CSM Illicit Discharge Detection & Elimination (IDDE) 2

Question 1

During an IDDE field investigation, a field technician observes gray, sudsy water flowing from an outfall during dry weather. Which upstream source is MOST likely responsible?

Accepted Answer

A cross-connected laundry or washing machine drain

Answer

Gray, sudsy water during dry weather is a classic sign of laundry or household washing machine wastewater cross-connected to the storm drain, due to the presence of detergents and surfactants.

Question 2

What is the recommended approach for tracing an illicit discharge upstream once flow is confirmed at an outfall during dry weather?

Accepted Answer

Walk the contributing drainage area and systematically check manholes and inlets moving upstream

Answer

Systematic upstream manhole and inlet investigation — walking the system from the outfall — is the standard IDDE field methodology to isolate the source of an illicit discharge.

Question 3

Which chemical tracer is commonly used by inspectors to confirm a specific building's drain is connected to the storm sewer rather than the sanitary sewer?

Accepted Answer

Optical brighteners or fluorescent dye

Answer

Fluorescent dyes (such as fluorescein or rhodamine) or optical brighteners are introduced into building drains and detected downstream in the storm sewer to confirm an illicit connection.

Question 4

When an IDDE inspector discovers a confirmed illicit discharge from a commercial facility, what is the appropriate immediate response?

Accepted Answer

Document findings, notify the appropriate regulatory authority, and require the discharger to eliminate the connection within a specified timeframe

Answer

Confirmed illicit discharges require documentation, regulatory notification, and an enforcement action requiring the responsible party to eliminate the source within a permit-specified timeframe.

Question 5

Which of the following best describes a 'sanitary sewer cross-connection' in the context of an MS4 system?

Accepted Answer

A physical connection between a building's sanitary drain and the storm sewer that allows sewage to enter the storm system

Answer

A sanitary sewer cross-connection occurs when a building's plumbing — either intentionally or by error — routes sewage into the storm sewer instead of the sanitary sewer, causing illicit discharge.

(CSM) Certified Stormwater Manager Practice Test

(CSM) Certified Stormwater Manager Practice Test

CSM Illicit Discharge Detection & Elimination (IDDE) 2