Hana Posavcic

• Doctor of Engineering
• Assistant at Faculty of Civil Engineering University of Zagreb

Featured Application Electrochemical treatment of water and wastewater, primarily those contaminated with selenium and/or strontium. Abstract This study investigated the removal of selenium (Se) and strontium (Sr) from water using a three-stage electrochemical reactor with integrated pH control. A total of 102 experiments were performed following...

The growing amounts of sewage sludge (SS) and water pollution caused by heavy metals are major environmental concerns. This study addresses both issues by investigating the potential of biochar derived from SS gasification at an experimental plant as an effective adsorbent for the removal of selected heavy metals, cadmium, chromium, copper, and lea...

Chemical kinetics can be a useful tool for determining the optimal operating time of electrochemical processes. The main objective of the study was to determine the mineral oil removal rate by sono-electrochemical treatment. In this study, zero-, first-, and second-order kinetic models were used to determine the reaction rate of mineral oil removal...

Ultrasonic technology can be used in various branches of industry, but its use in water and wastewater treatment has not yet been sufficiently researched. The aim of this paper is to investigate the application of ultrasound in wastewater treatment, with a focus on oily wastewater. In the experimental study, ultrasound was combined with electrocoag...

Chemical kinetics can be a useful tool for determining the optimal operating time of electrochemical processes. A review of the state of knowledge revealed that the rate of chemical reactions in the treatment of oily wastewater by sono-electrochemical treatment has not yet been investigated. Therefore, the main objective of the study was to determi...

Intencija je EU da se analize utjecaja projekata na klimatske promjene sustavno uključe u širok raspon privatnih i javnih projekata, pa tako i u slučaju vodnokomunalnih projekata i izgradnje uređaja za pročišćavanje otpadnih voda (UPOV). Glavni staklenički plinovi koji se oslobađaju u atmosferu u postupcima pročišćavanja otpadnih voda su metan, ugl...

Poznato je da industrijske otpadne vode značajno utječu na cjelokupan okoliš. Iako su danas u primjeni razne tehnologije uklanjanja ulja iz vode, rijetko kojom tehnologijom je moguće ispuniti uvjete propisane zakonskom regulativom, uz istovremeno osiguranje brzog i ekonomski isplativog postupka. Među već poznatim tehnologijama, svoje mjesto su našl...

Choosing the right method for floc separation after electrochemical treatment seemed to be a problem in a number of previous research papers. Therefore, ultrasonic and electrochemical (sono-EC) processes in circulating flow mode were combined with settling and filtration to treat the oily wastewater and to remove the produced flocs. Experimental re...

3D numerical simulations and measurements on an electrochemical reactor were used to analyze the efficiency of strontium removal from water, with and without simultaneous ultrasound treatment. Ultrasound was generated using 4 ultrasonic transducers with an operating frequency of 25 kHz. The reactor used 8 aluminum electrodes arranged in two blocks....

Since high concentrations of selenium and strontium in water can potentially harm human health, various methods have been developed for their treatment. The objective of this paper was to validate previously published studies on the electrochemical removal of selenium and strontium, while also reducing the reactor operating time and using an ultras...

This paper examines the removal of mineral oil from oily wastewater by a hybrid ultrasonic and electrochemical circulating flow process. The Box-Behnken design was used to study the effects of number of cycles, current density, flow rate and the presence of ultrasound on the efficiency of mineral oil removal and process optimization. A reduced cubi...

Wastewater containing oil is becoming a growing problem worldwide due to increasing quantities and existing pollution. The pollutants contained in these effluents, when released into the environment, affect surface and groundwater pollution, endanger human life and health, and pollute the atmosphere. Their sustainable treatment should be cost-effec...

Energy efficiency of the water pipeline system is analysed on the physical model of the water supply system through the application of the pump with nominal characteristics (unregulated pump) and the same pump controlled by variable frequency drive (frequency regulation). The functional advantage of pump frequency regulation is quantified in terms...

Abstract In this paper, ultrasonic treatment, electrocoagulation and the combinations of these treatments were compared for the removal of manganese, nickel, cobalt, cadmium and chromium from a synthetic solution. Experiments were conducted using aluminium electrodes in a modified ultrasonic bath. The experimental design approach (DOE) and multi-le...

In this study, the influence of the electrode material and the initial concentration of heavy metals on the efficiency of their removal from water by the electrocoagulation process is investigated. The experiments were carried out in a batch reactor with aluminium, iron, copper and graphite electrodes at three different contaminant concentrations....

The increasing production of oily wastewater as a by-product of industry has become a major environmental problem. Therefore, this article investigates the removal of mineral oil from oily wastewater by a circulating flow sono-electrocoagulation. The Box-Behnken design was used to study the effects of characteristic electrocoagulation and ultrasoni...

Local water supply systems pose the greatest risk from a public health perspective because water is delivered to consumers without any treatment and often even without disinfection. The most common causes of contamination are microbiological contamination and elevated concentrations of heavy metals. Such water must be treated to be safe for human c...

Jedan od problema vezanih za pitku vodu jest i onečišćenje teškim metalima. Uslijed svoje toksične, biološki nerazgradive i postojane prirode, predstavljaju ozbiljan rizik za vodene ekosustave, ali i zdravlje čovjeka. U svrhu njihovog uklanjanja iz voda, moguće je koristiti niz različitih metoda čiji je pregled dan u ovom radu. Konvencionalni p...

In this paper the effect of ultrasound and electrocoagulation on the removal of manganese from synthetic wastewater was investigated. It was shown that 20 kHz ultrasound alone is not very efficient for manganese removal, but it enhances the efficiency of electrocoagulation. It was also shown that settling has a great effect on the electrocoagulatio...

Oily wastewater is becoming a concern worldwide due to its quantities and the presence of contaminants and its sustainable treatment should be cost-effective and meet all requirements so the contaminants are not transferred to the environment. The paper reviews the state-of-the-art in the oily wastewater treatment by electrochemical processes such...

Potable water is water of acceptable quality in terms of physical, chemical, and microbiological parameters for safe drinking. Although it is a basic human need and right, ensuring access to drinking water has been and continues to be a challenge. Waterborne diseases are still an issue in many developing countries and deaths from diseases such as c...

Water conditioning is a method of removing altering minerals, chemicals and contaminants from a water source and it is carried out on facilities equipped with the corresponding electro-mechanical equipment. Although efficient, conventional processes typically use several complex devices connected to a single functional unit, which are often expensi...

The average water pressure in a water supply system is usually determined as the weighted (by some parameter) average value of all pressures. In IWA (International Water Association) methodology, average pressure is used for calculating 'Unavoidable Annual Real Losses' (UARL), which are a core component for deriving the ILI index (Infrastructure Le...