Decentralised treatment of concentrated sewage at low temperature in a two-step anaerobic system: two upflow-hybrid septic tanks

2003 ◽  
Vol 48 (6) ◽  
pp. 219-226 ◽  
Author(s):  
T.A. Elmitwalli ◽  
S. Sayed ◽  
L. Groendijk ◽  
J. van Lier ◽  
G. Zeeman ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Low Temperature ◽  
Domestic Sewage ◽  
Septic Tank ◽  
Septic Tanks ◽  
Black Water ◽  
Short Run ◽  
One Step ◽  
The Mathematical Model ◽  
Anaerobic System

The decentralised treatment of concentrated sewage (about 3,600 mgCOD/l) at low temperature was investigated in a two-step anaerobic system: two-anaerobic hybrid (AH) septic tanks (each 0.575 m3). The two reactors were placed in a temperature controlled-room and the HRT was 2.5 days for each reactor. The system was fed with concentrated domestic sewage, mainly black water from about 40 toilets flushed with only 4 litre of water and a limited amount of grey water. The system showed high removal efficiency for the different COD fractions. Mean removal efficiencies in the two-step AH-septic tank at 5 days HRT and 13°C were 94, 98, 74 and 78% for total COD, suspended COD, colloidal COD and dissolved COD respectively. The results of short run experiments indicated that the presence of reticulated polyurethane foam (RPF) media in the AH-septic tank improved the removal of suspended COD by 22%. The first AH-septic tank was full of sludge after 4 months of operation due to the high removal of particulate COD and the limited hydrolysis at low temperature conditions. Therefore, a simple mathematical model was developed based on ADM1 (the IWA model in 2002). Based on the experimental results and the mathematical model, only a one-step AH septic tank is required. An HRT of 5.5-7.5 days is needed for that one-step AH septic tank to treat concentrated sewage at a low temperature of 13°C. Such a system can provide a total COD removal as high as 87% and will be full of sludge after a period of more than a year.

Anaerobic treatment of domestic sewage in modified septic tanks at low temperature

2014 ◽  
Vol 35 (17) ◽  
pp. 2123-2131 ◽  
Author(s):  
Zhiqiang Chen ◽  
Qinxue Wen ◽  
Huabin Guan ◽  
Rune Bakke ◽  
Nanqi Ren
Keyword(s):  
Low Temperature ◽  
Anaerobic Treatment ◽  
Domestic Sewage ◽  
Septic Tanks

Study of the Mathematical Model for Online Predicting Mix Mooney Viscosity on the Rubber Open Mill

2013 ◽  
Vol 561 ◽  
pp. 54-58
Author(s):  
Xian Kui Zeng ◽  
Chang He Yang ◽  
Ze Shuai Song ◽  
Shu Hong Zhao
Keyword(s):  
Mathematical Model ◽  
Low Temperature ◽  
The Self ◽  
Experimental Results ◽  
Mooney Viscosity ◽  
The Mathematical Model ◽  
Predictive Effect

According to studying the mechanism of open mill mixing in low temperature and its intelligent mixing theory, based on the analysis of the experimental results getting from the self-developed XK-160E type open mill, we established a mathematical model for predicting the mix Mooney viscosity. The inspection and verification of mathematical model results showed that the predicted Mooney viscosity was very close to the practical value indicating a good predictive effect．

Study on the Electrolysis Expansion of Carbon Cathode in [K3AlF6/Na3AlF6]-AlF3-Al2O3 Low Temperature Melts

2013 ◽  
Vol 749 ◽  
pp. 633-642
Author(s):  
Zhao Fang ◽  
Peng Fei Xu ◽  
Jian Xu ◽  
Lin Bo Li ◽  
Jun Zhu
Keyword(s):  
Mathematical Model ◽  
Low Temperature ◽  
Alkali Metal ◽  
Test Results ◽  
Carbon Cathode ◽  
The Mathematical Model ◽  
Good Agreement

