2. DEWATS stands for “Decentralized
Wastewater Treatment Systems”.
Decentralized wastewater systems convey, treat
and dispose or reuse wastewater from small
communities, buildings and dwellings in remote
areas, individual public or private properties.
INTRODUCTION
WHY WE USE DEWATS
Water is the essential basis for all forms of life.
Water is of utmost importance for human health
and dignity. Water is crucial for sustainable
social and economic development. However,
world water resources are under threat.
In the past some years, Urbanization, industrial development and the extension of agricultural production
have a significant impact on the quantity and quality of water resources. Today one-third of the world’s
population lives in countries suffering from moderate to high water stress.
While see the increasing demand for freshwater sources, we used Dewats system s to convey, treat and
reuse the waste water.
3. • It’s a Sustainable treatment of wastewater at the local level.
• DEWATS usually function without technical energy inputs.
• Independence from outside energy sources and sophisticated technical equipment provides more reliable
operation.
• DEWATS are based on a modular, technical configuration concept. Appropriate combinations of treatment
modules can be selected, depending on the required treatment efficiency, costs, land availability, etc.
• DEWATS units are quality products. Though they can be constructed form locally available materials and
can be implemented by the local workforce.
• DEWATS require few operation and maintenance skills. While most operational tasks can be carried out by
the users, some maintenance services might require a local service provider.
• DEWATS can reduce pollution load to fit legal requirements. Like all other wastewater-treatment systems,
generated solid waste (sludge) must be handled, treated and disposed of in accordance with hygiene and
environmental standards
• DEWATS consider the socio-economic environment of a given location.
ABOUT
4. TECHNICAL CONFIGURATION
The selection of appropriate
technical configuration
depends on the:
• volume of wastewater
• quality of wastewater
• local temperature
• underground conditions
• land availability
• costs
• legal effluent requirements
• cultural acceptance and social
conditions
• final handling of the effluent
(discharge or reuse)
5. TECHNICAL CONFIGURATION
Pre-treatment is done in a Settler.
A device which separates the liquid from
the solid, retention time is only 2 hours.
Pollution reduction is around 30%
First treatment takes place in a Baffled Tank .
A device with several identical chambers through which the effluent moves from top to bottom. Retention
time is 24 hours. Pollution reduction is around 80%
6. Second treatment takes place in a anaerobic filter.
A device filled with a filter material (cinder) through Which the effluent moves from top to bottom.
Retention time is around 8 hours. Total pollution reduction is around 90% At this stage CPCB(Central
pollution control board) standards are met but the effluent still has an odor.
Third treatment takes place in a planted gravel filter
A structure filled with gravel material and planted with water resistant plants, who provide oxygen to the
passing effluent. Retention time is 1½ day. Pollution reduction is around 90%
7. Post treatment takes place in polishing ponds fitted with aquatic plants and fishes. It is through this
device that the water transforms from a lifeless state into living water again.
Ponds with aquatic plants are an efficient way to combine wastewater treatment, landscaping,
aesthetics and water reuse, the pond can also act as a storage device.
8. In recent years, DEWATS have been implemented at many different locations by various institutions. Gathered
experience shows that each location demands its own approach. Below, a number of “good practice
examples/applications” of DEWATS are presented. These are not meant to be exhaustive; they highlight
different aspects of DEWATS implementation.
Advantages of DEWATS:
• Efficient treatment for daily
wastewater flows up to 1000m3
• Modular design of all components
• Tolerant towards inflow fluctuations
• Reliable and long-lasting
construction design
• Expensive and sophisticated
maintenance not required
• Low maintenance costs
Hence, DEWATS technology is an effective, efficient and affordable wastewater treatment
solution
Disadvantages of DEWATS:
• Large area requirement
• Wetland treatment may be economical
relative to other options only where land is
available and affordable.
• Design criteria are yet to be developed
for different types of wastewater in
different climatic conditions.
