April 2026 monthly work summary focusing on strengthening developer workflow, packaging, and data handling reliability for QSDsan. Key outcomes include streamlined testing/documentation/issue reporting workflows, stabilized data handling across pandas/numpy versions, and groundwork for smoother future upgrades and maintenance.

September 2025 monthly summary for QSD-Group/EXPOsan focusing on business value, reliability, and maintainability. Key features delivered: - GPS-X plotting improvements: achieved plotting consistency by aligning secondary y-axis ticks with the primary axis and refining chart visuals to better communicate results. - WERF core data/config updates: introduced a develop-oriented config (werf.yml), updated core data files, refined loading behavior, and expanded tests and usage examples to improve reliability and user workflow. - Codebase reorganization: clarified project structure for werf-related files, updated imports, and adjusted test ignore rules to streamline development. - GPS-X results data update: refreshed the GPS-X results dataset (binary file) to reflect the latest analyses used in ongoing work. Major bugs fixed: - Minor bug fixes across the WERF workflow and test suite, including test_werf.py adjustments and related data/config handling to improve stability and consistency of runs. Overall impact and accomplishments: - Improved data visualization reliability and interpretability, enabling faster, more accurate decision-making for analyses that rely on GPS-X visuals. - Increased reproducibility and reliability of WERF-based workflows through better config management, tests, and loading behavior. - Enhanced code maintainability and onboarding through file reorganization and clearer imports, reducing future maintenance costs. - Strengthened data pipeline with up-to-date GPS-X results, reducing drift between analyses and reported outputs. Technologies/skills demonstrated: - Python scripting and plotting (data visualization and script maintenance) - Data/config management and test automation - Codebase refactoring, project organization, and test strategy - Data handling and binary dataset maintenance

August 2025 monthly summary for QSDsan and EXPOsan focusing on high-value deliverables and reliability improvements across both models. Key features delivered: - MetalDosage unit enhancements in QSDsan: introduced colloidal_fraction parameter, updated default apparent pKsp values, adjusted coagulation assumptions, updated default fractionation, input validation fix in interpolation, and doctest updates to MetalDosage. - Added refresh_stoichiometry utility for ADM1p and mASM2d to refresh stoichiometric coefficients when component properties change, ensuring consistency in reaction calculations. - Unified defaults for wastewater treatment models in EXPOsan with EBPR tuning to improve reliability and cross-module performance. - WRRF performance visualization and reporting enhancements: new plotting capabilities to compare WRRF performance against GPS-X data. - Baseline simulations updates and plotting adjustments to support analysis and reporting, including reruns and small cleanup efforts. Major bugs fixed: - ADM/ASM component attribute synchronization: corrected the direction of synchronization in A1junction so ADM components update to match ASM where discrepancies exist. - Autotroph washout issue in I3.py: adjusted anaerobic volume parameters to stabilize nitrification performance. Overall impact and accomplishments: - Improved data consistency and integrity across QSDsan and EXPOsan, reducing drift between ADM and ASM models and stabilizing nitrification performance. - Increased reliability of default configurations and EBPR tuning, leading to more predictable model behavior in demonstrations and reporting. - Enhanced decision-support capabilities through new visualization features and streamlined baseline analyses, enabling faster, more informed planning. Technologies/skills demonstrated: - Python-based modeling, parameter management, and utility development (stoichiometry refresh). - Input validation, doctest maintenance, and cross-model synchronization. - Data visualization and reporting enhancements, with alignment to external data references (GPS-X). - Baseline simulation orchestration and plotting/export workflow improvements. Business value: - More reliable and auditable models, with consistent defaults across modules, leading to faster onboarding, clearer reports for stakeholders, and improved confidence in decision-making.

July 2025 monthly summary focused on delivering uncertainty-aware process models, enhanced economic analyses, and API/documentation improvements across the QSDsan project portfolio. The work strengthened decision-support capabilities, improved cost visibility for wastewater operations, and prepared the codebase for broader integration with BSM2 workflows and downstream tooling.

June 2025 monthly summary for QSD Group development work, focusing on delivering robust, production-ready features, improving documentation, and strengthening the reliability of energy and aeration models across EXPOsan and QSDsan repositories.

May 2025 monthly summary for QSD-Group/EXPOsan focused on delivering cost-aware simulation optimizations for wastewater treatment operations, centralizing critical data assets, and enhancing optimization workflows. The work emphasizes business value through OPEX reduction, more robust analyses, and faster, cache-friendly simulations.

