Unusual Discharge Requests (UDRs)

MSD's pretreatment program issues permits to discharges with ongoing (continuous) discharges.  Additionally, short term "one-time" discharges may be discharged to the sewer system through the UDR program.  This program is designed to allow MSD to have sufficient control over the type and characteristics of the wastewater being discharged and to ensure that contaminants are not allowed to enter the sewer system which could potentially cause problems at the treatment plant (such as upset conditions, pass through or violation of limits).  Through the UDR program, wastewater is discharged to an on-site sewer connection. Typical types of UDRs include Underground Storage Tank (UST) excavations, bad batches of product, car wash holding tanks and purge water from monitoring wells.   Below is a description of the general process that is followed by MSD when a request is called in.  This information should be useful to potential dischargers:

Initial Request

Companies which have a batch of wastewater that needs to be disposed of (but which is not covered by any other MSD discharge permit) may call into MSD and describe their request.  Calls should be directed to Gary Kohler at 540-6917.

Processing Of Requests

MSD has developed a UDR Review Committee which typically meets on a weekly basis to review the requests for discharge.  This committee is made up of representatives from the Regulatory Services (RS), the Morris Forman Water Quality Treatment Center Treatment Plant and the MSD Laboratory.  Requests will be reviewed and processed by MSD by the UDR Review Committee and as a result, guidance regarding parameters for analysis, discharge constraints, and/or approval/denial of UDRs will be generated.

Parameters For Analysis

Based on the description of the request to discharge, MSD will determine what parameters need to be analyzed.  This decision will typically be made at the weekly committee meeting. However, MSD attempts to facilitate the UDR process to meet customer needs.

Some specific information regarding sampling parameters for UST excavations (a common request) follows:

USTs: MSD requires as a minimum, wastewater from all USTs must be analyzed for the following parameters:

  • Benzene, Toluene, Ethyl Benzene, Xylene (BTEX)
  • Total Petroleum Hydrocarbon (TPH or Oil & Grease Hydrocarbon)
  • Petroleum Aromatic Hydrocarbon (PAH)
  • Total Lead
  • Closed Cup Flashpoint

Sample Collection

Typically, at least one representative sample must be collected of the wastewater that is proposed for discharge.  "Representative" means that the collected sample has the same characteristics as the rest of the wastewater.  It is imperative that correct sampling protocol, as defined by Standard Methods, 40 Code of Federal Regulations (CFR) 136 and SW 846, be followed for sample collection, sample container, holding times, sample storage, chain of custody procedures, etc.  Samples should be analyzed by a laboratory in accordance with 40 CFR 136 for the parameters as specified by MSD.  MSD reserves the right to require a portion of the representative sample if requested.  MSD may also require that RS personnel be present when the wastewater is sampled.  Requestors will be notified regarding UDR approval/denial based on the submittal information.