Agri-food Businesses Could Divert More of their Food Waste to Anaerobic Digestion Plants: Greg Hilton

Bidwells Proposes Anaerobic Solution

Agri-food businesses and householders alike could be diverting more of their food waste to anaerobic digestion plants in order to save on volumes going to landfill and creating a renewable energy source.

Greg Hilton, Renewable Energy consultant for Bidwells Agribusiness said: “We throw away over 6 million tonnes of food waste each year, with the vast majority going to landfill. If we used just 10 per cent of this food waste in AD plants we would be able to supply 50,000 houses with clean, green energy. We would also have a significant impact on our carbon emissions as the food sector is responsible for around 20 per cent of the entire UK carbon emissions.

Diverting food waste from landfill, where it produces the damaging greenhouse gas methane, would make a big difference." The outputs of AD are electricity for use on site or export to the national grid, as well as heat for use in the business or nearby properties, and a rich bio-fertiliser, which could have added benefits for horticultural and agricultural land.

Increases in landfill tax and increased returns from renewable electricity are likely to make AD increasingly attractive in the future. Hilton said: "Anaerobic Digestion offers a win-win situation. It diverts waste from going to landfill, reduces greenhouse gas emissions, and provides high value, sustainable energy.

As energy prices increase, technology develops and pressure mounts to reduce carbon emissions, measures that are green and sustainable become increasingly popular and more viable.

At Bidwells we have…experience in evaluating the technical and economic viability of anaerobic digestion and biomass combined heat and power systems, and we predict that more and more projects will become economically viable over the coming years as margins improve and set up costs fall."

Meanwhile, Leicestershire County Council has recognised the potential value and benefits of anaerobic digestion and is offering support to businesses that would like to evaluate its potential. The council is offering grants of up to £5,000 for a maximum of half the value of an AD feasibility study and is keen to encourage businesses to take up the opportunity. More.

The Role of Hydrolysis for Advanced Digestion

Many of the the companies which have been involved in sewage sludge digestion and are the most experienced in the field are using thermal hydrolysis within their chosen processes. These companies tend to develop their own slant on optimising the hydrolysis stage and to use their own trade name, neverthelsss there is a common reason for doing this and it is to increase the rate of conversion of organic matter, to reduce retention periods within the digester and improve gas yields.

We have uploaded a new page with the title "Hydrolysis, Sewage Sludge and Anaerobic Digestion", to the Anaerobic Digestion Community web site, based upon Veolia's experience with using hydrolysis a part of the digester systems, which provides more information on this.

Sewage sludge digestion has been carried out by anaerobic digestion at some UK sewage works since in the UK sewage sludge first began to accumulate in the new activated sludge type sewage works built from the 1950's in inland areas. However, most of it was simply discharged to the sea untreated until the 1970s including huge tonnages from our large cities. Fortunately, those days are long past with the practice outlawed by the European Union, and ever since then, the huge volumes produced have been treated and disposed of by a variety of methods. All are expensive, and the lowest cost option of discharge untreated to land, brings with it health and soil-metals build up problems, such that its use has to be limited.

As a result, safe and cost-effective disposal of sewage sludge is, without doubt, one of the biggest challenges now facing the wastewater industry. The high cost of energy means that some disposal routes such as incineration which were once favoured are less viable, and others have ceased to be economic.

However, as one technology fades another shines. That process is thermal hydrolysis, and when combined with anaerobic digestion they are a great combination.

Companies such as CAMBI, Monsal, and Veolia Water Solutions & Technologies have recognised this and produced their own proprietary systems. More about advanced AD with hydrolysis.

WU Green Paper on Biowastes Before End of Year

The management of biodegradable wastes will be an important item in the EU waste policy agenda during in 2009.

The European Commission has started work on a green paper on biowastes, which it aims to publish before the end of the current year.

"In this green paper, we want to present the current situation in biowaste management and ask the stakeholders where we need to go from here" - Karolina Fras, an official of the EU Commission's DG Environment, told delegates at the recent annual conference of the European Federation of Waste Management and Environmental Services (FEAD) in Paris.

According to Ms Fras, work on this topic will continue in the year 2009 - for instance through workshops. It might then be possible to table a legislative proposal from the European Commission or other initiatives during the Spanish EU presidency in the first half of 2010.

European Biogas Electricity Production Hits 17272GWh a Year

Date: 29/09/2008
In the biogas field, Germany has built itself a world-leading position. The country built 820 systems in 2006, increasing the total installed production units to 3700 and is now the No 1 world biogas-based energy producer, and also the technological leader.

CIAT plays a major role in this country, with approximately a 35percent share of the market, and has acquired significant know how in gas treatment, enabling it to propose systems adapted to ever widening scopes of application. This concept has brought about specific developments in this field. Two installations produced with the German partners of CIAT, SEVA AG and SILOXA AG, perfectly illustrate this progress.

