Recent technological developments have led to a significant increase in energy consumption in daily life. The search for alternative means of energy production has become an important task for ...applied sciences and modern technology. Hydrogen technology has great potential as a source of clean energy. The production of green hydrogen is a desirable and beneficial way to contribute to the decarbonization of the energy sector. In response to the demand for environmentally friendly and economically feasible approaches, biohydrogen production from waste materials has recently attracted interest. Waste materials from industrial or municipal production can be used as low-cost substrates for biohydrogen production through microbial degradation. Green energy needs could be met through a form of sustainable development that moves hand in hand with the harnessing of the microbial potential of waste biomass. Reuse of waste materials leads to pollution reductions and energy recycling. The aim of this review is to provide informative insights for researchers and engineers to help them better understand microbial biohydrogen production from low-cost waste substrates, such as industrial wastewater and waste activated sludge.
Discovery of Plastics-degrading Enzymes Mehmet Mervan Çakar; Marija Vuković Domanovac; Zvjezdana Findrik Blažević
Kemija u industriji,
07/2023, Letnik:
72, Številka:
7-8
Journal Article
Recenzirano
Odprti dostop
Plastics are highly advanced materials that have a vast array of applications and are produced globally in an approximate amount of 350 to 400 million tons every year. Nevertheless, there are serious ...concerns about plastic waste and pollution as a result of the misuse and lack of control of their use in industries, including packaging, transportation, manufacturing, and agriculture. Approximately 1,000 years are required for plastic bags to decompose efficiently. Additionally, CO2 and dioxins are released into the atmosphere by burning plastics, and they contribute to global warming. The Earth’s environment is overwhelmed with waste, mostly from poor recycling practices and low circular usage, resulting in millions of tons of waste generated annually. To combat this, new technologies for recycling post-consumer plastics are desperately needed to decrease plastic waste and improve the environment, while also finding ways to utilise these materials. Due to the inadequate disposal methods currently available for plastic waste, there has been increased interest in the use of microorganisms and enzymes designed for the biodegradation of non-degradable synthetic polymers via biocatalytic depolymerisation indicating that plastics treatment and recycling can be more efficient and sustainable.
In this paper, two different types of biowaste composting processes were carried out – composting without and with bioaugmentation. All experiments were performed in an adiabatic reactor for 14 days. ...Composting enhanced with bioaugmentation was the better choice because the thermophilic phase was achieved earlier, making the composting time shorter. Additionally, a higher conversion of substrate (amount of substrate consumed) was also noticed in the process enhanced by bioaugmentation. A mathematical model was developed and process parameters were estimated in order to optimize the composting process. Based on good agreement between experimental data and the mathematical model simulation results, a three-level-four-factor Box-Behnken experimental design was employed to define the optimal process conditions for further studies. It was found that the air flow rate and the mass fraction of the substrate have the most significant effect on the composting process. An improvement of the composting process was achieved after altering the mentioned variables, resulting in shorter composting time and higher conversion of the substrate.
Pripremom i konzumiranjem hrane u kućanstvima te održavanjem zelenih javnih površina, okućnica i vrtova nastaje biootpad koji je potrebno odvojeno sakupiti i obraditi u skladu s propisima iz područja ...zaštite okoliša, odnosno ciljevima gospodarenja otpadom u Republici Hrvatskoj. Na temelju sastava i količine komunalnog otpada procijenjene su godišnje količine biootpada razmatranog područja. Iz ulaznih podataka o količini biootpada te ulaznih procesnih podataka koji su relevantni za provedbu biološke obrade biootpada u aerobnim uvjetima, dimenzionirana je potrebna oprema i prostor uvažavajući dinamiku procesa i potrebne tehnološke operacije. U ovom radu je analizirano pretpostavljeno područje od oko 77 000 stanovnika te je pretpostavljeno da to stanovništvo proizvede oko 3 641 t god−1 biootpada. Biološkom obradom odvojeno sakupljenog biootpada u aerobnim uvjetima koja se provodi na kompostani malog kapaciteta procjenjuje se proizvodnja oko 2 575 t god−1 zrelog komposta, što predstavlja smanjenje ulazne mase biootpada od oko 34,1 %, odnosno volumena za oko 50,5 %. Troškovi izgradnje objekata i nabave opreme procjenjuju se na oko 16 305 000 kn (2 174 000 EUR), a ukupni troškovi rada postrojenja s uračunatom amortizacijom na oko 625 kn/t (83 EUR/t) ulaznog biootpada.
U ovom je radu procijenjen energetski potencijal miješanog komunalnog otpada koji preostaje nakon ispunjavanja propisanih i planiranih ciljeva gospodarenja komunalnim otpadom, nakon obrade u ...postrojenjima za mehaničko-biološku obradu. Tom obradom proizvodi se kruto gorivo iz otpada ili električna i toplinska energija u slučaju proizvodnje bioplina anaerobnom obradom biorazgradive frakcije otpada.
Radi analize, 2026. je pretpostavljena kao godina izgradnje centara za gospodarenje otpadom. Ukupni energetski potencijal koji je moguće iskoristiti oporabom otpada iznosi oko 5,3 PJ, odnosno iznosi oko 3,71 % od količine energije iz sektora ukupne opće potrošnje energije za 2018. godinu.
Ovo djelo je dano na korištenje pod licencom Creative Commons Imenovanje 4.0 međunarodna .
