OVERVIEW
GBMSD's laboratory analyzes wastewater and solid samples for our customers using state-of-the-art equipment and following approved methodology.  Data generated from GBMSD's laboratory is used to monitor the treatment plant's effectiveness, generate bills to our customers, ensure compliance with our Sewer Use Ordinance and evaluate the environmental health of the Fox River and lower Green Bay.

CERTIFICATION
The GBMSD laboratory is certified by the State of Wisconsin and follows all guidelines set forth in the Wisconsin Laboratory Certification & Registration Program (NR 149). The laboratory is certified in the following test categories:

Oxygen Utilization

• Biochemical Oxygen Demand
• Carbonaceous Biochemical Oxygen Demand

Nitrogen

• Ammonia as Nitrogen
• Nitrate+Nitrate as Nitrogen
• Nitrite as Nitrogen
• Total Kjeldahl Nitrogen

Phosphorus

• Orthophosphorus
• Total Phosphorus

Physical

• Total Solids
• Total Suspended Solids

General I

• Chlorophyll a
• Hardness

General II

• Chemical Oxygen Demand
• Chloride
• Cyanide

Metals I

Silver, Aluminum, Arsenic, Barium, Beryllium, Calcium, Cadmium, Chromium, Copper, Iron, Mercury, Potassium, Magnesium, Manganese, Molybdenum, Sodium, Nickel, Lead, Antimony, Selenium, Thallium, Zinc.

Low Level Mercury

Organics, Purgeable

Organics, Organochlorine Compounds
PCB
Pesticides

Other:

• pH
• Fecal Coliform
• Residual Chlorine

Click here to link to the Laboratory Certification Home Page.

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	Weekly avg	26 mg/L	Daily	November-Dec
Ammonia Nitrogen	Weekly avg	15.0 mg/L	Daily	Jan-April
Ammonia Nitrogen	Weekly avg	4.7 mg/L	Daily	May-Sept
Ammonia Nitrogen	Weekly 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.