• Clean Technology
• /
• v.27 no.1
• /
• pp.33-38
• /
• 2021

Demand for lithium-based secondary batteries is greatly increasing with the explosive growth of related industries, such as mobile devices and electric vehicles. In Korea, there are several top-rated global lithium-ion battery manufacturers accounting for 40% of the global secondary battery business. Most discarded lithium secondary batteries are recycled as scrap to recover valuable metals, such as Nickel and Cobalt, but residual wastes are disposed of according to the residual lithium-ion concentration. Furthermore, there has not been an attempt on the possibility of water discharge system contamination due to the concentration of lithium ions, and the effluent water quality standards of public sewage treatment facilities are becoming stricter year after year. In this study, the as-received waste water generated from the cathode electrode coating process in the manufacturing of high-nickel-based NCM cathode material used for high-performance and long-term purposes was analyzed. We suggested a facile recycling process chart for waste water treatment. We revealed a correlation between lithium-ion concentration and pH effect according to the proposed waste water of each recycling process through analyzing standard water quality tests and daphnia ecological toxicity. We proposed a realistic waste water treatment plan for lithium electrode manufacturing plants via comparison with other industries' ecotoxicology.

• Membrane and Water Treatment
• /
• v.8 no.3
• /
• pp.279-292
• /
• 2017

This study was aimed at ultrafiltration (UF) as a pretreatment before reverse osmosis (RO) within the scheme of hybrid reverse osmosis-multistage flush (RO-MSF) desalination. Seawater at elevated temperature (after MSF heat-exchangers) was used as a feed in this process. The pretreatment system was represented as a set of functionally-linked technological segments such as: UF filtration, backwashing, chemical- enhanced backwashing, cleaning, waste disposal, etc. The process represents the sequences of operating cycles. The cycle, in turn, consists of the following unit operations: filtration, backwashing and chemical-enhanced backwashing (CEB). Quantitative assessment was based on the following indicators: normalized permeability, transmembrane pressure, specific energy and water consumption, specific waste generation. UF pre-treatment is accompanied by the following waste streams: $W1=1.19{\times}10$ power of $-2m^3$ (disposed NaOCl with 0.0044% wt.)/$m^3$ (filtrate); $W2=5.95{\times}10$ power of $-3m^3$ (disposed $H_2SO_4$ with 0.052% wt.)/$m^3$(filtrate); $W3=7.26{\times}10$ power of $-2m^3$ (disposed sea water)/$m^3$ (filtrate). Specific energy consumption is $1.11{\times}10$ power of $-1kWh/m^3$ (filtrate). The indicators evaluated over the cycles with conventional (non-chemical) backwashing were compared with the cycles accompanied by CEB. A positive impact of CEB on performance indicators was demonstrated namely: normalized UF resistance remains unchanged within the regime accompanied by CEB, whereas the lack of CEB results in 30% of its growth. Those quantitative indicators can be incorporated into the target function for solving different optimization problems. They can be used in the software for optimisation of operating regimes or in the synthesis of optimal flow- diagram. The cycle characteristics, process parameters and water quality data are attached.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2005.04a
• /
• pp.397-401
• /
• 2005

Acid mine drainage and waste of abandoned mine area have caused serious water pollution and destruction of an ecosystem because of exposing to environment without an appropriate treatment. Gwang-yang mine area also has a serious problem in the nearby residential area and waterway ecosystems. The objectives of this research are to develop the most suitable remediation system for acid mine drainage by using waste materials, and to diagnose stream environments impacted by acid mine drainage through the new ecological health assessment methodology, and thus ultimately providing a restoring methodology to mining regions. In the water system health assessment, the result of ESHI model, RBP and Karr suggested by US EPA is revised by ecological features of our country, come to ESHI score 13; 'Very poor' at some points. Together with pH value and heavy metal concentration, it's the aggravation of ecological health index caused by chemical disturbances. In the acid mine drainage treatment, we apply marine shells and slags to this system. Slags had the best removal ability for heavy metals, but pH value was more than 10 exceeding the standard for drain water. In case of marine shells, pH of treated water maintained 7 to 8, and concentrations of Fe and Zn decreased significantly after treatment.

