Wednesday, December 31, 2014

2014: A Great Year for Anaerobic Digestion and Biogas in the U.S.

2014 will probably be seen in years to come as a turning point in the development of the anaerobic digestion and biogas energy industry in the U.S.: The year when their industry came of age and finally began to take-off in terms of business.

Last year the USDA, with the EPA and DOE at their side, published a Biogas Opportunities Roadmap report. It described the steps that these three Federal Agencies will take to increase the uptake of the anaerobic digestion with the development of many more biogas plants in the United States, on a scale hardly even imagined previously.

Will 2014 be seen as the year when this "banana power" prediction finally
became accepted in the mind of US businesses?
Their "Roadmap" outlines the ways in which those that want to promote waste fed anaerobic digestion projects will be able to overcome the current regulatory restrictions which have been holding back the development of a healthy (energy from waste) biogas industry in the U.S.

There is no doubt that this will end up creating new jobs, and injecting cash into the nations economy. At the same time these agencies recognise, that an important part of the Roadmap is in its aims to educate the public on the benefits which will flow from biogas development. Within these benefits is of course the ability of these biogas plants to reduce Greenhouse Gas emissions, and in this and in other ways lead to improvement in the nation's environmental quality.

Within the Roadmap there are more than 10,000 farms where it is estimated one of these new alternative energy producing waste processing plants should be built in just a few short years, so the young biogas industry will have plenty to be doing. This news has been welcomed by the American Biogas Association, which is the main industry trade body.

For years, third world ranchers have been using methane from manure to run electrical generators down on the farm. This low pollutant emitting biogas is not only a good local fuel in countries with little or no infrastructure, now even countries like the U.S. will be reaping energy from what is otherwise a very smelly resource.

About 80 percent of the estimated only 160 biogas energy projects in the U.S. are currently installed on dairy farms, which then combust the gas to generate electricity. The combined installed capacity of all dairy farm projects is now nearly 60 MW, and should now rise rapidly.

Until now the value of biogas was not properly understood. Because of that there has been an absence of training and regulation standards. Biogas industry data is under-developed and it has been difficult to secure finance, but in 2015 that should all start to change.

In huge tanks, bacteria will turn waste into methane gas, which is burned in turbines or engines that generate electric power. Each large biogas plant can generate as much as a wind turbine, but this energy is far more valauble as it is generated continuously and is not weather dependent. After methanization, the "digestate" produced is further composted and turned into fertilizer that is used by farms in the region.

Looking back at the last 12 months we wanted to share another biogas development which was one of our favorite moments.

In a recent issue of Biomass Magazine, it was explained that there has been staggering growth in the use of cellulosis renewable information number (RIN) market. To you and me this means that existing alternative energy plants are making much more of it, from compressed natural gas (CNG) to liquified natural gas (LNG). In fact, this renewable energy output surged from 3.5 million in August 2014 to 7.5 million in September 2014, presumably due to new plants coming on-stream.

Also, in 2014, municipalities and others who have long been looking for ways to make the best possible use of landfill gas (LFG) created by anaerobic processes at their landfills, will have been further encouraged to go ahead with landfill gas collection schemes. In 2015 and beyond, many more of these should now be equipped with biogas upgrading equipment, and be used to fuel waste collection fleets, or simply sell the compressed biomethane as CNG.

http://images.anaerobic-digestion.com/meme/view/Biogas Explosion!/535ab20138acfhttp://images.anaerobic-digestion.com/meme/view/Wikifibs Funny History of Biogas No. 1/52ee606582163 http://images.anaerobic-digestion.com/meme/view/Biogas Engines Run On A Futureproof Fuel: Her Lifetimes Energy Could Be Guaranteed.../52eee957a55c1

Another feature in 2014, has been the number of bodies such as universities and computer data-centre operators that have "gone green", and are generating their own electricity from organic waste. Many have installed their own biogas plants, and a number of those are using fuel cells. These fuel cells convert biogas to electricity through an electrochemical process that also reduces nitrogen oxide, sulfur dioxide and particulate matter emissions, usually by more than 70%.

The California Energy Commission was also in the news and is promoting the production of biomethane through regulatory measures. So, California is also keen to see increased uptake of biogas and is seeking ways to capitalize on the emerging high energy feedstocks available in the state. These include wastewater, municipal solid waste and industrial food waste. 2014 has seen them exploring how to encourage  utility businesses to install biogas plants, and get the potential consumers of this new alternative energy to use it. This has produced much needed publicity on the market prospects for biomethane, not least in the natural gas powered vehicle market.

In the 1985 blockbuster “Back to the Future” there was a scene when a banana peel was needed to fuel a Delorean.

Not much happened to bring such a prediction into reality in the US until around 2012 when several major project developments were successfully brought on-stream, across the United States. The first food waste digesters were also coming online at that time, and since then they have shown their worth.

Move on to 2014, and finally all the "technology talk" of previous years seems to be being brought forward to real action on the ground. Throughout 2014, federal, state, and local market involvements have been propelling developments forward in anaerobic digestion and biogas plant implementation.

We hope you enjoyed this article, and wish all our readers a very HAPPY NEW YEAR! Don't forget that we do have a comments section below this blog! Did we get our opinion of US events in 2014 right? Your feedback is important to us.

Tuesday, December 09, 2014

Why Better Digestate Enhancement and Treatment is What the Biogas Industry Needs

Digestate Enhancement is Important!

The operating capacity of biogas plants in the UK is rising faster all the time. The technology has recently also been extended from the original use on farms with energy crops, into new areas. Two of these rapidly expanding Anaerobic Digestion (AD) Plant sectors, in the UK, are in sewage sludge treatment, and food waste disposal.

Both of these applications for AD makes real sense due to the energy that this releases which can be used in turn to power the wastewater treatment works at which the AD facility is located, and similar uses also exist at facilities accepting food waste

In our opinion this goes further because of the use of biogas digesters for the treatment of sewage sludge with the ability to pay for the AD Plant, at least in part, from the sale of the biogas or electricity generated from it. This is now becoming the accepted practise in the UK, and we are certain that the same applies in a number of other nations.

However, using biogas digesters for organic wastes from sources such as food waste has much less of a proven performance history. In fact, only in 2011, there were concerns that completely food waste fed anaerobic digestion plants might not be feasible in the long term due to process instability problems.

This anticipated obstacle has been eliminated by the results of published studies carried out by the University of Southampton, however, this example just goes to show how very recently the scientific community was still talking about whether this kind of biogas digester would work dependably, or go sour! Fast foward to today, we still are no more than 2 to 3 years after that event, and many large food waste biogas plants have actually now already been commissioned! In addition it is likely that in less than 5 years there will be legislation in the UK which will legally require that food waste be separately collected by all councils, and anaerobically digested.

