Hydraulic calculation of group water intakes on underground wells equipped with pumps with variable speed drives

Summary

The use of variable speed drives at group water intakes on underground sources in water supply systems is aimed at saving electricity, ensuring efficient operation modes, improving the management engineering; however, without sufficient justification the desired result is not always effected. One of the reasons is the lack of calculation using an effective mathematical model that describes the movement of water in aquifers, wells, lift pipes and gathering mains, taking into account all the existing limitations, including the mode parameters while using variable speed drives in some or in all submersible pumps. The model is submitted in the form of an optimization task where the target function is the total power input of all the operating submersible pumps. The proposed optimization model provides for describing the modes of the group water intakes operating from the intake external boundary to the tanks. All the limitations of the optimization task can be divided into three non-overlapping groups as follows: balance, technologic, and performance ones. Having calculated the electricity consumption for all significant modes during the year and compared them with the costs at the existing modes without variable speed drives, we can make a reasonable conclusion about the applicability of a variable speed drive in one or more submersible pumps. The proposed model provides for arranging both efficient and technologically allowable operating modes.

Key words

frequency converter , water well , aquifer , submersible pump , hydraulic head , flow distribution task , optimization task , energy input , group water intake

About Necessity of Revision of Standard Silicon Content in Potable Water

Summary

Substantiation for increasing the value of allowable concentration of silicon dissolved in potable water is made; it will bring the domestic normative documents into accord with international standards, ensure more rational use of resources. In Russia the maximum allowable concentration of silicon is established in SanPiN for anthropogenic silicon and silicon used for water treatment that’s why the limitation on the use of natural water containing natural silicon is unlegitimate. The literary review of water desiliconization technologies is done. Data on reduction in content of dissolved silicon in the course of deferrization and demanganization of underground water with generation of coagels, reciprocal precipitation and sorption on ferriferous deposits generated are presented. In the course of intraformational deposition, reduction in silicon content up to 35–50% is reached.

Key words

potable water , ground water , aquifer , silicon , intraformational deposition