PERMIT
The Green Bay Metropolitan Sewerage District is allowed to discharge treated wastewater to the Fox River under the guidance and conditions of our Wisconsin Pollutant Discharge Elimination System (WPDES) permit. This permit, renewable every five years, sets the conditions and requirements that determine the degree of treatment we must provide in order to comply with the regulations of the State. The permit includes: effluent limits for parameters of concern; monitoring requirements for all influent and effluent streams; sludge processing requirements; reporting requirement; system operating requirements; and Pretreatment Program requirements. If the DNR determines that our existing plant is unable to meet existing conditions, or if they determine that new, stricter limits are necessary, the permit will also include a compliance plan, which stipulates a time period for new construction necessary to comply with these limits.
During the permit renewal process, the DNR closely evaluates historical effluent data, to assess compliance with existing limits and to determine the need to include new or revised limits in the subsequent permit. Current State Codes include criteria for hundreds of compounds, which, if detected in our effluent, could be controlled by a permit limit. Our current permit, which expires 9/30/10, contains relatively few permit limits, due to the low number of compounds of concern detected in our effluent.
Summary of WPDES Permit Limits for GBMSD Effluent
| Parameter |
Limit Type |
Limit and Units |
SampleFrequency |
Notes |
| Flow Rate |
|
MGD |
Daily |
|
| CBOD5 |
Monthly avg |
25 mg/L |
Daily |
Also Waste Load Allocation May-October |
| CBOD5 |
Weekly avg |
40 mg/L |
Daily |
|
| Total Suspended Solids |
Monthly avg |
30 mg/L |
Daily |
|
| Total Suspended Solids |
Weekly avg |
45 mg/L |
Daily |
|
| pH |
Range |
6.0 – 9.0 su |
Daily |
|
| Total Phosphorus |
Monthly avg |
1.0 mg/L |
Daily |
|
| Fecal Coliform |
Geometric mean |
400 #/100ml |
Weekly |
May-October |
| Total Residual Chlorine |
Daily max |
38µg/L |
Daily |
May-September |
| Ammonia Nitrogen |
Monthly avg |
26 mg/L |
Daily |
November-Dec |
| Ammonia Nitrogen |
Monthly avg |
15.0 mg/L |
Daily |
Jan-April |
| Ammonia Nitrogen |
Monthly avg |
4.7 mg/L |
Daily |
May-Sept |
| Ammonia Nitrogen |
Monthly avg |
14.0 mg/L |
Daily |
October |
Other permit conditions include monitoring requirements for seven heavy metals and total PCBs (monthly), acute and chronic Whole Effluent Toxicity tests (once per year in rotating quarters) and mass limits for Total Residual Chlorine.
