RE: Future17 Mar 2022 09:12
Water treatment engineering is a specialisation of mine. CSOs, combined sewer overflows have always been part of the sewage system. When the industry was nationalised, investment in phasing them out was very slow. Each amp cycle since privatisation has allowed hundreds of billions to be invested in such projects, the Thames Tideway project being a current huge one. These project take a great deal of time to plan and get past local authorities and scrutiny committees.
As for Ferripol, that is one of a log list of coagulants that are used in floc creation. I don't know of the current supply chain of coagulants but Brexit has not caused shortages of this kind in any of the quoted headlines. A lack of drivers, a world wide phenomena and worse in parts o EU than UK is the problem. And a shortage of coagulants would not have any impact on odour. Odour is due to hydrogen sulphide evolution due to stagnant zones in the anaerobic digestion stage [upstream from the coagulation stage]. Odour is one of the constant upgrades with eac amp cycle.
Discharge consents to rivers is highly managed and by the time any storm discharge is allowed it is predominantly surface run off with little raw sewage. Bear in mind, those rivers are not clean water, they have ish, birds, dad animals rotting in them, eficating in them as well as decaying vegetation. Serious overflows from storm events are getting rarer. Your smelly river is almost certainly the natural decay in the river itself and nothing to do with sewage treatment.