3 Types of Biogas Mixing Systems Advantages and Disadvantages of Use in ...

Biogas Digester Mixing Equipment

Biogas plant designers will tell you that the main factors that influence the rates (and, therefore, the success) of these biological transformations in the AD reactor are hydraulic and solids residence time (HRT/SRT), temperature, pH and the presence of toxic materials.

But, that omits one other essential requirement which can be left to chance on some occasions, and that is getting the tank agitation, or more commonly called 'mixing". right.

Unmixed, low rate AD reactors will stratify into four zones (layers): Floating scum; liquid supernatant; actively digesting solids; and digested and inert solids. Mixing systems for high rate AD reactors are typically designed to achieve a specified percentage of active working volume, typically defined as the total volume of the reactor minus an allowance (usually 10%) for the floating scum layer, and the inerts layer at the bottom. Mixing systems try to minimize the sizes of these two capacity-stealing layers. Working volumes less than 85 percent are inefficient digester reactors.

More energy is needed to keep heavy solids in suspension than to homogenize the reactor contents. via www.biocycle.net

Exhibition attendees looking at an in-tank propeller type biogas mixing system.

Mixing the digester requires a significant amount of energy, which becomes a parasitic load on the output of energy which can be used on-farm or sold. One possibility to operate biogas plants more efficiently is to reduce the energy consumption by avoiding constant stirring. AD Operators and water companies can reduce the energy usage of their digester pumps and mixers by up to 50%, according to leading manufacturer, Landia. While most operators find this to be the answer to high energy use during mixing, some say they can experience more foaming during intermittent mixing.

An advantage of gas mixing can be that the high velocity gas-liquid jet causes mixing of the tank at a higher level than the hydraulic mixing. The gas bubbles reduce the density of the liquor in the digester. The result of this is that, low-density materials, such as plant fibers that often float to the surface, will be forced to sink into the tank. This can reduce the floating scum on the surface, and be a very welcome result.

Operating an AD plant with lowest possible electricity consumption and minimized OPEX is a key factor in optimizing the total cost over the lifetime of the biogas plant, so the subject of anaerobic digestion reactor mixing is an important one.

Why More Water Companies Should Consider Adding Anaerobic Digestion Wastewater Treatment

The Need for More Water Companies to Add Anaerobic Digestion Wastewater Treatment Facilities to the Sewage Works

The following is an excerpt from the above pdf, which outlines why more Utility companies should consider installing Anaerobic Digestion Wastewater Treatment Facilities at sewage works:

Existing Infrastructure – Many wastewater treatment facilities in the Pacific Southwest (US Region 9) and across the country, use anaerobic digesters to reduce the volume of the biosolids (sewage sludge) before they are taken off-site. The anaerobic digesters produce biogas which is either flared or used onsite as an energy source. Therefore, the energy capturing infrastructure is already in place at many facilities.

Existing Expertise – Wastewater treatment facilities already have the on-site expertise and years of experience dealing with anaerobic digesters; vessels that are difficult to operate without thorough knowledge.

Located in Urban Areas – Wastewater treatment facilities are often located in dense, urban areas, where compost facilities are not. It makes logical sense for a highly-populated area to ship organic waste to a nearby anaerobic digester where the energy content is recovered and the volume reduced. The residual can then be trucked to compost facilities, which are typically located farther from urban areas. via USEPA.

While many local governments and municipalities may be interested in processing food waste in anaerobic digesters at treatment facilities, they may feel that the cost is a limiting factor.

However, there are many things to remember before immediately discounting this technology based on cost.

Payback period: Although the initial costs may be large, the digestion of food waste can be quite lucrative and the payback period can be less than three years depending on the existing
infrastructure at the wastewater plant.

When a facility accepts food waste at a plant, they can charge the waste haulier a tipping fee for accepting the material. In addition, there is a significant amount of money that will be saved in energy avoidance due to methane production.

The excess energy can be sold back to the grid for profit. This article is provided via USEPA.

The full article is here.

Methanogenesis, Synthetic Biology and the Biogas Industry

Methanogenesis or biomethanation in a biogas plant is an important process resulting in the formation of methane. The methane can be collected and used as biogas, a renewable fuel.

Most of this biogas is produced from biomass on farms, but biogas can also be produced during anaerobic wastewater treatment. Wastewater treatment methods include methanogenic anaerobic digestion, and when used this technology results in the production of biogas and clarified effluent.

But, to be effective in producing biogas in quantity, anaerobic digestion needs to be conducted within the ranges which existed for millennia in nature, and these are called the mesophilic and thermophilic temperature ranges.

Methanogenic compositions in biogas reactors and methanogenic communities in reactors are only established in fully anaerobic conditions, and currently only when operated at those optimum temperatures.

But, does it always have to be like this? Could we alter when biogas is made, including make biogas efficiently low temperatures.

There would be massive benefits from this, especially for cold climate regions.

