• 제어로봇시스템학회:학술대회논문집
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• 1993.10a
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• pp.772-777
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• 1993

This paper presents a neuro-fuzzy modelling method that determines chemicals dosing model based on historical operation data for effective water quality control in water treatment system and calculates automatically the amount of optimum chemicals dosing against the changes of raw water qualities and flow rate. The structure identification in the modelling by means of neuro-fuzzy reasing is performed by Genetic Algorithm(GA) and Complex Method in which the numbers of hidden layer and its hidden nodes, learning rate and connection pattern between input layer and output layer are identified. The learning network is implemented utilizing Back Propagation(BP) algorithm. The effectiveness of the proposed modelling scheme and the feasibility of the acquired neuro-fuzzy network is evaluated through computer simulation for chemicals dosing control in water treatment system.

• Proceedings of the KIEE Conference
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• 1995.07b
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• pp.766-768
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• 1995

This paper presents the applied example of "A" city about optimum of chemicals imjection rate. The water treatment plant of "A" city make raw water into drinking water according to the injection of PAC, Alkali and chlorine. Computer performs multiple regression analysis about preoperation data, DCS has been done chemicals optimun control.

• Journal of Korean Society of Water and Wastewater
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• v.21 no.3
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• pp.341-348
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• 2007

The efficiency of powdered activated carbon (PAC) for removing taste and odor (T&O) in drinking water supplies is dependent on the contact time, quality of mixing, and the presence of competing compounds. All of these are strongly influenced by the stage in the treatment process at which the PAC is added. In conventional water treatment plants (WTPs), PAC is commonly added into the rapid mixing basin where chemicals such as coagulants, alkaline chemicals, and chlorine, are simultaneously applied. In order to prevent interference between PAC and other water treatment chemicals, alternative locations for addition of PAC, such as at transmission pipe in the water intake tower or into a separated PAC contactor, were investigated. Whatever the location, addition of PAC apart from other water treatment chemicals was more effective for geosmin removal than simultaneous addition. Among several combinations, the sequence 'chlorine-PAC-coagulant' produced the best result with respect to geosmin removal efficiency. Consequently, when PAC has to be applied to cope with T&O problems in conventional WTPs, it is very important to prevent interference with other water treatment chemicals, such as chlorine and coagulant. Adequate contact time should also be given for adsorption of the T&O compounds onto the PAC. To satisfy these conditions, installation of a separated PAC contactor would be the superior alternative if there is space available in the WTP. If necessary, PAC could be added at transmission pipe in the water intake tower and still provide some benefit for T&O treatment.

• Journal of Korean Society of Water and Wastewater
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• v.18 no.6
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• pp.715-723
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• 2004

The quantity of residuals generated from water treatment plants depends upon the raw water quality, dosage of chemicals used, performance of the treatment process, method of sludge removal, efficiency of sedimentation, and backwashing frequency. Sludge production by the physical separation of SS occurs under quiescent conditions in the primary clarifier, where suspended solids are allowed to settle and to consolidate on the clarifier bottom. Raw primary sludge results when the settled solids are hydraulically removed from the tank. The relative solid and liquid fractions of a slurry are most commonly described by the solids concentration, expressed as mg/L or percent solids. The purpose of the present investigation is to estimate a suitability on the design capacities of residuals treatment facilities by the quantity of dewatered sludge generated from water treatment plants.

• Journal of Environmental Health Sciences
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• v.22 no.3
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• pp.116-122
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• 1996

This study has been focused on the applicability of microwave treatment of soil contaminated by volitile organic chemicals. Substrates studied were sand and sandy soil. These substrates were impregnated with toluene, tetrachloroethylene, o-xylene and p-dichlorobenzene. The microwave treatment was conducted in a modified domestic microwave oven: 2450 MHz, 700 W. The sandy soil temperature added water went up rapidly to about 130$\circ$C for 4 minutes. And then, the temperature appeared to plateau out. A series of tests were performed to depict the effectiveness of microwave treatment technique to organic contaminants from soils. Removal efficiencies in sandy soil and sand were increased with increasing water content and exposure time. Microwave radiation penetrates the soil and heats water throughout the matrix. Therefore, addition of a certain amount of water to the contaminated soil can efficiently enhance the ability of the soil to absorb microwave energy and promote the evaporation of the volitile contaminants. And the vapour pressure of impregnated organic contaminants becomes lower. the removal efficiency becomes poor.

