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.
Among those who wrote in, volunteering for a male pregnancy experiment were a female-to-male transsexual, a childless couple from Portland, Me. (the wife couldn't safely carry a baby), a male-to-female transsexual and a reader who simply wanted to be the first pregnant man. Dustin Hoffman, who had just made the movie Tootsie, in which he impersonates a woman, called to ask for a prepublication copy of the article.