Water is a critical resource for food and beverage manufacturers. As with any resource, effectively managing and conserving the usage of water can lead to significant sustainability benefits and operational cost savings.
Easier said than done, getting water right can also be difficult for food and beverage processors. Different production processes have different water quality needs, with costs and even availability of water varying widely across the country. Solving the water puzzle for your facility is an ongoing exercise that can yield major competitive benefits.
When talking about water, we start with the topic of production water and move through the process as it turns into wastewater and creates another set of challenges. Wastewater must be disposed of properly, with careful attention paid to environmental regulations that define the constituents allowed and in what concentrations. Keep in mind that access to and the availability of municipal treatment capacity is not always guaranteed, either which can add cost and complexity to disposal.
Simply put, effective water management can be a real challenge. For manufacturers who want to save water—and save money—it can also be a time-consuming process to figure out and better understand what they need to know. Here are some fundamentals that manufacturers can build upon when it comes to creating a water efficiency strategy.
Know Your Need
The first step is to identify both the quality and quantity of water needed. For example, your ingredient quality or food contact water has one set of requirements, while washdown or clean-in-place (CIP) water has another, and utility water has its own as well. Sometimes the demand for water also changes, depending on which products are being produced daily or seasonally. Another element is storage, storage needs are impacted by whether you have continuous or batch production processes. Every variation in the product or the process creates a new data point to better understand the total water needs of a food and beverage processing plant.
On the wastewater side, the challenge is the same, but a different data set is needed. What are the sources of wastewater and how do their volumes and concentrations differ? Are there different discharge choices available? How clean does my wastewater need to be for each one and are there limits to what chemicals I can add to achieve those goals? Thought should also be put into future permit limits if your permit is due to change, with consideration given to emerging contaminants like PFAS (considered a “forever chemical”).
“You’ve got to get down to unit process demand to get the full picture” says Barry Reicker, vertical market manager, Evoqua. “Efficiency is about correctly sizing the solutions, prioritizing the areas with the greatest cost to benefit and doing so in a way that doesn’t create headaches for your future self”.
As you fill in those variables, a clearer picture starts to emerge. Once you have a good understanding of what your water needs are throughout the process, then you can start to identify opportunities for savings, in terms of both water consumption and the OPEX of your plant. By overlaying your process and regulatory requirements against your sources of water, including wastewater, you can then identify the areas where you can and cannot cut back on water usage. At which point, you can then start exploring how to approach those areas where you can cut back on.
“Sustainability goals are defined at the corporate level but executed locally” says Reicker. In order to achieve an overall reduction in water used, the measures taken at each facility can and should be different. Local variables play a huge role in not only what you do but the order that you do it in. Everything from type and age of existing production and wastewater equipment, to operating costs, water costs, and sources of water need to be taken into consideration. There is often a large educational piece that needs to happen before you get to prioritize and figure out where you're going to execute first.” It is often helpful to grade existing facilities in terms of water efficiency and water costs to help identify which plants to focus on and where within the plant you should begin the review.
As Reicker mentions, don’t overlook the importance of operations when it comes to water efficiency. As with other aspects of efficient operations or sustainability, equipment can be helpful, but it won’t maximize its efficiency if it isn’t operated correctly. Build your educational program from the bottom up to ensure that employees throughout the operation understand the goals of your water efficiency program, the steps necessary to meet those goals and their role in carrying out those steps.
Know Your Cost
Water can vary in price dramatically depending on where a facility is located within a specific country or even state/province. For example, a facility in Pennsylvania will experience one cost, while a facility in Colorado producing a similar product with the same processes and equipment, will have a much different cost structure and availability of water. As a result, some efficiency projects are born out of necessity, cost savings, or done to achieve sustainability goals or any combination thereof.
“After availability, the cost of water versus the cost of a water conservation strategy is a critical piece of the analysis, says Reicker.
“If you're on the West Coast, the cost may become less important, and access to water might be the main concern,” says Reicker. “Without water, best case you’re limiting your production and worst case you're either shutting down or moving your plant elsewhere. So, if you don't have water, conservation isn’t an option, it’s a must. If you do have an abundance of water, then you've got to go through the cost benefit analysis of different water conservation opportunities to figure out if they are worth it and if so, which to do first.”
