Reducing Collection System Blockages Through Maintenance and Management

Pueblo, Colorado is a city of 105,000 residents, and operates more than 470 miles of sanitary sewers within it 47 square mile area. Up to 2005, Pueblo averaged about 70 sewer blockages per year, most caused by grease and roots. Blockages were maintenance-related rather than being caused by structural defects or undersized lines. By 2007, the number of blockages for the year was reduced to 36, without additional staff or equipment.Pueblo used a variety of means to accomplish this improvement. Sewer cleaning methods were revised to provide more effective results. Maintenance crews were trained intensively on cleaning equipment usage, CCTV inspection techniques using the PACP system, and the role of collection system maintenance in achieving compliance. The Wastewater Department implemented quality control via increased CCTV inspection to verify the efficiency of line cleaning.A computerized maintenance management system was implemented to allow identification of geographic areas where problems were concentrated, and intensive maintenance efforts were applied in those areas to clean sewer lines, restore full capacity, and reduce the likelihood of blockages. The Wastewater Department has increased the use of root cutting and tap cutting to improve access to all sewer mains for maintenance and inspection.In addition to modifying its maintenance procedures, the Wastewater Department implemented a public education program aimed at reducing grease in sewer lines using newspaper ads, television ads on the government cable channel, presentations to elementary and middle schools, and door hangers in neighborhoods where grease-caused blockages occur. The Wastewater Department also educated the City Council regarding the condition of the sanitary sewer system, and secured significant wastewater rate increases to fund sewer rehabilitation.