The end-result of this rapid take-up of a new technological application, has in-truth been that there has actually been hardly any time for much study work to be  done on digestate disposal and/ or sales/ product improvements, when compared to other aspects of biogas manufacturing.

It is an inescapable fact that 90 to 95 % of the original feed product which goes into a biogas digester re-appears as digestate from the digester as digestate, and if the digester is running properly the mass decrease is merely the mass of the biogas created. the techniques by which any AD Plant handles digestate is therefore of big relevance to plant operation and to the financial practicality of each plant.

With the undeniable increased popularity of waste digestion, the need to enhance the available strategies for managing digestate, as a helpful resource, and not just as a waste for disposal, is pressing.

The next breakthrough the Anaerobic Digestion industry badly now needs is certainly in improving the optimization of digestate by inventing better techniques, and treatment, with the aim being to open-up this product to new, much bigger, and more rewarding markets.

Barriers encountered in the UK to finding better ways to enhance and treat digestate were identified in a recent study for WRAP. Read more abut those barriers to digestate enhancement here. 

Saturday, October 11, 2014

5 Most Critical Factors in the Design of Every Biogas Plant - Xergi List

The five design factors which can make or break the success of a Biogas Plant Project, is a list inspired by a pdf available on the Xergi website. Our interpretation of their list follows:

The 5 most essential aspects of the design of any anaerobic digestion plant can be listed as:

1. A High Degree of Flexibility

Biogas plants are complex even without consideration of the fact that the feed materials are waste products. They vary not only seasonally, but according to market forces and what the waste producer is doing in their business at any time. Not only that, as any biogas plant operator will tell you, it is necessary to feed the digester with the right mix of "woody" and "green" at all times.

If you perfer to view this on the YouTube website click here for this Xergi Biogas Top Design Success Factors video.

So, all biogas plant designs need to come with a huge dose of flexibility across just about any parameter that you consider. This is essential, when it comes to providing a plant which will be sufficiently adaptable to the clients needs throughout the lifetime of the biogas plant.

2. Dosing Equipment With The Ability To Handle All Types Of Feed Materials

No biogas plant can work well for long unless the operator is able to set the relative feed materials (substrate) proportions and overall input flows to what is needed for the good of the biomass in the digesters at any time, and for the equipment to reliably deliver that dose.

In most processes the input (raw material) is known (because it is bought-in to a specification). Waste deliveries to an AD Plant are the complete opposite. Nothing is the same for two days running when it is waste that is the raw material and is collected from the public and businesses.

This is a challenge for dosing equipment designers, and not all of them are up to scratch on the ability of their pre-treatment of waste arriving at the biogas plant to sort, mix, and break the material down into a transportable/ pump-able quantity of biogas plant feed accurately, and daily over long periods in-between maintenance dates.

3. Adopting an Ideal Process Temperature

Thermophilic AD Plants provide optimum gas yields within the shortest period of time (average particle residence time in the reactor), so it is important for the economic benefit of the biogas project that the best rates of reaction are achieved, and by experience a company like Xergi is well versed in balancing demanding cost factors for choice the best process operating temperature.

4. High Efficiency Mixing

Mixing demands are hard to meet in the fermentation process, as the mixture has a comparatively high viscosity, and fibrous materials can cause reduced equipment availability.

Within the biogas industry there are many ways to achieve biogas reactor mixing, some solutions are generic and have been around for many years. But, many of the best now, which are now avialable are compartaively cheap to run and provide the closest approximation to perfect mixing, are proprietory.

Xergi for example has its own in-house mixing technology to ensure that the mixing function is reliably available to provide something like the features of a fully-mixed reactor (fermenter).

5. Remote Control of Operating Systems

Biogas plants need to be readily accessible by remote control to operational managers 24/7, including at times while off-duty. Production of power has to continue all the time, so remote control must not only be available, but capable of being used easily on multiple computing device types, including from a small smartphone 

For further information visit the Xergi website here: www.xergi.com

Sunday, October 05, 2014

Many UK Anaerobic Digester Planning Applications Still Public Relations Disaster

Objections are Understandable After UK AD Plant Leaks
New anaerobic digestion plant projects are being put forward for planning permission in increasing numbers in the UK, but many are facing heavy local opposition.

In fact it isn't unreasonable to label many of these planning applications as a public relations disaster. 

In this post we have highlighted just three biogas plant applications to provide a flavour for the public reactions received. In the first example, it is clear that the residents of the quiet market town of Whitchurch in Shropshire are very concerned about the possible negative impacts of this anaerobic digestion project.

1000 sign petition against Whitchurch anaerobic digester - shropshirestar.com

"1000 sign petition against Whitchurch anaerobic digester. Shropshirestar.com - One of the group's campaigners Sue Whitson said:
“We have been collecting signatures against the proposed digester for some weeks now and have had petitions in a number of business premises in the town as well as collecting signatures on-line."
http://news.google.com/news/url?sa=t&fd=R&ct2=uk&usg=AFQjCNFom0JICmkFJ3NMI0NYrbGShWVXHQ&clid=c3a7d30bb8a4878e06b80cf16b898331&ei=J6cxVOCnEuG9igaK-4DACg&url=http://www.shropshirestar.com/news/2014/09/11/1000-sign-petition-against-whitchurch-anaerobic-digester/
In the article it becomes clear that an incident at an AD Plant not far away, is on the minds of many of the people of Whitchurch. We reported upon that tank collapse and digestate leak here:
"So far, Whitchurch Town and Parish Councils have objected to the plans on the grounds of potential smell and negative environmental impacts.
Planning experts always say that the secret to avoiding objections to any controversial project is early consultation, and spending time with the locals to make the case for the AD Plant and allay fears, if necessary modifying your proposals before the full application for planning permission is submitted. The next link suggests that this may be the approach being used in this case, but it is unclear whether the plannign application has yet been made:

