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Feng Jiang - One of the best experts on this subject based on the ideXlab platform.

  • removal of heavy metals using a novel sulfidogenic amd treatment system with sulfur reduction configuration performance critical parameters and economic analysis
    Environment International, 2020
    Co-Authors: Yu Li, Chunxi Ou, Xiaoyi Wang, Liang Zhang, Feng Jiang
    Abstract:

    Abstract A novel sulfidogenic acid mine drainage (AMD) treatment system with a sulfur reduction process was developed. During the 220-d operation, >99.9% of 380-mg/L ferric, 150-mg/L aluminum, 110-mg/L zinc, 20-mg/L copper and 2.5-mg/L lead ions, and 42.6–44.4% of 100-mg/L manganese ions in the synthetic AMD were step-by-step removed in the developed system with three pre-posed metal precipitators and a sulfur reduction reactor. Among them, zinc, copper and lead ions were removed by the biogenic hydrogen sulfide that produced through elemental sulfur reduction; while ferric, aluminum and manganese ions were removed by the alkali precipitation. Compared with the reported sulfate reduction reactors, the sulfur reduction reactor significantly reduced the Chemical Cost by 25.6–78.9% for sulfide production, and maintained a high sulfide production rate (1.12 g S2-/L-d). The pH level in the sulfidogenic reactor driven by sulfur-reducing bacteria posed a significant effect on the sulfide production rate. Under a nearly neutral condition (pH 7.0–7.5), elemental sulfur dissolved into polysulfide to increase the bioavailability of S0. At acidic conditions (pH

  • Realizing a high-rate sulfidogenic reactor driven by sulfur-reducing bacteria with organic substrate dosage minimization and Cost-effectiveness maximization.
    Chemosphere, 2019
    Co-Authors: Jiahua Guo, Jinting Wang, Yan-ying Qiu, Jianliang Sun, Feng Jiang
    Abstract:

    Abstract Biological sulfur reduction is an attractive sulfidogenic technology for the treatment of organics-deficient metal-laden wastewater, because it theoretically reduces the electron donor consumption by 75%, compared to sulfate reduction. However, reducing the external organic substrate dosage may lower the sulfur reduction rate. Supplying with a more biodegradable organic substrate could possibly enhance sulfidogenic activity but also increase the Chemical Cost. Therefore, the sulfide production performance of a sulfur-reducing bioreactor feeding with varied levels of organic supply, and different types of organic substrates were investigated. The results showed that high-rate sulfide production (12.30 mg S/L/h) in a sulfur-reducing bioreactor can be achieved at the minimal dosage of organic substrate as low as 39 mg C/L of organic carbon in the influent. Changing the type of organic substrate posed a significant effect on the sulfidogenic activity in the sulfur-reducing bioreactor. Sodium acetate was found to be the optimal substrate to achieve the highest sulfide production rate (28.20 mg S/L/h) by sulfur-reducing bacteria (S0RB), followed by ethanol, methanol, glycerol, pyruvic acid, acetic acid, glucose, sucrose, malic acid, sodium formate, formic acid, N-propanol, N-butanol, lactic acid, sodium lactate, propionic acid and sodium propionate (2.87 mg S/L/h as the lowest rate). However, the Cost-effectiveness analysis showed that glucose was the most Cost-effective organic substrate to realize the sulfur reduction process in high sulfide production rate (20.13 mg S/L/h) and low Chemical Cost (5.94 kg S/$). The utilization pathway of the different organic substrates in the sulfur-reducing bioreactor was also discussed.

Benjamin L. Dow - One of the best experts on this subject based on the ideXlab platform.

