The Basics Of The Anaerobic Digestion Process

It is, therefore necessary to contain and treat these wastes so that the treated waste sludge is stable; the offensive odour is removed; the quantity of pathogenic bacteria is reduced; the mass and volume of sludge is reduced and the sludge can be readily dewatered and dried.




Anaerobic digestion is the most common method in use today for treating waste water sludges. Its attractiveness comes from it being a relatively stable process if properly controlled, with low operating costs and the production of a useful by-product, a combustible gas, which can be used as a source of energy.

The advantages of this process:

The organic content of the sludges is significantly reduced by conversion into gaseous end-products; the obnoxious odour of the sludge is removed and the final digested sludge has a characteristic 'tarry' odour; fats and greases are broken down by the process; there is a significant reduction in the quality of pathogenic bacteria; there is a marked chemical change after digestion. The liquid fraction (supernatant) contains increased levels of ammonia as a result of the breakdown of organic nitrogen (proteins). This makes the digested sludge liquor potentially suitable for agricultural use; the biogas that is formed is a mixture of carbon dioxide (CO2) and methane (CH4) that can be used for digester heating or to generate power.

The disadvantages of this process:

A relatively high initial capital cost is involved, which tends to limit the process to medium to large size waste water works. The slow rate of bacterial growth requires long periods of time for start-up and limits the flexibility of the process to adjust to changing feed loads, temperatures and other environmental conditions. The process is prone to upsets if not regularly monitored and if corrective action is not taken in time.

Anaerobic digestion is a multi-stage biological waste treatment process whereby bacteria, in the absence of oxygen, decompose organic matter to carbon dioxide, methane and water. In this way, the waste sludge is stabilised and the obnoxious odour is removed. The process can, however be described adequately and simply as occurring in two stages, involving two different types of bacteria. The first stage, the organic material present in the feed sludge is converted into organic acids (also called volatile fatty acids) by acid forming bacteria. In the second stage, these organic acids serve as the substrate (food) for the strictly anaerobic methane-producing bacteria, which converts the acids into methane and carbon dioxide. The end result of the process is a well-established sludge in which 40 to 60% of the volatile solids are destroyed. Finally, a combustible gas consisting of 60 to 75% methane and the remainder largely being carbon dioxide.

The digestion process is continuous. Fresh feed sludge must be added continuously or at frequent intervals. The gas formed during digestion is removed continuously. In high-rate digestion, stabilised sludge is displaced from the digester during feeding. In low-rate digestion, sludge 'supernatant' is normally removed as the feed sludge is added, stabilised sludge is removed at less frequent intervals.

It is essential that the organic acids formed in the first stage of the waste treatment process are converted to methane at the same rate at which they are formed. If not, they accumulate and ultimately lower the pH, leading to inhibition of the second stage of the digestion process and digester failure. Temperature must be maintained within certain ranges - heating increases the activity of the anaerobic bacteria reducing the required digestion time. A pH of 7,0 to 7,5 is recommended to encourage the methane-producing stage. A correctly operating digester will have sufficient buffer capacity (alkalinity) introduced from the breakdown of organic matter.

Michael Russell

Your Independent guide to Waste Treatments [http://waste-treatments.com]

Government to encourage anaerobic digestion projects - Guttridge

The government has pledged to encourage farmers to invest in anaerobic digestion projects, it has been revealed.



Junior DEFRA minister Lord Henley said he was in talks with the Department for Energy and Climate Change (DECC) to help improve Feed-in Tariff rates which are rewarded to those who set up renewable energy programmes.

Speaking at the Northern Farming Conference today (October 15th), he said: "We want to do what we can. That obviously will in due course with DECC mean looking at feed-in tariffs and a whole range of other things.

"We have given a commitment that we will encourage anaerobic digestion."

Lord Henley also claimed the technology can offer farmers a wide range of benefits other than energy production.

In addition to reducing the amount of waste which is sent to the landfill, the bi-product of the anaerobic digestion process can be used as a fertiliser for crops.

Typical Guttridge equipment used in the anaerobic digestion industry includes; elevators – bucket elevators – valves
James Smith 

View the original article here

Distillery secures £3m green loan - BBC News

29 October 2010 Last updated at 17:22  The firm hopes to generate 33% of its energy needs from renewable sources An Edinburgh-based distillery has secured a £3m loan to develop an ambitious green business strategy.




North British Distillery will use the cash to part-fund a three-year £9m investment programme which could generate 33% of its energy needs from renewable sources.

The firm hopes to save between 9,000 and 10,000 tonnes of carbon dioxide emissions annually from the programme.

The £3m loan was provided by Lloyds Banking Group.

The programme includes the installation of a biogas boiler and gas engine that will enable North British to generate its own electricity via anaerobic digestion of its distillate residues.

David Rae, managing director of North British, said: "Our sustainable business strategy will enable North British to make savings in terms of energy costs whilst at the same time significantly reducing the environmental impact of our production process."

The distillery, which has been based in Edinburgh's West End since 1885, already recycles residual low-grade waste heat to heat classrooms at nearby Tynecastle High School.

The firm said the supply enabled the school to make significant energy savings and reduce its own carbon dioxide emissions by 500 tonnes per year.

Most the firm's whisky spirit is sold to other companies for blending purposes, with Famous Grouse, Johnnie Walker Black Label and J&B Rare among its customers.

View the original article here

Anaerobic Digestion in the US "The Time is Right" - Waste Management World

28 October 2010

According to the EPA, the Unites States generate over 30 million tons (27.2 million tonnes) of food waste every year, and recycles less than 3%.

As anaerobic bacteria digest our trash, they release carbon dioxide and methane gas, both of which seep out of the soil and into the air. As a result, landfills are one of the largest producers of methane, which has been proven to be a leading cause of global warming.

It takes an average of 30 years for organic waste to break down into stable compounds in your average landfill, in comparison, a well run composter will complete the job in as little as three weeks.

Brian Dick, CEO of Quest Recycling Services LLC and Matt Hedrick, EVP of Quest Recycling Services LLC were keynote speakers at Biocycle Tenth Annual Renewable Energy From Organics Recycling Conference in Des Moines, IA this month.

Dick and Hedrick encouraged conference participants to jump on the waste to energy revolution and build additional outlets to process organics into high value end products such as energy and compost.

"The time is right" said Dick. "There are less than 200 operating anaerobic digesters in the United States currently and only a select few of those have the ability to process food waste. In contrast, Europe has thousands that have been successful for many years producing green power from food waste. The time to invest in this technology is now."

"We are excited to be in the fore front of this exciting emerging business that can reduce the amount of food waste in our landfills and provide a much need green power source", said Matt Hedrick.

View the original article here

United Ethanol to install anaerobic digester

A $6.75 million project to install an anaerobic digester at a 50 MMgy ethanol plant in Milton, Wis., will begin in a few weeks. United Ethanol LLC will complete the project with the help of $2.25 million in state energy program funds.

It's a way to extract a little more value out of our inputs, the corn, and make the plant greener and more energy efficient, said Alan Jentz, United Cooperative and United Ethanol vice president of grain operations and risk management.




On Oct. 21, Wisconsin Gov. Jim Doyle announced $2.95 million in funding for three southern Wisconsin companies, including United Ethanol. The money comes from Wisconsin?s economic development tax credits and energy program, which is funded through the American Recovery and Reinvestment Act.

The other two projects were $250,000 in tax credits for Standard Process Inc., a whole food supplements company, and $450,000 in energy program funds for Idle Free Systems Inc., which sells battery-powered, idle-elimination systems for over-the-road trucks.

In total, more than $55 million in state energy funds from the recovery act are being used in Wisconsin to help manufacturers with energy efficiency and renewable energy projects. According to the governor's office, Wisconsin is the only state using 100 percent of these funds for these types of projects. In August, Ace Ethanol LLC received $595,000 in funding from the same program for heat exchange equipment.

United Ethanol's anaerobic digester will utilize a portion of the plant's thin stillage to create methane, which will help reduce natural gas use at the plant by up to 25 percent. The project will have an estimated four-year payback, Jentz said.

The project has multiple benefits, including reducing the plant's carbon footprint. The anaerobic digester is also expected to reduce the number of fermentation solids that have to be recycled, reduce fermentation inhibitors, reduce evaporator bottlenecks and eliminate syrup load-out, Jentz said.

Technology provider Eisenmann Corp. will install the digester. The project should take about a year to complete. We hope to get that under way here in the next few weeks, so hopefully it will be online by this time next year,? he said.

