Utilizing earlier investigations on methods to retrieve phosphorus and different components equivalent to calcium, magnesium and iron by warmth therapy of sewage sludge, the Hokkaido scientists understood that the method of volatilization, through which totally different components are selectively transformed into gaseous kinds, permitting them to be separated from the remainder of the handled ash, might be a promising method for recovering phosphorus within the type of heat-stable compounds.
Subsequently, they determined to discover the volatilization behaviour of the totally different components in sewage sludge ash below totally different chemical circumstances, particularly with and with out carbon being added throughout a sludge therapy course of involving chlorine.
This allowed them to develop an efficient approach for separating helpful phosphorus-containing compounds utilizing a mixture of chlorination steps with and with out the presence of carbon.
“The tactic we developed may be applied with decrease power necessities, decrease CO2 emissions, and decrease price than standard phosphorus restoration applied sciences from phosphate ores,” Yuuki Mochizuki, lead creator of the paper, mentioned in a media assertion. “In our technique, phosphorus is recovered within the beneficial phosphorus chloride kinds, which may also be transformed to phosphoric acid by dissolution in water.”
Considering that in Japan, the full quantity of phosphorus contained in secondary phosphorus assets equivalent to metal slag, livestock manure, and sewage sludge is equal to about half of the full quantity of phosphorus introduced into the nation, Mochizuki and his colleagues plan to check whether or not their approach might be used to cut back the necessity for phosphorus imports.