# Wastewater treatment parameters extraction methodology

## Sources
- **HydroWASTE** – `datasets/waste_water/hydrowaste_nigeria_subset.csv` and `.json`, derived from HydroWASTE v10 (https://www.hydrosheds.org/products/hydrowaste).
- **Oke-Afa WWTP** – `docs/waste_water/oke_afa_wwtp_lagos_2021.md` / Zenodo DOI https://doi.org/10.5281/zenodo.10426207.
- **NIR1 domestic wastewater** – `docs/regulatory_mrv/11_Nigeria_NIR1_2000_2017.md`, Section 7.3.2 / Tables 7.4–7.5.

## Transformations
- HydroWASTE `WASTE_DIS` was used as the daily flow / capacity proxy because `DESIGN_CAP` is empty in the Nigeria subset.
- Oke-Afa population served is >50,000 from the study-area text; capacity is inferred from "over four million litres" of wastewater generated daily.
- NIR1 aggregate row records total organic wastewater (TOW) and population for 2017; a daily BOD concentration is not supplied in the source.

## Validation
- Three Nigerian WWTP records were extracted from HydroWASTE.
- Oke-Afa influent BOD mean (127.5 mg/L) was cross-checked against Table 1.