When not on a campsite and I have to go to a drain station......
Make sure both black water and gray water are full and both drain valves are closed. I first will put on some rubber gloves. Poo is not that sanitary and I never know when I'll have to wipe my nose before hands are washed.
First open the valve to the black water tank. It might even help to have someone turn off the water pump and open the flushing valve at the toilet to eliminate any vacuum inside the tank. When the black water stops flowing lift the drain hose in order to help any "stuff" just sitting in the hose to move on into the drain hole. After the black water has been flushed I'll close the black water tank valve. I even refill some water into the black water tank, four or five bowls worth, if there are not people behind me. Then I'll reopen the black tank valve and flush the line again. This is to help dilute the pyramid under the toilet connection.
Making sure the black water tank is empty and the drain valve is closed I will then open the gray water tank and allow that water to flush the line even more. Again I'll lift the hose to help anything move on into the drain hole.
Once everything is empty and both valves are closed again I'll disconnect the drain line from the camper. While holding that end high I walk to the drain hole and there is usually a water hose to flush the line even more with. I'll then raise the hose rinsing it as I pull it out of the hole. Without letting the hose touch the ground, anymore than necessary, I'll force the hose back into the holder on the camper.
After closing the hose holder I'll then remove my gloves. I do this by first grabbing the wrist of one glove, without touching any skin, and pull it off and hold it in the still gloved hand. Then I take the ungloved hand and pull the wrist of the last glove down and that will force the last glove to capture both gloves with the clean side out so they can be handled to throw into the trashcan that is usually close to the dumping station.
If I have had any accidents or there seems to be a need for it, I'll use the dumping station water hose to clean the area and druve away the happy little camper that I am.
Now to answer your question..... No, pumps are not necessary.