washing dishes-is grease and food safe down sink drain?

some campgrounds have utility sinks by the bath house. when we are particularly dirty (greasy) pots, pans hubby will take them up there to wash. I have seen people fill a Rubbermaid type bin with all their dirty dishes and wash them at the utility sink.
anything like ketchup, mayonnaise, salad dressings get washed down the drain. anything with a chunk left in it, chunky tomato sauce, ketchup that has food pieces in it, gets scraped into the garbage. grease does not go down the drain.