Modelling of a specific groundwater vulnerability in the karst conditions of the Dugopolje area : doctoral thesis

Tijekom proteklih pedeset godina javnost je prepoznala potrebu za očuvanjem kakoće i količine podzemne vode kao bitnog izvora pitke vode u Hrvatskoj i svijetu. Zbog svojih specifičnosti, kao što su tanak pokrov, koncentrirana infiltracija, ponori te koncentriranje toka u epikrškoj i vadoznoj zoni, krški vodonosnici su poznati po svojoj osjetljivosti na onečišćenje. Zbog svoje reaktivnosti, tlo i sediment predstavljaju značajan čimbenik u zadržavanju i usporavanju potencijalnog onečišćenja na njegovom putu prema podzemnoj vodi. Za područje istraživanja odabran je širi prostor krškog polja Dugopolja. Polje je smješteno sa sjeverne strane planine Mosor, a pruža se pravcem sjeverozapad-jugoistok i blago je nagnuto prema jugoistoku. Nova gospodarska zona i razvoj cestovne infrastrukture su do tada pretežito ruralni krajolik pretvorili u jedan od najpropulzivnijih krajeva u Hrvatskoj, a broj ljudi koji su ondje pronašli radno mjesto nadmašio je broj stalnih stanovnika tog područja. Zajedno s ekonomskim napretkom, na ovo područje došla je i opasnost od onečišćenja tla i podzemnih voda te je primjećen trend pogoršanja kakvoće vode izvora Jadra i Žrnovnice. U ovom radu prirodna ranjivost procijenjena je pomoću metode COP u svrhu određivanja najranjivijih područja kojima je potreba posebna zaštita. Na temelju karte prirodne ranjivosti izrađena je karta specifične ranjivosti koja uzima u obzir fizikalna i geokemijska svojstva tla, nezasićene i zasićene zone i procese vezane uz njih, svojstva pojedine vrste onečišćivala i njihovo ponašanje u određenim geokemijskim uvjetima koji vladaju u različitim dijelovima krškog vodonosnika. Na temelju rezultata analiza i mjerenja fizikalnih, fizikalno-kemijskih i kemijskih parametara tla krškog polja i ispune epikrške zone, ocijenjeno je ponašanje pojedinih vrsta onečišćenja u pokrovu krških vodonosnika. Izvršena je prilagodba težinskih faktora koji se koriste u modeliranju specifične ranjivosti podzemnih voda geokemijskim uvjetima koji vladaju u različitim dijelovima hidrogeološkog sustava krškog podzemlja prekrivenog crvenicom. Dobiveni rezultati dali su značajan doprinos poznavanju mogućnosti prihvatnog kapaciteta tla i epikrške zone zaštiti krških vodonosnika, ne samo Dinarida, već i prostora sličnih litoloških, odnosno hidrogeoloških obilježja.Over the past fifty years, the public has recognized the need to protect quality and quantity of groundwater from karst aquifers as a source of potable water in Croatia and the world. Due to their specific characteristics, such as a thin soil cover, concentrated infiltration, swallow holes and concentration of flow in the epikarst and vadose zones, karst aquifers are known for their sensitivity to pollution. Contaminants can be transported very fast or even stored depending on the existence of fast or slow flow components in a karst system. Due to its reactivity, soil and sediment represent a significant factor in retardation and attenuation of potential pollution on its way to groundwater. Dugopolje is a typical karst field located on the northern slopes of the Mosor mountain facing northwest-southeast and sloping slightly toward the southeast. The area consists largely of mesozoic and kenozoic carbonate and clastic rocks. Because of the intensive tectonics, area is intensively karstified with couple of active swallow holes. The soils comprise brown and red soils on limestones and dolomites. The new economic zone and the development of road infrastructure (mainly Adriatic highway) have so far transformed the rural landscape into one of the most propulsive areas in Croatia, and the number of people who have found work there exceeded the number of permanent residents of the area. Along with the economic progress, came the danger of soil and groundwater contamination that is noticeable in deterioration of water quality of Jadro and Žrnovnica springs. The intrinsic vulnerability takes into account the geological, hydrological and hydrogeological properties of the area, regardless of the contaminant properties and the means of contamination, whereas specific vulnerability takes into account the properties of each individual contaminant. In this paper, the intrinsic vulnerability was assesed using the COP method to determine the most vulnerable areas that need special protection. Based on the map of the intrinsic vulnerability, a map of specific vulnerability has been developed. It takes into account the physical and geochemical properties of the soil, the unsaturated and saturated zones and processes associated with them, the properties of a particular type of contaminant and their behavior under certain geochemical conditions in different parts of the karst aquifers. The behavior of certain types of contamination in the karst aquifers was evaluated based on the results of the analysis and measurement of physical, physiochemical and chemical parameters of karst soil and filling of the epikarst zone. Adjustment of weights factors used in modeling the specific vulnerability of groundwater was performed according to geochemical conditions in various parts of the karstic hydrogeological system covered in red soil. The results of geochemical modeling using PHREEQC directly indicate the ionic form or the method of transport of chosen contaminant species. Arsenic and lead are predominantly related to the suspended soil and sediment particles and nitrates are migrable in the form of ions. Therefore, the mentioned contaminants can be transported over long distances without significant change. The obtained results have contributed significantly to the understanding of the soil and the epikarst zone storage capacity, not only in the Dinarides, but also in the areas with similar lithological and hydrogeological features. Steps have been taken in the last ten years to ensure improvements in quality of the spring waters of Jadra and Žrnovnica. A series of collectors and laggons were constructed along the Adriatic highway along with the closed water drainage system and sewage network in the Dugopolje area