More than 120 Wimblington people have their say on Fengrain ... - Wisbech Standard
"Wisbech Standard - GALLERY: More than 120 Wimblington people have their say on Fengrain ...Wisbech Standard - Public meeting about the Anaerobic digestion for Fengrain, Held at Wimblington parish hall. Left: Mick Knight resident and organiser of the meeting. Cllr David Connor, Chairman David Green,Speaker Charlie Graham-Cameron.Picture: Steve Williams.and more »" http://news.google.com/news/url?sa=t&fd=R&ct2=uk&usg=AFQjCNFQJEhjv3-8ekI8q9HBa9IuNSMTUQ&clid=c3a7d30bb8a4878e06b80cf16b898331&cid=52778602410076&ei=J6cxVOCnEuG9igaK-4DACg&url=http://www.wisbechstandard.co.uk/news/gallery_more_than_120_wimblington_people_have_their_say_on_fengrain_anaerobic_digester_plans_at_public_meeting_1_3759096
Clearly, the UK anaerobic digestion industry needs to do better with its public relations. That the public are against this AD Plant going ahead is evident from the following quotation from the article:
"Mr Barclay revealed the result of the contrasting petitions he put on his website for and against the digester – 151 voted against it, 11 people were in favour."
Finally, there are yet more biogas plant planning permission problems currently evident in the following example:
Developer appeals over green belt anaerobic digestion plant refusal - PlanningResource (subscription)
"Place North West - Developer appeals over green belt anaerobic digestion plant refusal. The developers behind a planned anaerobic digestion plant on a green belt site in Greater Manchester have appealed against a council's decision to turn down the application. Ramsbottom: developer to appeal energy plant refusal. The application, for the ...Controversial digestion plant developers lodge appeal against refusal. Bury Times: Appeal launched for Ramsbottom energy plant. Place North Westall 2 news articles »" http://news.google.com/news/url?sa=t&fd=R&ct2=uk&usg=AFQjCNHPd0gZeUrS6D4MNMRI33FKvIRH-w&clid=c3a7d30bb8a4878e06b80cf16b898331&cid=52778601344343&ei=J6cxVOCnEuG9igaK-4DACg&url=http://www.planningresource.co.uk/article/1310815/developer-appeals-green-belt-anaerobic-digestion-plant-refusal
However, it is clear that there will be many more AD Plants built in the near future throughout the UK if the following news, of a regulation that has been simplified, is anything to judge by:

Changes to UK's waste regulations favour anaerobic digestion industry - Renewable Energy Focus

"Changes to UK's waste regulations favour anaerobic digestion industry: Renewable Energy Focus - Biogas producers will no longer need to pay for permits or waste handling controls to use fruit and vegetable by-products in the anaerobic digestion (AD) process, the Environment Agency confirmed earlier this week.1 This resolves a long-standing ...and more »" http://news.google.com/news/url?sa=t&fd=R&ct2=uk&usg=AFQjCNGKDNO2Ub_ErMuL2Gv-G_2l-1KKDw&clid=c3a7d30bb8a4878e06b80cf16b898331&cid=52778607361466&ei=J6cxVOCnEuG9igaK-4DACg&url=http://www.renewableenergyfocus.com/view/39984/changes-to-uk-s-waste-regulations-favour-anaerobic-digestion-industry/
Taking the above reports into account does we suggest fully justify our view that many current UK Anaerobic Digester Planning Applications are still a Public Relations disaster. Does anyone have any suggestions as to how this situation can be improved?

Wednesday, October 01, 2014

Rise in Biogas Plant Blockages Causes Financial Losses at Food Waste AD Plants

As governments and biogas plant operators have woken up to the amount of food waste that modern societies produce, there has been a trend for existing biogas plant operators to start accepting food waste as an additional feed source.

But, that has been causing big trouble for many biogas plant operators. It is causing many plant pumping failures, and big losses to these businesses due to time-consuming plant downtime while clogged pipework is dismantled and rebuilt.

There is a solution to this so read-on to find out what it is!

The Food Waste Problem

By "food waste", we mean all kinds of waste from food processing plants to out-of-date supermarket food packets, and this may also include restaurant and office canteen waste. These are wastes which until 20 years ago, in many countries would have been fed to pigs, or rendered down into various types of cattle feed.

Watch our video below, in which we explain the problem! (Please try not to get too emotional while watching!!)

(If this video does not display well on you device, it can also be wtached by clicking here: http://youtu.be/RtRiCS8CoCk )

It was concern about the risks of infection spreading, such as "Foot and Mouth" and "BSE", that these types of wastes were deemed to cause if consumed as part of the food chain, which has lead to them becoming a "waste" and age-old practices for re-use of unwanted food, being banned. By preventing their consumption, the waste had to go somewhere, and has been resulting in huge tonnages which have been being landfilled to the detriment of landfills.

On the face of it, food waste should not be landfilled, and to do so is a huge waste of resources, because all the energy locked-up up in food makes it absolutely the best type of feedstock to use because it is the highest in calorific value. But, when an anaerobic digestion plant changes its feed material to food waste it also starts accepting a highly variable type of waste, and one which can vary greatly in viscosity and will almost always include a substantial amount of foreign matter, especially pieces of plastic and plastic film.

Existing Biogas Plant Pumps Are Often Not Suitable

Anaerobic Digestion plants built originally for manure and agricultural wastes/ energy crop digestion, and by some accounts also those designed by "experts" to accept food waste, are usually equipped with high solids passing centrifugal subtstrate pumping systems to deliver the feed into the digesters, and to remove it after digestion.

Such, "standard" pumps are being found inadequate and furthermore, as pipework starts to clog up, the flow rate from such pumps tends to drop, allowing yet more material to build-up within the pipework and eventually pumping stops when the pipe flow resistance overloads the pump system and all pumping ceases, until pipes and pumps are manually cleaned out.

To compound the problem, many AD Plants were never designed for the pipes to be dismantled and in such cases pipe replacement may be necessary.

The Solution

Pump experts recommend positive displacement pumps as the solution to this problem in combination with chopper or macerator pumps. An example is the Verderflex peristaltic pump series which when correctly installed is designed to reliably transport the chopped slurry from holding tanks and through the system to the digesters tank(s). This usually will be via a heat exchanger to raise the substrate’s temperature to a level suitable for efficient digestion, before it enters the AD plant digester tanks. The same type of pump may also be recommended for the outlet from the digester.

The Silver Lining Once Food Waste Problems are Solved!

With the right pump systems installed, biogas plants are capable of producing substantially more biogas from the higher calorific value food waste, so once upgraded pumping systems are working reliably, the pant operator can benefit from a significantly improved income from increased biogas energy sales.

