That depends on where you live. But usually, all you need to do is reach out to a company that offers septic tank emptying Norfolk services, as this one does. In most areas of the world, the sludge from septic tanks is drained using vacuum trucks, which then dispose of that waste following the correct procedures.
Just make sure you’re working with reputable service providers when doing this. Most areas of the world have strict regulations on how septic tanks should be emptied and what needs to happen to the waste after the process. If you hire someone who doesn’t know what they’re doing, you may find yourself liable for whatever mistakes they make.
In the UK, for example, waste removal experts need to comply with local regulations and environmental law. They also need to be licensed waste carriers. And the sludge from the tanks is usually taken to water treatment plants to be processed safely.