Study on the capability of the new biochar substrate for nitrogen and phosphorus removal

Abstract:

The biochar substrate is a new type of filler. In this study, we detected the physical properties of biochar substrate, and investigated the effect of adsorption biofilm in treating artificial wastewater and pond effluent compared to gravel quartz sand group. The results showed that: (1) the main components are SiO₂, CaCO₃ and other carbonates and oxides, which are non-toxic and harmless, and the specific surface area of the biochar substrate is large (8.92 m²/g). (2) when the water temperature is around 21 ℃, the more substrates added, the more significant the effect of reducing nitrogen and phosphorus. When the added amount was 45 g/L, the removal rate of ammonia nitrogen at 159 h was 91.58%; when the added amount was 20 g/L, the removal rate of orthophosphate at 120 h was 94.12%. (3) at water temperature around 15 ℃, when the addition amount is 20 g/L, the ammonia nitrogen reduction effect of the group of biochar substrate is better than that of gravel and quartz sand, but the effect of gravel and quartz sand in reducing chemical oxygen demand from pond sewage is better. In summary, in addition to its own ability to reduce nitrogen and phosphorus, the biochar substrate has a stronger ability to attach biofilms, has better water purification capabilities, and has a good potential application.