The design and performance of a nitrifying vertical-flow reed bed treatment system

1997 ◽  
Vol 35 (5) ◽  
pp. 215-221 ◽  
Author(s):  
Paul Cooper ◽  
Mark Smith ◽  
Henrietta Maynard

The paper describes the design, construction and the monitoring of a vertical-flow Reed Bed Treatment System (RBTS) which achieves tertiary nitrification of the effluent from a biological filter, treating the sewage flow from a population of about 200 people. It treats the flows from toilets, kitchen laboratories and a saline wastewater. The RBTS system takes effluent from an old biological filter and produces a nitrified effluent from a two-stage intermittently-dosed system. The paper shows the long-term performance of the system over a 4 year period and also describes experiments to assess the nitrification performance using a step-feed of ammonium nitrate solution. The system shows a removal of 8-13 g NH4-N/m3 of bed day. The design basis is shown and the operational features described.

2020 ◽  
Vol 57 (8) ◽  
pp. 1130-1152 ◽  
Author(s):  
R.S. McWatters ◽  
R.K. Rowe ◽  
V. Di Battista ◽  
B. Sfiligoj ◽  
D. Wilkins ◽  
...  

An Antarctic biopile using a composite liner (high-density polyethylene geomembrane (GMB) over a geosynthetic clay liner (GCL)) was constructed on a coarse granular subgrade to contain hydrocarbon-contaminated soil and leachate. The soil was remediated after 4 years and the biopile was decommissioned. The liner was exhumed to assess the properties and performance of the GMB and GCL. There was no significant change in the GMB index properties. Although cobbles and coarse gravel of the subgrade had left indentations in the GMB, implying tensile strains that could impact long-term performance, there were no holes. There was significant variability in the hydration of the GCL (from 10% to 220%) and in the underlying subgrade soil water content (from 5% to 30%). This reflects the complexity of the subgrade and groundwater flow in the Antarctic environment. The exhumed GCL specimens had low hydraulic conductivity (1 × 10−11 to 7 × 10−11 m/s) at 13 kPa. Soil samples from below the composite liner showed no detectable hydrocarbons and confirmed no migration through the barrier. It is concluded that the composite barrier contained the leachate and biopile soil over the 4 years in service in the extreme Antarctic conditions.


Author(s):  
Wim Cool ◽  
Elise Vermariën ◽  
William Wacquier ◽  
Janez Perko

ONDRAF/NIRAS, the Belgian Agency for Radioactive Waste and Enriched Fissile Materials, and its partners have developed long-term safety and performance analyses in the framework of the license application for a surface disposal facility for low level radioactive waste (category A waste) at Dessel, Belgium. This paper focusses on the methodology of the safety assessments and on key results from the application of this methodology. An overview is given (1) of the performance analyses for the containment safety function of the disposal system and (2) of the radiological impact analyses confirming that radiological impacts are below applicable reference values and constraints and leading to radiological criteria for the waste and the facility. In this discussion, multiple indicators for performance and safety are used to illustrate the multi-faceted nature of long-term performance and safety of the surface disposal. This contributes to the multiple lines of reasoning for confidence building that a positive decision to proceed to the next stage of construction is justified.


2014 ◽  
Vol 5 (2) ◽  
Author(s):  
Mimin Nur Aisyah

Compensation system has been broadly discussed because of its significant role in enhancing productivity dan performance. It able to motivate a goal directed behavior. Compensation system is expected to provide organizational goal congruence. There are several norms that will lead to different reward distribution. In determining what compensation system that should be taken, organization should consider these dimensions: (1) short term vs long term, (2) cash vs equity, and (3) monetary vs non monetary. Strategy and performance play important role in organizational compensation system. Empirical evidences had support the relation between company’s strategy and its incentive system. Strategic orientation has significant effect on incentive system. To intervene the gap between what is actually needed from compensation system and its practices, the design of reward system should be improved through: (1) give reward to managers only if they perform better than competitors, (2) determine the contribution of each business unit to company stock price, and (3) involve the contribution of front line manager and employees in achieving higher shareholder values. Theory has supports the effectiveness of compensation system, but some evidences showed the contrary. The failness of incentive plans to motivate long term performance should drive the organization to improve the design and implementation of the existed system or to create a new and more effective incentive system.