• Journal of Korean Society on Water Environment
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• v.20 no.5
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• pp.432-436
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• 2004

The principle and methodology of risk assessment was applied to establish the quality standard of potential impurities of drinking water treatment chemicals. The impurities(arsenic, lead, cadmium, chromium, mercury, etc.) are regulated as the contained quantity of chemicals in Korea while they are regulated as the quality standard with the idea of 10% of the national safety drinking water standard in U.S.A(NSF) and Japan(JWWA). According to risk assessment of the current standard implemented in Korea, the excess cancer risk of arsenic and lead were determined in around $10^{-5}$ and the hazard quotient(HQ) of cadmium and chromium were below $10^{-2}$, respectively. And the standard concentration of the impurities are regulated as much as 2%~6% of the national drinking water quality standard. The values are more enforced rather than the standards in U.S.A(NSF) and Japan(JWWA) regulating the concentration of impurities the 10% of the national drinking water quality standard. We conclude that the impurities standard of drinking water treatment chemicals should be reconsidered comprehensively concerning the national safety drinking water quality standard and risk assessment.

• Journal of Korean Society of Water and Wastewater
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• v.28 no.4
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• pp.479-489
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• 2014

Membrane backwashing waste shows seasonally different characteristics and it has bad settleability differently from general backwashing waste in water treatment plant. When chemicals was injected to membrane backwashing waste, the settleability was better than chemicals was not injected. However, when settled lower sludge was not discharged, flowing sludge continuously was concentrated over a certain surface and floatation penomena occurred according to flowing velocity. When the lower sludge was discharged continuously in the thickener to prevent floatation penomena of turbidity materials, the depth of sludge surface was the least and the settleability increased.

• Journal of the Microelectronics and Packaging Society
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• v.10 no.4
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• pp.65-71
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• 2003

A new type of ultrasonic spray nozzle was fabricated employing a piezoelectric device. The spray nozzle was designed to disperse chemicals in a water treatment mixing tank. The piezoelectric properties in ultrasonic spray nozzles were optimized to improve the dispersion of chemicals. The piezoelectrics were packaged in an aluminum case with silicone resin for the aqueous solution proof packaging. Chemicals were dispersed with high efficiency and the chemicals consumption was reduced by the ultrasonic fine particle spraying. The concentration of Escherichia coli in mixing tank was decreased remarkably using ultrasonic spray nozzle dispersion compared to the conventional methods.

• Journal of Environmental Health Sciences
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• v.37 no.2
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• pp.113-123
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• 2011

Objectives: Industrial development in Korea results in a rapid increase in the number of chemicals, some of which may be responsible for toxicity to aquatic ecosystems. In addition, the types of hazardous chemicals included in industrial effluents have gradually increased. Therefore, chemical analysis alone is not enough to assess ecological effects of toxic chemicals in wastewater. Methods: In response to new regulations as whole effluent toxicity (WET) tests for effluent discharge of 15 publicly owned treatment works (POTWs) and 25 industrial effluent treatment plants in Gyeonggi-do, which will be effective from 2011, a necessity of studies emerges that investigates toxicity levels. Results: In case of the public treatment plants, none of them had exceeded the criteria for ecotoxicity. As for individual wastewater discharge facilities, on the other hand, two types were found to exceed the criteria: pulp and paper manufacturing facilities and pharmaceutical manufacturing facilities. For the pulp and paper manufacturing facilities, monitoring results could not help determine the exact toxicant identification. However, Daphnia magna inhibition effect or death was found to leave white plums, suggesting that suspended solids treated and the polymer used in coagulant dose. In case of pharmaceutical manufacturing facilities, the general water quality parameters cannot affect Daphia magna. However, conductivity and salinity can have an effect to be 14,000 ${\mu}s/cm$, 8.1‰ by salts, respectively. Toxicity Identification Evaluation (TIE) and Toxicity Reduction Evaluation (TRE) procedures results appeared to be effective for identifying toxic compounds in $Cl^{-}$ and $SO_4^{2-}$. Conclusions: It is necessary to develop control measures for water treatment chemicals and salts used for processes such as coagulation in individual wastewater discharge facilities in order to achieve the goal to protect aquatic ecosystems in public waters.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.36 no.4 s.107
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• pp.41-48
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• 2004

To make a basepaper for multipurposed seed paper, old news print (ONP) and mixed office waste paper (MOW), modified and unmodified with a commercial cellulase, were investigated. Each handsheet was applied with different chemicals such as insecticides, germicides and herbicides. The interactions behaviors of chemicals used with base papers were evaluated by means of the contents of chemicals impregnation and dissolving behaviors in water and soil. The ONP and MOW treated with the cellulase had higher impregnation and dissolving capacities in both water and soil than untreated ONP and MOW. However, the modified ONP showed lower impregnation and dissolving capacities compared to the modified MOW. The content of impregnation of chemicals would be affected with the degree of microfibrils produced by the modification treatment. Otherwise, dissolving capacities of chemicals depend on the affinity of the residual lignin in the paper.