Anaerobic digestion isn?t the only technology upgrade project United Ethanol has on its plate. David Cramer, president and CEO, mentioned three projects in the company's August newsletter. The company is working to tie in the CO2 scrubber stack and process vent gas scrubber stack into the regenerative thermal oxidizer for odor control.

In addition, it has a license agreement with GreenShift Corp. to use its corn oil extraction technology. United Ethanol has also contracted with Arisdyne Systems Inc. to install controlled flow cavitation, a patented process to reduce particle size, disrupt cell structures and disperse agglomerates for increased ethanol yield.

View the original article here

Government must prioritise food waste for AD - New Energy Focus

Friday 08 October 2010

ADBA claims food waste should be prioritised for AD over incineration and composting

The government must prioritise food waste for anaerobic digestion due to the benefit of energy generation, a renewables trade body has claimed.

In response to the coalition's Waste Review, which closed yesterday (October 7), the Anaerobic Digestion and Biogas Association (ADBA) has called for food waste to go to AD over composting and incineration.

And, it has stressed the need for a massive increase in household food waste collection and is advocating separate collections, where households have a bin reserved for food waste, so that the "valuable" resource can be more easily used for AD.

ADBA notes that the coalition is committed to a ‘huge increase in energy from waste through anaerobic digestion', but claims that the government will fail to achieve this unless the waste is made available for digestion. This will require changes to waste collection, and priority for treatment through AD, it says.

With cuts imminent in this month's Spending Review, ADBA highlights that many local authorities may be considering shelving schemes to segregate food. However, the association claims that while there are short term savings available now, they will lead to much higher costs to the whole community in the medium term, "especially if we do not build an infrastructure to deal with organic waste away from landfill".

According to ADBA, processing waste through AD offers a sustainable solution for landfill waste, with the added benefit of preserving crucial finite nutrients, such as nitrates and phosphorus.

Commenting on the need to secure food waste for AD, ADBA chairman, Lord Redesdale, said:

"The government knows it must act now to meet the UK's responsibilities on climate change.
Committing to AD technology was a good first step, but it must be followed up by the right decisions about how we deal with waste if the industry is to flourish."

"We need to collect food waste and prioritise it for AD, so that it can make the maximum possible contribution to targets for renewable energy, climate change, landfill mitigation and preserving resources such as phosphorus. This review needs to do more than move towards a "zero-waste" economy, it must also ensure we maximise the use of waste as a valuable resource."

The association added that if supported appropriately, AD could meet up to 40% of the UK's target for renewable heat production by 2020.

View the original article here

Prominent UK business group calls for more energy from waste

Launching a new report, Going to waste: Making the case for energy from waste, the leading business group highlighted the important role that energy from waste could play in a broad-based energy mix, which improves energy security.

Technologies include using anaerobic digestion, where biological processes produce bio-gas from waste, and incineration. These provide consistent and reliable power supplies, unaffected by the weather, and are not imported.

With strong leadership from the Government on planning, financing and procurement, the UK could quadruple the proportion of energy it generates from waste from 1.5% to 6% by 2015.

And the CBI warned that unless urgent steps are taken to cut landfill use, the UK will face fines from the European Union of around £182.5m a year.

Neil Bentley, CBI Director of Business Environment, said:

“We cannot continue dumping rubbish in landfill sites. Waste that can’t be recycled could be used to heat homes and produce electricity, as well as improving our energy security.

“Across Europe, generating energy from waste is common and compatible with high levels of recycling.

“The Government needs to encourage the development of more anaerobic digestion and incineration plants, and tackle delays in the planning system.”

The report focuses on the family of energy from waste technologies, which can be broadly divided into biological and thermal types. Anaerobic digestion can be used on-site to produce heat and electricity, or injected into the National Grid after being purified.

Thermal treatments include technologies, such as gasification and pyrolysis, which involve heating waste to produce gas, as well as incineration. The CBI argues that non-recyclable waste should be incinerated, and emphasises that it is cleaner, more efficient, and environmentally sounder than burning fossil fuels or relying on landfill.

Among the CBI’s recommendations for the Government are:

Recognising the important role that energy from waste could play in reducing the UK’s landfill, securing energy supplies and increasing the proportion of renewable sources;Avoiding picking winners from the various energy from waste technologies and allowing the market to decide the most cost effective option;Reassuring the public that delivering more energy from waste is compatible with high levels of recycling and that new plants are clean and safe.

Echoing her support for the report, Gaynor Hartnell, Chief Executive of the UK Renewable Energy Association (REA) said,

“The Government has already said it wants to encourage Energy from Waste, and it would do well to heed the CBI’s recommendations. Most of the energy content of our household waste is renewable, yet often projects are dogged by overly complex and unnecessary regulation, which prevents them from getting the rewards they are entitled to for generating green energy. A healthy dose of pragmatism would be in everyone’s interests and would enable one of the cheapest forms of green energy to play its part in meeting the UK’s renewables target.”

View the original article here

UK brewery embraces anaerobic digestion - Guttridge

Rapid growth of the anaerobic digestion sector has been highlighted by the adoption of the technology by a Suffolk brewery.

Adnams Brewery has introduced anaerobic digestors to its Southwold plant to turn waste from the site and surrounding companies into biogas for the national grid.

Climate change minister Greg Barker expressed his delight at the move as it follows the announcement that Thames Water and British Gas will turn sewage into biogas.

He said: "This has been an excellent week for progress in renewable energy. As well as the waste from making beer, Adnams Bio Energy is taking in food waste from local businesses large and small."
Adnams claimed that the waste by-products generated from brewing 600 pints of beer could generate enough gas for one home a day.

In addition to producing power for the local community, the gas will also be used to power the Southwold brewery and run its fleet of vehicles.



Typical  uses in the anaerobic digestion industry includes; elevators – bucket elevators – valves
James Smith

View the original article here

Brewery AD plant delivers renewable gas to grid - New Energy Focus

Tuesday 12 October 2010

Adnams Bio Energy has injected the first renewable gas from brewery waste to the National Grid from its AD facility in Suffolk

An anaerobic digestion facility in Suffolk has become the first plant in the UK to produce renewable gas from brewery and local food waste for export to the National Grid, and only the second AD plant in the UK to inject biomethane into the gas network.

Adnams Bio Energy delivered the first biomethane late last week (October 8) from its AD plant in Southwold; just three days after Didcot sewage works in Oxfordshire celebrated being the first project to send renewable gas produced from sewage to the grid (see this NewEnergyFocus.com story).

In partnership with British Gas and National Grid, Adnams Bio Energy says it will generate up to 4.8 million kWh per year, which it claims is enough to heat around 235 family homes for a year.

In the future, the facility will also produce enough renewable gas to power the Adnams brewery and run its fleet of lorries while still leaving up to 60% of the output for injection into the National Grid.

Waitrose is the first business to sign up to supply waste to the facility and has committed to sending food waste from seven of its nearby branches, along with a John Lewis.

Commenting on the project, Mike Walters, recycling and waste operations manager for Waitrose and John Lewis, said: "We are delighted to be the first retailer to become involved with Adnams Bio Energy in this exciting project.

He added: "This project is unique as it produces renewable gas from brewery and food waste for injection into the national gas grid rather than to generate electricity."

The Adnams Bio Energy plant consists of three digesters, which are sealed vessels in which naturally-occurring bacteria act without oxygen to break down up to 12,500 tonnes of organic waste each year. The result is the production of renewable gas as well as a liquid organic fertiliser.

In addition, following an agreement with British Gas, Adnams Bio Energy has deployed solar thermal panels and will shortly install photovoltaic cells to generate renewable electricity for the plant.
The deal will ensure that all of the site, including the Adnams Distribution Centre, will be using renewable energy generated on-site with some surplus energy available for export.

Chief Executive of Adnams, Andy Wood, commented: "We are delighted that Adnams Bio Energy is located on the site of our eco-distribution centre. For a number of years now, Adnams has been investing in ways to reduce our impact on the environment. The reality of being able to convert our own brewing waste and local food waste to power Adnams' brewery and vehicles, as well as the wider community is very exciting.

"The industrial ecology cycle is completed when the fertiliser produced from the anaerobic digestion process can be used on farmland to grow barley for Adnams beer. This facility will have a major impact on the reduction of carbon emissions in the region and the production of renewable energy. The food waste would otherwise be destined for landfill, but processing it through the digester will save an estimated 50,000 tonnes of CO2 equivalents from landfill."

