In the food industry, strict hygiene rules apply throughout the complete production process. The standards set in the German Food Hygiene Regulation (Lebensmittelhygiene-Verordnung, LMHV) must be observed both in the production of food and in the cleaning of production facilities. The water used for cleaning the production facilities, for example, must be of drinking water quality in most cases – a quality that normally cannot be achieved by internal water treatment. Therefore, wastewater treatment in the food industry is primarily aimed at pre-cleaning the used water and preparing it for an introduction into the existing sewage system in line with the legal requirements.
Typical contaminations caused in the production of food are accumulations of organic substances in the water, such as vegetable or animal fats and oils. They usually get into the water when cleaning the production facilities. In order not to exceed the limit values for discharge into the sewerage, it is enough in many cases to remove free fats and oils by means of a grease separator.
However, this is not always possible. Due to high pressure and heat in the cleaning process (e.g. when a high-pressure cleaner is used) or the use of detergents (surfactants), fats and oils will emulsify. In this case, they cannot be separated easily from the water anymore and treatment by grease separator alone is not enough.
To ensure compliance with the limit values legally required, wastewater treatment can be complemented by installing an OKO-tech flotation system. First, the fat separator removes free fats. The downstream flotation system removes further contaminations, such as emulsified organic substances or cleaning agents from the wastewater and prepares it for an indirect discharge that is legally compliant.
When discharging wastewaters into the existing sewage system, the limit values for fats and oils (lipophilic substances) must be reliably observed. OKO-tech, a certified specialist according to the German WHG (Federal Water Act), offers qualified solutions, service and consulting. Due to their modularity, OKO-tech systems are flexible and space-saving. On request, OKO-tech also takes over the annual maintenance of your wastewater treatment system.
Hygiene regulations have the highest priority in the food industry. All food producing or food processing companies are bound by the Food Hygiene Regulation – every step of the production process is subject to strict safety and hygiene regulations.
The water used to produce food must be of drinking water quality. Reprocessing the water and reusing it in the production process, a common practice in other industries, is not possible due to the high-quality standards for the water. Therefore, large quantities of water are needed in the food industry – generally speaking, water consumption is thus one of the highest cost factors in this industry.
Wastewater treatment in the food industry means pre-treatment of the wastewater in most cases, in order to observe the limit values for legally compliant discharge into the existing sewage system.
The German Wastewater Ordinance (Abwasserverordnung – AbwV) provides quite different regulations for the various food production sectors, such as milk processing, oil-seed processing, production of fruit and vegetable products, production of soft drinks, fish processing or potato processing. The different directives show that the contaminations and pollutions differ from each other to a great extent.
In general, wastewaters from the food industry have a high concentration of organic matter. Whether large bakery, beverage industry, dairy, slaughterhouse or olive-oil production: a wastewater that contains organic matter in various concentrations is produced during food production or when cleaning machinery and equipment, depending on the type of plant. The concentration of organic matter in the wastewater is determined by the COD value. COD is the abbreviation for “Chemical Oxygen Demand” and refers to the amount of oxygen necessary for the degradation of organic contaminants. The COD value is given in mg/liter.
In order to determine the COD value, a wastewater sample is boiled in sulfuric acid solution to which oxidizing agents are added. The amount of consumed oxygen is calculated from the amount of oxidizing agents added. Nowadays, the determination is carried out easily and reliably by means of modern cuvette tests and a photometer.