• Journal of Korean Society on Water Environment
• /
• v.38 no.6
• /
• pp.282-291
• /
• 2022

Since the efficiency of wastewater treatment using microalgae differs depending on the metabolic characteristics of the species, it is important to understand the characteristics of target algae prior to the application in wastewater treatment. In this study, for the application of Arthrospira platensis to wastewater treatment, which is a filamentous alkaliphilic cyanobacteria, basic species specificity was identified and the possibility of application to wastewater treatment was investigated. As a result of the species specificity investigation, the specific growth rate between pH 7.0 and 11.0 showed the highest value near pH 9 at 0.25/day. The reason for the relatively low growth(0.08/day) at pH 11 was thought to be the CA(carbonic anhydrase) enzyme that is involved in carbon fixation during photosynthesis has the highest activity at pH 8.0 to 9.0, and at pH 11, CA activity was relatively low. In addition, A. platensis showed optimal growth at 400 PPFD(photosynthetic photon flux density) and 30℃, and this means that cyanobacteria such as A. platensis have a larger number of PS-I(photosystem I) than that of PS-II(photosystem II). It was speculated that it was because higher light intensity and temperature were required to sufficiently generate electrons to transfer to PS-I. Regarding the applicability of A. platensis, it was suggested that if a system using the synergistic effect of co-culture of A. platensis and bacteria was developed, a more efficient system would be possible. And different from single cocci, filamentous A. platensis expected to have a positive impact on harvesting, which is very important in the latter part of the wastewater treatment process.

• Journal of Korean Society of Water and Wastewater
• /
• v.13 no.4
• /
• pp.27-34
• /
• 1999

An experimental study on improvement of the paper-mill wastewater treatment using the pure oxygen activated sludge process was conducted. The effects of hydraulic retention time(HRT) and BOD loading on organic removal efficiency were investigated. The BOD removal efficiencies were above 90% under all examined HRTs except for HRT of 3 hours. The increase of HRT from 3 hours to 6 hours, and to 12 hours significantly improved BOD and COD removal efficiencies, respectively. However, additional increase of HRT did not affect organic removal efficiency. F/M ratio change at fixed HRT did not affect organic removal efficiency. However, F/M ratio investigated in this study(0.11~1.98kgBOD/kgMLVSS/day) was 5 times greater in maximum than that of conventional activated sludge process, which implies that pure oxygen activated sludge process can treat wastewater with high organic strength. Under the same HRT, the volumetric BOD loading change cause no effect on organic removal efficiency also.

• Journal of Korean Society of Water and Wastewater
• /
• v.28 no.3
• /
• pp.305-314
• /
• 2014

A pilot plant (Q=5 $m^3/d$) study was implemented for small and medium sized personal wastewater treatment plant effluent to evaluate MBR and A/O processes utilizing self-sufficient energy composed of wind and solar energy. The removal efficiencies of BOD, SS, turbidity and color were sufficient for legal water quality standards for gray water. However, those of nitrogen and phosphorus could not meet legal regulations which suggested that further removal of those contaminants were needed for reuse of the treated water. Self-sufficient energy rate was 100 % for the pilot plant due to excessive design capacity. In this research, wind and solar energy system was applied considering geological characteristics, which significantly improved energy self-sufficiency. Substantial improvement on energy self-sufficiency can be obtained by optimized investment and operation at a full scale wastewater treatment plant.

• Journal of Environmental Impact Assessment
• /
• v.16 no.2
• /
• pp.169-176
• /
• 2007

The paved areas in nonpoint source are highly polluted landuses because of high imperviousness and pollutant mass emissions, such as sand, cereals, and dust from vehicle activities. Most of them in highways are collected by cleaning trucks or discharged to the adjacent soil and water system through the drain ditch in stormwater. Therefore, it is necessary to investigate the relationship between water concentration and total pollutant loadings from the paved areas. From the experiment, CODcr concentration of the cleaning wastewater was 17 times greater than that of the stormwater runoff. Also, concentrations of heavy metals (Cu, Fe, Zn) were 1.3 to 1.5 times higher when compared to the stormwater runoff. While total discharged loadings was insignificant in the cleaning wastewater. In conclusion, these results provide some evidence that the stormwater runoff may be managed carefully to the aspect of total pollutant loadings and the cleaning wastewater may be handled cautiously with the pollutant concentrations in highways.

