Study On Lateral Flow Biological Aerated Filter For Sewage Treatment And Its Performance On Nitrogen And Phosphorus Removal

The research was conducted on nitrogen removal efficiency, its mechanics and influencing factors of lateral flow aerated filter when the influent was sewage; the biofilm characteristics of LBAF was also studied through analyzing of biomass, microorganism activity as well as their distribution along the flow path of the reactor; modified zeolite was used to remove effluent phosphorus and the mechanics and dynamics of phosphorus removal by modified zeolite was also investigated in the paper. The results showed:(1) Optimum operation condition of the reactor was determined through experiment, and optimum air/water ratio was 10:1, optimum aeration ratio of stage A and B was 1:1.(2) Simultaneous nitrification and denitrification was identified through analysis of nitrogenous compounds along the flow path of LBAF under thorough aeration, and additional OUR, substrate oxygen adsorption rate as well as bacteria count acted as supplement; the experiment was conducted under a series of hydraulic loadings and pollutants loadings to observe performance of nitrogen removal in LBAF. The results showed, total nitrogen removal efficiency was affected little when hydraulic loadings was less than 0.43m3/(m2·d); study on organic and ammonia nitrogen loadings showed, removal efficiency of ammonia nitrogen and total nitrogen decreased with the increase of influent organic and ammonia nitrogen loadings, with discrete data, removal efficiency of total nitrogen was unstable.(3) According to the virtue of flexible aeration control, under the condition of pre-denitrification, total nitrogen removal efficiency was studied under different anaerobic-zone/aerobic-zone ratio and reflux ratio, respectively. The results implied the ratio between anaerobic zone and aerobic zone had little effect on organic substrate, ammonia nitrogen and total nitrogen removal efficiency, and the ratio of 1:4 should be better allow for saving power consumption; when reflux ratio increased COD and ammonia nitrogen removal efficiency changed little , while total nitrogen tended to be decline, though analysis, excessive hydraulic loadings resulted in poor contact between sewage and filler was thought to be on one hand there was frequent backwash, and on the other hand, nitrification was bad due to insufficient reaction. So the reflux ratio should be 1:1. Finally, compare pre-denitrification with complete aeration process, total...