A demonstrated operation of a swine wastewater denitrification reactor filled with commercial sulfur powder used as soil pH conditioner

Abstract

In order to develop a simple method for removal of nitrogen in swine farming wastewater, a demonstrated operation of sulfur powder filled reactor was carried out at a swine farm and evaluated the performance of the reactor. Commercial sulfur powder was supplied as soil pH conditioner. The reactor to for effective was about 23L in volume with 15cm in liquid depth. The reactor was filled with 5kg sulfur powder (nominal sulfur bed volume about 5L, layer thickness 3.3cm). Purified swine wastewater treated by activated sludge process was fed to the reactor as influent. The removal rate of NO_x^--N increased gradually, and reached to about 52% after 21 days with an NO_x^--N loading rate of approximately 0.6kg-N/m³/day. Value of "NO₃^--N+ NO2₂^--N+NH₄³⁺-N×0.4" in the reactor effluent dropped to about under 100mg/L which is the national minimum effluent standards of Japanese Water Pollution Control Law. SO₄^2--S was produced by the treatment, though nitrification of NH₄³⁺-N did not occur. It suggested that SO₄^2--S was derived from denitrification process. Simple denitrification reactor using the commercial fine sulfur powder would be applicable for practical use.