Apart from people with a dirty job to do, not many people ever go into this hidden bend on the private side of the Walkham near Magpie Bridge – down a track with potholes like tank traps and through the gates in a fence designed to keep out kids, roe deer and scrap metal thieves.
The Horrabridge Times and village photographer Max Law were invited in after asking a few questions about it this summer, after a week or two when the smell reminded us all it was there.
You could call it Horrabridge’s dirty little secret. But almost everyone has one like it. Yelverton has its own and so do Meavy, Buckland Monachorum and even Milton Combe, filtering sewage from uphill to the point the Environment Agency will allow it back into the watercourses. Magpie Park feeds into this one by pumping through a pipe across the river. Otherwise, it’s mainly ours.
It looks kind of crumbly and old-fashioned now but site manager Paul Hoskin is proud to say it works pretty well, with a fair bit of manual input on maintenance. Occasional overflows of half-treated sewage are allowed at times of flood but there is plenty of dilution then anyway and in 23 years Paul has never known an incident which affected the wildlife.
Until it was built, 50 years ago, the old processing plant fed a stretch known as Stinky Pool, where the local trout grew fat, if not particularly appetising.
Once, a team of one or two would have been based there permanently, cutting back the grass and vegetation when there were not valves to turn or pipes to flush out. Now it probably gets visited once a day for scheduled work and an alarm goes off in Exeter if a pump fails or something.
It’s a fairly simple operation to describe. The sewage is filtered for disposable nappies, sanitary towels, plastic toys and so on, which are scraped off the mesh, minced and squeezed out and dumped in bins to go to landfill. Then the organic waste and the water are churned and left to separate. The sludge is pumped from the bottom of the separation tank into drying beds and sucked out by a tanker once a week. Some goes into a digester plant in Plymouth to make gas, which is burned elsewhere in the processing. Some is baked down with lime to kill off the bugs. In both cases, the end product is taken by farmers to spread on their fields.
After the separation, the rest of the water is trickled through four six-foot-deep gravel beds, by rotating distributor arms, of the kind we have all seen working from a train window. Then it flows back into the Walkham.
Simple though it sounds, there is quite a lot to keep working. Pumps and valves block and fail. The distributor spiders have to be cleaned out with a kind of built-in bottlebrush arrangement. Moss grows thick on the filter gravel and has to be dug off, to keep it all working properly.
On the day we visit, all is visibly working and the smell is nothing to complain about. Sometimes, when it’s hot and muck is being turned, it can get a bit ripe. But it is nothing to do with overstretch, says Paul. All new development upstream is monitored and so far, it is within the capacity of the plant. So until somebody has a better idea, the Horrabridge Sewage Works is a neighbour we need to love.
* Back in the day, there was quite a bit of industry on that stretch of the river – including a brickworks where the visitor carpark now is and a municipal tip running along the bank upstream.
Heart of the matter – the settlement tank where water and waste are roughly separated.
The man in charge: Paul Hoskin of South West Water.
Not as simple as it looks – the pipework feeding the filter beds has to be scrubbed out twice a week and the supporting cables need adjusting to keep the whole rig balanced.
The end result – safe for fish and even insects, according to the scientists.
- For more pictures by Maxwell Law, of prettier subjects, see https://www.maxwelllawphotography.com/
AND THE REST …
Horrabridge School PTA did a great job against the odds last weekend, making a success of their fund-raising concert in spite of being bowled a stinker by the weather gods. More than 300 people braved it all to pack into the school hall and raise more than £6,500. Mad Dog McCrea brought along friends including Seth Lakeman to warm everyone up, then plugged into the Irish side of the village and got it dancing until 11 pm.
Tavistock Goose Fair coming up on Wednesday, of course. For more what’s on, check our CALENDAR
Horrabridge Times is a little late this week but we should be back as usual next Friday.