Ecological appraisal of two wastewater treatment works, Anglesey (2016)

I don’t usually travel as far as Anglesey for work, but occasionally it’s nice to go further afield.  This project involved ecological appraisal of two small wastewater treatment works in north west Anglesey.  Turning down the lane to the first site, I noticed a large development on the corner, ringed in great crested newt fencing.  Fairly big clue to the main ecological concern in this area!  Tourists often just visit the island’s spectacular coastline, but inland Anglesey is famous amongst ecologists for its cornucopia of wetlands, from ponds to lakes to internationally important species-rich fens and marshes.  And this means great crested newts are frequently found.

Great crested newt photographed in Cheshire in 2014 as part of a licensed survey

Great crested newt photographed in Cheshire in 2014 as part of a licensed survey

I arrived at the entrance to the site access track to find people trial pitting in the field (!)  This is generally a big no-no in the world of great crested newts, because newts take refuge at ground level, so digging up the ground could potentially kill newts as well as destroying refuges.  Thankfully, the sheep had cropped the field so short beforehand that the chances of there being a newt hiding there were essentially zero.  Awkward conversation avoided. Success.

The treatment works itself was quite typical – usually a wastewater treatment works will have fairly short mown grassland and/or hardstanding around the main infrastructure, and often, if the site has been there for a long time or is particularly rural, there will be some disused open sludge beds.

True to form, in the northern half of this site was a rectangular area covered in nettles.  Now I worked for United Utilities (North West Water) for two years, so I’m wise to this.  Nettles absolutely love sewage sludge.  It’s rich in phosphate and they absolutely thrive on it.  So if I’m at a treatment works and I see a rectangular area covered in nettles, I automatically think “sludge bed” and I keep my distance.  You see, the fun thing about sludge beds is that after a while some of the solids rise to the top, where they dry out, and a sort of crust forms, and then plants seed themselves in and what you end up with is a floating mat of nettles over an unknown depth of liquid sludge.  The really great part is that it looks perfectly safe to stand on.  Until you stand on it…  I’m happy to say I’ve never made this mistake, but I have heard legends about people having to be hosed down etc – very nasty !

I avoided standing on the nettles, but I did think it could potentially be the sort of place where newts might hang out to feed or perhaps rest during the day.  This flummoxed me a bit.  The proposed project involved removal of the old sludge bed type feature and replacement with a more modern alternative, so if there were newts in there someone was going to have to find them and fish them out so they could be removed to a safe place.  But how? I am NOT going swimming about in anything foul saturated and, anyway, even if I did, how am I going to find the newts in opaque sludge ???  Definitely not happening.  I gave the project team some more sensible options, but I’m not sure what they decided in the end.

The second site provided some interesting observations also.  The access track to this particular site is shared with a farm up the hill, and on the Ordnance Survey map there is a stream along its full length.  Given the previous records for water vole in the immediate area, I was hopeful that there might be some nice habitat.  When I arrived I was pretty sad to see that the entire thing had been recently aggressively dug out and canalised with all the trees cut down and virtually no vegetation left, just empty stony banks.  I went down to the treatment works anyway, where I found the usual hardstanding/infrastructure/amenity grassland mosaic, and also the farmer, who I’m sorry to say was less than civil to me.  It was, therefore, with some satisfaction that I noted numerous small plants of Japanese knotweed growing out of his newly dug out drain.  Along the entire length.  By next year there will be a veritable thicket of the stuff and it will undoubtedly get him into trouble with the neighbouring landowners when it inevitably spreads.  Take that, environmental destructor !


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