WatPro - Premier Water Treatment Simulator

WatPro Version 2 features modeling disinfection with chlorine dioxide.

• Calculated Turbidity Reductions by Process & Whole Facility
• Calculated Specific UV Absorbance (SUVA) in Raw Water
• New Utilities (calculator, file recall, notepad)
• Improved Reporting and Calibration Options
• Models CLO2 Disinfection, Consumption & DBP Formation
• Includes Use of Ferrous Salts for Removing Residuals

It's easy to configure your plant processes in WatPro.
Use WatPro to:

• minimize formation of DBPs (e.g. THMs, HAAs, chlorite, chlorate)
• compare inactivation of viruses and Giardia by chlorine, ozone, chlorine dioxide and chloramines
• calculate Ct for any location in the treatment system
• optimize plant operation by allowing chemical addition points to be varied or by tank baffling
• estimate treated water quality for a proposed change in plant operation.

WatPro has a user-friendly interface that allows a schematic of the water treatment plant to be easily configured within minutes. Results can be viewed either on-screen, printed a user-formatted hard copy report or saved to electronic files for further processing.

WatPro treatment processes

• Flocculation tanks
• Settling tanks
• Channels
• Filters
• Membrane processes
• Granular activated carbon
• Contact chambers
• Clear wells
• Reservoirs.

WatPro is a highly effective instructional and training tool

WatPro is so instructive and easy to use that it has been adopted as a teaching tool in university courses in Canada and England. It has also been accepted for use in a laboratory assignment in the forthcoming Laboratory Manual published by the Association of Environmental Engineering and Science Professors.

WatPro offers powerful features to help you obtain timely information:

• SCADA system links for continuous system performance monitoring
• sensitivity analysis to evaluate the effects of chemical or process changes
• site-specific calibratable chemical reaction rates (e.g. chlorine decay)
• user-formatted reports

Potentially carcinogenic disinfection by-products (DBPs) are a growing concern for water utilities as regulations such as the Disinfection-Disinfection By-Product Rule impose more stringent DBP limits. In addition, compliance may be difficult and costly to achieve while maximizing disinfection efficiency for Giardia and Viruses. WatPro is a water treatment plant simulator which can be calibrated specifically for your plant and can help you manage your treatment process to balance compliance with both DBP and microbial regulations while achieving potential cost savings.

Unit Processes Include:

• Disinfectant Addition (Cl2, ClO2, O3, NH2Cl)
• Chemical Addition
• (pH adjusting, flocculation)
• Mixing tank
• Flocculator
• Sedimentation
• Filters
• Clear well
• Reservoir

Benefits Include:

• Optimize water treatment processes
• Minimize DBP formation
• Ensure effective disinfection
• Increase consumer confidence
• Reduce expensive lab and pilot studies
• Potential savings on disinfectant costs
• Improve operator skills
• Respond to changing water quality
• Evaluate process changes
• Facilitate regulatory changes
• Real-time simulation via SCADA link

Features Include:

• Site-specific model calibration
• Field tested simulation models
• Optional Link to SCADA system
• Easy to use Windows interface
• Extensive online help system
• Built-in sensitivity analysis
• Comprehensive documentation

WatPro and Inactivation of E. Coli Bacteria

WatPro allows users to track Ct at all locations in a treatment plant.

Here is why you should be working with WatPro right now!

A deadly microbial invasion in a Canadian water distribution system has tragically illustrated the need to ensure that consumer tap water is absolutely safe. WatPro can show whether pathogenic bacteria like E. coli 0157:H7 have been adequately inactivated in a water treatment plant. For an uninterrupted primary disinfectant dosage rate, WatPro tracks the inactivation of viruses and Giardia by disinfectant addition.

Because fecal coliform bacteria are inactivated by disinfectants to a greater extent than viruses, the log reduction of bacteria like E. coli will match or exceed the reduction for viruses calculated by WatPro.

The simulator also determines the Ct disinfection parameter at any location in the treatment plant.

Advantages of Chlorine Dioxide

The substitution of chlorine by chlorine dioxide as a disinfectant in drinking water treatment is of growing interest. While chlorine has been effective for reducing most microbial pathogens to safe levels, it reacts with naturally-occurring matter in the water to form trihalomethanes (THMs) and haloacetic acids (HAAs) as disinfection by-products (DBPs). In December, 1998, the U.S. EPA finalized the Stage1 Disinfectants/Disinfection By-product (D/DBP) Rule setting a maximum allowable concentration for total THMs of 0.080 mg/L, and for the sum of five HAAs at 0.06 mg/L. The maximum allowable concentration for chlorine in the treated water is 4.0 mg/L. Among the reported advantages of chlorine dioxide over chlorine are a better ability to inactivate Cryptosporidium cysts, and elimination of the formation of THMs and HAAs.

Concerns

Although chlorine dioxide does not produce THMs and HAAs, it does produce a different set of disinfection by-products, chiefly the chlorite ion, as well as lower concentrations of the chlorate ion. Typically, the ClO2 reacts either with dissolved organic matter, or with dissolved metals such as manganese (II), to accept an electron and become a chlorite ion. Chlorate ion may form due to reaction of the chlorite ion with hypochlorous acid present as an impurity in chlorine dioxide generators. As a rule of thumb, the concentration of chlorite formed is in the range of 50 to 70 % of the applied ClO2 dose. The maximum residual disinfectant level for chlorine dioxide set by the U.S. EPA in the Stage 1 D/DBP Rule is 0.8 mg/L. Under the same rule, the maximum allowable contaminant level (MACL) for chlorite is 1.0 mg/L.

Chlorine Dioxide Modeling in WatPro

In WatPro, the models for consumption of ClO2, and formation of chlorite and chlorate are taken from newly published university research. The expressions are expressed as functions of water quality and chlorine dioxide related parameters, including:

temperature

• pH
• water organic content
• contact time, and
• chlorine dioxide dose

As well, significant 2-factor interaction terms are included in the relationships.

The model equations were developed from testing with 8 different waters sources, and then validated with an external data set from waters throughout North America (Ann Arbor, MI, Vancouver, BC, Calgary, AB and Brantford, ON). The inactivation of Giardia and viruses by ClO2 in WatPro are calculated by a polynomial interpolation routine. The procedure estimates the log reduction of the microorganisms by fitting the calculated Ct parameter to a polynomial expression derived from inactivation tables in the EPA’s Surface Water Treatment Rule (EPA, 1989).

WatPro is very useful in the evaluation of the substitution of chlorine by chlorine dioxide. Through modeling, one can determine microbial reductions and levels of DBPs formed at comparable disinfectant doses. Once the doses of disinfectants are known, cost comparisons may be conducted to see which is the most cost-effective.