We increased drinking water processing at the water pumping station by 300% with a supply interruption of only 6 hours.

Faced with significant variations in consumption during the summer days, the management of Miholjac’s water supply realized that they needed to significantly increase potable water production at the pumping station, which was operating with 40 liters per second capacity.

The bottleneck of the processing process was the deferization process, which cleaned arsenic, iron and manganese particles from the water. In addition, EU regulations have caught up with them, allowing the presence of arsenic micro-particles in processed drinking water to be much lower than their current norm.

It was concluded that the water treatment system must be improved, and its capacity should be increased so that in the future, it can withstand the increase in the number of connections to the system in the rural part of the water supply area.

Production was not allowed to stop.

The biggest challenge in implementing this project was the requirement that we build the drinking water processing plant within the existing plant, where the processing and distribution of drinking water must not stop.

Processed drinking water from the new plant must meet the strict standards of EU directives regarding the permitted amounts of microparticles (arsenic, manganese, iron) in distributed drinking water.

The implementation of this project also included the installation of new pumps for the distribution of drinking water.

The new pumps also needed a new control system. It was necessary to upgrade the pump control system with new frequency converters installed in the existing monitoring and control system distributors.

Then, they had to be connected to the existing monitoring and management system. The next step is the construction of a new, fourth well with which we planned to increase the capacity for raw water production. The investor also requested installing operator panels on the new ultrafiltration manifolds so that the entire plant could be managed through them in the event of an emergency or failure of the SCADA system.

The last request of the investor was an analysis of the electricity consumption of the entire plant to reduce the customer’s bills and compensate for part of the wasted energy.

How membrane ultrafiltration works

After creating a feasibility study, we proposed the introduction of a modern system that uses membrane ultrafiltration technology with a capacity of 45l/s. With this intervention, the total capacity of the water pumping station will increase to 85l/s.
During membrane ultrafiltration, iron, manganese and arsenic dissolved in water are oxidized with oxygen from the air (additionally, if necessary, with ozone, chlorine or iron-III-chloride). After oxidation, they are removed from the raw water on the surface of the micro/ultrafiltration membrane.

When large particles are filtered out, the water passes through active carbon filters, eliminating any organic matter present. 

The main advantage of this way of working is the modular design, which enables simple adaptation of production to current needs and easy eventual addition of new capacities (LEGO system) as well as regular replacement of existing membranes after the end of their useful life.

We are building a new well to increase the plant’s capacity by three times.

During the preparation of the feasibility study and calculation of all capacities, we realized that considering the course of development of the region and the potential increase in the need for drinking water in the broader area of ​​Miholjec, it is necessary to strengthen production capacities further.

Thus, in the project, we have foreseen the construction of an additional well for pumping raw water with a capacity of 40 l/s, which would raise the capacity of raw water production to 100 l/s

When the distribution pumps were subsequently reinforced and replaced, the network’s capacity increased to a maximum of 120l/s, three times more than the current production.

We are also implementing a new management system.

In addition to new pumps, an additional well, and a completely new filtration system, the supervisory control system had to be upgraded to include all the new parts of the system and harmonize them with the existing ones. During the implementation of the project, the existing SCADA (WinCC) was upgraded in parallel, which also controls the new part of the plant, the new well. The new system also brought numerous possibilities and variations when managing the plant.

The system was upgraded with three independent ultrafiltration modules with a capacity of 15l/s, totaling 45l/s. The production parameters of each module are managed completely independently.

We connected the new distributor of the ultrafiltration drive with the rest of the monitoring and control system using the PROFINET communication protocol, which is used to exchange the necessary information essential for the synchronous management of drinking water production from the entire plant. Siemens SIMATIC S7-300 hardware platform was used to automate the new part of the drive, which is identical to the existing monitoring and control system platform, to avoid possible incompatibilities and ensure stable and long-term operation of the system.

Consumers did not notice the interruption of supply.

The only stoppage in citizens’ regular drinking water supply occurred one night, lasting 6 hours. Unfortunately, it was not possible to reconnect the pipeline and replace the distribution pumps without draining the system. Still, in those 6 hours, not a single call from dissatisfied users was recorded – because everyone was asleep. To carry out such an upgrade of critical systems, which are very sensitive and regulate the entire production of drinking water without interruption (or with an almost imperceptible interruption) of the supply of citizens, without consequences for consumers, is an impressive undertaking, even for us.

The plant was put into operation on July 14, 2015. and has been working flawlessly ever since.