Modelling of a specific groundwater vulnerability in the karst conditions of the Dugopolje area : doctoral thesis

Tijekom proteklih pedeset godina javnost je prepoznala potrebu za očuvanjem kakoće i količine podzemne vode kao bitnog izvora pitke vode u Hrvatskoj i svijetu. Zbog svojih specifičnosti, kao što su tanak pokrov, koncentrirana infiltracija, ponori te koncentriranje toka u epikrškoj i vadoznoj zoni, krški vodonosnici su poznati po svojoj osjetljivosti na onečišćenje. Zbog svoje reaktivnosti, tlo i sediment predstavljaju značajan čimbenik u zadržavanju i usporavanju potencijalnog onečišćenja na njegovom putu prema podzemnoj vodi. Za područje istraživanja odabran je širi prostor krškog polja Dugopolja. Polje je smješteno sa sjeverne strane planine Mosor, a pruža se pravcem sjeverozapad-jugoistok i blago je nagnuto prema jugoistoku. Nova gospodarska zona i razvoj cestovne infrastrukture su do tada pretežito ruralni krajolik pretvorili u jedan od najpropulzivnijih krajeva u Hrvatskoj, a broj ljudi koji su ondje pronašli radno mjesto nadmašio je broj stalnih stanovnika tog područja. Zajedno s ekonomskim napretkom, na ovo područje došla je i opasnost od onečišćenja tla i podzemnih voda te je primjećen trend pogoršanja kakvoće vode izvora Jadra i Žrnovnice. U ovom radu prirodna ranjivost procijenjena je pomoću metode COP u svrhu određivanja najranjivijih područja kojima je potreba posebna zaštita. Na temelju karte prirodne ranjivosti izrađena je karta specifične ranjivosti koja uzima u obzir fizikalna i geokemijska svojstva tla, nezasićene i zasićene zone i procese vezane uz njih, svojstva pojedine vrste onečišćivala i njihovo ponašanje u određenim geokemijskim uvjetima koji vladaju u različitim dijelovima krškog vodonosnika. Na temelju rezultata analiza i mjerenja fizikalnih, fizikalno-kemijskih i kemijskih parametara tla krškog polja i ispune epikrške zone, ocijenjeno je ponašanje pojedinih vrsta onečišćenja u pokrovu krških vodonosnika. Izvršena je prilagodba težinskih faktora koji se koriste u modeliranju specifične ranjivosti podzemnih voda geokemijskim uvjetima koji vladaju u različitim dijelovima hidrogeološkog sustava krškog podzemlja prekrivenog crvenicom. Dobiveni rezultati dali su značajan doprinos poznavanju mogućnosti prihvatnog kapaciteta tla i epikrške zone zaštiti krških vodonosnika, ne samo Dinarida, već i prostora sličnih litoloških, odnosno hidrogeoloških obilježja.Over the past fifty years, the public has recognized the need to protect quality and quantity of groundwater from karst aquifers as a source of potable water in Croatia and the world. Due to their specific characteristics, such as a thin soil cover, concentrated infiltration, swallow holes and concentration of flow in the epikarst and vadose zones, karst aquifers are known for their sensitivity to pollution. Contaminants can be transported very fast or even stored depending on the existence of fast or slow flow components in a karst system. Due to its reactivity, soil and sediment represent a significant factor in retardation and attenuation of potential pollution on its way to groundwater. Dugopolje is a typical karst field located on the northern slopes of the Mosor mountain facing northwest-southeast and sloping slightly toward the southeast. The area consists largely of mesozoic and kenozoic carbonate and clastic rocks. Because of the intensive tectonics, area is intensively karstified with couple of active swallow holes. The soils comprise brown and red soils on limestones and dolomites. The new economic zone and the development of road infrastructure (mainly Adriatic highway) have so far transformed the rural landscape into one of the most propulsive areas in Croatia, and the number of people who have found work there exceeded the number of permanent residents of the area. Along with the economic progress, came the danger of soil and groundwater contamination that is noticeable in deterioration of water quality of Jadro and Žrnovnica springs. The intrinsic vulnerability takes into account the geological, hydrological and hydrogeological properties of the area, regardless of the contaminant properties and the means of contamination, whereas specific vulnerability takes into account the properties of each individual contaminant. In this paper, the intrinsic vulnerability was assesed using the COP method to determine the most vulnerable areas that need special protection. Based on the map of the intrinsic vulnerability, a map of specific vulnerability has been developed. It takes into account the physical and geochemical properties of the soil, the unsaturated and saturated zones and processes associated with them, the properties of a particular type of contaminant and their behavior under certain geochemical conditions in different parts of the karst aquifers. The behavior of certain types of contamination in the karst aquifers was evaluated based on the results of the analysis and measurement of physical, physiochemical and chemical parameters of karst soil and filling of the epikarst zone. Adjustment of weights factors used in modeling the specific vulnerability of groundwater was performed according to geochemical conditions in various parts of the karstic hydrogeological system covered in red soil. The results of geochemical modeling using PHREEQC directly indicate the ionic form or the method of transport of chosen contaminant species. Arsenic and lead are predominantly related to the suspended soil and sediment particles and nitrates are migrable in the form of ions. Therefore, the mentioned contaminants can be transported over long distances without significant change. The obtained results have contributed significantly to the understanding of the soil and the epikarst zone storage capacity, not only in the Dinarides, but also in the areas with similar lithological and hydrogeological features. Steps have been taken in the last ten years to ensure improvements in quality of the spring waters of Jadra and Žrnovnica. A series of collectors and laggons were constructed along the Adriatic highway along with the closed water drainage system and sewage network in the Dugopolje area

