The tobacco industry produces large quantities of solid and liquid waste. This waste poses a significant environmental problem, as some major components are harmful and toxic. The aim of this work is to isolate and identify the nicotine-degrading microorganisms in the composting of tobacco waste. The bioremediation process for the detoxification of waste was carried out in a column reactor at an airflow-rate of 0.4 L min−1 kg−1. The concentrations of nicotine and number of CFU in the samples taken from reactor were monitored over nineteen days. After nineteen days, 89.8 % of nicotine conversion was obtained. A nicotine-degrading bacterium, strain FN, was isolated from the composting mass and identified as Pseudomonas aeruginosa on the basis of morphology, 16S rDNA sequence, and the phylogenetic characteristics. To confirm that the isolated Pseudomonas aeruginosa FN is the actual nicotine degrader, batch experiments were performed using tobacco leachate. It was confirmed that the strain FN possesses a considerable capacity to degrade nicotine with simultaneous COD removal. The Monod kinetic model for single substrate was applied to obtain the substrate degradation rate and half saturation constant.

The gaseous byproducts produced during the composting of different kinds of solid waste are carbon dioxide (CO2) and ammonia (NH3). CO2 is a greenhouse gas and NH3 is a toxic and corrosive air pollutant so, they must be removed from exhaust gases prior to release into the atmosphere. The purpose of this work was to investigate the sorption of CO2 and NH3, evolved during composting, on zeolite and potting soil. The composting of the mixture of grape waste (GW) and tobacco waste (TW) in the mass ratio GW: TW = 55: 45 (dry mass basis) was carried out under forced aeration (0.645 L min−1 kg−1) in a column reactor (10 L) under adiabatic conditions over 21 days. Adsorption of the gases evolved was carried out in the fixed-bed column reactor (0.166 L). The most important physical-chemical characteristics of the composting mass and adsorbents and the evolved CO2 and NH3 were closely monitored. The highest CO2 and NH3 concentrations were measured at the thermophilic stage and the cooling stage of composting, respectively. The results showed that zeolite and potting soil were good adsorbents for the sorption of CO2 and NH3. The zeolite adsorbed 31 % of the evolved CO2 and the entire concentration of ammonia, whilst the potting soil adsorbed 3 % of CO2 and 49 % of NH3 from the exhaust gases.

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Composting is a biochemical process converting organic components into stable compost with release of heat, water, CO 2 and NH 3 . The objective of this work was to determine the amount of CO 2 and NH 3 in the exhaust gases during composting of tobacco waste (TW) and mixture of tobacco and grape waste (TGW , respectively.

Several adsorbents, such as natural zeolite clinoptilolite, modified zeolite, grape and olive wastes have been investigated for removal of chromium (VI) ions from aqueous solutions by performing batch kinetic sorption experiments. Natural zeolite, modified zeolite, grape and olive wastes have removed 5 %, 13 %, 73 % and 62 %, respectively, of Cr(VI) ions from aqueous solution. Equilibrium experimental results were fitted to Langmuir and Freundlich isotherms to obtain the characteristic parameters of each model. According to an evaluation using Langmuir equation, the maximum Cr(VI) adsorption capacity of grape waste was 108.12 mg g -1 and of olive waste 100.47 mg g -1 at pH 2. The equilibrium kinetic data were analyzed using pseudo-first-order and pseudo-second-order models, and parameters were estimated by using non-linear regression analysis. Langmuir model and pseudo-second-order model describes better the obtained results than Freundlich model and the pseudo-first-order model. The adsorption of Cr(VI) ions increased with temperature and the negative values of ∆G° for investigated adsorbents confirmed the feasibility and spontaneous nature of the adsorption process.