Upgrading Existing Activated Sludge Treatment Plants with Fine Pore Aeration Systems

1990 ◽  
Vol 22 (7-8) ◽  
pp. 245-251 ◽  
Author(s):  
Michael K. Stenstrom
Keyword(s):  
Activated Sludge ◽  
The United States ◽  
Economic Incentives ◽  
Gas Analysis ◽  
Aeration System ◽  
Analysis Technique ◽  
Aeration Efficiency ◽  
Process Operation ◽  
Cleaning Methods ◽  
Plant Capacity

Over the past ten years aeration systems development in the United States has centered around fine pore diffuser upgrades to existing activated sludge plants. A variety of older aeration systems have been replaced with new diffuser systems which include full floor coverage systems, composed of ceramic or plastic discs, ceramic and plastic tubes, and membrane tubes or discs. This manuscript reports on aeration system upgrades at six different full scale treatment plants. Seven different devices were evaluated using the off-gas analysis technique. Diffuser cleaning methods were also evaluated. Results are presented which show the economic incentives for upgrading and the increased plant capacity which resulted from increased aeration efficiency. It was found that the effects of process operation, such as step feed, F/M, MLSS concentration, mean cell retention time and air flux had a major impact on transfer efficiency. The effects of diffuser fouling and cleaning methods are presented.

scholarly journals Assessment of diffuser pressure loss on WWTPs in Baden-Württemberg

2011 ◽  
Vol 63 (12) ◽  
pp. 3027-3033 ◽  
Author(s):  
J. Krampe
Keyword(s):  
Activated Sludge ◽  
Pressure Loss ◽  
Treatment Process ◽  
Cost Effective ◽  
Current State ◽  
Aeration System ◽  
Fine Bubble ◽  
Cost Effective Treatment ◽  
Cleaning Methods ◽  
Treatment Step

Aeration of activated sludge is a critical treatment step for the operation of activated sludge plants. To achieve a cost effective treatment process, assessing and benchmarking of aeration system performance are important measures. A simple means of gauging the relative condition of a fine bubble diffused aeration system is to evaluate the pressure loss of the diffusers as oxygen transfer tests are rarely applied during the lifetime of an aeration system. This paper shows an assessment of fine bubble diffuser systems in Baden-Württemberg, Germany, based on the results of a questionnaire sent to 941 WWTPs. Apart from the results with regards to the diffuser pressure loss, this paper also presents information on the current state of diffuser technology such as types and materials as well as the diffuser cleaning methods used in Baden-Württemberg. The majority of the WWTPs were equipped with tube diffusers (71%) with 50% of all plants having EPDM membranes installed. Regular mechanical cleaning is the most common cleaning method followed by regular pressure release/air-bumping programs during operations. With regard to the diffuser pressure loss it was found that 50% of the evaluated plants had a diffuser pressure loss that was twice as high as measured for new diffusers.

Case Studies, Trade War Impacts Between USA And China : The Decline Of Cotton Carded Yarn 32/1 Selling Volume To China On Dan Liris Incorporation

2020 ◽  
Vol 11 (1) ◽  
pp. 91-91
Author(s):  
Riza Indah Pramesti A.Md ◽  
Avina Utari A.Md
Keyword(s):  
Mixed Method ◽  
Swot Analysis ◽  
The United States ◽  
External Factors ◽  
Sales Volume ◽  
Employee Welfare ◽  
Analysis Technique ◽  
Trade War ◽  
Conducting Research ◽  
New Strategies

This study aims to describe the prospect of the trend of export sales volume of 32/1 cotton carded yarn in PT Dan Liris. In 2018, the volume of exports of 32/1 cotton carded yarn to China dropped dramatically to zero orders. In addition, research on the decline in the sales volume of exports of 32/1 cotton carded yarn to China aims to find out deeply the flow of the company's external factors, namely trade war which caused a decline in the volume of export sales to China at PT Dan Liris. The method used in this study is a mixed method by providing an overview of the problems that occur in the PT Dan Liris company. The analytical tool in this study is the trend analysis technique by giving an overview of the trend in volume and the prospect of possible future export volumes of yarn products. The results of the analysis of the data obtained are the volume of export sales of PT Dan Liris yarn to China that are upside down or unstable. This study also succeeded in revealing that the existence of external factors in the trade war that occurred between the United States and China was very detrimental to the company in terms of income and continuity of production. Based on the results of the analysis of the data, the authors then conducted a SWOT analysis matrix as the company's alternative. The author suggests 12 new strategies that can be done by PT Dan Liris such as PT Dan Liris can take action by utilizing promotional services either online or offline, conducting research and analyzing the development of buyer countries related to economic issues on a regular basis, as well as the likely impact on the company. A survey of customer satisfaction and attention to employee welfare is also very important to maintain the integrity of the company. Keywords: Sales Volume, Trade War, Company Integrity.

