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EnviroSim is pleased to announce the addition of one-day specialty courses to its training portfolio.
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WE HAVE MOVED! EnviroSim is pleased to announce its relocation to new offices at McMaster Innovation Park.
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NEW POSITION! EnviroSim is always seeking bright, ambitious, educated people to join our company.
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Sydney, Australia BioWin Training Course, scheduled for October 18 - 20, 2010.
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"The BioWin Advantage" e-tech letter : 1-D Settling Models
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EnviroSim to present at 6th International Conference on Sustainable Water Environment on July 31, 2010 in Newark, Delaware
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Introductory and Advanced BioWin Training Courses scheduled for September 13-17, 2010 at the EnviroSim offices in Hamilton, Ontario.
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EnviroSim to present at AETT Specialty Conference – Recent Advances in the Operation & Control of the Activated Sludge Process, July 15, 2010, Leeds, UK.
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EnviroSim is delighted to announce that its latest version of BioWin is now available with Multi-Language capabilities.
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EnviroSim to present at WEF Specialty Conference – Membrane Applications 2010, June 6 – 9, 2010, Anaheim, CA.
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Dwight Houweling becomes latest EnviroSim team member to achieve the Professional Engineer designation.
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"The BioWin Advantage" e-tech letter : Most Popular Biowin User Questions
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Introductory and Advanced BioWin Training Courses scheduled for April 19 - 23, 2010 at the EnviroSim offices in Hamilton, Ontario.
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BioWin Training for Engineering Applications is scheduled for March 16 – 18 at Tongji University, Shanghai PR China
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EnviroSim is pleased to announce the addition of a new team member, Shelley Potter.
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United Kingdom BioWin Training Course scheduled for January 2010.
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EnviroSim is pleased to announce the opening of our European Business.
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The EnviroSim team wishes to thank everyone who made our presence at WEFTEC 09 truly enjoyable.
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Introductory and Advanced BioWin Training Courses scheduled for November 30 - December 4, 2009 2009 at the EnviroSim offices in Flamborough, Ontario.
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EnviroSim is delighted to announce the release of BioWin 3.1, featuring MBR, Microscreen and Cyclone elements as well as a new SBR modeling technique
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EnviroSim is to exhibit at WEFTEC. 09, the 82nd Annual Water Environment Federation Technical Exhibition and Conference, from October 12 to 14, 2009, at McCormick Place, Orlando, FL.
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Melbourne, Australia BioWin Training Course, scheduled for October 26 - 28, 2009.
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EnviroSim is to present at WEFTEC.09, 82nd Annual Water Environment Federation Technical Exhibition and Conference, October 10 to 14, 2009, Orange County Convention Center, Orlando, FL.
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EnviroSim is pleased to announce the addition of a new team member, Leiv Rieger.
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BioWin Seminar and Training scheduled for September 6, 10 & 11, 2009 at the IWA’s Specialized Conference on Nutrient Management in Wastewater Treatment Processes in Krakow, Poland
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EnviroSim to present at IWA Specialized BNR Conference, September 6 - 9, 2009, Krakow, Poland.
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European BioWin User Group Meeting, September 21, 2009, Bordeaux, France.
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EnviroSim to present at 5th IWA Specialised Membrane Technology Conference for Water and Wastewater Treatment, Sep 1 to 3, 2009, Beijing, P.R. China
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EnviroSim contributes to IWA’s Conference on Sustainable Management & Technologies of Sludges, August 8 - 10, 2009, Harbin, PR China.
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EnviroSim launches e-tech letter “The BioWin Advantage”
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Introductory and Advanced BioWin Training Courses scheduled for July 27-31, 2009 at the EnviroSim offices in Flamborough, Ontario.
