.. _systems: Systems & Publications ====================== ``QSDsan`` is built upon the quantitative sustainable design (QSD) methodology, which provides a structured approach to prioritize the research, development, and deployment of early-stage technologies. Leveraging the QSD methodology, ``QSDsan`` powers a growing library of systems for wastewater treatment, sanitation, and resource recovery technologies. This page introduces the foundation metholodologies and includes a non-exhaustive list of the published systems with links to their source code in ``EXPOsan`` and their publications. Platform and methodology ------------------------- .. grid:: 1 :gutter: 4 .. grid-item-card:: Structured methodology: (QSD) .. image:: ../images/systems/qsd.png :width: 400px :align: left Research, development, and deployment (RD&D) of innovative technologies are often impeded by the lack of transparent, systematic, and agile approaches to prioritize investment across the expansive landscape of technologies and design/operational decisions. This tutorial review synthesizes research on sustainability analyses to present Quantitative Sustainable Design (QSD) – a structured methodology to expedite the RD&D of water, sanitation, and resource recovery technologies. *Li, Y.; Trimmer, J. T.; Hand, S.; Zhang, X.; Chambers, K. G.; Lohman, H. A. C.; Shi, R.; Byrne, D. M.; Cook, S. M.; Guest, J. S. Quantitative Sustainable Design (QSD): A Methodology for the Prioritization of Research, Development, and Deployment of Technologies. Environ. Sci.: Water Res. Technol. 2022, 8 (11), 2439–2465.* +++ .. button-link:: https://doi.org/10.1039/D2EW00431C :color: primary Read Paper .. grid-item-card:: Integrated platform: QSDsan .. image:: ../images/systems/qsdsan.png :width: 400px :align: left An open-source Python tool that integrates system design, simulation, and sustainability characterization (techno-economic analysis and life cycle assessment) to quickly identify critical barriers, prioritize research opportunities, and navigate multi-dimensional sustainability tradeoffs for technology RD&D. *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.* +++ .. button-link:: https://doi.org/10.1039/D2EW00455K :color: primary Read Paper .. grid-item-card:: Decision-making: DMsan .. image:: ../images/systems/dmsan.png :width: 400px :align: left A multi-criteria decision analysis package that integrates with ``QSDsan`` to compare alternatives across technical, resource-recovery, economic, environmental, and social criteria. *Lohman, H. A. C.; Morgan, V. L.; Li, Y.; Zhang, X.; Rowles, L. S.; Cook, S. M.; Guest, J. S. DMsan: A Multi-Criteria Decision Analysis Framework and Package to Characterize Contextualized Sustainability of Sanitation and Resource Recovery Technologies. ACS Environ. Au 2023, 3 (3), 179–192.* +++ .. button-link:: https://doi.org/10.1021/acsenvironau.2c00067 :color: primary Read Paper .. button-link:: https://github.com/QSD-Group/DMsan/ :color: secondary Source Code Water Resource Recovery Facilities ---------------------------------- 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, we validated the process modeling and dynamic simulation capacities of QSDsan through BSM1. BSM2 is also implemented in ``EXPOsan``. .. grid:: 1 :gutter: 3 .. grid-item-card:: Benchmark Simulation Model No. 1 (BSM1) Validated Python implementation of the `BSM1 system `_ by the International Water Association (IWA). +++ .. button-link:: https://doi.org/10.1039/D2EW00455K :color: primary Read Paper .. button-link:: https://github.com/QSD-Group/EXPOsan/tree/main/exposan/bsm1 :color: secondary Source Code .. grid-item-card:: Benchmark Simulation Model No. 2 (BSM2) Validated Python implementation of the IWA `BSM2 system `_. +++ .. button-link:: https://doi.org/10.1039/D2EW00455K :color: primary Read Paper .. button-link:: https://github.com/QSD-Group/EXPOsan/tree/main/exposan/bsm2 :color: secondary Source Code WERF Treatment Trains ********************* In Zhang et al., 2026, 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. These simulation models have been implemented in ``EXPOsan``. More details can be found in :ref:`the interactive page `. .. grid:: 1 :gutter: 3 .. grid-item-card:: WERF Treatment Trains *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.