There are many different kinds of sewage treatment plants which vary in the process by which they treat wastewater. Generally, they can be classified into the following types of system: 1  Activated sludge plant (ASP). 2  Rotating disc system. 3  Submerged aerated filter (SAF). 4  Suspended Media Filters (SMF).
In certain species of sea life, male pregnancy is common. The male incubates and births live young instead of the female. Human males are not able to do so, and medical risks of a male pregnancy are extreme. Transgender individuals can become pregnant if reproductive organs are left intact. A common phenomenon is a sympathetic pregnancy, where a man exhibits all the symptoms of pregnancy along with his expectant partner.
Human chorionic gonadotropin (hCG) is a hormone produced by the placenta of a pregnant woman. Early in pregnancy, the level of hCG increases in the blood and is eliminated in the urine. A pregnancy test detects hCG in the blood or urine and confirms or rules out pregnancy. During the early weeks of pregnancy, hCG is important in maintaining function of the corpus luteum.