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EnviroSim to present at WEF Specialty Conference - Nutrient Removal 2009, June 28 – July 1 2009, Washington DC.
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EnviroSim contributes to WEF Specialty Conference – Residuals and Biosolids 2009, Sustainable Biosolids Management, May 3 - 6, 2009, Portland, OR.
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EnviroSim contributes to WEAO 2009 Annual Conference –April 5 - 7, 2009, Toronto, ON.
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Introductory and Advanced BioWin Training Courses scheduled for March 30 - April 3, 2009 at the EnviroSim offices in Flamborough, Ontario.
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Australia and New Zealand BioWin User Group Meeting scheduled for December 10, 2008
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Modeling Workshop in China scheduled for November 18-19, 2008
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Australia and New Zealand BioWin Training Course, scheduled for December 3rd - 5th, 2008
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Australia and New Zealand Calibration of Wastewater Plant Simulators Workshop, scheduled for December 8th - 9th, 2008
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Introductory BioWin Training Course scheduled for January 8-9, 2009 in Las Vegas, Nevada.
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EnviroSim is to exhibit at WEFTEC. 08, the 81st Annual Water Environment Federation Technical Exhibition and Conference, from October 18 to 22, 2008, at McCormick Place, Chicago, IL.
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Introductory BioWin Training Course scheduled for November 17-18, 2008 in Montreal, Quebec.
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EnviroSim is to present at WEFTEC.08, 81st Annual Water Environment Federation Technical Exhibition and Conference, October 18 to 22, 2008, McCormick Place, Chicago, IL.
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EnviroSim to present at IWA World Water Congress and Exhibition, Sep 7 to 12, 2008, Vienna, Austria
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EnviroSim is pleased to announce the opening of our Australian office.
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Introductory and Advanced BioWin Training Courses scheduled for August 25-29, 2008 at the EnviroSim offices in Flamborough, Ontario.
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New Authorized Reseller for Algeria, Libya, Mauritania, Morocco and Tunisia
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Introductory BioWin Training Course scheduled for June 30th - July 1st, 2008 at City College of New York, New York, NY
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United Kingdom Calibration of Wastewater Plant Simulators Workshop scheduled for June 11th - 12th, 2008
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New Zealand Training Course scheduled for May 2008.
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Australian Training Course scheduled for May 2008.
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Introductory and Advanced BioWin Training Courses scheduled for May 5-9, 2008 at the EnviroSim offices in Flamborough, Ontario.
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United Kingdom BioWin Training Course scheduled for April & May 2008
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New Authorized Reseller for Iran.
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EnviroSim contributes to WEF Specialty Conference –Residuals and Biosolids 2008, Traditions, Trends and Technologies, March 30 - April 2, 2008, Philadelphia, PA.
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EnviroSim to present at CAWQ Symposium on Water Quality Research, February 11 – 12, 2008, Burlington, Ontario.
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EnviroSim is delighted to announce the release of BW Controller for whole-plant process control simulation.
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Introductory and Advanced BioWin Training Courses scheduled for February 25-29 at the EnviroSim offices in Flamborough, Ontario.
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EnviroSim is pleased to announce BioWin 3 enhancements
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WEFTEC 07: A thank you from the EnviroSim Team at WEFTEC.07
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EnviroSim is pleased to announce the return of Dr Chris Bye from sabbatical in Australia.
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United Kingdom BioWin User Group Meeting scheduled for November 22, 2007.
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EnviroSim is to exhibit at WEFTEC.07, 80th Annual Water Environment Federation Technical Exhibition and Conference, October 13 to 17, 2007, San Diego Convention Center, San Diego, CA.
