natgillin/translations-raw huggingface dataset:
Since at temperature of +10 °C and +20 °C the viscous component in asphalt mixture is dominates and the relaxation characteristics of the asphalt mixture reduce inducted thermal stress, the difference between TSRST at starting temperatures of +10 °C and +20 °C is negligible. 
Kako je pri temperaturama od +10 °C i +20 °C viskozna komponenta dominantna u asfaltnoj mješavini, te kako karakteristike popuštanja asfaltne mješavine umanjuju inducirano toplinsko naprezanje, razlika između ispitivanja TSRST pri početnim temperaturama od +10 °C i +20 °C može se smatrati zanemarivom.
The results of TSRST, comparison between ZAG Ljubljana and TU Wien, shows that there is a considerable difference, although both Institutes carried out TSRST in accordance to the standard EN 12697-46. 
Rezultati usporedbe rezultata ispitivanja koji su postignuti u laboratorijima ZAG - Ljubljana i TU Wien pokazuju da postoje značajne razlike, iako su oba laboratorija obavila ispitivanja u skladu s normom EN 12697-46.
In this case the both curves TU Wien and ZAG run apart at temperature around 5 °C, but at colder temperature run parallel. 
U ovom slučaju obje se krivulje, TU Wien i ZAG, razilaze kad je temperatura oko 5 °C, ali su paralelne pri nižim temperaturama.
At a tensile stress of 1.0 MPa the temperature difference between curves is 5-6 °C. 
Kod vlačnog naprezanja od 1,0 MPa, temperaturna razlika između krivulja iznosi 5-6 °C.
The relaxation zone at TU Wien is longer as ZAG and in the elastic zone the slope of curve is little higher at TU Wien. 
Zona popuštanja je u laboratoriju TU Wien duža nego u laboratoriju ZAG dok je u elastičnoj zoni nagib krivulje nešto viši u laboratoriju TU Wien.
All of these differences could be due to various factors (etc. gluing samples, equipment). 
Sve te razlike mogle bi biti uvjetovane raznim faktorima (npr. lijepljenje uzoraka, oprema).
Use of sludge generated at WWTP in the production of cement mortar and concrete 
Korištenje mulja s UPOV-a u proizvodnji cementnog morta i betona
Key words: wastewater, WWTP, sludge disposal, ash, cement mortar, concrete 
Ključne riječi: otpadne vode, UPOV, zbrinjavanje mulja, pepeo, cementni mort, beton
Korištenje mulja s UPOV-a u proizvodnji cementnog morta i betona 
Use of sludge generated at WWTP in the production of cement mortar and concrete
U radu je opisana problematika vezana uz generiranje i zbrinjavanje mulja s UPOV-a (uređaja za pročišćavanje otpadnih voda) u Hrvatskoj. 
Problems relating to disposal of sludge accumulating at waste-water treatment plants (WWTP) in Croatia are described in the paper.
Poseban osvrt je dan na mogućnost i opravdanost korištenja pepela dobivenog spaljivanjem mulja. 
The possibility and adequacy of using ash obtained through incineration of sludge is considered.
Naglasak je stavljen na ugradnju pepela u betonskoj industriji, pri proizvodnji cementnog morta i betona. 
A special emphasis is placed on the significance of ash in concrete industry during production of cement mortar and concrete.
U radu su opisani rezultati dosada provedenih istraživanja u okviru svjetske prakse, s primarnim osvrtom na utjecaj ugradnje pepela na karakteristike cementnog morta i betona. 
Results of worldwide research conducted so far are described, with indications about the ways in which ash use influences properties of cement mortar and concrete.
Ključne riječi: otpadne vode, UPOV, zbrinjavanje mulja, pepeo, cementni mort, beton 
Key words: wastewater, WWTP, sludge disposal, ash, cement mortar, concrete
Domagoj Nakić, MCE 
Domagoj Nakić, mag. ing. aedif.
University of Zagreb Faculty of Civil Engineering dnakic@grad.hr 
Sveučilište u Zagrebu Građevinski fakultet dnakic@grad.hr
Prof. Aleksandra Anić-Vučinić 
Aleksandra Anić-Vučinić, dipl.ing.preh.teh.
