Sludge treatment and management is a growing challenge for countries globally. The cost of sludge treatment constitutes to approximately half of the cost of wastewater treatment, and the quantities continue to increase as new wastewater treatment facilities are built and the existing ones are upgraded to keep up with the growing population and stricter regulations that require more treatment. In developing countries, faecal sludge management plays a key role in protecting public health and environment.
IWA Specialist Group in Sludge Management deals with all kinds of sludge including sewage, faecal, waterworks, and industrial sludge. The objectives of the group are to advance knowledge and transfer scientific and technical information on all aspects of sludge management, including production, characterisation, stabilisation, digestion, thickening, dewatering, thermal processing, agricultural reuse, production of usable materials, and ultimate disposal. Relevant to the group activity is also the integrated management of sludge with other organic wastes.
We are finally at a point that sludge is not seen as a waste but as a renewable source of energy, nutrients, organic matter and water. Resource recovery will continue to be at the center of sludge treatment and management with special emphasis on harvesting the energy value through anaerobic digestion and thermal processes, co-digestion of sludge with food and other organic waste to increase biogas production, phosphorus recovery, and beneficial use for agriculture. Agricultural use of sludge will likely be more challenging in the near future and there will be a shift towards exceptional quality sludge for land application with strict limits on heavy metals, emerging contaminants and pathogens. A shift towards wastewater treatment processes that generate less sludge either by employing pretreatment technologies or by switching from aerobic to anaerobic treatment processes is also expected. Furthermore, there is also a need for new and innovative thickening and dewatering technologies. After all, 95-99% of sludge is water and it is the water content that determines the size and design of downstream treatment processes as well as the feasibility of land application, incineration and landfilling.
In 2016, our group will continue to organize major international conferences and workshops on sludge treatment and management around the world, will produce publications to achieve wide dissemination of shared experiences and new knowledge, and will aim to offer solutions, best practices, and roadmaps to sludge treatment and management challenges faced in different parts of the world.