Abstract: A method for controlled removal of carbonate blockage from interior walls of water conduit systems having substantial reduction in flow capacity. A section of the system to be cleaned is isolated and an aqueous liquid is circulated to establish baseline liquid flow rates. An acidic cleaning composition which removes the blockage but which generates carbon dioxide gas is then added under controlled conditions to a circulating aqueous cleaning solution. The fluid flow rates and pH are monitored throughout treatment. Adjustments are made if necessary to maintain a controlled amount of carbon dioxide gas liberated. The aqueous acid cleaning solution is circulated in an open loop system with continued addition of acid until the outflow rate decreases and once again equals the inflow rate. Substantial inorganic carbonate deposits are thus removed from water conduit systems while dangerous conditions due to excessive generation of carbon dioxide gas are avoided.

Abstract: A process for pipe system cleaning and in-line treatment of spent pipe system cleaning solution prior to disposal. A cleaning solution is added to a fouled pipe system to clean the pipe system of scale or deposits. The spent cleaning solution is recirculated through the cleaned pipe system and a treatment agent is added to the recirculating spent cleaning solution. The treatment agent is recirculated until the spent cleaning solution is environmentally safe for disposal. The in-line treatment process minimizes the volume of treated spent cleaning solution and minimizes the time required to treat the spent cleaning solution.

Abstract: A method of and system for cleaning and maintaining water distribution pipes which have reduced flow due to an increase of water scale deposits, sediment and the like along the inside surface of the pipe includes a mobile cleaning unit which can be conveniently and easily connected to a pipe section to be cleaned. An aqueous cleaning solution is introduced and circulated in a first direction through the pipe section for sufficient time to dissolve and loosen scale and sediment. The flow direction of the treating solution is then reversed to break off or remove sediment or other tuberculated growth that has developed directionally with the direction of water flow in the pipe section. The turbulent flow in the opposite direction increases the effectiveness of the cleaning process in particularly troublesome and hard-to-clean pipe sections. The spent treating solution and other deposits are flushed from the pipe and the mobile cleaning unit to an appropriate waste stream.