For further information on peristaltic pumps and anaerobic digestion plant susbtrate/ digestate pumping, we sugest that you might do well to visit the Verder website at: www.Verder.co.uk

A case study pdf is also available on the Verder website, here:
www.verder.co.uk/AD___Biogas.pdf

Saturday, September 13, 2014

Biogas Market Grows Despite Uncertain Policies & Biomethane Inconsistencies

biogas



Paul Thompson, who is head of policy at the Renewable Energy Association (REA) has it right in his Guardian article "Renewables battle on in face of uncertain policies". Certainly, here in the UK the anaerobic digestion sector is seeing advances in AD plant scale and the sophistication of the technologies being installed which could only have been dreamed of even less than 5 years ago. Our readers might like to look at the Guardian article below:

Renewables battle on in face of uncertain policies - The Guardian

"Renewables battle on in face of uncertain policies: The Guardian
Paul Thompson, head of policy at the Renewable Energy Association (REA), says there's been increased entrepreneurial activity in biomass, bio-methane, anaerobic digestion and ground-source heat pumps. Solar PV is also starting to imagine life without ...and more »"
To find out more about "Renewables battle on in face of uncertain policies - The Guardian" and anaerobic digestion, click here

Nobody is suggesting that it isn't still a tough climate for renewable energy companies, suppliers, and green entrepreneurs. All credit to those companies who have sustained their businesses through tough times since the 2007/8 finacial crisis and can now begin to grow from a sound financial and product base. The race will now be on to achieve compliance with the targets for increased use of renewable energy sources, which in many cases were in place before the current UK political regime, have weathered it intact, and must continue to be complied with, if the UK as a nation expects others to follow with them, and after them.

One area in the Anaerobic Digestion Sector, which was largely a theoretical one but which is now growing rapidly in importance, is biogas upgarding and what is referred to as the production of biomethane, or natural gas/ CNG replacement. Success brings it own problems, and in this area a lack of consistent requirements from the operators of the existing national and regional gas networks is making life more difficult than it need be for the producers of biomethane.

That why it is cheering to read that International Energy Association members may get some help from an initiative by the IEA to improve consistency in the gas quality requirements and associated technical issues between the many gas distribution grid companies. The following article explains what is being done:

The biomethane market needs clear frame conditions for further growth - Phys.Org
"The biomethane market needs clear frame conditions for further growth. Biomethane as a substitute for the fossil energy carrier natural gas offers a variety of options and applications for a sustainable energy supply. Nevertheless, a consequent market penetration is still pending because of a lack of standardized and ..." http://news.google.com/news/url?sa=t&fd=R&ct2=us&usg=AFQjCNF36nsas7i8RJUkfw_HG5N5aak8gQ&clid=c3a7d30bb8a4878e06b80cf16b898331&ei=_U4UVOiBAo2YjAbq44H4DA&url=http://phys.org/news/2014-09-biomethane-conditions-growth.html
Finally, to end of this News Round-Up with a ground-breaking first commitment of its kind, we would like to highlight that still on the subject of biomethane, a major UK retail store has decided to back anaerobic digestion by buying the energy for its own use:

M&S buys into Biomethane Certification Scheme - Energy and Environmental Management (EAEM) Magazine

"Energy and Environmental Management (EAEM) Magazine: M&S buys into Biomethane Certification Scheme
The leading UK supermarket, Marks and Spencer plc, has bought the majority of Biomethane Certificates (BMCs) from the green gas produced at Future Biogas's new gas-to-grid anaerobic digestion plant near Doncaster. M&S is the first FTSE100 buyer to join ... M&S strikes landmark deal to buy biomethane certificates. Biomethane certification scheme wins M&S's backing as buyer - EPR Retail News (press release) news articles »" http://news.google.com/news/url?sa=t&fd=R&ct2=us&usg=AFQjCNFxLR-oe4WNpDIvmklCbBXgfz8vUg&clid=c3a7d30bb8a4878e06b80cf16b898331&cid=52778605188089&ei=_U4UVOiBAo2YjAbq44H4DA&url=http://www.eaem.co.uk/news/ms-buys-biomethane-certification-scheme
This should help yet more potential biogas producers, who are still on the fence about investing in new biogas plants, to feel confident in the technology and the future market demand, which in our opinion will certainly continue to grow and should accelerate.

Wednesday, September 03, 2014

Biogas Success - Weltec Biopower To Build Piddlehinton AD Plant 1.1 MW Extension

Weltec Biopower Awarded 1.1 MW Piddlehinton AD Plant Extension

A highly successful food waste biogas plant constructed by Weltec, after only 2 years of operation is being enlarged. Now there's confidence in the profitability of food waste anaerobic digestion!


Watch our video on this project below:

Press release · Communiqué de presse
Vechta, September 2014: 

WELTEC BIOPOWER receives order for 1.1 MW extension in Dorset

Award-Winning AD plant processes food waste to energy

Weltec Biopower (UK) Ltd, based in Stoneleigh, Warwickshire, UK, has been granted the contract to extend the award-winning food waste AD plant in Piddlehinton, Dorset. Plant owners Eco Sustainable Solutions Ltd. are expanding with a further 1.1MW of food waste processing capacity. 

This follows on from the Weltec successes of commissioning two other plants in early 2014. The original Eco-Dorset AD plant was also built by WELTEC and was commissioned in 2012. After two years of successful operation, the operator assigned WELTEC with the extension. The extension will be completed in autumn 2014. 

Another advantage core to WELTEC’s continued success in industrial and agricultural applications is the fact that the digesters and digestate storage tanks are constructed from stainless steel. Aside from being a higher-quality product, stainless steel and is corrosion resistant to aggressive materials and offers a faster construction time, which is increasingly important to all developers with the FIT framework deadlines providing tight construction windows. 

Watch our new video "How Does a Biogas plant Work?"

After two years of successful operation, the operator assigned WELTEC with the extension. The extension will be completed in autumn 2014. The plant is fed by local authority food waste as well as out of date food products which prior to digestion are unpackaged, sorted and pasteurised at the site. After the extension, approximately 37,000 tpa of food waste will generate an electrical output of 1.6 MW. 

The Eco-Dorset approach is an excellent example of the benefits of intelligent design, co-location and mutually beneficial plant integration. Electricity generated at the plant as well as excess gas is fed to an adjacent feed mill. When the mill is not operational, the power is fed to the National Grid. The digestate produced by the plant, which is in the process of gaining PAS 110 accreditation, is collected and used by local farmers. 

Despite the latent renewable energy in commercial and municipal food wastes, much of this valuable resource still ends in landfill. Much of it also ends in composting plants, which use expensive imported energy to bio-stabilise (or destroy) what, when processed in an AD plant, is a valuable renewable energy resource. After all, one tonne of organic waste processed through AD, could be converted into 600 to 800 kilowatt hours of energy – enough to power five refrigerators for one year. 