Modelling of a specific groundwater vulnerability in the karst conditions of the Dugopolje area : doctoral thesis

Tijekom proteklih pedeset godina javnost je prepoznala potrebu za očuvanjem kakoće i količine podzemne vode kao bitnog izvora pitke vode u Hrvatskoj i svijetu. Zbog svojih specifičnosti, kao što su tanak pokrov, koncentrirana infiltracija, ponori te koncentriranje toka u epikrškoj i vadoznoj zoni, krški vodonosnici su poznati po svojoj osjetljivosti na onečišćenje. Zbog svoje reaktivnosti, tlo i sediment predstavljaju značajan čimbenik u zadržavanju i usporavanju potencijalnog onečišćenja na njegovom putu prema podzemnoj vodi. Za područje istraživanja odabran je širi prostor krškog polja Dugopolja. Polje je smješteno sa sjeverne strane planine Mosor, a pruža se pravcem sjeverozapad-jugoistok i blago je nagnuto prema jugoistoku. Nova gospodarska zona i razvoj cestovne infrastrukture su do tada pretežito ruralni krajolik pretvorili u jedan od najpropulzivnijih krajeva u Hrvatskoj, a broj ljudi koji su ondje pronašli radno mjesto nadmašio je broj stalnih stanovnika tog područja. Zajedno s ekonomskim napretkom, na ovo područje došla je i opasnost od onečišćenja tla i podzemnih voda te je primjećen trend pogoršanja kakvoće vode izvora Jadra i Žrnovnice. U ovom radu prirodna ranjivost procijenjena je pomoću metode COP u svrhu određivanja najranjivijih područja kojima je potreba posebna zaštita. Na temelju karte prirodne ranjivosti izrađena je karta specifične ranjivosti koja uzima u obzir fizikalna i geokemijska svojstva tla, nezasićene i zasićene zone i procese vezane uz njih, svojstva pojedine vrste onečišćivala i njihovo ponašanje u određenim geokemijskim uvjetima koji vladaju u različitim dijelovima krškog vodonosnika. Na temelju rezultata analiza i mjerenja fizikalnih, fizikalno-kemijskih i kemijskih parametara tla krškog polja i ispune epikrške zone, ocijenjeno je ponašanje pojedinih vrsta onečišćenja u pokrovu krških vodonosnika. Izvršena je prilagodba težinskih faktora koji se koriste u modeliranju specifične ranjivosti podzemnih voda geokemijskim uvjetima koji vladaju u različitim dijelovima hidrogeološkog sustava krškog podzemlja prekrivenog crvenicom. Dobiveni rezultati dali su značajan doprinos poznavanju mogućnosti prihvatnog kapaciteta tla i epikrške zone zaštiti krških vodonosnika, ne samo Dinarida, već i prostora sličnih litoloških, odnosno hidrogeoloških obilježja.Over the past fifty years, the public has recognized the need to protect quality and quantity of groundwater from karst aquifers as a source of potable water in Croatia and the world. Due to their specific characteristics, such as a thin soil cover, concentrated infiltration, swallow holes and concentration of flow in the epikarst and vadose zones, karst aquifers are known for their sensitivity to pollution. Contaminants can be transported very fast or even stored depending on the existence of fast or slow flow components in a karst system. Due to its reactivity, soil and sediment represent a significant factor in retardation and attenuation of potential pollution on its way to groundwater. Dugopolje