No abstract

Most of developing countries are facing environmental degradation challenges as these countries use energy from fossil fuels to enhance economic activities and that leads to environmental degradation. The use of renewable energy is required to mitigate environmental degradation; however, developing countries may not yet have reached the desired level to acquire renewable energy. It is important for developing countries to make polices to shift from nonrenewable energy to renewable energy use to protect environmental quality. In this regard, the importance of different energy sources and financial development in enhancing environmental quality in 21 developing countries is examined from 1970 to 2018. The study employed dynamic estimator, and the results indicate that the sources of renewable energy enhance environmental quality as compared to nonrenewable energy and its sources. Financial development also lowers environmental quality in our results. The study recommends reducing carbon emissions by reducing the use of fossil fuel energy and acquiring new technologies, attracting foreign investors in clean energy that provide clean technologies for green production, and investing in renewable energy sources to evade nonrenewable energy. Policy makers should adopt environmentally-friendly strategies and equipment to protect environmental quality, while striving for achieving economic growth.

Wastewater from tapioca processing factory containing high COD (11,077-19,083 mg/l), SS (4,180-7,600 mg/l) and low pH (4.33-5.60) still causes heavy pollution to receiving water in South Vietnam. Closing the water circuit in the tapioca industries represents a very attractive option for eliminating pollution problems and the reuse of treated wastewater and solid wastes. The investigated and presently occasionally already implemented system consists of primary sedimentation tank, anaerobic treatment using UASB-reactors, aeration tanks using attached growth reactor and oxidation ponds system. Under laboratory conditions, organic loading rates applied in UASB-reactors are up to 40,35 kg COD/m3.d with treatment efficiency of 90-95%, reducing the COD concentration from up to 13,449 mg/l to 624-780 mg/l. The final effluent COD (sol.) after treatment in the pond system operated at hydraulic retention time of 12-20 days is lower than 10 mg/l. This effluent is suited very well either for use in agriculture or in the factory.

Studies on the role of renewable energy consumption and other environmental factors in carbon emission have got considerable attention recently, and they are predicted to get exaggerated in the coming decades. Energy usage increases economic growth and development of a country and backs to global warming and carbon emission which affect the local environment. For the prosperity of a country, it is felt crucial to measure the unavoidable impacts which effect environmental quality. Consequently, the current study investigates the interrelationship of renewable energy consumption, carbon dioxide emission, foreign direct investment, and economic growth in 190 countries of the world for the period of 1980 to 2018. By employing both static and dynamic models, the findings indicate that carbon emission, renewable energy consumption, foreign direct investment, and economic growth affect each other significantly whereas renewable energy consumption has been found beneficial for environmental quality; however, it decreases the inflow of FDI. RE has a decreasing impact, while FDI and carbon emission promote economic growth. The study suggests the promotion of renewable energy resources and policies related to FDI to promote the quality of the environment and achieve economic growth as well.

Expanding the capability of technological innovations is curial in acquiring renewable energy sources, enhancing the efficiency of energy and lowering carbon dioxide emissions which can leads to environmental sustainability however the factors effecting the level of technological innovations needs to be explored. Consequently, this study explores the effect of carbon dioxide emission, energy consumption and foreign direct investment on technological innovations in 179 global countries from 1980 to 2019.  The results indicate that foreign direct investment significantly and negatively affect technological innovations proxy by patent nonresidents in the lower quantiles while this effect is negative insignificant at the highest. Carbon dioxide emission and financial development significantly and positively effect technological innovations proxy by patent nonresidents while energy consumption and trade significantly decrease technological innovations. In case of dependent variable research and development, the effect of foreign direct investment on technological innovations and international trade is negative while financial development and energy consumption positively and significantly affect technological innovations proxy by research and development. The effect of financial development is negative significant and negative insignificant across quantile while the highest quantile gives positive coefficient thus shows that its increase technological innovations proxy by research and development. The findings have considerable policy implications for the sample countries regarding economic growth, foreign direct investment inflow, energy consumption and technological innovations.