• Transactions of the Korean hydrogen and new energy society
• /
• v.19 no.2
• /
• pp.145-155
• /
• 2008

This paper deals with an economic evaluation of hydrogen production by fermentation. We evaluate the economic feasibility of domestic hydrogen production by fermentation utilizing glucose and waste water sludge in terms of hydrogen production prices. In addition, we make some sensitivity analysis of hydrogen prices by changing the values of input factors such as the price of glucose, the capital cost of the hydrogen production system, and the hydrogen production yields. The estimated hydrogen prices of the two-step dark-light hydrogen production by fermentation utilizing glucose was $5,347won/kgH_2$, and the single-step hydrogen production by anaerobic fermentation utilizing waste water sludge was $4,255won/kgH_2$, respectively. It is expected that the hydrogen production price by anaerobic fermentation can be reduced if we produce methane or hydrogen utilizing by-products such as alcohols and organic acids, or the government imposes some legal regulations on the treatment of waste water sludge.

• Journal of Environmental Health Sciences
• /
• v.29 no.1
• /
• pp.51-61
• /
• 2003

Pollution purification using titanium dioxide (TiO$_2$) photocatalyst has attracted a great deal of attention with increasing number of relent environmental problems. Currently, the application of TiO$_2$ photocatalyst has been focused on purification and treatment of waste water. However. the use of conventional TiO$_2$ powder photocatalyst results in disadvantage of stirring during the reaction and of separation after the reaction. And the usage of artificial UV lamp has made the cost of photocatalyst treatment system high. Consequently, we herein studied the pilot-scale design to aid in optimization of the energy-saving process for more through development and reactor design by solar light/UV lamp/ TiO$_2$system. In this study, we manufactured the TiO$_2$sol by sol-gel method. According to analysis by XRD, SEM and TEM, characterization of TiO$_2$ sol were nano-size (5-6 nm) and anatase type. Inorganic binder (SiO$_2$) was added to TiO$_2$ lot to be coated for support strongly, and support of ceramic bead was used to lower separation rate that of glass bead The influences were studied of various experimental parameters such as TiO$_2$ quantity, pH, flow rate. additives, pollutants concentration, climate condition and reflection plate by means of reaction time of the main chararteristics of the obtained materials. In water treatment system, variable realtor as solar light/ or UV lamp according to climate condition such as sunny and cloudy days treated the phenol and E-coli(Escherichia coli) effectively.

• Journal of Environmental Health Sciences
• /
• v.44 no.1
• /
• pp.55-62
• /
• 2018

Objectives: This study set out to measure the heavy metal concentrations in waste water produced in the casting pickling process at dental technical laboratories and examine the actual state of its treatment. Methods:The investigator measured the concentrations of each heavy metal at 55 dental technical laboratories using an inductively coupled plasma optical emission system. Results: The annual usage of electrolytes was under 10 L in 50 (90.9%), and was 10L or more in five (9.1%) laboratories. Among the laboratories, 15 (27.3%) commissioned the treatment of waste,12 (21.8%) treated the waste with general sewage,and 28 (50.9%) treated the waste in aseptic tank. The arithmetic $mean{\pm}standard$ deviation and the geometric mean of chrome(Cr) were $75.3{\pm}50.9$ and 58.3 mg/L; those of cobalt (Co) were $112.3{\pm}106.7$ and 66.1 mg/L; those of nickel (Ni) were $62.9{\pm}83.5$ and 8.9 mg/L; those of molybdenum (Mo) were $17.1{\pm}13.4$ and 12.0 mg/L; those of iron (Fe) were $31.5{\pm}44.1$ and 6.2 mg/L; those of lead (Pb) were $0.3{\pm}0.3$ and 0.3 mg/L; those of beryllium (Be) were $3.6{\pm}3.6$ and 2.0 mg/L. The hydrogen ion concentration was under pH 2 across all the samples. Conclusions: The findings show that the dental technical laboratories were not doing well with the separation, storage, collection, and treatment of the electrolytes they discarded, and that most of the electrolytes were introduced through the general sewage or aseptic tank. The causes of this include alack of perception among the practitioners at dental technical laboratories and contracted companies avoiding collection for economic reasons. There is a need for education to improve the perceptions of waste water treatment among the practitioners at dental technical laboratories. Environment-related departments should be stricter with legal applications in the central and local governments. It is also required to provide proper management of commissioned treatment.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.23 no.12
• /
• pp.169-175
• /
• 2009

