Sewage sludge as a fertilizer- A twofer

As we all know sewage sludge is not suitable to use as a fertilizer to grow crops because of the presence of heavy metals. But it will not be a limitation any more.

Sewage plant

Researchers from Masdar Institute have developed an energy-efficient, low-cost method for removing heavy metals from biosolids. The novel process has demonstrated the ability to remove over 90% of zinc and over 60% of copper from sewage sludge collected from the Masdar City wastewater treatment plant. This removal rate is significantly higher than any previously reported removal rates, and in the case of zinc, the removal was well below the tolerable concentration levels set by regulatory agencies. via(Masdar News)

Sewage sludge treatment is a high-cost and energy-intensive process. So, most of the sludge goes to landfills. Also treatment of the sludge by any means like physical,chemical or biological yields in lower amounts of useful outputs.

Dr. Shadi Wajih Hasan, Assistant Professor of Chemical and Environmental Engineering at Masdar Institute, developed the novel three-step treatment process that combines chemical conditioning, electrokinetic remediation and a post-treatment washing.

“If the UAE could convert the 26,000 tons of biosolids that are generated yearly from Abu Dhabi’s urban wastewater treatment plants into fertilizer, the environmental impact of keeping this waste out of the landfill and the economic benefits of creating a valuable fertilizer product that could be sold would be significant. I think this is an opportunity that the UAE should explore in greater depth,” said Dr. Hasan.

This treatment method is scalable to commercial level and is low-cost process. So, very soon we can see sludge disappearing form the treatment plants and being used as fertilizers on the farms. 
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