The company, which runs an abattoir in Guildford, Surrey, admitted 10 counts of breaching trade effluent concentration limits and one of failing to install and maintain equipment, a meter to measure effluent discharges.
Guildford magistrates yesterday imposed fines of £2,500 for each of the effluent breaches with a further £2,680 penalty for the remaining offence.
Legal costs of £1,242 and investigation fees of £4,384 were also awarded to Thames Water, who brought the prosecution.
Thames Water said the offences were committed between July 2007 and April 2008 and the court heard that on one occasion, levels of ammoniacal nitrogen were found to be up to nine times higher than they should have been.
Settleable solids, including bone particles, hooves, gristle, were recorded up to more than fives times the allowed limit, while fat and oil from the carcasses were seven times the permitted levels on one occasion.
Thames Water Trade Effluent Manager Tony McHattie said after the case: "We take breaches like this very seriously. They put our sewage treatment works under incredible strain and could result in environmental damage.
"This case should serve as a warning to other companies that we will not hesitate to take action if you're disposing illegal levels of waste into our sewerage network.
"We are keen to work with firms to help them meet their legal requirements but we are prepared to take the matter to court if they disregard these obligations and do not co-operate."
Andrew Chitty, from the Chitty Food Group, said: “On Thursday 13th August 2009, Thames Water prosecuted us (The Chitty Food Group) at Guildford Magistrates Court for breaching the consent levels of our trade effluent from the plant at Guildford, Surrey.
"We pleaded guilty and were fined accordingly. In mitigation the court accepted that no environmental impact hasd occurred and that we have already taken steps to reduce our discharge.
“We are treating these breaches extremely seriously and are committed to working with experts in this area to ensure there is no future repetition.”