Monitoring and analyzing wastewater in the food industry: managing physico-chemical risks
Wastewater analysis in the food industry is essential for monitoring effluents, preventing physico-chemical drift and securing discharges. The diversity of production processes and the variability of flows require regular monitoring of key parameters, such as chemical oxygen demand and dissolved oxygen, to ensure reliable control of treatment systems.
In an increasingly demanding regulatory framework, discharge control relies on a structured measurement approach adapted to field constraints. This article presents the main challenges, control parameters, analytical methods and field feedback from industrial applications.
Characteristics and specific features of food industry effluents
Food industry wastewater mainly originates from processing operations, equipment cleaning, floor washing and process circuits. Its composition strongly depends on manufactured products, processed volumes and clean-in-place protocols.
These effluents may contain organic matter, fats, proteins, sugars and residues from cleaning products. Without appropriate analysis, it becomes difficult to anticipate impacts on treatment facilities or on the collection network. Wastewater analysis is therefore a key step in ensuring process stability and discharge compliance.
Effluent variability and impact on treatment
Pollution loads may fluctuate depending on production cycles, recipe changes or cleaning phases. Rapid variations can destabilize a treatment plant if not detected in time.
Insufficient analytical monitoring may result in operational malfunction, reduced treatment efficiency or regulatory threshold exceedances. Water analysis in the food industry makes it possible to identify these variations, adjust treatment conditions and improve operator responsiveness to process drift.
Which parameters should be monitored in the food industry?
Monitoring food industry wastewater relies on the analysis of physico-chemical parameters representative of pollutant load and treatment performance. These indicators allow facilities to be assessed and controlled, while verifying compliance before discharge.
Chemical oxygen demand
Chemical oxygen demand is a global indicator of the amount of oxidizable matter present in water. It reflects the organic and mineral load likely to consume oxygen during chemical reactions.
In the food industry, chemical oxygen demand is used to monitor the impact of manufacturing processes and cleaning operations. Regular monitoring helps verify treatment efficiency and rapidly detect pollution overload.
Continuous measurement provides reactive information, complementing periodic analyses performed in internal or external laboratories.
Dissolved oxygen in biological basins
Dissolved oxygen is a key parameter for controlling biological basins in industrial wastewater treatment plants. It directly affects the activity of microorganisms responsible for organic matter degradation.
Poorly controlled concentration levels may result in reduced treatment efficiency or excessive energy consumption. In food industry facilities, dissolved oxygen monitoring allows aeration to be adjusted according to incoming loads. This contributes to stabilizing biological treatment and optimizing overall plant performance.
Oxidation-reduction potential for biological reaction control
Oxidation-reduction potential provides complementary information on the state of biological reactions within basins. It helps assess oxidizing or reducing conditions, which are essential for monitoring nitrification and denitrification processes.
In certain food industry contexts, monitoring oxidation-reduction potential helps refine aerator control and improve nitrogen removal efficiency. This parameter is generally integrated into automated supervision and regulation systems.
Complementary physico-chemical indicators
Depending on activities and regulatory constraints, additional parameters may be monitored, such as pH, temperature, suspended solids or conductivity.
These measurements provide useful information about effluent stability and plant condition. Parameter selection depends on monitoring objectives, local requirements and site-specific characteristics. A tailored approach is necessary to ensure meaningful and operational wastewater analysis in the food industry.
Monitoring and analyzing wastewater in the food industry
Periodic analyses in an internal laboratory
Many food industry companies operate internal laboratories performing periodic analyses using micro-methods. These measurements allow certain parameters to be verified at regular intervals and help document discharge compliance.
However, this approach does not capture rapid effluent variations. Results depend on sampling frequency and may not reflect peak loads occurring between analyses.
Continuous on-site measurement
Continuous measurement allows real-time monitoring of key parameter evolution and immediate detection of process drift.
In the context of wastewater analysis in the food industry, in-line sensors provide operational data for treatment control. This approach improves team responsiveness and secures discharges before release.
Sensor data can be transmitted to plant supervision systems. This integration enables automated regulation, data archiving and performance analysis. Combining internal laboratory checks with continuous measurement provides complementary data sets.
Customer case: regional dairy processing site
A regional food industry company specializing in sheep’s milk dairy products operates its own wastewater treatment plant for process water treatment. The site must monitor several parameters to ensure plant performance and compliance before discharge to the municipal network.
Two parameters are continuously monitored: dissolved oxygen in the aeration basin and chemical oxygen demand at the plant outlet. The internal laboratory performs regular checks using micro-methods but does not provide continuous monitoring.
Adapting the measurement system to field constraints
After installing measurement equipment, the site encountered issues related to fatty organic matter present in the effluents. Deposits required frequent sensor cleaning, every five to six hours, to maintain reliable measurements.
This constraint limited monitoring continuity and required significant team involvement. An adaptation of the system was necessary to ensure long-term measurement reliability.
Aqualabo solutions
To strengthen self-monitoring, the site was equipped with an ACTEON 5000 transmitter combined with an OPTOD stainless steel oxygen sensor for the aeration basin, as well as an ACTEON 5000 transmitter with a STACSENSE ultraviolet sensor for chemical oxygen demand monitoring at the venturi channel outlet.
Automatic cleaning systems were subsequently added. These accessories were first tested through the rental service before validation.
This configuration significantly reduced manual intervention frequency. The oxygen sensor now requires only weekly cleaning, while cleaning operations for the STACSENSE sensor have been greatly reduced.
This improvement enhanced measurement continuity, monitoring reliability and site responsiveness to pollutant load variations.
Customer case: international dairy group
An international food industry group specializing in milk collection and processing has been collaborating with Aqualabo for several years for discharge self-monitoring. Several sites are equipped with samplers, measurement channels, flow meters and in-line analyzers.
On one major industrial site, effluents must be treated before discharge to the natural environment via an appropriate treatment plant. Precise aeration basin control requires continuous monitoring of dissolved oxygen and oxidation-reduction potential.
Equipment deployed on site
In this context, the equipment supplied includes:
- an ACTEON 5000 dual-channel transmitter
- an OPTOD sensor for dissolved oxygen and temperature monitoring
- an EHAN sensor for oxidation-reduction potential and temperature
Support poles facilitate sensor installation and maintenance within the medium.
Automated control and energy optimization
Measured concentrations are continuously transmitted to the plant programmable controller via standardized signals. This communication allows automatic aerator regulation according to thresholds defined in the supervision system.
This monitoring approach optimizes the removal of nitrogen, carbon and phosphorus loads while controlling energy consumption related to aeration. Archived data are used for diagnostics and post-treatment analysis.
Aqualabo, partner of food industry
For production managers, environmental technicians and treatment plant operators, wastewater analysis in the food industry makes it possible to better understand effluent behavior, anticipate physico-chemical drift and intervene proactively before non-compliance, plant malfunction or regulatory exceedance occurs.
Aqualabo supports food industry companies with analytical solutions adapted to industrial constraints and field requirements. To define the most suitable measurement methods and equipment for your wastewater treatment configuration, Aqualabo teams are available to assist you.
