Volume 22 - 2020

Isotope mass balance in lake systems is strongly correlated with several climatic factors such as temperature, evaporation, precipitation and air moisture. On the other hand, the sedimentary budget of lake basins driven by climate, tectonic and/or human impact is an essential pool of environmental records. Precipitation, springs and lake water δD and δ18O isotope data were used in order to understand the key factors for the hydrological balance of Balkan lakes in West Macedonia. In general, it is concluded that the open lake Ohrida and the semi-closed lake Kastoria are more buffered hydrological as karst systems and less sensitive to evaporation effect, in contrast to the closed lake system of Prespes that present a strong dependence on climate seasonality. Based on oxygen isotopes in bulk sediments, it is concluded that in Kastoria lake basin an increased run-off on the land surface, probably under a more humid period, in 2.4 kyr BP disturbed the transition to a drier regime from mid/late Holocene to present.

Ammonia (NH3) and hydrogen sulfide (H2S), as the main odorous substances in waste gas from livestock farm, have attracted more attentions rescently since their adverse effects. To remove NH3 and H2S efficiently, high-pressure hydrothermal modification (HPHM), metal salt solution impregnation modification (MSIM), and HPHM combined with MSIM are used to modify the activated carbon (AC). Meanwhile, the pore structure and surface functional groups of AC and MAC absorbents are characterized by BET, FTIR and Boehm titration method. The adsorption performance of activated carbon (AC) and modified activated carbon (MAC) are compared. The effects of modification and operation conditions on the adsorption performance of MAC for NH3 and H2S are studied in detail. It was found that the optimal adsorption performance of MAC can be achieved by high-pressure hydrothermal modification (HPHM) followed by the metal salt solution impregnation modification (MSIM). With gas space velocity of 900 h-1 and total inlet concentration of 550-650 mg m-3 at 50 oC, the adsorption capacities of NH3 and H2S of GS270CuCl6010 are 24.17 mg g-1 and 26.20 mg g-1, respectively. The adsorption of NH3 and H2S by MAC is the result of both physical adsorption and chemical adsorption.

Volatile Organic Compounds (VOCs) are toxic for the environment and human health and their tendency to readily volatilize in the atmosphere can lead to problems connected to odours annoyance. Conventional VOCs gaseous emissions treatments entail the application of chemical-physical processes, only promoting the transfer of the contaminants from gas to liquid and/or solid phases. Advanced Oxidation Process (AOPs) and biological processes, conversely, support the oxidation of the organic pollutants, promoting their conversion into harmless and odourless compounds. The integration of booth processes is suggested to increase treatability of VOC. The research presents the application of an innovative treatment system composed by an AOPs pretreatment coupled with a bio-scrubbing unit for the abatement of VOCs, with the aim to increase the removal efficiency. The evaluation of the performance of the proposed system is discussed with reference to the analysis carried out using toluene as model substance. Different operating conditions have been analyzed and investigated to optimize the removal efficiency. The results show that the ozonation applied as pretreatment to the biological process may promote an increase of the pollutant biodegradability along with synergic effects due to the absorption of the ozone derived compounds into the culture growth, resulting in a significant enhancement of removal performances respect to the conventional biotechnologies. A toluene removal efficiency up to 95% were obtained under the investigated conditions.

In the recent era, utmost attention is paid towards exploring the alternative source of energies, being more specific green energies. In modern days, when growing energy scarcity is a hot topic and considered as a global threat, in that context a green technology capable of sustainably addressing waste management issues and synthesize waste-derived end-product such bio-diesel from Jatropha Curcas linnaeus (JCL) and Chlorella vulgaris shall be paid ancillary attention. The attribution of the above-mentioned species and Lemnagibba L towards the purification of the municipal solid waste (MSW) leachate by utilizing its bioaccumulation properties and ultimately yielding several value-added co-products could be the solution of the era in terms of sustainable leachate treatment. A specially designed ridge furrow phytoremediation wetland was fabricated under the controlled environment associated with a pre-treatment facility and bottom lining system to captivate the downward percolation. A 1.5 m high Jatropha species were planted at an interval of 1 m on the ridges and the root for the same found to reach a depth of 0.8 m on an average over a period of 3 months. Leachate was supplied by means of free flow into the furrows with an initial addition rate of 1 m3 per day for a 10 m x 10 m remediation hybrid pond system and simultaneously the loading was elevated up to 80 m3/ha/day. Prior to the active remediation zone, a pre-treatment unit was installed which works on the bio-accumulation property of the vetiver grass (Chrysopogon zizanioides). A packed bed system of gravel, marble chips, sand, and coconut coir as a medium of filtration was installed to bring the concentrate waste juice up to the wetland treatment standard. Moreover, the bleaching influence of the sunlight also found to be effective against pathogen removal, active evaporation, and evapotranspiration. The ultimate treatment capacity for the designated size was assessed as ~ 0.03 m3 per day ascertained with an HRT value of 45 days. The ultimate outcome was on par with the influent characteristics obligatory for the tertiary units with a comprehensive efficacy value evaluated as approx. 60%. Thus, it’s quite evident to claim the feasibility of the present study towards the bio-remediation of the enormous quantity of leachate generation associated with the handling of solid waste which is otherwise, a costly affair.