Experience with the Relay Procedure for Tuning Controllers in Automatic Control of Chlorination

1993 ◽  
Vol 28 (11-12) ◽  
pp. 257-261
Author(s):  
M. Truett Garrett ◽  
Zaki Ahmad ◽  
Shelly Young
Keyword(s):  
Wastewater Treatment ◽  
Automatic Control ◽  
Time Constant ◽  
Wastewater Treatment Plants ◽  
Relay Feedback ◽  
Quality Of Control ◽  
Incomplete Mixing ◽  
Long Time ◽  
Chlorine Demand

The recent requirements by U.S.E.P.A. for dechlorination and biomonitoring have increased the importance of automatic control of effluent chlorination in wastewater treatment plants. Difficulties with the Ziegler-Nichols controller tuning procedure were reported at the Kyoto Workshop, 1990. Problems are caused by the noise of incomplete mixing, a long time constant, and the disturbances of changing flow and chlorine demand. The Astrom-Hagglund relay feedback procedure provides acceptable control while data is logged to determine the controller constants. Experiences in using the procedure in existing facilities (not redesigning the mixing point) and the quality of control are presented.

Automatic buffer capacity based sensor for effluent quality monitoring

1996 ◽  
Vol 33 (1) ◽  
pp. 81-87
Author(s):  
L. Van Vooren ◽  
P. Willems ◽  
J. P. Ottoy ◽  
G. C. Vansteenkiste ◽  
W. Verstraete
Keyword(s):  
Wastewater Treatment ◽  
Buffer Capacity ◽  
Wastewater Treatment Plants ◽  
Data Interpretation ◽  
Full Scale ◽  
Quality Monitoring ◽  
Effluent Quality ◽  
Capacity Curves ◽  
On Line

The use of an automatic on-line titration unit for monitoring the effluent quality of wastewater plants is presented. Buffer capacity curves of different effluent types were studied and validation results are presented for both domestic and industrial full-scale wastewater treatment plants. Ammonium and ortho-phosphate monitoring of the effluent were established by using a simple titration device, connected to a data-interpretation unit. The use of this sensor as the activator of an effluent quality proportional sampler is discussed.

scholarly journals Long-term investigation of phosphorus removal by iron electrocoagulation in small-scale wastewater treatment plants

2018 ◽  
Vol 78 (6) ◽  
pp. 1304-1311 ◽  
Author(s):  
I. Mishima ◽  
M. Hama ◽  
Y. Tabata ◽  
J. Nakajima
Keyword(s):  
Wastewater Treatment ◽  
Phosphorus Removal ◽  
Wastewater Treatment Plants ◽  
Phosphorus Release ◽  
Small Scale ◽  
Operational Conditions ◽  
Long Time ◽  
Negative Effect ◽  
Iron Electrolysis

Abstract Small-scale wastewater treatment plants (SWTPs), called Johkasou, are widely used as decentralized and individual wastewater treatment systems in sparsely populated areas in Japan. Even in SWTPs, nutrients should be removed to control eutrophication. An iron electrolysis method is effective to remove phosphorus chemically in SWTPs. However, it is necessary to determine the precise conditions under which phosphorus can be effectively and stably removed in full scale SWTPs for a long period. Therefore, long-term phosphorus removal from SWTPs was investigated and optimum operational conditions for phosphorus removal by iron electrolysis were analyzed in this study. Efficient phosphorus removal can be achieved for a long time by adjusting the amount of iron against the actual population equivalent. The change of the recirculation ratio had no negative effect on overall phosphorus removal. Phosphorus release to the bulk phase was prevented by the accumulated iron, which was supplied by iron electrolysis, resulting in stable phosphorus removal. The effect of environmental load reduction due to phosphorus removal by iron electrolysis was greater than the cost of power consumption for iron electrolysis.

scholarly journals Methods of reconstruction and modification of the sequencing batch reactor at municipal wastewater treatment plants in Vietnam

Vestnik MGSU ◽  
2019 ◽  
pp. 589-602 ◽  
Author(s):  
Tran Ha Quan ◽  
Elena S. Gogina
Keyword(s):  
Wastewater Treatment ◽  
Sequencing Batch Reactor ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Batch Reactor ◽  
Municipal Wastewater Treatment ◽  
Wastewater Purification ◽  
Municipal Wastewater Treatment Plants ◽  
Operation Cycle

