I used to think the most unpleasant part of brewing was digging out the mash tun and boiler hops after a brewday but you get so used to it it's just another part of the process. Today, on a quiet holiday week Wednesday after a year of brewing I decided to clean out the separation tank.
The separation tank is something demanded by Thames Water and The Environment Agency. It is a 1.2M deep plastic tank in the floor with a vertical separator in it. All the brewery waste water flows into the receiving side and it gently "waterfalls" over the separation wall into the outlet side where it can be treated if necessary and then pumped by submersible pump to the sewer. All solids fall to the bottom of the receiving tank and relatively clear water overflows and gets pumped out.
I had no idea what would be in the bottom of the receiving tank. Only water, yeast and malt/hop debris goes in there and we always neutralise the ph and kill the yeast sediment with caustic soda in the fermenters before cleaning them out (live yeast leaches Oxygen in river systems). After pumping the water out with a submersible pump I uncovered about a foot deep layer of pretty stinky sludge at the bottom of the receiving side. I suppose big breweries pay for a tanker to suck it out but as we are small I laid on my stomach on the wet floor and emptied it with a bucket into a plastic dustbin. All I can say is that it reminded me of the look and smell of a pit latrine in West Africa! It's all organic though and stinky or not, it will find its way onto our veggie patch.
The tank now smells as sweet as violets though I don't. Clothes straight into the washing machine and shower is required. At least it's only once in a year.
