The Food and Beverage Industry accounts for the maximum footprint of water vis-à-vis any other industry. It is the most extensively used raw material in the food & beverage industry. In the manufacturing process of food & beverages, water is used as a processing element. It can also be used for cooling and steam generation, cleaning purposes, or even final product components. A vast amount of input water is produced as highly polluted effluent, necessitating extensive treatment before safe disposal.
In the F&B industry, there are multiple sub-sector industries which include water-intensive products like soft drinks, brewing, meat production, and fruit & vegetable processing. These productions lead to vast amounts of wastewater streams which have high levels of pollutants particularly organic material, as indicated by high measurements of Biochemical Oxygen Demand (BOD) and/or Chemical Oxygen Demand (COD). In many wastes, the value of BOD and COD can reach thousands of milligrams per litre, and in certain productions like cheese, winery and olive milling, it can thousands of COD.
As a result of rising water demand and wastewater production, this industry has a highly adverse impact on the environment and economy. With drinking water becoming increasingly scarce, the reuse of wastewater streams has emerged as a major economic and environmental problem. Thus, it is essential to employ treat wastewater and make it optimal for reuse in the food industry. There are numerous sustainable practices to follow for treating wastewater efficiently. However, there are multiple associated with wastewater treatment in the food and beverage industry. Let’s first understand these challenges and then further find out the best practices for sustainable wastewater treatment.
In comparison to other industries, the wastewater which results from the food & beverage industry is quite different in multiple aspects. Firstly, the volume of this wastewater is multiple times that of others, and as we mentioned above, it has a significant amount of organic content, while in the industrial wastewater streams, there are profound toxic chemical contaminants. But the most noteworthy differentiating factor in wastewater of food & waste is its variability. Seasonal changes, production increases/decreases, product and production line modifications, kettle wash-outs, cleaning operations, and other sporadic variations are all common in food and beverage manufacturing operations, and they all have the potential to cause sudden and significant changes in the volume or character of waste streams.
In the aerobic and anaerobic biological treatment system, the living microorganisms break down and remove contaminants & impurities. As these microorganisms ( collectively called biomass or biofilm) require a stable and suitable surrounding for purification, any variation in the process conditions or waste stream characteristics can act as jeopardy in this biomass health. Thus, the major challenge associated with the wastewater produced by the food & beverages industry lies in its variability. Here are the other major challenges:
The biological treatment systems are designed to handle a particular amount of biodegradable contaminants i.e. BOD and COD. In the food & beverage industry, the BOD and COD rise during seasonal changes in waste stream content, production line changes, or a sustained increase in overall processing volumes. The excessive BOD and COD volume can damage the biomass. There are other symptoms of BOD/COD overloading:
Thus, it becomes highly important to prevent BOD/COD overloads.
As we mentioned, it is important to maintain and a stable & suitable environment for biomass to perform at peak capacity. The biological treatment systems should be maintained at neutral or a bit alkaline pH i.e. 6.5 to 8.5 for optimal functioning. In industries like dairy, meat and poultry, fluctuations in pH and alkalinity a common thing due to seasonal or weather-related fluctuations in production, batch processing methods, changeovers, or other events. If not regulated, severe pH values below pH 6 or above pH 9 can cause considerable harm and biomass loss.
During treatment, the biomass can produce acids and the plant operator will need to maintain sufficient alkalinity to maintain pH. The sudden increases in the level of organic materials in the biomass can disturb this balance which will result in lower pH and eventual damage to the biomass. In these cases, excess acidity can often be managed by the controlled addition of alkaline solutions, such as magnesium hydroxide, potash, or caustic soda.
On the other hand, there can be excess alkalinity due to ammonia constituents which results from animal waste by meat and poultry production. If the pH levels are higher than 8.5, it can be toxic for the micro-organisms used in biological treatment systems, and can quickly kill off the biomass. This is especially risky for anaerobic wastewater treatment systems, where biomass might take weeks or months to restore.
The biological wastewater treatment plants are highly sensitive to temperature and must be operated within specific temperature conditions. Generally, it is 59oF to 104oF for mesophilic populations, but the ideal temperature depends on the microorganisms used for wastewater treatment. If the temperature is too high like more than 104o F, the biomass can quickly be damaged.
Regulating temperature is highly challenging for wastewater treatment plants because they may be located in climates with significant seasonal temperature changes.
The wastewater treatment methods can be biological, chemical, and even non-chemical. E.g. chlorine disinfection is a popular chemical method but it comes into criticism due to its toxicity concerns. We will go through all the best practices for treating wastewater in the food & beverage industry:
Reverse Osmosis is a highly popular term in the water cleaning process whether for domestic or industrial purposes. In this process, a semi-permeable membrane is used to remove ions and unwanted impurities. It can remove both chemicals and bacteria and yield potable water safe for food and beverage production. The permeable membrane filters contaminants via size exclusion, which prevents particles of a given size from passing through.