To go any further, let us explain a little about the all-important bugs (methanogens) needed to make biogas:

Methanogens are microorganisms that produce methane as a metabolic byproduct in hypoxic conditions. They are prokaryotic and belong to the domain of archaea. They are common in wetlands, where they are responsible for marsh gas, and in the digestive tracts of animals such as ruminants and humans, where they are responsible for the methane content of belching in ruminants and flatulence in humans.

The methanogenic archaea populations play an indispensable role in anaerobic wastewater treatments. via Wikipedia

To create genetically engineered existing DNA sequences, through synthetic biology would allow scientists to build entirely new sequences of DNA and put them to work in cells.

This would allow the building of novel biological devices that would never exist in nature. This is known as synthetic biology.

Synthetic Biology and the Biogas Industry

Essentially a process operating by living organisms, the biogas industry is a natural target for synthetic biology. In terms of their genetic content, organisms are classified into three natural groups, Archaea, Bacteria and Eukarya. Most microbes are Archaea and Bacteria, while humans are Eukarya.

In an anaerobic digester, many different types of Bacteria convert the complex organic matter in waste or biomass to hydrogen gas, carbon dioxide, formate and acetate. A unique group of methanogenic Archaea then produce the invaluable part of biogas, methane, by eating hydrogen and carbon dioxide, formate or acetate.

One can imagine creating a super microbe to convert the complex organic matter directly into biogas, thus making anaerobic digestion faster, more efficient and easier-to-manipulate. Making a synthetic microbial community by reprogramming key microbes may also help them work together when a tough job (i.e., eating extremely complex waste) needs to be done.

Among numerous microbes in an anaerobic digester, methanogenic Archaea are one of a few microbial groups that have been extensively studied, and a number of genetic tools are available for engineering via synthetic biology.

Therefore, scientists have begun to reprogram methanogenic archaea, allowing them to eat organic matter such as sugars and directly produce methane. If they succeed, they may engineer a super microbe that never existed in nature and revolutionize the biogas industry by making anaerobic digestion much simpler and more efficient.

Concluding - The Huge Potential for Synthetic Biology in the Biogas Industry

Synthetic biology, applied to methanogenesis, holds great potentials to revolutionize the biogas industry.

To achieve this goal, joint efforts between the biogas industry and academia must be made.

The former side needs to understand what synthetic biology can achieve, while the latter side should identify which parts of the process in the biogas industry can be re-designed and optimized by synthetic biology. via BioEnergy Consult

How Manure Management Can Benefit from Anaerobic Digestion

There is significant potential for the anaerobic digestion industry to grow, assuming that the benefits of anaerobic digestion and the biogas it produces are fully appreciated. The anaerobic digestion of manure on livestock farms for manure management is a large possible growth area.

If it meets its full potential, the UK AD industry could meet 30% of the UK's household gas or electricity demand and create around 35,000 jobs, mainly in rural areas where AD plants tend to be located. AD also improves energy security and soil quality, both major government policy objectives, through producing home-grown renewable energy and a nutrient-rich natural fertilizer respectively.

"The UK AD industry has grown by more than 350% over the last ten years and the UK has established itself as a world leader in biogas, with UK companies already exporting biogas-related expertise and equipment. The UK has a real opportunity to be at the heart of the growing global biogas industry, which has the potential to be worth £1 trillion," said Charlotte Morton of the AD industry associations ADBA organisation.

Manure Management Can Benefit from Anaerobic Digestion

The energy produced from anaerobic digestion will come to play a greater role in the global energy mix as countries look to reduce GHG emissions and generate clean energy. The use of anaerobic digestion as a means to utilize organic waste means that it is being incorporated into waste management programmes, to reduce the amount of waste that we either send to landfill or to be incinerated. Through the process of anaerobic digestion, operators can produce a bio-fertilizer, proven to be a cost-effective and environmentally sensitive solution to increase crop yields. The main factors that dictate the potential for an anaerobic digestion market in countries across the world are linked to the availability of feedstock and the state of the regulatory environment.

The numerous benefits of anaerobic digestion to generate clean, baseload energy, improve waste management and produce a bio-fertilize to improve agricultural yields will result in large-scale adoption of the technology, as was seen in parts of Europe in the early part of the 21st Century. Anaerobic digestion facilities continue to receive high levels of investment, proving to be a cost-effective way to utilizing biological waste/organic material to generate energy, as well as achieving significant reductions in greenhouse gas (GHG) emissions.

Digestate can be used as fertilizer and soil conditioner as it contains nitrogen and potassium, both being plant nutrients that can significantly improve growth. It is made from dead micro-organisms and remaining indigestible material during the anaerobic digestion process. It can be used straight from the digester or separated into liquor and fibre.

By using digestate instead of synthetic fertilizers, you can save energy, reduce your carbon footprint as well as decreasing fossil fuel consumption. As none of the potassium, phosphorous or nitrogen is present in the biogas after anaerobic digestion, all of these nutrients are present in the digestate.

Biogas can either be combusted to make heat and electricity or as mentioned earlier, can be purified and pumped into the mains gas grid or used as road fuel. You can find more information on how to use biogas for heat only purposes, electricity only purposes or to create combined energy.

