Protection of sewers from corrosion

Summary

Accidents on sewers accompanied by the destruction of building structures have been a most serious problem not only for the water industry but also for the entire city. In the world the damage from the deterioration of reinforced concrete sewer tunnels and in-line structures due to corrosion is estimated at billions of euros per year. A way out of the current situation with corrosion in sewers can be timely and prompt repair and rehabilitation using protective coatings applied by trenchless methods. One of the methods of sewer rehabilitation is lining the internal walls of the sewers with plate composite materials (blocks) or continuous protective coatings where polymer concrete can be used. Polymer concrete comprises a thermosetting organic binder (usually epoxy resin) and a large amount of dispersed filler (talc, aerosil, crushed quartz, basalt, granite chips, etc.). The special composition of filler materials and advanced production technologies ensures the high qualities of polymer concrete. An assessment of the technical and economic indicators of the reconstruction of existing sewers and canals using polymer concrete blocks is given. Through a realistic example it is shown that the most effective option of the reconstruction of a sewer canal while ensuring environmental safety is lining with polymer concrete blocks (segments).

Key words

reconstruction , sewerage , collector , corrosion , repair and rehabilitation operations , lining , polymer concrete

Overhaul period of water well rehabilitation

Summary

Annual construction of water wells, operation and maintenance of newly step-out wells built as back as in the Soviet era demands arranging up-to-date engineering service of these assets. Therefore, the development of advanced methods of well repair in Russia has been a critical task. Based on the regional experience it is shown that maintaining the well flow rate in the process of operation is provided by routine maintenance works. The main factor for repair and maintenance works is incrustation of the filtering well part that affects the safe yield and reduces the well flow rate. In order to maintain the design capacity a new source shall be developed or special repair works shall be carried out to restore the original capacity. The well recovery expenditures can make 25–30% of the cost of a new water intake construction. The right choice of the repair method and overhaul period determines the service time and life cycle of the well. On the basis of the regional practice the approaches to solving the well decolmatation problem are formulated. The overhaul period for the rehabilitation of colmatated wells are recommended.

Key words

water well , colmatage , rehabilitation methods , repair and rehabilitation operations , overhaul period , well life cycle

The use of polymer pipes in water supply and wastewater disposal systems of Irkutsk

Summary

Water supply and wastewater disposal systems in many Russian cities including Irkutsk are characterized by long term operation, high wear and failure rate. Rehabilitating obsolete water and wastewater networks, upgrading their parameters to the actual loading as well as meeting the current sanitary-hygienic regulations, technical and economic requirements have been the critical tasks that cannot be solved without the use of advanced technologies, materials, structures and devices. Using the example of Irkutsk city the use of trenchless technologies of water and wastewater networks construction and rehabilitation with polyethylene pipes is described. These technologies provide for reducing costs and water supply interruption periods, improving conditions of work, improving the integrity and seismic resistance of the pipelines and facilities. The practical experience proves the high technological and economic efficiency of this method. The data on the use of additional engineering tools for handling pipes made of different materials is given.

Key words

polyethylene pipes , repair and rehabilitation operations , water and wastewater systems upgrade , trenchless technologies , hydraulic bursting head , repair clamp , upset coupling