Water Reclamation Efficiency
VC-MET-307 — the fraction of delivered irrigation water recovered, treated, and returned to the closed loop, the headline conservation measure for the facility water economy.
Definition
Water Reclamation Efficiency (WRE) is the percentage of irrigation water delivered to cultivation zones that is subsequently recovered, treated to specification, and returned to the closed hydro-loop within the accounting hour. The complement — water lost to transpiration carried out of capture, drift, drain-to-waste, and reject from treatment — is the make-up the facility must draw from reserve. WRE is the core figure in the water mass-balance and the basis for every conservation commitment Sector-7 holds.
Why it matters
Sector-7 runs on a closed water economy with finite reserve; a slip in reclamation translates directly into make-up draw and shortens the runway before reserve constraints bite. A declining WRE is also an early sign of treatment-train fouling, membrane degradation, or a capture leak long before any tank-level alarm fires. CHLORA computes the hourly mass balance, trends make-up demand, and presents WRE on the Operations Dashboard as a sustainability and cost-control headline.
Formula
WRE is an hourly mass balance of recovered versus delivered water:
WRE = 100 · ( V_returned / V_delivered )
over trailing 60 min, volumetric
where:
V_delivered = metered volume sent to cultivation zones
V_returned = volume recovered AND treated to spec AND
returned to the loop (untreated capture excluded)
Loss accounting (complement, published alongside):
V_loss = V_delivered − V_returned
= V_transpired + V_drift + V_drain + V_reject
Closure check:
V_makeup (metered reserve draw) must reconcile with V_loss
within ± 1.5%; larger gap → flag MASS_BALANCE_OPEN (leak or
meter fault) and hold WRE with a confidence flag.
Treated-to-spec gate: returned water failing conductivity or
turbidity limits is counted as reject, not return. Inputs
| Channel | Role | Cadence | Reference | Source |
|---|---|---|---|---|
| Delivery flow meter | V_delivered to zones | 1 min → hourly sum | L, ± 0.5% | PhytoSense Mesh |
| Return flow meter | V_returned to loop | 1 min → hourly sum | L, ± 0.5% | PhytoSense Mesh |
| Treatment quality | To-spec gate (EC, turbidity) | 5 min | Conductivity / NTU limits | PhytoSense Mesh |
| Make-up meter | Reserve draw closure check | 1 min → hourly sum | L, ± 0.5% | CHLORA |
Units & Scale
WRE is a percentage on a 0–100 scale, reported to one decimal place from an hourly volumetric mass balance. It is not instantaneous — it integrates flows over the accounting hour to smooth irrigation-cycle pulses. Facility WRE is the volume-weighted figure across treatment trains, not a train average. A MASS_BALANCE_OPEN flag degrades confidence when make-up draw fails to reconcile with computed loss within ± 1.5%.
Sampling & Source
- Computed every 1 hour by CHLORA as a volumetric mass balance over the trailing 60 minutes.
- Delivery, return, and make-up volumes metered on the PhytoSense Mesh at 1-min resolution and summed hourly.
- Only water treated to conductivity and turbidity spec counts toward V_returned; off-spec is reject.
- Stale handling: meter dropout → hour marked partial and DEGRADED; closure gap > 1.5% → MASS_BALANCE_OPEN.
Thresholds
OK
Closed-loop conservation on target. No action.
WARN
Make-up draw rising; inspect treatment train and capture.
CRIT
Major loss; reserve runway shortening fast.
Recent Trend
Facility water reclamation efficiency in percent, last 14 hourly balances:
Interpretation Guidance
| WRE Band | Reading | Likely Driver | Action |
|---|---|---|---|
| 97–99% | Excellent | Treatment train healthy, low loss | None; log as reference. |
| 92–96.9% | Nominal | Normal transpiration loss | None; normal operating band. |
| 88–91.9% | Slipping | Early fouling or rising reject | Inspect membranes; check return quality. |
| 80–87.9% | WARN lossy | Capture leak or train degradation | Trace mass balance; service treatment train. |
| < 80% | CRIT failing | Major leak or treatment failure | Invoke water-loss SOP; protect reserve runway. |
Related Metrics
Hydro-Loop Pressure
Shared hydro subsystem.
VC-MET-308Energy per Specimen
Treatment pumping is an energy load.
VC-MET-309Nutrient Dosing Rate
Returned water carries residual nutrient.
VC-MET-310Substrate Stock Coverage
Reserve consumables runway analogue.
VC-MET-301Dispatch Queue Depth
Leaks raise inspection tickets.
VC-MET-001Canopy Vitality Index
Water security underpins collection health.
Related SOPs
- SOP Library — water mass-balance, leak-trace, and treatment-service procedures.
- Leak isolation & reserve protection on WARN/CRIT — see the SOP Library.
- Mass-balance closure monitoring & meter-fault alerts — Monitoring Systems.