Given sewage is about things the community flush and effluent is about the liquid discharge from a process you may find yourself heading down a blind alley.

Wouldn't your assessement actually be a merge of the assessemnts relating to the internal operations of the abbatoir - carcas preapartion, butchery, offal handling, area clean down & disinfection?

These would not necessarily be happening at the same time meaning the influent of your waste water treatment plant will vary dependent upon time & day.

Sewage and effluent are not really one and the same thing - sewage is one very specific type of effluent.  The term "effluent" covers any liquid discharge by a process, not necessarily biological in origin.  The effluent from your process isn't the same as sewage.

I am sure there are parallels between sewage and the effluent you are dealing with, and there is probably useful information to be had from guidance on sewage.  But it isn't the same, so following the sewage guidance blindly wouldn't be good enough.

I have used this as a basis for the assessment around some of the sites where we have a treatment plant...

https://www.sciencedirect.com/science/article/pii/S2212371721000093

I think that the general consensus is that the term “effluent” be best used to describe the liquid bi-products of a process. In the case of an abattoir I imagine that this will consist of blood, other bodily fluids, and general washings etc. it would certainly be full of biological agents and need to be managed as a hazardous substances   under COSHH.  What happens then a question the answer to which I am not sure. I am assuming that the effluent  is eventually treated before it enters the common sewer? Is this by heating or the addition of disinfecting agents? I assume that the effluent cannot be discharged directly to the sewers? Is there a minimum standard for the discharge of effluent.   I suspect that it will be based on the presence of indicator species rather than actual pathogens- for example most types of E.coli are harmless, but coliforms do indicate the possible presence of other more harmful species, which might be more difficult to detect and  measure in  the effluent.

How quick is the treatment of the abattoir  waste? Is the waste collected in a tank and treated batchwise? If the is the case you should remember that the liquor will form a fairly good environment for the  multiplication of microorganisms: so the longer the stuff is kept the more of a bacterial load  it will present.  

“ The water is then treated with chemicals to neutralise the pH before being fed into the sewer.” Interesting that all the water regulator seems to care about is the pH and that no attempt is made to disinfect the water or measure what the bacterial load might be. I guess that they are assuming that sewage plant down the line will be able to cope with the effluent’s bacterial loading before discharging it into the nearest river. 

Originally Posted by: A Kurdziel

Interesting that all the water regulator seems to care about is the pH

With it entering a foul sewer there is already a high bacterial load from all the consumer flushing flowing through the pipes.

The issue for the treatment works is pH shock (sudden swing to acidic or alkali) as this stops the treatment works bacteria working effectivley resulting in them having discharge quality problems

Hi matelot1965

To quote you - "back to the drawing board"!

Are you confident that the process is appropriate in terms of environmental protection going forward? - which is not necessarily the same as what the regulator might be currently demanding - you will presumably be aware that the water companies are under lots of pressure to do far more to stop inadequately treated waste water reaching water courses.

So, it might be only a matter of time before the discharge consent licence is tightened.

If the process is right from an environmental perspective it is likely that mostly it will be enclosed - which would solve most of the COSHH type issues as an integral part of the solution.

So possibly this is one to ask a waste water engineering specialist?