WWTP modelling that does it all

Develop digital twins, implement new control strategies and optimise plant operations using WEST, our open and flexible software platform for advanced process modelling and statistical analyses


Compare and verify design alternatives for new WWTPs

Evaluate the performance of a selected WWTP through pre-defined and custom indicators under realistic dynamic conditions. Compare multiple design alternatives with respect to effluent quality, investments and operational costs. Run automated simulations, identify optimal design and verify performance under various boundary conditions using the Advanced Experiments tools (Uncertainty Analysis, Scenario Analysis and Parameter Estimation).

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See how WEST compares MLE, Bardenpho and UCT process configurations for a municipal WWTP

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Watch WEST transform an existing facility’s phosphorus removal process

Optimise and upgrade existing treatment facilities

Develop and calibrate detailed dynamic process models to emulate existing systems and processes. Identify optimal operational strategies, configure and virtually test new processes from these baseline models. Inform operational staff of optimal setpoints for control or to evaluate the efficacy of a new process. Implement plant-wide models and integrate different layers (water line, sludge line, energy, control) to holistically evaluate and optimise plant operations. Facilitate the transition from treatment plants to resource recovery facilities.

Develop custom process models and new processes unit blocks

Access your model using a Gujer Matrix Editor or a conventional Code Editor to develop custom models that include processes and components not typically described in traditional models. Create new process unit blocks and incorporate custom models using a dedicated Block Editor. Virtually test the performance of a novel biological treatment process unit designed with unique hydraulic characteristics and operating stages. Develop a new model block with customised input, hydraulic properties and biokinetic conversion processes (namely, modifications to standard Activated Sludge Models).

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Track the effect of toxic chemical in a biological treatment system

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See customised control algorithms developed in WEST

Implement advanced control strategies with unlimited capabilities

Evaluate various operational strategies prior to implementation with flexible control models. Automatically convert Matlab fuzzy logic controllers. Build fully customisable control systems using multiple control blocks that communicate with one another. Easily navigate the model library and customise control blocks to fit plant-specific nuances in operation and control using the built-in Model Editor. Benefit from built-in templates as well as inline syntax check and error detection, code snippets and code verification.

Run complex, integrated models on one software platform

Perform complex simulations of integrated systems including catchments, collection systems and recipients (watersheds, rivers) for long-term, computationally intensive simulation periods. Connect WEST to user-defined pre- and post-processing tools or third-party models following successful model configuration. Take advantage of new tools for semi-automatic model calibration and process optimisation will also soon be available as computational and numerical methods advance in the field of data analytics and processing.

Use the catchment, sewer and river models of WEST to simulate Integrated Urban Water Systems

Make WEST your choice modelling platform

Plant Operators

Investigate the complex process dynamics and interactions that characterise a modern WWTP. Evaluate treatment performance resulting from changes in operational strategy.

Wastewater Engineers & Consultants

Support the design of new facilities and upgrades of existing ones. Identify actions for optimisation and improved operational efficiency.


Evaluate a large number of alternatives within a reasonable time frame. Develop and implement custom process models and automate objective evaluation and advanced statistical analysis.

No in-house modellers?

Let’s work together on a customised solution to fit your unique process configuration and objective

Get inspired by how WEST has improved these WWTPs

"We chose WEST for its great capabilities in describing biological processes in wastewater treatment systems and its high potential for customisation through the creation of new process models and process units that are not present in the standard library. Furthermore, the intuitive graphical user interface and the ease of importing our own data allowed us to rapidly build complex plant layouts, such as the one of Ravenna WWTP (240,000 PE)."

- Ida Basta, Process Engineer, HERA S.p.A.

Featured software subscription package

Wastewater Treatment

Develop digital twins, implement new control strategies and optimise plant operations using the open and flexible software platform, WEST+, for advanced process modelling and statistical analyses.

Additional capabilities & unique features

Are you interested in using WEST but have little experience in process modelling? You can start by using WEST Basic, our new entry-level product to construct and simulate simple plant layouts.