is a typical karst field located on the northern slopes of the Mosor mountain facing northwest-southeast and sloping slightly toward the southeast. The area consists largely of mesozoic and kenozoic carbonate and clastic rocks. Because of the intensive tectonics, area is intensively karstified with couple of active swallow holes. The soils comprise brown and red soils on limestones and dolomites. The new economic zone and the development of road infrastructure (mainly Adriatic highway) have so far transformed the rural landscape into one of the most propulsive areas in Croatia, and the number of people who have found work there exceeded the number of permanent residents of the area. Along with the economic progress, came the danger of soil and groundwater contamination that is noticeable in deterioration of water quality of Jadro and Žrnovnica springs. The intrinsic vulnerability takes into account the geological, hydrological and hydrogeological properties of the area, regardless of the contaminant properties and the means of contamination, whereas specific vulnerability takes into account the properties of each individual contaminant. In this paper, the intrinsic vulnerability was assesed using the COP method to determine the most vulnerable areas that need special protection. Based on the map of the intrinsic vulnerability, a map of specific vulnerability has been developed. It takes into account the physical and geochemical properties of the soil, the unsaturated and saturated zones and processes associated with them, the properties of a particular type of contaminant and their behavior under certain geochemical conditions in different parts of the karst aquifers. The behavior of certain types of contamination in the karst aquifers was evaluated based on the results of the analysis and measurement of physical, physiochemical and chemical parameters of karst soil and filling of the epikarst zone. Adjustment of weights factors used in modeling the specific vulnerability of groundwater was performed according to geochemical conditions in various parts of the karstic hydrogeological system covered in red soil. The results of geochemical modeling using PHREEQC directly indicate the ionic form or the method of transport of chosen contaminant species. Arsenic and lead are predominantly related to the suspended soil and sediment particles and nitrates are migrable in the form of ions. Therefore, the mentioned contaminants can be transported over long distances without significant change. The obtained results have contributed significantly to the understanding of the soil and the epikarst zone storage capacity, not only in the Dinarides, but also in the areas with similar lithological and hydrogeological features. Steps have been taken in the last ten years to ensure improvements in quality of the spring waters of Jadra and Žrnovnica. A series of collectors and laggons were constructed along the Adriatic highway along with the closed water drainage system and sewage network in the Dugopolje area

Tla in sedimenti zaledja Proščanskega jezera kot možen terigen doprinos v jezerski sistem