  • St. Louis Chemical: Cost of capital.(Instructor's Note)
    Journal of the International Academy of Case Studies, 2011
    Co-Authors: David A. Kunz, Benjamin L. Dow
    Abstract:

    CASE DESCRIPTION The primary subject matter of this case concerns the issues surrounding a firm's weighted average Cost of capital (WACC). Case provides a review of Cost of capital issues. The case requires students to have knowledge of accounting and finance, thus the case has a difficulty level of three (junior level) or higher. The case is designed to be taught in one class session of approximately 1.25 hours and is expected to require 2-3 hours of preparation time from the students. CASE SYNOPSIS The case tells the story of Don Williams, President and primary owner of St. Louis Chemical. By most measures, the performance of St. Louis Chemical has been very good over the last three years, with sales and income increasing each year Business growth has been steady but a recent increase in demand has placed a strain on existing operations. To keep pace with demand, the capacity of the current warehouse and packaging operations need to be increased. The Cost of the facility expansion has been estimated to be $900,000 by St. Louis Chemical's operation manager. Since beginning operations, Williams has been reluctant to borrow funds. He has been content with limited growth, financed with internally generated equity. Recently hired Edison Hesselbach, the company's first finance professional, has recommended borrowing the required funds. Williams indicated he may be willing to consider a change in his long-standing policy against debt, but wants more information regarding using debt in the firm's capital structure. CASE USE The case as written includes discussion questions to aid the student in their analysis of St. Louis Chemical's current situation. The case can be made more difficult by omitting the discussion questions. CASE OVERVIEW As the case opened Don Williams, the President of the St. Louis Chemical, a regional Chemical distributor, headquartered in St. Louis, Missouri, is in need of additional assets and financing to support future growth. To keep pace with demand, the capacity of the current warehouse and packaging operations need to be increased. The Cost of the facility expansion has been estimated to be $900,000 by St. Louis Chemical's operation manager. Williams has also followed a conservative financing policy. Since beginning operations, he has been reluctant to borrow funds, content with limited growth, financed with internally generated equity. The only long-term debt on the company's balance sheet reflects the financing associate with vehicles. If the facility is to be expanded, additional external financing will be necessary. St. Louis Chemical's income statement and balance sheet for the years 2007-2009 are provided in Schedules One and Two, respectively. Hesselbach has recommended borrowing the required funds. Williams indicated he may be willing to consider a change in his long-standing policy against debt, but wants more information regarding the advantages of using debt in the firm's capital structure. Hesselbach, using input from an investment-banking firm, has estimated the company's Cost of equity to be 14%. A St. Louis bank has indicated a long-term bank loan can be arranged to finance expansion at an annual interest rate of 10%. The bank would require either loan to be secured with expansion and other company assets. The loan agreement would also include a number of restrictive covenants, including a limitation of dividends while the loans are outstanding. Only a small amount of long-term debt is included in the firm's current capital structure, the firm's debt ratio at the end of 2009 was 21% and long-term debt was only .28% of total assets (see schedule 2). Hesselbach calculated that if a long-term bank loan was used to obtain the needed $900,000, the firm's debt ratio would increase to 30%. He believes a 30% debt and 70% equity capital mix would be conservative and a starting point for introducing long-term debt into the firm's capital structure. …

  • St. Louis Chemical: Cost of Capital
    Journal of the International Academy of Case Studies, 2011
    Co-Authors: David A. Kunz, Benjamin L. Dow
    Abstract:

