问题 问答题 简答题

活性污泥法处理系统运行中经常遇到的由微生物引起的主要问题有哪些?这些问题各有什么样的特征?

答案

参考答案:

活性污泥在运行中最常见的故障是在二次沉淀池中泥水的分离问题。造成污泥沉降问题的原因是污泥膨胀、不絮凝、微小絮体、起泡沫和反硝化。

(1)丝状菌引起的污泥膨胀

丝状菌在絮体中大量生长以致影响沉降。

(2)非丝状菌引起的污泥膨胀

与散凝作用有关,当游离细菌产生菌胶团基质时,就会导致污泥膨胀,通常称这种膨胀为菌胶团膨胀或黏性膨胀。

(3)不凝聚

时一种微结构絮体造成的现象。这是因为絮体变得不稳定而碎裂,或者过度曝气形成的紊流将絮体剪成碎块而造成的运行问题。也可能是细菌不能凝聚成絮体,微生物成为游离个体或非常小的丛生块。

(4)微小絮体

含微小絮体的污泥不会在出水中形成高浓度,因为其颗粒比不凝聚污泥要大得多。

(5)起泡沫

自从使用了不降解的“硬”洗涤剂以来,常常在曝气池中出现很厚的白色泡沫。微生物造成的泡沫是另外一种很密实的、棕色的泡沫,有时在曝气池中出现。

单项选择题

Florence Nightingale is most remembered as a pioneer of nursing and a reformer of hospital sanitation methods. For most of her ninety years, Nightingale pushed for reform of the British military health-care system and with that the profession of nursing started to gain the respect it deserved. Unknown to many, however, was her use of new techniques, of statistical analysis, such as during the Crimean War when she plotted the incidence of preventable deaths in the military. She developed a method to prevent the needless deaths caused by unsanitary conditions and the need for reform. With her analysis, Florence Nightingale revolutionized the idea that social phenomena could be objectively measured and subjected to mathematical analysis. She was an innovator in the collection, interpretation, and display of statistics.

Florence Nightingale’s two greatest life achievements-pioneering of nursing and the reform of hospitals-were amazing considering that most Victorian women of her age group did not attend universities or pursue professional careers. It was her father, William Nightingale, who believed women, especially his children, should get an education. So Nightingale and her sister learned Italian, Latin, Greek, history, and mathematics. She in particular received excellent early preparation in mathematics.

During Nightingale’s time at Scutari, she collected data and systematized record-keeping practices. Nightingale was able to use the data as a tool for improving city and military hospitals. Nightingale’s calculations of the death rate showed that with an improvement of sanitary methods, deaths would decrease. In February, 1855, the death rate at the hospital was 42.7 percent of the cases treated. When Nightingale’s sanitary reform was implemented, the death rate declined. Nightingale took her statistical data and represented them graphically.

As Nightingale demonstrated, statistics provided an organized way of learning and lead to improvements in medical and surgical practices. She also developed a Model Hospital Statistical Form for hospitals to collect and generate consistent data and statistics. She became a Fellow of the Royal Statistical Society in 1858 and an honorary member of the American Statistical Association in 1874. Karl Pearson acknowledged Nightingale as a "prophetess" in the development of applied statistics.

What does the author try to prove in this passage()

A.Women can be as successful as men

B. Education plays a vital role in one’s success

C. Mathematics could be used to improve medical practices

D. A career in medical field is also available for women

单项选择题