The Angostura effluent treatment plant (ETP) was installed in 2016 to treat spent wash from the distillery process through a combination of Anaerobic Digestion (low rate UASB) followed by Activated Sludge (aerobic). Despite significant investment, the new plant has not reliably met its treated effluent parameters and could only operate at around 50%-60% of its design throughput which meant that production levels in the distillery had to be restricted.
Our initial remit was to carry out a detailed assessment of the original plant and suitability where we identified a number of major design issues with the system. These included some key recommendations for operational changes (short-term) as well as some major modifications requiring capital expenditure.
The project involved:
- Conversion of the existing upflow anaerobic sludge blanket (UASB) digester to a Continuous Stirred Tank Reactor (CSTR) anaerobic digestion process
- Two-stage solid recovery process (gravity belt thickener followed by Dissolved air flotation unit (DAF)
- New double membrane roof, supplied by Wifferink.
Modifications were also made to the activated sludge system including
- A new selector tank
- Aerobic Dissolved Air Flotation (DAF) for solids separation
- A new Dynasand tertiary sand filter.
The project was installed by the German Contractor, CUSS.
We provided essential technical consultancy services to Angostura throughout the project in the following areas:
- Initial coordination of lab scale feasibility trials to prove the CSTR process on distillery spent wash
- Ongoing assistance to help implement the remedial measures
- Producing the Effluent Treatment Plant Design Specification/tender package
- Providing technical input during Contractor Design, Commissioning and Handover (including takeover/performance testing)
