Addressing the challenges of combined sewer overflows: our review of knowledge gaps and solutions through systems thinking; integrated catchment management; taking responsibilities for CSOs; greater cost-sharing of wastewater use... Dr William Perry Reza Ahmadian Max Munday Owen Jones Isabelle Durance
Prof David Lloyd
10mo
Can you trace sewage flows using specific bacteriophage, as did David E. Hughes et al., many years ago, with undergrad groups ., I think on beaches and rivers? Also I’m sure you remember your Dave Stickler did similar using marked bacteria on SWales beaches where a few swimers had reported serious illnessesafterwards.
Arthur Thornton
10mo
An interesting review- worth including the UKWIR Chemical Investigations Program with respect to sources of substances. Also, I remember my surprise when I first understood how much storm water is managed in combined systems often multiples of the dry weather flow. Making separation and sustainable urban drainage a critical design and management requirement. May also be worth including the UKWIR studies using SAGIS and the apportionment of pollutant inputs to catchments. Supporting the points made regarding collaboration and cross sector engagement.
Prof David Lloyd
10mo
I think this is a prime action
A very interesting paper. I do feel that an additional author from the wastewater industry may have been able to improve it in parts. CSOs do not alleviate direct flows to WWTW. CSOs alleviate flow capacity issues within the wastewater catchments and networks (sewers, rising mains, pumping stations, storage tanks) that precede the treatment process. WWTW have additional features and processes to assist with accommodating high levels of wastewater influent. These include storm and balancing tanks for example. It is inferred that CSOs are purpose built, with perhaps some screening capability. Unfortunately not in all cases. Not all CSOs are permitted, and some (perhaps many) of them are simply a shared link between a surfacewater and foul sewer within a manhole node. These tend to be crude with little to no screening. Many wastewater overflows to environment (surfacewaters and marine habitats) generally take place via surfacewater outfalls that are linked (via combined sewer nodes). This makes the current problem, and challenge to prevent it, much greater than anticipated. The nature and composition of wastewater within individual catchments (in England) are generally well understood by the main sewer undertakers.