Removing Effects Of Nitrogen And Phosphorus Using Aerobic Biological Technology To Treat Livestock Wastewater

As large scale livestock production develop rapidly, abundance of livestock excreta and all kinds of castoffs lead to a severe environmental pollution. It also becomes the restricted factor to develop itself. The pollutants from the livestock production are becoming the third source of pollution after industrial wastes and domestic garbage. The contaminants are composed of harmful gases from animal body, excreta, scraps and feathers, as well as the washing water from the livestock production factories. There are many methods to cope with the breed aquatics' wastes but not easy. Environmental biological ways have been proved to be the key methods to clean the livestock waste water. This paper is probing the biological effects of the aerobic microorganism and constructed wetland technology.The Aerobic biological technique aimed at studying the nitrogen removal under the shortcut nitrification-denitrification condition. The influences of the fators including pH, NH₄⁺ -N Load, carbon nitrogen ratio (C/N) and dissolved oxygen (DO) in the SBR system on the HNO₂ accumulation were investigated. The method to achieve the shortcut nitrification- denitrification and how to reach a stable accumulation of HNO₂ by changing the running parameters in the SBR system were also explored.The results are summarized in the following.(1) When the pH value was too high, the activity of Nitrosomas will be affected and the accumulation of nitrite will decrease accordingly. The pH value affects the concentration of FA. When it was 8.5, the best denitrification purpose was achieved and the accumulation of nitrous acid is also high. When parameters of feed-water (such as concentration of ammonia nitrogen, bubble amount, and pH value) were well controlled, a relatively high load was favorable to the accumulation of nitrous acid and may result in a good denitrification effect. Too high an ammonia nitrogen load was good to nitrobacteria. However, would influence the activity of Nitrosomas. On the other hand, since Nitromonas was adapted to an environment with a high FA concentration, its activity will increase to a certain degree as well. With ammonia nitrogen load of feed-water, DO and pH value maintained, change of feed-water COD value will exert an influence on the accumulation of nitrous acid. When C/N=7, the amount of accumulated nitrous acid reaches a maximum. At this time, denitrification effect and COD removal rate are also the best.(2) In the SBR system, on the condition that F/M, C/N, pH, MLSS, and temperature remain constant, the concentration of DO was well correlated with that of three-nitric. When DO concentration was 3.0mg/L, the accumulation rate of nitrosonitro and the concentration of ammonia nitrogen in water discharge reach 85% and 0mg/L respectively. Favorable short-range nitifying and denitrifying purposes are obtained. With DO value kept under 2.0mg/L-7.0mg/L, the SBR system operates normally. When DO was at a concentration other than 7.0mg/L, removal rate of total nitrogen reaches 99% and that of COD maintains at about 95%, and the quality of water discharge is favorable.