Optimization of the prospective plans of water supply
system development under the tight financing conditions

Summary

The transition to market relations determined a new for our country technology of the urban utility systems management. This technology can be presented in two stages. The first stage is the development of the water supply and wastewater disposal plans; the second one – is the implementation of these plans on the basis of the investment programs of the public utility sector. The investment programs are shaping the financial support of the development and upgrade of wastewater disposal systems by means of the investment component in the tariff; charges for connecting newly built capital construction projects and targeted financing from separate state and municipal programs, loans and credits. Under this approach the determinants are the investments and their limitation in stages and wastewater disposal system development periods. In connection with this new problems and challenges arise related to the efficient allocation of these investments in the construction of new and upgrade of the existing water and wastewater projects. Based on the developed models and methods of substantiating the structure and parameters of wastewater disposal systems a method of shaping and optimizing the options of wastewater disposal system development under the tight financing conditions is proposed.

Key words

reliability , ecological safety , redundant layout , seismic resistance , optimal management of water supply and wastewater disposal system development , quantitative indicators , tight financing

Improvement of the integrity and seismic resistance of gravity sewers

Summary

The problems of improving the integrity and seismic resistance of wastewater disposal systems have been urgent and must be solved in the process of designing prospective plans of territorial and urban development as well as investment programs of public utilities. The procedure of wastewater system structure optimization based on developing redundant layout and searching the maximum flow of the minimum weight function (minimum cost, maximum integrity and seismic resistance) is suggested. Redundant layout is developed by overlapping the predesigned sewer routes. The integrity is evaluated by the quantitative index – raw sewage amount that is generated for the certain time period as a result of an accident and pipeline rehabilitation time. Seismic resistance is taken into consideration by increasing failure rate depending on the earthquake intensity and orientation of the seismic impact. The suggested procedure takes into account seismic impacts by increasing the length of the designed sections of the redundant sewer layout. It is shown that construction of subsidiary and loop sewers improves significantly the integrity and seismic resistance of sewers.

Key words

water disposal system , seismic forces , optimization method , redundant layout , quantitative index of integrity , seismic resistance