The equivalent tonne of waste through a composting plant costs energy and money to process. As energy demand and prices continue to rise and security of supply concerns worsen, more and more Local Authorities and private waste companies look set to follow the excellent example set by Eco Sustainable Solutions Ltd. and capitalize on the excellent income generation opportunity that organic waste presents. 

WELTEC understands the needs of every client and tailors the most cost-effective solution on a case by case basis. The partnership between the plant manufacturer and his clients also maintain after the design and build phase. “We recognize that an AD plant is a 20 year partnership and that maintaining solid trust-based working relationships with our clients is crucial to our ongoing success. 

Therefore we now have a dedicated UK-based Service and Maintenance capability with locally available spare parts”, sales manager Kevin Monson explains. 

Company Portrait

In 2014, WELTEC BIOPOWER GmbH, one of the first manufacturers of biogas plants, celebrated its 13th anniversary. WELTEC is one of the pioneers of the constructors of biogas plants. 

Based on the modern approach of experienced engineers, the company from Vechta, Germany with its expertise of a staff of close to 80, offers complete biogas plants from one source and has developed to a leading constructor of biogas plants in the world. As the hydrogen sulphide and ammonia compounds contained in biogas corrode unprotected parts, WELTEC builds the digesters from stainless steel. This ensures a long useful life of the plant. The manufacturing depth also guarantees a consistently high standard regardless of the location and ensures an export rate that is far above the industry average. 

The plants have a modular structure. WELTEC uses only proven system components and develops most of the technologies along the entire value chain internally: digester technology, mixing technology, control technology, hygienisation systems, and digestate processing solutions originate from the company. 

By means of its comprehensive services, WELTEC ensures the technical and economic stability of the biogas plants. The CHP service guarantees stable output, the biological supervision ensures continuous monitoring of the relevant parameters, and systematic repowering makes sure that the biogas plant is always up to date. 

Operators can choose from a range of service packages of different types and scope. One of the main strengths of WELTEC is the ability to deliver individual and flexible solutions worldwide – from compact plants to large computer-controlled plants in the megawatt range, waste recycling plants, and biogas parks with gas processing technology.

Ann Börries
Marketing
Phone: +49 4441/99978-220
Email: presse@weltec-biopower.de

Wednesday, August 20, 2014

New Low Temperature Anaerobic Digestion Process Reviewed

Low Temperature Anaerobic Digestion - It Is The Third Type Of AD Process

I was fascinated to discover a new company with their own stand at the AD & Biogas Association (AD&B) Exhibition and Conference 2014, which was held last month at the NEC Birmingham, UK.  Irish start-up NVP Energy was the company in question, and they were there to present their unique and innovative low temperature (< 20°C) Anaerobic Digestion (Lt-AD) wastewater (WW) treatment technology for medium to low-strength industrial effluents.

And, yes! You did just read “less than 20 degrees Centigrade”, so this is a truly ambient temperature process for use in our cold northern European climate, without costly insulation and heating.

If you have ever wondered why so many digesters in the UK (of the mesophilic and thermophilic variety), are a lot less productive than those un-insulated anaerobic digestion systems which seem miraculously easy to build and operate in hot climates, it has got an awful lot to do with our climate being too cold, and the cost of heating!

Watch our sponsored Lt_AD explainer video below:

To view this video on the YouTube website click here and watch Low Temperature Anaerobic Digestion being explained.

So, how remarkable to find that a spin-off technology, which has taken 15 years microbiological lab and pilot scale testing at the National University of Ireland, Galway is now available for the Food and Drink Wastewater (WW) industry. Not only that there are many other industries which produce similar strength organic effluents such as the Municipal WW industry, Pharmaceutical WW industry, and also the ethanol processing WW industry. All thse can now use this technology to treat their wastewater without the ever-rising energy (running) cost implications of current aerobic treatment systems.

But like all other anaerobic digestion based processes LT-AD has, is also by nature biogas plant, with all the implications that brings for net energy export (and revenue), reduced carbon footprint for the business, and even possible sales for other products such as CO2, and the digestate as a fertilizer.

Traditionally all these industries have used aerobic wastewater treatment systems, the Lt-AD technology does what those high energy consuming systems can do. It recovers the carbon in the WW and transforms it into biogas. This means that the NVP Energy technology is a carbon neutral and energy-positive process technology which is great news for the global environment. But, lets not forget the benefits to the bottom line for those that use this new process, due to those reduced carbon costs.

If you have been watching how quickly anaerobic digestion taking hold as the preferred treatment method of choice, then just take a look at this blog! Due to its clean green energy credentials Ad is leaping ahead, and this development should be very attractive to the Food and Drinks industry, plus all other businesses producing similar effluents.
AD-Lt Anaerobic digestion 3D Image cut-away
The NVP Energy process has been given the name of “Lt-AD technology” and they say that it can work equally well as a retrofit, an add-on technology to their client’s business expansion, or of course can be the core technology treatment method in any new build scenario.
For example, if you operate a Food & Drink plant that has an existing inefficient WWT system such as the activated sludge system, then their technology can:
  • Lessen the load on your current system and greatly reduce your aeration costs due to our high COD attenuation
  • Significantly decrease your sludge volumes. Their technology has been shown to generate up to 90% less organic sludge compared to the activated sludge process.
On the other hand, if you operate a Food & Drink plant that elutes all your wastewater to sewer, then their technology can:
  • Significantly reduce your trade effluent charge/Mogden charge due to high COD & TSS attenuation.
In both cases the biogas that is produced is 100% available for reuse on-site to generate heat and/or electricity thus reducing your operational expenditure.

They say that the system will prove very attractive to Food and Drink plant operators that currently discharge their wastewater to sewer.

Where this is the current disposal method they say that NVP Energy can significantly reduce the high trade effluent discharge costs that arise from the application of the “Mogden” calculation of TE Charges due to high chemical oxygen demand (COD), and total suspended solids (TSS) attenuation.

