an active material for high-energy EDLC (Electric Double Layer Capacitors). The coffee waste was mixed with polyvinylpyrrolidone and dissolved into dimethylformamide. The mixture was then electrospun to fabricate coffee waste-derived nanofibers (Bare-CWNF), and carbonization process was followed under a nitrogen atmosphere at 900℃. Similar to Bare-CWNF, the as-synthesized carbonized coffee waste-derived nanofibers (Carbonized-CWNF) maintained its fibrous form while preserving the composition of nitrogen. The electrochemical performance was analyzed for carbonized coffee waste (Carbonized-CW)-, carbonized PAN-derived nanofibers (Carbonized-PNF)-, and Carbonized-CWNF-based electrodes in the operating voltage window of -1.0-0.0V, Among the electrodes, Carbonized-CWNF-based electrodes exhibited the highest specific capacitance of 123.8F g^-1 at 1A g^-1 owing to presence of nitrogen and porous structure. As a result, nitrogen-contained porous carbon fibers synthesized from coffee waste showed excellent electrochemical performance as electrodes for high-energy EDLC. The experimental designed in this study successfully demonstrated the recycling of the coffee waste, one of the plant-based biomass that causes the environmental pollution into high-energy materials, also, attaining the ecofriendliness.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.24 no.1
• /
• pp.59-63
• /
• 2016

The objective of this study lies in identifying the applicability of zeolite for the removal of wastewater ammonium and nitrate nitrogens. To this end, the author tracked adsorption variations as seen with the adsorption removal of wastewater ammonium and nitrate nitrogens. As a result, it was indicated that the maximum adsorption of zeolite acting on the adsorption removal of ammonium nitrogen would reach 120mg/g (weight of ammonium nitrogen divided by that of zeolite), and that Langmuir adsorption isotherm explained the adsorption of ammonium and nitrate nitrogens better than Freundlich adsorption isotherm. This means that zeolite makes ion exchanges with adsorbate for unilayer adsorption. It was also indicated that the removal efficiency of ammonium nitrogen with varying pH would be higher in the order of pH7 > pH5 > pH9 > pH3.