The reduction of oily sludge and scum with high water content by hot washing and analysis of the main factors that affect the reduction and oil recovery rate of oily sludge and scum in hot washing were investigated. Best process conditions for the reduction of tank bottom sludge, refining sludge, and oily scum were carried out, which can make the oil recovery rate and reduction rate of tank bottom sludge after reduction reach 96.30% and 93.00%, respectively, the oil recovery rate and reduction rate of refining sludge after reduction reach 95.36% and 92.60% respectively, and the oil recovery rate and reduction rate of oily scum after reduction reach 95.92% and 93.60% respectively. After treatment, the oil content of the residue is reduced to below 5.1%, and the water content is reduced to below 59.0%. Oil content in the separated water is lower than 200 mg.L-1, and the water content in the separated oil is lower than 0.2%, far below the requirement of 0.5% in the oilfield’s crude oil gathering and transportation standard.

Hospital waste is a burning issue that severely impacts public health. This study in three big hospitals in Lahan and Rajbiraj, Nepal, for one year (2019 March-2020 February) aims to analyze some parameters that directly help waste management properly. Field study, questionnaire, and interview methods were followed. The average moisture content of wastes of all three hospitals was 55.79%. There was no variance in the three hospitals’ moisture content values of wastes (F = 1.89 P-value = 0.165 F crit = 3.284917651). The average temperature of dumped waste was 23.23°C, and the temperature of all three hospitals was closely associated (F = 0.998, P-value 0.379, Fcrit = 3.28). The average pH value of wastes from the three hospitals was 4.44, and it from all three sites was strongly associated (F = 0.0668, P-value 0.935, Fcrit = 3.284). There was no relation between income and types of waste production (ꭕ2 = 0.8, df = 4, significance level = 0.05), but there was a high association between the level of income and amount of waste production. There was a high association between the nature of hospitals and types and the amount of waste (ꭕ2 = 77.09, df = 4, Significance level = 0.05). In Sagarmatha Choudhary eye hospital Lahan, there was no significant correlation between the number of patients and the amount of waste (Correlation = -0.187889 at 0.05% significance level). Unique Hospital Rajbiraj showed a correlation between the number of patients and the amount of waste (correlation = 0.1183 at 0.05% significance level). In Gajendra Narayan Singh Hospital, there was a correlation between the number of patients and the amount of waste (Correlation = 0.3453, at 0.05% significance level). There was no association between the qualification of respondents and their responsibilities regarding the services provided by hospitals (ꭕ2 = 1.43, df = 6, Significance level = 0.05). It is recommended for better management and installment of modern technologies for waste management.

Globally organic wastes are generated from fruits, vegetables, and their peels. It is mostly decomposed in landfills or by composting methods. Food processing industries, vegetable markets, and restaurants produce a huge amount of organic waste daily, generally disposed of in the environment or composted. Producing an eco-enzyme from organic kitchen waste was an innovative solution for domestic waste pollution. It is an enzyme solution obtained from an organic waste substance that contains organic acids, enzymes, and mineral salts. It is produced by performing a simple batch fermentation that involves a mixture of brown sugar, fruit or vegetable waste, and water in the ratio of 1:3:10. Two types of the eco-enzyme were produced by a fermentation process using vegetable and fruit peels for about 90 days involving Saccharomyces cerevisiae. The ultimate liquid or enzyme obtained was brown. Eco-enzyme 1 from (Cucurbita maxima) contained hydrolytic enzymes like amylase and lipase. The microbial diversity was observed, and bacteria like Yersinia sp., Bacillus sp., and fungi like Trichoderma sp. and Penicillium sp. No enzymes and microorganisms were observed in Eco-enzyme 2 (Citron). Eco-enzyme 1 with 50% dilution effectively reduced various parameters like BOD, COD, TDS, Nitrate, Nitrite, and Ammonium in the effluent. Also, it promoted plant growth within 10 days compared to the control. Therefore, the present study outlines how the eco-enzyme could be used to treat industrial effluent cost-effectively and environmentally friendly.

