On the Problem of “Two-Phase” Activated Sludge

1991 ◽  
Vol 24 (7) ◽  
pp. 59-64 ◽  
Author(s):  
R. W. Szetela
Keyword(s):  
Activated Sludge ◽  
Single Phase ◽  
Phase System ◽  
Two Phase ◽  
Wastewater Treatment Process ◽  
Sludge Stabilization ◽  
Technological Advantage ◽  
In Series ◽  
State Models ◽  
Activated Sludge Systems

Steady-state models are presented to describe the wastewater treatment process in two activated sludge systems. One of these makes use of a single complete-mix reactor; the other one involves two complete-mix reactors arranged in series. The in-series system is equivalent to what is known as the “two-phase” activated sludge, a concept which is now being launched throughout Poland in conjunction with the PROMLECZ technology under implementation. Analysis of the mathematical models has revealed the following: (1) treatment efficiency, excess sludge production, energy consumption, and the degree of sludge stabilization are identical in the two systems; (2) there exists a technological equivalence of “two-phase” sludge with “single-phase” sludge; (3) the “two-phase” system has no technological advantage over the “single-phase” system.

The Temperature-Phased Anaerobic Biofilter Process

1994 ◽  
Vol 29 (9) ◽  
pp. 213-223 ◽  
Author(s):  
Sandra K. Kaiser ◽  
Richard R. Dague
Keyword(s):  
System Performance ◽  
Anaerobic Treatment ◽  
Size Ratio ◽  
High Rate ◽  
Phase System ◽  
Optimum Size ◽  
Treatment Technology ◽  
Two Phase ◽  
In Series ◽  
Two Temperature

The “temperature-phased anaerobic biofilter” or TPAB process (U.S. Patent pending), is a new high-rate anaerobic treatment system that includes a thermophilic (56°C) biofilter connected in series with a mesophilic (35°C) biofilter providing for two-temperature, two-phase treatment. Three TPAB systems of different thermophilic:mesophilic reactor size ratios were operated at system HRTs of 24 hrs, 36 hrs, and 48 hrs to characterize performance and to determine if an optimum size ratio exists between the thermophilic and mesophilic phases. The three TPAB systems achieved SCOD reductions in excess of 97% and TCOD reductions in excess of 90% for a synthetic milk substrate over a range of system COD loadings from 2 g COD/L/day to 16 g COD/L/day. There was little difference in performance between the three TPAB systems based on COD reduction and methane production. The 1:7 ratio of thermophilic:mesophilic phase TPAB system performed as well as the 1:3 and 1:1 size ratio TPAB systems. In applications of the process, a relatively small thermophilic first-phase can be used without sacrificing overall two-phase system performance. The TPAB process is a promising new anaerobic treatment technology with the ability to achieve higher efficiencies of organic removals than is generally possible for single-stage anaerobic filter systems operated at equivalent HRTs and organic loadings.

scholarly journals Multi-machine transient stability by using static synchronous series compensator

2020 ◽  
Vol 11 (3) ◽  
pp. 1249
Author(s):  
Nur Ashida Salim ◽  
Nur Diyana Shahirah Mohd Zain ◽  
Hasmaini Mohamad ◽  
Zuhaila Mat Yasin ◽  
Nur Fadilah Ab Aziz
Keyword(s):  
Power System ◽  
Transient Stability ◽  
Single Phase ◽  
Power Transmission ◽  
System Stability ◽  
Phase System ◽  
Proportional Integral ◽  
Before And After ◽  
In Series ◽  
Static Synchronous Series Compensator

<span lang="EN-US">Transient stability in power system is vital to be addressed due to large disturbances that could damage the system such as load changes and voltage increases. This paper presents a multi-machine transient stability using the Static Synchronous Series Compensator (SSSC). SSSC is a device that is connected in series with the power transmission line and produces controllable voltage which contribute to a better performance in the power system stability. As a result, this research has observed a comparison of the synchronization of a three-phase system during single-phase faults before and after installing the SSSC device. In addition, this research investigates the ability of three different types of controllers i.e. Proportional Integral (PI), Proportional Integral Derivation (PID), and Generic controllers to be added to the SSSC improve the transient stability as it cannot operate by itself. This is because the improvement is too small and not able to achieve the desired output. The task presented is to improve the synchronization of the system and time taken for the voltage to stabilize due to the fault. The simulation result shows that the SSSC with an additional controller can improve the stability of a multi-machine power system in a single phase fault.</span>

Prediction of Two-Phase Pressure Drop and Density Distribution From Mixing Length Theory

1963 ◽  
Vol 85 (2) ◽  
pp. 137-150 ◽  
Author(s):  
S. Levy
Keyword(s):  
Single Phase ◽  
Continuous Medium ◽  
Phase System ◽  
Mixing Length ◽  
Test Results ◽  
Two Phase ◽  
Pressure Drops ◽  
Mixing Length Theory ◽  
Phase Pressure ◽  
Good Agreement

Single-phase turbulent mixing length methods are used to predict two-phase flow. Two-phase density and velocity distributions and two-phase pressure drops are derived by treating the two-phase system as a continuous medium where the turbulent exchanges of momentum and density are equal. Good agreement is obtained between test results and analytical predictions.