Construction of the AD plant concluded in July (see this NewEnergyFocus.com story).

View the original article here

PROjEN Joins Forces with Doctor Les Gornall in Anaerobic Digestion and Waste ... - Online PR News (press release)

Specialist Engineering Project Management company PROjEN PLC, based in Preston Brook, Cheshire has formed an Alliance with Doctor Les Gornall who is widely regarded as the UK?s leading expert in Anaerobic Digestion and Waste Water Treatment.

Online PR News – 11-October-2010 – Specialist Engineering Project Management company PROjEN PLC, based in Preston Brook, Cheshire has formed an Alliance with Doctor Les Gornall who is widely regarded as the UK?s leading expert in Anaerobic Digestion and Waste Water Treatment. This partnership gives even greater weight to PROjEN?s service offering and demonstrates the company?s commitment in becoming the UK?s leading supplier in all aspects of waste management, including de-packaging, anaerobic digestion, CHP and conversion of waste heat to electricity.

Dr Gornall has over 30 years experience of building, operating, designing and commissioning anaerobic digesters and waste water treatment plants. He has become an internationally recognised environmental consultant who has extensive experience in waste and biogas issues across the world. He has written many papers for technical magazines and is often quoted by his pseudonym ?Dr Sludge?.

PROjEN have expanded their service offering into a number of niche areas such as helping companies to reduce their energy costs and meet legislative compliance issues including DSEAR, IPPC and post Buncefield Requirements. These new services have been driven by clients and in recent times many in the waste industry have been pushing for a combination of both the theoretical and practical aspects of waste management. PROjEN?s Managing Director, Martin Seabrook comments:

?PROjEN?s strength is that when we offer a service we ensure we can add value to the client. We recognise that no one individual or company has all the answers and by working with like minded associates we can each focus on our own strengths. Through Les? extensive knowledge of the waste market and our own award winning history in project and construction management we feel we are able to offer our clients a much stronger package than our competitors?.

In addition to working with Dr Gornall PROjEN have also renewed their distributor agreement with FreePower - this product generates electricity from waste heat and will become a major talking point this year in both waste and industrial applications. PROjEN have also formed an alliance with Axion Consulting ? process experts in the field of waste and recycling.

View the original article here

USDA tours 300kW farm biogas facility in Vermont

The Chaput Family Farm in North Troy has installed a 300-kilowatt anaerobic digestion facility to turn organic materials like manure into biogas for use generating electricity.

Electricity produced by the project will meet all of the farm’s needs, with excess power sold to the local utility. The facility will also provide heat and hot water for the dairy herd.

As well as producing clean energy, the facility will also produce a solid residue that provides an effective alternative to fertilizer.

The Chaput’s digester is the first facility on Vermont’s Standard Offer Program, which provides the farm a fixed price of 16 cents per kilowatt hour for its power output over the next 20 years. The farm will also receive a renewable energy credit of 4 cents per kWh for the next five years through Central Vermont Power Service’s “Cow Power Program.”

The farm will produce all of its on-farm electricity, heat, hot water and bedding for the cows. It will sell the excess power to the local utility. The excess bedding will be sold to local farms.

Anaerobic digestion involves microbes feeding on liquidized organic material within large tanks, and in the process giving off a methane-rich biogas that can be collected and combusted to produce electricity.

The Chaput Family, which owns four farms, built the digester to handle manure from 1,600 mature cows and young stock.

The digester project in North Troy was given financial assistance by the USDA through its Rural Energy for America Program, authorized by the 2008 Farm Bill.

The REAP program offers development assistance, grants for energy audits and funds to help agricultural producers and rural small businesses purchase and install renewable energy systems and make energy efficiency improvements.

USDA Rural Development Vermont State Director Molly Lambert was joined on the tour of the dairy farm by Rural Business-Cooperative Service Administrator Judith Canales and Farm Service Agency State Executive Director Robert Paquin.

“This project highlights the way USDA agencies are working together to help rural farmers and businesses,” Ms Canales said. “Supporting our farmers in projects like this is good for them, good for the environment, and good for businesses and residents throughout the community.”

The federal Natural Resources Conservation Service provides technical and financial assistance to producers for anaerobic digesters through the Environmental Quality Incentives Program (EQIP), and this year funded four new digesters in Vermont.

The NRCS also offers technical and financial help for other aspects of anaerobic digestion projects.

Commenting on the North Troy facility, NRCS State Conservationist Vicky Drew said: “In addition to reducing greenhouse gas emissions through the collection of methane, the digester will also reduce energy needed to produce and haul bedding to the farm by recycling the manure onsite into a dry bedding material for the cows, creating a closed-loop system.”

The USDA’s Farm Service Agency (FSA) has now established a new conservation loan program that can be used to finance anaerobic digestion projects approved by the NRCS. Up to $300,000 in loans and up to $1.12 million in loan guarantees are available, and can be used along with other grants and loans.

View the original article here

Optimise the Efficiency of Anaerobic Digestion - International Environmental Technology

A high-speed, high-temperature HT200S laboratory digester from HACH LANGE has helped one of Europe’s largest recycled packaging companies to cut analysis times by 75%.

This process has also enabled Smurfit Kappa SSK to optimise the efficiency of the anaerobic digestion to generate quality biogas, which helps to recycle the effluent waste produced on site.

By deploying the advanced HT200S, along with a DR2800 VIS Spectrophotometer at its biogas plant, the analysis of nutrient levels ensure that the site’s anaerobic reactor is running effectively, reducing analysis times by 75% as a result.

Prior to analysis in a DR2800, samples are digested in the HT200S, with digestion times for Nitrogen, Phosphate and Chemical Oxygen Demand (COD), which previously took two hours, now taking just 15 minutes.

Ciaran Conroy, from Smurfit Kappa SSK, explained that the HT200S has radically altered nutrient analysis at the plant. He said: “The HT200S allows us to be more reactive to alterations in the process, as a result of the speed with which we are now able to take measurements. The speed of digestion is complimented by the fact that the HT200S cools the samples so that they can be transferred to the spectrophotometer immediately.”

“The easy identification of COD and Volatile Fatty Acids (VFA) in the biogas reactor is just one example of this, enabling us to react in a matter of minutes, resulting in less time spent on maintaining the biogas reactor.”

The HT200S can also digest samples prior to analysis for Chromium, Tin, Silver and Total Organic Carbon (TOC).

The portable HT200S can provide numerous benefits for virtually every industry where COD, nitrogen, phosphate or metals analysis has to take place, saving significant maintenance time and costs in the process.

For a brochure, please contact sarah.blayds@hach-lange.co.uk

View the original article here

Chickens to power Gloucestershire town - Building.co.uk

First homes to receive power generated from chicken litter after biogas plant opens in November

Cirencester in Gloucestershire is to become one of the first towns in the UK to benefit from power generated using chicken litter.




The power plant which is due to open in November is being built on a farm to the south of the market town.

It will take animal waste as well as corn, wheat and grass from local farms and produce methane-rich biogas via a process of anaerobic digestion.

The gas will be used to power a combined heat and power unit generating around 1MW of electricity, enough to supply 350 homes.

The waste heat will be used for keeping the animal sheds warm, drying grain and local housing. After the biogas is extracted the fibrous material left is spread on the land as fertilizer.

The plant is being supplied by Alfagy who is looking to set up similar facilites throughout the UK.

View the original article here

A Round-Up of the New Anaerobic Digestion Plants in the News - Spring to Summer 2010 UK/Europe

Converting organic waste materials into renewable energy is an essential component of the EU countries both to meet national commitments to renewables EU targets, and indirectly to achieve zero food and packaging to landfill. So, how is the construction and commissioning of new AD plants proceeding, which will contribute to this?

Here is a summary of a few projects recently reported.

Cambi has announced that it will be supplying the technology for a new sludge treatment anaerobic-digestion plant in Drammen, Norway using their thermal hydrolysis process to optimize conversion. This will use feed stock sludge and waste and the contract is worth about 12M USD.

Vertal appears to be using Anaerobic Digestion as a component of its process mix, which includes composting and pasteurisation of food waste. This award winning company accomplishes this, we are informed, entirely through self heating, harnessing the energy released during digestion to carry out the pasteurisation.

A WRAP (Waste Resources Action Programme), part UK Government Funded, 3M GBP anaerobic digestion plant has opened on a Staffordshire (UK) Farm. This plant will supply 1.3MW of renewable energy to the national grid, with most of the energy being derived from source segregated food waste. It will process 15,000 tonnes of waste annually. Full operational output is planned for Autumn 2010.

