• Title/Summary/Keyword: dissolved in water

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Effect of Sludge Characteristics on the Thickening of Bulking Sludge using DAF (Dissolved Air Flotation) (슬러지의 성상이 DAF(Dissolved Air Flotation)를 이용한 팽화 슬러지 농축에 미치는 영향)

  • Kim, Dong-Seog;Park, Young-Seek
    • Journal of Korean Society on Water Environment
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    • v.22 no.1
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    • pp.97-103
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    • 2006
  • Excess sludge treatment and disposal currently represent a rising challenge for domestic or wastewater treatment plants due to economic, environmental and regulation factors. Conventional gravity sedimentation process has been widely used in sludge thickening. The operation method of the process is very simple, but the process requires long detention time for sludge thickening, uses polymers, and shows low sludge thickening efficiency. To solve the problems, we studied on DAF (Dissolved Air Flotation) system. We use bulking sludge of a paper manufacturing plant. The effects of parameters such as SVI (Sludge Volume Index), storage time, initial concentration and wet density of excess sludge were examined. The results showed that the more SVI was low, the more sludge was thickened. As storage time goes by, SVI was increased and thickening performance was deteriorated. In order to improve flotation performance at high concentration, high recycling ratio and pressure did not increase the concentration due to thickening limitation. The addition of 0.8 g/L of loess was increased flotation efficiency of 1.41 times.

Effect of pH Adjustment by CO2 on Coagulation and Aluminum Elution in Water Treatment (CO2 주입에 의한 pH 조정이 정수장 응집효율 및 알루미늄 용출에 미치는 영향)

  • Lee, Gil-Seong;Kim, Min-Chai;Kwon, Jae-Kook;Seo, Gyu-Tae
    • Journal of Korean Society of Environmental Engineers
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    • v.35 no.1
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    • pp.17-22
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    • 2013
  • In this study, a pH control method by carbon dioxide ($CO_2$) was applied to coagulation process in water treatment plant (WTP) to investigate the coagulation efficiency and residual dissolved aluminum when high pH raw water is flowing into the plant during algal blooming. Existing coagulant dose (1 mg/L in raw water) resulted in the pH reduction of 0.0384 by LAS, 0.0254 by PAC, 0.0201 by A-PAC, and 0.0135 by PACS2, respectively. And then the concentration of dissolved aluminum was 0.02 mg/L at pH 7.44, 0.07 mg/L at pH 7.96, 0.12 mg/L at pH 8.16, 0.39 mg/L at pH 8.38 showing the concentration increase with pH in the coagulation process. It was noteworthy that rapid increase was observed at pH above 8.0 next the rapid mixing. Therefore it is necessarily required to control pH below 7.8 in the coagulation process in order to meet drinking water quality standard of aluminum for high pH raw water into WTP, $CO_2$ injection could control pH successfully at about 7.3 even for the raw water of high pH above 8.0. In addition it was found that the pH control by $CO_2$ injection was significantly effective for coagulation in terms of turbidity removal, coagulant dosage, and residual dissolved aluminum concentration.

The characteristic change of water using the wet-plasma (습식 플라즈마에 의한 물의 특성 변화)

  • Lee, Jae-Dong;Park, Hong-Jae;Lee, Dong-Hun;Kim, Young-Ju;Park, Jae-Yoon
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2003.07b
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    • pp.1151-1154
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    • 2003
  • Ultraviolet rays, OH H O radical and $O_3$ produced by the streamer discharge in water are widely used to deactivate microorganisms and remove organic contaminants in water and the dominant factor of these decomposition is the oxidized reaction of hydrogen peroxide and dissolved $O_3$ in water. In this paper, the barrier discharge was used to create plasma in a gas, liquid and solid medium and the electrode with the reactor combined barrier with packed type(BPR) was made as noncontact way against water so that the effect of water characteristic change by the erosion of electrodes exposing in water should be minimized. The active radical and $O_3$ gas generated in plasma region were reacted into the water as electrode so that at the same time a dissolved $O_3$ and hydrogen peroxide were formed in water and The change of pH and conductivity were measured.

