Membrane Processes For Waste Water Treatment

1. Membrane Processes For Waste Water Treatment By: RohitChaurasia 3rd B. Tech. Civil Engineering 71/08

2. Contents Introduction Stages in waste water treatment Conventional waste water treatment techniques Processes and equipments Membrane bioreactor processes Advantages and Disadvantages of MBR Conclusions

3. Introduction • Wastewater treatment is the process of taking wastewater and making it suitable for discharge back into the environment. • Wastewater can be formed by a variety of activities. • Using advanced technology it is now possible to re-use sewage effluent for drinking water.

4. Stages in waste water treatment • PRIMARY • SECONDARY • TERTIARY

5. CONVENTIONAL waste water treatment techniques

6. Physical/Chemical Treatment Systems

7. Biological Treatment System • Biological treatment systems use bacteria and other biological matter to break down waste.

8. Processes and equipments

9. Screening Removal System • Grit Removal System • Clarification • Filtration • Sludge Dewatering • Solar Drying of Sludge

10. MEMBRANE BIOREACTOR PROCESSES

11. Introduction to MBR • Membrane bioreactor(MBR) technology combines the use of biological processes and membrane technology to treat wastewater and provide organic and suspended solids removal. • Produces a tertiary standard effluent of 5: 5: 5 BOD: Suspended Solids: Ammonia. • Contains an ultra-filter or micro-filter membrane unit. • It can be operated in either an AEROBIC or ANAEROBIC mode, increasing the spectrum of chemicals suitable for biological treatment.

12. Membrane Technology • These processes differ depending on the type of substance to be removed. • Membrane types can be broadly placed into four categories as shown ahead:

13. Micro Filtration • Filtration by particle size. • Removes e.g. colloidal silica, oil emulsion, Collidocillus staphylococcus. • Used for wastewater treatment. • Membrane size: 0.1 - 10 μm.

14. Ultra Filtration • Selectively filters only molecules of a specified size and weight. • Removes various viruses. • Used for sterilization, clarification, wastewater treatment. • Membrane size 1 - 0.01 μm.

15. Nanofiltration • Used for partial desalination. • Removes e.g. sucrose, egg albumin. • Used for blood osmosis, blood fitration, water purification. • Membrane size: 10 - 0.001 μm.

16. Reverse Osmosis • A filtration process used for complete desalination. • Used for blood osmosis, blood filtration, water purification. • Membrane size: 10 - 0.001 μm

17. Electro dialysis • This is a process in which electrically charged membranes are used to separate ions from water solutions by the effect of a difference of electric potential. • May have up to 400 cationic and anionic membranes. • Convenient for very high concentrations (between 0.5 and 1 gram per litre)

18. Membrane materials • Some of the polymers most frequently used as materials for membranes are: • Polycarbonate. • Polyvinylidene-flouride. • Polytetrafluoroethylene. • Polypropylene. • Polyamide. • Cellulose-esters. • Polysulfone. • Polyetherimide.

19. Membrane Processes

20. Advantages and Disadvantages of MBR

21. Advantages • Cost-effective - low life-cycle costs. • Difficult contaminants degraded. • High-quality effluent produced. • Recovery of high-value products. • Recovery of energy. • Increase of productivity. • Improvement of quality. • Creation of new products. • Easy to expand the system.

22. Disadvantages • The disadvantages include: • The problem of FOULING. • Membrane malfunctioning.

23. Conclusions • Study of the effluent quality produced by conventional secondary treatment processes reveals that such treatment methods do not remove many pollutants. • The advantages of MBR show that it is the best option economically, socially, environmentally and sustainably. • Can achieve cost effective wastewater regulatory compliance.