Abstract
Performance of two types of agent synthesized from amorphous silica and hydrated limes (CSH-lime, M-CSH-lime) were evaluated on advanced treatment of swine wastewater (color removal, phosphate removal, and disinfection). The agents were prepared with different raw material and component ratio. Diatomaceous earth-hydrated lime mixture and hydrated lime were also evaluated for advanced treatment as references. Treatment apparatus using the agents consisited of reaction tank (volume 6L), neutralization tank (volume 8L) that neutralize the effluent from the reaction tank, and solid-liquid separation tank for recovering phosphate adsorbing agents. Removal rates of PO43−-P and coliform bacteria by the treatment were nearly 100% with M-CSH-lime addition rate of 0.15wt/v%. Color removal was 76% with 0.15wt/v%. The performance of CSH-lime was rather inferior to M-CSH-lime. Those of diatomaceous earth-hydrated lime mixture and hydrated lime was considerably inferior comparing to the agents of amorphous silica and hydrated lime. Stable neutralization of the efflunet could be carried out with CO2 gas bubbling. Content of citric-acid-soluble P2O5 in the recovered M-CSH-lime was about 20%. The recovered M-CSH-lime had no negative effect on the germination and the growth of komatsuna (Brassica rapa var. Perviridis). Those results suggest that the M-CSH-lime was suitable agent for advanced swine wastewater treatment, and recovered M-CSH-lime might be suitable for phosphorus feritilizer.