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A study on the relationship between concentration of phosphorus, turbidity, and pH in water and soil (물과 토양에서 인의 농도, 탁도 그리고 pH와의 관계에 관한 연구)

  • Min, Young-Hong;Hyun, Dae-Yoeung;Eum, Chul-Hun;Lee, Seung-Ho
    • Analytical Science and Technology
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    • v.24 no.4
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    • pp.304-309
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    • 2011
  • In this research, behaviour of turbidity and phosphorus in water and soil dependent upon pH and a change of water was studied. Phosphorus dissolve rate from turbidity was increased for water if potential of hydrogen was less than pH 4 or more than pH 7. Turbidity release rate from soil was increased with pH. Turbidity release rate from soil was drastically increased for water if potential of hydrogen was more than pH 4. turbidity release rate from soil was stabilized more than pH 6. Dissolved phosphorus was increased from 2 hours to 24 hours and stabilized in 24 hours. Turbidity was reached the peak of 24 hours and decreased from 24 hours to 96 hours. Turbidity and dissolved phosphorus was decreased for water if these samples were changed a overlying water. Behaviour of turbidity was analogous to dissolved phosphorus when potential of hydrogen was increased from pH 6 to pH 10 and a change of overlying water was increased from 1 time to 4 times. These results suggest that phosphorus dissolve rate and turbidity were directiy correlated with pH. These results are of great importance in lakes because most lakes have a pH in the range of pH 7-10.

Early Summer Dissolved Oxygen Characteristics in Restored Streams in Seoul (서울시 복원하천들의 초여름 용존 산소량 특성 분석)

  • Thoenen, Casey;Choi, Woonsup;Choi, Jinmu
    • Journal of the Korean Geographical Society
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    • v.48 no.3
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    • pp.336-347
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    • 2013
  • This paper presents an evaluation of stream restoration projects in Seoul with a focus on dissolved oxygen. Five test sites across four streams were measured for dissolved oxygen (DO) in late May to early June in 2012 and compared against a set of minimum and maximum thresholds. Only one test site, Hwarang-cheon, showed measurements below 6 mg/l DO. Towards the upper limit, the Hwarangcheon site was the only tested stream which was not at risk of DO supersaturation. The Danghyeon-cheon site had the highest probability of supersaturation, with DO saturation exceeding 130% expected 86.5% of the time. When measured every hour during daytime, DO levels showed diurnal variations, peaking in the afternoon. However, they showed inconsistent results along transects of the streams. Overall, the streams are rich in DO. To maintain the streams in good standing, nutrient loading should be addressed to prevent potential algal bloom induced hypoxic events down the line.

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Phosphorus removal by lime-natural mineral dissolved solutions

  • Joohyun, Kim;Sunho, Yoon;Jueun, Jung;Sungjun, Bae
    • Membrane and Water Treatment
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    • v.14 no.1
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    • pp.27-33
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    • 2023
  • In previous studies, solely ferric (Fe3+) and calcium (Ca2+) ions were commonly used for removal of PO4-P (considered as T-P in this study) in wastewater via chemical precipitation. Herein, the removal of total phosphorus (T-P) in wastewater was performed using various mineral and lime dissolved solutions. The dissolution kinetics of different minerals (feldspar, olivine, elvan, illite, sericite, and zeolite) and lime was compared and used their solutions for T-P removal of real wastewater. The highest T-P removal (almost 90%) was obtained by the lime dissolved solution and followed by zeolite, illite, feldspar, and others. We observed a significant co-relationship (R of 0.96) between the amount of initial Ca2+ and T-P removal. This was induced by formation of hydroxyapatite-like mineral via Ca-P precipitation reaction at high pH solution. Furthermore, additional removal of suspended solid (SS) and chemical oxygen demand (COD) was achieved by only lime dissolved solution. Finally, the lime-feldspar dissolved solutions were prepared at different ratios (10-50%), which showed a successive T-P removal up to two times by samples of 40 and 50%.

Effects of Dissolved Organic Nitrogen on the Growth of Dominant Phytoplankton in the Southwestern Part of East Sea in Late Summer (늦여름 동해 남서해역에서 용존 유기 질소가 우점 식물플랑크톤의 생장에 미치는 영향)

