Swru022008 Bioplex Technologies Feb08

Treating waste naturally



Conventional Anaerobic Digesters

Input 1:20th Digester volume, heated and mixed


Conventional Anaerobic Digesters

• Work well if the feedstock is macerated and/or screened

• However both the capital and running costs may be high

• Problems occur when the waste is unsorted or contains high levels of fibre and grit.

• To overcome silting and blockages the Bioplex digester was developed.


Bioplex Process

Portagester

Heat

The Bioplex process uses as its first stage a modular anaerobic fermenter, which treats organic waste material in less than three days. It uses the process of thermophilic fermentation (the first stage of anaerobic digestion -acid phase hydrolysis) to pasteurise feedstock and naturally separate it into liquid and solid fractions.

The liquid can be used as a liquid fertiliser and/or for second stage anaerobic digestion. The anaerobic digester produces methane rich biogas, which can be used in a boiler or a combined heat and power (CHP) generator to generate electricity and heat.

The solid fraction is relatively odourless and can be safely spread onto farmland or composted.

The composted material is an excellent natural fertiliser and growing medium.


Bioplex Process

The original invention was to eliminate or control the problems of blockages and silting up in conventional anaerobic digesters.

Other benefits were discovered:

• Parallel processing preventing cross-contamination.

• Ease of transport and reduction of materials handling.

• Smaller systems are viable, treat at source.

• Environmental advantages, nitrogen and carbon cycles

• Affordable AD


The Alchemy Project - Devon• The Alchemy Project provides a food waste collection and composting service for 500

people living in Honiton, Dunkeswell and Combe Raleigh.

• Energy is exchanged with a biomass boiler heating system, a biogas fired CHP generator can charge the collection vehicle

• The project shows how organic waste can be dealt with safely, locally and in an environmentally friendly way; it will also result in more local jobs, reduced traffic movements

and lower waste bills! The digester site under construction. July 2006

Kitchen waste - to be digested

After 3 days anaerobic

digestion and 21 days composting

- it’s magic!


HMP Guys Marsh

• To treat catering waste, and use the end product - biofertiliser, within the secure area.

• Process energy is exchanged from wood fired boiler and heating system• The plant operation and gardening using the biofertiliser leads to new jobs and

acquired skills.• Estimated seven year payback period, based on 2007 waste disposal costs.• Helps the site and the service to reduce its carbon footprint.


Fruit and vegetable waste treatment

2. Treatment by thermophilic digestion in

a Portagester

The wastes are chopped to less than 20mm. The packaging enhances the final composting process and the end product.

The treatment of food wastes can meet EU and UK standards for ABPR. The temperature controls pathogens, weed seeds and parasites.

3. The end product after composting and screening

This digested material is a natural slow release fertiliser rich compost. The added fibre helps farmland to resist erosion and flooding.

1. Fruit and vegetable waste as

received


Digestate - Plant Growth Trials


Village - Farm scale

Digester

Community Renewable Energy

CHP Plant

Modular system within polytunnel for solar gain

Designed to use all locally available biofuels


AD using Locally Grown Biofuels

• Maize Silage - Feedstock• 1 MW Anaerobic Digester - CHP Generator. Maize and cattle slurry.


Longstock - Hampshire450 people750 cattle65 horses3000 acres17000 trees


Materials and Energy FlowLongstock Energy

Gas boiler and/or CombinedHeat and Power (CHP) generation

Biogas

Anaerobic DigesterDigestate

Homes, farms and commerce

Compost, fertiliser

Farm animal and horse stable manureCatering and food processing wastesEnergy cropsOrganic fraction of household and trade refuse


The Bonus• Restoring the nitrogen and carbon cycles.

Bioplex

The use of Anaerobic Digestion and Composting is at least Carbon Neutral. Carbon absorption by extra plant growth and replacing fossil fuels and petrochemicals.

Nitrogen cycle restored.

Waste from one source becomes useful for others. Farmland uses recovered fertiliser and fibre.

Farms are good collectors of solar energy. This renewable energy source stored and transported using traditional farm machinery.

Energy recovered and used on site.

Rejuvenates the local economy.

Swru022008 Bioplex Technologies Feb08

Technology

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