* +++ .. button-ref:: wrrf_interactive :ref-type: ref :color: primary Interactive Page .. button-link:: https://doi.org/10.1038/s41545-025-00537-4 :color: primary Read Paper .. button-link:: https://github.com/QSD-Group/EXPOsan/tree/main/exposan/werf :color: secondary Source Code Other WRRFs *********** .. grid:: 1 :gutter: 3 .. grid-item-card:: Anaerobic Digestion Model No. 1 (ADM1) Validated Python implementation of IWA `ADM1 `_. +++ .. button-link:: https://github.com/QSD-Group/EXPOsan/tree/main/exposan/adm :color: secondary Source Code .. grid-item-card:: Activated Sludge Models (ASMs) Validated Python implementation of IWA `ASM `_. +++ .. button-link:: https://github.com/QSD-Group/EXPOsan/tree/main/exposan/asm :color: secondary Source Code .. grid-item-card:: Conventional Activated Sludge Python implementation of the CAS system as described in `Shoerner et al. `_ +++ .. button-link:: https://github.com/QSD-Group/EXPOsan/tree/main/exposan/cas :color: secondary Source Code .. button-link:: https://github.com/QSD-Group/AnMBR :color: secondary Source Code | MATLAB .. grid-item-card:: Modular Encapsulated Two-stage Anaerobic Biological system (METAB) *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.* +++ .. button-link:: https://doi.org/10.1021/acs.est.4c05389 :color: primary Read Paper .. button-link:: https://github.com/QSD-Group/EXPOsan/tree/main/exposan/metab :color: secondary Source Code .. grid-item-card:: EcoRecover *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.* +++ .. button-link:: https://doi.org/10.1038/s41545-025-00545-4 :color: primary Read Paper .. button-link:: https://github.com/QSD-Group/EXPOsan/tree/main/exposan/pm2_batch :color: secondary Source Code | Batch .. button-link:: https://github.com/QSD-Group/EXPOsan/tree/main/exposan/pm2_ecorecover :color: secondary Source Code | EcoRecover ---------- Non-sewered sanitation systems (NSSSs) -------------------------------------- .. grid:: 1 :gutter: 3 .. grid-item-card:: NSS typologies across 77 countries *Lohman, H. A. C.; Li, Y.; Zhang, X.; Morgan, V. L.; Watabe, S.; Rowles, L. S.; Cusick, R. D.; Guest, J. S. Defining Economic and Environmental Typologies across 77 Countries to Prioritize Opportunities for Nonsewered Sanitation. Environ. Sci. Technol. 2025, 59 (29), 15101–15114.* +++ .. button-link:: https://doi.org/10.1021/acs.est.5c02064 :color: primary Read Paper .. grid-item-card:: Biogenic Refinery *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.* +++ .. button-link:: https://doi.org/10.1021/acsenvironau.2c00022 :color: primary Read Paper .. button-link:: https://github.com/QSD-Group/EXPOsan/tree/main/exposan/biogenic_refinery :color: secondary Source Code .. grid-item-card:: Bwaise *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.* +++ .. button-link:: https://doi.org/10.1021/acs.est.0c03296 :color: primary Read Paper .. button-link:: https://github.com/QSD-Group/EXPOsan/tree/main/exposan/bwaise :color: secondary Source Code .. button-link:: https://github.com/QSD-Group/Bwaise-sanitation-alternatives :color: secondary Source Code | Original .. grid-item-card:: Eco-San Based on the Eco-San system developed by Yixing Eco-sanitary Manufacture Co., Ltd. +++ .. button-link:: https://github.com/QSD-Group/EXPOsan/tree/main/exposan/eco_san :color: secondary Source Code .. grid-item-card:: NEWgenerator *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.