The Hard Sell

2017 ◽  
Author(s):  
Peter Scott
Keyword(s):  
Price Competition ◽  
New Economy ◽  
The United States ◽  
Vacuum Cleaner ◽  
Firm Level ◽  
Direct Sales ◽  
Cost Distribution ◽  
Household Cleaning ◽  
Time Savings ◽  
Cleaning Methods

The vacuum cleaner was an archetypal new economy product of the early twentieth century. It offered both major time savings and qualitative advantages over previous household cleaning methods—the brush, broom, and manual carpet sweeper—and was sold in a novel way (by household demonstration). The direct sales techniques pioneered by vacuum manufacturers in the United States were to have a profound impact on the way vacuums were sold in Britain, and globally. Yet by 1939 their household diffusion was relatively slow compared to refrigerators or washing machines. This chapter explores why the industry evolved a structure based on high prices, high cost distribution methods (door-to-door sales), and a strong emphasis on non-price competition, based on differentiation through features. It also shows how door-to-door selling eventually came to constitute both a key firm-level competitive advantage and a substantial industry-level constraint on product diffusion.

Comparison of the efficiency of large-scale ceramic and membrane aeration systems with the dynamic off-gas method

2002 ◽  
Vol 46 (4-5) ◽  
pp. 317-324 ◽  
Author(s):  
J.A. Libra ◽  
A. Schuchardt ◽  
C. Sahlmann ◽  
J. Handschag ◽  
U. Wiesmann ◽  
...  
Keyword(s):  
Large Scale ◽  
Operating Conditions ◽  
Air Distribution ◽  
Energy Costs ◽  
Dissolved Oxygen Concentration ◽  
Membrane Aeration ◽  
Aeration System ◽  
Oxygen Transfer Efficiency ◽  
Aeration Efficiency ◽  
Period Measurement

The aeration systems of two full-scale activated sludge basins were compared over 2.5 years under the same operating conditions using dynamic off-gas testing. Only the material of the diffuser was different, membrane vs. ceramic tube diffusers. The experimental design took the complexity and dynamics of the system into consideration. The investigation has shown that, although the membrane diffusers have higher initial standard oxygen transfer efficiency (SOTE) and standard aeration efficiency (SAE), these decreased over time, while the SAE of the ceramic diffusers started lower, but increased slightly over the whole period. Measurement of air distribution in the basins along with dissolved oxygen concentration profiles have provided important information on improving process control and reducing energy costs. The results show that dynamic off-gas testing can effectively be used for monitoring the aeration system and to check design assumptions under operating conditions. The information can be used to improve the design of new aeration systems or in retro-fitting existing basins.

Mass transfer impacts in flocculent and granular biomass from SBR systems

2004 ◽  
Vol 50 (10) ◽  
pp. 203-212 ◽  
Author(s):  
D. Gapes ◽  
B.-M. Wilén ◽  
J. Keller
Keyword(s):  
Mass Transfer ◽  
Particle Size ◽  
Oxygen Uptake ◽  
Activated Sludge ◽  
Uptake Rate ◽  
Oxygen Uptake Rate ◽  
Batch Reactor ◽  
Average Particle Size ◽  
Gas Analysis ◽  
Average Particle

An experimental study was conducted to describe mass transfer impacts within nitrifying aggregates sourced from sequencing batch reactor (SBR) activated sludge systems. Flocculent and granular sludge with high nitrification activity was obtained in two laboratory SBR systems, supplied with a synthetic, ammonium-based feed. The flocculent biomass was fractionated using a sieving procedure, in order to obtain biomass fractions with different particle size distributions. The oxygen uptake rate (OUR) response to changes in dissolved oxygen concentration was measured under highly controlled conditions in a titrimetric and off-gas analysis (TOGA) sensor, and the results used to assess mass transfer effects. As the average particle size of the biomass increased, mass transfer limitations were found to increase significantly. Empirically fitted, apparent KS,O2 values were demonstrated to be highly dependent on particle size, and reflect the mass transfer limitations occurring in the aggregates within a given system. Such parameters thus have little to do with the actual biokinetic parameter from which they are derived. The results obtained from the TOGA sensor study were consistent with those obtained from a microelectrode study on the same nitrifying granules. Together, these studies add considerable weight to the conclusion that consideration of external and internal mass transfer limitations is vital to the accurate description of activated sludge treatment processes, particularly those with a high oxygen uptake rate.

scholarly journals A Study of the Environmental Issues Associated with the Dominican RepublicCentral American Free Trade Agreement (DR-CAFTA)

2011 ◽  
Vol 8 (1) ◽  
Author(s):  
Shyamalendu Sarkar
Keyword(s):  
Free Trade ◽  
Capital Investment ◽  
Free Trade Agreement ◽  
Trade Agreement ◽  
The United States ◽  
Economic Incentives ◽  
Central American ◽  
Environmental Objectives ◽  
Environmental Requirements ◽  
The U.S

