1. Water and Wastewater Management in Small Communities
Dr. Kazem Naddafi
Tehran University of Medical Sciences

2. Decentralised Sanitation Systems
Collection, treatment, and final disposition of the wastewater on/or close to the location;
Useful in treating wastes from residences, households, small villages, isolated communities, etc.
Advantages for decentralized systems:
Economy of structural arrangements such as transportation, reservation and elevation;
Possibility for reuse of the effluent and potentiality for aquifer recharging;
A problem in a unit doesn’t collapse the whole system;
Development of the local potentialities: small systems can be designed, built and managed by local professional, improving the local economy.

3. What are Decentralized Wastewater Systems?
Septic Systems
Onsite Systems
Individual Systems
Cluster Systems
Package Plants
Large Capacity Septic Systems

4. Ecological Sanitation (EcoSan)
Ecological Sanitation is a decentrailised sanitation system that understands human excreta, organic wastes and wastewater as a resource (not as a waste) with high potential for reuse and recycling.
EcoSan systems enable a complete recovery of nutrients in household wastewater and their reuse in agriculture. They also help preserve soil fertility and safeguard long- term food security. Moreover, they minimize the consumption and pollution of water resources.

6. Ecological Sanitation Stages

7. Septic Tank

12. SDGS - STEP

14. Septic Tank and Infiltration Field

17. Anaerobic Filter
Anaerobic filters are used for wastewater with a low content of suspended solids (e.g. after primary treatment in septic tanks) and narrow COD/BOD ratio. Biogas utilization may be considered in case of BOD > mg/l.
The anaerobic filter, also known as fixed bed or fixed film reactor, includes the treatment of non-setteleable and dissolved solids by bringing them in close contact with a surplus of active bacterial mass.
The larger the surface for bacterial growth, the quicker is the digestion.

18. Anaerobic Filter

19. Hydro Chlorinator

20. Tablet chlorinator

21. On site electrochemical hypochlorite generator

22. On site electrochemical hypochlorite generator