Xergi's AD plant in Ayrshire, Scotland is moving ahead, and is expected to be operating by early 2011.  The purchaser's Chief Executive has plans to extend the pant to include connection to the gas distribution network. The Ayrshire plant will become Xergi's second UK plant, with their first UK plant located near Boston, Lincolnshire, UK.

AD plants succeed or fail on the ability to mix feedstock and then again within the reactor. System Mix is reported to be providing mixing expertise to Welsh Water, and other clients for their digesters. One of the mixing systems in use will be a drop-in lance type system.

Jenbach (Austria) also announced in July that the troducer of Baby Nutrition Products would soon be saving CO2 based on the special “Green Tariff” available to anaerobic digestion plant generated electricity available at the plant's location.

In this project cow manure is being converted to energy at the first biogas co-generation plant in the Ukraine. The facility, which is powered by 4,000 cows and a GE (NYSE: GE) Jenbacher gas engine, has recently completed nine months of successful operation at the Ukrainian Milk Company Ltd., located near Kiev.

The excess power produced at the plant is being sold to the grid. The Ukrainian Milk Company, which produces milk for baby nutrition products, received the license for selling power to the grid based on the “green” tariff, which is being approved by Ukraine authorities. According to the law, the “green” tariff is “a special tariff for electricity generated at the power plants with use of alternative energy sources.”

The new combined heat and power (CHP) plant is powered by a GE JMC 312 containerized co-generation model gas engine and is able to substitute the equivalent of 1.2 million cubic meters of natural gas annually and, therefore, is projected to reduce the equivalent of 18,000 metric tons of CO2. Once converted into biogas, the manure from the cows produces 625 kW of electricity and 686 kW of thermal output.

This is GE’s first order from the biogas plant construction company ZORG. The unit was sold to ZORG through GE’s distributor and service provider in the Ukraine, SINAPSE. We hope that you found this round-up of the new Anaerobic Digestion Plants in the News from spring to summer 2010 interesting.

More about the Ukraine Plant at Ukraine Milk Company Powered by 4,000 Cows and GE Biogas Engine.

Danish Company to Build Anaerobic Digestion Plant in N Ayrshire Scotland

Denmark’s market leading supplier of AD technology is to build a large AD plant in Scotland. The agreement which amounts to approximately 8.0 million Euros has been entered into with one of the largest energy companies in the UK, Scottish and Southern Energy.

The Scottish AD plant will be built at Barkip, North Ayrshire. It is expected to be operational for energy production in early 2011 and will contribute to achieving Scottish targets for CO2 reduction. The plant will be capable of processing 80,000 tons of organic waste annually, producing 2MW of renewable electricity. The plant will be the first for both Xergi and SSE in Scotland.

The entire plant will be delivered by Xergi and will convert the organic waste into renewable energy in the form of methane gas and nitrogenous organic fertiliser.

The plant consists of reception facilities, a fully automatic feeding system capable of handling many different types of organic waste, anaerobic digesters with a unique stirring system for the production of methane, a CHP (combined heat and power) unit producing power and heat, and storage tanks for the fertiliser.

SSE Chief Executive Ian Marchant said:

“Biogas has the potential to be one of the most important new generation renewable and sustainable energy solutions available to us, capturing the energy contained in waste. SSE is excited about entering the biogas market which we believe offers opportunities beyond on-site electricity generation to include connections to the gas distribution network in the future. This new project will enable SSE to gain experience in owning and operating this technology so we are well placed to bring that knowledge to future projects in Scotland.”

For more information visit the Xergi web site.

Large Ener-G AD Plant Biogas Cogeneration System Gets Hungary on Map of AD User's

ENER-G is the company playing a big part in great Hungarian wastewater scheme.

One of Europe's most bold biogas from wastewater projects has been switched on in Budapest by ENER-G.

The UK clean technology company's Hungarian subsidiary ENER-G Energia Technologia Zrt. Has designed and constructed this 2.6 million renewable power centre at the Budapest wastewater treatment plant in Csepel.

It will be part of the Living Danube programme, which is Europe's biggest environmental investment currently in development.

ENER-G has installed a 4.5 MWe biogas cogeneration system, along with 3 2.5MW Loos boilers for further hot water generation using natural gas, or biogas. The company also manages the operations and upkeep services. The eco-friendly energy centre will form part of a biological treatment facility covering 70,000m on a twenty-nine hectare site at Csepel Island.

The plant will increase the quantity of biologically treated wastewater in Budapest to 95% by 2010 treating a standard 350,000 m3 / day waste water from almost all of Buda and part of Pest, serving roughly 1,000,000 folks.

The development of the plant took more than 2 years and cost almost half a billion EU Bucks. Financially the project has been backed by the ECU , the Hungarian state and Budapest municipality.

It'll meet high environmental standards, achieving nought emissions and no odours outside of the site borders.

It'll supply up to 4.5MWe of renewable (replaceable) electricity to the site which means that it gives over 50% of the plant's total electricity consumption. This is comparable in output of eight giant air turbines. ]

The maximum 8.5MW heat generated by the mixed heat and power ( CHP ) unit is exploited in the digester process consuming 563m3 / h biogas per unit. The Budapest wastewater treatment plant is a clear illustration of how effective anaerobic digestion is as a commercial and environmental solution for sizeable projects like this, related Balazs Marialigeti, Director of ENER-G.

It is very fulfilling to be concerned in this revolutionary venture and we are looking forward enthusiastically to full commissioning in Sep 2010. Anaerobic digestion ( AD ) transforms organic waste material into energy and is a definite winning technology that delivers important commercial benefits, while helping to reduce carbon dioxide emissions.

Digestion plants produce a biogas that has high methane content of 50-70 percent. This otherwise environmentally damaging gas is a rich fuel that may drive a CHP unit to generate both heat and electricity.

The heat may be employed in the digestion plant alongside for heating in close by buildings, while the replaceable electricity can be sold at premium rates.

ENER-G has substantial experience of building, operating and financing major biogas projects across Europe and the company is expanding its team of specialist engineers to meet increasing demand for methane-rich biogas projects , for example AD.

For more information visit ENER-G's web site.

Did You Know that Thames Water Burns Its Sludge (it Also Digests It Too)

Thames Water achieved a saving of £15m on its electricity bill in 2008/9 by generating its own renewable power from its 13.6 million customer created sludge.

Britain's largest water and sewerage company generated a 14 per cent of its power needs from a combination of burning sewage sludge at some locations, and anaerobically digesting it at others, and then burning the methane derived from it.
Thames Water's Climate Change Strategy Manager, Dr Keith Colquhoun, is quoted as saying that their investment in renewable energy plants has been

"good news because we now treat 2.8 billion litres of sewage every day at our 349 sewage works. The solids in sewage have a high calorific content that we use to generate electricity.

"And this isn't a gimmick: as well as helping us to be more sustainable as a company, it also saves money - £15m less spent on energy last year alone, saving money for customers."

"Our goal is to cut greenhouse emissions by 20 per cent on 1990 levels by 2020 - that's about 200,000 tonnes less CO2. By using sludge derived power and other renewable energy sources, we're making significant progress towards this target after cutting emissions by five per cent in the past two years, despite grid energy becoming more carbon-intensive.

"Delegates at the Copenhagen Climate Change Summit must face the fact that combating climate change is no longer about talk. It's about all of us taking action - and in our case, that includes sludge power."

Thames Water - which has the largest renewable electricity generation capacity inside the M25 motorway ring, excluding the commercial electricity generators - uses two methods to generate power from sewage:

1. Thermal destruction with energy recovery, where sewage sludge, which is the solid content of the sewage dried into blocks of 'poo cake', is burned to generate power; and
2. Anaerobic digestion, or (with) CHP (combined heat and power) generation, which is where methane derived from sewage sludge is burned to created heat, which in turn generates power.

The following Thames Water sewage works have AD/CHP plants: Maple Lodge (Rickmansworth), Mogden (Isleworth), Rye Meads (Herts), Deephams (Edmonton), Oxford, Reading, Long Reach (Dartford), Slough, Hogsmill (Kingston), Beddington (Surrey), Swindon, Bishops Stortford, Banbury, Aylesbury, Basingstoke, Bracknell, Camberley, Crawley, East Hyde (Luton) and Wargrave (Berks).

