Pilot Plant Test Study On Deeply Processing Urban Sewage With Biological Aerated Filters

Taihu Lake Basin Water Town, as an important area with rapid urban development in China and a key element of cities around Taihu Lake, has gone beyond the traditional concept of town, the industrial enterprises are particularly dense, urban wastewater treatment plant accepts large amounts of industrial waste water based on printing and dyeing wastewater, and such mixed waste water has complex components, high impact load and poor biodegradability. In this paper, Jiangsu Luzhi Town mixed industrial waste water is taken as the research object, and biological aerated filters are used for deep treatment aiming at water quality characteristics of mainly printing and dyeing Secondary biochemistry of the water . The paper studies the removal effects of the reactors on COD_Cr, ammonia, TP, turbidity and other pollution substances under different working conditions in the aspects of gas-water ratio, hydraulic loading, filter layer heights, and the like, thereby exploring the best operation process parameters, and the biological aerated filters micro-organisms carries on the observation, For further optimization of process provide preliminary biological basis.This paper systematically studied the influence of process parameters of biological aerated filters, such as gas water ratio, hydraulic loading (ie, HRT), and different heights of filter layers, on the removal effect. The results showed that: the biological aerated filters have the best removal efficiency on pollutants when the gas-water ratio was 3:1, hydraulic loading was about 0.63～0.94 m3 / (m2.h), the temperature was 23 OC 28 OC, pH value was controlled at 7.6 to 8.3. The removal rate of NH3 +-N, COD_Cr and turbidity respectively reached 37%, 31.5% and 51.6%, but the conditions had no prominent influence on turbidity removal efficiency.The removal condition of biological aerated filters on various pollutants along the height of filter columns showed that the removal effect on organic pollutants (COD_Cr) was manly generated in the range 105cm behind the water feeding end, the removal rate was 38.7%, accounting for 64.8% of the total removal rate; the removal of ammonia was mainly acted on 90cm 120cm section in the filter layer, the removal rate reached 32.7%, accounting for 50.6% of total removal rate; and the removal effect on turbidity was acted on 90cm away from the water feeding end, and the removal rate achieved 42.6%, accounting for 49.6% of total removal rate. With the increase in BAF height, biomass was declining, the total activity of dehydrogenase also reduced, but the biological activity of unit cell count declined little, the condition indicated that biofilm at the top of BAF had higher activity, which was conducive to degradation of organic matter. In order to ensure the activity of the biofilm, the reactor must be periodically flushed to remove the attached inert material and aged biofilm, clear the connection channels between active carbon surface and the internal pores, promote ingestion of biofilm on nutrition and nutrient, and recover the activated carbon absorption features.The identification results of microbial populations showed that: With activated carbon for packing biological aerated filters the microorganism communities were changed greatly along with seasons, the microbial populations on the upstream and downstream of activated carbon treatment unit, sampled at the same time, were closer, and the microbial populations with advantages in BAF with stable operation include Sulfurihydrogenibium, Nitrosospira and Chitinophaga.