SUDS is a step in the right direction however my understanding is that it only applies to new developments. I would like to see existing systems upgraded to comply with the standards required for new developments. I believe the most cost effective way of doing this would be to introduce more basins (flood storage reservoirs) that could better deal with high levels of rainfall. If the rainfall was diverted away from the treatment plant into basins it could then permeate in a more natural way.

Increasing capacity at the plants is expensive but there are things that could be done to improve water quality that require less investment. The installation of a phosphorus stripping plant at every treatment site could reduce the amount of phosphates discharged into the river by as much as 95%. This is only going to deal with reducing the amount of phosphates of future processed effluent. The large volumes of phosphates that already exist in the in the rivers sediment and how to deal with that would be far more costly.

Douglas

Untreated waste is not in any way an ideal solution and I am not here justifying it. But just to clarify the points you raised from our visit to the works:

There may be other measures that could be done to treat the overflow or have larger tanks (not sure – not my field), but whilst there is a combined sewage system there is always likely to be times when the sewage works will not be able to deal with the overflow. We were told that the works are designed to take three times the flow likely after a 7 day dry period (with no rain) and to design the system to run at peak would involve a works which would, for the majority of the time, run considerably under capacity. If we could turn back the clock, combined systems would not ever have been considered but that is unlikely to change for existing infrastructure. Lets hope that SUDS works for the future.

The point about capacity was that there had been discussion in the past about piping all the treated water to Seafield for outflow into the Forth. One of the reasons not to do this was that (again because it is a combined system) it would also take all the rainwater, which in an ideal world would permeate through the soil into the river system, would be taken away and what would be left of the river. I did not intend for this comment to have been made in relation to the overflow of untreated, but relates to flow of treated water back into the river system and was not a justification for the untreated overflow.

My guess is that the works will not go away and that the peak flow is the issue – any ideas?

Alison

Quote:
“without the plants’ treated water the River Almond could well be no more than a burn”

This seems a poor attempt to justify the overflow of untreated waste into the river during heavy rainfall.

Douglas