The Plitvice Lakes National Park is in the northwestern part of the Dinaric Karst in central Croatia. An important role of the soil in the karst is to purify the waters before they reach the phreatic zone. The soil is also a zone of accumulation, transformation, retardation and dilution of a potential pollutant. Knowing soil mineralogical composition is an important factor in understanding fate and transport of contaminants throughout lakes system. Samples of soil, peat and stream sediment were collected in the Prošće lake catchment and partly in the assumed zone of influence, X-ray diffraction (XRD) and Fourier Transform Infrared spectroscopy (FTIR) analysis of samples was performed to determine dominant mineral species in samples. XRD analysis showed predominance of lowquartz, which was found in all samples, most often as dominant phase. Dolomite was found in half of the samples, almost always as a significant phase while calcite was dominant phase in one of the samples. In most of the samples, members of the feldspars and chlorites groups, as well as muscovite, were present as minor phases. The absorption bands in the range of 2800-3000 cm-1 due to the organic matter are visible in spectra of all samples. These minerals can enter lakes system by surface waters, primarily streams and overland flow during snow thawing and rain, and also in cases of shore erosion. Terrigenic input in lakes is small but cannot be neglected due to the longlasting preservation efforts of the Prošće Lake recharge area, and the Plitvice Lakes National Park in general, terrigenous intake still does not pose a threat to water quality and tufa production. Considering the analyzed samples and characteristics of detected soil constituents, soils and sediments in the Prošće Lake catchment have the ability to retain and purify water on its way to the lakes. On the other hand, in case of the possible contamination in the recharge area of the lakes system, the pollutants can enter the system adsorbed on the soil particles. Learning more about the soils surrounding lakes gives valuable insight into their possible influence on lakes water chemistry and adds one piece of the puzzle into understanding this kind of a natural phenomenon.Narodni park Plitviška jezera se nahaja v severozahodnem delu Dinarskega krasa v osrednji Hrvaški. Pomembna vloga tal v krasu je, da čistijo vodo, preden doseže freatično cono. Tla so tudi območje, kjer se potencialna onesnaževala kopičijo, preoblikujejo in redčijo. Tla ta onesnaževala tudi zadržijo. Poznavanje mineraloške sestave tal je pomemben dejavnik pri razumevanju prenosa onesnaževal v jezerskem sistemu. Tla, šoto in sedimente smo vzorčili v neposrednem zaledju in na vplivnem območju Prošćankega jezera. Mineralne vrste smo določili z rentgensko difrakcijo (XRD) in infrardečo spektroskopijo s Fourierjevo transformacijo (FTIR). Analiza XRD je pokazala, da v vzorcih prevladuje kremen, ki je bil v vseh vzorcih ugotovljen kot prevladujoč mineral. Dolomit je bil najden v polovici vzorcev, skoraj vedno kot pomemben mineral, medtem ko je kalcit prevladoval samo v enem od vzorcev. V večini vzorcev so bili v manjšini še glinenci, kloritni minerali in muskovit. Absorpcijski pasovi na območju 2800-3000 cm-1 so bili zaradi organske snovi vidni v vseh spektrih. Minerale lahko v jezerski sistem prinesejo površinske vode, predvsem med taljenjem snega in ob padavinah ali obalnih erozijskih procesi. Terigeni vnos je majhen, vendar ga zaradi dolgotrajnih prizadevanj za ohranitev in obnovo območja Prošćanskega jezera ni mogoče prezreti. Verjetno pa še ne ogroža kakovosti vode in nastajanja lehnjaka. Rezultati kažejo, da tla in sedimenti v zaledju Proščanskega jezera učinkovito zadržijo in čistijo vodo na poti do jezera. Vseeno lahko ob morebitnem onesnaženju v zaledju onesnaževala dosežejo jezerski sistem, če so adsorbirana na delce tal. Poznavanje tal v okolici in širšem zaledju jezera omogoča dragocen vpogled na njihov morebitni vpliv na kemijo vode v jezerih in prispeva k razumevanju tovrstnega naravnega pojava

