SYLLABUS (As per CBCS Scheme)

Module -2:

Design of sewers: Hydraulic formula to determine velocity and discharge. Self cleansing and non scouring velocity. Design of hydraulic elements for circular sewers for full flow and half flow conditions.

Waste water characteristics: sampling, significance and techniques, physical, chemical and biological characteristics, flow diagram for municipal waste water Treatment unit operations and process. Estimation of BOD. Reaction kinetics (zero order, 1st order and 2nd order).

8 Hours

Module Planning

Introduction:

A sewerage system is a system that contains pipes of several lengths and diameters which are very important to convey the wastewater, including domestic, residential, industrial and commercial treatment services.

Sewerage system plays a critical role in that it supports public health and environmental protection.

Objectives

1. Understand sewerage network and influencing parameters.

2. Understand and design different unit operations involved in conventional and biological treatment process.

3. Evaluate self purification of streams depending on hydraulic and organic loading of sewage into receiving waters.

Steps Involved Before the Design of Sewer:

​

• Estimate of sanitary sewage
• Design period
• Population estimate
• Area
• Per capita sewage flow
• Ground water infiltration
• Self cleansing velocity
• Maximum Velocity or Non-scouring Velocity

Following design period can be considered for different components of sewerage scheme.

​

 Laterals less than 15 cm diameter : Full development

 Trunk or main sewers : 40 to 50 years

 Treatment Units : 15 to 20 years

 Pumping plant : 5 to 10 years

Hydraulic formula to determine velocity and discharge.

Treatment process as a whole classified into 4 types