To describe the amount of trash or garbage in Engpsh, you can use the phrase "amount of trash" or "amount of garbage." For example, you could say:

"The amount of trash in this city is a serious problem."
"We need to reduce the amount of garbage we produce."

You can also use more specific terms to describe the quantity of trash, such as "pile," "heap," or "mountain" of trash. For example:

"There's a huge pile of trash in the alley behind the restaurant."
"The heap of garbage in the corner of the room is starting to smell."
"The mountain of trash in the landfill is getting bigger and bigger every day."

Other phrases that might be helpful in describing the quantity of trash include "volume of trash," "mass of trash," and "quantity of garbage."