And the following two works use thermal destruction:

Beckton, in East London north of the River Thames, Europe's largest sewage works, which treats about 3.5 million people's waste every day; and Crossness, in East London south of the river, which treats the human equivalent of 2 million people's waste.

After it has been used to generate electricity, Thames Water then offers the remaining sewage sludge to farmers to use as fertiliser, or to developers as landscaping material or soil improver. In 2008/09 the firm put 100 per cent of its sewage sludge to beneficial use, sending none of it to landfill and as a result saving millions of pounds in UK landfill tax.

Further details about using sludge to generate power and Thames Water's 100 % win-win utilisation of sludge for renewable energy production can be found in the company's Corporate Responsibility Report

TESCO Shopping Complex to be Powered by Food Using Anaerobic Digestion

The power of food

Supermarket giant TESCO'S new distribution centre in Widnes is to be completely powered by renewable energy generated from food waste, they have announced.

It has joined with with transport company Stobart Croup, and food waste recycling experts the PDM Croup in a move that will see the new shopping centre take its renewable energy from PDM's combined heat and power (CHP) plant that turns 230,000 tonnes of food waste, including Tesco's unwanted, into green renewable heat and electricity. The retailing company is already working with PDM which recycles all Tesco's meat waste at present.

There are no losses in the cable route either as the power is sent via their own cable link which provides renewable energy direct from the CHP plant to the neighbouring distribution centre.

Tesco has leased the new 528,000 sq.ft. distribution centre, which will see its first customers this summer, to provide increased capacity to service its growing network of stores in the north west of England.

Juliette Bishop, Tesco's corporate affairs manager, said:

"This venture is an ideal example of how sustainability is at the very core of the Tesco business and it's great that we can demonstrate that our food waste is directly providing power back into our operations, helping us to reduce waste going to landfill and our carbon footprint."

Stobart and PDM will work together to offer Stobart's customer-base comprised of predominantly food retailers, a recycling service. The agreement would see food waste taken in return journey loads, on Stobart vehicles, to Widnes.

The Widnes plant recycles more than 230,000 tonnes of biomass fuels a year to generate renewable combined heat and power using biomass-to-energy technology.

The fuel is derived from food and other bio-wastes produced from every stage of the food chain, from farm to dinner plate.

PDM Croup director Robert Ratcliffe explained:

"Using green power is becoming an important objective for many businesses, however it's extremely rare that such power can come directly from anywhere other than the National Grid. This type of closed-loop biomass-to-energy relationship is rare in the UK and it's great that we can work together to not only help bolster green credentials, but also enable Tesco to demonstrate that any food waste it generates is essentially helping to power its own supply chain."

Get Even More from Bio-waste EU Commission Decides

Yet more good news for the Anaerobic Digestion process as this is bound to mean promotion of the use of the process, so here is the full news release:

New EU Commission Strategy Announced to get Even More from Bio-waste

The European Commission today laid out steps to improve the management of bio-waste in the EU and tap into its significant environmental and economic benefits.

Bio-degradable garden, kitchen and food waste accounts for 88 million tonnes of municipal waste each year and has major potential impacts on the environment. But it also has considerable promise as a renewable source of energy and recycled materials.

Today’s Communication promotes actions to unlock this potential by making the best use of existing legislation while giving Member States discretion to choose the options best suited to their individual circumstances. Supporting initiatives at EU level will also be necessary.

Environment Commissioner Janez Potočnik said: "We already have a significant body of legislation governing bio-waste in the EU. But through better implemention and enforcement, we can squeeze even more benefit from bio-waste. This will not only help in the fight against climate change: producing good quality compost and biogas will contribute to healthy soil and slow biodiversity loss."

Bio-waste is an untapped potential

A Commission assessment has identified significant environmental and economic benefits from improved management of bio-waste in the European Union.

Today’s Communication lays out recommendations on the way forward to reap these benefits in full. The most promising approaches include the prevention of bio-waste and biological treatment with the production of compost and biogas.

The main environmental threat from bio-waste is the production of methane, a powerful greenhouse gas 25 times more potent than carbon dioxide. If biological treatment of waste was maximized, the most visible and significant benefit would be avoided greenhouse gas emissions – estimated at around 10 million tonnes of CO2 equivalent in 2020.

About one-third of the EU's 2020 target for renewable energy in transport could be met by using biogas produced from bio-waste, while around 2% of the EU's overall renewable energy target could be met if all bio-waste was turned into energy.

Good quality compost and digestate from anaerobic digestion would improve resource-efficiency by partially replacing non-renewable mineral fertilizers as well as by maintaining the quality of EU soils.

Full implementation of existing policies supported by improved bio-waste management should deliver environmental and economic benefits estimated at between €1.5 and €7 billion, depending on the ambition of recycling and prevention policies.

Priority actions

According to the Commission's analysis there are no policy gaps at EU level that could prevent Member States from taking appropriate action. Progress achieved in several Member States shows that existing waste legislation is an excellent basis for advanced bio-waste management. For this, the available tools need to be used to their full potential and rigorously enforced where necessary in all Member States.

Priority actions include rigorous enforcement of the targets on diverting bio-waste away from landfills, proper application of the waste hierarchy and other provisions of the Waste Framework Directive to introduce separate collection systems as a matter of priority.

Supporting initiatives at EU level – such as developing standards for compost – will be crucial to accelerate progress and ensure a level playing field across the EU. This will involve specific guidance and indicators for bio-waste prevention with possible future binding targets, as well as compost standards and guidelines on the application of life cycle thinking and assessment in the waste sector.

Bio-waste management in the Member States

Member States have vastly diverging national policies for bio-waste management, ranging from little action in some Member States to ambitious policies in others.

The environmental and economic benefits of different treatment methods for bio-waste depend on local conditions such as population density, climate and infrastructure.

Composting and anaerobic digestion offer the most promising environmental and economic options for bio-waste that cannot be prevented. However, an important pre-condition is good quality input to these processes. In the majority of cases this would be best achieved by separate collection of bio-waste.

Highly efficient systems based on separating various streams of bio-waste already exist in Austria, Germany, Luxembourg, Sweden, Belgium, the Netherlands, Cataluña in Spain and certain regions in Italy.

The Communication on bio-waste is available at:

http://ec.europa.eu/environment/waste/compost/index.htm

White Paper on Waste and Climate Change: ISWA Very Positive on Anaerobic Digestion's Role in Reducing Waste Industry Emissions

Here is the AD News' summary of the Most Important Points from the new ISWA "White Paper on Waste and Climate Change", for those interested in Anaerobic Digestion.

The climate change phenomenon, its causes and consequences, is now generally accepted and recognised by the international scientific community, governments, the private sector, NGOs and the general population.

It requires a robust response. Solutions must be found that will mitigate emissions of greenhouse gases and help to adapt to its unavoidable consequences. The complexity of the issue requires the acceptance of a common responsibility from both the public and private sector.

The waste industry occupies a unique position as a potential reducer of greenhouse gas (GHG) emissions. As industries and countries worldwide struggle to address their carbon footprint, waste sector activities represent an opportunity for carbon reduction which has yet to be fully exploited.

The waste sector offers a portfolio of proven, practical and cost effective technologies which can contribute to GHG mitigation. When adapted and deployed according to local traditions and needs, they can help secure significant global GHG emission savings.

The global direct GHG emissions resulting from waste management activities are around 1.3Gt CO2 eq. or approximately 3 – 5% of total anthropogenic emissions in 2005 (IPCC 2007). However, there is now credible evidence that, taking into account associated avoided emissions, the waste sector can completely change this picture.

Through aerobic and anaerobic biological treatment technologies, organic wastes can be recovered and transformed into soil conditioners and fertilisers. These processes reduce GHG emissions by sequestering biogenic carbon in soils, improving soil physical properties, and adding soil nutrients.

The organic component of waste (e.g. paper, cardboard, food waste or garden waste) ranges from 30-70% of total municipal waste production. If collected separately, it can offer a valuable contribution to GHG emissions reduction and soil improvement.

Organics recovery is particularly effective where soil and organic matter are being eroded due to deforestation, cultivation practices, or as a consequence of climate change.

Anaerobic technologies provide an added energy benefit.

Waste offers a significant source of renewable energy. Incineration and other thermal processes for waste-to-energy, landfill gas recovery and utilisation, and use of anaerobic digester biogas can play important roles in reducing fossil fuel consumption and GHG emission.

