Modeling of Pump Operation Conditions in Gravity-Pressure Combined Systems

Abstract

The paper presents the problem of working conditions in gravitationalpressure systems simulation. The practical example takes into account the dynamical analysis of a system equipped with 10 pump stations with different functions. Both local press stations, local stations for shallowing network and transit pumping stations between the towns were used. The model allowed to optimize the active volume of the pump station tanks, the selection of pumps, including the frequency of power on and the time of holding the sewage.

Modelling technique of interaction between pressure and gravity sewage systems

“…Values obtained for this variant are not acceptable. As opposed to the example provided in literature [3], there was no necessity to replace the subsystem pump type 3 characteristics [4] -pressure pipeline, with type 4 characteristics [4]. The necessity to make such a simplification occurs mainly in the case of long pressure pipelines where more than one "high" point is present, where it is necessary to install an air relief valve.…”

“…Omission of protection against backflow results in the backup of sewage to the initial well (in Epa SWMM, each calculation node is treated as a well connected directly with the atmosphere). An example of the analysis of the concept of sewage discharge in the commune of Niegosławice [3] using the simulation model was verified by calculations realized using the Epanet programme. The obtained results made it possible to state that: -average pump efficiencies are comparable in the majority of cases, -in the case of pumping stations located at the end of a system (including the main pumping station discharging sewage to an existing system), there is an anomaly in the form of an unjustified increase in pump efficiency to the maximum value of pump efficiency input into the model, -the mentioned anomaly may periodically lead to a distortion during the time of analysing the duration of an individual pumping cycle (rapid emptying of active volume).…”

“…Examples of the analysed gravity-pressure systems characterized by various levels of complexity pertain to theoretical examples [2], or ones based on design concepts [3] or existing systems. Fig.…”