Having enough time, money and resources to maintain deteriorating sewer systems is the leading challenge municipalities and wastewater professionals face. Under these circumstances, it is more important than ever to work smarter—not harder—and to direct resources where they are needed most. Doing this takes strategy and planning. That includes gaining a system-wide understanding of infrastructure condition and prioritizing resource allocation for the best return.
The traditional approach to sewer inspection relies on deploying a crawler in every line. This is time consuming and labor intensive. Newer technologies are helping sewer crews identify lines that don’t need crawler inspection—and doing so at a fraction of the cost and time CCTV requires. One leading approach to combining existing and new technologies into a single, integrated workflow is the Phased Assessment Strategy for Sewers (PASS). PASS is divided into three phases:
- Zoom camera survey to see if a pipe needs additional attention
- Video nozzle for post-cleaning assessment
- CCTV crawler only for pipes that need a thorough inspection
During Phase 1, sewer pipes are surveyed with a zoom camera–a pole-mounted video camera that is lowered into a manhole to look into adjoining sewer lines using high-powered zoom optics and focused illumination. Sewer lines don’t need to be cleaned before a zoom camera survey, which means they can be assessed quickly by a single operator. The assessment identifies exactly which pipes are clean and defect free. If defects are observed or cleaning is required, the pipe is flagged to proceed to Phase 2. Otherwise, it is marked as “PASS.”
After cleaning and clearing obstructions identified in Phase 1, Phase 2 utilizes a video nozzle–a water-propelled HD camera that threads on a jetter hose–to gather more detailed visual information about the condition of the pipe. Often, cleaning is all the pipe needs, but cleaning can also reveal hidden defects. If defects are observed, the line is flagged to proceed to Phase 3. Otherwise, it is marked as “PASS.”
Due to the labor and costs associated with CCTV crawler inspection–an average of $1.25/ft–it’s smart to use CCTV inspection only out of true necessity. And only about 25% of pipes in most collection systems need CCTV inspection. Phase 3 of PASS uses a CCTV crawler to reveal the highest level of detail, which is needed to prioritize and plan the appropriate maintenance. With PASS, crawlers are directed to where they’re needed rather than wasted on lines that are perfectly fine. No inspection program can be without a CCTV crawler, but it should be the last line of defense, with zoom cameras and video nozzles used as rapid, low-cost screening tools.
Implementing PASS reduces the cost of sewer inspections by approximately 34% and increases productivity by approximately 17% compared to CCTV-only pipe inspections. PASS provides a systematized, scalable process that:
- Utilizes the latest industry technology and best practices
- Reduces costs and ensures labor and resources are directed to where they are needed most
- Improves response time for inspection and repair
- Helps in maintaining current assessment information
Ultimately, PASS helps the crews on the front lines to work smarter, not harder. For a detailed guide to PASS, read Envirosight’s white paper Phased Assessment Strategy for Sewers: A plan for understanding sewer system condition quicker, with fewer resources.