Electrolysis expansion of carbon cathodes due to alkali metal penetration in [K3AlF6/Na3AlF6]-AlF3-Al2O3 melts was tested. Effect of ampere density and superheating temperature on the electrolysis expansion was studied. A mathematical model was got to numerically describe electrolysis expansion performance of carbon cathode. The results indicated that K and Na penetrate into carbon cathode from outside to inside. Ampere density and superheating temperature had a great effect on the electrolysis expansion of carbon cathode. With the superheating temperature increasing from 10 to 50, electrolysis expansion increased from 1.41% to 2.10% gradually. With the ampere density increasing, the increase trend of electrolysis expansion was not linear. When ampere density was lower than 0.4A / cm2 and greater than 0.7A / cm2, cathode electrolysis expansion obviously increased with the increase of ampere density. Meanwhile, cathode electrolysis expansion tended to be constant as the ampere density changed at the range of 0.4A / cm2 to 0.7A / cm2.The results of the mathematical model in this study had a good agreement with the test results. This model would be helpful to accurately describe the anti-penetration performance of K and Na on the carbon cathode.

scholarly journals ASSESSMENT OF USAGE CONDITIONS OF SEPTIC TANKS IN HA NOI AND HAI PHONG

2020 ◽  
Vol 58 (3A) ◽  
pp. 133
Author(s):  
Huong Thi Thu Hoang ◽  
Tuyet Thi Anh Nguyen ◽  
Hung Quang Dinh
Keyword(s):  
Total Coliform ◽  
Poor Quality ◽  
Septic Tank ◽  
Water Volume ◽  
Wastewater Sample ◽  
Septic Tanks ◽  
Black Water ◽  
Wastewater Quality ◽  
Interview Survey ◽  
Survey Results

The study had been conducted in 2017-2018 to generate usage conditions of septic tanks in Ha Noi and Hai Phong through (1) collecting information on usage condition of septic tanks by interview survey; (2) obtaining analytical results of wastewater inflowing to and out flowing from the septic tanks selected by interview survey results. The number of target interview surveys was 200 including both type of the septic tanks treating (i) black water only, and (ii) black and grey water. Among the septic tanks surveyed, 20 septic tanks were selected for collecting discharged wastewater sample and analysing discharged wastewater quality. The analysed parameters included water temperature, pH, BOD5, COD, TSS, Total Phosphorous (TP), Total Nitrogen (TN), NH4-N, and total coliform. Poor quality of wastewater discharged from septic tanks proved the inefficiency of septic tanks in treating black water from the households. As the results, desludging frequency of the septic tanks were recommended through the relationship between desludging interval and effluent water quality from septic tank. And the recommended volume of water-saving toilets was determined through the distributions of “water volume per flush in toilet”, “water consumption”, “estimated volume of septic tanks” and “desludging frequency” in Ha Noi and Hai Phong.

Re-engineering Domestic Septic Tanks into Biogas Tanks

2018 ◽  
Vol 2 (2) ◽  
pp. 54-62
Author(s):  
Mawufemo Modjinou
Keyword(s):  
Anaerobic Digestion ◽  
Environmental Protection Agency ◽  
Suspended Solids ◽  
Sea Water ◽  
Operating Cost ◽  
Oxygen Demand ◽  
Domestic Sewage ◽  
Green Technology ◽  
Septic Tank ◽  
Septic Tanks

