Nitrate nitrogen (N-NO3-), the most common pollutant in groundwater, is a result of the effect of diffuse sources of pollution like agriculture and animal husbandry intensive. The land use for these economic activities is very common in the Los Ríos sub-region in the state of Tabasco, Mexico, where the Los Ríos and Boca del Cerro aquifers are located. The aim of this research was to assess the concentrations of nitrate-nitrogen (N-NO3-) in groundwater, determine the quality in agreement with the maximum permissible limits established by national and international regulations, and the risks to the public health and aquatic life. The spatial distribution of N-NO3- was determined using the inverse distance weighted (IDW) interpolation technique. The average nitrate-nitrogen concentration was 0.76 mg.L-1, while the maximum concentration observed was 3.98 mg.L1. This does not exceed the maximum permissible limit (MPL) established in the national and international normativity for drinking water. However, in 50% of the sampling sites, the concentrations of N-NO3- exceed the MPL established in Mexico for the protection of the life of seawater. Relatively low concentrations of N-NO3- have shown to be toxic to certain aquatic organisms, and the aquifers studied discharge a third of the water to the rivers in the area, which flow into the Laguna de Términos Campeche and the Gulf of Mexico. Laguna de Términos Campeche is one of the most diverse and rich environmental systems on earth, where numerous ecosystems converge such as coastal lagoons, wetlands, mangroves, seagrasses, and coral reefs.

Groundwater is essential to the sustainability of India’s environment, economy, and living conditions because it isn’t just the primary source of domestic supply of water in rural areas, but it is also the major and most productive origin of the water. The increased demand for groundwater as a result of reduced rainfall has put a strain on groundwater resources in areas where groundwater is the primary supply of water. The main aim of this study is to identify and explore the groundwater potential zones in Talupula Mandal of 280.3 km2 in Ananthapur district in Andhra Pradesh, India with semi-arid climatic conditions. Based on the field survey approach, groundwater availability is found out in the villages. Schlumberger Vertical Electrical Sounding (VES) survey technique was used to discover the resistivity and thickness of the unmistakable layers. It was carried out in 18 randomly selected sites where groundwater plays an important role in agricultural and domestic use. The thickness and resistivity of first- and second-layer crack sites of the various layers were separated from ground data using IPI2WIN programming. Using software, graphs were plotted and groundwater potential zones were identified for recharging the groundwater. Based on the results, different models of recharge structures for the study area are identified and recommended. Hence the management of groundwater paves the way for sustainable groundwater levels.

Halophytes are unique in that they can thrive in a wide range of soil conditions, from normal to extremely saline. This has recently prompted researchers to consider using halophytes as a phytoremediation end-product as a source for biogas generation. Therefore, applying the anaerobic digestion process for halophytes may have the potential advantage in terms of efficient land utilization, soil remediation, and biogas production. Based on this, the anaerobic digestion efficiency of high saline biomass was investigated in continuous laboratory-scale anaerobic reactors at two different sludge residence times (SRT) of 40 and 80 days. Under mesophilic atmosphere, two reactors were operated, one reactor used organic substrate with 30 g-Na+.L-1 originating from sodium chloride whereas the other was operated with the presence of sodium bicarbonate and sodium sulfate. The salt-tolerant microorganism was gradually developed and the salt concentrations were selected based on the elemental analyses results of 30 species of wild halophyte plants taken from the saline-affected area of the Aral Sea in Uzbekistan during the early phase of the operation. For 40 and 80 days of SRT, respectively, 65.56 percent and 60.42 percent of the feed COD were converted into methane gas by the chloride system. However, only about 60% of the feed COD was converted into methane for bicarbonate, and the remaining fraction of gas was assigned to sulfide as a final product of increased sulfate reduction bacteria activity. These findings showed that the salt-tolerant microorganism could be incubated and the anaerobic digestion process could be adapted for a high-saline substrate, implying that the biodegradability of phytoremediation end-products may be used for methane production.

This research aims to assess the greenhouse gas (GHG) emissions reductions due to the use of biogas technology in Quang Tri Province. With a total of over 354,000 cattle in Quang Tri Province, Vietnam, waste from livestock becomes large. The GHG emitted from the livestock industry is not small, affecting the environment. Currently, there is little concern or documentation about the reduction of GHG emissions in small farms using biogas digesters in central Vietnam. This province has applied technological solutions, typically biogas digesters, but the amount of biogas production is not calculated accurately. Our survey was conducted in Vinh Linh District and Cam Lo District in March 2019 and involved 50 farms equipped with biogas digesters and 20 farms without it. The respondents were selected based on the information provided by local authorities, satisfying two conditions: livestock households and biogas users. The former group was asked 25 questions and the latter was asked 10 questions needed to calculate GHG emissions such as the number of animals and petroleum gas/ firewood consumption. This study uses formulas described in the 2006 guideline issued by IPCC to estimate reduced GHG emissions. The results showed that the average biogas production is 5.52 m³.household-1.day-1. Only 2% of the farms made the best use of the biogas digester. The surveyed households have not really used the most optimal amount of biogas production. In this scenario, this study recommends some solutions for solving the problem. In addition, the average annual emissions before having a biogas digester are estimated to be 20.53 tons CO2e/household/year. After using the biogas, the GHG emissions are reduced to 4.52 tCO2e.household-1.day-1. Thus, the replacement of daily cooking energies with biogas helps reduce 16.01 tCO2e of greenhouse gas for each farm per year.

