▪ What is Sewage?
▪ Why do we need Sewage Treatment?
▪ What is Sewage Treatment?
▪ What does Sewage Treatment involve?
❖ Levels of Waste Water Treatment
▪ Preliminary Treatment
▪ Primary Treatment
▪ Secondary Treatment
▪ Tertiary/ Advanced Treatment
❖ Other Process Required after Water Treatment
▪ Sludge Treatment and Disposal
What is sewage?
Mains water supplied to households is used for many purposes, other than drinking and food preparation, notably bathing and showering, toilet flushing and the washing of utensils, dishes and clothes. Except where main drainage is not installed, the used water gravitates to the local sewer and becomes ‘sewage’. Sewage may include stormwater runoff. As rainfall travels over roofs and the ground, it may pick up various contaminants including soil particles and other sediment, heavy metals, organic compounds, animal waste, and oil and grease.
Why do we need to treat Sewage?
It's a matter of caring for our environment and for our own health. There are a lot of good reasons why keeping our water clean is an important priority: • Fisheries: Clean water is critical to plants and animals that live in water. This is important to the fishing industry, sport fishing enthusiasts, and future generations. • Wildlife Habitats: Our rivers and ocean waters teem with life that depends on shoreline, beaches and marshes. They are critical habitats for hundreds of species of fish and other aquatic life. Migratory water birds use the areas for resting and feeding. • Recreation and Quality of Life: Water is a great playground for us all. The scenic and recreational values of our waters are reasons many people choose to live where they do. Visitors are drawn to water activities such as swimming, fishing, boating and picnicking • Health Concerns : If it is not properly cleaned, water can carry disease. Since we live, work and play so close to water, harmful bacteria have to be removed to make water safe. | |
What does Sewage Treatment involve?
Sewage treatment involves:
• The removal of solids by physical screening or sedimentation.
• The removal of soluble and fine suspended organic pollutants by biological oxidation and adsorption processes. Both forms of treatment produce sludge as by-products and these have to be treated and used or disposed of in an economical and environmentally acceptable way. (See the description below on sludge treatment.) The following describes a typical sewage treatment sequence which is illustrated in Figure 1. In practice, there are many process variations employed according to locality and the standard of effluent required.
What is sewage treatment?
Sewage treatment is the process of removing contaminants from wastewater and household sewage, both runoff (effluents), domestic, commercial and institutional. It includes physical, chemical, and biological processes to remove physical, chemical and biological contaminants.
LEVELS OF WASTE WATER TREATMENT :-
1. Preliminary Treatment
2. Primary Treatment
3. Secondary Treatment
4. Tertiary/Advanced Treatment
Flow diagram :-
1. Preliminary Treatment-
1) Screening- Removal coarse solid which may clog the mechanical equipments and pipes.
2) Comminution- Grinding of coarse solid into smaller and more uniform particles.
3) Floatation- Separation of suspended and floatable solid particles from wastewater by air...