Chemical Engineering @ChemengFiles.Com

Purpose of wastewater treatment:
- Achieve obtaining drinking water that is chemically and bacteriologically safe. It may be used for human consumption or have the quality needed for industrial processes. "For domestic uses, water treatment needs to ensure the exemption of tastes and odors. Furthermore, water should be improved with agents that may contribute to health, such as fluorine. - Main purposes: to reduce the BOD content, achieving the reduction of suspended solids, reduce or completely eliminate all pathogens.

Selecting the process for water treatment:
For example, in lakes and reservoirs, causing algae bloom problems of tastes and smells, but rude to the leak. This can be controlled using chemicals like copper sulfate.

Pre-treatment of wastewater:
- Use screens to pre treat surface water - Through re-sedimentation is removed suspended matter in river water - Chemical treatments: they help re-sedimentation and are also used for pre-treatment of substances very difficult to remove. They are also effective in decreasing the number of microorganisms. Chemicals that are used most frequently are: chlorine, potassium permanganate, some electrolytes and poly aluminum sulfate (Al2 (SO4) 3, among some others.
- Aeration is the first step is performed to remove Fe and Mn in groundwater treatment.

Important considerations for the treatment of water:
- The water treatment process that takes place in a plant depends on:
1. The quality that is the source.
2. The quality is expected for finished water, when the process ends.

The chemicals for water treatment, are selected based on:
1. The effectiveness needed to achieve the desired reaction.
2. The costs required for treatment.

Perhaps the most important consideration in developing a water treatment plant is to offer maximum flexibility:
1. Enabling the change to the point of application of various chemicals involved in the process.
2. Having the ability to change the chemicals used when necessary.
3. Having a proper space in order to build additional units of pre-treatment in the future.