Effluent quality
Treatment efficiency over time
Per-sample-day percent removal for BOD5 and suspended solids: (influent − effluent) / influent. Sample days are roughly weekly; gaps are normal. The dashed red line marks 85% removal — a typical secondary-treatment performance floor; the actual SPDES permit floor is still TBD until the BOD5/SS limits are pulled in.
Effluent pH against permit envelope
Daily minimum (solid) and maximum (dashed) effluent pH for each plant. Green band marks the SPDES permit envelope (pH 6.0–9.0); red dashed lines mark the limits. Per-day values that touch or cross either limit indicate a potential reportable excursion.
Settleable solids against permit limit
Daily settleable-solids reading per plant. The 0.1 mL/L permit ceiling is shown as a dashed red line; the green band is the in-spec range. Below-detection readings (“<0.1”) are plotted at 0.05 mL/L (mid-point); the original reported string is shown in tooltips. Implausibly large readings traced to extractor errors against the March 2025 DMR (values > 5 mL/L) are dropped — these were a different mg/L column getting mis-mapped into settleable_solids.
Influent vs. effluent temperature
Daily influent (solid) and effluent (dashed) temperatures for each plant. Treatment is essentially passive thermally; this is a sanity-check view that confirms the data series tracks the seasonal cycle and that influent and effluent move together.
Sample-day removal — BOD5 and suspended solids
BOD5and suspended-solids samples are pulled on permit-defined sample days only (roughly weekly). Each point is one sampling event: x-axis is influent concentration, y-axis is the matched effluent concentration. The dashed diagonal is “no removal” (y = x); points well below the diagonal mean treatment is reducing the parameter.