Introduction. Vietnamese urban municipal wastewater treatment plants are mainly of aeration-type facilities. Nowadays, an aeration-type plant, the Sequencing Batch Reactor (SBR), is widely applied and possesses a number of advantages over traditional systems with suspended activated sludge. Advantages of the SBR are mainly concluded in simplicity of operation, occupied area and cost. There is a number of problems at the wastewater treatment plants; they are connected with supplying only a half of wastewater design amount for the treatment as well as with quality of the purified water that must satisfy requirements of the Vietnamese discharge standard, the Standard A. Therefore, reconstruction and modification of the SBR is the major challenger to ensure the sustained development of large Vietnamese cities and maintenance of ecological balance. Materials and methods. To enhance the efficiency of wastewater purification in the SBR, the experiments were set on reactor reconstruction and modification by two directions: (1) Technological method, i.e. applying the Biochip 25 biocarrier, and (2) Operation method, i.e. adding the anoxic phase in reactor operation cycle. Laboratory tests were conducted for each of the directions, including comparison of a typical reactor with the modified one. Results. The study resulted in obtaining an optimal amount of the BioChip biocarrier material (10 to 20 %) that increased efficiency of wastewater purification by 10 to 20 %. In addition to this, when creating an anoxic phase of the operation cycle, efficiency of nitrogen removal increased by 20 %. When the denitrification occurs under the anoxic conditions, it contributes to stabilization of ammonium nitrogen removal for daily nitrogen loading in reactor of 0.3 to 0.8 TKN kg/sludge kg. Conclusions. The suggested technology provides the quality of treated water corresponding with the Vietnamese Standard A requirements. At the present, it is planned to proceed with the experiment on the base of Vietnamese semi-industrial plant for research and appraisal of the SBR reconstruction and modification method. Acknowledgements. The authors are grateful to AKVA Control company in Samara for granted biocarrier Mutag BioChip 25 and to Associate Professor Tran Van Quang and his students, Nguyen Ngoc Phuong and Truong Quoc Dai, of Environment Protect Research Center, Danang University for support of the experiment.

scholarly journals A simple model of wastewater treatment plants for managing the quality of the Seine River

2018 ◽  
Vol 51 (18) ◽  
pp. 880-885 ◽  
Author(s):  
C.E. Robles-Rodriguez ◽  
J. Bernier ◽  
V. Rocher ◽  
D. Dochain
Keyword(s):  
Wastewater Treatment ◽  
Simple Model ◽  
Wastewater Treatment Plants ◽  
Seine River

Improving the effluent of small wastewater treatment plants by bacteria reduction and nutrient removal with an algal biofilm

2003 ◽  
Vol 48 (2) ◽  
pp. 373-380 ◽  
Author(s):  
G. Schumacher ◽  
I. Sekoulov
Keyword(s):  
Wastewater Treatment ◽  
Nutrient Removal ◽  
Wastewater Treatment Plants ◽  
High Potential ◽  
High Quality ◽  
Secondary Pollution ◽  
Algal Biofilm ◽  
Biofilm Process ◽  
Suspended Algae

In wastewater ponds, bacteria numbers decrease considerably in the case of raised algae concentrations in the effluent. This shows that algae have a high potential for bacteria reduction in wastewater. Simultaneously, algae remove nutrients from the water for the formation of biomass. However, suspended algae also cause a high secondary pollution in the effluent of wastewater treatment plants. By using attached algae, as they are frequently observed as an algal biofilm in the effluent of wastewater treatment plants, the problem of separation of algae and water can be avoided. Furthermore, the algae can be removed simply from the water. In this study the possibilities for bacteria reduction and nutrient removal were examined with the aid of an algal biofilm. The results show that an algal biofilm process can be used for cases where small amounts of wastewater should be treated and a high quality of the effluent should be attained.

