Any idea the slope on the pipe? Sounds to me like solids are settling out causing the odor. There is no way (unless there is a pump station involved here) that the sewage is turning septic in 300m with a propoerly designed trunk line. Pipe should be inspected via CCTV to search for blockages...
A grease interceptor is definitely a great recommendation. I am surprised that if this a commercial establishment with a food prep and clean-up area that the Authority does not include you in their Pre-treatment Program as mandated by EPA. They should have local limits for FOGs (fats, oils and...
I am replacing a fixed roof anaerobic digester cover that is approximately 30 years old. The roof is steel and was repaired due to leaking about 10 years ago. I am searching for alternate materials for roof construction to increase the life of the roof. It seems that 1/4" thick steel is...
Ran into a similar situation where we used a thick epoxy to coat the inside of the manhole to avoid corrosion. Deflecting push-on joints for gravity sewers on steep slopes can be dangerous and increases the potential for I&I. May want to look at HDPE pipe.