When studying novel treatment approaches, software tools are required to be both sufficiently flexible to capture newly acquired knowledge, such as models and data, and fast enough to evaluate a large number of alternatives within a reasonable timeframe. WEST excels in both areas, as demonstrated by its Block Editor and Model Editor applications (for developing custom model libraries) and the availability of the WEST engine on a number of high performance computing (HPC) infrastructures and supercomputers.

Modelling of WWTP process dynamics (in view of optimal control design) requires high-frequency input time series, which may not always be available from on-site measurements. With WEST, you can define the time series for influent quantity and quality based on essential information in the served catchment and several pre-defined discharge patterns.

Determine energy balances and costs to identify pitfalls and inefficiencies in WWTP operations and assess optimisation potential. Support decision-making to increase efficiency and reduce energy footprint in specific process units and at plant-wide level using WEST’s detailed energy and cost calculations.

Create a digital twin of your WWTP to predict the dynamic response to variations such as the influent water quantity and quality. Identify sensor drift and equipment anomalies using DHI’s online data validation tools along with WEST models to identify and track long-term shifts in plant loadings and microbial populations. Use calibrated WEST models to train operators and test alternative operational scenarios in an offline simulation environment. Understand the integrated nature of WWTP processes using custom dashboards, graphical outputs, defined control handles and the Advanced Experiments (such as Scenario Analysis) tools.

Access detailed models for centrifugal and positive displacement pumps and blowers in the latest block library, along with control models for different configurations of multiple pumps and blowers in parallel.

Novel biological processes are being developed to enhance carbon capture, rather than mineralization, by microorganisms in order to increase energy recovery in downstream processes. With WEST, you can describe these processes that can be seamlessly interfaced with other process unit models.

The excess sludge of a wastewater treatment plant contains valuable resources (material and energy) that can be harvested, thereby reducing the overall cost of operating a facility. Use the anaerobic digestion, stripping, precipitation / crystallization and scrubbing unit process models to simulate a nutrient and energy recovery sludge treatment train.

Inorganics can represent a considerable fraction of suspended solids entering a WWTP and have a significant impact on the operation of mechanical equipment and sludge production. A novel process model is now present in WEST to provide a detailed description of the fate of ISS throughout the different units of a WWTP, eventually allowing for a more precise quantification of sludge handling and disposal costs.

A number of tertiary treatment units, such as sand filtration, chlorination and UV disinfection, are now available in the WEST block library.

Simulate water quality in sewers, a WWTP and water recipients (such as rivers) using the integrated urban water systems (IUWS) model library. Identify synergies, determine and minimise impacts on downstream environments and globally optimise wastewater system performance.

Take advantage of the dedicated add-on with models of OSMART® control logic. OSMART® is an algorithm developed by E.T.C Sustainable Solutions (Trento, Italy) to control intermittent aeration in activated sludge processes. It features several economical and environmental benefits in the operation of a wastewater treatment plant.Read more about OSMART here.

Model calibration is an essential part of the model development process. With WEST, you can identify operational parameters that influence plant performance using the Local and Global Sensitivity Analysis. In addition, WEST allows you to efficiently calibrate your model using the dedicated Parameter Estimation tool. Evaluate WWTP response under uncertain and variable boundary conditions and biokinetics using the Uncertainty Analysis and Scenario Analysis tools.

WEST makes it easy to access all of your project information in one place. All relevant information present in a WEST project (plant layout, user’s notes, graphical output) can be gathered in a single document through the rich text notes and automated report generation feature.

The latest release of WEST is shipped with two model libraries: the traditional MSL library and a brand new Modelica library. Modelica is a modeling language with better features and much more widely used than MSL. The Modelica library will gradually replace the MSL library, which will not be further developed.

A variety of APIs is available on top of the WEST back-end, called Tornado, the most comprehensive being the .Net API. Other APIs include, C++, JAVA/JNI, OpenMI, MATLAB/MEX, etc.

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