An example could be oil (olive, almond)
sludge
<span>Sewage treatment is also known as wastewater treatment. It is
a process whereby contaminant is removed from wastewater. Thus, chemical,
biological and physical process are commonly used to remove contaminants from
wastewater and the by-products of wastewater treatment is usually inform of
solid waste known as sewage sludge.</span>
The cells are different between the different layers of a bone because each layer protects something different than the rest.
We've had the same amount of water on our planet since the beginning of time. Even though 70 percent of the globe is covered in water, less than 1 percent is accessible to us.
But now there is 6.7 billion people using that water. We're on track to be up to 8 billion people in 15 years. With our current population, there is already water stress.
