It's not really dirty and it doesn't really stink either. The grease traps are worse (than the septic tanks). People think it's a dirty job but I'll tell you this, I'd rather do this than be on a hog farm.
People love to throw grease down (the drain). Bacteria doesn't break down grease, so it turns hard and doesn't go away. You shouldn't throw any type of grease down the drain.