When impurities or contaminants are dissolved in water, certain ions are formed. In the ion exchange (IE) treatment, these unwanted contaminants are removed and replaced with non-harmful substances. Ions can be positive or negative, and the replacement substance must have the same electrical charge. It should be noted that ion exchange is a versatile therapy that may remove a wide range of pollutants, including beneficial ones.
In the activated carbon filtration process, water is passed through activated carbon, attracting and retaining contaminants on its surface. This filtration process dissolves radon, minimizes the quantity of lead, and removes solvents, pesticides and industrial wastes. It should be noted that the activated carbon filtration process doesn’t remove metals, nitrates, or microbial contaminants.
If there is dissolved oxygen in the water, and if it is left untreated, then it can cause severe corrosion to the plant equipment. In the deaeration method, the dissolved oxygen and other gases get removed from the water. In deaeration, the steam is fed into the bottom of the deaerator where it connects with water. The water is then heated up until the gases dissolve and release out.
In the settling mechanism, a tank is used to remove suspended particles from the water. These particles have a higher density than the water and thus fall to the bottom of the tank. By this process, the physical impurities like fats, greases, hair, sand, grit, wood, and sludge get removed. These impurities which get built on suspension tanks should be discharged regularly.
The ultraviolet rays come from the sun and are invisible to the naked eye. They are an effective water treatment option because of their germicidal properties. The UV rays can disinfect water from almost every microorganism, like bacteria, viruses, and even protozoans. UV light is a popular way of purifying drinking water for domestic purposes.
The membrane technologies have seen significant growth in treating food wastewater. These technologies can remove solids, chemicals, and other impurities from wastewater, mostly based on ultrafiltration or microfiltration. Let’s go through the different membrane-based technologies for treating wastewater:
The membrane bioreactor (MBR) processes have been highly effective in removing organic and inorganic impurities from wastewater. MBR is highly used due to its reliability, scalability, lower sludge generation, high efficiency, operation simplicity, and smaller footprint. The membranes are integrated with the biological step either as an MBR or a Membrane Aerated Biofilm Reactor (MABR). The membranes feature extremely small pores that allow water molecules and dissolved compounds to pass through while keeping suspended particles, bacteria, and other microbes in. In the MABR process, the membrane is not used for filtration but for diffusing air or oxygen into the bioreactor in the molecular or bubbleless form.
Pressure-driven membrane filtration is a renowned method of wastewater reclamation as it comes with a slew of benefits, such as easy installation, rapid execution, and higher efficiency. In this process, the feed stream is put into a filtration unit with a membrane panel, and the needed pressure is applied directly during the operation to separate the permeate and retentate solutions. Membrane rejection behaviour is especially important in this type of operation because it removes large amounts of organic matter, micropollutants, and dyestuff from raw effluents, resulting in high-quality permeate water for a variety of applications such as soil/fertiliser growth, toilet flushing, household washing, and garden watering.
This is a thermal-driven process in which a hydrophobic membrane is employed to separate feed and permeate solutions. The variation in temperature throughout the membrane surface causes a difference in vapour pressure. As the membrane is hydrophobic, it allows only vapour to pass through, leaving liquid on the feed side and preventing it from reaching the membrane pores. The MD process can be performed at less pressure and temperature than the feed solution boiling point. It also demands less vapour space and can utilise low waste heat.
Electrodialysis or ED is a proven method for desalination of water, acid and basic production, and can reduce toxicity and separate ionic and non-ionic species from industrial effluents under the influence of electric potential. When compared to RO, the ED process exhibits a higher rate of water recovery, lower operating costs, simpler operation, and membrane stability. Because ED technology is cost-effective and efficient when applied to water effluent, it has therefore caught the attention of scientists.
FO is an emerging water treatment technology which has received a lot of attention from both academic and industrial perspectives. In FO, the water is passed from the feed solution to the drawing solution due to osmotic pressure difference via a semi-permeable membrane. Thus, in this operation, there is no need to apply physical or hydraulic pressure. In the osmotic process, water is shown to permeate through the FO membrane from the feed solution to the draw solution during the osmotic process when the feed and draw solutions reach equilibrium. As a result, the feed solution is concentrated while the draw solution is diluted.
Wipro Water is a reputed and reliable partner in delivering sustainable and comprehensive wastewater treatment solutions specially curated for meeting the varied needs of the food & beverage industry. We have highly advanced technologies that can efficiently treat wastewater for reuse. Our innovative water treatment technologies remove toxins and impurities from water sources, allowing us to satisfy the highest quality standards for food and beverage manufacturing. We provide tailored chemical treatment programs to ensure the efficiency and dependability of cooling towers and boilers, extending equipment life and lowering operational costs. Contact us today to learn more about how Wipro Water can tailor solutions to your specific needs.