This study is to design a novel septic tank, named Anaerobic Upflow Domestic Septic Tank (AUDST) to recover biogas asenergy and treat domestic sewage. The green technology proposes alternate options to existing Domestic Septic Tanks (DST),encourages anaerobically pre-treatment to reduce bacteria, pollutants, Total Suspended Solids (TSS), Chemical oxygen demand(COD) and Biological oxygen demand (BOD) before the effluent is discharged or is removed by cesspit trucks. Studies haveshown that DST in homes partially treat or just store sewage. Again, these DST have to be emptied from time to time becauseit lack features that will sustain anaerobic activity and usually the sludge is disposed of directly into the sea, water bodies andeven into open places such as “Lavender Hills” without any treatment or disinfection. These practices cause severe public healthand environmental problems. To tackle the challenge at household level, DST are redesigned to treat domestic sewage with lessmanagement, low operating cost, low secondary discharge of pollutants. The proposed new design concept is operated throughthree (3) units: such as desilting, anaerobic digestion and facultative filtration units. The anaerobic digestion stage is made upof baffle and anaerobic filter for accommodating sludge and providing a more intimate contact between anaerobic biomass andsewage which improves treatment performance. The anaerobic unit is fitted with locally woven baskets prefilled with packingmaterials. The aim is to strengthen the biological treatment process at this stage. The Facultative Filtration unit of the model isalso packed with filtering media such as gravels (3-6mm in diameter) that is low in cost, and has a high durability to produceeffluent with lower pollutants and suspended solids content to meet Ghana’s Environmental Protection Agency (EPA) standardsfor the discharge of domestic effluents.

Re-engineering Domestic Septic Tanks into Biogas Tanks

2018 ◽  
Vol 2 (2) ◽  
pp. 54-62
Author(s):  
M. Modjinou, L. Darkwah
Keyword(s):  
Anaerobic Digestion ◽  
Environmental Protection Agency ◽  
Suspended Solids ◽  
Sea Water ◽  
Operating Cost ◽  
Oxygen Demand ◽  
Domestic Sewage ◽  
Green Technology ◽  
Septic Tank ◽  
Septic Tanks

This study is to design a novel septic tank, named Anaerobic Upflow Domestic Septic Tank (AUDST) to recover biogas asenergy and treat domestic sewage. The green technology proposes alternate options to existing Domestic Septic Tanks (DST),encourages anaerobically pre-treatment to reduce bacteria, pollutants, Total Suspended Solids (TSS), Chemical oxygen demand(COD) and Biological oxygen demand (BOD) before the effluent is discharged or is removed by cesspit trucks. Studies haveshown that DST in homes partially treat or just store sewage. Again, these DST have to be emptied from time to time becauseit lack features that will sustain anaerobic activity and usually the sludge is disposed of directly into the sea, water bodies andeven into open places such as “Lavender Hills” without any treatment or disinfection. These practices cause severe public healthand environmental problems. To tackle the challenge at household level, DST are redesigned to treat domestic sewage with lessmanagement, low operating cost, low secondary discharge of pollutants. The proposed new design concept is operated throughthree (3) units: such as desilting, anaerobic digestion and facultative filtration units. The anaerobic digestion stage is made upof baffle and anaerobic filter for accommodating sludge and providing a more intimate contact between anaerobic biomass andsewage which improves treatment performance. The anaerobic unit is fitted with locally woven baskets prefilled with packingmaterials. The aim is to strengthen the biological treatment process at this stage. The Facultative Filtration unit of the model isalso packed with filtering media such as gravels (3-6mm in diameter) that is low in cost, and has a high durability to produceeffluent with lower pollutants and suspended solids content to meet Ghana’s Environmental Protection Agency (EPA) standardsfor the discharge of domestic effluents.

scholarly journals Enhancement of a UASB-Septic Tank Performance for Decentralised Treatments of Storng Domestic Sewage

2017 ◽  
pp. 363-374
Author(s):  
Nidal Mahmoud
Keyword(s):  
Removal Efficiency ◽  
Domestic Sewage ◽  
Septic Tank ◽  
Anaerobic Sludge ◽  
Process Performance ◽  
Reactor Performance ◽  
Septic Tanks ◽  
Long Period ◽  
Removal Efficiencies ◽  
The Difference