I spoke to Tracey Giles (NVP Energy, Design Engineer) who said:
“For Food and Drink plants that treat their wastewater on-site, NVP Energy can considerably decrease their aeration costs. In addition, the Lt-AD technology can reduce organic sludge volumes by up to 90% when compared to the activated sludge process thus reducing sludge management costs.”
“The technology is very attractive as it has produced effluent which adheres to effluent release standards, e.g. Urban Wastewater Directive (UWWD) COD release standards, without the need for post-treatment. This is proven from our pilot-scale trials using our “low-strength” effluent definition, a type of effluent that will apply to very many businesses”.
Benefits of Lt-AD are listed as:
  • Significantly reduced OPEX due to lower discharge costs through a high COD attenuation (approx. 80% removal rate) capability & reduced TSS levels (approx. 50% removal rate).
  • Reduced OPEX - up to 90% less organic sludge produced than the activated sludge system.
  • Energy Efficient - No WW heating or aeration required. Lt-AD has been successfully trialled at temperatures as low as 40C.
  • Potential savings from biogas production – can be used to generate electricity/heat that will offset use of fossil fuels.
  • Potential revenue from biogas production - FITs/RHIs for on-site energy generation.
  • Modular design allows flexibility in WW volumes.
  • Integrates easily with existing WW treatment systems.
  • Aids in adhering to specific discharge requirements e.g. UWWD.

Summary:

NVP Energy offers an exciting new and innovative energy-positive, low temperature anaerobic digestion technology (Lt-AD).

Lt-AD treats wastewater (WW) highly efficiently at temperatures as low as 4°C and will significantly reduce low strength wastewater treatment costs and TE charges. The Lt-AD technology target markets are Food and Drink WW including Dairy, Brewing, Malting and Distilling applications; Municipal WW; certain pharmaceutical WW streams and also ethanol processing WW.

For more information visit: www.nvpenergy.comhttp://nvpenergy.com

Tuesday, August 12, 2014

New Schmack Carbotech Plant to Shows Extent of Swedish Commitment to Biogas Biomethane Production

Shmack carbotech biomethane upgrading
Schmack Carbotech Stockholm: Sweden’s role in bioenergy production, with the world's largest installed biogas upgrading capacity, is set to continue its march toward transport fuel sustainability ahead of other nations. That is because of the announcement that Schmack Carbotech has been signed-up as the "design and build" contractor for a 2000 Nm³/h biogas upgrading facility to be located to the south of Stockholm.

Schmack Carbotech’s innovative Pressure Swing Adsorption (PSA) technology will be used in a development that will enable the Swedish capital to produce pure methane (biomethane) from more biogas.


(Image: (c) Schmack)
This will increase the proportion of biomethane, it uses by 50%, this will provide biofuel for vehicles currently powered by natural gas. The biomethane produced will be a high purity gas leaving the PSA with a methane content in excess of 97 per cent.
Fed by organic waste and waste kitchen oil, the plant, which will be located in Sofielund, Huddinge, will produce biogas with an annual energy yield of nearly 100 million kilowatt hours. That's enough to supply approximately 5,000 vehicles clocking up an average of 20,000 km per year each.

Part of the Viessmann Group, Schmack Carbotech’s Pressure Swing Adsorption (PSA) principle distinguishes itself from other technologies because of its favourably low energy consumption, efficient heat extraction and high methane yield, as the company’s International Business Manager, Eberhart Wusterhaus Gomez, explains:
“This important new contract at Sofielund brings to bear all of our 30 years ‘experience in the development, engineering and manufacturing of turnkey gas upgrading plants.
“As industry pioneers and market leaders in biogas purification, we are very keen to play our part in delivering a low energy yet high yield technology that in this case fits in perfectly with the Swedish government’s long-term thinking to become the world’s first completely oil-free economy”.

(Image: (c) Schmack)

Setting new standards in biogas process efficiency, Sofielund’s new plant will be equipped with a CNG station, a Carbotech PSA plant, off-gas cleaning with high heat recovery system combined with a peak load boiler. The plant will also benefit from ultra-reliable VOC and Hydrogen Sulphide removal, making Carbotech’s robust technology ideal to produce biomethane from biogas, sewage gas and landfill gas for grid injection and CNG vehicle fuel. As well as being a specialist in upgrading biogas plants, the Viessmann Group is actively implementing complete biogas turnkey solutions worldwide. Installations include award-winning biological technology, with special wet fermentation (from Schmack Biogas) and batch-dry fermentation (BioFerm technology) now integral parts of more than 300 cogeneration and biomethane plants in Europe and beyond. This includes Europe’s largest dry-AD-from-organic-waste plant, located in Fife, Scotland.

The Viessmann Group is a leading international manufacturer of heating technology systems. Founded in 1917, the family company has around 11,400 employees with group sales of EUR 2.1 billion. Viessmann has an international presence with 27 production companies in 11 countries, sales companies and representations in 74 countries and 120 sales branches worldwide. 55 percent of sales are generated abroad.

For more information, contact:

Press:
Petra Krayl
Schmack Biogas GmbH
+49 (0) 9431 / 751-285
petra.krayl@schmack-biogas,com
www.schmack-biogas.com






Thursday, July 31, 2014

Lukeneder Offers Biogas Plant Owners a Leap in Biogas Plant Efficiency

http://images.anaerobic-digestion.com/meme/view/Biogas Plant Efficiency - Iron Additive Dosing/53d2d3b33111e
The German Company Lukeneder recently added the UK to its list of countries to which it supplies its Deuto-Clear® Sulfo product, which is an iron dosing chemical. That means that UK anaerobic digestion plant operators can now obtain substantially improved biogas plant efficiencies, and raise the profitability of their operations.


View this description of the Lukender Deuto-Clear® Sulfo product on YouTube.

The Anaerobic Digestion industry tends to spend too much time scrubbing the biogas, when in most cases, a far better solution to producing a better quality of gas, is to tackle such problems at the source of the problem, in the digester. By doing it in the digester there are so many spin-off benefits. In fact, operators will end-up wondering why they did not previously pursue all avenues for optimizing the conditions in the reactor to suit the micro-organisms they want to encourage!

A policy of H2S prevention, combined with the avoidance of high (and biochemical process inhibiting) ammonia concentrations, not only helps to stabilise the whole methane production process, it also allows the healthier biomass that results, to produce more gas of a better quality. This is achieved, it is understood, without changing the feedstock, and occurs over a period of time.

This looks like a true “win-win” situation, and involves the daily dosing of the digester with Deuto-Clear® Sulfo. This according to the Lukeneder brochure:

"Is a ready-to-use solution containing metal salts and trace elements. It improves the performance of your biogas plant and its dosage will be adjusted to fit the specific needs of your digester. Deuto-Clear® Sulfo features a broad range of trace elements, minerals, and other agents to improve the quality and stability of the digestate."
Deuto-Clear® Sulfo removes hydrogen sulphide and ammonia gas from the digestate and adds nutritious trace elements and minerals to produce a healthy and productive environment for anaerobic bacteria.
 Added benefits are listed as:
  • HOMOGENISATION OF FERMENTATION SUBSTRATE
  • QUALITY OF FERTILISER IS IMPROVED AS AMMONIUM
  • AND SULPHUR COMPOUNDS ARE BOUND IN THE DIGESTATE 
  • NO LONGER NECESSARY TO DOSE WITH OXYGEN TO CONVERT H2S.
To read our more comprehensive article go here.

