During my last 20 years of experience working in the design of wastewater treatment plants, there were no two identical treatment plants. Each plant has its unique process, site layout and facilities. Consequently, hydraulic profiles are different and each plant was evaluated separately.
The only similarity is the concept and the procedure that was followed in order to prepare the hydraulic profile.
The following will provide the engineer with some basics needed to start doing his own hydraulic calculations by using simple excel sheet. The provided example is easy to follow and the designer may select whatever suites his case and work out his case accordingly.
A. Data Collection Stage:
The following information is important to start any hydraulic calculations for sewage treatment plants:
1. Plant Site Layout; This drawing will help identifying the location of the treatment facilities, gravity flow path, dimensions, lengths of pipes and channels ..etc.
2. Process Flow Diagram; This drawing is required to identify the average, minimum, maximum current and future flow rates in each pipe and process unit falling within the gravity scheme.
3. Piping and Instrument Diagram; this drawing will identify the location, number and sizes of minor losses for valves, tees, fittings, entrance and exit losses.
4. Existing Site Survey; this drawing will help planning the site layout and identify the location of plant facilities.
5. Site Grading and Drainage Layout; this drawing will be required to identify the top of structures / walls and the grade elevation at each process facility.
6. Plan and Profile drawings; these drawings are required to identify the invert elevations and slopes of all gravity pipes.
7. Mechanical drawings; some mechanical drawings are required when we need to obtain details not available in civil drawings such as Isometric drawings, piping plan and