The possibility of enhancing the process performance of the UASB-septic tank for treating strong sewage in Palestine by the means of inoculating the reactor with well adopted anaerobic sludge and/or adding a packing media to the upper part of the reactor, thus becoming an AH-septic tank, was investigated. To achieve those objectives, two community onsite UASB-septic tank and Anaerobic Hybrid (AH)-septic tank were operated in parallel at 2 days HRT for around eight months overlapping the cold and hot periods of the year, Palestine. The achieved removal efficiencies of CODtot in the UASB-septic tank and AHseptic tank during the first months of operation, coinciding the cold period and the subsequent months coinciding the hot periods were respectively “50(15) and 48(15)” and “66(8) and 54.73(7.9)”. This shows that the UASB-septic tank performed significantly better (p<0.05) than the AH septic tank after rather long period of operation. The difference in the CODtot removal efficiency was mainly due to the better CODss removal efficiencies in the UASBseptic tank. The removal efficiencies over the last 50 days of operation for CODtot, CODsus, CODcol and CODdis were “70, 72, 77 and 55%” and “53, 54, 78 and 45%” for the UASBseptic tank and AH-septic tank, respectively. Comparing the here achieved COD removal efficiencies with previously reported efficiencies of UASB-septic tanks operated in Palestine shows that the reactor performance has improved substantially by being started with well adopted anaerobic sludge but not by adding a packing media.

DETERMINATION OF PERFORMANCE INDICATORS OF THE TRUCK KrAZ-6510TE

2020 ◽  
pp. 19-26
Author(s):  
Olexandr Pavlenko ◽  
Serhii Dun ◽  
Maksym Skliar
Keyword(s):  
Mathematical Model ◽  
Surface Friction ◽  
Building Structures ◽  
Maximum Torque ◽  
Military Equipment ◽  
Military Vehicles ◽  
Force Magnitude ◽  
Vehicle Mobility ◽  
The Mathematical Model

In any economy there is a need for the bulky goods transportation which cannot be divided into smaller parts. Such cargoes include building structures, elements of industrial equipment, tracked or wheeled construction and agricultural machinery, heavy armored military vehicles. In any case, tractor-semitrailer should provide fast delivery of goods with minimal fuel consumption. In order to guarantee the goods delivery, tractor-semitrailers must be able to overcome the existing roads broken grade and be capable to tow a semi-trailer in off-road conditions. These properties are especially important for military equipment transportation. The important factor that determines a tractor-semitrailer mobility is its gradeability. The purpose of this work is to improve a tractor-semitrailer mobility with tractor units manufactured at PJSC “AutoKrAZ” by increasing the tractor-semitrailer gradeability. The customer requirements for a new tractor are determined by the maximizing the grade to 18°. The analysis of the characteristics of modern tractor-semitrailers for heavy haulage has shown that the highest rate of this grade is 16.7°. The factors determining the limiting gradeability value were analyzed, based on the tractor-semitrailer with a KrAZ-6510TE tractor and a semi-trailer with a full weight of 80 t. It has been developed a mathematical model to investigate the tractor and semi-trailer axles vertical reactions distribution on the tractor-semitrailer friction performances. The mathematical model has allowed to calculate the gradeability value that the tractor-semitrailer can overcome in case of wheels and road surface friction value and the tractive force magnitude from the engine. The mathematical model adequacy was confirmed by comparing the calculations results with the data of factory tests. The analysis showed that on a dry road the KrAZ-6510TE tractor with a 80 t gross weight semitrailer is capable to climb a gradient of 14,35 ° with its coupling mass full use condition. The engine's maximum torque allows the tractor-semitrailer to overcome a gradient of 10.45° It has been determined the ways to improve the design of the KrAZ-6510TE tractor to increase its gradeability. Keywords: tractor, tractor-semitrailer vehicle mobility, tractor-semitrailer vehicle gradeability.