Fitoremedijacija – pregled stanja i perspektiva Milčić, Nevena; Findrik Blažević, Zvjezdana; Vuković Domanovac, Marija
Kemija u industriji,
10/2019, Letnik:
68, Številka:
9-10
Journal Article
Recenzirano
Odprti dostop
Remedijacija tala onečišćenih kompleksnim mješavinama organskih tvari i teških metala jedan je od najvećih izazova obnavljanja okoliša. Fitoremedijacija je naziv za skup postupaka koji upotrebljavaju ...biljke, njihove enzime i prisutne mikroorganizme iz zone korijenja za izolaciju, transport, detoksikaciju i mineralizaciju ksenobiotika, čime se smanjuje njihova koncentracija, pokretljivost ili toksični učinci. Fitoekstrakcija, fitostabilizacija, fitovolatizacija, fitorazgradnja i rizorazgradnja imaju velik potencijal za nedestruktivnu remedijaciju tala, što pokazuju brojna istraživanja u laboratorijskom mjerilu. Kako bi fitoremedijacija postala pouzdana tehnologija za širok spektar primjena u većem mjerilu, potrebno je ulagati resurse u nova istraživanja s ciljem boljeg razumijevanja procesa u cjelini, posebice na genetičkoj i biokemijskoj razini.
Remediation of soils contaminated with complex mixtures of organic compounds and heavy metals is one of the greatest challenges of environmental renewal. Phytoremediation is the name for a set of techniques that employ plants, their enzymes, and associated microorganisms in the root zone for isolation, transport, detoxification, and mineralization of xenobiotics in the soil, thereby reducing their concentration, mobility or toxic effects. Phytoextraction, phytostabilization, phytovolatization, phytodegradation, and rhizodegradation have a great potential for non-destructive remediation of soils as shown by numerous laboratory-scale studies. In order for phytoremediation to become a reliable technology for a wide range of applications at a larger scale, resources need to be invested in a new research with an aim to better understand the process as a whole, especially at the genetic and biochemical levels.
Bioremedijacija se koristi potencijalom mikroorganizama pri uklanjanju onečišćenja iz okoliša. Metabolički putovi kojima se onečišćujuća tvar razgrađuje u manje toksične tvari vrlo su kompleksni. ...Naprednim tehnikama molekularne biologije mehanizmi bioremedijacije izučavaju se na razini gena. Gen zaslužan za proizvodnju proteina koji razgrađuje onečišćujuću tvar može se izolirati i unijeti u drugi organizam, čime nastaje organizam s poboljšanim bioremedijacijskim svojstvima. Brojna se svjetska istraživanja temelje na genetičkom inženjerstvu na mikroorganizmima, no najveću prepreku upotrebe takvih organizama u bioremedijaciji čine zakonski okviri te nedovoljno poznavanje posljedica njihova oslobađanja u okoliš.
Bioremediation uses the potential of microorganisms for the removal of contaminants from the environment. The metabolic pathways that degrade contaminants into less toxic substances are very complex. Bioremediation mechanisms are studied on the gene level using advanced molecular biology techniques. The gene responsible for the production of a protein that degrades the contaminant can be isolated and introduced into another organism, creating an organism with enhanced bioremediation properties. Scientific research worldwide focuses on genetically engineered microorganisms. However, the greatest obstacle in their application for bioremediation is the legal framework and insufficient knowledge of the consequences of their release into the environment.
As the world’s population and urbanization have significantly increased in the past few decades, the generation of municipal solid waste has accelerated on global scale. The biowaste disposal, which ...is an integral part of municipal waste, leads to leachate production. These kinds of wastewater are characterized by complex composition with very high concentrations of organic and inorganic pollution substances and toxicity, which may have harmful impact on the environment. This study investigated the physico-chemical and biological characterization of leachate from biowaste. The experiments were conducted in batch performance with initial concentration of leachate, expressed as chemical oxygen demand, 12.21 ± 0.46 g O2/L and pH value 4.05 ± 0.13. Obtained results showed that leachate from biowaste have high value of chemical oxygen demand, toxicity and low pH. Overall efficiency of the process of aerobic biodegradation was 89 %. The abundance of viable bacterial cells and development of activated sludge flocs during the experiment confirmed the biodegradability of leachate from biowaste.
U ovom radu provedena je biološka obrada agroindustrijskog otpada (P1), biootpada (P2) i biorazgradljivog komunalnog otpada (P3) procesom kompostiranja u adijabatskom reaktoru tijekom 21 dana. U ...pokusima P1, P2 i P3 postignuta je maksimalna temperatura od 52, 55 i 57 °C, a termofilna faza je trajala 8, 5 i 6 dana. Ukupno je nastalo 122, 407 i 389 g kgHT0–1 CO2 odnosno 89, 148 i 559 mg kgHT0–1 NH3. pH-vrijednost je na početku procesa bila u neutralnom području, a na kraju u blago lužnatom području. Vlažnost supstrata se povećala za oko 5 %, dok se omjer C/N smanjivao uslijed smanjenja udjela organskog C te povećanja udjela N. Shodno navedenom, postignuta je konverzija od 48 %, 71 % odnosno 56 % u pokusima P1, P2 i P3.
The aim of this work was biological treatment of agroindustrial waste (P1), biowaste (P2) and biodegradable municipal solid waste (P3) by the composting process in adiabatic reactor during 21
days. In experiments P1, P2, and P3, a maximum temperature of 52, 55, and 57 °C was reached,
and the thermophilic phase lasted 8, 5, and 6 days. The cumulative evolved CO2 and NH3 was
122, 407, and 389 g kgVM0−1 and 89, 148, and 559 mg kgVM0−1, respectively. The pH value at the
beginning of the process was in the neutral and at the end in the slightly alkaline domain. The
substrate humidity increased by about 5 %, while the C/N ratio decreased due to a decrease in the
organic C content and an increase in N content. Consequently, a conversion of 48 %, 71 %, and
56 %, respectively, was achieved in experiments P1, P2, and P3.
PDF