Lessons learnt from the application of a multi-variable controller for nitrogen removal in the Mekolalde wastewater treatment plant: good simulation practices in control

2014 ◽  
Vol 69 (6) ◽  
pp. 1289-1297 ◽  
Author(s):  
I. Irizar ◽  
S. Beltrán ◽  
G. Urchegui ◽  
G. Izko ◽  
O. Fernández ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Nitrogen Removal ◽  
Wastewater Treatment Plants ◽  
Treatment Plant ◽  
Real Life ◽  
Control Product ◽  
Quality Of Water ◽  
Short Period ◽  
Mathematical Modelling And Simulation

Although often perceived as tools for use by scientists, mathematical modelling and simulation become indispensable when control engineers have to design controllers for real-life wastewater treatment plants (WWTPs). Nonetheless, the design of effective controllers in the wastewater domain using simulations requires effects, such as the nonlinearity of actuators, the time response of sensors, plant model uncertainties, etc. to have been reproduced beforehand. Otherwise, control solutions verified by simulation can completely underperform under real conditions. This study demonstrates that, when all the above effects are included at the outset, a systematic use of simulations guarantees high quality controllers in a relatively short period of time. The above is exemplified through the Mekolalde WWTP, where a comprehensive simulation study was conducted in order to develop a control product for nitrogen removal. Since its activation in May 2011, the designed controller has been permanently working in the plant which, from this time onwards, has experienced significant improvements in the quality of water discharges combined with a lower utilization of electricity for wastewater treatment.

scholarly journals The small Wastewater Treatment Plants – Hydrobotanical Systems in Environmental Protection

2013 ◽  
Vol 39 (1) ◽  
pp. 3-16 ◽  
Author(s):  
Katarzyna Pawęska ◽  
Krzysztof Kuczewski
Keyword(s):  
Wastewater Treatment ◽  
Constructed Wetland ◽  
Mechanical Treatment ◽  
Wastewater Treatment Plants ◽  
Treatment Plant ◽  
Domestic Sewage ◽  
Septic Tank ◽  
Educational Institutions ◽  
Wetland Treatment

Abstract The paper presents results of research concerning operating of five small wastewater treatment plants working in two different technologies: hydrobotanical wastewater treatment plant and constructed wetland. Each object was designed for the treatment of domestic sewage after preliminary mechanical treatment in a septic tank. Hydrobotanical wastewater treatment plants and one of constructed wetland beds were built for treating sewage produced in educational institutions and resort. In the article attention is paid to possibility of exceeding the maximum allowable concentration of pollutants for three main indicators of pollution: BOD5, COD, and total suspension. The reduction of these indices is required by the Regulation of the Minister of Environment [14] for wastewater treatment plants with PE < 2000. In addition, the paper presents the effects of wastewater treatment to reduce biogens. The best quality of outflow was reached by outflows from constructed wetland treatment plants. None of the observed objects fulfilled the requirements in terms of allowable concentrations for total suspension. The most effective were objects operating in technology of “constructed wetland”.

Automatic control and remote monitoring system for biological nutrient removal on small wastewater treatment plants in Korea

2004 ◽  
Vol 50 (6) ◽  
pp. 199-206 ◽  
Author(s):  
H. Lee ◽  
Y.M. Min ◽  
C.H. Park ◽  
Y.H. Park
Keyword(s):  
Wastewater Treatment ◽  
Automatic Control ◽  
Monitoring System ◽  
Remote Monitoring ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Biological Nutrient Removal ◽  
Time Interval ◽  
Efficient Operation ◽  
Remote Monitoring System

Many small-size wastewater treatment plants in KoreaÕs rural communities are designed to remove organic and suspended matter only, and they generally show a large fluctuation in the influent loading compared to municipal wastewater treatment plants (MWWTPs). They also have no professional engineers stationed for efficient operation against mechanical breakdown. For those reasons, the wastewater treatment plants have low efficiency in treatment of nitrogen and phosphorus as well as organic matter. In order to solve those problems, this study developed an automatic control system and RMS (remote monitoring system), which can keep efficiency stable despite any change in the small plants' loading rates and are capable of removing nutrient materials such as nitrogen or phosphorus. According to the results of the Experimental SBR system of the automatic control program, complete nitrification was made under oxic conditions and denitrification occurred as NO3-N concentration decreased by 0.5 mg/l in anoxic conditions and excellent nitrogen removal efficiency was seen generally. The Experimental SBR system created “phosphate release and uptake” effectively and displayed phosphate-removing efficiency up to more than 80% as the concentration of effluent was kept low by 0.4 mg/l. RMS developed in this study transmits a plants data and operation states to clients in remote locations in real-time interval through the Internet. Therefore, although you are in a remote location, it allows you to see if a plant is properly operated or there is any breakdown.

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