European Biogas electricity production in 2006 was 17272GWh per year, of which 7338GWh was by Germany alone. Biogas now represents 1.2percent of the annual production of electricity and nearly 10percent of renewable energy, with an installed power close to 1500MW.

In particular, this success is due to efficient regulations, intended to promote renewable energies.

In fact, the German law stipulates the purchase price per kWh by energy distributing companies for 20 years. This price takes into account the ‘green’ nature of the energy and recompenses the operators, based on efficiency, technological innovation and agricultural re-conversion criteria.

During the first year, in certain cases it may reach 0.18E/kWh. This incentive, combined with the power of German industry, makes Germany the most advanced country worldwide in biogas based energy production systems.

There are several different types of biogas production systems. Biogas production always means production of electricity using a gas engine and an alternator.
Process heat can also be recovered. This is called cogeneration. Biogas is a gas produced by the fermentation of animal or vegetable organic matter without oxygen.
Fermentation is also called methanisation and occurs naturally (in swamps) or spontaneously in waste dumps containing organic waste.

Also, it can be artificially produced in digesters (when treating purification sludge, industrial organic waste or selected agricultural crops, etc).

Biogas can also be recovered by sucking mine gas. In all cases, the biogas must be dehumidified and purified before combustion; otherwise it can damage the gas engine.

Biogas is a mixture essentially comprising methane (30 to 70percent) and carbon dioxide, with varying quantities of water and hydrogen sulphide (H2S).

Other compounds can also be found from contamination, especially in waste dump biogas: ammonia, hydrogen, nitrogen and carbon monoxide.

Biogas energy is only produced from methane and is in fact a renewable form of fossil energy, which is natural gas. Furthermore, biogas systems are highly respectful of the environment. In fact, the contribution of a methane molecule (CH4) to the greenhouse effect is 21 times greater than that of a carbon dioxide molecule. Therefore burning methane, even though producing CO2, reduces its impact on the environment.
SEVA has developed forefront know-how for small-sized systems. Out of the 820 installed in Germany in 2006, this company, with a payroll of 150, produced 170 biogas combustion units, with a total cumulative 54 MW power.

The philosophy at SEVA ENERGIE is to make biogas profitable by offering high production rate systems, operating continuously with limited human intervention and very high reliability.

CIAT has become a recognised standard for the up-line treatment part of gas. As previously mentioned, the humidity is removed from the gas. Steam is condensed by cooling the gas to temperatures between 15 and 5°C. The advantage of this process is to eliminate part of the impurities in gas by trapping them in the condensates,which are evacuated.

Proposed Irish Biofuels Obligation Scheme Out for Public Consultation

New target for biofuels in Ireland

Energy Minister Eamon Ryan has published the Government’s proposed Biofuels Obligation Scheme for public consultation.

This scheme will set a percentage target of transport fuels used in the State which must consist of biofuels and sets certain conditions regarding the type of biofuels which can be counted towards that target. The obligation will apply to fuel companies, placing no burden on the taxpayer. It will be a key component in achieving the EU target of 10% penetration of renewable energy in transport by 2020. The Government remains committed to this target.

The consultation document proposes a target of 4% by volume of transport fuel by 2010, equating to 3% by energy. It attaches an important condition - the biofuels must come from sustainable sources.

Biofuels in Ireland must be entirely compliant with EU Sustainability Criteria, which are currently being finalised. These will set out stringent conditions which fuels must meet before they can be considered as contributing to the EU targets, including:-

- a minimum level of greenhouse gas savings
- biodiversity requirements to prevent certain lands such as natural forests and protected areas being used in the production of biofuels - and
- social reporting obligations on the Commission.

The essential aim of these criteria is to ensure that biofuels used within the EU do not result in adverse consequences for societies and the environment globally. They will also encourage the next generation of biofuels and support investment in cleaner and more sustainable types of transport fuels.

The Government’s targets up to 2020 will be continually reviewed as more evidence comes to light on the effects of biofuels in the world food markets and new technologies come on-stream.

Publishing the Scheme, Minister Ryan said - “This new target reflects growing concerns that increases in the amounts of biofuels being produced were having some adverse environmental and developmental effects around the world. We will move towards 2020 with gradual, careful progress.

"However, biofuels remain a fundamentally good idea, given that we need alternative sources of fuel. The era of cheap oil is over and Ireland requires new methods of fuelling our transport fleet.

"Biofuels also remain necessary for Ireland in terms of energy security. We need access to a certain percentage of non-fossil fuel to run essential services, in the event of a global oil shortage. This is prudent planning in an uncertain energy world.