Analysis, Modelling and Planning the Communal Sewarage Systems

The hydraulic calculations of sewage networks are done ususally by the use of nomograms being the diagrams that show the relation between the main network parameters like pipe diameters, flow rates, hydraulic slopes and flow velocities. In traditional planning of sewage networks the appropriate hydraulic values are read mechanically from the the nomograms. Another way of calculation is the use of professional programs like the SWMM5 hydraulic model and genetic or heuristic optimization algorithms. In the paper still another way of realizing the hydraulic and planning calculations is presented in which the basic hydraulic rules and formulas describing the sewage networks and their functioning are used. The numerical solutions of nonlinear equations resulted from the formulas and describing the main phenomena of sewage flows are used in the paper to solve the tasks of hydraulic calculation and planing of the networks

Mathematical modeling and computer aided planning of communal sewage networks

In the paper the basic questions connected with modeling of wastewater networks are presented. Methods of modeling basic sewage parameters and appropriate calculation algorithms are described. The problem concerns the gravitational networks divided by nodes into branches and sectors. The nodes are the points of connection of several network segments or branches or the points of changing network parameters as well as of location of sewage inflows to the network. The presented algorithms for networks hydraulic calculation concern sanitary or combined sewage nets. It is assumed that the segments parameters such as shape, canal dimension, bottom slope or roughness are constant. Because of these assumptions all relations considered concern the steady state conditions for the network. The calculation of flow velocities and the filling heights in the segments of the wastewater net are carried out for the known slopes and diameters of the canals

Computer Dynamic Modelling of Communal Sewage Networks

In the paper two algorithms of dynamic modeling of communal sewage networks are presented. It is assumed that the hydraulic parameters of segments, namely canal shape, canal dimension and roughness are constant. The goal of the algorithms is to calculate the main sewage network parameters using only the continuity equation and the Manning formula. In the algorithms, fundamental algebraic formulas describing the filling heights in the canals and the sewage flow velocities are also used. The network model based only on the Manning formula and continuity equation in difference form and not on the liquid equations as it is used commonly by modelling the sewage networks is simpler and faster in calculations. While modeling the networks fixed network structure and slowly changing sewage inflows into the canals are assumed. The forecasted inflow values are stated and the investigation presented concerns the sanitary and mixed gravitational sewage networks