Microbial fuel cell (MFC) is a device to produce a electricity from the oxidation of organic materials using microorganism. Recently many researchers have been studying MFC which is focused as regeneration energy source. Previews studies have focused every each factor that influence the production of electric power. However they didn't study a lot about the correlation among the factors. In order to improve the MFC, we analysed the factors which influencing the generation of electric power of MFC. Also, we made a new compartment to verify the correlations among the factors efficiently. Based on the result obtained from the experiments in the laboratory, we analysed the factors and we suggested a new concept of waste water treatment system to produce electrical energy during the treatment of waste water.

• Journal of environmental and Sanitary engineering
• /
• v.15 no.3
• /
• pp.31-36
• /
• 2000

Conventional membrane systems was difficults to treatment for the swine waste water. Technological advances in membrane filtration systems have created opportunity for the swine wastewater to treat effluent streams in order to meet stricter environmental constraints. "Vibratory Shear Enhanced Processing(VSEP)" developed by new logic international makes it possible to filter effluent streams without the fouling problem exhibited by conventional membrane systems. Various kinds of waste water occurred to and swine wastewater experiment with "VSEP" set up conventional reverse osmosis membrane (ACM-4, ESPA, BW-30). The results were as followes : Treatment efficiency for the input COD(From $332mg/{\ell}$ to $4,968mg/{\ell}$) was 98%. Treatment efficiency for the input SS(From $140mg/{\ell}$ to $4,040mg/{\ell}$) was 100%(All together). Treatment efficiency for the input T-N(From $155mg/{\ell}$ to $934mg/{\ell}$) was 97%~99.8%. Treatment efficiency for the input T-P(From $28.6mg/{\ell}$ to $132mg/{\ell}$) was 99.7% and up. ESPA membrane excels three types of reverse osmosis membranes applied VSEP in removal efficiency.

• Journal of the Institute of Convergence Signal Processing
• /
• v.16 no.3
• /
• pp.108-114
• /
• 2015

Ballast water is carried by ships to ensure stability, trim and structural integrity. When a ship loads cargo, the ballast water is discharged. When foreign marine microorganisms are introduced into new marine environments, they pose a threat to the local marine ecological system. UV system is commonly used for the disinfection of waste and surface water. This method would not be as efficient because some species do survive to form viable populations, much of the sediment and organisms at the bottom of tanks, and may become serious pests. In this paper, we designed and implemented ballast water treatment system using fuzzy PID controller to prevent lamp damage, and to reduce the formation of the viable populations. The experiments were conducted with ballast water treatment system using fuzzy PID controller with short time exposure to the temperature above $40^{\circ}C$. This system was shown to be effective by significantly reducing bacterial population and lamp life extension through appropriate temperature of ballast water.

• Korean Journal of Soil Science and Fertilizer
• /
• v.26 no.2
• /
• pp.127-131
• /
• 1993

A newly developed waste-water treatment system for small scale piggery wastes through a demonstration trial at a farm. The results are summarized as follows. 1. The amount of piggery wastes produced was 10.2kg/head/day, which consisted of 2.8kg solid wastes and $7.41{\ell}$ fluid wastes. 2. The unit BOD discharge from piggery wastes was 207g/head/day, among which 81 percent was originated from solid waste and 19 percent from fluid waste. 3. After the treatment of the waste-water through the system, BOD, total N and total P were lowered by 99, 78, 74 percent, respectively : the BOD, total N and total P in the final effluent were $52mg/{\ell}$, $213mg/{\ell}$ and $28mg/{\ell}$, respectively. 4. The results of the trials suggested that the system could be recommended for the practical use at the farms.