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The remarkable properties of polysulfone (PSF) membranes have contributed to their use in many ultrafiltration applications. Meanwhile, this huge usage of PSF films and its short service life have generated a huge amount of waste PSF films that need to be managed carefully. Within this framework, this is the first research specifically developed to valorize the end-of-life of PSF membranes and convert them into high-value chemical and energy products using pyrolysis treatment. The treatment was performed using a thermogravimetric analyzer (TGA), while the structure and abundance of the phenol and benzoic acid compounds in the generated vapor were determined using Fourier-transform infrared (FTIR) spectroscopy and Gas chromatography-mass spectrometry (GC-MS). Thermogravimetric recorded data at different conditions (5–30°C/min) was subjected to linear and nonlinear models including KAS, FWO, Friedman, Vyazovkin, and Cai to assess the pyrolytic kinetic behavior of PSF films. The films showed higher content of volatile matter (57%), lower NOx emissions (0.321%), and a little bit more SOX emission (6.909%). The GC-MS showed that the pyrolytic gaseous products are rich in phenol (24.3%) and benzoic acid (52.4%) compounds and the highest abundance was achieved at 30°C/min. Whereas activation energies were estimated in the range of 193–240 kJ/mol based on linear kinetic criteria versus 161–163 kJ/mol in the case of nonlinear models, where R2 values (>0.91) indicated perfection. Also, distributed activation energy and independent parallel reaction kinetic models showed a good fit with the TGA-DTG experimental data with the minimum deviation. The study confirmed the potential of pyrolysis treatment in converting wasted PSF films into a new source for the recovery of phenolic and benzoic acid.

Olive mill wastewater (OMWW) management is recognized as the major defy that olive oil industry is facing. Recently, we have established an eco-friendly strategy for the OMWW conversion into irrigation water sources, green biofuels and biofertilizers. This work is a part of a series of papers detailing the different steps established in this environmental friendly strategy for OMWW management. It deals with the bio-oil production and characterization during the pyrolysis of OMWW impregnated on olive pomace (OP) in a pyrolyzer pilot. Results show a bio-oil production yield of 36 wt% during the pyrolysis test. This yield could be attributed to the recovery of organic compounds from OMWW through OP impregnation and their conversion to bio-oil. The bio-oil properties show that viscosity and flash point values could reach the European standards. However, the lower heating values (26 MJ/kg) and the acidic character limit its direct use. These values are attributed to the higher water and oxygen contents. The GC/MS analysis confirms these properties showing the presence of phenolic molecules and long chain organic acids. Therefore, OMWW impregnation on OP and pyrolysis could be considered as a promising issue for bio-oil production. However, this bio-oil requires an upgrading step for a better valorization.

The quantities of sewage sludge generated in the treatment plants already pose serious problems related to its storage and use. The Article 14 of the Urban Waste Water Treatment Directive 91/271/EEC specifies, “Sewage sludge from waste water treatment shall be re-used whenever appropriate. Disposal routes shall minimize the adverse effects on the environment “. Therefore, priority is given to the reuse of sewage sludge, rather than disposal it to landfills or storage plants. The analysis of scientific literature related to the quantities of sewage sludge and its chemical composition, possibilities of its use in thermal process and possibilities of residual product use in other areas as a raw material was carried out by the author of dissertation. Sewage sludge samples were collected from the major water treatment systems in Lithuania during the preparation of dissertation. After investigation of their chemical quality, author selected sewage sludge samples from a small city (Šilutė) for a more detailed research. Author designed and constructed a pyrolysis stand where he carried out thermal decomposition (pyrolysis) of sewage sludge. Solid fraction as char obtained from sewage sludge was used in experimental research on cultivation of fibre hemp (Canabis sativa L.). In order to assess the regularities of distribution of heavy metals, alkaline earth metals and alkaline metals as well as of non-metals the author carried out chemical analysis of sewage sludge, sludge pyrolysis products and gifferent parts of fibre hemp (roots, stem, leaves). According to the results author found distribution of elemental migration in the course of the application of the principle of sustainable use of sewage sludge., Vandenvalos sistemose susidarančio dumblo kiekis jau dabar kelia rimtų problemų, susijusių su jo saugojimu ir panaudojimu. Miesto nuotekų valymo direktyvos 91/271/EEB 14 straipsnyje nurodoma, kad „dumblas, susidaręs valant nutekamuosius vandenis, jei tik įmanoma, turi būti panaudojamas. Jo šalinimo būdai privalo iki minimumo sumažinti aplinkai daromą neigiamą poveikį“. Todėl pirmumas teikiamas nuotekų dumblo antriniam panaudojimui, o ne išvežimui į sąvartynus ar saugojimo aikšteles. Mokslinių tyrimų rezultatai rodo, kad pirolizė yra pagrindinė alternatyva nuotekų dumblo antriniam panaudojimui. Autorius atliko mokslinės literatūros analizę, susijusią su susidarančiais nuotekų dumblo kiekiais ir jo chemine sudėtimi, dumblo panaudojimo energijos gamybai bei susidarančių produktų antrinio panaudojimo galimybėmis. Rengiant disertaciją, iš didžiausių Lietuvos vandenvalos sistemų buvo surinkti nuotekų dumblo mėginiai. Įvertinus jų kokybę pasirinkti nedidelio miesto (Šilutės) nuotekų dumblo mėginiai tolimesniems tyrimams. Autorius suprojektavo ir pagamino pirolizės stendą, kuriame buvo atliekamas nuotekų dumblo terminis (pirolizė) skaidymas. Eksperimentiniuose pluoštinių kanapių (Canabis sativa L.) auginimo tyrimuose autorius panaudojo nuotekų dumblo anglį gautą po pirolizės proceso. Siekiant įvertinti sunkiųjų metalų, šarminių metalų ir šarminių žemių metalų bei nemetalų pasiskirstymą, autorius atliko cheminę nuotekų dumblo, dumblo pirolizės produktų, atskirų pluoštinės kanapės dalių (šaknų, stiebo, lapų) analizę. Pagal gautus eksperimento rezultatus buvo nustatyti elementų pasiskirstymo dėsningumai vykdant darnaus nuotekų dumblo panaudojimo principą.