The world needs to increase renewable and alternative fuel sources such as Biomass, Bioethanol, and Biodiesel to compete with fossil fuels. Biodiesel is an important renewable fuel source since it can be used in regular diesel vehicles without requiring engine modifications. Conventional biodiesel production takes around 90 min of reaction time. A longer reaction time is not suitable for commercial production. Furthermore, traditional products such as oil react with biodiesel methoxide to produce a maximum of 90% biodiesel yield. As the catalyst is not involved with the reaction, pure methanol and methoxide (methanol with KOH catalyst) are separately added to the system to enhance the pre-reaction step. By changing the methanol to methoxide ratio, biodiesel is produced, and yield is calculated. The highest yield, which is 95%, is obtained with a 5:15% methanol to methoxide ratio. The total reaction time with the new experimental procedure is only 20 min. That is a significant reduction by saving operating costs such as energy consumption. Produced biodiesel show similar properties to that of standard biodiesel.

The “Regional Circular and Ecological Sphere” takes advantage of the SDGs’ concept of integrated solutions to numerous concerns, complementing and supporting resources based on the region’s features while maximizing the utilization of local resources. This research makes a comprehensive evaluation of the three aspects of the environment, economy, and society. First, formulate the evaluation indicators of the regional circulation symbiosis zone. Then, choose the cutting conditions of trees according to geographical factors, use the thinning forecasting system and forest GIS data to evaluate the supply potential of thinned wood in the area, and calculate the heat and power generation of wood biomass. According to the above analysis and calculation, 12,000 tons of unused wood chips can be supplied per year for 36 years from 2016 to 2051. From the economic point of view, the purchase of wood chips of 146 million yen due to the local circulation of wood fuel is expected to save about 50 million yen in intermediate input. And it is estimated that if 12,000 tons of unused wood chips can be supplied in the city per year, and about 98.4 million yen can be saved annually. Finally, from a social perspective point of view, biomass power generation of unused thinned timber using materials worth about 146 million yen is expected to create about 20 jobs.

An investigation into the pollution of stormwater runoff from automobile workshops in Nigeria was performed. Also, multivariate regression was used to predict the pH, oil, and grease (O&G) as well as the electrical conductivity (EC) in relation to the characteristics of the solids and metals pollutants of the untreated automobile workshop stormwater. The results indicated that automobile workshops contributed notable amounts of pollutants to stormwater runoff. Results were compared with Nigerian and USEPA standards. It was found that most of the parameters had mean value ranges far greater than standard limits. The multivariate regression showed variations in the results obtained from different automobile workshops. These variations could be due to the influence of factors such as the volume of automobile servicing activities and the waste generated from these activities that flow in the stormwater runoff. However, the bulk of the EC and pH of the stormwater were associated with the concentrations of the total dissolved solids and copper while the bulk of the O&G concentration was associated with the concentrations of lead and cadmium. It is recommended to treat automobile workshop stormwater to prevent detrimental effects in aquatic systems. Future research is aimed at modeling such treatment using multivariate regression techniques is warranted.

Salicylaldehyde (SA) is used in numerous biological, pharmaceutical, and industrial applications. Releasing effluents from these industries contaminates water. So the degradation of salicylaldehyde is necessitated. The electrochemical degradation of salicylaldehyde in buffered media was studied using the eco-friendly cyclic voltammetry (CV) technique on a platinum electrode at different scan rates. Kinetic and electrochemical parameters were evaluated for the reaction such as standard heterogeneous rate constant (k0,2.468×103 s-1 ), anodic electron transfer rate constant (kox,2.507×103 s-1), electron transfer coefficient of reaction (α,0.673), and formal potential (E0, 1.0937) under the influence of scan rate. The nature of the reaction is found to be diffusion controlled. The concentration study in the range of1 mM to 4 mM was calibrated. The limit of detection and the limit of quantification were calculated to be 0.0031 mM and 0.0103 mM respectively.

A preliminary assessment was carried out in identifying the salinity zones due to considerable concern over salty groundwater resources in Vanuatu’s Shefa and Malampa regions. Electrical conductivity (EC) and pH were measured on the islands of Efate, Lamen, and Nguna in Shefa province, as well as the islands of Ambrym and Paama in Malampa province. Thirty-four percent of the samples exceeded Vanuatu’s National Drinking Water Standards with an average of 3123 μS/Cm indicating possible salinity zones. Whereas the average pH of 7.21 was in the range of acceptable levels. EC values as high as 18,520 μS/cm indicate groundwater in some locations are unfit for drinking. The average Total Dissolved Solids (TDS) of 1717 mg.L-1 is also indicating non-compliance with standards. Salinity zone maps were developed based on the observations. Further detailed studies need to be conducted to ascertain the factors that influence groundwater salinity, such as geology, island type, and seasonality.

The impact of fruit and vegetable waste is becoming a significant concern for the environment. The biomaterial waste generated from fruit processing industries is very high. When discharged as processed waste, it also increases water pollution. 45% of the total industrial organic pollution originates from food processing industries. These generated wastes are suitable for the production of biochemicals. Pectin is one such biochemical that plays a vital role in reducing the burden on the environment. Pectin helps in the manufacturing of confectionaries. Vegetable waste like beetroot, carrot, beans can also act as a source for pectin production. This study depicts extracting Pectin from mixed fruit pomace waste. Mixed fruit (Orange, Pomegranate, Banana & grapes) pomace waste reacts with 0.1N HCl. This reaction uses a 2-stage crosscurrent solid-liquid extraction technique. For its nature, obtained pectin was tested as calcium pectate using methylated spirit. The filtrate from 2-stage crosscurrent leaching was further dried in an oven. RSM technique helps in optimizing parameters like drying time, temperature, pH, and concentration. The experimental setup generated Pectin gave an efficiency of 11.52% for 22.4g of dried mixed fruit pomace waste.