Investigating the applicability of waste foam concrete for phosphorus recovery in real pig wastewater based on the effect of organic matter on the HAP crystallisation method

Abstract

HAP crystallization use waste foam concrete as a calcium source, studied the impact of typical organic compounds in simulated pig wastewater on phosphorus recovery, and applied them to actual wastewater. Energy dispersive X-ray spectrometer(EDS) and SEM indicate: citric acid had a stronger inhibitory effect on crystallization compared to humic acid. Citric acid chelated Ca2+ ions, competing with crystallization ions and interfering with crystal nucleation. Humic acid hindered crystal growth through adsorption and ion exchange mechanisms. When citric acid and humic acid were added together, they competitively interacted, reducing the inhibition of phosphorus recovery. HAP crystallization alone reduced phosphorus content and turbidity in secondary pig wastewater, while combining 2 mL(5 g/L)PAM yielded favorable outcomes. Effluent phosphorus concentration was only 1.0 mg/L, with turbidity below 25. here was a noticeable reduction in Pseudomonas pathogenic bacteria from the Aspergillus phylum, along with a significant downward trend in the CL500_29_marine_group, which represents water body eutrophication. The combined method cost RMB 1.15 yuan/ton of water treated, a 26 % decrease compared to the original treatment plant. This method is suitable as an add-on unit for secondary pig wastewater treatment.