1. Introduction and legal framework 
1. Uvod i zakonski okviri
Proper water management is one of basic prerequisites for the development of any region. 
Osiguranje prikladnog gospodarenja vodama jedan je od temeljnih preduvjeta za razvoj svakog područja.
In addition, the need is now increasingly felt for proper protection of our environment, in the scope of which a special emphasis is placed on the protection of biodiversity and human health. 
Isto tako, u današnje vrijeme sve je veća potreba za zaštitom okoliša, u sklopu koje posebno mjesto zauzima očuvanje bioraznolikosti i zaštita ljudskog zdravlja.
This is why proper disposal of waste waters is ranked among high-priority activities in the scope of adequate water management policies. 
Stoga se primjereno postupanje s otpadnim vodama svrstava u prioritetne aktivnosti prikladnoga gospodarenja vodama.
After analysis of the existing situation in the municipal services sector in Croatia [1-6], it can be concluded that, among all water management problems existing in Croatia, the greatest attention is now placed on adequate disposal of waste waters. 
Uzimajući u obzir postojeće stanje komunalnog sektora u Hrvatskoj [1-6], može se zaključiti da u cjelokupnoj problematici o gospodarenju vodama u Hrvatskoj najviše je pozornosti usmjereno na pravilno postupanje s otpadnim vodama.
This statement is further backed by the fact that only about 43 % of Croatian population is currently connected to a public sewerage system [6]. 
Tome ide u prilog činjenica da je u Hrvatskoj danas samo oko 43 % stanovništva priključeno na javnu kanalizacijsku mrežu [6].
The situation is even less favourable with regard to connection to waste-water treatment plants (WWTP). 
Još je nepovoljnija situacija s priključenjem na uređaje za pročišćavanje otpadnih voda.
As in other EU countries this Directive with stricter quality requirements entered into force in 2005, Croatia now lags considerably behind most EU countries in the sphere of waste water purification practices. 
Budući da je ova Direktiva u ostalim zemljama EU na snagu stupila 2005., u području implementacije strožih zahtjeva za kvalitetom, Hrvatska danas u području pročišćavanja otpadnih voda u značajnoj mjeri zaostaje za većinom zemalja EU-a.
In an attempt to ensure compliance with provisions of the EU's Water Framework Directive, active measures are currently being taken relating to construction of comprehensive waste water drainage systems, with the corresponding waste water purification plants for agglomerations in excess of 10,000 EP. 
U nastojanjima za usklađivanjem s odredbama Okvirne direktive o vodama Europske unije u tijeku je aktivno poduzimanje određenih mjera vezanih za izgradnju cjelovitih sustava odvodnje otpadnih voda s pripadajućim uređajima za pročišćavanje otpadnih voda (UPOV-i) za aglomeracije veće od 10.000 ES.
In other words, by joining the European Union, Croatia has assumed the obligation to build by 2018 all WWTPs with the capacity of more than 10,000 EP, which will finally result in the realization of the WWTPs for the total load of approximately 4,500,000 EP [8]. 
Drugim riječima, pristupanjem Europskoj uniji, Hrvatska se obvezala do 2018. godine izgraditi sve UPOV-e kapaciteta većeg od 10.000 ES, što će u konačnici rezultirati puštanjem u pogon UPOV ukupnog opterećenja oko 4.500.000 ES [8].
On the one side, construction of WWTPs exerts a favourable influence on the environment through reduction of waste substances that are released into environment but, on the other side, some new problems are encountered in the purification process, namely in the form of generation of significant quantities of sludge that must be adequately disposed. 
Izgradnja UPOV-a s jedne strane predstavlja pozitivan utjecaj na okoliš jer će se smanjiti količina otpadnih tvari koje se ispuštaju u prijamnike, ali se istovremeno u procesu pročišćavanja pojavljuju novi problemi vezani uz stvaranje značajnih količina mulja s kojim treba primjereno postupiti.
According to Croatian legislation, the sludge generated at WWTPs is treated as non-hazardous waste that should be adequately treated and disposed into environment. 
Prema hrvatskom zakonodavstvu, mulj s UPOV-a tretira se kao neopasni otpad koji treba na odgovarajući način dodatno obraditi i odložiti u okoliš.
