Thanks all,
That grease trap had not been cleaned for 4 months and was also blocked with food particles & dozens of tea bags in the sink by dozy catering staff who couldn`t give a stuff, after reading up a bit on grease traps after the event, apparently they should be cleaned at least on a fortnight/monthly basis.
I guess you guys are right about getting rid of sludge/grease down the road drain, but the management are useless, by not providing a emergncy wet & dry vac to dispose of the excess spilling of water all over the floor, or to provide sturdy pvc bags for the grease etc.
Mind you, I did leave the lid off the tank for a few hours, which in turn closed the small cafe/kitchen for the day, i hope that taught them a lesson.
John, what exactly do you mean by a digester system? are you refering to a kind of under sink mascerator? i did mention this, but the manager refused to consider installing one due to worrying about staff plunging cutlery down it.
Cheers bertie - thats a good buy! will definately buy one of them!