Towards a decentralized solution for sewer leakage detection - a review.

Area of Science:

• Environmental Engineering
• Civil Engineering
• Infrastructure Management

Background:

• Sewer pipeline leakage poses significant challenges at the city scale due to hidden infrastructure.
• Deterioration factors include physical, operational, and environmental aspects, making leakage detection costly and difficult.
• Effective sewer inspection methods (SIMs) are crucial for maintaining urban infrastructure health.

Purpose of the Study:

• To evaluate and categorize existing sewer inspection methods (SIMs) based on their Area of Impact (AoI).
• To propose a framework for sustainable sewer inspection plans.
• To balance precision, cost, time, self-sufficiency, and decentralization in sewer management.

Main Methods:

• Categorization of SIMs into three tiers (T-I, T-II, T-III) based on AoI.
• Tier-one (T-I) methods: Deterioration models, hotspot mapping for broad understanding.
• Tier-two (T-II) methods: Aerial thermal imagery (ATI), electrical resistivity tomography (ERT) for potential pipe clusters.
• Tier-three (T-III) methods: In-pipe visual and multi-sensory inspections for in-depth analysis.

Main Results:

• SIMs are classified into T-I (broad AoI, e.g., deterioration models), T-II (intermediate AoI, e.g., ATI, ERT), and T-III (narrow AoI, e.g., in-pipe inspections).
• T-I methods provide a reliable understanding of structural health and pinpoint leakage-prone sections.
• T-II methods visualize leaked plumes from defects, while T-III methods offer detailed pipe condition insights.

Conclusions:

• A sustainable sewer inspection plan should integrate at least two SIMs from different tiers.
• Combining methods ensures a dual investigation of precision and AoI.
• This integrated approach balances cost, time, self-sufficiency, and decentralization for effective sewer management.