MAXIMISING ANAEROBIC DIGESTION WITH RELIABLE MIXING

Phil Black - PII Editor 20/08/2009

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The government’s aim of achieving targets for zero food and packaging into landfill by 2015 have clearly focused attention on ways of developing technology that can contribute to a significantly reduced reliance on carbon based fuels and reducing emissions. Of particular interest to SYSTEM MIX LTD is the potential for converting problems associated with the disposal of organic waste materials into energy generation through the process of anaerobic digestion.

System Mix have worked with the UK’s water utility companies for over 15 years in various anaerobic digestion applications and during the last 10 years have witnessed a very positive change in the way that waste has been considered as a source of alternative energy. During this time, System Mix has provided specialist knowledge and expertise along with their Vaughan ROTAMIX mixing systems which has resulted in a 100% performance over the life of the plant.

The Rotamix system is a large scale mechanical mixing system that guarantees a complete mix inside the anaerobic digester by suspending all organics, fats, oils and grease (FOG), grit and non-organic solids into a homogenous mix. The system uses strategically positioned large orifice jet nozzles which create a mixing action compatible with mixing waste materials. At the ‘heart’ of the system is the Vaughan Chopper pump which allows optimum liquid velocity and pressure to be introduced at pre-determined positions inside the tank, without fear of clogging the pump or nozzles. This enables any solids that are fibrous and prone to re-weave, to be constantly reconditioned. It also maximises the effective volume of the tank by eliminating settlement of solids on the tank floor – a process best described as ‘dual zone mixing’.

Overall energy costs are comparable with existing mixing technologies due to the ability of the system to be operated on an intermittent basis, in addition to it being able to quickly move the entire contents of the tank from standstill. This also allows important maintenance to be carried out on the chopper pump that supplies the recirculation and mixing action inside the digester, without reducing the effectiveness of the digestion process.

To summarise, the features and benefits of System Mix are; retained digester volume and minimal settlement, with over 90% being retained during its working life, maximised solids reduction, continuous recirculation during mixing ensures full distribution and breakdown of solids, both mechanically and biologically, retained gas production is maintained to levels seen at system start without drop-off, minimal cleanout costs as the digester can be easily cleaned at minimal cost. And finally, low installation costs as all rotating equipment is externally mounted and internal equipment is easily installed.

For more information on System Mix and Rotamix systems contact;

System Mix Ltd, Sawtry, Huntingdon
Tel: 01487 830123 Fax: 01487 832888

E-mail: sales@thesolidsolution.co.uk Web: www.pandmpumps.co.uk