Izabela Wysocka

Comparison of two precipitation methods for the orthophosphate removal from wastewater

AbstractThe article presents a comparison of the orthophosphate removal from acid and neutral wastewaters by metal dissolution and electrocoagulation methods. The metal dissolution method is based on a similar principle to the electrocoagulation method; however, metal ions are dissolved into a solution as a result of spontaneous corrosion processes. The comparison of both methods suggests that they can provide similar results of removing phosphorus from wastewater. It was also noted that both methods introduce different amounts of iron into the solution and differ with regard to the amount of iron remaining in the wastewater. This indicates a better utilization of iron ions in the metal dissolution method and it slightly limits the problem of an excessive amount of sludge. An important parameter is the pH value in wastewater after the treatment process. Wastewater purified by the metal dissolution method was characterized by a lower increase in pH, than by the use of electrocoagulation.

Wastewater parameters after the process of phosphorus compounds removal by the metal dissolution method in comparison with precipitation and electrocoagulation methods

Abstract Precipitation methods are commonly used for removing phosphorus compounds from wastewater. Chemical precipitation method, based on adding iron, aluminium or calcium salts to the treated wastewater, is often used. Another possible way of precipitating phosphates is metal dissolution method, which is presented in this paper. The main difference between these two methods is how the phosphate precipitating ions are introduced to the wastewater. This paper discusses advantages and disadvantages of the metal dissolution method in comparison with traditional precipitation methods. Differences in the secondary contamination of treated wastewater by iron ions, conductivity, total alkalinity and pH correction process; the use of recyclable wastes; and energy consumption are discussed.