Sample data
Loaded monitoring results become the period averages and removal efficiencies below, computed once under the stated conventions — not typed in by hand, and not left for you to work out per pollutant.
Results loaded
184
sampling window 2025-Q1 to Q4
Pollutants with usable pairs
15/17
silver mostly ND · thallium has none
Non-detects
33
substituted at ½ detection limit
Worst mass-balance closure
61%
mercury — two fifths unaccounted for
| Pollutant | Influent avg | Effluent avg | n | Non-detects | Removal | Data quality |
|---|---|---|---|---|---|---|
| AntimonySb | 0.0051 | 0.00306 | 12 | 2 | 40% | — |
| Arsenic (total)As | 0.0051 | 0.00255 | 12 | 0 | 50% | — |
| AluminumAl | 0.055 | 0.00825 | 12 | 0 | 85% | — |
| CadmiumCd | 0.0051 | 0.001275 | 12 | 1 | 75% | — |
| Chromium (VI)Cr6 | 0.0017 | 0.00085 | 12 | 4 | 50% | — |
| Chromium (total)Cr | 0.085 | 0.017 | 12 | 0 | 80% | — |
| CopperCu | 0.1037 | 0.015555 | 12 | 0 | 85% | — |
| CyanideCN | 0.0697 | 0.02788 | 12 | 3 | 60% | — |
| LeadPb | 0.0833 | 0.01666 | 12 | 1 | 80% | — |
| MercuryHg | 0.00051 | 0.000179 | 12 | 2 | 65% | — |
| MolybdenumMo | 0.017 | 0.0119 | 8 | 0 | 30% | — |
| NickelNi | 0.0357 | 0.019635 | 12 | 0 | 45% | — |
| SeleniumSe | 0.0017 | 0.001105 | 12 | 5 | 35% | — |
| SilverAg | 0.0085J | 0.002125J | 12 | 9 | ref 75% | 3 of 12 above detection
reference removal used |
| ThalliumTl | no data | — | — | — | ref 40% | Insufficient data
human-health criterion + ref removal — provisional |
| TributyltinTBT | 0.00042J | 0.000126J | 8 | 6 | ref 70% | 2 of 8 above detection
reference removal used |
| ZincZn | 0.2975 | 0.0595 | 12 | 0 | 80% | — |
Non-detects substituted at ½ the detection limit —
applied to 33 results.
J estimated — result between the detection and quantitation limits.
Removal shown as ref where site data cannot support an observed rate.
Mass balance
Influent load vs effluent + biosolids
Influent load compared against effluent plus biosolids. Closure far from 100% means a sampling problem, not a treatment result.
Copper
97%
Zinc
94%
Lead
128%
Mercury
61%
Mercury closes at 61%.
Roughly two fifths of the influent load is unaccounted for. Most often this is biosolids
sampling timing rather than real loss — worth resolving before you rely on the mercury limit.
Conventions in force
Every derived value above assumes these — stated once, applied everywhere
AVG
Arithmetic mean of the period
Not a geometric mean. Metals loadings are additive.
ND
Substitute ½ detection limit
Applied to 33 results. State this in the
submittal — reviewers check it.
MIN
8 pairs for an observed removal rate
Below that the study falls back to a reference rate automatically.
REF
Reference removals from EPA 2004 guidance
In use for silver 75%, tributyltin
70%, thallium 40% ·
EPA 833-R-04-002A
OUT
Outliers retained
Nothing is dropped silently. Exclusions require a written reason.