2018 ◽  
Vol 56 (9) ◽  
pp. 1956-1968 ◽  
Author(s):  
Gun Jea Yu ◽  
Joonkyum Lee

Purpose The purpose of this paper is to investigate the contrasting moderating effect of a firm’s exploration on the relationship between the two types of long-term incentives (stock options/stock ownership) for the chief executive officers and a firm’s long-term performance. Even though the two types of incentives are designed to improve long-term performance, the degrees of impact on long-term performance differ. Based on behavioral agency theory, this study theoretically and empirically examines the role of a firm’s exploration on the above relationship. Design/methodology/approach This study used three archival sources to obtain data on stock options, stock ownership, patents and exploration, financial measures, and others. Based on a sample of 1,963 firms in various industries from 1995 to 2006, this study tested the moderating effect of a firm’s exploration on the relationship between stock options/ownership and a firm’s performance. Findings This study reveals the contrasting moderating effect of a firm’s exploration on the relationship between stock options/ownership and a firm’s long-term performance: a positive moderating effect on the relationship between stock options and performance and a negative moderating effect on the relationship between stock ownership and performance. In addition, empirical evidence was added on the inverted U-shaped relationship between stock ownership and a firm’s long-term performance. Originality/value There is little research on a firm’s internal characteristics that strengthen or weaken the effects of stock options and stock ownership on firm performance. This study demonstrates the differential moderating effects of exploration on the relationship between stock options/stock ownership and long-term performance. Such effects of exploration come from the different risk features of stock options and stock ownership. The key implication is that stock options could be more effective than stock ownership to enhance a firm’s long-term performance when a firm has a strong exploration orientation.


2016 ◽  
Vol 11 (2) ◽  
pp. 57-74 ◽  
Author(s):  
Aiman Albatayneh ◽  
Dariusz Alterman ◽  
Adrian W. Page ◽  
Behdad Moghtaderi

The determination of internal building air temperature has an impact on the design and performance of a building in measuring thermal comfort and heating and cooling loads. There is software to assist with measuring internal building air temperature such as Autodesk CFD simulation. However, the use of Autodesk CFD simulation for the analysis appears to have an issue with simulations extending over a long term (i.e. months or years) as the internal air temperature in a building keeps rising with time. This paper addresses the challenges encountered using CFD simulation in the modelling of a building for long term performance. A new method to overcome the issue of the progressive rising of internal air temperature using two external air boundaries, one for the external volume (sky boundary) and the other surrounding the building, is suggested in the paper.


2011 ◽  
Vol 63 (11) ◽  
pp. 2719-2724 ◽  
Author(s):  
Junmei Wu ◽  
Feng He ◽  
Dong Xu ◽  
Rong Wang ◽  
Xiangling Zhang ◽  
...  

This research aimed to investigate the phosphorus (P) removal of a series of laboratory-scale unvegetated vertical-flow constructed wetland systems using anthracite, steel slag and related blends as substrate in treatment of low concentration domestic sewage. The long-term performance of P removal was firstly studied by using single substrate of anthracite or steel slag, and three systems applying various combined substrates were investigated when the average P loading rate varied between 0.9 and 1.5 g TP/m2·d. The results demonstrated that both anthracite and steel slag systems were highly effective in removing total P (TP, 77.17 ± 23.34% and 90.26 ± 4.48%) and soluble reactive P (SRP, 92.14 ± 12.56% and 96.20 ± 2.58%). The system filled with anthracite, vermiculite and steel slag from the top down removed 82.45 ± 9.52% and 87.83 ± 8.58% of TP and SRP, respectively. However, other combined substrate systems showed comparative low and fluctuant P removal. The effluent pH was maintained at 7–9, which met environmental requirements of China. Therefore, anthracite provides a long-term high efficiency of P removal and may be a promising substrate from the standpoint of the effluent pH, and the arrangement of combined substrate has a prominent effect on P removal.


2016 ◽  
Vol 29 (3) ◽  
pp. 327-346 ◽  
Author(s):  
Julio Diéguez-Soto ◽  
Montserrat Manzaneque ◽  
Alfonso A. Rojo-Ramírez

The aim of this research is to study the moderating role of family management in the relationships between the intensity of research and development and the occurrence of continuous technological innovation and between the existence of technological innovation outcomes and long-term firm performance. The results show that family management reduces efficiency in the conversion of research and development expenses into technological innovation outcomes over time. Our findings also suggest that the influence of family management significantly contributes to improving the effect of the achievement of technological innovation on long-term performance.


Nutrients ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 665 ◽  
Author(s):  
Bryan Holtzman ◽  
Kathryn Ackerman

Appropriate energy intake is important for the health and performance of athletes. When an athlete’s energy intake is not concordant with energy expenditure, short- and long-term performance can be compromised and negative health effects may arise. The energy intake patterns of athletes are subject to numerous effectors, including exercise response, time, and availability of food. To assess different determinants of energy intake in athletes, we reviewed recent literature regarding the response of appetite-regulating hormones to exercise, appetite perceptions following exercise, chronic exercise-induced adaptations regarding appetite, and social factors regarding energy intake. Additionally, we discussed consequences of aberrant energy intake. The purpose of this review is to clarify understanding about energy intake in athletes and provide insights into methods toward maintaining proper energy intake.


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