• Journal of Advanced Marine Engineering and Technology
• /
• v.17 no.4
• /
• pp.20-27
• /
• 1993

Emulsified oily wastewater is generally hard to treat in separating oil and water by conventional separators. In this paper the magnetohydrodynamic water treatment device was used to separate oil from emulsified oily wastewater which contained high conductivity. The emulsified oil removal rates and economic ranges of oil separation at various factors were investigated to confirm the influence of the magnetic field in MHD water treatment device according to the characteristics of emulsion brake. Experimental results proved that the oil removal rates were proportional to Lorentz force which depends on the intensity of magnetic field, conductivity and velocity of wastewater.

• Journal of Korean Society of Water and Wastewater
• /
• v.21 no.6
• /
• pp.701-707
• /
• 2007

The information on the incoming load to wastewater treatment plants is not often available to apply to evaluate effects of control actions on the field plant. In this study, a time series model was developed to forecast influent flow rate, BOD, COD, SS, TN and TP concentrations using field operating data. The developed time series model could predict 1 day ahead forecasting results accurately. The coefficient of determination between measured data and 1 day ahead forecasting results has a range from 0.8898 to 0.9971. So, the corelation is relatively high. We made forecasting program based on the time series model developed and hope that the program will assist the operators in the stable operation in wastewater treatment plants.

• Journal of environmental and Sanitary engineering
• /
• v.13 no.3
• /
• pp.85-92
• /
• 1998

In this study, the electrolytic treatment by one-stage electrolysis was investigated for electroplating wastewater containing $Cr^{6+}$ and $CN^{-}$. From the results, we concluded as follows : Optimum initial pH of wastewater was pH : 3. Amount of optimum addition of electroltyte(NaCl) was 0.1 wt%. Optimum potential for electrolysis was 5 volt. Concentration and removal efficiency for $Cr^{6+}$ and $CN^{-}$ were under 1 mg/L and above 99% at optimum conditions. And the feasibility of electrolytic treatment for electroplating wastewater containing $Cr^{6+}$ and $CN^{-}$ was certified.

• Journal of Animal Environmental Science
• /
• v.7 no.2
• /
• pp.77-82
• /
• 2001

This research was carried out to investigate the daily amount and characteristics of wastewater produced from bucket milkers, pipeline, tandem ad herringbone milking system for washing operations after milking included 28 dairy farms. The average amount of wastewater produced from milking system was 9.8l/head/day. The amount of wastewater varied from a low of 8.2 litters/head/day(pipeline milking system) to 13.4 litter/head/day(herringbone milking system). The moisture content, Biochemical Oxygen Demand($BOD_5$), Chemical Oxygen Demand($COD_{Mn}$), Suspended Solids(SS), Total Nitrogen(T-N) and Total Phosphorus(T-P) concentration of wastewater were 99.9%, 394mg/l, 417.3mg/l, 1,201.3mg/l, 3.78mg/l, 0.51mg/l.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 1998.11a
• /
• pp.162-165
• /
• 1998

This research has been made in order to evaluate and characterize wastewater from closed coalmines throughout the country. The characteristics of the wastewater from closed coalmines are affected greatly with geochemical nature and are not changed significantly with the lapse of time. Pollutants concentration profile could be divided into two groups below and above pH of around 5.

• Proceedings of the Membrane Society of Korea Conference
• /
• 2005.05a
• /
• pp.153-156
• /
• 2005