    CASE DESCRIPTION The primary subject matter of this case concerns the issues surrounding a firm's weighted average Cost of capital (WACC). Case provides a review of Cost of capital issues. The case requires students to have knowledge of accounting and finance, thus the case has a difficulty level of three (junior level) or higher. The case is designed to be taught in one class session of approximately 1.25 hours and is expected to require 2-3 hours of preparation time from the students. CASE SYNOPSIS The case tells the story of Don Williams, President and primary owner of St. Louis Chemical. By most measures, the performance of St. Louis Chemical has been very good over the last three years, with sales and income increasing each year Business growth has been steady but a recent increase in demand has placed a strain on existing operations. To keep pace with demand, the capacity of the current warehouse and packaging operations need to be increased. The Cost of the facility expansion has been estimated to be $900,000 by St. Louis Chemical's operation manager. Since beginning operations, Williams has been reluctant to borrow funds. He has been content with limited growth, financed with internally generated equity. Recently hired Edison Hesselbach, the company's first finance professional, has recommended borrowing the required funds. Williams indicated he may be willing to consider a change in his long-standing policy against debt, but wants more information regarding using debt in the firm's capital structure. BACKGROUND St. Louis Chemical is a relatively new regional distributor of liquid and dry Chemicals, headquartered in St. Louis, Missouri. The company, founded by Don Williams, has been serving primarily eastern Missouri and western Illinois for four years and has developed a reputation as a reliable supplier of industrial Chemicals. Williams' previous business experience provided him with a solid understanding of the Chemical industry and the distribution process. As a general manager for a Chemical manufacturer, he had profit and loss (P&L) responsibility, but until beginning St. Louis Chemical, he had limited exposure to company accounting and finance decisions. The company reported small losses during its early years of operation, but performance in recent years has been very good. Sales have grown, new product lines have been added and reported profits have been steadily increasing. The growth has required the acquisition of additional land, equipment, expansion of storage capacity and an increase in work force. Williams has proven to be an expert marketer, and St. Louis Chemical has developed a reputation with its customers of providing quality products and superior service at competitive prices. Despite its business success, St. Louis Chemical is still a "large" small business with Williams making all important decisions. He recognized the need to develop a professional managerial staff, particularly in the area of finance. Recently, he hired Edison Hesselbach as the company's first finance professional and placed him in charge of the company's accounting and finance activities. St. Louis Chemical's board of directors is composed of Williams, his father and the company's attorney. The board's existence satisfies state regulatory requirements for corporations but provides little, if any, input to business operations. Chemical DISTRIBUTION A Chemical distributor is a wholesaler. Operations may vary but a typical distributor purchases Chemicals in large quantities (bulk - barge, rail or truckloads) from a number of manufacturers. They store bulk Chemicals in "tank farms", a number of tanks located in areas surrounded by dikes. The tanks can receive and ship materials from all modes of transportation. Packaged Chemicals are stored in a warehouse. Other distributor activities include blending, repackaging, and shipping in smaller quantities (less than truckload, tote tanks, 5 5 -gallon drums, and other smaller package sizes) to meet the needs of a variety of industrial users. …

Muhammad Ahsan - One of the best experts on this subject based on the ideXlab platform.

  • Comparison of physico-Chemical, advanced oxidation and biological techniques for the textile wastewater treatment
    Alexandria Engineering Journal, 2014
    Co-Authors: Muhammad Saqib Nawaz, Muhammad Ahsan
    Abstract:

    Toxic organic dye removal from the textile wastewater is a serious concern. It is difficult to choose a single or a combination of treatment techniques between various available options; each with certain advantages and drawbacks. Six different techniques were applied on the same textile wastewater to evaluate the most effective in terms of treatment efficiency. The three most important textile wastewater quality parameters of Chemical oxygen demand (COD), total suspended solids (TSS) and color were made the basis of the comparison of different treatment techniques. Other critical parameters such as treatment time, ease of operation and Chemical Cost employed were also considered. No single biological or physico-Chemical treatment technique was found capable of removing up to 80% of the influent COD, TSS and color simultaneously from the textile wastewater. The conventional activated sludge (CAS) treatment followed by effluent polishing with the sand filtration (SF) and activated carbon adsorption columns was proved to be the most promising with COD, TSS and color removal efficiencies of 81.6%, 88.5% and 94.5% respectively. Moreover this combination of techniques enjoys lower Chemical Cost, medium operation time and fewer difficulties in the process control. Hence, the combination is recommended for the treatment of the textile effluents.

Joon Ching Juan - One of the best experts on this subject based on the ideXlab platform.