Wastewater treatment in the city of Koprivnica

Based on the concept of sustainable development, water must be stored and protected for present and future generations. This also means saving the water through wastewater treatment. The primary role of the wastewater treatment plants is to treat wastewaters up to a satisfactory level of quality as close as possible to the natural state. The central wastewater treatment plant (WWTP) of the City of Koprivnica treats wastewater including the tertiary wastewater. Due to considerable fluctuations in wastewater volumes and loads, sequential batch reactor (SBR) technology was selected as the best solution for wastewater treatment. The final stage of treatment at the WWTP of the City of Koprivnica is the process of sludge treatment by aerobic stabilization, dehydration and MID-MIX technology, which produces a chemically inert powder – solidificate. Solidificate can be used in civil engineering or it can be disposed to landfill without environmental impact. This paper analyses the physical-chemical indicators of wastewater quality (chemical oxygen demand - COD, biological oxygen demand - BOD5, total nitrogen, total phosphorus, suspended matter) on wastewater samples from the WWTP of the City of Koprivnica in a period from 2014 to 2016. The results indicate that the treated wastewater has a satisfactory quality and that the WWTP of the City of Koprivnica works efficiently

CHEMICAL COMPOSITION OF BOTTLED WATER ON CROATIAN MARKET

The Ordinance on natural mineral, natural spring and table waters regulates the market of bottled water. The Directive on the quality of water intended for human consumption sets water quality standards and three categories of parameters (microbiological, chemical and indicator). Microbiological parameters show the degree of water pollution by microorganisms, while chemical parameters show the degree of water pollution by different chemical substances. Natural spring and natural mineral water have a certain chemical composition in which the concentrations of individual elements have the prescribed maximum allowable amount. If the concentrations of individual elements exceed the maximum allowed amount, they can have a harmful effect on the human body. All categories of bottled water (table, spring and mineral) can be carbonated and non-carbonated, depending on the carbon dioxide (CO2) content. Due to extracting and bottling of drinking water, in order to improve its quality, it is necessary continuously conduct analyses that prove the safety of drinking water

QUALITATIVE EVALUATION OF WASTEWATER TREATMENT PLANT PERFORMANCE BY NEURAL NETWORK MODEL OPTIMIZED BY GENETIC ALGORITHM

Negativan utjecaj nepravilnog odlaganja prikupljenih i pročišćenih otpadnih voda postao je neizbježan. Osim izgradnje uređaja za pročišćavanje otpadnih voda, za postizanje potrebnih ekoloških standarda postoji i potreba za ocjenjivanjem kontinuiranog rada sustava za pročišćavanje. U Iranu se pročišćene otpadne vode većinom koriste u poljoprivredi. Stoga korištenje otpadnih voda loših karakteristika kvalitete može ugroziti zdravlje. U ovoj studiji istražena je uspješnost modela neuronske mreže za predviđanje učinka uređaja za pročišćavanje otpadnih voda Perkandabad u Mashhadu u Iranu. U tu svrhu prvo su utvrđeni faktori koji utječu na parametar UBPK kao jedan od pokazatelja kvalitete efluenta. U sljedećem koraku učinkovitost uređaja za pročišćavanje je predviđena i ocijenjena pomoću genetskog algoritma i ulaznih faktora mreže. Najveći koeficijent korelacije za parametar UBPK iznosio je 0,89%. Rezultati pokazuju da među ulaznim parametrima u modelu najveći utjecaj na ovo predviđanje ima količina onečišćenja organskim tvarima.The adverse effects of improper disposal of collected and treated wastewater have become inevitable. To achieve the desired environmental standards, in addition to the construction of wastewater treatment plants, there is also a need to evaluate the continuous performance of treatment systems. In Iran, treated wastewater is mostly used in agriculture. Therefore, the use of wastewater with poor quality characteristics can endanger health. In this study, the neural network model\u27s efficiency was investigated to predict the performance of the Perkandabad wastewater treatment plant in Mashhad in Iran. To achieve this, first, the factors affecting the TBOD parameter were identified as one of the quality indicators of the effluent. In the next step, using a genetic algorithm and network input factors, the performance of the treatment plant was predicted and evaluated. The highest correlation coefficient for the TBOD parameter was 0.89%. The results show that among the input parameters in the model, the amount of organic matter pollution load has the greatest effect on this prediction

