Based on previous drinking water analyses, we proposed the construction of a new water treatment plant with pressure sand filters with a capacity of 13.5 m3/h, which have proved most appropriate for the treatment of less polluted surface water. Water filtration was improved by dosing coagulation agent at the point of raw water entry before filters with a Grundfos DDC dosing pump.
For conducting turbidity measurements at the entry into and exit from the purification plant, a turbidity sensor Turbimax by Endress+Hauser was installed at the entry into and exit from the purification plant. Furthermore, an ABB WaterMaster flow meter was installed at the point of raw water entry and before the point where conditioned water is released into the Podslivnica water mains and the Mahneti water storage facility, and a buried ABB AquaMaster 3 electromagnetic flow meter was installed in the Podslivnica-Brezje gravity-flow pipeline for water consumption monitoring and dosing of coagulation agent and disinfectant into the water supply system.
Before distributing drinking water to consumers, the water must be disinfected, which has been achieved by installing a compact system for the production of chlorine dioxide (Oxiperm Pro by Grundfos). Oxiperm Pro produces chlorine dioxide at the point of installation by using diluted solutions of sodium chlorite (NaClO2, 7,5 %) and hydrochloric acid (HCl, 9 %), and has been recognised as the safest solution for disinfecting water by adding chlorine.
Clean and microbiologically safe water is accumulated in two polyester reservoirs with a capacity of 20 m3, which provide the necessary quantity of water for backwashing of filters and to cover the demand of consumers.
All pipeline connections in the facility were carried out with a system of stainless steel quick-connect fittings supplied by Victaulic to avoid time-consuming installation, welding and x-ray control of weld joints.
Electric installations, control of technological equipment and integration into the central control system of JP Komunala Cerknica (public water utility ) have also been provided for the entire purification plant. The complete solution and installation were completed in April 2019.