April 2025: Delivered notable advancements in stability, cost visibility, and analytics across EXPOsan and QSDsan. Core achievements include stabilization of core wastewater model convergence and PAO kinetics standardization; cross-config MMP kinetics in aerobic digesters; nutrient recovery and ECS analysis enhancements; expanded OPEX metrics and robust baseline simulations; and targeted improvements to analysis tooling and reporting. Also fixed key bugs affecting Excel writer mode and TS% loops. These contributions improve prediction reliability, drive cost-aware optimization, and strengthen business case for treatment configurations.

March 2025 performance summary for QSD-Group development efforts across EXPOsan and QSDsan. The month focused on delivering high-impact features, stabilizing simulations, and tightening cross-repo consistency to accelerate scenario testing and decision-making.

February 2025 monthly summary: Delivered substantial modeling enhancements across EXPOsan and QSDsan, strengthening predictive accuracy, operational insights, and deployment reliability. Major features include ASM2d-based wastewater modeling with urine/feces production and urine stream separation (EX unit) with population-equivalent scaling, nitrogen and phosphorus mass tracking, and downstream integration. Implemented an aeration demand estimation helper with OTR caching for reuse by MBR/CSTR/PFR units, enabling faster and more consistent aeration analyses. Refined initial flowrates calculation for suspended growth bioreactor to account for influent fractions and internal recycle, improving model initialization. Introduced Mbamba and Musvoto kinetic alternatives and updated constants, supporting better chemical equilibrium calculations and model flexibility across ADM1p and mASM2d. Documentation updates for BSM2 and WRRF configurations, plus default K_PP parameter correction in ADM1_p_extension/ADM1p. Also performed CI/CD cleanup (removal of outdated build-dev.yml) and doctest/test value corrections to align with latest parameterizations, reinforcing reliability and test fidelity. These changes collectively enhance accuracy, reduce design risk, and enable more reliable optimization and scale-up decisions.

January 2025 performance highlights across QSD-Group/EXPOsan and QSD-Group/QSDsan. The month delivered tangible business value by tightening data integrity, stabilizing tests, and enhancing reproducibility in analytical workflows. Key outcomes include improved accuracy of bioprocess cost data, unit consistency, and elemental flow calculations; stabilized and aligned test suites for refinery/reclaimer models; enhanced visualization capabilities with reproducibility seeds for consistent analyses; optional molecular-weight adjustments with clarified MW-based calculations and updated documentation; and doctest/documentation alignment for components and PFR examples to improve reliability and onboarding.

December 2024 performance summary for QSDsan and EXPOsan: Key deliverables across repositories: - ADM1p H2 solver improvement in QSDsan: corrected inhibitory effects calculation, added substrate inhibition parameter (S_IP), refined warnings for dissolved H2/CH4 being ignored, and ensured hydrogen concentration handling uses solve_pH when pH is not provided. - MetalDosage unit introduced in QSDsan with mass-balance calculations and integration into chemical/stream handling, enabling more accurate modeling of coagulation and precipitation processes. - Precipitation solver robustness enhanced: fallback from the initial bisection method to the aitken_secant method when needed for improved reliability. - Numerical stability safeguards implemented in QSDsan: prevention of negative state values and refinement of small thresholds to zero out negligible updates. - IdealClarifier input size handling corrected: _ins_size_is_fixed changed from True to False to improve stream sizing behavior. - EXPOsan CI/CD and dependency hygiene improved: update build-dev workflow to align with the correct EXPOsan branch (werf) and remove outdated bsm2 branch reference. - Broad code quality and maintenance activities: checkpoint milestones, H1 and general code cleanup/refactoring, and README/documentation updates to improve readability and reproducibility. Overall impact: - More reliable, accurate and maintainable process simulations with clearer diagnostics and safer defaults, enabling faster iteration and stronger business decisions. Technologies and skills demonstrated: - Python-based numerical solvers, pH-aware hydrogen handling, mass-balance modeling, unit design, solver fallbacks, and CI/CD workflow maintenance; code cleanup and documentation practices to improve long-term sustainability.

November 2024: Expanded modeling capabilities across EXPOsan and QSDsan with new process models, unit operations, and add-ons; improved documentation, initialization exports, and data robustness; enhanced testing and doctests to ensure maintainability and reliability. These changes deliver higher-fidelity wastewater simulations, streamlined model construction, and more robust data handling, enabling faster decision-making and more accurate performance predictions.

Month 2024-10: Improved scholarly citation accuracy and documentation quality across two critical repositories. Delivered DOI-based citations for a research paper in EXPOsan and updated Systems.rst with a specific DOI and author attribution in QSDsan, enhancing discoverability and proper attribution. No runtime features or bug fixes were deployed this month; the work strengthens documentation standards, traceability, and reproducibility for researchers and contributors.