In the present study, we studied the concentrations and proportions. We identified the potential sources and health risks of 12 probably carcinogenic polycyclic aromatic hydrocarbons (PAHs) in rice grain from 31 sites in Thailand and Myanmar. The findings showed that PAH concentrations in rice grain samples from Thailand and Myanmar were in the range of 0.09 to 37.15 ng.g-1 with an average value of 18.22 ± 11.76 ng.g-1 and 0.07 to 150.73 ng.g-1 with an average value of 34.70 ± 40.57 ng.g-1, respectively. The majority group of PAHs in the rice grain samples from Thailand were the five-ring PAHs (78%), followed by four-rings (12%) and three-ring PAHs (9.5%), respectively, while for Myanmar was the five-ring PAHs were the majority (64.02%), followed by six-rings (15.22%) and four-ring PAHs (13.58%), respectively. The diagnostic ratio analysis suggested that pyrogenic origin is a major source of PAHs, and principal component analysis (PCA) identifies the incomplete combustion of fuel as likely the primary source of emissions source of PAHs contamination in rice grain samples. The total values of incremental lifetime cancer risk (ILCR) of PAH content of rice grain for children and adults were 1.95 × 10-8 and 1.44 × 10-8, respectively, for Thailand and 1.83×10-7 and 1.35×10-7 for Myanmar, which showed that the incremental lifetime cancer risk from rice grain was lower than the baseline set is considered to be safe levels.

The occurrence of heavy metals in soil and selected edible plants (Manihot esculenta, Dioscorea rotundata, Ipomoea batatas, Telfairia occidentalis, and Chromolaena odorata) in the vicinity of major Lead-Zinc mining sites in Ebonyi State, Nigeria was investigated. The concentrations of the detected heavy metals in soil from the study sites ranged from 0.38-77830.99 (mg.kg-1). The limit values for all detected metals in soil from the mining sites were exceeded in most instances. The results showed that the plant species accumulated heavy metals near the mining sites to varying levels in their shoots and roots. The limit values for all detected heavy metals in the edible plants were not exceeded except in a few instances. The plant species demonstrated varying effectiveness for phytoextraction, indicating their appropriateness in the phytoremediation of heavy metal-contaminated soil. Therefore, examining the environmental consequences of uncontrolled mining activity in the vicinity of the mining sites with a scientific approach has helped to increase our knowledge of the pollution problem in the mining sites, reveal the ferocity of the situation, and contribute to the techniques presently in use for monitoring chemical pollution in a mining-impacted ecosystem.

Plastics are the most rapidly growing materials in terms of production and consumption. The durability, inertness, light weight, flexibility, and low cost are the key characteristics that make plastic suitable for application in various fields, including the construction, automotive, electronics, and packaging industries. Due to widespread usage in daily life and many industrial processes and operations, more than 300 million tons of plastic waste are produced globally annually. Indiscriminate use of plastics such as polyethylene causes environmental pollution and impacts human health due to irreversible changes in the ecological cycle. Due to its low biodegradability, polyethylene accumulation has recently emerged as a momentous environmental concern. The conventional methods, such as recycling or disposing of polyethylene, are exorbitant, and incineration results in the emission of toxic chemical compounds. Therefore, the most recent research progressively focused on the biodegradation of polyethylene with the application of bacteria as novel approaches to counteract plastic waste. This review summarizes the type of polyethylene and the environmental issues. It also briefly discussed the genes and enzymes of bacteria involved in the degradation of polyethylene. In addition, it attempts to address factors influencing degradation and techniques used for monitoring degradation.

In most of the research works, similar metal electrodes were used, resulting in high operating costs, and the reuse of the treated water was not explored. The major goal of this research is to lower the cost of the electrocoagulation (EC) process by employing electrodes made of different metals and to investigate whether it is possible to reuse the water that has been treated by doing so. It was done to optimize the operational parameters such as pH, voltage, time, electrolyte, and dye concentrations. The energy and electrode consumption was calculated as 0.29 kWh.m-3 and 3.5×10-2 kg.m-3, respectively. The HPLC and LC-MS studies shows the degradation of dye and the formation of intermediary compounds, which were less toxic. The sludge obtained from the EC process was subjected to EDX and XPS analysis to know the composition of metals and the formation of metal hydroxide coagulants. The phytotoxicity of the treated water after EC was examined using Trigonella foenum-graecum seeds. The results showed an utmost color removal efficiency (CRE%) and COD removal of 99.78% and 92.86% with an operating cost of US$ 0.028, which is comparatively 98.12% lower than the other conventional electrodes. The treated toxicity test of water was comparable to the toxicity test of tap water.