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EnviroSim is to present at WEFTEC.07, 80th Annual Water Environment Federation Technical Exhibition and Conference, October 13 to 17, 2007, San Diego Convention Center, San Diego, CA.
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EnviroSim is pleased to announce the addition of a new team member, Dwight Houweling.
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*UPDATE* BOTH COURSES NOW FULL : Introductory and Advanced BioWin Training Courses scheduled for October 29 - November 2, 2007 at the EnviroSim offices in Flamborough, Ontario.
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EnviroSim to present at 2007 Senior Technologic Forum on Water Industry, August 3 - 4, 2007, Beijing, China
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EnviroSim to present at Particle Separation Conference (PS 2007), July 9-12, 2007 in Toulouse, France.
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EnviroSim to present at International Workshop on Monitoring and Sensor for Water Pollution Control, June 13-14, 2007, Tsinghua University, Beijing, China.
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Introductory and Advanced BioWin Training Courses scheduled for July 23-27, 2007 at the EnviroSim offices in Flamborough, Ontario.
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EnviroSim to present at WATERMATEX 2007, May 7 – 9, 2007, Washington, DC.
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United Kingdom BioWin Training Course scheduled for June, 2007
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EnviroSim to present at CLONIC PROJECT workshop, April 19 – 20, 2007, Barcelona, Spain.
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EnviroSim to present at WEF / AWWA Specialty Conference – Joint Residuals and Biosolids Management Conference 2007, Biosolids and Residuals: Innovation and Sustainability, April 15 – 18, 2007, Denver, CO.
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EnviroSim to present at WEF / IWA Specialty Conference - Nutrient Removal 2007, The State of the Art, March 4 - 7 2007, Baltimore, Md.
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EnviroSim is delighted to announce the release of BioWin 3 which now includes Biofilm and Sidestream modeling
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Introductory and Advanced BioWin Training Courses scheduled for April 23-27, 2007 at the EnviroSim offices in Flamborough, Ontario.
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EnviroSim is pleased to announce the addition of a new team member, Zhirong Hu
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EnviroSim is pleased to welcome visiting Professor Yves Comeau
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Introductory and Advanced BioWin Training Courses scheduled for January 29 - February 2, 2007 at the EnviroSim offices in Flamborough, Ontario.
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WEFTEC 06: References to BioWin section expanded and a thank you from the EnviroSim Team
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Australian Training Course scheduled for December, 2006
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EnviroSim is to exhibit at WEFTEC.06, 79th Annual Technical Exhibition and Conference, October 21 to 25, 2006, Dallas Convention Center, Dallas, TX.
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New Authorized Reseller for France.
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United Kingdom BioWin Training Course scheduled for September, 2006.
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South Africa BioWin Training Course scheduled for August, 2006.
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EnviroSim to present at IWA Specialized Conference, Biofilm VI, 24 to 27 Sep 2006, Amsterdam, The Netherlands.
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EnviroSim to present at IWA World Water Congress and Exhibition, Workshops & Courses, Sep 7 to 14, 2006, Beijing, PR China.
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New Authorized Reseller for Egypt, Saudi Arabia, United Arab Emirates, Oman, Yemen and Tunisia.
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Australian and New Zealand BioWin Training Courses scheduled for July and November, 2006
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Introductory BioWin Training Course scheduled for July 10th - 11th, 2006 at the EnviroSim offices in Flamborough, Ontario.
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Calibration of Wastewater Plant Simulators Workshop, scheduled for June 19th - 20th, 2006 at the EnviroSim offices in Flamborough, Ontario
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Advanced BioWin Training Course scheduled for April 24th - 25th, 2006 at the EnviroSim offices in Flamborough, Ontario
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Introductory BioWin Training Course scheduled for March 6th - 7th, 2006 at the EnviroSim offices in Flamborough, Ontario
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SBR System Considerations