Recycling of Waste Rubber by Devulcanization Process

Posljednjih nekoliko desetljeća polimeri i polimerni materijali postali su neizostavni dio različitih grana industrije i svakodnevnog života. Zbog vrlo raširene upotrebe elastomera nastaju velike količine gumenog otpada, što je opterećenje za okoliš te zahtijeva posebne mjere zbrinjavanja kako bi se smanjio njihov negativan utjecaj na okoliš. Uzorci polimernih mješavina na bazi prirodnog (NR) i stiren-butadienskog kaučuka (SBR) pripremljeni su u dvije serije s ciljem ispitivanja mehaničkih (prekidna čvrstoća, prekidno istezanje, ispitivanje čvrstoće na zarez) i reoloških svojstava te krajnje upotrebe u proizvodnji gumenih pružnih prijelaza. Prva serija uzoraka pripremljena je s gumenim prahom, a u drugu seriju umiješan je devulkanizirani gumeni prah. Uzorci su miješani na laboratorijskom mikseru te homogenizirani na laboratorijskom dvovaljku, a proces prešanja proveden je na hidrauličkoj preši. Dobiveni rezultati ispitivanja mehaničkih i reoloških svojstava pokazali su da je za NR/SBR polimernu mješavinu koja bi se upotrebljavala za pružne prijelaze znatno bolja opcija dodatak gumenog praha koji je dodatno devulkaniziran. Ovo djelo je dano na korištenje pod licencom Creative Commons Imenovanje 4.0 međunarodna.Environmental protection requires constant improvement of quality and the environmental management system in accordance with the international standards and laws in order to reduce human impact on the environment and responsibly manage natural resources. Environmentally acceptable recycling of waste tires and other rubber products is one of the biggest ecological challenges today. Landfilling or dumping of tires causes serious long-term pollution. The lack of alternatives for tire recycling increases their disposal in landfills. Recycling is currently the most effective way to improve the sustainability of the environment. The purpose of this work was to determine the optimal composition of the rubber blend to be used for rubber track crossings production, and to examine the ratio of individual components, i.e., milled recycled tires, and milled and devulcanized tires in order to determine which option is more environmentally friendly and financially viable. In the first series of samples, recycled rubber powder (milled recycled tires) was mixed with a polymer blend of natural rubber and styrene-butadiene rubber, while the second series was milled and the devulcanized tires mixed with natural rubber and styrene-butadiene rubber. Rheological and mechanical properties of all the samples were measured according to appropriate standards. The results showed that an increase in the ratio of rubber powder increased the values of minimal rotation resistance and proportionally reduced the maximum rotation resistance. Minor deviations in the values of the vulcanization rate indicated that various ratios of added rubber powder had no significant effect on the rate of vulcanization of individual samples. The results of the viscosity measurement indicated a proportional increase in the values of initial rotation resistance with the increase in the ratio of added rubber dust compared to the samples prepared with milled and devulcanized rubber, whereby a proportional decrease in value was apparent. From the results of mechanical properties, observed was a reduction in tensile strength and elongation at break values for both series of tested samples. The same behaviour was also observed for the tear strength values. With the addition of different filler ratios, the hardness value for both series of prepared samples had reduced, while the values of the rebound elasticity differed slightly. Significant reduction in hardness value was evident for the samples prepared with the milled and devulcanized rubber powder, which could be attributed to the use of a softener during devulcanization of the material. It can be concluded that NR/SBR polymer blends can be mixed with various recycled rubber materials whereby the devulcanization process enables better mechanical and rheological properties, thus, used rubber tires can be effectively removed from the environment. This work is licensed under a Creative Commons Attribution 4.0 International License

Environmental geochemistry of the polymetallic ore deposits: Case studies from the Rude and the Sv. Jakob historical mining sites, NW Croatia

This paper presents the results of the sampling surveys carried out in order to evaluate the environmental impact of the Rude and the Sv. Jakob historical mining sites, NW Croatia. The studied polymetallic ore deposits are differing in the mineralogical and geochemical features as well as in the host rock lithology. The Rude Fe-Cu-Pb-Zn-Ba deposit is hosted by Permian siliciclastic sediments. Siderite, hematite, galena, sphalerite, chalcopyrite, pyrite, barite and gypsum are the major ore minerals, whereas quartz is the principal gangue mineral. The Sv. Jakob Pb-Zn-Ag deposit occurs in the Middle Triassic dolostone. The most abundant ore minerals are galena, sphalerite and pyrite. Calcite and quartz represent the principal gangue minerals. Although the deposits represent the potential sources of numerous toxic metals, the pollution of the drainage streams and associated stream sediments was not recorded. The studied mining sites are characterized by the high carbonate/sulfide ratios responsible for the alkaline character of the drainage streams. Consequently, the mining sites have very low potential for generation of acid mine drainage as well as very low potential for leaching of heavy metals into the drainage systems. Furthermore, the presented study revealed that the populated areas (stream waters with decreased redox potential, increased organic matter content, high NO3-, NH4+ and PO43- concentrations; stream sediments enriched in exchangeable Pb and Zn) and the Sava river alluvium (overflowing streams enriched in Hg) represent bigger environmental threat than the investigated polymetallic ore deposits. </span