* Note: the NEWgenerator system is under non-disclosure agreement (NDA), thus unit design is not publicly available, but the system design is implemented in ``EXPOsan``. +++ .. button-link:: https://doi.org/10.1021/acsenvironau.3c00001 :color: primary Read Paper .. button-link:: https://github.com/QSD-Group/EXPOsan/tree/main/exposan/new_generator :color: secondary Source Code .. grid-item-card:: Reclaimer Based on the work described in `Trotochaud et al. `_ for the Reclaimer 2.0 system designed by researchers at Duke University. +++ .. button-link:: https://github.com/QSD-Group/EXPOsan/tree/main/exposan/reclaimer :color: secondary Source Code ---------- Other Systems ------------- .. grid:: 1 :gutter: 3 .. grid-item-card:: Hydrothermal systems for biobinder and biofuels from food waste *Ahmad, A.; Kawale, H. D.; Summers, S.; Bogarin Cantero, B. C.; Allen, C. M.; Hajj, R. M.; Davidson, P. C.; Zhang, Y.; Li, Y. Financial Viability and Carbon Intensity of Hydrothermal Waste Valorization Systems for Bio-Based Asphalt Binder. Chemical Engineering Journal 2026, 528, 172283.* +++ .. button-link:: https://doi.org/10.1016/j.cej.2025.172283 :color: primary Read Paper .. button-link:: https://github.com/QSD-Group/EXPOsan/tree/main/exposan/biobinder :color: secondary Source Code .. grid-item-card:: Hydroxyapatite (HAp) Synthesis from Urine *Müller, I. E.; Lin, A. Y. W.; Otani, Y.; Zhang, X.; Wu, Z.-Y.; Kisailus, D.; Mouncey, N. J.; Guest, J. S.; Rad, B.; Ercius, P.; Yoshikuni, Y. Cost-Effective Urine Recycling Enabled by a Synthetic Osteoyeast Platform for Production of Hydroxyapatite. Nat Commun 2025, 16 (1), 4216.* +++ .. button-link:: https://doi.org/10.1038/s41467-025-59416-8 :color: primary Read Paper .. button-link:: https://github.com/QSD-Group/EXPOsan/tree/main/exposan/hap :color: secondary Source Code .. grid-item-card:: Hydrothermal systems for fuel and fertilizer production from wet organic wastes *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.* +++ .. button-link:: https://doi.org/10.1021/acs.est.5c07190 :color: primary Read Paper .. button-link:: https://github.com/QSD-Group/EXPOsan/tree/main/exposan/htl :color: secondary Source Code .. grid-item-card:: Point-of-use disinfection technologies *Elijah, B. C.; Ahmad, A.; Li, Y.; Plazas-Tuttle, J.; Rowles, L. S. Assessing the Relative Sustainability of Point-of-Use Water Disinfection Technologies for Off-Grid Communities. ACS Environ. Au 2024, 4 (5), 248–259.* +++ .. button-link:: https://doi.org/10.1021/acsenvironau.4c00017 :color: primary Read Paper .. button-link:: https://github.com/QSD-Group/EXPOsan/tree/main/exposan/pou_disinfection :color: secondary Source Code .. grid-item-card:: Hydrothermal systems for sustainable aviation fuel from food waste *Si, B.; Wang, Z.; Watson, J.; Summers, S.; Li, Y.; Yu, S.; Yang, H.; Yang, Z.; Heyne, J. S.; Jiang, J.; Ren, Z. J.; Ma, H.; Wang, C.; Wang, P.; Zhang, Y. A Circular Hydrothermal Refinery for Sustainable Aviation Fuel from Food Waste. Nat Sustain 2026, 1–11.* +++ .. button-link:: https://doi.org/10.1038/s41893-026-01848-1 :color: primary Read Paper .. button-link:: https://github.com/QSD-Group/EXPOsan/tree/main/exposan/saf :color: secondary Source Code ---------- Additional Publications ----------------------- Papers published by external users. #. `Advancing the Economic and Environmental Sustainability of Rare Earth Element Recovery from Phosphogypsum `_ #. `N2O as reactant rather than pollutant at wastewater treatment plants: Life Cycle Assessment and Techno-Economic Analysis of N2O-to-phenol `_ #. `Cost and Carbon Implications of Industrial Organic Load Reduction across Water Resource Recovery Facility Typologies `_ .. toctree:: :hidden: wrrf_interactive