Calcium Iron Composites for Phosphorus Removal from Municipal Wastewaters and Its Potential Reuse in Agriculture: Case Study of Latvia

The objective of this research is to develop natural, low-cost and effective sorbent for phosphorus (P) removal and recovery from municipal wastewater treatment plant (WWTP) effluent. Mostly used phosphorus removal equipment is outdated, while the modern and effective ones are expensive, thus rarely applied in small and medium scale WWTPs in Latvia. As a result, municipalities are paying penalties for exceeding the P limits, meanwhile promoting eutrophication processes. This research intended to prepare calcium/iron composites for the P removal from municipal wastewaters, followed with the use of it as a soil amendment in agriculture. Several composite materials were obtained and characterised by X-ray Powder Diffraction, Wavelength Dispersive X-ray Fluorescence spectrometry, scanning electron microscopy and specific surface area. The composite material has been preliminary tested in batch scale with a standard phosphate solution to evaluate the phosphorus recovery and the potential phytotoxic effect.