Current practices with regard to planning and construction of WWTPs are primarily oriented toward the water line, and attempts are made to meet the combined approach criterion according to which purified water must meet some specific purification requirements, and the discharge of purified water must not disturb natural biological balance in receiving water bodies (watercourses, channels, seas, etc.) [9]. 
Dosadašnja praksa planiranja i izgradnje UPOV-a uglavnom je usmjerena na vodu, nastojeći dostignuti kriterij objedinjenog pristupa prema kojem pročišćena voda mora zadovoljiti propisane i potrebne uvjete učinkovitosti pročišćavanja, a ispuštanje pročišćene vode ne smije narušiti prirodnu biološku ravnotežu u prijamnicima (vodotoci, kanali, more i dr.) [9].
The sludge disposal problem has not so far been fully solved in Croatia, nor has it been properly addressed through regulations, instructions or guidelines. 
Do danas u Hrvatskoj nije cjelovito riješeno kako postupiti s muljem, niti je to određeno propisima, uputama ili smjernicama.
As the construction of WWTPs gains in intensity in Croatia, the sludge disposal issue will increasingly become an encumbrance for public utility companies and local self-government units that operate local wastewater drainage and purification systems. 
Kako gradnja UPOV-a u Hrvatskoj postaje sve intenzivnija, način postupanja s muljem znatno će opterećivati rad komunalnih poduzeća i jedinica lokalne samouprave, koji upravljaju sustavima odvodnje i pročišćavanja otpadnih voda.
The construction of WWTPs may be considered completed by the authorities only after a solution for final disposal of sludge has been provided, i.e. after compliance with all environmental protection measures has been demonstrated. 
Treba istaknuti kako se za UPOV-e kod kojih nije riješeno konačno odlaganje mulja, smatra da njihova izgradnja nije završena te da nisu poduzete sve potrebne mjere o zaštiti okoliša.
This is directly related to obligations toward the EU because, in case all requirements - including adequate sludge disposal - are not met, significant funds will have to be paid in form of fines. 
To se neposredno odnosi i na obveze prema EU, pa će se ako nisu zadovoljeni svi uvjeti, tj. kako postupiti s muljem, plaćati značajni novčani iznosi u obliku kazni.
In 2007, the total annual generation of sludge originating from WWTPs amounted to almost 17,000,000 t DM in the USA and EU (namely 7,000,000 t in the USA and 10,000,000 t in the EU) [10]. 
Prema podacima iz 2007. godine, ukupna godišnja proizvodnja mulja s UPOV-a u SAD-u i u EU iznosila je gotovo 17.000.000 t ST (7.000.000 t u SAD-u i 10.000.000 t u EU-u) [10].
Nevertheless, the quantities of sludge as a by-product of waste water purification are constantly on the rise all over the world. 
Međutim, količine mulja, koji je nusproizvod pročišćavanja otpadnih voda, neprestano se povećavaju na svjetskoj razini.
The annual sludge generation in 27 EU countries, including the sludge generation forecast until 2020, is presented in Figure 1 [11]. 
Na slici 1. prikazan je smjer godišnje proizvodnje mulja u 27 zemalja EU-a, predviđajući i kako će rasti do 2020. godine [11].
Almost 50 % of sludge generated in 2009 was used in agriculture in countries such as Spain, Great Britain and France, while the rest was either deposited on landfills or incinerated. 
U zemljama poput Španjolske, Velike Britanije i Francuske gotovo se 50 % mulja nastalog 2009. godine koristilo u poljoprivredi, a ostatak se odlagao na odlagalištima ili spaljivao.
Annual sludge generation in WWTPs in 27 EU countries [11] Sludge generated at the WWTPs that have been built so far in Croatia is deposited on solid waste disposal sites. 
Na UPOV-ima koji su do danas izgrađeni u Hrvatskoj mulj se odlaže na odlagalištima krutog otpada, od čega se vrlo mali dio koristi u poljoprivredi, a za ostalo se ne može sa sigurnošću utvrditi gdje i kako završava.
Out of the total quantity of sludge, very little is used in agriculture and, for the 
Općenito, problemu odgovarajućeg postupanja s muljem u Hrvatskoj, sve donedavno, nije se pridavala veća pažnja.
major part of this sludge, it can not be said with certainty where and how it is disposed. 
