EPANET is a computer program that performs extended period simulation of hydraulic and water quality behavior within pressurized pipe networks. A network consists of pipes, nodes (pipe junctions), pumps, valves and storage tanks or
reservoirs. EPANET tracks the flow of water in each pipe, the pressure at each node, the height of water in each tank, and the concentration of a chemical species throughout the network during a simulation period comprised of multiple time steps.
In addition to chemical species, water age and source tracing can also be simulated.

EPANET is designed to be a research tool for improving our understanding of the movement and fate of drinking water constituents within distribution systems. It can be used for many different kinds of applications in distribution systems analysis.
Sampling program design, hydraulic model calibration, chlorine residual analysis, and consumer exposure assessment are some examples. EPANET can help assess alternative management strategies for improving water quality throughout a system.

These can include:

· altering source utilization within multiple source systems,

· altering pumping and tank filling/emptying schedules,

· use of satellite treatment, such as re-chlorination at storage tanks,

· targeted pipe cleaning and replacement.

Running under Windows, EPANET provides an integrated environment for editing network input data, running hydraulic and water quality simulations, and viewing the results in a variety of formats. These include color-coded network maps, data tables,
time series graphs, and contour plots.

Design a conventional vertical-shaft rapid mix tank unit for uniformly dispersing coagulant in 10 MLD of settled raw water as per design parameters given below:



Detention time (t): 20 – 60 s

Ratio of tank height (H) to diameter (D): (1:1 to 1:3)

Ratio of impeller diameter (DI) to tank diameter (D): (0.2:1 to 0.4:1)
Velocity gradient (G): >300 /s

Gt: 10000 – 20000

Tank diameter (D): < 3 m

Paddle tip speed (vp): 1.75 – 2.0 m/s
Velocity of paddle relative to water (v): 0.75 x paddle tip speed

Paddle area (Ap)/Tank section area (AT): 10:100 – 20:100

Coefficient of drag on impeller blade (CD): 1.8
Maximum length of each impeller blade (L): 0.25 x impeller diameter

Maximum width of impeller blade (B): 0.20 x impeller diameter

Impeller height from bottom (HB): 1.0 x impeller diameter

Kinematic viscosity : 1.003 x 10-6 m2/s

Dynamic viscosity of water : 1.002 x 10-3 N.s/m2



Determine tank dimensions (provide a freeboard of 0.5 m), impeller diameter, paddle dimensions, number of paddles, clearance of the impeller from tank bottom, paddle rotation speed and power input requirement.