Solutions for reducing septicity in pumped sewer rising mains?

As sewage is moved to treatment centres via pumped systems there is a risk of waste water becoming septic, causing odour and damage to downstream assets due to Hydrogen Sulphide emissions. Anglian Water has many hundreds of sites where chemical dosing is used to control septicity in rising mains with long retention periods, which involves transporting large quantities of chemicals to diverse sites. Every year we build many more sites in this way. We are looking for an innovative solution to reduce septicity in pumping mains, ideally we are looking for a method which does not involve chemical dosing.