The smell has been bad this week so I’ve been talking to South Cambridgeshire District Council environmental health department. This is what they had to say:

The current position is that extensive works are currently taking place and a number of primary settlement tanks are offline. Following my previous response [example here], Anglian Water have been arranging and carrying out their proposed works. Additional preventative maintenance issues were identified, which resulted in a slight delay in the works being started, as specialist parts required to be ordered, fabricated and installed prior to the scrappers being replaced. As you may be aware there are five tanks on the site and although a major problem was identified in only one, all the others are receiving the same attention. The work on one tank is completed and it is now back online. Two tanks are currently in the process of being drained and cleaned (this was probably the cause of the recent odour). It is expected that the second tank will be running by the middle of next week and the third in approx 2-3 weeks time. These tanks are considered a priority as they are closest to Milton. When the work has been completed on these the remaining tanks situated further away will be commenced.

So the good news is that Anglian Water do appear to be taking it seriously and are getting on with the work needed. The bad news is that on the timescales he’s suggesting the work won’t be completed until the end of the Summer.