The Dominican Republic-Central American Free Trade Agreement (DR-CAFTA) with the United States was passed on July 28, 2005. The main goal of DR-CAFTA is to create a free trade zone for economic development. The Agreement is highly controversial with many contentious issues including concern about the environment, which is the focus of this study. The concern is that the environmental objectives are expected to be subservient to trade and other economic incentives which will lead to further deterioration of the environment in countries where the environmental standards are already low. The effects on the U.S. environment are expected to be minimal. However, it is feared that the U.S. manufacturing facilities may relocate to Central American countries to take advantage of low wages and low environmental requirements, which may result in loss of jobs and capital investment in the U.S. However, overall DR-CAFTA is expected to be beneficial in many ways, including an increase in trade and economic growth in all participating countries.

scholarly journals Sanctions in U.S. - Russia Relations

2020 ◽  
Vol 20 (3) ◽  
pp. 504-520
Author(s):  
Charles E. Ziegler
Keyword(s):  
Global Economy ◽  
The United States ◽  
Economic Incentives ◽  
Primary Sources ◽  
Maximum Pressure ◽  
Significant Deterioration ◽  
Executive Orders ◽  
Rogue States ◽  
Leading Position ◽  
The U.S

Given America’s leading position in the global economy, the U.S. government has frequently leveraged that power to punish “rogue states”, discourage nuclear proliferation, promote democratization, and create pressure for regime change. Washington relied on economic incentives in relations with Russia after 1991, but since 2012 the United States has utilized a broad range of economic sanctions against Russian side, leading to a significant deterioration in what was already a troubled relationship. In contrast to earlier comprehensive sanctions like those imposed on Iraq and Haiti, the U.S. is now crafting “smart” or targeted sanctions designed to exert maximum pressure on selected Russian elites and firms. Rather than evaluating the effectiveness of these measures on changing Russian behavior, the author explores the neglected domestic dimension of the U.S. sanctions process to improve understanding of U.S. foreign policy. This article draws on primary sources in the form of Congressional legislation, executive orders, and official statements to analyze U.S. sanctions imposed on Russia, and develops three brief case studies - the Magnitsky Act, post-Ukraine sanctions, and the Countering America’s Adversaries Through Sanctions Act - to explicate the main issues and actors driving U.S. sanctions. The author argues that domestic factors, including Congressional pressures and interest group activity, are critical to understanding U.S. sanctions regimes. While President Donald Trump has frequently resisted congressionally imposed sanctions, expectations for a more conciliatory approach towards Russia under the Trump administration have not materialized.

THE BRANDCASTING ON THE EXAMPLE OF ADVERTORIALS

2021 ◽  
Author(s):  
Aneta Duda
Keyword(s):  
United States ◽  
Content Analysis ◽  
United States Of America ◽  
The United States ◽  
Brand Positioning ◽  
Editorial Content ◽  
Organized Interests ◽  
Analysis Technique ◽  
The Media ◽  
Degree Of Similarity

"This article discusses the concept of brandcasting in the particular case of a controversial advertorial (ADL) - paid messages in the media sponsored by organized interests to create and sustain a favorable environment to pursue their respective goals. An advertorial is an advertisement masquerading as a journalistic article, blurring the dividing line between editorial content and advertorials. Based on the content analysis technique of 284 advertorials of Newsweek, Polityka and Time, the most widely circulated and read weekly newsmagazine in Poland and the United States of America, the author documents the placement of ADL: proportions of commercial and non-commercial content, detailed typologies, brand positioning, sponsor disclosures, the degree of similarity with journalistic texts and corporate and non-corporate interests. The newspaper advertorial borrows, or just steals editorial credibility from the newspaper and pollutes reliable information. There, of course, might be a place for such kind of advertisements, but they should be more thoroughly distinguished form editorial content than is currently the case. As shown in the article, media do not place sponsor disclosures prominently."

The Effects of State and Local Economic Incentives on Business Start-Ups in the United States: County-Level Evidence

2020 ◽  
Vol 34 (2) ◽  
pp. 171-187
Author(s):  
Mark Partridge ◽  
Sydney Schreiner ◽  
Alexandra Tsvetkova ◽  
Carlianne Elizabeth Patrick
Keyword(s):  
Local Economic Development ◽  
Negative Relationship ◽  
The United States ◽  
Economic Incentives ◽  
Policy Makers ◽  
Start Up ◽  
Labor Market Flexibility ◽  
State And Local ◽  
Start Ups

Even as economic incentives are increasingly used by policy makers to spur state and local economic development, their use is controversial among the public and academics. The authors examine whether state and local incentives lead to higher rates of business start-ups in metropolitan counties. Existing research indicates that start-ups are important for supporting (net) job creation, long-term growth, innovation, and development. The authors find that incentives have a statistically significant, negative relationship with start-up rates in total and for some industries including export-based and others that often receive incentives. The findings support critics who contend that incentives crowd out other economic activity, potentially reducing long-term growth. The authors also find that greater intersectoral job flows are positively linked to total start-ups, consistent with claims of those who advocate for policies that enhance labor market flexibility through reducing barriers to job mobility.

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