Derek works in a municipal wastewater treatment plant where he oversees the process of biological treatment. which stage of municipal wastewater treatment does derek oversee?

Tertiary Treatment stage

Explanation:

There are basically four stages of treatment of sewer/waste water

a)  Screening stage – In this stage of treatment, large objects and garbage is removed from the waste water through the use of grit removal equipment

b)Primary treatment stage (Physical treatment)

Physical processes such as aeration, filtration, sedimentation etc.  are used to remove the impurities from waste water after the screening stage

c)Secondary treatment stage (Chemical Treatment)

In this stage chemicals are used to coagulate tiny impurities into larger mass so that they can be easily removed through the process of sedimentation, filtration etc.  

d)Tertiary treatment stage (Biological Treatment)

In this stage, waste is acted upon by microorganisms that work either in the presence or absence of oxygen to remove organic impurities from the waste water.  

Thus, Derek saw the process of municipal wastewater treatment plant at the tertiary stage of waste water/sewer treatment.

answer; hypnagogic sensations)

the level of progesterone is low at the pre-ovulatory phase of the cycle but it gradually increases and the levels are high at the luteal phase. if pregnancy occurs, the level of progesterone will be high throughout the pregnancy.

if egg is fertilized and the mother gets pregnant, progesterone starts preparing the uterus for the implantation. it starts building up the lining of uterus and make it hostile of the period of pregnancy.