Accurate measurement and quantification of GHG emissions is vital in order to set and monitor realistic reduction targets at all levels. Current methodologies form a valuable database for assessment of GHG emissions from waste activities, however, improvements are required to adequately represent the full lifecycle of materials and energy.

• IPCC national waste GHG inventory methodologies estimate direct emissions, but do not include indirect emissions and environmental benefits, especially those which impact other sectors.
• Improved, harmonised and transparent approaches for both the direct and indirect emissions associated with waste management activities must be developed to complement existing methodologies.
• More consistent and coordinated data collection is needed to support the improved methodologies and reduce accounting uncertainties.

More about Waste and Climate Change at ISWA.

GWE Biogas Anaerobic Digestion Plant Will Help Businesses Meet Their Obligations

This is what GWE Biogas are saying, and we have no doubt with good reason, while building their new Anaerobic Digestion plant at Sandhill, Driffield, East Yorkshire.

The following has been adapted from their March newsletter:

GWE report being delighted to see that even before operations have begun the plant is being recognised as being highly innovative by external organisations. As a part of the Environmental Transformation Fund programme administered by WRAP on behalf of DEFRA and DECC, GWE’s plant will help the UK deliver an increase in the generation of renewable energy, a reduction in the waste sent to landfill and a reduction in greenhouse gas emissions.

They explain that their new biogas methane plant will help businesses meet their obligations, because whilst many businesses know that they need to play a part in cutting greenhouse gases, taking action to is not always a simple matter.

However, when the new Sandhill anaerobic digestion facility near Driffield comes online later this year, businesses and organisations who separately collect food waste will be able to make a difference by simply choosing to send their waste to GWE Biogas.

By converting food waste into a stream of biogas, that can then be used to generate either renewable electricity or be used directly as a renewable fuel, GWE Biogas can guarantee customers that they are maximising environmental benefit and reducing greenhouse gas emissions by the maximum amount possible.

In addition, this will often be for less than it costs to send waste to landfill.

Whilst composting processes stop the direct emission of harmful landfill gas to the atmosphere, formed by the decomposition of food waste and other organic materials, this is where the benefit stops.

The anaerobic digestion of food waste has the added value step of producing renewable energy that can displace energy produced from fossil sources.

Each kilowatt hour of grid based electricity produced results in around 500 grams of carbon dioxide emissions and so each kilowatt hour of electricity produced by the
anaerobic digestion process saves 500 grams of carbon emissions.

Visit GWE Biogas at their web site www.gwebiogas.co.uk .

An Anaerobic Digestion Scene Setter and Summary of AD Opportunities

With an ever growing list of subscribers to this blog it is a continuing challenge to provide basic information on the development of biogas production for our latest subscribers.

That is why today I bring you a link to a web site page written by Dr Michael Gell, which in my view, although put up about a year ago, still provides a pretty fair picture of AD technology and market developments plus opportunities.

Here's the introduction to the article, and if you want more, the link is at the bottom of this post:

Supermarkets are trialling anaerobic digestion as a way to generate energy and minimise their waste, and soon the biological process could have a far wider reaching application

With a spate of announcements on anaerobic digestion (AD) – from supermarkets using the biological process to handle their organic waste to the building of a national AD biogas network - something seems to be exercising decision makers. Are those bacteria that digest food waste at last going to be harnessed to their full potential? Dr Michael Gell examines the potential for AD to kick-start the building of an integrated biowaste infrastructure and to become one of the star technologies feeding energy into a renewables supergrid.

Topics discussed are:

What is Anaerobic Digestion?
How does AD work?
AD as a production process
How widely is AD being used?
Recognising the potential for AD
Turning waste into useful products
What are the environmental benefits of AD?
Economic opportunities with AD
What is driving the surge in interest in AD?
Who are the key stakeholders for a national AD infrastructure?
Carbon footprints in the food waste chain
What are the supermarkets doing?
Is AD commercially feasible?
What are the prospects for a renewable gas network?
What innovations might we expect with AD technology?

Go to ClimateChangeCorp.com's AD Page.

Make Digestate from Source Segregated Biowastes Using PAS110 and it isn't a Waste Material

The new PAS110 protocol is good news for those Anaerobic Digestion Plant operators that utilize a solely green waste (eg source segregated garden waste) feed source because UK regulators have been confirming this month that within a set of specific criteria they will not apply formal waste regulatory controls to these digestates.

The suitable waste input list includes:

• Source segregated biowastes
• Biodegradable non-waste materials
• Allows for packaged biowaste.

(See Nina Sweet link below)

This is great news. It means that it is then much easier to use this material as for example a fertilizer, and spread it on land.

When any material is designated as a waste, it is not only the additional burden of the regulatory measures themselves which are essential for compliance with the Waste Regulations. It is also the cost of additional record keeping and monitoring, plus the Waste License fees, which are a big negative for potential users and sellers as well.

I imagine that it will especially help farmers who take in green waste from the local council and wish to produce biogas from it in on-farm digestors.

PAS110 is known as the Quality Protocol for Anaerobic Digestate and it was published in its final form January 2009. In the last few weeks it has received approval by the European Commission.

This reclassification of this type of digestate as a product and not a waste, will no doubt prompt a new generation of biogas digesters of the best kind, using green waste biomass rather than food crops.

The BSI PAS 110 safety standard is however, not entirely free of constraints and there are costs in the necessary monitoring required by the standard to assure the high quality of digestate produced from these biogas digesters.

More information is available at:

The WRAP Anaerobic Digestion PAS110 Guide download page

SEPA Waste regulation web site (Scotland)

AD Centre Wales PAS110 features Nina Sweet's document

Let's Recycle's Anaerobic Digestion page (scroll to the bottom)

Renewable Energy Association UK REA Names Gaynor Hartnell as Chief Executive

The Renewable Energy Association is the largest trade body for renewable energy in the UK and represents all renewable energy technologies.  Gaynor Hartnell, who was formerly Director of Policy at the Association, has just been appointed as Chief Executive.

Mark Candlish, Chair of the REA’s board of directors said;

REA Press release
2010/02/23 16:00:37.374 GMT

“I am delighted to announce the appointment of Gaynor Hartnell as the Association’s new Chief Executive.  Gaynor has been key to the success of the Association since it was founded in 2001, and in the last 10 months has proved herself the natural successor to Philip Wolfe in her interim role as Policy Director.  Not only does Gaynor have an excellent grasp of renewable policy issues, but she is also well respected by industry and government and is an excellent champion for the industry.”

Gaynor Hartnell said;

“I am very much looking forward to leading the Association and building up its membership base.  These are exciting times for the sector.  This has to be the decade of delivery for renewables, the time when deployment ramps up tenfold.  New players will enter and transform the energy market, with the introduction of feed in tariffs this April.  A year later we will finally have financial incentives operating across the whole spectrum of energy applications - power, transport fuels, heat and green gas.  Renewables can then play a full role, with a diverse range of complementary technologies, which together bring wide-ranging benefits.”

The Association will shortly move into much larger offices in the Capital Tower, next to Waterloo Station.  This will facilitate the expansion of services needed to support the rapidly growing renewables industry with information services, proactive policy development, training and networking events.

Paul Thompson has been promoted to Head of Policy.  Paul joined the REA in 2008 to work on transport fuels, and over the past few months has extended his remit to cover the Renewable Heat Incentive and Renewables Obligation.

Prospects for Anaerobic Digestion Remain Positive Despite Failure of Copenhagen Climate Summit

A recent article in the New Civil Engineer magazine, the magazine of the UK’s Institution of Civil Engineers, discusses how now after the failure of the Copenhagen Climate Summit it will be possible to rise to the challenge of complying with UK carbon reduction pledges.

You only have to read the following paragraphs from the above NCE article to realise the enormity of the task ahead even for just the water industry:

The UK government has pledged that emissions of greenhouse gases will be cut by 80% C02 equivalent - measured against 1990 levels - within the next 40 years.

Yet over the same time Britain's population is expected to grow by anywhere from 15% to 30%, per capita water use is rising and it is likely the [water] industry will be required to meet higher quality and environmental standards - all driving up energy consumption. How are companies going to square the circle?

As readers of my Anaerobic Digestion blog, I am sure that you will not want me to dwell upon the negatives, such as the fact that so far almost all we have seen so far has been rhetoric, while UK carbon emissions have continued to rise.

This is despite that fact that we have exported so much of our emissions as our manufacturing industry has declined, in favour of imports. Even the water industry admits to a 10% rise in carbon emissions since 2000.