EXPERIMENTAL STUDIES OF CAR PROPERTIES ON A PHYSICAL MODEL

2019 ◽  
pp. 10-16
Author(s):  
Oleksii Timkov ◽  
Dmytro Yashchenko ◽  
Volodymyr Bosenko
Keyword(s):  
Mathematical Model ◽  
Remote Control ◽  
Physical Model ◽  
Model Experiment ◽  
Experimental Studies ◽  
Electrical Energy ◽  
Short Term ◽  
Motor Current ◽  
Memory Card ◽  
The Mathematical Model

The article deals with the development of a physical model of a car equipped with measuring, recording and remote control equipment for experimental study of car properties. A detailed description of the design of the physical model and of the electronic modules used is given, links to application libraries and the code of the first part of the program for remote control of the model are given. Atmega microcontroller on the Arduino Uno platform was used to manage the model and register the parameters. When moving the car on the memory card saved such parameters as speed, voltage on the motor, current on the motor, the angle of the steered wheel, acceleration along three coordinate axes are recorded. Use of more powerful microcontrollers will allow to expand the list of the registered parameters of movement of the car. It is possible to measure the forces acting on the elements of the car and other parameters. In the future, it is planned to develop a mathematical model of motion of the car and check its adequacy in conducting experimental studies on maneuverability on the physical model. In addition, it is possible to conduct studies of stability and consumption of electrical energy. The physical model allows to quickly change geometric dimensions and mass parameters. In the study of highway trains, this approach will allow to investigate the various layout schemes of highway trains in the short term. It is possible to make two-axle road trains and saddle towed trains, three-way hitched trains of different layout. The results obtained will allow us to improve not only the mathematical model, but also the experimental physical model, and move on to further study the properties of hybrid road trains with an active trailer link. This approach allows to reduce material and time costs when researching the properties of cars and road trains. Keywords: car, physical model, experiment, road trains, sensor, remote control, maneuverability, stability.

RESEARCH OF INDICATORS OF A VEHICLE WITH A DIESEL WORKING ON DIESEL AND DIESEL GAS CYCLES USING THE MATHEMATICAL MODEL

2020 ◽  
pp. 14-19
Author(s):  
Serhii Kovbasenko ◽  
Andriy Holyk ◽  
Serhii Hutarevych
Keyword(s):  
Mathematical Model ◽  
Diesel Engine ◽  
Environmental Performance ◽  
Energy Performance ◽  
Dual Fuel ◽  
Fuel System ◽  
Compressed Natural Gas ◽  
Diesel Vehicles ◽  
Diesel Cycle ◽  
The Mathematical Model

The features of an advanced mathematical model of motion of a truck with a diesel engine operating on the diesel and diesel gas cycles are presented in the article. As a result of calculations using the mathematical model, a decrease in total mass emissions as a result of carbon monoxide emissions is observed due to a decrease in emissions of nitrogen oxides and emissions of soot in the diesel gas cycle compared to the diesel cycle. The mathematical model of a motion of a truck on a city driving cycle according to GOST 20306-90 allows to study the fuel-economic, environmental and energy indicators of a diesel and diesel gas vehicle. The results of the calculations on the mathematical model will make it possible to conclude on the feasibility of converting diesel vehicles to using compressed natural gas. Object of the study – the fuel-economic, environmental and energy performance diesel engine that runs on dual fuel system using CNG. Purpose of the study – study of changes in fuel, economic, environmental and energy performance of vehicles with diesel engines operating on diesel and diesel gas cycles, according to urban driving cycle modes. Method of the study – calculations on a mathematical model and comparison of results with road tests. Bench and road tests, results of calculations on the mathematical model of motion of a truck with diesel, working on diesel and diesel gas cycles, show the improvement of environmental performance of diesel vehicles during the converting to compressed natural gas in operation. Improvement of environmental performance is obtained mainly through the reduction of soot emissions and nitrogen oxides emissions from diesel gas cycle operations compared to diesel cycle operations. The results of the article can be used to further develop dual fuel system using CNG. Keywords: diesel engine, diesel gas engine, CNG

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