Bestimmung der Trihalogenmethan konzentration in Wasse

Zdravstveno ispravna voda za ljudsku potrošnju mora biti kemijski i mikrobiološki ispravna te dobrih senzorskih svojstava. Dezinfekcija je najvažnija faza u pripremi vode za piće, a najčešće upotrebljavano dezinfekcijsko sredstvo je klor. Tijekom kloriranja, klor može reagirati s prisutnim organskim tvarima stvarajući pritom čitav niz nusprodukata dezinfekcije među kojima su i trihalometani. Trihalometani su lako hlapljivi halogenirani ugljikovodici koji imaju negativno djelovanje na centralni živčani sustav, jetru i bubrege. Koncentracije triklormetana (kloroforma) CHCl3, bromdiklormetana CHBrCl2, dibromklormetana CHBr2Cl i bromoforma CHBr3 te ukupnih trihalometana određena je u uzorcima vode s vodocrpilišta Bartolovec u Varaždinskoj županiji metodom plinske kromatografije u za vremensko prazdoblje od 2016. do 2019. godine. Rezultati analize pokazali su da u promatranom periodu koncentracije trihalometana nisu bile iznad dozvoljene vrijednosti od 100 μg/L te da je voda zdravstveno ispravna i udovoljava svim važećim propisima.Health safety of water intended for human consumption means that water has to be chemically and microbiologically adequate and have good sensory properties. Disinfection is the most important phase in the preparation of water for drinking purposes, and the most frequently used disinfectant is chlorine. In the process of chlorination, chlorine may react with present organic matter and form a number of disinfection by-products, one of which are trihalomethanes. Trihalomethanes are highly volatile halogenated hydrocarbons that have adverse impact on the central nervous system, liver and kidneys. The concentrations of trichloromethane (chloroform) CHCl3, bromodichloromethane CHBrCl2, chlorodibromomethane CHBr2Cl, bromoform CHBr3 and total trihalomethanes were determined on water samples from the water abstraction site Bartolovec in the Varaždin County for the 2016-2019 period by using gas chromatography. The analysis results showed that the trihalomethane concentrations in the observed period were not above the permissible value of 100 μg/L, i.e. that water was safe for human consumption and met all applicable regulations.Das Wasser für den menschlichen Gebrauch muss den chemischen und mikrobiologischen Anforderungen entsprechen und gute sensorische Eigenschaften haben. Desinfektion ist die wichtigste Phase in der Trinkwasseraufbereitung, und Chlor gehört zu den am meisten verwendeten Desinfektionsmitteln. Bei der Chlorierung kann Chlor mit organischen Stoffen reagieren, wobei eine Reihe von Nebenprodukten des Desinfektionsverfahrens entsteht, darunter auch Trihalogenmethane. Trihalogenmethane sind leichtflüchtige halogenierte Kohlenwasserstoffe, die schädliche Wirkungen auf zentrales Nervensystem, Leber und Nieren haben. Die Konzentrationen von Dichlormethan (Chloroform) CHCl13, Bromtrichlormethan CHBrCl2, Dibromchlormethan CHBr2Cl, Bromoform CHBr3 und Gesamttrihalogenmethane wurden mittels Gaschromatographie in Wasserproben bestimmt, die aus der Wassergewinnungsanlage Bartolovec im Varaždin-Bezirk im Zeitraum vom 2016 bis 2019 entnommen wurden. Die Analysenergebnisse zeigten, dass im beobachteten Zeitraum die Trihalogenmethan-Konzentrationen nicht oberhalb des zulässigen Wertes von 100 μg/L lagen und dass das Wasser gesund ist und allen geltenden Vorschriften entspricht