So, where will we find the huge cuts needed? We will clearly have to go far beyond efficiency savings which might optimistically, for example, within the water industry provide 30% to 45% savings given the right (high) levels of investment needed.

Opportunities to cut carbon further do undoubtedly exist, and to quote the 14 January 2010 NCE article, for the UK Water Industry example, these might comprise:

• demand reduction
• improved design
• adoption of new technologies
• operational improvements
• better management of catchments and drainage systems and
• wider use of renewable energy.

Now those that have experience of Anaerobic Digestion will know that with present technology the potential for the AD industry to provide renewable energy is large enough to be worthwhile, but not that big. Even with a very high rate of adoption AD will not provide enough power to meet the demand as a major contributor to the 80% reduction target. To do that would need a technical revolution.

But, again quoting from the NCE article, Ofwat’s head of Climate Change Policy Mike Keil has said that:

“Looking at the next five to ten years you can say with some certainty there won't be a technical revolution. Certainly there will be innovation contributing to carbon reductions, but not a huge step change".

Beyond 2020 it is possible there will be breakthroughs as research and development bears fruit and new technologies come to maturity.

So, based on current technologies, an 80% reduction looks extremely difficult, if not verging on impossible, to achieve. The lack of hard commitments from the Copenhagen Summit contributes to a feeling that the political commitment to “pledges” far outweighs the ability to deliver, given the enormity of the task ahead.

Nevertheless, it is important that Engineers do push forward where this can be done on the basis of economically justifiable results. That is where the prospects for UK Anaerobic Digestion do look very good indeed.

Again, referring to the Water Industry; In the next investment period the UK water companies will be making the most of the opportunities offered by enhanced sewage sludge digestion technologies to generate high calorific biogas and reduce the final volume of biosolids as waste for disposal. Adding hydrolysis up front before the digester will help to greatly increase the amount of conversion of the total biomass in sludge to methane, for example.

Another development to continue will be that:

"By using biogas to drive combined heat and power engines, enhanced biodigestion offers potential to make sewage treatment works energy self-sufficient," 

says Mott MacDonald head of water regulation Andrew Heather [again quoted here from the NCE article].

Some companies, we are told, are also planning to clean-up biogas so that it can be used as a vehicle fuel or sold into the national gas grid. It will be interesting to report on that in this blog in due course.

In addition to the digestion of their own sewage works sludge some Water Companies are also, we are told, looking to increase energy from biodigestion by supplementing sewage sludge with food and industrial waste.

So, the prospects for Anaerobic Digestion are good, but the big question mark, which continues to become more urgent to answer remains.

Where will the rest of these carbon savings come from, which are so badly needed to plug the huge gap between current reality and an 80% saving?

Answers to Recent Questions About Anaerobic Digestion from the Public

Why Would a Farmer Choose Anaerobic Digestion?

Waste biomass from farming and food-industries, such as slurries and the organic waste from food processing can present a considerable waste disposal problem. Release of large quantities of organic wastes into local water courses or seepage into ground water results in pollution of water courses and water supply. To prevent this occurring, the biomass needs to be treated and suitably stored and Anaerobic Digestion is a great way to achieve this.

Biogas is produced by the natural microbial degradation under anaerobic conditions. This technique has been applied to agricultural wastes world-wide on a small scale. Treating the waste by AD gives some environmental benefits, and in addition to AD also results in energy, in the form of biogas. Biogas is an inflammable gas, which can easily be used to generate electricity and heat. The potential benefits are many from on-farm and local use of fossil fuels and provision of energy within rural communities.

Some commentators have said that in addition to energy production, there is considerable potential for Anaerobic Digestion to assist in centrally managing the distribution of plant nutrients in manures, together with minimising biosecurity risks (ie pathogen kill).

Where is Anaerobic Digestion Most Popular?

In countries such as Denmark, Sweden, Germany, Austria and Switzerland there are many examples of co-digestion of farm manure with other suitable organic wastes in prefabricated digestors. There is a large interest in this option in these countries and in other countries both inside and outside the EU.

The most successful digesters utilize all energy produced. The most efficient use of biogas is direct heating. If biogas is burned in an electric generator, the heat produced by the engine must be harnessed and used in order to achieve optimum efficiency. The electricity produced can be used on site or sold into the power grid.

What Happens to the Sludge After the AD Process?

Once the digestion process is complete, the digested manure, or effluent, is released from the digester and stored until it is land applied. The digestion process breaks down many of the solids contained in the manure. As a result, the effluent causes less stress on pumps and agitation equipment than manure does. Also, effluent is homogeneous and may not require agitation prior to land application.

Many agri-food AD systems are located on farms. Farm-based AD systems work well with liquid manure. AD systems provide a valuable manure treatment option, since most other economically effective manure treatment systems (such as composting) require solid materials with dry matter greater than 30%.

What are the Most Popular AD Types of Plants?

Biogas from biomass has historically been used in Asia as a fuel for household uses such as cooking. Denmark and Germany have many modern digesters operating on farms and in central locations using materials such as manure, energy crops, and food-based products and byproducts. These systems typically use biogas to produce electricity and heat.

Anaerobic digestion (AD) plants can be on-farm units, designed to deal with manures and other organic materials produced at farm level. Alternatively, AD plants can be designed as centralised units to deal with products from a number of farms, along with co-digestion of organic materials from other industries.

AD plants can include mechanical separation of fibrous solids from the digestate that, after further processing, can give a value added product, such as compost or pellets (fertiliser or combustible fuel).

How Would I recognise an Anaerobic Digestion Plant if I Saw One?

Anaerobic Digesters themselves are completely sealed vessels which are covered and sealed. Most are insulated and heated, and the digester is an immediatelely recognisable feature at most large biogas plants as a large tall, usually vertical sided, circular tank, with an access ladder and a number of pipes leading to the top where there is also usually a pedestrian access way and handrail.

Biogas plant digesters of this type can usually be spotted very easily when you see them by the characteristic pairing of the digester with the biogas storage tank which acts like a traditional town gas ‘gasometer’, and is usually elegantly curved or “globe” shaped. Many visibly expand and contract to accommodate the volume of biogas present, the result is that most of them become significant landmark features.

Anaerobic Digestion Technologies to Get Help Through Feed-in-Tariffs

The following has been posted in MRW, and is great news for the future of UK AD.

Financial support for anaerobic digestion
Liz Gyekye, 02 Feb 2010

The Government has announced ambitious plans to provide financial support for anaerobic digestion technologies through feed-in-tariffs (FITs) and the “world’s first” renewable heat incentive scheme.

The schemes are designed to bring about a significant increase in the amount of locally produced green energy and help the UK meet its renewable energy targets.

FITs is a financial support system that will incentivise small scale low-carbon electricity generation by providing “clean energy cashback” for householders, communities and businesses. It will work alongside the Renewables Obligation, which will remain the primary mechanism to incentivise deployment of large-scale renewable electricity generation.

The FITs scheme will start from April 1 and will support new AD plants with a five megawatts limit capacity. The scheme will also support the first 30,000 combined heat and power installations with an electrical capacity of two kilowatts or less, as a pilot programme.

Under the FITs scheme AD operators will be paid for every kilowatt hour of electricity generated and metered by a generator. Farm scale AD operators, producing less than 500kW a year will get 11.5 pence/kWh per year over a 20 year period. AD operators producing more than 500KW will get 9p/kWh.

Speaking at the launch of the FITs scheme in London [February 1], Energy Minister Lord Hunt told MRW that he thought the FITs would encourage more AD plants to be built. He said: “I think that we have made an adjustment in order to make small scale AD more attractive. I think that the farming community will be very welcoming of this news. I very much hope that we will see a big market growing for AD.”

Energy and Climate Change Secretary Ed Miliband added: “Where there is muck there is brass!
“The FIT will change the way householders and communities think about their future energy needs, making the payback for investment far shorter than in the past.”

The Government also launched its consultation on the RHI scheme [February 1].

The RHI scheme is a financial support mechanism for individuals, communities and businesses that aims to incentivise low carbon heating and will be introduced in April 2011.

Under the RHI scheme, the proposed tariff for solid biomass technology operators will be 9p/kWh, biogas on-site combustion plants will get 5.5p/kWh and biomethane injection technology will get 4p/kWh.

