From Compliance to Excellence: Transforming Wastewater Management in Serbia

Within the EU urban wastewater is one of the main sources of water pollution. Over the last 30 years, legislation has been in place that aims to improve this situation and, due to stringent regulations surrounding the treatment of wastewater, water quality within the EU has improved significantly, directly impacting the quality of lakes, rivers, seas and groundwater and the health of the surrounding communities. According to the European Council, compliance with regulation is almost 100% with over 90% of water now being collected and successfully treated.

Previously these regulations applied only to large towns, however, recent revisions have ensured that all towns with a population exceeding 1000 will need to comply with the laws pertaining to the treatment of wastewater by 2035. This most notably requires setting up wastewater collecting systems and treating it to remove biodegradable organic matter, before discharging it back into the environment (Wastewater treatment - Consilium (europa.eu)).

Currently, Serbia is not part of the EU, however, the country has submitted an application for membership and, as part of the application process will need to bring its wastewater and environmental protections in line with EU standards.

Meeting the Challenge

Prior to joining the EU, Serbia must be able to process over 90% of its wastewater, Government statistics state that this figure currently sits at less than 20%. Serbia has until 2040 to build treatment plants for towns and cities. (Reuters, 2024).

This modern WWTP is an activated sludge plant, turning leftover sludge into biogas to create heat and power. Managing the wastewater from an area populated by 90,000 inhabitants required a solution for the monitoring of wastewater influent to provide smooth, efficient operation and ensure that any water discharged from the plant into the Morava River had been properly treated to the required standards, protecting the health of the surrounding communities and local environment and representing a huge step in the right direction for compliance with legislation, paving the way for EU accession.

Prior to the installation, wastewater influent was measured at regular intervals through manual, intermittent laboratory tests at the entrance to the plant. However, this method was proving to be unsuccessful and frequently incidents were happening in between the allocated testing times at enormous financial and ecological cost. With the vast majority of events and violations happening extremely quickly and within a short time span, it was all too easy for them to go undetected. Operators were increasingly finding that their current systems were unreliable and ineffective, as they provided no real way to predict events and prevent inevitable damage ahead of time. This new system brings together the BlueEdge™ by Badger Meter elements of Measurement and Control, Connectivity and Communication and Insight and Action to provide continuous monitoring of vital parameters and generate accurate and actionable data in real-time. The system highlights any changes in the condition of the wastewater as they are happening and alerts operators so that preventive action to avoid incidents and prevent large-scale damage can be taken immediately.

The Solution

With an initial objective of improved water quality and flow monitoring at the plant, the basis of the proposal was formed around the continuous online measurement of chemical oxygen demand (COD), total suspended solids (TSS), acidity (pH), conductivity and temperature. These vital parameters would be measured alongside flow level and velocity.

A Raven Eye 2 Non-Contact Radar Flow Meter was installed to provide continuous measurements of flow level and velocity. Water quality sensors were also installed to monitor the critical parameters of COD, TSS, conductivity, pH and temperature with the Badger Meter i::scan, pH::lyser and condu::lyser being recommended for the project. The sensors all communicate with a con::cube which transmits data back to the plant's SCADA / EMS system.

The measurement of these analytical parameters alongside those of flow, velocity and level provided valuable, actionable data, enabling improved management of the wastewater treatment plant while providing enhanced protection against incidents such as extreme chemical and biological pollution and the build-up of sludge and sand deposits.

After preliminary discussions with the end user, it was recognized that the plant would also benefit from an expanded system that integrated the data processing of other existing networks such as the aeration systems and pump stations. These additional functionalities, alongside the flow and water quality measurement system, allowed for the creation of an enhanced energy management system that enabled substantial savings on operational costs to be achieved.

The Installation

This challenging, turnkey installation comprises three main parts, the automatic analyzing station, the main collector flow measurement system and the SCADA/EMS system.

The automatic analyzing station was built and installed at a distance of 2000m from the plant, which provides adequate time to respond to incidents and avoid pollution events. Incorporating both the system for monitoring water quality and an industrial computer featuring a con::cube, a versatile terminal for data acquisition and control, the station is equipped with IoT (Internet of Things) functionality. The con::cube is IP65 rated, low powered, (consuming 3W at a measurement interval of 15 minutes) and offers simple touch screen operation. It is capable of spectral analysis and can control stations and sensors of up to 64 parameters. With additional functions including automatic cleaning, remote calibration, sensor function check, and enhanced data recording and simple transfer, it is able to record and analyze the information obtained from the sensors.

The station is responsible for the automatic operation of the water quality sensors, mechanical and compressed air probe cleaning systems and sampling systems. It also integrates signals from the non-contact flow measurement system, located on the main flow collector pipe, and communicates remotely via the con::cube with the SCADA/EMS system that is housed in the main operator center on the treatment plant, allowing the system to perform preventive actions and protect the vital functions of the system, ensuring plant optimization and longevity.

The automatic analyzing station also houses the water quality monitoring sensors and Badger Meter was happy to be able to deliver a cutting-edge solution with the installation of the i::scan, condu::lyser and pH::lyser instrumentation. This plug-and-measure technology simplifies installation and, with no consumables or moving parts, offers minimal maintenance. The i::scan provided the extra benefits of low-power operation, advanced light emission technology and spectral processing to obtain results. Mounted within flow cells, these sensors have been adapted for automatic air cleaning, simplifying their operation and maintenance and further guaranteeing reliability, stability and accuracy and the ability to provide continuous visibility of the wastewater quality on the plant.

The Raven Eye 2 Non-Contact Radar Flow Meter forms a vital component of the main collector pipe flow measurement system. Installed above the water level, this monitor is able to measure both flow velocity and level to determine the flow rates within the plant. Ideal for flow monitoring on wastewater plants, this intelligent solution offers simple, single-entry installation while the completely sealed IP68 design and the self-calibrating feature eliminate the need for ongoing field maintenance and calibration. Continuous monitoring is carried out using Doppler technology, meaning that the sensors do not have to be submerged, further lessening the need for ongoing maintenance as the threat of sensor fouling and sediment buildup is removed. Data is taken from the monitor and transmitted back to the con::cube within the automatic analyzing station, the enhanced data logging ensures that plant operators have a clear view of wastewater flow and allows for improved plant functionality.

Conclusion

Since its installation in July 2021, the system has demonstrated that it can efficiently operate without interruption in extremely challenging conditions, continuously measuring and analyzing key parameters of completely unprepared wastewater. The continuous and accurate data streams have allowed for superior plant management alongside enhanced energy efficiency while the ability to detect events ahead of time and perform preventative action has been vital to the operation of the plant.

With 65 pollution events being avoided within the first six months of installation, it is evident that this installation is hugely important to the future success of the wastewater treatment plant. The implementation of this BlueEdge™ solution by Badger Meter has set new standards for wastewater quality and quantity monitoring. The success of this project may influence many others in the region, increasing the standards of health for local communities, protecting the flora and fauna of the native environment and improving the water quality of the Morava River for future generations.