Field Inspection and Assessment
Manhole Inspections
Collection system operators are continuously mitigating the impact of Inflow and Infiltration into their systems. Every year, millions of gallons of rainwater and groundwater leak into collection systems, stressing pumps and piping and overwhelming treatment plants. One of the most effective ways to reduce this is to perform manhole inspections. With the information gathered during these inspections, problematic manholes can be identified and a targeted repair approach can be developed to ultimately achieve I/I reduction.
Vision NC's manhole inspections identify structural and I/I related defects directly related to excess treatment costs, decreased capacity, and increased risk of sewer overflows into clean water sources. Our crews use the most up-to-date manhole inspection and scanning equipment to confirm system layout, identify manhole attributes and materials, log defects, and confirm connection pipe diameters and materials. Inspection procedures and data collection is performed in accordance with NASSCO MACP standards.
Manhole inspections are becoming more common for stormwater system assessment as well. Larger municipalities are required to inventory and assess public stormwater conveyance. The same manhole inspection techniques can be applied to stormwater manholes, inlets, and junction boxes.
Smoke Testing
Tests are conducted by blowing a special, non-toxic smoke into the sewer lines. Where there is a defect, plumes of smoke will emerge. Common defects discovered during smoke testing include defective service laterals, interconnections with storm sewer, and leaks resulting from direct damage to the sewer mains and manholes. Smoke testing is considered the least expensive investigation method to identify sources of inflow. These sources can be directly related to tremendous amounts of I/I. During the testing, all defects are recorded by highly trained professionals using advanced mapping and data collection technology. Most of these defects can be repaired using trenchless rehabilitation methods.
Flow Monitoring
Vision NC embraces flow monitoring as a science. Our crews are confined space-certified for all installation and maintenance of flow monitoring equipment. All clients receive web-based data hosting to provide real-time data delivery and protected, shared access to the data for use across personnel and departments. 24-hour data monitoring with alarm protocols guarantees meter uptime and improves data quality. Clients prefer to use Vision NC's flow monitoring services for: