Method and apparatus for sampling liquid

A wastewater sampling apparatus comprising:

• a sample chamber having an arcuate wall shape presenting a volume, a vacuum/pressure port, a drain, a sampling tube having a first end in communication with said sample chamber and a second end in communication with a wastewater source, wherein said first end of said sampling tube remains equidistant from said arcuate wall as said sampling tube rotates within said sample chamber to set a predetermined sample volume;
• a sampling tube position controller coupled to said sampling tube for rotating said sample tube within said sample chamber and radially positioning said first end of said sample tube within said sample chamber;
• a pinch valve assembly for selectively draining said sample chamber;
• a sample balance coupled to said sample chamber for measuring the weight of said sample chamber;
• a vacuum/pressure pump coupled to said vacuum/pressure port of said sample chamber;
• and
• a system controller coupled to said sampling tube position controller, said sample balance and said vacuum/pressure pump;
• wherein said system controller directing said sampling tube position controller to position said sampling tube within said sample chamber to receive a predetermined wastewater sample volume, directing said vacuum/pressure pump to pull a vacuum on said sample chamber to draw the wastewater sample into said sample chamber, and upon receiving an oversample output from said sample balance, directing said vacuum/pressure pump to pressurize said sample chamber to force said oversample out of said sample chamber.