Consumer demand for greener, lower-carbon products and services are on the rise. As a farm business, embracing renewable energy has many benefits.

Not only are farmers investing in the future of our planet with their anaerobic digestion derived energy choice, but they are also appealing to a modern market that is putting sustainability at the top of its priority list. Tie this in with waste reduction, manure management and other sustainability efforts and you'll have a well-rounded plan for becoming and staying environmentally friendly.

Sustainable Food Production A safe, nutritious, and affordable food supply is needed to sustain populations worldwide. Farmers work hard to meet the growing food demand and remain viable in today’s global marketplace. 

Efficiently using water and nutrients for crop and animal needs can cut costs, reduce environmental impacts, and contribute to a safer, more productive farm. Manure digesters on livestock farms can: Protect animal and human health by reducing pathogens. 

Convert nutrients in manure into a form that is more accessible for plants to use compared to raw manure. This can increase crop productivity and yield. 

Recycle nutrients on the farm, creating an economically and environmentally sustainable food production system. 

Produce heat, electricity, or fuel from biogas which can be used on-farm, lessening the agriculture sector’s dependence on fossil fuel energy. 

Accept food waste from places like restaurants and grocery stores. This means less food waste is sent to landfills. 

Food waste has the added benefit of increasing the efficiency of farm digesters.

Bioeconomy – What's the Meaning of it?

Bioeconomy – What's the Meaning of it?

That’s a good question.

Stay with us a moment and we’ll explain with our definition.

Novel new materials made from biology.

Plus, we tell you why it’s good for our planet, and can reduce climate change.

Our planet is getting more and more crowded.

As a result, we need to use our resources more sustainably.

The bioeconomy is making and selling useful things using renewable materials, which means that these are made from organic, carbon-based biological matter, instead of being produced from oil, and are refined in petroleum refineries to make plastics and synthetic fibers.

Most things you buy start out being oil. Even though many people are not aware of it, the bio economy is already part of everyday life.

Bioresource technologies are already being used to replace many goods and processes currently based on fossil fuel resources.

In some cases, bioresource based goods even have novel properties, which can make them superior to the goods we currently depend on.

In short, the bioeconomy means using renewable resources for innovative products, instead of the present oil-based economy.

Today, we depend on fossil fuels for things like clothing plastics and chemicals.

The goal of the bioeconomy is a circular economy producing reusable bio-based products.

Many nations in Europe are collaborating in EU wide research to become leaders in this growing market.

However, most people don’t realize that sustainable alternatives already exist, like the shoes you saw at the start.

We hope we have helped to raise your awareness of the bioeconomy.

Help promote biogas production!

The Bioeconomy Means Facing the Future With Real Sustainable Solutions 

The bioeconomy of bio-based development has actually shown up. Market can easily currently create bio-based plastics coming from vegetation oils as opposed to fossil-based resources. These bio-based plastics could be produced bio-degradable, also in seas, or even they could be produced tough, to substitute glass.

Swift is actually the modifications in scientific research and also production, and also therefore extensive are its own ramifications, that some recommend to the brand-new bio-economy, that utilizes bio-based resources for fairly a lot just about anything in our economic climate, as the 4th commercial reformation.

The cross-cutting mother nature of the bioeconomy offers a one-of-a-kind possibility. A possibility to adequately take care of linked popular problems like meals safety and security, fossil-resource dependency, raw material deficiency. it can also bring forward the achievement of environmental improvement while attaining lasting financial progression.

But, obtaining maintainable bioeconomy progression experiences several difficulties:

The foresight growth in weather disorders and also boosting the deficiency of nonrenewable energy resources need the economic situation to become located ideally on renewable energies. Getting international nourishment additionally requires a rise in performance along with as a result of respect to guarding sources as well as the atmosphere.

Innovative natural and also technical expertise as well as techniques for each but maintainable and also demanding development, arrangement and also handling of biomass might cause this modification in the commercial source foundation. As well as bring about lowering the worry on the atmosphere during climate change, as well as to preserving the planet's limited information.

Therefore, the bioeconomy supplies a potential chance to integrate financial development along with eco liable activity.

To preserve its own competition, Europe is going to need to have to make sure adequate products of basic materials, electricity and also commercial items under ailments of minimizing fossil carbon dioxide sources - oil and also liquefied gasoline manufacturing is actually anticipated to deduct around 60% through 2050.

Bio-waste (predicted at around 138 thousand heaps each year in the EU, of which approximately 40 % is actually landfilled) possesses higher possibility incorporated market value as a feedstock for various other effective processes. Biological sources as well as communities might be made use of in a much more lasting, incorporated as well as dependable fashion.

Meals refuse works with yet another significant issue. A projected 30 % of all meals made in industrialized nations is actually thrown away.

The bioeconomy features major creation, including horticulture, forestation, fisheries and also tank farming, and also sectors making use of and also refining natural sources, including the meals and also pulp and also newspaper markets as well as component of the chemical, biotechnological as well as electricity business.