[An epidemiological study of bronchial asthma in Qinghai Province].

Objective: To study the prevalence of asthma in Qinghai Province between 2006 to 2007.

Methods: According to the geographical location and the altitude (1920 - 4500 m), stratified-cluster-random sampling was use for this study. A total of 27 851 individuals were investigated by household survey at 49 locations in 4 autonomous prefectures, Xining Municipal City and Haidong Administrative District.

[First sequencing then connecting cultivation of the organisms and fast start-up of A2N two-sludge system].

Using domestic sewage, the cultivation of denitrifying phosphorus removing bacteria (DPB) and start-up of A2N two-sludge system were investigated in a laboratory. The A2N system started up fast by using the method that first bringing up DPB and nitrification biofilm separately then connecting them in the A2N system. The enrichment of DPB used activated sludge from the sedimentation tank of a wastewater treatment plant that working about phosphorus removal.