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Constructed wetlands with a land-intensive, low energy and less operational requirement have been used as a sustainable green technology for treating wastewaters. But are constructed wetlands sustainable? The objectives of the present study are to evaluate one year monitored horizontal subsurface flow constructed wetland’s treatment efficiency from May 2017 to May 2018 and to estimate the greenhouse gas emissions (GHG) in terms of N2O and CH4. As field data show the average removal efficiencies are low but are all within the effluent standard for water quality. One year average of high suspended solids (91.1 %), high total nitrogen (%85.6), low total phosphorous (22.4% TP), low organic matter (43.1% BOD5 & 35.9% COD) removals are obtained. One year average methane and nitrous oxide emissions at the outlet of constructed wetland are calculated as 17.52 and 0.29 kg/d, respectively.

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.

Two hydrological climate modelling techniques, general circulation model (GCM) and hypothetical climate change scenarios, were used to analyse the hydrological response to the anticipated climate change scenarios in the Subarnarekha river basin in Eastern India. Both models verified individually for the same river basin and a comparative performance of the models was evaluated to relate the two models for the near (2014-2040) period climate. The hydrological response under the anticipated climate change in the Subarnarekha river basin is well assessed by GCM under the RCP 8.5 scenarios compared to the RCPs 4.5. Results indicate GCM best suited over the hypothetical climate change scenarios as GCM has demonstrated their potential in accurately reproducing the past observed climatic changes. The strong performance of the hypothetical climate change scenarios model, particularly for warming climate scenarios, suggests that it may have distinct advantages for the analysis of water balance components in the river basin. The monthly streamflows of Subarnarekha river basin was simulated using a total of 14 years (2000-2013) daily observed streamflow data in the ArcSWAT model integrated with model calibration and uncertainty analysis by means of SUFI-2 algorithm. The results indicate during the calibration the coefficient of determination (R2) and Nash-Sutcliff Efficiency (NSE) were reported as 0.98 and 0.97, respectively, while during the validation the R2 and NSE were obtained as 0.94 and 0.94, respectively, confirms the hydrological model performance was very good both in calibration and validation. The obtained climate change water impact index (ICCWI) values reveal the Subarnarekha river basin is more responsive to climate change. The reduction in precipitation along with the significant warming under the projected future climate is likely to reduce availability of water substantially in the study region. This work would be useful for the effective management of water resources for sustainable agriculture and in mitigating natural hazards such as droughts and floods in the study region.

The problem of air pollution is one of the most important problems faced by the world in the context of large urban agglomerations. Numerous activities are being undertaken all over the world to both counteract existing pollution and prevent the emergence of another one. Manufacturing is one of the activities that have a significant negative impact on the natural environment. Starting from the production itself, through the life of vehicles, and ending with the problems of storage and recycling of used means of transport, at every stage there are negative effects on the environment. There is no doubt that in all types of pro-ecological activities, it may be extremely important to predict the future state based on various determinants occurring in the analysed or preceding period of time. To this end, various types of mathematical and statistical tools are being used. Recently, you can also notice interest in all types of methods aided by artificial intelligence. Such methods include artificial neural networks, fuzzy logic, or evolutionary algorithms. The article presents the problems of environmental pollution as a result of the development of motorization. The main components of exhaust gases from car engines are discussed, which are particularly harmful to the natural environment. Methods for reducing the emission of pollutants emitted from internal combustion engines are described, and the monitoring of hazards related to air pollution is discussed. The possibilities of using artificial neural networks as a tool for modelling the state of air pollution have also been discussed.