City of Phoenix, AZ - Project Overview

Wade and Associates, a CH2M HILL Company, is assisting the City of Phoenix in implementing a CMOM Risk Assessment and Asset Management Program.  CMOM (Capacity, Management, Operations and Maintenance) regulations have been proposed by the EPA and the Arizona Department of Environmental Quality to reduce sanitary sewer overflows (SSOs), improve municipal operations and to better inform the public when SSOs do occur.  The City of Phoenix is proactively incorporating these assessment and management procedures. Also, a Sanitary Sewer Evaluation Survey (SSES) and Inflow and Infiltration (I/I) Pilot Study will be implemented.

A Sanitary Sewer Evaluation Survey (SSES) may consist of all or some of the parts described below.  Our current involvement in the Phoenix CMOM project includes Smoke Testing within the Pilot Study Area, approximately 1,700 Manhole Inspections with GPS surveying and Hydraulic Modeling.  Wade previously completed a system-wide Flow Monitoring Program of approximately 90 metering sites throughout the Phoenix sanitary sewer system.  Wade used this information to create a computerized hydraulic model of the Phoenix sanitary sewer system.

Door hanger notification for smoke testing of sanitary sewer lines in the Phoenix Study Area will be distributed at least 2-7 days before testing in the area begins. 

Materials used are: NON-TOXIC, HARMLESS, ODORLESS, AND CREATE NO FIRE HAZARD.

>> Smoke Material Safety Data Sheet

We recently completed SSES field investigations for the
City of Kansas City, Missouri in the Brookside Study Area.
>>Smoke Test Video 

The current investigation targets areas recommended for further study to identify Inflow & Infiltration (I/I) sources and to address capacity issues in order to update the City's hydraulic model.  More information about Wade's CMOM Compliance services can be found on our corporate site: www.wadeinc.com
 ... find additional  information for this and other Wade Arizona Projects at www.wadeinc.com

SSES and I/I Studies:  The Sanitary Sewer System is not designed to handle such volumes of water as a storm can produce, so it becomes vitally important to identify where this water is entering the system. If too much water is entering the Sanitary Sewer System, it can lead to SSOs, sewage backups, and escaping of waste substances and chemicals.

One of the main goals in conducting a Sanitary Sewer Evaluation Study (SSES) is to identify and eliminate Inflow & Infiltration (I/I) Sources in the City's wastewater collection system.  Infiltration 'Inflow/Infiltration' (I/I) are common terms used for the introduction of excess water into a Sanitary Sewer System. This is typically in the form of rain and runoff from storms.

Flow Monitoring: In order to determine the volume of water flowing through a sewer pipe, the flow must be monitored and measured. Once this is done, the resulting data is used to build a computer model of hydraulic flows through the entire sewer system. This hydraulic model is highly useful in determining areas of stress, addressing capacity issues, and diagnosing problems in the sewer system.  A hydraulic model is also useful as a tool for future planning and development.

Manhole Inspections: Fifty percent or more of water entering into the sewer system, and overloading the sewer pipes, enters through manhole structures. During these inspections, our trained field inspectors survey all manhole structures and components for defects, as well as incoming and outgoing sewer lines.

Visual Pipe Inspections: Commonly called 'lamping,' this is the process of entering a manhole and using a light and mirror to visually examine all sewer pipes entering and exiting the manhole to identify early signs of pipe deterioration, root intrusion, deposition and other defects.

Smoke Tests: Smoke testing is used to augment the manhole and visual pipe inspections. Smoke testing (often referred to as a rainfall simulation test) is used to detect I/I sources in both the private and public sectors. Smoke testing is performed by placing a smoke generator into the intake chamber of a high-capacity blower placed over an isolated sewer pipe. Field crews monitoring the area document locations where smoke escapes the system at some defect or I/I source. Although not a defect, one common escape route for smoke is the vent pipe: this is the pipe emerging from the roof of a private dwelling that allows the escape of sewer gasses before they enter the residence.

Building Surveys: Smoke testing alone cannot confirm every possible I/I defect on a property. For this reason building surveys are conducted to detect and/or confirm potential I/I sources. During a building survey, crews examine private property for evidence of defects in the sewer line connections, called 'service laterals.' Such defects can lead to unwanted and potentially dangerous influx of gasses into residences. Such surveys are conducted with minimal disturbance to building residents and owners; special provisions are made to assure homeowners and occupants of the legitimacy of the survey and to communicate the importance of the information needed.

TV Inspections: This process involves transporting a closed-circuit TV camera through a sewer pipe. Engineers and technicians view the resulting footage and glean valuable data on conditions of the sewer pipe.

Dyed-Water Testing: Sometimes a simple visual inspection of a suspect I/I source cannot confirm if the source is connected to the sewer system. In this case, crews will introduce dyed-water into the suspect source. If dyed water shows up in the sewer system, the leak will be confirmed. This makes identifying leaks and breaks in the pipe much easier to identify.