Why doesn't Wisconsin control the amount of waste imported from other states?

The Federal Courts have determined that the shipment of waste across state borders is a protected activity under the Interstate Commerce clause of the US Constitution, and only Congress, with the President, can enact laws to change that. The DNR's authority is generally limited to prescribing how waste must be managed in Wisconsin, such as requirements to recycle certain materials, and regulating the design and operation of landfills and other waste handling facilities.