PetWin32 is a Microsoft Windows-based simulator used in the analysis and design of petroleum and petrochemical industry wastewater treatment plants. The figure below shows an example of a nitrogen removal system configuration set up in PetWin32. Many different process units can be included to "build" a specific treatment plant configuration; for example:

  • Various influent elements for setting up wastewater inputs or methanol addition streams.
  • Equalization tanks.
  • Continuous flow bioreactors incorporating sophisticated means for simulating the performance of diffused aeration systems.
  • Variable volume / batch bioreactors.
  • Various sequencing batch reactor (SBR) modules: single tank units, or SBRs with one or two hydraulically-linked prezones that are either continuously mixed or that allow settling of solids when the decant zone is in a settling phase.
  • Aerobic digesters.
  • Grit removal tanks.
  • Primary settling tanks.
  • Secondary settling tanks, where solids removal performance is either specified by the user, or where sludge settling behavior is based on flux theory using a one-dimensional model.
  • A generic dewatering unit where the user specifies both solids capture and flow split between the thickened and un-thickened streams. This unit can be applied to simulating a range of dewatering processes such as centrifuges, belt presses, dissolved air flotation units, etc.
  • Mixers and splitters for directing flow between units in the configuration. The user has full flexibility for specifying details of splits in streams (by actual rate, fraction, ratio, flow pacing, according to a timed schedule, etc.).

Example of a process configuration set up in PetWin32.

The facility to view simulation results rapidly, and in detail, is of paramount importance in the design and analysis of systems. PetWin32 incorporates an Album for this purpose. The Album consists of a series of tabbed pages (somewhat like recent spreadsheet programs) showing simulation results in tabular and/or graphical format. The figure below shows example views of Album pages.

PetWin32 offers a number of features to aid in creating attractive, professional reports, and includes its own internal Notes editor to help keep track of project details. It is very easy to get results from PetWin32 into a word processor or spreadsheet. Charts, tables, system configuration layouts, etc. can be copied and pasted from PetWin32 to reports. Tables can be exported as tabbed text and then quickly converted to tables.

Examples of Album pages in PetWin32 (click images to see larger views).

An Album page showing a Pie Chart

Feature Tour


This document highlights some of the features available in the latest version of PetWin. Major topics of interest include:


PetWin32 Purchase & Leasing Options

Outright Purchase Option

The basis for the purchase scheme is as follows:

  1. Permanent license;
  2. One year of telephone and email software support;
  3. Future software updates will be offered for purchase;
  4. Manual (including tutorials) in electronic form - users can print their own.

    Renewable Lease Option

    The software license is leased for one year.

    The basis for the lease scheme is as follows:

    1. Renewable one-year license;
    2. Telephone and email software support;
    3. All software updates free - users pay a nominal shipping and handling fee;
    4. Manual (including tutorials) in electronic form - users can print their own;
    5. First-time users must undertake to lease the software for three (3) years.

    Non-lease PetWin32 Upgrade Option

    PetWin32 users who exercise the Outright Purchase Option (Option A) may upgrade to the latest version.

    Educational Pricing

    There are academic licenses offered to Universities at considerable discounts to the price for "commercial" users such as consulting engineers and municipalities. Universities may purchase PetWin32 (minimum order of 3 copies). The intent is that academic licenses are used in the context of education. Specifically, academic licenses may NOT be used for contract research or to provide consulting services.

    The essence of the PetWin32 academic license is that:

    1. The software is used for educational purposes only.
    2. The software may be used by bona fide students and University employees for educational and teaching purposes only.
    3. The software may not be used to provide services (paid or un-paid) to municipalities or consulting engineers. Universities wishing to provide these services must purchase a commercial software license.

    In the event that the University or any of its representatives (students, staff, faculty members) wishes to use PetWin32 for "commercial" purposes (including contract research), then arrangements for the purchase of a commercial license must be made.

    Upgrades to university copies may be purchased.


    Free software support. We can do this because we have so few users with problems. The simplest way to provide support is via email. The files for a particular system are not large, and it is very simple to send these to us as attachments to an email. In this way we can be viewing the exact system which a user is working on.

    It should be pointed out that we do not provide free process consulting services. This can be explained with an example:

    Software Support Process Consulting Support
    A user may ask the question: "How do I save a file in PetWin32?". This is a software support question, and we would respond: "Click on Save in the File menu, type in a name, and then click OK.". This type of support is provided with no charge. We get very few software support questions due to the intuitive user interface. A user may ask the question: "I am running a simulation and the effluent nitrate is 7 mg/L, but it must be less than 5 mg/L. What must I do?". We regard this as a process consulting question rather than a software support question. In many instances we are involved with PetWin32 users addressing these questions, but not as free software support.


    PetWin32 is very easy to learn. With the online tutorials and resources in the online help, an engineer only needs a few hours of familiarization. However, the most efficient way to get young engineers up to speed is through an intensive training course which covers PetWin32 as well as touching on various process engineering aspects. We have run many PetWin32 training courses, and suggest the following format:

    • Two day (16 hour) course.
    • The course is hands-on and consists of a series of case studies designed to demonstrate PetWin32 features.
    • The orientation of the case studies leans towards nutrient removal systems, but many of the topics are quite general. An associated focus is wastewater characterization and estimation/measurement of these characteristics as well as nitrification rates.
    • We supply course manuals and a number of spreadsheets used as "tools".
    • We find the optimum size group of attendees to be in the range of 6 to 12 with two persons per PC (e.g. 6 PCs for a group of 12).
    • The client provides the venue, the necessary number of PCs, a screen (or wall) and a projection device for connection to our portable PC (e.g. InFocus-type rather than panel on overhead projector).
    • In many cases we offer the course over a Friday/Saturday so that there is less impact on "billable time" for the consultant, and usually airfares are reduced.

    The cost for the course is to be discussed per case, plus direct expenses (airfare, two nights hotel, etc.). In the case of clients outside North America we generally can combine several visits in one trip, thereby reducing the air travel cost to each client.