Can Sludge Management Be Sustainable?


Unsanitary conditions are responsible for more than three million deaths per year. In developing countries, improper sanitation is a significant reason for spreading infections.

The sludge produced has a high level of pathogens and low nutrition levels. Sludge management plays a vital role in sanitation programs by reducing health problems and associated risks.

Sewage sludge is obtained from wastewater treatment in sewage treatment plants. This sludge consists of two forms- sewage sludge and secondary sludge, also known as activated sludge in the activated sludge treatment plant.

Municipal sewage sludge usually consists of solid, semi-solid, or liquid muddy residue. This sludge contains proteins, sugars, detergents, phenols, lipids, and toxic and hazardous organic and inorganic pollutants.

Sewage is a combination of domestic and industrial waste. It is produced by residential, institutional, commercial, and industrial structures. Sludge has semi-solid slurry consistency and can be produced as sewage sludge from wastewater treatment processes.

The sludge consists of a wide range of harmful substances such as dioxins and furans, polychlorinated biphenyls, organochlorine pesticides, absorbed and extracted chlorine derivatives, polycyclic aromatic derivatives hydrocarbons, phenols and their derivatives, phthalate, and others.

How to manage sludge sustainably?
Some conventional methods of managing sludge after the treatment was using sludge in agriculture and for other land uses. However, it is restricted because of the environmental health risks involved.

Two factors to consider for sustainable sludge management are:

  1. It should maximize the recovery benefits by consuming less energy.
  2. It can be an economical and effective, innovative method or operational system.

To understand the most potent method for sustainable management of sludge, it is essential to know its composition and characteristics.

Understanding Sludge Characteristics
Five groups of components mainly characterize the sludge composition.

  1. Non-toxic organic carbon compounds, Kjeldahl-N, phosphorous-containing components.
  2. Toxic pollutants: *Heavy metals, such as Zn, Pb, Cu, Cr, Ni, Cd, Eg, and As.

The concentrations can vary from more than 1000 ppm to less than 1ppm.

Other toxic pollutants are PCBs, PAHs, dioxins, pesticides, endocrine disrupters, linear-alkyl-sulfonates, nonyl-phenols, etc.

  1. Pathogens and other microbial pollutants.
  2. Inorganic compounds such as silicates, aluminates, calcium, and magnesium-containing compounds. 
  3. Water, varying from a few percent to more than ninety-five percent.

The fundamental problem of the sludge is that all these compounds are present in one mixture. Organic carbon, phosphorous, and nitrogen-containing compounds are valuable compounds. Sustainable treatment involves the recovery of these useful products. Kjeldahl-N is primarily present as ammonia, a potential fertilizer component.

In modern wastewater treatment systems, most of the Kjeldahl-N is destructed, using a certain amount of valuable organic carbon compounds in the wastewater. In some cases, water is discarded for ease of transportation or efficient treatment of sludge.

Some of the primary treatment options that can be considered as an initial step to managing the sludge problem sustainably are:

Improving the quality of sludge This approach eliminates toxic substances from sludge. For example, if the sludge contains a high concentration of heavy metals, it can be treated either biologically or with the help of chemical leaching to obtain high-quality sludge.

Other extractions and selective oxidation processes are used if the sludge is polluted with pathogens.

Utilizing valuable compounds present in sludge.

It is another treatment option that can be considered to manage sludge sustainably. Sludge can be used to produce fuel or feedstock in the form of diesel, oil, or gas. Some other ways to use sludge would be the production of slags, bricks, and volatile acids such as formic acid, acetic acid, and propionic acids. This can be achieved by microbiological processes.

Reducing the total volume of sludge
Many processes are followed to reduce the sludge. Some of the methods mentioned earlier are removing heavy metals, removing pathogens, and utilizing organic/inorganic compounds to reduce the overall volume of the sludge.

One of the most effective ways to reduce sludge in the wastewater treatment plant is using our bioremediation technology Cleanmaxx. Our product contains a specialized, concentrated consortium of uniquely functional bacteria with a high proliferative capacity and tenacity to withstand hostile effluent waters. It rapidly reduces organic load, reducing sludge volumes in a wastewater treatment plant.

Some of the key benefits of Cleanmaxx are: 

1) Reduces COD/BOD levels even in effluents with high TDS levels and recalcitrant compounds. 

2) Promotes a high rapid biomass generation capacity in aerobic wastewater treatment. 

3) Reduces sludge volumes without making any physical change in the current system. 

Our wastewater technology makes sludge management sustainable without causing environmental side effects. To know more about our bioremediation technology, you can reach out to our experts at

Post by Karen Sam