Experimental Investigation of Evacuated Tube Solar Collector with Annular Heat Exchanger

2014 ◽  
Vol 592-594 ◽  
pp. 2355-2359
Author(s):  
Narasimhe Gowda ◽  
B. Putta Bore Gowda ◽  
R. Chandrashekar ◽  
G. Ugrasen ◽  
R. Keshavamurthy
Keyword(s):  
Closed System ◽  
Single Phase ◽  
Working Fluid ◽  
Maintenance Cost ◽  
Phase System ◽  
Two Phase ◽  
Solar Water ◽  
Water Heaters ◽  
Solar Water Heaters ◽  
Evacuated Tube

Now-a-days evacuated tubes solar water heaters are increasingly use in South India because of good thermal efficiency and high water temperature could be achievable as compared to flat plate solar collectors. Low manufacturing and maintenance cost also attract people to go for evacuated tube solar water heaters. This paper reports experimental results of two types of evacuated tube solar water heaters. To evaluate the performance of evacuated tube solar water heater, single-phase forced system and two-phase closed forced systems were considered. In two-phase closed system sunflower oil was used as working fluid to heat water. Throughout the study two-phase closed system shows better performance compared to single-phase open collector system and their efficiency almost 10 to 12% higher. But, because of high initial cost of two-phase system, the pay back periods of both collector systems is almost same. In two phased closed system higher temperature of water could be achieved, which is very useful to operate advanced system.

scholarly journals Production strategy influence on the economic viability of a family fish farm in Pará state, Amazon, Brazil

2021 ◽  
Vol 9 (1) ◽  
pp. 540-549
Author(s):  
Marcos Ferreira Brabo ◽  
Gerfeson Almeida da Silva ◽  
Daniel Abreu Vasconcelos Campelo ◽  
Galileu Crovatto Veras ◽  
Andréia Santana Bezerra ◽  
...  
Keyword(s):  
Single Phase ◽  
Net Present Value ◽  
Cost Benefit ◽  
Phase System ◽  
Operational Cost ◽  
Internal Rate Of Return ◽  
Two Phase ◽  
Cost Benefit Ratio ◽  
The Cost ◽  
Capital Return

The objective of this study was to analyze the influence of the adoption of single-phase and two-phase system on the economic feasibility of tambaqui (Colossoma macropomum) family production in the Tracuateua municipality, Pará state. The operational cost methodology and economic efficiency indicators were adopted to compare these rearing systems. The annual production was 4,200 kg and 5,826 kg. The operational costs were R$ 26,169.00 and R$ 34,365.00, the total operational cost was R$ 27,505 and R$ 35,701.00, and the total operational cost per kg was R$ 6.55 and R$ 6.13 for single-phase and two-phase systems, respectively. Regarding the indicators, the net present value was R$ 24,180.70, the internal rate of return was 24%, the cost-benefit ratio was 1.19, and the capital return period was four years in the single-phase system. In the two-phase period, the net present value was R$ 48,582.06, the internal rate of return was 29%, the cost-benefit ratio was 1.25, and the capital return period was 3.6 years. Despite the demand for greater investment, the two-phase system proved to be more profitable than the single-phase system, promoting even a reduction in unit production cost.

Treatment of Oily Cafeteria Wastewater by Single-Phase and Two-Phase Anaerobic Filter

1990 ◽  
Vol 22 (3-4) ◽  
pp. 299-306 ◽  
Author(s):  
Keisuke Hanaki ◽  
Tomonori Matsuo ◽  
Katsuo Kumazaki
Keyword(s):  
Single Phase ◽  
Material Balance ◽  
Phase System ◽  
Two Phase ◽  
Term Operation ◽  
Effluent Quality ◽  
Anaerobic Filter ◽  
Phase Systems ◽  
Better Than

Cafeteria wastewater containing about 30% of lipid on COD basis was treated at 20°C by laboratory-scale anaerobic filter in single-phase system and two-phase systems. Stable COD removal (about 80%) was achieved in spite of large fluctuation in influent COD concentration (normal range of 1,300 - 2,500 mg−l) both in the single-phase system (hydraulic retention time (HRT) longer than 1.3 d) and in the two-phase system (HRT longer than 3.3 d). The single-phase system gave better effluent quality than the two-phase system because the former entrapped suspended solids better than the latter. However, material balance revealed that methane conversion from removed COD was higher in the two-phase system than the single-phase system. The single-phase system perhaps removed lipids by entrapment with filter media without biodegradation, and this might cause clogging problems in long-term operation. The two-phase system is recommended since it degrades lipids better than the single-phase system.