For more information and copies of supporting documents contact:

Dr. Naoimh McMahon, UK Representative, Lukeneder GmbH (BIOGAS & ANIMAL HYGIENE)
Telephone: +44 (0)20.3151 0883
Email: naoimh.mcmahon@lukeneder.com
Internet: www.lukeneder.com

Wednesday, June 25, 2014

How to Stop Water Pollution Risks Leading to Water Pollution from Biogas and AD Plants

There was recently quite a serious UK biogas plant digestate tank failure at Harper Adams University recently, which we reported on in our last post. It led to digestate leaking into a bunded area, and because the right precautions were taken with containment it is extremely unlikely that any pollution has occurred.

That led us to consider what we could do to help those people who are responsible for Anaerobic Digestion and Biogas Plants to understand the UK legislation on watercourse and groundwater protection. Most will be familiar through their site environmental permitting arrangements anyway, but we wanted to provide an accessible reminder which would also be useful to our international readers who might view it as "good practice" worth following, even if similar local regulations don't exist in their location. 

The idea is that a better appreciation of the law in this area, and what causes most spillages, should help to ensure that those responsible, such as site managers and plant operators carry out what is in fact their legal duty (in the UK). That is to assess risks from their liquid storage installations and reduce all such risks to their minimum which in most cases (as for anaerobic digestion plants) means providing suitable containment.

The answer, we thought, would be to post the infographic image below which is based upon a UK Chartered Institute of Waste Management Fact File.

It provides the legal basis for compliance by owners/ operators of factories and other potentially polluting sites, making sure that they appreciate their legal liability should they fail to follow the guidance. It then provides a summary of some of the most important requirements for minimizing pollution risks from processes like anaerobic digestion, where collapse or even a leak can harm large areas of groundwater, or long stretches of rivers if either the mixed-liquor, stored digestate, or even uncontrolled maturation slab run-off reaches rivers, or soaks into the ground and into the groundwater.


test
Share this with your friends:
Want to link to this page? Here is the link: Embed this on your site. Just copy and paste the code below... (Replace [website] with http://visual.ly)

ShareThis Copy and Paste
Here, in text, is what the CIWM said in their Fact File:

OPERATORS OF permitted facilities are responsible for complying with their environmental permit and for preventing pollution of air, land and water.
Waste management facilities have the potential to cause significant environmental harm, which could threaten water supplies, public health and wild life in the event of an environmental incident such as fire, explosion or spillage.
 A facility found guilty of causing a pollution incident could face a fine of up to £50000 in the Magistrates Court.
In order to prevent environmental harm you should be aware of the following:
The source of the contaminant;
  • the most common pollutant in the UK is oil 

The pathway 
  • this could be the site's surface water drainage system or via off-site surface drainage, direct run-off, foul drainage system or into the atmosphere 
The receptor
  • ie a river, groundwater, the local population. 

Potential causes of environmental incidents include: 
  • delivery and use of materials 
  • plant or equipment failure 
  • containment failure 
  • fire, explosion or failure to contain fire fighting water 
  • wrong connections of sewers and pipes 
  • discharge of partially-treated or raw effluent 
  • vandalism 
  • flooding of part or all of your site.

Those operating waste facilities need to assess the risk from every one of the above listed potential causes, in the context of the source (degree and nature of pollution), the pathway to the permeable ground, river, ditch or stream which would become the receptor

Wednesday, May 07, 2014

Poo Power Infographic Taps Into Public Sensitivities About Biogas from Waste in Our Latest AD Blog Post

This post is about another web page, which we hope that you will want to visit. Read-on and you will discover why that is.

Here is the top part of the new infographic from that other page, which we have been given permission to use by Lanes for Drains – Drainage Contractor, through the embedding code they provide below this interesting infographic image, in its original location, on their website.

 From Poo to Power - Via Anaerobic Digestion!

The way the subject is handled won't meet the approval of some people (we apologize if that is you...) as the source of this very clean and environmentally sustainable "energy from poo" is something most of us would rather not dwell upon. 

However, the reason that "Lanes for Drains" commissioned this informational artwork in the way they have done, was very much one of publicizing anaerobic digestion to a new audience by using a novel way to communicate what most would otherwise consider to be a very dry subject.

If you visit our web page at http://blog.anaerobic-digestion.com/sad-engineers you can see the full infographic which is unfortunately simply too large for us to embed it here on this blog page!

Below the infographic which tells the story of the growing number of (sewage sludge waste fed) Anaerobic Digestion Plants around the world, we have added a YouTube video which we really liked because it shows an experiment which demonstrates just how well a digestate culture can produce biogas in a simplified biogas reactor system.

It is just the sort of "hands-on" chemistry experiment which inspired me when I was at school and hopefully it will inspire many youngsters to consider studying science.

More and more schools are teaching children about how anaerobic digestion produces biogas and indeed GCSE teaching in the UK about biogas includes a course-unit in which it is explained. So we hope that this page will help continue that trend. More and more demonstrations of the unique combination of chemistry and biology which creates this useful, mostly methane (biogas) power source can only mean that the take-up of AD will grow further.

We are hoping that our page at the Anaerobic Digestion blog (see link above) will be seen very widely, so any help you can give when you go and check the infographic out. by "Liking" or "Sharing" the page using the buttons that we have provided, would be greatly appreciated. Now if you visit http://blog.anaerobic-digestion.com/sad-engineers I'll see you there!

Thursday, April 24, 2014

Recent Biogas and Sewer Methane Explosion Incidents Worldwide

Thankfully, as far as we are aware, there have been few methane explosions reported recently worldwide, which is good news because there have been deaths in the past when biogas has exploded.

There was an explosion in India at the start of 2013 which caused at least one death, which was reported as follows:

ᔥTwo labourers killed in Maharashtra gas explosion

Solapur (Maharashtra) : Two labourers were injured, one critically, in an explosion at a biogas factory while it was being constructed on the outskirts of the city, police said.
"Some labourers had undertaken drilling and welding work near a cement tank at the upcoming biogas plant Solapur Bio Energy Pvt. Ltd. However, they did not know of the gas in the tank," an official from Solapur's Jodbhave police station told IANS.
"An explosion took place after the gas leaked out due to drilling and welding near the tank. Two labourers have died and one is critically injured with severe burns," the official added.
Read more here.