  • Kwon, Hyeong-Kyu;Jeon, Seul-Gi;Oh, Seok-Jin
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.22 no.1
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    • pp.42-51
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    • 2016
  • We investigated the distribution of dissolved nutrients, phytoplankton community structure and utilization of nitrogen compounds by dominant species in the southwestern part of East Sea in September, 2014. Dissolved inorganic nitrogen (DIN) and dissolved inorganic phosphorus (DIP) were lower in the surface layer, and concentrations were increased with depth. Dissolved organic nitrogen (DON) and dissolved organic phosphorus were the opposite of dissolved inorganic nutrients. Although DIN DIP ratio in all of the water masses was higher than Redfield ratio (16), DIN : DIP ratio in mixed layer was about 2, indicating that inorganic nitrogen is the limiting factor for the growth of phytoplankton. In particular, DON proportion in dissolved total nitrogen was about 88 % in the mixed layer where inorganic nitrogen is limiting factor. The dominant species Chaeotceros debilis and Prorocentrum minimum were able to grow using DIN as well as DON such as urea and amino acids. Therefore, DON utilization of phytoplankton may play a role as a survival strategy in the DIN-limited conditions of East Sea.

Analysis of Sediment Nutrients as Potential Sources of the Lake Water Quality (퇴적물 토양의 영양염류가 호소 수질에 미치는 잠재 요인 분석)

  • Jung, Joon-Oh;Kim, Young-Woo
    • Journal of Environmental Health Sciences
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    • v.35 no.5
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    • pp.376-385
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    • 2009
  • The characteristics of Lake Cheonhoji water and sediment were investigated in oder to utilize these as fundamental materials for the management of lake water quality. The hydrographic properties of Lake Cheonhoji which are relatively low chance of nutrients loading from the watershed and a long retention time of lake water, lead to the probability of high lake productivity. It was also observed that lake water showed stratification during summer and complete mixing during fall, even though water depth was relatively shallow. The trophic state was eutrophic to hypertrophic from summer to late fall. The overall properties of the sediment were oligohumic, high ignition loss and high composition of NAIP and Resid.-P, which might serve as potential pollution sources of lake water quality. In laboratory scale experiments, it was observed that leaching potential of nutrients in the sediment was greatly dependant upon water temperature and dissolved oxygen. Finally, water pollution in Lake Cheonhoji was considered to be largely due to the adverse cycle of uncontrollable eutrophication, which resulted in the subsequent occurrence of dead algae and animal plankton, organic sedimentation, reduction of dissolved oxygen and nutrients leaching, which again reinforced the cycle of eutrophication in the lake.

Low-cycle fatigue behaviors of 316L austenitic stainless steel in high temperature water: Effects of pre-soaking, dissolved oxygen, and boric acid & lithium hydroxide

  • Xiong, Yida;Watanabe, Yutaka;Shibayama, Yuki;Zhong, Xiangyu;Mary, Nicolas
    • Nuclear Engineering and Technology
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    • v.54 no.9
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    • pp.3215-3224
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    • 2022
  • Latest studies found that for 316LN austenitic stainless steel (ASS), its LCF life decreased noticeably in high temperature water containing a great amount of dissolved oxygen (DO) (2 ppm DO), compared with that in the water containing 50 or 100 ppb DO. This finding is different from previous studies about ASSs. This study confirmed that the 316L had similar behavior to 316LN. The LCF life of 316L in water containing 1000 ppb DO water was considerably shorter than that in the water containing 50 ppb DO. Addition of boric acid & lithium hydroxide and pre-soaking did not display noticeable effects on the LCF life of this material in the water with 1000 ppb DO, indicating the discrepancy between the latest studies and previous studies was not caused by the boric acid & lithium hydroxide and pre-soaking. This study also confirmed that similar to 316LN, when a certain amount of DO was added into the water, the amount of hydrogen absorbed into the material decreased significantly compared with that when the DO was less than 5 ppb.

Flotation Characteristics of Activated Sludge by Micro-bubbles (미세 기포에 의한 활성슬러지의 부상특성)

  • Kim, Seong-Jin;Kang, Byoung-Jun;Park, Sang-Wook;Lee, Jae-Wook;Jung, Heung-Joe;Kwak, Dong-Heui
    • Journal of Korean Society of Water and Wastewater
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    • v.20 no.4
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    • pp.501-507
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    • 2006
  • Dissolved air flotation (DAF) has been well known for the gravity separation process. The solids to be separated are transferred from the water body to the water surface using micro-air bubbles. DAF has also been used for enhancing solids-liquid separation of industrial and municipal wastewater by adding a its unit parallel to a sedimentation unit to reduce the hydraulic loading in the sedimentation clarifier. This study was to investigate flotation characteristics of activated sludge by the recent DAF technique without chemical agents. In addition, the effect on temperature in flotation of activated sludge and the thickening degree of activated sludge were studied.