Sludge dewatering in Circular Economy

Circular economy and re-use of waste materials

The change of mentality to a circular economy has revealed the importance of reusing and energy recovery from sludge as secondary raw material

Circular economy and re-use of waste materials

Nowadays, the rise of the circular economy and the progressive abandon of the linear economy (throwaway culture), the secondary raw materials receive a special importance. The energy recovery and the re-use of generated by-products are core structural sections of this philosophy.

Recently, the MAPAMA (Spanish Ministry of Agriculture and Fishing, Supply and Environment) has published the draft of the Spanish Strategy for the Circular Economy. In the part Strategic Goals, it talks about the necessary “collaboration, participation and implication of the whole society” and the economic sectors. Specifically, the third point addresses the generation and waste reusing.

“To favor the effective application of the waste hierarchy principle, promoting the prevention of their generation, encouraging the re-using, strengthening the recycling and favoring his traceability”.

In this way, dewatering, energy recovery and sludge re-using are essential for the optimization of industrial waste water treatment processes. The water recovery from sludge means an important saving -economically and resourcefully (raw materials, space, energy…)- at the moment of managing this sludge, for composting, biodigestion, transporting up to an authorized center of waste management or, at worst, dumping in landfill sites.

Dewatering is the most important process when is necessary to remove the water from sludge. Traditionally, dewatering by artificial means have been carried out by machines of pressure procedures (belt filter), dynamic procedures (centrifuge) or by generation of over-pressure (filter press) or depression (vacuum filter).

Throughout history many sectors have chosen the most appropriate method to dehydrate sludge by technical and economic criteria. However, the Filter Press has been the most used equipment universally to carry out the sludge dewatering thanks to its great filtration area and the high degree of dryness that it reaches.­

Filter Press Advantages

The passage of time and the technology have improved gradually the Filter Presses. Original problems have been solved by different mechanisms that have provided extraordinary performances in all kinds of industries (foodstuff, lacteal, paper, meat, wine, metallurgical, chemical, recycling …).

The main attraction of the Filter Presses is the great filtration area in relatively small spaces. Furthermore, there are a lot of advantages that they have turned the Filter Press Draco® into one of the worldwide most demanded equipment for sludge dewatering.

•Large filtration area in a short space.

•Maximum dewatering.

•Minimal workforce for the cakes unload.

•Automatic wash in short time.

•Energy savings in connection with belt filters and centrifuges.

•Low chemical consumption.

•Low maintenance.

•Process flexibility-easily accommodates fluctuating inlet consistency.

•User friendly-simple, safe & reliable operation.

•Great cake dryness. More than 30% in biological sludge, up to 50% in some cases.

The high level of dryness that cakes can reach gives more advantages:

•Cakes drop easily. It does not need a worker to unload them.

•Reduction of storage costs and sludge transport costs.

•Reduction of combustible in thermal drying.

The range of Filter Presses Draco® adapt to the different industrial sectors with a great variety of sizes, volumes and optional mechanisms that facilitate the maintenance and the energy saving. In addition the option to containerize them is available to install them in places with complicated logistics or space limitations. In this way, the containers act as authentic technical buildings of water treatment fully equipped.