Flies around Frome sewage works

I understand that some of you may be experiencing a number of small black flies in and around your home once again over the past few days, as one local resident contacted me about this yesterday.

These are likely to be the Chironomids, midges, associated with the Frome sewage works (water recycling centre) at Welshmill where they have been generated in large numbers in previous years. The control of the midges and the (slower flying) ‘window gnats’ were subject to much discussion and an eventual scheme of netting and monitoring enacted by Wessex Water from Autumn 2022, and I understand this has reduced the fly numbers by over 90%.

I put the problem to Wessex Water’s current Head of Water Recycling, who responded, ‘I am sorry to hear there is a customer experiencing large numbers of flies at this time … We have checked with the team and we have seen a general increase in numbers in the last week or so as is normal for this time of year; particularly during the few days when the weather was warmer and not raining a week or so ago. Our larvae and fly counts suggest that this has now peaked and the numbers are now back to previous levels. We continue with the filter nets and fly larvae dosing, in-line with best practice as per the fly management plan agreed with the EHO [Environmental Health Officer].’

So Wessex Water are aware, but I am not sure how large the problem is. If this is once again affecting a large number of people over a wide area, it would justify a site visit and an inspection by the Council’s Environmental Health team to check the agreed and required measures are being fully implemented.

So if you are seeing flies come in, you need to let Wessex Water, and the Somerset Council’s Environmental Health team know, please contact:

1. Wessex Water’s complaints line 0345 600 4 6000 (Monday – Friday 8am-6pm) or at https://www.wessexwater.co.uk/help-and-advice/customer-commitments/enquiries-and-complaints

2. Somerset Council – https://mdc.somerset.gov.uk/make-an-environmental-complaint

3. Please also let me know, so I can get an idea of the extent of the current problem, by emailing me at adam.boyden@somerset.gov.uk.

Previous news and information on this issue, including a guide to the species concerned can be found at: https://adamboyden.mycouncillor.org.uk/2023/04/17/flies-around-frome/

Which flies are from the works?

The two types of fly reported to be coming off the sewage works are (1) small black chironomids, which swarm in large numbers largely around trees but can be a big nuisance if they enter properties, and (2) window gnats which sort of float about in the air individually and in groups. The following extracts are from Wessex Water’s Frome Fly Management Plan (May 2021, Issue 8):