  • optimization of agro industrial wastewater treatment using unmodified rice starch as a natural coagulant
    Industrial Crops and Products, 2014
    Co-Authors: Ta Yeong Wu, Joon Ching Juan
    Abstract:

    Abstract There have been increasing interests on the use of organic starch derivative coagulants such as cationic starch in coagulation-flocculation process due to environment and health concerns regarding the use of inorganic coagulants. However, studies on the potential utilization of unmodified starch in wastewater treatment remain limited. In this study, treatment performance of unmodified rice starch and alum was tested on agro-industrial wastewater produced from crude palm oil extraction, namely palm oil mill effluent (POME). Response surface methodology (RSM) showed that an addition of unmodified rice starch not only enhanced total suspended solids (TSS) and Chemical oxygen demand (COD) removals; but it also significantly improved the process by reducing both the dosage of alum (−47.95%) and settling time (−58.66%), while shifting the operating pH closer to the natural pH of POME. The treatment enabled TSS and COD removals up to 86.65 and 49.23%, respectively under the optimum conditions of 0.38 g/L alum, 0.28 g/L unmodified rice starch, pH 4.45 and settling time of 5.54 min. An addition of unmodified rice starch to alum also resulted in 33.8% reduction of Chemical Cost as compared to the treatment using alum alone.

David A. Kunz - One of the best experts on this subject based on the ideXlab platform.

  • St. Louis Chemical: Cost of capital.(Instructor's Note)
    Journal of the International Academy of Case Studies, 2011
    Co-Authors: David A. Kunz, Benjamin L. Dow
    Abstract:

    CASE DESCRIPTION The primary subject matter of this case concerns the issues surrounding a firm's weighted average Cost of capital (WACC). Case provides a review of Cost of capital issues. The case requires students to have knowledge of accounting and finance, thus the case has a difficulty level of three (junior level) or higher. The case is designed to be taught in one class session of approximately 1.25 hours and is expected to require 2-3 hours of preparation time from the students. CASE SYNOPSIS The case tells the story of Don Williams, President and primary owner of St. Louis Chemical. By most measures, the performance of St. Louis Chemical has been very good over the last three years, with sales and income increasing each year Business growth has been steady but a recent increase in demand has placed a strain on existing operations. To keep pace with demand, the capacity of the current warehouse and packaging operations need to be increased. The Cost of the facility expansion has been estimated to be $900,000 by St. Louis Chemical's operation manager. Since beginning operations, Williams has been reluctant to borrow funds. He has been content with limited growth, financed with internally generated equity. Recently hired Edison Hesselbach, the company's first finance professional, has recommended borrowing the required funds. Williams indicated he may be willing to consider a change in his long-standing policy against debt, but wants more information regarding using debt in the firm's capital structure. CASE USE The case as written includes discussion questions to aid the student in their analysis of St. Louis Chemical's current situation. The case can be made more difficult by omitting the discussion questions. CASE OVERVIEW As the case opened Don Williams, the President of the St. Louis Chemical, a regional Chemical distributor, headquartered in St. Louis, Missouri, is in need of additional assets and financing to support future growth. To keep pace with demand, the capacity of the current warehouse and packaging operations need to be increased. The Cost of the facility expansion has been estimated to be $900,000 by St. Louis Chemical's operation manager. Williams has also followed a conservative financing policy. Since beginning operations, he has been reluctant to borrow funds, content with limited growth, financed with internally generated equity. The only long-term debt on the company's balance sheet reflects the financing associate with vehicles. If the facility is to be expanded, additional external financing will be necessary. St. Louis Chemical's income statement and balance sheet for the years 2007-2009 are provided in Schedules One and Two, respectively. Hesselbach has recommended borrowing the required funds. Williams indicated he may be willing to consider a change in his long-standing policy against debt, but wants more information regarding the advantages of using debt in the firm's capital structure. Hesselbach, using input from an investment-banking firm, has estimated the company's Cost of equity to be 14%. A St. Louis bank has indicated a long-term bank loan can be arranged to finance expansion at an annual interest rate of 10%. The bank would require either loan to be secured with expansion and other company assets. The loan agreement would also include a number of restrictive covenants, including a limitation of dividends while the loans are outstanding. Only a small amount of long-term debt is included in the firm's current capital structure, the firm's debt ratio at the end of 2009 was 21% and long-term debt was only .28% of total assets (see schedule 2). Hesselbach calculated that if a long-term bank loan was used to obtain the needed $900,000, the firm's debt ratio would increase to 30%. He believes a 30% debt and 70% equity capital mix would be conservative and a starting point for introducing long-term debt into the firm's capital structure. …

