investigation of capabilities and limitations of different cleaning methods for sewer lines

mechanical, hydraulic, and chemical washing methods are the most common methods for sewer line cleaning. each of these methods includes several sub methods. rodding and bucket machine are the two most important of mechanical cleaning methods, whereas high-speed and flushing are the most important hydraulic cleaning methods. acids, alkalis, surfactants, and enzymes are widely used materials in sewer line chemical cleaning. when choosing the appropriate cleaning procedure, the network conditions must be considered. studies indicate that, in general, the hydraulic method is the best cleaning method among the reviewed procedures. studies have shown that more than 90% of cities in the usa use hydraulic method to clean their sewer systems. whilst mechanical and chemical methods are employed 50% and 3%, respectively. in iran, there is no information about the comparison of sewer system cleaning methods, and it can only be said that due to the limitation of equipment, high-velocity cleaning using a water-jet machine, conventional, and empirical methods are used more. the hydraulic cleaning method in spite of its low cost has a high efficiency and uses minimum manpower.