Anaerobic digestion of biomass can be of real benefit to some food companies which prepare food products of all types, but these companies often don't appreciate the biomass asset which lurks unseen in the highly organic content of their food processing waste. In fact, until recently almost none of the companies which might benefit from the anaerobic digestion of biomass which they think is a waste product, have optimised for the emerging opportunity for them to save money and often also to gain income from energy production.
Food companies are not only unaware that they can make money from the anaerobic digestion of their biomass but disposing of it costs them a lot of money. These companies are charged for their waste treatment and disposal according to the Mogden formula, which calculates costs according to the volume and strength of their waste water. Like other industrial companies that discharge waste treatment and disposal into the sewerage network, they should make a conscious decision whether to invest in an energy producing anaerobic digestion (biogas) plant.
Anaerobic digestion technology has improved so much in the last 10 years that all food companies with sewer discharges should re-assess whether their continuing to use their existing waste treatment and disposal treatment process is still their most cost-effective way to treat and dispose of their organic wastes (biomass).
The choice of waste disposal methods for any business is usually a matter which is seldom reviewed in any depth within organisations, this omission may continue for decades of years. Decisions made many years ago on the basis of lowest cost in the first instance, are held onto and frequently not analysed afresh, when advances in technologies for waste management and disposal have moved on.
If companies look in-depth at their waste production in liquid and solid forms, look at biomass wastes separately from other wastes, and managers make themselves more familiar with the data on the nature of their wastes (including waste treatment and disposal); a number of options for optimising processes to make the most of potentially valuable waste streams, can often emerge.
Waste separation, water reuse, and anaerobic digestion to produce power are at the forefront of the available money saving and environmentally sustainable techniques which, in may businesses may not have been considered in an integrated manner for many years.
Another factor worth review, is that in the past many companies had an inbuilt culture which led them to carry out their waste treatment in-house. Nowadays management is much more willing to recognise that much senior management time can sometimes be saved, to great advantage, by not undertaking peripheral activities like waste treatment in-house.
Instead, it may be better to develop close partnerships with other businesses which have the know-how to do things better. Also, economies of scale for regional waste disposal specialists may reduce costs through outsourcing waste treatment.
Decisions must also be made about whether waste treatment and disposal treatment processes should be run in-house or outsourced to a competent contractor.
Tip 1. Ensure any review starts with core decisions at the production process level
Blue sky thinking is needed. If from the start, cost savings is the only driver for a company seeking to address cost issues in its waste treatment and disposal operations, many opportunities can be missed.
Unfortunately, the initial driver for a review of waste treatment practices within a business, is usually the realisation that impending production changes are about to trigger higher discharge costs.
However, with many new waste treatment techniques available, a decision for example to invest in a waste treatment and disposal plant may be made in the belief that simply investing in an upgraded version of an existing plant technology will be a straightforward and easy to justify capital cost investment. But, it may not be the optimum solution.
Such narrowly based decisions to do business as-usual and adopt piecemeal changes to how a business manages waste can be regrettable. Simply to build a water treatment or, for example a composting plant, to avoid waste treatment and disposal charges in the future, can be a major opportunity lost.
Successful waste treatment and disposal while also achieving sustained cost reductions involves analysing real data about a plant's waste creation and water-use, from start to finish. The much-neglected aim of waste minimisation should become a company mantra, and an essential component of any solution. But, not to forget anaerobic digestion of biomass options either.
Tip 2. Collect real plant data and collate it in intelligible formats
Ensuring that the decision makers have the facts at hand before investigating waste treatment and disposal is so obvious. a requirement. But, remarkably many managements baulk at spending money on the necessary sensors, and weighing technology, needed to gather this information.
Many organisations assume that to record waste produced and discharged month by month is sufficient. But, such a sparsity of data is almost never sufficient when making major decisions about process requirements. Instead, basic monitoring equipment investments which would provide data which will be needed to optimise the process design are rejected. And yet, the process designer will not be able to simply guess these flows for all days of the week, seasonally, and at other times which will be industry specific. Guesswork will almost never provide the right outcome. Management needs to accept the need for proper data collection. Investments in process flow data collection cannot be neglected without financial penalties later, in running less than optimally designed treatment plants.
Only when management is familiar with the full picture is it possible to understand exactly what the materials balances are on any site. This often involves understanding multiple material flows, both how much water and other (solid) material is coming in, and what volumes and weights are flowing out. Also, for mixed flows, what the water contents are, and what drives water content.
At the same time for more complex processes the decision-makers need to understand where there are intermediate flows between processes. And, where unwanted organic flows can be directed to a facility to provide the anaerobic digestion of biomass.
Most important is Identifying what percentage of incoming water ends up as effluent, the amount of biomass in it, and what happens to it at every step of the manufacturing process.