Solid biomass can include municipal wastes and biogas can be upgraded to biomethane, which has similar thermal characteristics to natural gas and can be injected into the grid.
Where a plant can generate heat from both renewable and non-renewable fuels, the RHI tariff will only reward the renewable component of the mixed fuel load. The RHI consultation stated that this will usually involve combined heat and power using energy-from-waste.

Anaerobic Digestion and Biogas Association chair Lord Redesdale said that he was disappointed at the Government’s announcements on FIT and RHI. He said the Government had “horlicked” the whole thing. He explained: “It is unfortunate that the tariff has come in at nine pence which shows a distinct lack of enthusiasm. We thought it was going to be more than this and were hoping for 13p.

“To meet our climate change and renewable energy targets we need as much AD as we can possibly muster. Both the RHI and FITS have not met expectations from industry.

“The purpose of the tariff is to encourage entry in the market place but this is not going to be the case because the tariffs are too low. How many plants will be built out of this next year on this basis? If there is not enough plant going to be built you question whether the whole thing has been a success or not.”

Lord Redesdale also said that the AD industry was concerned with the issue of “grandfathering” of Renewable Obligation Certificates (see MRW story).Government is likely to alter tariffs for new levels for new projects from time to time to respond to changes in technology costs. However, once installation of a project has been completed, investors will consider it important that its support levels are not changed. Such a guarantee not to change support for existing projects is known as grandfathering.

At the moment biomass technologies, such as AD, are not protected through grandfathering.

However, the RHI consultation states: “We are nevertheless inclined to provide the RHI tariffs as grandfathered tariffs.” More...

US Climate Bill Setback and Clean Development Rethink on Renewable Energy Developments

All those interested in Anaerobic digestion and how demand for the technology might increase over the next few years have no doubt been watching the news on the post Copenhagen Summit devlopments, keenly.

Clearly, the way the US acts now will be important for the prospects of continuation after 2012 of Carbon Credit schemes under the "Clean Development Mechanism", such as the EU ETS. The growth of Anaerobic Digestion based technology utilisation is assured in many developed nations, but I would also would expect to see a surge of advanced technology based AD Plant development in the industrializing nations once the post 2012 Climate Emission Reductions (CERs) become tradable.

The following is a 22 January Reuters post, which provides an update on the US scene:

LONDON (Reuters) - Still reeling from disappointing UN climate talks in Copenhagen in December, clean energy project developers were dealt another blow this week when U.S. Democrats lost their Senate supermajority, potentially killing a federal cap-and-trade scheme for years to come.

Although the passage of a U.S. bill to cap greenhouse gas emissions in 2010 was far from certain, the election of a Republican in Massachusetts to the Senate on Tuesday derailed any momentum President Obama had following his healthcare push toward introducing a cap-and-trade scheme this year.

This, coupled with a disappointing UN climate summit in the Danish capital last month where leaders from over 190 countries failed to agree a legally-binding pact to succeed the Kyoto Protocol, is causing concern for some clean energy project developers and forcing them to reassess their game plan.

"I'm not as bullish as I was a year ago," said Sascha Lafeld, an executive board member at First Climate AG. "The U.S. pre-compliance market is cautiously developing, so our strategy is also one of caution ... We're on hold, we'll keep our two U.S. offices open but we're not expanding this year."

Frankfurt-based First Climate has a global project portfolio of some 250 projects, including around 20 projects in the U.S., that generate carbon offsets by cutting carbon dioxide.

Observers say the spotlight in the U.S. now shifts back to state and regional schemes launched by a handful of states during George W. Bush's presidency, when the prospect of a federal U.S. carbon market was a distant mirage.

"It's not ideal but we welcome this as a fallback solution," said Alexander Sarac of JP Morgan-owned EcoSecurities, one of the world's biggest aggregators of carbon offsets.

For the full article visit:

http://uk.reuters.com/article/idUKTRE60L4DE20100122

Manure to Become Megawatts in Newcastle University Project

A £1.85M project looking at techniques of converting farm waste products into electricity is to go ahead in the North East.

A state-of-the-art anaerobic digester which converts manure from pigs and cattle into green electricity is arranged for being installed at Cockle Park Farm by Newcastle College thanks to an £860,000 cash injection from regional improvement agency One North East.

The idea is one of assisting farms turn into far more sustainable businesses, the goal is to join with North East farmers, land managers and other associated organisations to find new means for making renewable electric from waste material.

Ths project is joint funded by the college and One North East through its Rural Development Programme for England (RDPE), the anaerobic digester will form a portion on the new Centre for Renewable Energy from Land (CREEL) launched by Newcastle University.

The promoters of this project have put in a good deal of work which has gone into arranging this challenge up to this point, so they say that it is extremely thrilling to have at last received both funding and 3rd party permission for this project.

Anaerobic digestion presents enormous potential in terms of utilizing the methane from animal waste materials and converting it into renewable electric power which will be utilized to heat and supply energy to the buildings on the farm.

By working together using the agricultural business they hope to produce a new means of producing anaerobic digestion and viable technology for uptake by farms throughout the UK.

The residual digestate might be applied being a soil conditioner and a nutrient source and offers considerable probable for farmers to reduce their fertilizer budget. Read more here...

Mechanical Biological Treatment Process with AD Explained

The New Civil Engineer magazine has published (19 November edition 2009) a refreshingly down to earth description of the process which will soon start to mechanically and biologically treat a part of Manchester’s residual (black bag) Municipal Solid Waste (MSW). The following was stated by Peter Harvey in his role as the Business Director of Enpure (Process Engineering). Enpure is the encumbent EPC Contractor, in the Greater Manchester Waste Disposal Authority’s huge city-wide PFI waste management contract.

This multi-billion contract was finally let around about last Easter after extended delays, and not least the problems caused by the credit crunch last Autumn. Under this Contract, Enpure is the EPC Contractor which will provide processing facilities for the PPP Consortium Laing Viridor to operate two MBT Facilities to be built at Reliance Street and Bredbury, under a £57 million Contract.

(In MBT there is always a choice to be made between composting to reduce the activity of the organic material before it goes to landfill, which is of dubious merit, or Anaerobic Digestion which does a better job but requires more investment and some risk of not repaying that investment. - Added by your Blogmaster)

"There are a number of ways that you can biologically treat that [smaller fraction], composting for example, or anaerobic digestion which can then create methane for electricity production. That particular approach [anaerobic digestion] is what we have on our two MBT projects," says Peter Harvey.

The process begins at the materials recovery facility (MRF) whereby black bag [mixed residual] waste (MSW) goes through a very coarse shredder that reduces waste to 250mm to 300mm pieces. At that point the waste is screened and material of less than 80mm (the organic fraction) goes off for anaerobic digestion.

But first it needs further separation. "If we didn't clean it up then grit, pieces of plastic and bits of rubble could cause blockages so we have a very sophisticated wet separation process called the hydro-pulper".

It is this pulper which has not been used before in the UK. It comes from German firm BTA International. "It is a vessel with a high speed impeller in the centre that will transfer any organic material, paper, cardboard, food and organic matter into a sludge, which we can then pass through a screen and into the digesters," says Phil Harvey.

Just under 5MW of electricity will be generated by the Reliance Street and Bredbury facilities to fuel the MBT process and feed back into the grid. "Between these two facilities there is enough to power 10,000 homes from the biogas alone.

As for the larger components, these are sorted for recycling in the case of metals and plastics, or for sending on as Refuse Derived Fuel (RDF) to Runcorn [for incineration].

The fraction above 80mm is then put through a density separation process so that we can eliminate any hardcore material from that size fraction.

Then there is metals removal. After this it is shredded to 30mm ready for RDF production.

We also have an air knife which blows off plastics into the RDF as well.

At Reliance Street the treatment process will handle 100,000t of waste per annum, but only 63,000t of this will go through the MBT plant. The rest, larger particles over 45mm, is sorted out and sent off for recycling.


"The only real difference between the two sites is the degree of sorting that happens before the wet preparation stage," says Peter Harvey.


Of course with plants handling so much waste material and especially the Anaerobic Digestion present, there has clearly and quite understandably been much concern about odours.

Because Reliance Street is right in the city it uses a sophisticated odour control process called regenerative thermal oxidation. The odour is collected via ducts and blown into the treatment system which uses heat in the presence of a catalyst to thermally oxidise the odorous compounds in the air. The heat from the treated air is captured using silicon tiles.

"Bredbury has a more conventional odour system, we operate the buildings under negative pressure so that if there are any leaks they go into the building rather than out and all that air is treated with biofilters," says Peter Harvey.