In the recycling of plastic from household waste, water plays an essential role in the production process. Washing stages remove residues, impurities and contaminants from plastic materials, preparing them for subsequent processing and turning them into a raw material that can be used again. Since water is an integral part of the production cycle, accurately measuring its consumption is essential for promptly identifying anomalies and taking action before they result in unnecessary water use or plant downtime. This was the requirement behind a project carried out at a plant dedicated to recycling plastic waste from household collection, where ISOIL Industria’s ISOMAG instrumentation provides reliable measurement of water consumption across the different production lines.
The role of water in the plastic recycling process
In mechanical plastic recycling, water is used in several consecutive stages of the process.
After grinding, which reduces the material to flakes, the material typically passes through several washing stages. The first is friction washing, during which the flakes are cleaned by rubbing against each other and against the paddles inside the washing equipment. Detergents are often added to remove oily residues and surface contaminants. This is followed by one or more rinsing stages to remove detergent residues.
Another important stage is flotation, in which the flakes are immersed in water tanks. Differences in polymer density allow the materials to be physically separated according to their ability to float. This is one of the most critical stages of the entire process, as the purity of the material leaving the plant largely depends on the effectiveness of this separation.
The fact that the process involves multiple stages, often distributed across several parallel lines, makes a single aggregated measurement of water consumption insufficient. A change in flow rate at a specific stage or on an individual line can have very different causes. Only measurement data collected at individual points throughout the process makes it possible to distinguish between them and quickly identify the source of a problem.
Measurement also plays an important role in a second area: the treatment and reuse of washing water. Wastewater generated during these stages is often treated through coagulation, flocculation and sludge separation processes. In some plants, dissolved air flotation (DAF) systems are also used. The aim is to enable the treated water to be returned to the production cycle rather than discharged.
Here too, knowing exactly how much water is being drawn and which production line is using it is the first step in assessing how much water could potentially be recovered. Over time, this data can also be used to build a realistic plant water balance based on actual measurements rather than estimates.
It was in this type of environment — with multiple production lines, several process stages and measurement points distributed throughout the plant — that the project described below was implemented.
The context
The plant comprised three washing lines and two lines dedicated to bulk water supply, with measurement requirements distributed across several points in the process.
The objective was twofold: to accurately determine the water consumption of each line and, at the same time, to promptly identify any deviations from normal operating conditions.
The Challenge
The customer required a flow measurement technology capable of providing reliable flow rate data, while also being easy to integrate into an existing, fully operational plant.
There was also an important installation constraint: the existing pipelines were made of PVC, so the measurement technology needed to be installed without requiring complex modifications to the existing infrastructure.
The ISOMAG flow meters made it possible to combine measurement accuracy and long-term reliability with ease of installation and operation, while keeping costs compatible with an application involving multiple measurement points.
The Solution: ISOMAG MS2500 Flow Meters and MV800 Converters
To meet these requirements, 48 ISOMAG MS2500 electromagnetic flow meters were installed at the critical points identified throughout the plant, together with ISOMAG MV800 ultra-compact converters.
The solution enables continuous acquisition of water consumption data, giving operators an immediate and continuous overview of the operating conditions of each production line.
A particularly valuable feature was the possibility of installing the instrumentation directly on the existing PVC pipelines without the use of grounding rings. This significantly simplified the installation process, allowing the flow meters to be integrated into the plant without invasive modifications or extended periods of downtime.
The Benefits
The installation of the flow meters introduced a water consumption monitoring system based on reliable, real-time data. Knowing exactly how much water is being used by each production line at any given time makes it possible to move from a management approach based on estimates or overall consumption figures to one based on precise, verifiable data.
The main benefits of the solution include:
- accurate and reliable measurement of water flow rate;
- real-time monitoring of water consumption on each production line;
- improved ability to identify abnormal water usage;
- simplified installation on PVC pipelines, without grounding rings;
- easy-to-use technology with a cost-effective solution;
- local technical assistance and support.
For further information about ISOIL Industria’s range of ISOMAG electromagnetic flow meters or for a free consultation, please contact our specialists.
FAQ about ISOMAG Flow Meters in a Plastic Recycling Plant
Why is water so important in plastic recycling?
Washing, rinsing and flotation stages use water to remove impurities and contaminants from plastic flakes and to separate different polymers according to their density. These stages are essential to achieving the level of purity required for the recycled material to be used again in the production cycle.
Can a flow meter be installed on PVC pipelines without modifying the plant?
Yes. Certain flow measurement technologies can be installed directly on existing pipelines, including PVC pipelines, without the use of grounding rings and without invasive modifications to the infrastructure. This is particularly important for plants that are already in operation, where extended downtime or structural modifications can result in significant costs and operational disruption.
What is the purpose of real-time water consumption monitoring?
Real-time monitoring makes it possible to move from a management approach based on estimates or overall consumption figures to one based on precise, verifiable data. This allows abnormal water usage to be identified promptly and corrective action to be taken before it leads to unnecessary water consumption or plant downtime.
What are the key strengths of ISOIL Industria’s MS2500 flow meters?
The main strength of the MS2500 is its high degree of adaptability. A single sensor covers a wide range of diameters, flow rates, pressures and temperatures and can be configured with different materials and converters. This makes it particularly suitable when a versatile, configurable flanged electromagnetic flow meter for industrial and water applications is required.
What are the benefits of the MS2500 + MV800 combination?
The value of this solution lies in the complementarity of the two components. The MS2500 provides an extremely versatile sensor, available in numerous diameters and configurations, while the MV800 adds a compact, protected converter that is particularly well suited to field installations.
