Phosphorus Recovery Using a Continuous Reactor for Struvite Production from Biologically Treated Wastewater

Phosphorus is a very important nutrient because the amount of phosphate rock is greatly decreased.  Phosphorus reserves are expected to be depleted in the future. In addition, phosphate in wastewater can cause eutrophication, which can result in decreased levels of dissolved oxygen in an aquatic environment. Therefore, the recovery of phosphorus from wastewater is a very interesting issue because it can solve the problem of shortage of phosphate rock and eutrophication. In this research, phosphorus recovery using a continuous reactor to produce struvite from biologically treated wastewater was studied. The wastewater from cow dung mixed with Napier grass was used in this research. The first part of the experiment was to find the appropriate pH value. It was found that the suitable pH value was pH 9 without the addition of other nutrients. The second part was a study of the adhesion of struvite on various materials. The selected materials for testing were acrylic, aluminum, galvanized steel, and stainless steel. The stainless-steel plate had the lowest amount of struvite on the surface. Therefore, it was suitable material for the continuous reactor. For the final part of the experiment, the developed fluidized bed reactor was conducted at 2 h of HRT. It was found that the phosphorus recovery efficiency of the reactor was 81%, which was very high. It indicated that this continuous reactor was suitable for the actual application.