Based on research findings, Bangladesh’s river water, crucial for domestic, agricultural, and industrial use, has long been in a terrible situation. There have been numerous instances of significant contamination in the waterways surrounding Dhaka city, including the Buriganga River, and in Chattogram city, including the Karnaphuli River, over the past 40 years. The existing data demonstrate that other urban rivers, particularly Karatoa, Teesta, Rupsa, Pasur, and Padma, are also in severe condition due to the disposition of huge pollutants. Contaminants flowing with the water have severely polluted the downstream areas of the rivers. High metal concentrations are frequently observed in river water during the dry season. In the Buriganga River and at certain locations in the Turag, Balu, Sitalakhya, and Karnaphuli Rivers, the presence of dissolvable oxygen (DO) is nearly zero. NO3, NO2, and PO4-3 pollution has also occurred in many rivers. Most rivers have Cr, Zn, Fe, Pb, Cu, Cd, Mn, As, and Ni concentrations beyond the legal limit for drinking water. In contrast, some rivers have metal concentrations above the legal irrigation water limit. The majority of the rivers, particularly the peri-urban rivers in Dhaka city, Teesta, Korotoa, Rupsha, Karnaphuli, and Meghna Rivers, have significantly higher metal concentrations, according to sediment data. Metal concentrations in sediment are generally higher than USEPA standards in most rivers. Metal concentrations in fish and crops demonstrate metal bioaccumulation. The trend in metal concentration follows the order of water, fish, and sediment. It has been shown that crops irrigated with tainted water contain dangerous metals. The analysis of daily intake data on carcinogenic and noncarcinogenic substances reveals that consuming contaminated food can seriously impact human health.

Achanakmar Tiger Reserve (ATR), endowed with rich biological diversity and lush green vegetation in and around, makes it more unique. It is also an integral part of the Achanakmar Amarkantak Biosphere Reserve (AABR) and has been identified as one of the important tiger reserves of the Central Indian landscape due to its connectivity with other protected areas and tiger reserves in neighboring landscapes. Vegetation mapping and monitoring are important to understand changes in ecosystem processes and associated temporal and spatial impacts. Pre- and post-monsoon IRS, LISS III, and AWiFS satellite data from 2000, 2004, 2008, 2010, and 2013 were used for the present study. This paper is an attempt to examine the variation in the normalized difference vegetation index (NDVI) of ATR and its buffer zone on a seasonal and temporal basis. Climate conditions such as temperature, precipitation, relative humidity, etc. play an important role in the growth and development of healthy vegetation. The NDVI value of ATR has shown fluctuation and recorded positive growth over the past 14 years with few exceptions. The post-monsoon season recorded a higher NDVI value as compared to the pre-monsoon months. The maximum NDVI value was recorded in 2004 (+0.539) for the entire ATR and its buffer zone.

An endeavor has been made to understand the hydrogeochemical characteristics of groundwater from shallow aquifers of the PG1 watershed (latitudes 19°38’30” to 19°50’30” N and longitudes 79°04’00” to 79°11’00” E). The appropriateness of groundwater has also been checked for various purposes. The groundwater from the study area is alkaline and slightly saline. The Ca2+ ˃ Mg2+ ˃ Na+ ˃ K+ and HCO3- ˃ SO42- ˃ Cl- ˃ NO3- was the ascendancy of cations and anions. The earth metals (Ca + Mg) exceeded the alkali metals (Na + K). The positive correlation interpreted from the interrelationship of Na+ vs Cl- exhibited a silicate weathering process for the liberation of ions in groundwater at the rock-water interface. In addition to the non-lithological source, anthropogenic inputs were inferred, indicating the agricultural fertilizers and domestic wastewater. All the groundwater samples from the study area are suitable for drinking and domestic use. The groundwater from the study area is also suitable for irrigation with negligible exceptions.