Bash does not manage floating point numbers. The CPU variable stores a floating point (the cpu percentage from a ps command, I guess) hence the error:
./process: line 22: [: 0.0: integer expression expected
where ./process is the name of the script,
line 22 is the relevant line
[ is the command originating the error (yes, in linux [ is a command)
0.0 is the wrong item
the rest is the error message.
As you can see the numbers 0.0 and 0.7 in your example trigger the error.
At this point you can:
1) format the output from the awk statement, forcing the percentage of the CPU to be an integer. It will be rounded anyway, so you will lost most of its meaning, especially when it is a value between 0 and 1.
2) multiply the number by 10 in the awk statement and again print it as integer using the %d modifier. Then the test CPU -gt 0 is still valid. If you want to change the test, don't forget to multiply the threshold by the same factor 10. For example if you want to test a CPU usage greater than 0.8, you will do CPU -gt 8.