Systems

This page documents the systems that have been/is being developed using QSDsan with links to the source codes in GitHub and publications.

Benchmark Simulation Models

The Modelling and Integrated Assessment (MIA) Specialist Group of the International Water Association has established benchmark simulation models (BSMs) to provide a consistent environment for wastewater treatment plant (WWTP)/water resource recovery facility (WRRF) evaluation (see BSM webpage and MATLAB implementation and report).

When publishing the paper that introduces QSDsan [1], we validated the process modeling and dynamic simulation capacities of QSDsan through BSM1 (bsm1 EXPOsan module, bsm1 archived codes). BSM2 is also implemented in EXPOsan.

Water Resource Recovery Facilities

In Zhang et al., 2026 [2], we developed 18 benchmark combinations of liquid and solid treatment trains, which cover over 70% of the total treatment capacity of publicly owned treatment works (POTWs) in the Contiguous United States. These configurations were based on the Water Environment Research Foundation (WERF, now a part of the Water Research Foundation, WRF), report on net-zero energy solutions for WRRFs [3].

These simulation models have been implemented in the werf EXPOsan module. More details can be found in the interactive page.

Distinguishing features of benchmark WRRF configurations. A WRRF configuration is referred to as a unique combination of a liquid code (a) and a solid code (b) as defined in [2]. Configurations followed by a star (*) are implemented in EXPOsan.

Non-sewered sanitation systems (NSSSs)

Biogenic Refinery

• Publication: Rowles et al., 2022 [4]

• biogenic_refinery EXPOsan module

• biogenic_refinery archived codes

Bwaise

• Publication: Trimmer et al., 2020 [5]

• bwaise EXPOsan module

• bwaise Trimmer et al archived codes; bwaise Li and Zhang et al archived codes

Eco-San

• eco_san EXPOsan module

NEWgenerator

• Publication: Watabe et al., 2023 [6]

• new_generator EXPOsan module

• new_generator archived codes

Reclaimer

• reclaimer EXPOsan module

SCG Zyclonic

• scg_zyclonic EXPOsan module

Other Systems

A variety of other sanitation and resource recovery systems have been developed using QSDsan, including:

1. Conventional activated sludge process

   • Publication: Shoener et al., 2016 [7]

   • cas EXPOsan module

   • cas archived codes

2. Hydrothermal systems for fuel and fertilizer production from wet organic wastes

   • Publication: Feng et al., 2024 [8]

   • htl EXPOsan module

3. Modular encapsulated two-stage anaerobic biological (METAB) system

   • Publication: Zhang et al., 2024 [9]

   • metab EXPOsan module

4. EcoRecover system: microalgae-based tertiary P recovery process

   • Publication: Kim et al., 2025 [10]

   • pm2_ecorecover EXPOsan module

[1]

Li, Y.; Zhang, X.; Morgan, V. L.; Lohman, H. A. C.; Rowles, L. S.; Mittal, S.; Kogler, A.; Cusick, R. D.; Tarpeh, W. A.; Guest, J. S. QSDsan: An Integrated Platform for Quantitative Sustainable Design of Sanitation and Resource Recovery Systems. Environ. Sci.: Water Res. Technol. 2022, 8 (10), 2289–2303. https://doi.org/10.1039/D2EW00455K.

[2] (1,2)

Zhang, X.; Rai, S.; Wang, Z.; Li, Y.; Guest, J. S. An Agile Benchmarking Framework for Wastewater Resource Recovery Technologies. npj Clean Water 2025, 9 (1), 4. https://doi.org/10.1038/s41545-025-00537-4.

[3]

Tarallo, S., Shaw, A., Kohl, P. & Eschborn, R. A Guide to Net-Zero Energy Solutions for Water Resource Recovery Facilities. https://iwaponline.com/ebooks/book/293/ (2015).

[4]

Rowles, L. S.; Morgan, V. L.; Li, Y.; Zhang, X.; Watabe, S.; Stephen, T.; Lohman, H. A. C.; DeSouza, D.; Hallowell, J.; Cusick, R. D.; Guest, J. S. Financial Viability and Environmental Sustainability of Fecal Sludge Treatment with Pyrolysis Omni Processors. ACS Environ. Au 2022, 2 (5), 455–466. https://doi.org/10.1021/acsenvironau.2c00022.

[5]

Trimmer, J. T.; Lohman, H. A. C.; Byrne, D. M.; Houser, S. A.; Jjuuko, F.; Katende, D.; Banadda, N.; Zerai, A.; Miller, D. C.; Guest, J. S. Navigating Multidimensional Social–Ecological System Trade-Offs across Sanitation Alternatives in an Urban Informal Settlement. Environ. Sci. Technol. 2020, 54 (19), 12641–12653. https://doi.org/10.1021/acs.est.0c03296.

[6]

Watabe, S.; Lohman, H. A. C.; Li, Y.; Morgan, V. L.; Rowles, L. S.; Stephen, T.; Shyu, H.-Y.; Bair, R. A.; Castro, C. J.; Cusick, R. D.; Yeh, D. H.; Guest, J. S. Advancing the Economic and Environmental Sustainability of the NEWgenerator Nonsewered Sanitation System. ACS Environ. Au 2023, 3 (4), 209–222. https://doi.org/10.1021/acsenvironau.3c00001.

[7]

Shoener, B. D.; Zhong, C.; Greiner, A. D.; Khunjar, W. O.; Hong, P.-Y.; Guest, J. S. Design of Anaerobic Membrane Bioreactors for the Valorization of Dilute Organic Carbon Waste Streams. Energy Environ. Sci. 2016, 9 (3), 1102–1112. https://doi.org/10.1039/C5EE03715H.

[8]

Feng, J.; Strathmann, T. J.; Guest, J. S. Hydrothermal-Based Wastewater Solids Management for Targeted Resource Recovery and Decarbonization in the Contiguous U.S. Environ. Sci. Technol. 2025. https://doi.org/10.1021/acs.est.5c07190.

[9]

Zhang, X.; Arnold, W. A.; Wright, N.; Novak, P. J.; Guest, J. S. Prioritization of Early-Stage Research and Development of a Hydrogel-Encapsulated Anaerobic Technology for Distributed Treatment of High Strength Organic Wastewater. Environ. Sci. Technol. 2024, 58 (44), 19651–19665. https://doi.org/10.1021/acs.est.4c05389.

[10]

Kim, G.-Y.; Molitor, H. R.; Zhang, X.; Li, Y.; Shoener, B. D.; Schramm, S. M.; Morgenroth, E.; Snowling, S. D.; Hartnett, E.; Bradley, I. M.; Pinto, A. J.; Guest, J. S. Development of an Open-Source Process Simulator for Microalgae-Based Tertiary Phosphorus Recovery. npj Clean Water 2025, 9 (1), 13. https://doi.org/10.1038/s41545-025-00545-4.