The size of decentralized wastewater treatment system (DEWATS) can range from individual onsite system that serves one household to shared facility that serves upto five to ten households or public facility for several households. The distance of wastewater treatment from the source of generation of wastewater depends upon many considerations one of which is the reuse of treated wastewater.
Since the distance between the collection point of wastewater area and the origin point is less, therefore, elaborate collection system and equipment is avoided thereby reducing cost. The other most important aspect of this system is that the construction of this whole system is not capital intensive. Water treated can be used in following areas:
- Landscape irrigation
- Toilet flush supply
- Cooling tower makeup etc.
Treatment Technologies
Normally low maintenance treatment technologies are used for decentralized wastewater treatment system which are as follows:
- Treatment through sedimentation process and primary treatment in
septic tanks, sedimentation ponds, biogas digester's and Anaerobic
ponds.
- Treatment using secondary anaerobic treatment in fixed bed
filters or baffled septic tanks.
- Tertiary and secondary aerobic or anaerobic treatment in constructed wetlands, ponds or shallow polishing ponds.
To choose appropriate methods and technology for decentralized wastewater treatment system various considerations should be kept in mind like composition of wastewater, land availability, availability of funds and expertise etc. After going through all the considerations one can choose one or all of the following technological options. Article
Decentralized Waster Water Treatment System ( DEWATS) For Small Scale Enterprises
Case Study
Case Study: Lilo-an's ( Cebu Island)
Decentralized Waste Water treatment system Yunnan (China)