Three aspects inherent to SBR systems require special consideration:

à Steady State with SBR Systems   à Sludge Age or SRT in SBR Systems
à Cycle Offsets

Steady State with SBR Systems
SBR systems necessarily are dynamic, and the concept of steady state is not relevant. However, if we operate an SBR system with a fixed influent loading the SBR system will attain a quasi "steady state". [Note: the input could be either a Constant Input or a Variable Input]. That is, the SBR system response would be repeated identically from cycle to cycle, where the term "cycle" refers to the longest cycle in the dynamic system [not necessarily the cycle time of the SBR]. For example, the cycle time of a Variable Input influent element typically would be 24 hours, and this would be the quasi steady state cycle time (provided of course that the SBR cycle time is less than 24 hours which usually is the case). Even with a Constant Input, the quasi steady state "cycle" time may differ from the SBR cycle time. For example, perhaps wastage only occurs every third cycle; in this case the steady state "cycle" time will be three times the cycle time of the SBR.

A general guideline for the time a dynamic system takes to reach a quasi "steady state" is three to four times the longest time constant in the system. In the case of activated sludge systems usually the longest time constant will be the sludge age (or SRT). For SBR systems it is difficult to calculate an exact SRT so it is suggested that the appropriate procedure to identify when "steady state" is reached is by simulating for an extended period while viewing the TSS response.

When setting up an SBR system it is suggested that you first simulate for an extended period until you attain a quasi "steady state". Then save the file. When you re-open the file at a later time, you start off from the "steady state" [by running the dynamic simulation from Current values when the dynamic simulation is started.

Sludge age or SRT in SBR Systems
Sludge age (or SRT) is defined as the mass of sludge in the system divided by the mass of sludge wasted per day. In practice sludge likely will be wasted from an SBR towards the end of the settle/decant phase. At this time the sludge concentration is high and the waste volume will be lowest for a given mass wasted.

Design of activated sludge systems usually is based on some notion of a desired SRT. Experience with simulating SBRs indicates that it is difficult to estimate a required wastage rate for the target SRT if wasting occurs during settle/decant. This difficulty is related to a number of factors: quantifying the mass of sludge in the system, the sludge compactability, the changing sludge concentration at the base of the SBR during settle/decant, and the possibility of "rat holing" if the wastage rate is high.

For simulation purposes it is simpler to achieve a desired SRT with reasonable accuracy through setting up the system for hydraulic SRT control; that is, wasting of mixed liquor during the mixed phase rather than wasting settled sludge. For example, setting an SRT of 10 days requires wasting one tenth of the mixed reactor contents (volume) each day. Even this approach is not explicitly suited to SBR systems because the liquid hold-up and mixed liquor solids concentration likely changes from cycle to cycle. However, consideration of the liquid volume response usually allows a reasonable estimate of the volume of mixed liquor to waste so as to attain a given SRT. For example, consider an SBR with a maximum volume of 20 ML that is operated with 4 cycles per day, and decanted to 50% of the maximum each cycle. A trial simulation will provide an estimate of the average hold-up at the end of each cycle; say this is 16 ML. To attain an SRT of approximately 10 days requires wasting 1.6 ML of mixed liquor each day, or 0.4 ML/cycle. In this case we could set up the wastage to operate over the last 15 minutes of the mixed period in each cycle, at a rate of 1.6 ML/h (i.e. 38.4 ML/d for 15 minutes).

Hint: In certain SBR configurations there is recycling of sludge (usually only during the mixed phase) from the decant zone to an upstream pre-zone or reactor. This recycle can be set up using the SBR underflow. Wasting of mixed liquor is achieved via a splitter in the recycle stream, as shown in the view below.

SBR Waste Scheme
-SBR with recycle and wasting from the recycle-

SBR System Cycle Offsets
Individual units in parallel-unit SBR systems usually operate with the same cycle times of fill, react, settle and decant. However, the cycles are staggered in time. This is achieved readily in BioWin through offsets.

Hint: Select the unit that first receives influent as the reference (zero offset). An offset is specified for each of the other units. Think of the offset as the "time into the cycle" for that unit when the reference unit first receives influent.

Consider the four SBR system shown below. Each unit operates on the same cycle, with equal periods for fill, react, settle and decant (1 hour each, with a total cycle time of 4 hours, and 6 cycles per day). Influent to the system is directed sequentially to each of the four units for a fill period of one hour. That is, SBR #1 receives influent for 1 hour (while SBR #2 is decanting, SBR #3 is settling, and SBR #4 is reacting). At the end of the hour influent is directed to SBR #2 and each of the SBRs moves to the next stage in its cycle (SBR #1 starts the react period, SBR #3 starts decanting, and SBR #4 starts settling). Offsets will be specified as follows: SBR #1 is the reference; SBR #2 must be 3 hours "into the cycle" because in one hour it will receive influent; and so on. In summary:


Unit

Offset (hours)

SBR #1

Zero

SBR #2

3

SBR #3

2

SBR #4

1


Multiple SBR's with Offsets
-Four-in-Parallel System-

     

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