[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. The questionnaire included respiratory symptoms, personal history, allergic history, and family medical history. Chest X-ray and pulmonary function tests (ventilation function and bronchodilatation test) were performed. Diagnosis of bronchial asthma was made according to the criteria in the Guidelines for Asthma Management by Chinese Respiratory Society. RESULTS: The overall prevalence of asthma was 0.38% (105/27 851). The prevalence of asthma in females was [0.45% (61/13 433)], which was higher than that in males [0.31% (44/14 418)]. The prevalence of asthma in children [0.85% (30/3510)] was higher than that in adults [0.31% (75/24 341)]. The prevalence of asthma in different occupational populations was as follows: farmers [0.61% (46/7524)], government officials and employees [0.23% (12/5252)], half farmers and half herdsmen [0.22% (4/1792)], inhabitants [0.20% (12/5865)], factory workers [0.06% (1/1808)] and herdsmen [0% (0/2100)]. The prevalence of asthma in farmers was higher than those in other occupations. The prevalence of asthma was also different in geographical locations and altitudes, 0.45% (91/20 314) in population living at 1920 - 3000 m above sea level, 0.29% (13/4462) at 3001 - 3500 m above sea level and 0.03% at greater than 3500 m above sea level. The prevalence of asthma in rural, urban, half farming and half herding areas and the pastoral areas was 0.64% (65/10 119), 0.27% (37/13 933), 0.15% (2/1310) and 0.04% (1/2489) respectively; the highest in rural areas and the lowest in the pastoral areas. CONCLUSIONS: The overall prevalence of asthma in Qinghai Province was lower than that in the nation as a whole. The prevalence of asthma in higher altitudes was lower than that in the lower altitudes, and was lower in herdsmen as compared to other occupational populations.

[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. In a sequencing batch reactor (SBR), the sludge mixture was operated under anaerobic-aerobic (A/O) condition firstly. Then, the activated sludge was conducted under anaerobic-anoxic (A/A) condition. During the experiment period of 32 d, DPB was successfully enriched. At the same time, utilizing the activated sludge that enriched of nitrifying bacteria, nitrification biofilm was grown up in another SBR. After 30 d, the average ammonia removal efficiency steadily stayed above 99%. Later, using the nitrification biofilm and the activated sludge that enriched of DPB, the A2 N system was connected for dealing with domestic sewage. After 11 d, the treatment effect of A2 N system attained steady. The total nitrogen and phosphorus concentration of effluent are 0, the nitrate concentration is 10.26 mg/L, and COD is 19.56 mg/L. The removal efficiency of COD, ammonia, total nitrogen and phosphorus are 91%, 100%, 77% and 100%, respectively. Each result shows that the A2N system is started up successfully.