Korištenje mulja s UPOV-a u proizvodnji cementnog morta i betona
It is indicated in the same document that waste disposal sites will not be allowed to accept, inter alia, "municipal waste in case the mass of its biodegradable component exceeds 35 % of the total mass". 
istom se dokumentu navodi da je na odlagalištima otpada zabranjen prihvat, između ostalog i: "komunalnog otpada ukoliko mu masa biorazgradive komponente premašuje 35 % od ukupne mase".
The mass of the biologically stabilized sludge always exceeds 35 %wt of biodegradable matter. 
Biološki stabiliziran mulj sadrži uvijek više od 35 masenih postotaka biorazgradive tvari.
As the quantities of sludge waste to be disposed on landfill sites is limited by European directives, namely by the EU Sewage Sludge Directive (86/278/EC), EU Landfill Directive (99/31/EC), and the EU Waste Incineration Directive (2000/76/ EC), and as the EU Waste Framework Directive 2008/98/EC favours waste reuse (recycling) over other solutions, it is evident that the generation of such vast quantities of sludge originating from WWTPs will require an appropriate response. 
S obzirom na to da je prema propisima Direktive o mulju (86/278/EC), Direktive o odlagalištima otpada (99/31/EC) i Direktive o spaljivanju otpada (2000/76/EC) ograničena količina otpadnog mulja koja se može prihvatiti na odlagalištima te da se prema Direktivi o otpadu 2008/98/EC daje prednost ponovnom korištenju (recikliranju) otpada u odnosu na ostala rješenja, jasno je da će nastanak golemih količina mulja s UPOV-a zahtijevati odgovarajuće gospodarenje s muljem.
Selection of an optimum sludge treatment procedure at WWTPs will inter alia depend on the final sludge disposal, and this final disposal must be taken into account already during construction of such plants. 
Odabir optimalnog postupka obrade mulja na UPOV-ima ovisi između ostalog i o konačnom gospodarenjem s muljem pa je već kod izgradnje uređaja to nužno uzeti u obzir.
Sludge incineration is compliant with the Appendix 1: Waste Disposal Procedures (D10) of the sustainable Waste Management Act (OG No. 94/13). 
Spaljivanje mulja u skladu je s propisom u Dodatku 1 (Postupci s otpadom (D10) Zakona o održivom gospodarenju otpadom (NN 94/13)).
The total sludge mass reduces considerably (up to 85 %) through incineration [15] and the same applies to the volume of the final waste matter, which facilitates further use of sludge and the newly created product (boiler/hearth ash). 
Spaljivanjem mulja znatno se smanjuje ukupna masa mulja (do 85 %) [15] i volumen konačne otpadne tvari, čime se olakšava daljnje gospodarenje muljem i novonastalim proizvodom (pepelom iz kotlovnice/ložišta).
In addition, toxic organic compounds become disintegrated by thermal action, disagreeable odours are minimised, and the sludge energy can be put to good use [16]. 
Osim toga, termički se razgrađuju toksični organski spojevi, minimiziraju se neugodni mirisi i omogućuje koristiti energetska vrijednost mulja [16].
However, a byproduct in form of boiler ash and fly ash from filter is generated even during the sludge incineration procedure, and it also has to be disposed in an appropriate way. 
Međutim, i u sklopu postupka spaljivanja muljeva javljaju se nusproizvodi u obliku pepela iz kotlovnice i lebdećeg pepela iz filtra, s kojima u konačnici treba također postupiti na odgovarajući način, a čije količine nisu zanemarive.
It should be noted that the quantities of such ash are far from negligible, with boiler ash quantities being about ten times greater compared to quantities of fly ash from filter. 
Pritom se napominje da su količine pepela iz kotlovnice oko deset puta veće u odnosu na količine lebdećeg pepela iz filtra.
A schematic of sludge production in Croatia after 2018 is presented in Figure 2. 
Izgradnjom novih i rekonstrukcijom postojećih UPOV-a navedena brojka će se konstantno povećavati.
