SORPTION OF METHYLENE BLUE ONTO ORANGE AND LEMON PEEL

This study examines the sorption of methylene blue on the cheap unconventional bio sorbents, citrus fruits: oranges and lemons. Bio sorbents which was used was: orange and lemon peel, seeds and pulp. The results are compared with results of sorption to mineral sorbents, zeolite clinoptilolite, Pyrolox and Birm. Sorption kinetics and the influence of pH on the sorption of methylene blue on orange and lemon peel was examined. Sorption isotherm of methylene blue onto the orange end lemon peel was determined at 25oC with the initial concentrations of methylene blue 50 – 1000 mg/dm3. The sorption kinetic data were analyzed using pseudo–first–order and pseudo–second-order models. It was found that the pseudo-second-order kinetic model was the best applicable model to describe the sorption kinetics. When the pH of the solution dyes was 2-3, the sorption of methylene blue was slightly weaker than at pH 3-6. In the studied concentration range 50-1000 mg/dm3 sorption of methylene blue on orange and lemon peel was linear, with sorption efficiency of approximately 100%. The capacity of zeolite for methylene blue was 20 mg/g. Sorption capacity of citrus waste was significantly higher than in the mineral sorbents (zeolite, Pyrolox, Birm)

KINETICS OF AEROBIC TREATMENT OF TWO-PHASE OLIVE-MILL WASTE BY ACTIVED SLUDGE IN SEQUENCING BATCH REACTOR

Olive mill waste has a very high organic load, high amount of toxicity/phytotoxicity-associated compounds, low pH value and high electrical conductivity. In this study, the removal of COD (chemical oxygen demand) and total phenols from extracted wastewater (EW) from two-phase olive-mill waste (TPOMW) in sequencing batch reactor (SBR) was studied. The experiments were carried out at 23 °C with the initial COD concentration of 5 g L-1 and 10 g L-1 at different initial concentrations of activated sludge (3 and 6 g L-1). The obtained results showed that activated sludge possessed a strong ability to degraded organic matter and total phenols. The COD and phenols removal efficiency was between 80 - 90 %. Toxicity Impact Index (TII50) was 312.5 which indicated that this wastewater is extremely toxic. Four different kinetic models were select to describe the kinetics of TPOMW biodegradation. The lowest deviation and the best fit with experimental data were achieved using Endo-Haldane model

Emisija plinova tijekom kompostiranja čvrstog otpada

Composting is a biochemical process converting organic components into stable compost with release of heat, water, CO2 and NH3. The objective of this work was to determine the amount of CO2 and NH3 in the exhaust gases during composting of tobacco waste (TW) and mixture of tobacco and grape waste (TGW). The cumulative evolved CO2 during 21 days of composting of TW and TGW, per mass of volatile matter, was 94.01 g kg–1 and 208.18 g kg–1, respectively, and cumulative evolved NH3 during composting of TW and TGW, per mass of volatile matter, was 504.81 mg kg–1 and 122.45 mg kg–1, respectively. This work is licensed under a Creative Commons Attribution 4.0 International License.Kompostiranje je proces biorazgradnje organske tvari u stabilan produkt – kompost, pri čemu se oslobađa toplina, voda, CO2 i NH3. Svrha ovog rada bila je odrediti količinu nastalih izlaznih plinova, CO2 i NH3, tijekom kompostiranja duhanskog otpada i mješavine otpada duhana i grožđa. Tijekom 21 dana kompostiranja duhanskog te miješanog duhanskog i grožđanog otpada, prema ukupnim hlapljivim tvarima, nastalo je 94,01 g kg–1 i 208,18 g kg–1 ugljikova dioksida, odnosno 504,81 mg kg–1 i 122,45 mg kg–1 amonijaka. Ovo djelo je dano na korištenje pod licencom Creative Commons Imenovanje 4.0 međunarodna