Sustainability costs don’t stop with the treatment equipment either. Consideration should be given to the types and quantities of concentrates and sludges produced during treatment. Hauling and disposal costs are increasing quickly and often underestimated in the process design stage. If biological sludges are produced, efficient dewatering is an important but often overlooked part of water stewardship. Improved dewatering systems will not only increase the amount of water you can reuse, but also drastically cut your disposal costs.
Building the Case
Building the business case for a water conservation project/program requires making that thorough evaluation of what your actual water needs are and those lines you can’t cross. Your production system and regulatory requirements are going to be fixed based on what you’re making, and you can’t sacrifice either to save money on water. Many times, the low hanging fruit can be found in improving efficiency of existing systems. At later stages of the project more capital-intensive wastewater re-use strategies can be used to achieve the next level of water stewardship.
Reusing water is becoming common strategy as food and beverage manufacturers look for parts of the process where water of a lower quality is needed and can be applied. Food contact or ingredient water requires a certain level of quality, with CIP water requiring a lower level of quality. As a result, in some instances water that’s used elsewhere in the plant can go through a filtration system to remove solids or contaminants, then be used for a first or second rinse CIP system, even if it’s not up to potable standards. A similar process can be used for recycling wastewater to boiler feed. As Reicker warns, understanding what you can and can’t do with water reuse isn’t a plug-and-play formula, but rather a case-by-case detailed calculation.
“Sometimes, a plant will want to recycle water to their boiler but not know exactly how pure they want that water to be. There are guidelines to follow, but that is ultimately an in-plant decision. You could go to super high quality and get more cycles for a premium price, or go to a lower quality at a fraction of the price, there is always a tradeoff to be had and what we try to do is help find that sweet spot for each facility”
Another area for possible cost savings is a wastewater management program. This ties in with water reuse, because an effective reuse program cuts down on the amount of wastewater that needs to be sent to the local utility or otherwise removed from the facility. A smaller-scale or nonexistent water reuse program generally means more water has to be disposed of at the wastewater side of the plant.
The cost of wastewater treatment needs to be included in your evaluation when building the case for a water reuse program. You’ll have a cost for incoming water, but also a cost to clean the water either for reuse or before it can go to the municipal system. If you’ve already invested in advanced wastewater treatment like an MBR your cost to get to reuse is going to be much lower than if you are starting from scratch.
Deciding whether to treat your wastewater to re-use quality or a discharge quality is another tradeoff says Mike Jager, senior project manager. It depends a lot on how strong your wastewater is to begin with and what you have for existing treatment equipment, if any.
“Is it worth cleaning the water and reusing it totally or is it better to discharge to the wastewater treatment plant and rebuy the water afterwards?” says Jager. “What are you paying for disposal costs? Are you paying anything to the wastewater treatment plant in a way of surcharges or anything to clean the water further? Then, we see if it's worthwhile to do so in-house.”
The type of treatment process can impact that decision as well adds Barry. We are seeing a growing interest in anaerobic pre-treatment systems for food and beverage processors who like the inherently low operating costs of a system that doesn’t need aeration, sludge handling or dewatering. We like anaerobic systems as a backbone of a well thought out re-use strategy where you can convert most of the COD into renewable energy (biogas) anaerobically with low operating costs. Then, right size polishing systems that have inherently higher operating costs for your re-use needs. That is often the best of both worlds, which in wastewater like anything else is increasingly hard to come by.
The Bottom Line
Evaluating your water usage, cost and where you can conserve water and save money is a fairly involved process. It requires understanding how much water is being used in each part of your process, where you can and can’t make cuts to how much water is required and what your options are for reusing water and treating wastewater. The costs of disposing of sludge, dewatering it and evaluating whether it will be hauled away, applied to land or end up in a landfill, all fit into this calculation as well. Manufacturers can’t just look at water on the front end of the process. The back end is just as important and vital to the success of any water savings program.
That evaluation is the first step to building a water management strategy that ensures you are maximizing how you use your water while minimizing your total operating costs. You may not be misusing water in your process, but if you’re not taking advantage of where you can reuse water, you can still be experiencing a significant amount of water loss that costs efficiency and increases operating costs unnecessarily.
By taking steps to understand how water is being used and what its true cost is, food and beverage processors can take the first step to a comprehensive, and effective water management strategy/program.