Sewer Cleaning and Inspection
As was discussed above, there are many potential problems in sewer system networks because of their age, potential deterioration, blockages which slow down the flow of the waste material or bring it to a halt, collapsed and leaking pipes, infiltration of water, flooding, and the entire massive concern of combined sewers. Debris and foreign material along with grit, sand, fatty deposits, roots of trees, and accumulations of biosolids help produce the blockages which lead to backups in houses, odors, and/or dangerous hydrogen sulfide gas buildups.
Adequate funding for inspection and maintenance programs is lacking in many communities. Legislative bodies do not like to fund that which they cannot see even though poor infrastructure in these systems can lead to numerous complaints and even serious hazards and eventually cost more than the original repairs.
In order to counteract the serious problems in our sewage system infrastructure, it is necessary to have an appropriate inspection program, sewer cleaning, and replacement of pipes hopefully before they start to leak and collapse. Some 90% of sewer main backups are in pipes with a 12-inch diameter or less.
Serious problems can occur when personnel conducting the inspections improperly dispose of the materials and chemicals which have been gathered together during the cleaning process. Also there are concerns about the handling of chemical dyes, which are powders, and the evaluating instruments that may become coated with petroleum products and pose a fire hazard especially if there is a buildup of gas in the sewer line.
Gravity sewers have gradients downward so that they should be self-cleaning from the velocity of the fluid. However, this is compromised by debris entering the system, pipe settlement causing a loss of gradient, buildup of fats, oils, and grease, pipe collapse, and infiltration of grit and sand through openings in the pipe.
Laterals from properties can cause a serious problem in releasing the sewage from the house into the surrounding ground and possibly the groundwater, especially in high groundwater areas. When the main lines in the street are fixed, this increases the flow of the sewage within the system and if the laterals are in poor shape this may lead to odors or actual leakage on the properties.