Tag Archives: Alternative Resource

Sewage Sludge, A Potential New Fertilizer?

THE PROBLEM

The world’s population increases annually. With urban communities adapting to a more meat-based diet and competing for food supplies, agricultural demands are increasing exponentially. Rising agricultural demand results in the necessity for increased amount of high-quality fertilizers. Unfortunately, the main component of agricultural fertilizer is phosphorus: a dwindling non-renewable resource.

Red Phosphorus

Phosphorus, Source:Wikimedia Commons

If phosphorus was to deplete on a global basis (predicted to occur within the next 100 years), nations may succumb to pressure and resort to violence or isolationism to protect their own supply.

WHAT TO DO?

Before global conflict occurs, the world needs to find a new source of phosphorus that is both sustainable and renewable. Luckily, researchers believe they may have found a new source of phosphorus in sewage sludge.

WHAT IS SEWAGE SLUDGE?

SEWAGE_SLUDGE_SETTLES_ON_BOTTOM_OF_BEAKER._SEWAGE_TREATMENT_PLANT_-_NARA_-_543811[1]

Sewage Sludge, Source:Wikimedia Commons

Sewage sludge is the by-product of urban sewage waste produced after an incineration or combustion process. When dissolved in water, sewage sludge is a murky viscous material with floating small particles. Interestingly, sewage sludge has a diverse variety of micro-components where oxidized metals and semi-metals make up majority of the composition. The key fact to note is the high amount of oxidized Phosphorous contained within this substance.

HOW CAN SEWAGE SLUDGE HELP US

In the past, sewage sludge has been dumped into the ocean, leaked into agricultural lands before proper processing or used in construction process such as the formation of concrete. However, a new study conducted by researcher Hannes Herzel on January 15, 2016 has shown a potential recovery of over 19, 000 tons of phosphorus annually within sewage sludge that is commercially and agriculturally reusable. But, it appears that researchers do not yet have an efficient way of extracting phosphorus from sewage sludge due to limited bio-availability. Furthermore, it is not cost efficient in a lab setting to completely remove all other heavy metals and contaminants inside of sewage sludge in order to isolate phosphorus. Coincidentally, a Russian waste purification company seems to have found the solution.

The following is a YouTube demonstration of contemporary Sewage Sludge treatment in Rusecotech kindly provided by: Daniil Andreev

https://www.youtube.com/watch?v=KdrAO6plWOQ

After this treatment, the sewage sludge will be essentially free of dangerous heavy metals such Arsenic (As), Copper (Cu) and Zinc (Zn) and will also be detoxified. The resulting mixture will be safe to use as a fertilizer after further processing. In the words of Hannes Herzel, the treated product, “thus fulfill(s) the quality parameter for a P-fertilizer“.

Although the concept of reusing sewage sludge is still under development, the future of this technology is definitely promising in securing a reusable phosphorous source.

Posted By Ming Lun (Allan) Zhu