UDR SOLUTIONS FOR BIOSOLIDS
The biosolids from waste water treatment plants are best anaerobically digested rather than incinerated or hauled off to landfills. The result is reducing traffic and pollution while gaining renewable energy. If need be we use the gained liquid from our UDR process to maintain the biosolid feedstock at 8 – 15%. There might be no need to dry initially. If need be, the biosolids are hygienicised at 70 degree C for one hour before being pumped into the Upflow tank. The digestate yields an odor free soil amendment. If the liquid digestate cannot be returned into the WWTP, a membrane bio reactor will allow the clean water to flow into the bay.
> Our standard UDR system range from 125kW electric to multiple MW. The tonnage of available biosolids and its solid content and methane potential allow calculating the number of standard U, D and size of the Reflow tank. The generated energy is fed into the utility grid at an renewable energy premium price and sold at a flat rate at the location during peak hours and seasons. If not used, heat is converted to more electricity.
> For example, 2 Up flow, 1 Down flow and a 24m dia by 8m high double membrane Reflow tank process 50,000 t at 13% dry matter Daily biogas production is some 5,500 qyd with 52% methane content. The CHP is sized at 400kW electric plus heat that can be converted to more electricity.
> Biogas cleaning and upgrading to pipeline quality is an expensive process and can only be justified for some 50,000 t per year at 30% solids. The fast pressure swing adsorption (PSA) process is at present our preferred upgrading method. Compressed bio methane is a desirable clean burning and high energy vehicle fuel.
> Long term fixed feed in agreements for renewable energy will allow us to finance, build, own and operate the plant if desired.