High Cycle Fatigue Behaviour of Cu/Sn Intermetallic Compounds Prepared by Transient Liquid Phase Bonding Process

2021 ◽  
Vol 1016 ◽  
pp. 268-273
Author(s):  
Agnieszka Betzwar Kotas ◽  
Golta Khatibi ◽  
Farzad Khodabakhshi ◽  
Andreas Steiger-Thrisfeld
Keyword(s):  
Mechanical Properties ◽  
Liquid Phase ◽  
Single Phase ◽  
Transient Liquid Phase ◽  
Physical And Mechanical Properties ◽  
Test System ◽  
Bending Test ◽  
Fatigue Properties ◽  
Phase System ◽  
Two Phase

Transient liquid phase (TLP) bonds using Cu-Sn system have been suggested as high strength and temperature resistant joints for power electronics applications. While the physical and mechanical properties of these joints has been investigated to some extent, studies on fatigue properties and long term reliability of TLP joints are scarce. In this work TLP bonding was performed to produce thin Cu-Sn intermetallic joints by using Cu and 97Sn3Cu solder alloy as interlayer. Different processing conditions resulted in three types of thin joints consisting of three phases (Cu3Sn/Cu6Sn5/solder remnants), two phases (Cu3Sn/Cu6Sn5) and a single phase (Cu3Sn) with an overall thickness of ≤ 20 μm. The shear strength of the TLP joint containing one or two high melting point IMC layers showed a significant temperature resistance up to 200°C. Fatigue studies of TLP joints were conducted by using a 3-point-cyclic bending test system operating at 20 kHz. The highest fatigue resistance was obtained for the single-phase Cu3Sn joints with superior shear and flexural resistance. The two phase joints (Cu3Sn/Cu6Sn5) showed a slightly lower lifetime than the three phase system containing IMCs and residual solder. Fracture surfaces analysis in correlation with static and cyclic mechanical properties, provided insight into the failure mechanism of the Cu-Sn TLP joints.

Modelling Simulation and Control of an Existing Activated Sludge Wastewater Treatment Process

1976 ◽  
Vol 11 (1) ◽  
pp. 108-121
Author(s):  
N. Thérien ◽  
P. Harrington
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Flow Rate ◽  
Treatment Plant ◽  
Organic Substrate ◽  
Activated Sludge Process ◽  
Two Phase ◽  
Wastewater Treatment Process ◽  
Wastewater Stream ◽  
And Control

Abstract The dynamic response of the activated sludge process in the wastewater treatment plant of the Centre Hospitalier Universitaire de Sherbrooke was analysed with respect to large disturbances in both the flow rate and the quality of wastewater entering the plant. A mass balance conducted for the organic substrate and biomass entering and leaving the process led to a model consisting of two separate differential equations in terms of BOD and VSS with a two-phase bio-kinetic relationship for the reaction term. Predictions of the model for BOD and VSS variations in time were compared to experimental observations at the plant. A model using mean daily values for VSS and expressed in terms of BOD for the stream flowing out the clarifier unit in response to flow rate and BOD cyclic fluctuations of the entering wastewater stream to the process was found apt at describing the time at which BOD peaks in the process effluent occurred as well as predicting the magnitude of these peaks. The dynamic behaviour of the activated sludge process has been simulated for periods of one to several days using this model. Its use in predicting appropriate control action in time in order to improve the treatment efficiency is also indicated.

Prevention of Lipid Inhibition in Anaerobic Processes by Introducing a Two-Phase System

1991 ◽  
Vol 23 (7-9) ◽  
pp. 1189-1200 ◽  
Author(s):  
Toshiya Komatsu ◽  
Keisuke Hanaki ◽  
Tomonori Matsuo
Keyword(s):  
Single Phase ◽  
Inhibitory Effect ◽  
Phase System ◽  
Long Chain Fatty Acids ◽  
Beta Oxidation ◽  
Two Phase ◽  
Anaerobic Processes ◽  
Ph Values ◽  
Acidogenic Reactor ◽  
Oxidation Degradation

The inhibitory effect of lipids and prevention of this inhibition in a two-phase anaerobic process were examined using laboratory-scale reactors and batch experiments. Lipids were satisfactorily degraded in a two-phase anaerobic filter while in a single-phase system, inhibition resulted in poor lipid degradation. Unsaturated long-chain fatty acids (LFAs) had a greater inhibitory effect than saturated LFAs. Methane production as well as beta-oxidation (degradation of saturated LFAs) were inhibited by unsaturated LFAs. The saturation of unsaturated LFAs was not inhibited, and palmitate (C16:0) was accumulated in the degradation of oleate (C18:l) or linoleate (C18:2). Greater inhibition was observed at low pH values. Continuous operation of a suspended-growth acidogenic reactor showed that hydraulic retention times (HRTs) of no less than 8 hours were necessary to mitigate the inhibition in a two-phase process. The fact that saturation of oleate occurred at HRTs no less than 8 hours suggests that the saturation of unsaturated LFAs in an acidogenic reactor is essential in the prevention of lipid inhibition in two-phase anaerobic processes.

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