Estimated production of sludge and ash from WWTPs in Croatia after 2018 
Procjena proizvodnje mulja i pepela s UPOV-a u Hrvatskoj nakon 2018. godine
From the perspective of sustainable development, the waste water treatment cycle is almost fully completed by the use of sludge, and the quantities of waste matter generated in the process, which still have to be disposed into environment, are quite negligible. 
U okvirima održivog razvoja, korištenjem mulja gotovo u potpunosti se zatvara ciklus pročišćavanja otpadnih voda, pri čemu se stvaraju zanemarive količine otpadne tvari koje je potrebno odložiti u okoliš.
In this paper, a primary focus will be placed on the use of ash in concrete industry, as concrete is the world's most widely used artificially obtained material. 
U radu će se prije svega razmotriti mogućnosti upotrebe pepela u betonskoj industriji, s obzirom na to što je beton najčešće korišten umjetno dobiveni materijal u svijetu.
Some practical results of research conducted in various countries will be described, and comparison will be made with the results obtained in Croatia. 
Opisat će se neki od rezultata dosada provedenih istraživanja u okviru svjetske prakse, te će se dati usporedba s rezultatima dobivenim u Hrvatskoj.
2. Composition of ash obtained by incineration of sludge 
2. Sastav pepela dobivenog spaljivanjem mulja
In concrete industry, the use of ash obtained by incineration of sludge is primarily related to the ash from boilers. 
Mogućnost upotrebe pepela dobivenog spaljivanjem mulja u betonskoj industriji uglavnom se odnosi na pepeo iz kotlovnice.
Ash is a powdery material with some sand size grains, and with a negligible content of organic matter and moisture. 
Pepeo je praškasti materijal s nešto čestica veličine zrna pijeska te sa zanemarivim udjelom organske tvari i vlage.
An accurate range of ash grain sizes depends on the sludge treatment procedure, on the content of industrial water in waste water, and on the type of drainage system [18]. 
Točan raspon veličina čestica pepela ovisi o postupcima obrade mulja, udjelu industrijskih voda u otpadnoj vodi i tipu sustava odvodnje [18].
The irregular morphology and porous structure of ash grains, and its large specific surface, result in a greater need for water when the ash is used as a replacement in various types of cement mortars and concretes [10]. 
Nepravilna morfologija i porozna struktura čestica pepela te njegova velika specifična površina utječu na veću potrebu za vodom kada se pepeo koristi kao zamjenski dodatak u cementnim mortovima i betonima [10].
Principal chemical elements contained in ash obtained during thermal treatment of sludge are the silicon (Si), aluminium (Al), calcium (Ca), and phosphorus (P). 
Glavni kemijski elementi sadržani u pepelu kao nusproizvodu termičke obrade mulja jesu silicij (Si), aluminij (Al), kalcij (Ca) i fosfor (P).
Density of ash obtained by incineration of sludge from Karlovac WWTP at various temperatures (800, 900, and 1000°C) [8] 
Gustoća pepela dobivenog spaljivanjem mulja s karlovačkog UPOV-a pri različitim temperaturama (800, 900 i 1000°C) [8]
However, some research projects are still in progress, and new projects of this type 
Stoga rezultate nekih istraživanja o muljevima, čiji se sastav razlikuje od muljeva generiranih na području Hrvatske,
Incineration temperature 
Temperatura spaljivanja
Density of ash 
Gustoća dobivenog pepela
Oxide content in ash [mas. %] 
Udio oksida u pepelu [mas. %]
Range of values (literature review) 
Raspon vrijednosti (pregled literature)
WWTP Karlovac 
UPOV Karlovac
WWTP Koprivnica 
UPOV Koprivnica
WWTP Zagreb 
UPOV Zagreb
Chemical composition of ash obtained by incineration of sludge [8, 10, 16, 23, 28, 31, 34-44] 
Kemijski sastav pepela dobivenog spaljivanjem mulja [8, 10, 16, 23, 28, 31, 34-44]
are constantly being initiated. 
treba uzeti s određenim oprezom.
This points to the great significance of the ash quality and composition testing under various circumstances, as related to the quality of wastewater and technological processes used at the WWTP. 
Isto tako, sastav mulja i pepela koji se generira na UPOV-u u znatnoj mjeri ovisi o tehnološkom procesu pročišćavanja vode i same obrade mulja.
