Opinion: Efficiency equals profitability
It is no secret within the anaerobic digestion (AD) industry that in some areas food waste is in short supply. However, if crops fail to perform as expected, on-farm agricultural AD plants will also feel the pinch.
Following this year’s cold snaps and prolonged dry periods in the UK and Northern Europe, arable farming is facing significant challenges. Most crops are less advanced than usual for the time of year, and early reports show that wheat is failing to fill out as expected. Those concerned about feedstock shortages should be looking for ways to plug the gap before the situation becomes critical. This might involve finding alternative sources or types of feedstock, or exploring ways to make plants more efficient and, therefore, more profitable.
Of course, aiming for greater efficiency should not be reserved for crisis situations – there are many ways to improve gas yields and income. Some of these require external advice; others can be implemented relatively easily on site. As part of the AB Agri group, which specialises in agriculture, Amur has experience in nutrition for both livestock and AD. We frequently encounter AD operators that approach feedstock with an eye to volume, rather than nutritional quality, and even many of those plants that operate to full potential could do so in a more cost-effective way.
Gas is king and, therefore, testing for likely levels of gas from feedstocks is critically important. Fast, accurate analytic tools are crucial to enabling AD operators to take advantage of feedstocks on offer – before they are sold to someone else
Biological BMP
Biological BMP (biochemical methane potential) tests rate feedstocks to give operators a potential gas yield. BMP testing comes in three different forms. The biological test reflects the behaviour of bacteria in a live AD, while theoretical testing measures the individual components before apportioning a hypothetical gas yield. Amur’s Bullet BMP technology uses near infra-red spectral analysis to identify the components in a sample. The findings are calibrated and benchmarked against known biomethane potential from a range of waste materials, then mathematically calculated and converted into BMP. The results are significantly more accurate than the theoretical, improving the decision making process when a result is required quickly.
Spectral analysis
Up to 70% of on-farm ADs buy in crops from other farms. Dry matter varies enormously and, since higher levels of dry matter translate into greater gas yields, it is common practice to price feedstock relative to dry matter. While BMP testing takes place in a laboratory, AD operators also need a fast, on site tool to assess incoming crops. Hand-held spectral analysis tools give prompt, accurate results, which may even extend to nutritional parameters such as starch and sugar.
Once feedstock quality – and dry matter – have been established, operators can be comfortable they are paying a fair price, managing feed more effectively, and optimising gas production.
Alternative feedstocks
Sourcing additional feedstocks will provide volume and, in some cases, enhance biology. It is possible to blend feedstocks strategically – for example, adding rice bran to forage maize will increase gas yields. There may be an extra cost associated with this, but it is important to remember that gas yield generates income, so extra outlay may still result in a worthwhile payback. Operators can source feedstocks themselves, or call in expert knowledge. Permits and subsidy allowances will dictate which feedstocks are allowed, which adds another dimension to the selection of the right type of feedstock.
Fine tuning
Just as in dairy farming, trace elements are extremely important in the performance of AD. The addition of enzymes can counteract gaps in feedstocks, and even improve gas output, equivalent to adding an extra couple of tonnes of silage. Again, the first step is to analyse current levels.
The importance of diet, and maintaining a healthy biology are well known within the industry, but operators still struggle to maintain consistent gas production. Amur’s ultimate aim is to generate gas – as much gas as we can – and to enable our plants to achieve this using all the tools available.
This article was written by Nigel Lee, General Manager at Amur.
Amur will be exhibiting at the UK AD and World Biogas Expo at the NEC in Birmingham in July