  • St. Louis Chemical: Cost of Capital
    Journal of the International Academy of Case Studies, 2011
    Co-Authors: David A. Kunz, Benjamin L. Dow
    Abstract:

    CASE DESCRIPTION The primary subject matter of this case concerns the issues surrounding a firm's weighted average Cost of capital (WACC). Case provides a review of Cost of capital issues. The case requires students to have knowledge of accounting and finance, thus the case has a difficulty level of three (junior level) or higher. The case is designed to be taught in one class session of approximately 1.25 hours and is expected to require 2-3 hours of preparation time from the students. CASE SYNOPSIS The case tells the story of Don Williams, President and primary owner of St. Louis Chemical. By most measures, the performance of St. Louis Chemical has been very good over the last three years, with sales and income increasing each year Business growth has been steady but a recent increase in demand has placed a strain on existing operations. To keep pace with demand, the capacity of the current warehouse and packaging operations need to be increased. The Cost of the facility expansion has been estimated to be $900,000 by St. Louis Chemical's operation manager. Since beginning operations, Williams has been reluctant to borrow funds. He has been content with limited growth, financed with internally generated equity. Recently hired Edison Hesselbach, the company's first finance professional, has recommended borrowing the required funds. Williams indicated he may be willing to consider a change in his long-standing policy against debt, but wants more information regarding using debt in the firm's capital structure. BACKGROUND St. Louis Chemical is a relatively new regional distributor of liquid and dry Chemicals, headquartered in St. Louis, Missouri. The company, founded by Don Williams, has been serving primarily eastern Missouri and western Illinois for four years and has developed a reputation as a reliable supplier of industrial Chemicals. Williams' previous business experience provided him with a solid understanding of the Chemical industry and the distribution process. As a general manager for a Chemical manufacturer, he had profit and loss (P&L) responsibility, but until beginning St. Louis Chemical, he had limited exposure to company accounting and finance decisions. The company reported small losses during its early years of operation, but performance in recent years has been very good. Sales have grown, new product lines have been added and reported profits have been steadily increasing. The growth has required the acquisition of additional land, equipment, expansion of storage capacity and an increase in work force. Williams has proven to be an expert marketer, and St. Louis Chemical has developed a reputation with its customers of providing quality products and superior service at competitive prices. Despite its business success, St. Louis Chemical is still a "large" small business with Williams making all important decisions. He recognized the need to develop a professional managerial staff, particularly in the area of finance. Recently, he hired Edison Hesselbach as the company's first finance professional and placed him in charge of the company's accounting and finance activities. St. Louis Chemical's board of directors is composed of Williams, his father and the company's attorney. The board's existence satisfies state regulatory requirements for corporations but provides little, if any, input to business operations. Chemical DISTRIBUTION A Chemical distributor is a wholesaler. Operations may vary but a typical distributor purchases Chemicals in large quantities (bulk - barge, rail or truckloads) from a number of manufacturers. They store bulk Chemicals in "tank farms", a number of tanks located in areas surrounded by dikes. The tanks can receive and ship materials from all modes of transportation. Packaged Chemicals are stored in a warehouse. Other distributor activities include blending, repackaging, and shipping in smaller quantities (less than truckload, tote tanks, 5 5 -gallon drums, and other smaller package sizes) to meet the needs of a variety of industrial users. …