Only when this is known is it possible to start altering longstanding practices. But the rewards from doing this can be high, especially if there is an opportunity for anaerobic digestion of biomass. They may enable the business to start making significant reductions in waste tonnages, and also water-use savings.
It is almost never that companies have adequate data. But without, for example, a hydraulic profile and an accurate waste flow diagram for the site broken down for busiest days and quiet periods within the working day, there will be design problems. Without this minimum there really is not sufficient information to explore the “what ifs”, and size the much-needed engineering solutions.
Once, a distinct pattern emerges through familiarity with the data, showing how and why biomass and water, becomes waste, the decision makers can move on.
Tip 3. Seek out high waste content streams
Only after a waste analysis has been completed, and the interrelated flows are charted intelligibly does it become possible to focus in on different process options. Some may be responsible for producing highly concentrated waste, or may be re-engineered that way, to implement the anaerobic digestion of biomass.
Keeping concentrated waste streams segregated and uncontaminated by other wastes, can have remarkably positive impacts on total waste treatment and disposal demands. If so, it is often worth considering segregating out highly concentrated waste.
The reason for this is that this waste type can often have a monetary value elsewhere. One option is as feedstock for a biogas digester (anaerobic digestion) plant.
But if not, it can frequently prove cheaper to tanker concentrated waste off-site rather than treat it. It may even be possible to invoke the “circular economy” to find businesses which can use your waste as a raw material for their own business.
Also, some waste streams will generate their own revenue. Fat, oil and grease, for example, can potentially be valuable as feedstock for a company producing bioethanol. It is true to say that one man's waste is another man's gold-mine.
Tip 4. Optimisation of Return on Investment
Treating the minimised residual waste is not just to be thought of as an end-of-pipe cost. Instead, treating waste effectively can provide a valuable return on investment (ROI). Anaerobic digestion, for example, can generate power for the plant. Some of these types of waste treatment and disposal schemes can be more than self-sufficient in energy, with the bonus that any excess can be entered into the grid network.
Similarly, water reuse can offer savings. There are capital incentives available in the UK and tax relief offered on an element of the capital invested if it can be shown to reuse 40% waste. In the Middle East, many plants use waste treatment to produce water suitable for irrigation.
A balance sheet of the costs versus return on equipment or operations, should also include the reduced cost of paying a water company to take the wastewater for treatment and disposal. If the anaerobic digestion of biomass is included, there will be new products such as the energy sold, which will contribute positively to the company balance sheet.
Also, companies should not forget the added bonus of improved CSR (corporate social responsibility), shareholder value, and environmental credentials.
Tip 5. Look at other solutions including for example the anaerobic digestion of biomass
When evaluating the viability of an in-house waste treatment and disposal solution, it is worth considering whether outsourcing the operation of any necessary plant to a third party might be an option.
Sometimes a third party might even see it as being to their advantage to finance the operation.
Some waste treatment and disposal companies are willing to offer financing and operations packages. This can be in a form which entails food companies entering a ‘simple' service agreement, rather than having to make the capital outlay themselves on equipment and/or processes. They may also have expertise which allows the food company to negotiate consent agreements, and ensure legal compliance etc.
Tip 6. Re-assess whether to keep resources in-house
As part of the assessment of what a solution will achieve in terms of reduced effluent and compliance, it is vital to look at the resources available within the business in terms of labour, knowledge, expertise etc. If looking to invest in a certain effluent treatment solution, make sure that the key personnel are in place to run with its implementation, ongoing maintenance and optimisation over time. Also company management needs to consider what competences will be needed to operate the waste treatment and disposal plant now and/ or a facility for the anaerobic digestion of biomass.
Tip 7. Choose a contractor with a track record
Ultimately, when companies are ready to invest in waste treatment and disposal treatment which may include anaerobic digestion of biomass, it's critical that they work with an established contractor with a long track record of operating in the same market place. The contractor needs to understand the varying needs of a soft drink plant, a dairy, or a brewery.
Suitable contractors will be able to provide case histories of reference plants in the relevant industry. Such contractors are best placed to consider all the options available and tailor the most effective solution for the particular application including, of course, anaerobic digestion of biomass.
There is no one-size-fits-all solution on offer when tackling wastes such as waste-water. It's all about going back to basics first, having an intimate knowledge of what the waste profile is of the plant, and finally being courageous to change the way companies work.
For those prepared to put in the investment, and work to collect the right data, and apply that to an in-depth understanding of their waste water and biomass waste issues the benefits can be amazing. If they then partner with an experienced contractor, to deliver the necessary infrastructure such as an anaerobic digestion of biomass facility, there is a lot of opportunity out there.
Article inspired by “Top Tips for Effluent Treatment”, via www.wateronline.co.uk