生物滤器处理海水养殖水过程中亚氮积累与影响因素

实验研究了竹环填料曝气生物滤器在处理高盐度、低氨氮负荷的海水养殖水体过程中NO2--N的积累现象,考察了进水有机负荷、NH4+-N负荷、温度、pH值和溶解氧等运行条件以及反硝化作用对NO2--N积累的影响.结果表明,在进水有机负荷为0.65～0.75kg/(m3·d)、NH4+-N负荷为0.058～0.077kg/(m3·d)、温度为20.9～22.2℃、pH值为7.50～8.14和溶解氧为7.43～9.73mg/L条件下,生物滤器内较低的溶解氧(0.91～1.36mg/L)是NO2--N积累的主要原因.同时,研究了反硝化过程中低溶解氧、不同碳氮比(C/N)及碳源类型等因素对NO2--N积累的影响,查明了生物滤器内含氮化合物的浓度变化与反硝化细菌的数量和功能,验证了反硝化过程对NO2--N积累的影响,明确了反硝化作用对NO2--N积累的促进作用.

The accumulation of nitrite nitrogen in biofilter for mariculture wastewater treatment and influencing factors

The experiment studied the accumulation of nitrite nitrogen in biofilter packed with bamboo ring while treating Cynoglossus semilaevis mariculture wastewater with high salinity and low ammonia nitrogen loading. Some operating parameters were carried out, including influent organic loading, ammonia nitrogen loading, temperature, pH and dissolved oxygen as well as the denitrification to the influence of nitrite nitrogen accumulation. When the influent organic loading was 0.65~0.75kg/(m3×d), the ammonia nitrogen loading was 0.058~0.077kg/(m3×d), the temperature for 20.9~22.2℃, pH for 7.50~8.14℃ and the dissolved oxygen was under 7.43~9.73mg/L, the low dissolved oxygen in biofilter was the primary cause for nitrite nitrogen accumulation. Meanwhile, the influential factors on nitrite nitrogen accumulation were investigated, including the low dissolved oxygen, the carbon nitrogen ratio (C/N) and the carbon source type in the denitrification process. The denitrification process was potential to create nitrite nitrogen accumulation under the operating conditions. It was confirmed that the denitrification process was affected in the nitrite nitrogen accumulates through further study on nitrogen compounds concentration variation in the biofilter and the denitrifying bacteria. The conclusion showed clearly that the denitrification promoted the nitrite nitrogen accumulates.