Susidarantys nuotekų dumblo kiekiai ateityje didės, kadangi šalyje panaudojant ES paramą plėtojamas vandentiekio ir nuotekų surinkimo tinklas. Nuotekų dumblas yra neišvengiamas nuotekų valymo proceso produktas, kuriame yra labai daug kenksmingų medţiagų. Dumblo perdirbimo ir panaudojimo galimybės Europoje pastaruoju metu intensyviau plėtojamos. Naujausios nuotekų dumblo panaudojimo galimybės, turinčios labai didelį mokslininkų susidomėjimą yra šios: deginimas (išgaunant energiją), drėgnas oksidavimas, pirolizė, dujinimas, deginimas kartu su kuru, kuris yra naudojamas energijai išgauti (pvz. biokuras). Darbo metu nagrinėtos dvi dumblo panaudojimo galimybės energetikoje: dumblas, kaip trąša energetinių ţeldinių plantacijose ir dumblo dujinimas maišant su medienos biomase. Pirmoje darbo dalyje atliktas prieš 19 metų pasodintos energetinių ţeldinių plantacijos tyrimas. Tyrimo metu nustatytas medienos masės prieaugis ir sunkiųjų metalų pasisavinimas. Antroje darbo dalyje nustatyti dumblo ir jo mišinių su medienos biomase pagrindiniai kuro parametrai: drėgmė, šilumingumas, CHNS-O kiekiai, peleningumas, sunkieji metalai. Atlikta termogravimetrinė dumblo ir jo mišinių su medienos biomase analizė pagal pasirinktus dujinimo parametrus, kai pastoviai keliama temperatūrą 20 ˚C /min iki 995˚C, o oro padavimas yra 5 %, 10 % ir 17,5 %. The amount of formed sewage sludge will be on the increase because of development of plumbing and wastewater accumulation network when using EU support in the country. Sewage sludge is inevitable product of the process when cleaning the wasterwater, there are a lot of harmful materials in it. The opportunities to reprocess and use sewage sludge in Europe are increasing more intensively recently. Scientists are interested in those newest opportunities to use sewage sludge: combustion (extracting energy), wet oxidation, pyrolisis, gasification, combustion with fuel, which is used to obtain energy (e. g. biofuels). During the work there were pending two opportunities how to resort sewage sludge in energetics: sewage sludge as a fertiliser in energetic plantations and the gasification of sewage sludge mixing it with biomass of wood. There was done the analysis of the 19 years old plantation of power afforests in the first part of work. During the analysis the increase of wood-pulp and the assimilation of hevy metals were found. During the second part of work there were established the main fuel parameters of sewage sludge and its compounds with wood-pulp: moisture, calorific value, amounts of CHNS-O, ash-content, heavy metals. Thermogravimetric analysis of sewage sludge and its compounds with wood-pulp was done by the selected gasification parameters, when the temperature is constantly raising to 995 ˚C every 20 ˚C /min, and the innings of air is 5 %, 10 % and 17,5 %.