Blueprint: Village Struvite Reactor (200 L Batch, 100-Person) — Build Specification

DESIGN BLUEPRINT — SIMULATED, NOT MEASURED — NOT BUILT. Build specification for the village struvite reactor designed in the source paper: Aldred, William Alexander, 'A Village Struvite Reactor Turning Source-Separated Urine into Fertiliser: Design and Phosphorus Budget for a 100-Person Community', DOI 10.5281/zenodo.24108844. The blueprint specifies the 200 L nominal batch reactor (140 L working volume) and 1,000 L storage tank with dimensions and fill depths, a bill of materials with quantities including the magnesium oxide charge of 0.142 kg per batch (51.9 kg per year), an assembly sequence, the daily operating cycle at pH 9.0 with a 2.0 h residence time, the operating envelope including the magnesium oxide price break-even of $1.23 per kg above which the design stops paying on fertiliser value alone, tolerances, failure modes and maintenance. All performance figures are taken from the source paper; derived quantities (vessel geometry, per-batch charges, packaging counts) are computed by the accompanying script compute.py and deposited as results.json. Calculated performance at the design point: 87.8% phosphorus recovery, 231.2 kg of struvite per year for 100 people at 28.9% P2O5.