Sludge thickening

What is sludge thickening?

This process is used in wastewater treatment to reduce the volume of sludge by removing excess water. Sludge refers to the solid material that remains after the treatment of wastewater. It contains a high concentration of solids, including organic matter, bacteria, and other contaminants. “Sludge thickening” is the process of increasing the solids concentration in sludge by removing excess water, resulting in a thicker sludge.

Thickening does not involve adding a thickening agent and thickening the sludge, but rather removing some of the water, to obtain a less liquid sludge. Not be mistaken with “sludge dewatering” which involves further removing water from the thickened sludge to reduce its volume and weight, making it easier and more cost-effective to dispose of or reuse.
In summary, sludge thickening focuses on increasing solids concentration, while sludge dewatering focuses on reducing water content.


For what benefits?

The aim is to separate the water from the solids, resulting in a sludge with a higher concentration of solids, easier to handle for further process. It is more cost-effective to transport and dispose of, as it occupies less space and requires fewer resources. Here are some key advantages:

  1. Volume reductionby removing excess water.
  2. Improved efficiency: it improves the efficiency of downstream processes, such as digestion, dewatering, and drying. It allows these processes to operate more effectively and produce higher-quality outputs.
  3. Enhanced dewatering: thickened sludge is easier to dewater, as it contains less water content. This leads to improved dewatering efficiency and reduced costs associated with sludge disposal. It also results in the production of drier sludge cake, which is easier to handle and transport.
  4. Reduced energy consumption: by removing excess water from the sludge, sludge thickening reduces the energy required for subsequent processes, such as dewatering and drying. This helps in minimizing energy consumption and lowering operational costs.
  5. Cost savings: in terms of reduced sludge volume, transportation, decreased energy consumption, and optimized use of downstream treatment equipment. These savings contribute to overall cost-effectiveness in wastewater treatment operations.
  6. Environmental benefits: by minimizing the volume of sludge, it reduces the need for landfill space and decreases the potential for pollution during transportation and disposal.

What methods?

Various methods can be employed including gravity belt thickening or dissolved air flotation depending on factors such as the characteristics of the sludge and the desired level of dryness.
Each method uses different mechanisms to separate the water from the solids, such as gravity settling, flotation, or mechanical dewatering.

Gravity belt thickening: as the product moves along a series of porous belts, the force of gravity separates solids from liquid. Gravity belt thickeners are simple and suitable for a wide range of sludge types and offers continuous operation. The flocculated sludge spreads equally over the filtering belt, and the water realeased then flows freely through its meshes. Thickened sludge is scraped from the filtering belt by a HPDE scraper and discharged to a removal pump or a screw conveyor.

Dissolved Air Flotation (DAF): It involves injecting air bubbles into the sludge, causing the solids to float to the surface, where they can be skimmed off. DAF systems are effective in treating effluent with low solid concentrations and can achieve high thickening efficiency.

Centrifugal effect Sludge is fed into a rotating drum or bowl, where the high-speed rotation causes the solids to settle against the walls. The clarified liquid is then discharged, leaving behind a thickened sludge.

Our selection of products

At EMO, we can offer you a wide selection of equipment, including gravity belt thickener and dissolved air flotation units (DAF).

In addition to this range of equipment, we also provide comprehensive services to support our customers throughout the process. Our team of experts offers sludge analysis, installation, maintenance, and repair services, ensuring that your thickening systems operate at peak performance.

Contact us today to learn more about our sludge thickening product, dewatering systems, equipment, and services. Our team of experts is ready to assist you in finding the ideal solution and process for your specific needs.