That is why the results of some research conducted with the sludge whose composition differs from that of the sludge generated in the territory of Croatia should be taken with some caution. 
Usporedbe radi, u istoj tablici, dani su rasponi vrijednosti masenih udjela istih oksida u pepelu dobivenom spaljivanjem mulja s triju UPOV-a u Hrvatskoj (karlovačkog, koprivničkog i zagrebačkog) [8].
To enable comparison, the same table provides weight percent values of the same oxides in the ash obtained by incinerating sludge from three WWTP in Croatia (Karlovac, Koprivnica and Zagreb [8]. 
Udio sastojaka prisutnih u pepelu u tragovima (ili u manjim udjelima) može još značajnije varirati zbog utjecaja obilježja industrijske aktivnosti u tome području.
Table 2 shows that there are considerable differences in ash composition. 
3. Spaljivanje mulja
These differences primarily depend of the properties of wastewater, on the sludge treatment technology, incineration temperatures, etc. For instance, the patented "MIDMIX" sludge treatment technology is used at the Koprivnica WWTP. 
Ocijeđeni mulj, s udjelom suhe tvari u rasponu 18 - 35 mas. % ST, prije konačnog spaljivanja se uobičajeno suši radi povećanja energetske učinkovitosti pri spaljivanju.
This technology is based on addition of considerable quantities of lime during sludge treatment, and so the ash obtained from this sludge has a much higher CaO content. 
Tako osušeni mulj, s udjelom 75 - 90 mas. % ST, potom se uvodi u peći za spaljivanje gdje nastaje pepeo u obliku fino granuliranog otpadnog materijala.
Ranges of values for oxides contained in ash from the three WWTPs in Croatia are due to different sludge incineration temperatures (800, 900 and 1000⁰C). 
Prilikom spaljivanja mulja s UPOV-a ne samo da nastaje pepeo koji je moguće višestruko iskoristiti, već se u tom procesu odvija cjelokupna termička razgradnja organskih, ali i najvećeg dijela anorganskih zagađivala [47].
It has however been observed that the proportion of principal oxides contained in ash may vary considerably even at plants operating under similar conditions [45, 46]. 
Kalorijska vrijednost mulja slična je onoj smeđeg ugljena, ali treba imati na umu činjenicu da je to kalorijska vrijednost organskog dijela mulja, dok anorganski dio nema kalorijsku vrijednost.
The incineration of sludge originating from WWTPs does not only result in creation of ash that can be used in a number of ways but. 
Od ostalih tipova koristi se modularna spalionica [40] i električna prigušena peć (engl. electrical muffle furnace) [16].
It also results in a thorough thermal disintegration of organic and most inorganic pollutants [47]. 
Prema slici 3., mulj i vrući zrak (500 - 600 °C) uvode se u peć za izgaranje.
In this stabilized and dehydrated state, the calorific value of sludge ranges from 12 to 20 MJ/kg [36]. 
Zaostale anorganske tvari se, zajedno s plinovima, iznose iz peći u obliku finih čestica.
Several incinerator types are currently used for the incineration of sludge. 
Nastali pepeo (ISSA) se, nakon prolaska kroz izmjenjivač topline (bojler), zadržava u vrećastim ili elektrostatičkim filtarskim uređajima.
Most widely used systems are the fluidized bed incinerators [10, 15, 18, 30, 39] whose schematic is given in Figure 3. 
Prije ispuštanja u atmosferu, nastali se plinovi tretiraju u skladu s EU direktivom o spaljivanju otpada (2000/76/EU) [18].
Other types currently in use are modular furnaces [40] and electrical muffle furnaces [16]. 
Na slici 4. shematski su prikazani fizikalni i kemijski procesi tijekom spaljivanja mulja.
The sludge is incinerated in the furnace for 1 to 2 hours. 
Dražen Vouk, Marijana Serdar, Domagoj Nakić, Aleksandra Anić-Vučinić
The ash formed in this way (ISSA) passes through the heat exchanger (boiler), and is retained in bag filters or electrostatic filtering devices. 
Pri temperaturi iznad 900 - 950 °C, ovisno o izvorima, dolazi do stvaranja klinkera, odnosno povećanja kristalizacije i slabljenja pucolanskih svojstava pepela [15, 16, 31].