There has also been an explosion in China, which was reported on March 30 2014, as follows:

ᔥBiogas explosion erupts in Xiamen sewer, no casualties reported

“The food stall was burning coals to cook soup in a pottery jar by the door at that time. Maybe its coal fire splashed into the sewer and caused the explosion,” he explained. However, the cause of the biogas explosion has not been confirmed. The case ...
A sewage gas explosion erupted in a sewer on Siming South Road in Xiamen on Friday morning, terrifying many residents around the site after hearing a loud bang caused by the explosion.

The explosion that occurred at 9:30 am has been brought under control. No casualties were reported, but the glass door of one nearby store and a section of the street was heavily damaged.


According to the work safety supervision bureau, the area of Siming South Road near the explosion is filled with food stalls. These stalls often dump their sewage and waster into the closed sewer, which easily produces a large quantity of highly flammable methane gas. 
Credits: Biogas explosion erupts in Xiamen sewer, no casualties reported - What's on Xiamen

Then there was our own report, on our sister blog, of on anaerobic digestion plant biogas explosion back in March of last year, which we wrote about :


ᔥAnaerobic Digester Plant Explosion

Nobody was hurt by this biogas incident...
Credits: Anaerobic Digester Plant Explosion Blamed on Gas Storage EPDM ...

Of course, if we look back in time a little further, there were the following biogas explosion incidents:

ᔥFour die in biogas plant explosion in Ernakulam

Aug 27 2009: By TwoCircles.net Staff Correspondent,. Kochi: Four people were killed and several others injured when a biogas plant exploded at Aluva in Ernakulam yesterday. About six people are reported to be missing. The explosion ... 
Credits: Four die in biogas plant explosion in Ernakulam | TwoCircles.net

And finally:
Investigators believe the powerful explosion that rocked Kirinyaga Road on Sunday was caused by biogas from an underground room of a petrol station.
Credits: Biogas in room likely cause of city explosion, say ... - The Standard
 
If any of our readers know of other recent biogas explosion incidents, please use our comments facility below to tell us what you know. These incidents need publicizing so that the both biogas businesses and the health and safety authorities responsible globally, never forget of this danger.




Friday, March 28, 2014

Removing CO2 from Biogas - Carbon Dioxide Scrubbing Methods and the Eco Benefits from Upgrading

http://images.anaerobic-digestion.com/meme/view/How to Eliminate CO2 from Biogas/53357d78cfee7
Biogas can be upgraded (purified) to natural gas distribution pipeline quality for use as a renewable natural gas, but as part of the upgrading process, it will be necessary to remove the carbon dioxide (CO2) from the biogas. 

This upgraded gas may also be used for residential heating and as vehicle fuel, so there are many good reasons for removing the CO2. CO2 will always be found in biogas due to the fact that during anaerobic digestion, (i.e. degradation in the absence of oxygen), organic material is decomposed by bacteria forming a mixture of CO2 and CH4 with trace amounts of H2S and water vapour at saturation pressure. 

Common methods used to eliminate CO2 from biogas are: - water scrubbing - membrane systems - pressure swing adsorption (PSA) - chemical CO2 absorption - amine gas treatment - CO2 by cooling and recovering dry ice. These systems also generally reduce the H2S and H2O content. Biogas treatment systems, also need to include feed compression on the un-pressurized raw biogas.

Trace components that are often present in biogas are water vapour, hydrogen sulfide, siloxanes, hydrocarbons, ammonia, oxygen, carbon monoxide, and nitrogen. Pressure swing adsorption (PSA) systems, can be thought of as being molecular-sieves for carbon. PSA has been described are the second most commonly used biogas upgrading technology in Europe, after water scrubbing which is most likely the most popular. A typical system is composed of four vessels in series that are filled with adsorbent media which is capable of removing not only the CO2 but also water vapour, N2, and O2 from the biogas flow. 

Typically the PSA upgrading takes place over 4 phases: pressure build-up, adsorption, depressurization and regeneration. The pressure build-up occurs by equilibriating pressure with a vessel that is at depressurization stage. Final pressure build-up occurs by injecting raw biogas. During adsorption, CO2, N2, and O2 are adsorbed by the media and the purified gas discharges as pure methane to a quality which will be far less corrosive and has a higher calorific value.

Recently developed gas-liquid membranes have been introduced, which operate at atmospheric pressures thereby reducing the energy consumption of compression. The use of specific solvent solutions allows the separation and recovery of the H2S and CO2.

 Another approach to improving the economics of gas upgrading has been to recover the CO2 by cooling and recovering dry ice. This can then be sold as an industrial gas whilst the biogas is either used in its more concentrated form (80-90% CH4) or further refined to vehicle quality standard (>96% CH4).

 An example of membrane use for the elimination of CO2 from Biogas follows:
"Silicone (PDMS) has a very high permeability to CO2 compared to methane. This difference in permeability facilitates the transfer of CO2 preferentially over methane, thus enabling the removal of CO2 from a natural gas stream.
Similarly other contaminants such as hydrogen sulfide (H2S) and water (H2O) can be readily removed from methane. The separation factor for CO2/CH4 is approximately 3 for a 50/50 gas mix, indicating that the ratio of the mass fraction of CO2 to CH4 in the feed/retentate is three times smaller than the ratio in the permeate.
Natural Gas purification is simple and straightforward. The feed gas is supplied to one side of the membrane though the feed port, and depending on the feed pressure, a vacuum supply to the opposite side of the membrane may be necessary at the permeate ports.
The contaminants with higher permeability than natural gas will permeate the membrane much faster than the methane, thereby stripping the feed from these contaminants. The high purity natural gas will exit at the permeate port. The permeate can be vented or flared as necessary."
Mongabay News, Pre Combustion CO2 Capture

Why It Is Green to Eliminate CO2 from Biogas?

The purification of biogas for higher-value applications, such as vehicle use or pipeline-quality, is established to be in general a more sustainable and environmentally friendly option than the conversion of the energy to electricity as the energy losses from power generation and the transmission losses for electricity are in general higher than for direct uses of the gas as fuel.

Also, the AD Process is uniquely able to produce transport fuels, whereas other renewable energy sources such as wind turbine, and hydro-power don't, which suggests that it is best utilized to meet the demand for transport fuels.

The energy efficiency for transport fuel use of upgraded biogas is particularly good where the upgraded gas is used to fuel vehicles working on the came facility, or operating from the same facility. The technology for biogas upgrading is relatively new and improvements to the upgrading processes are ongoing to reduce methane losses and improve energy efficiency.