Paddle Cooler sludge dryer
Drying sludge by indirect method.
Use saturated steam.
Suitable steam pressure is 4-6kg/cm2.
The maximum capacity for one drying module is 55 tons/day (2.3 tons/hour), multiple drying modules can be easily combined.
Characteristic
Can use saturated steam from many sources, low energy costs.
Automatically programmed, simple structure, easy and stable in operation.
Corrosion-resistant steel structure makes it durable in use.
Only uses steam and electric motor so the cost is low.
High water separation efficiency, neat structure so it takes up little space for installation.
Widely applied in many industries, effectiveness has been proven.
There are many reference and visit projects in Vietnam.

Sludge treatment technology
Sludge produced in the wastewater treatment system includes (1). Physicochemical mud (2). Microbial sludge (3). Sludge produced during fine treatment such as precipitation (hardness, heavy metals...) or Fenton process. The cost of treating this amount of sludge accounts for about 50%-60% of the cost of operating the treatment system. Wastewater depends on the nature and method of sludge treatment.
Drying sludge using traditional methods such as drying is currently unsuitable due to disadvantages such as: Only suitable for small amounts of mud, high labor costs, waste of floor space, inconvenient during the rainy season. With the development of more modern technology, sludge treatment becomes more time-saving, more effective, and more economical.
Sludge treatment technology is basically divided into steps.
Step 1. Press the sludge, after this step the sludge moisture can reach about 60% -85% depending on the type of sludge press such as conveyor, screw, frame, centrifuge...
Step 2. Drying mud:

Using a sludge dryer is the most optimal way to reduce moisture, weight and volume of sludge (<20%), leading to a reduction in sludge treatment costs in subsequent stages as well as the cost of renting units. Professional transportation and treatment of sludge.
Based on the way the sludge is exposed to the heat source and the drying technology, the sludge is divided into two types
(1) Direct heating: The hot steam heated from the combustion chamber or heating device will be directly applied to the wet sludge, leading to the sludge's temperature increasing, the steam will evaporate and dry sludge will be obtained.
(2) Indirect heating: Heating with a boiler, the heat inside the device wall will be heated and provide heat to the wet sludge, the steam will evaporate and finally we get dry sludge

Economic benefits in investing in sludge dryers
With the increasing cost of transporting and disposing of sludge in wastewater treatment plants, costs ranging from 1,500 VND/Kg to 4,500 VND/kg, the treatment of sludge is by sludge pressing → Sludge drying. brings obvious economic benefits
The sludge after pressing has a moisture content of about 80%. To achieve optimal economic benefits based on fast drying time and low energy consumption, the sludge is usually dried to a moisture content of about 30%.
For example: 1000kg of mud has about 80% moisture, so the amount of dry mud in the mud is 200kg. After drying to 30% moisture, the sludge will weigh 260kg. So the amount of mud decreased from 1000kg → 260kg (3.8 times)
Through the example above, the economic benefits of sludge drying are very clear. According to investment experience in projects, the recovery time for sludge dryer investment is about 2-3 years.