Turning trash into treasure: Torrefaction of mixed waste for improved fuel properties. A case study of metropolitan city.

Solid waste management is one of the biggest challenges of the current era. The combustible fractions in the waste stream turn out to be a good energy source if converted into refuse-derived fuel. Researchers worldwide are successfully converting it into fuel. However, certain challenges are associated with its application in gasifiers, boilers, etc. to co-fire it with coal. These include high moisture content, low calorific value, and difficulty to transport and store. The present study proposed torrefaction as a pretreatment of the waste by heating it in the range of 200 °C-300 °C in the absence of oxygen at atmospheric pressure. The combustible fraction from the waste stream consisting of wood, textile, paper, carton, and plastics termed as mixed waste was collected and torrefied at 225 °C, 250 °C, 275 °C, and 300 °C for 15 and 30 min each. It was observed that the mass yield and energy yield decreased to 45% and 62.96% respectively, but the energy yield tended to increase by the ratio of 1.39. Proximate analysis showed that the moisture content and volatile matter decreased for torrefied samples, whereas the ash content and fixed carbon content increased. Similarly, the elemental analysis revealed that the carbon content increased around 23% compared to raw samples with torrefaction contrary to hydrogen and oxygen, which decreased. Moreover, the higher heating value (HHV) of the torrefied samples increased around 1.3 times as compared to the raw sample. This pretreatment can serve as an effective solution to the current challenges and enhance refuse-derived fuel's fuel properties.

Hydrochemical, hydrogeological, and cancer health risk analysis of groundwater due to anthropogenic activities, Hasilpur, Pakistan.

Drinking water quality deteriorates rapidly due to anthropogenic activities and rapid population growth. These activities, in developing countries, will lead to water scarcity. In Pakistan, 70% of the population has no access to safe water, and people use canal water to drink. This study performed hydrochemical, hydrogeological, and cancer risk analyses on Tahsil Hasilpur, Bahawalpur, Pakistan. Thirteen tube wells were selected for groundwater and borehole log study. Twenty-two drinking water quality parameters were analyzed using standard methods and quality checks. The borehole data (2D and 3D) shows the abundance of sand (fine and coarse) with some uniformities, which changes the groundwater quality. The results of water quality parameters show that the concentration of TDS (2064-11,159 mg/L), Cl-1 (213-4917 mg/L), As+3 (0.048-0.158 mg/L), Pb+2 (1.294-1.673 mg/L), and Cd+2 (0.008-0.053 mg/L) were beyond guideline values. The statistical analysis showed that the parameters have a moderate to strong correlation (Pearson correlation), which may be due to the same origin (ANOVA). The principal component analysis and cluster analysis confirm the multiple sources of pollutants in the groundwater of the study area. The Piper, Durov, Stiff, and Scholler diagrams confirm that the groundwater system has an abundance of Ca+2 and Mg+2 with Cl-1. The Gibbs diagram showed that the groundwater is not saturated and tends to dissolve more minerals. The hazard quotient values are above 1.0, which indicates noncancer risk severity. The HQ trend was As+3 > Pb+2 > Cd+2 > Ni+2 > Cu+2 > Cr+2 > Zn+2 > Fe+2. The cancer risk values showed that 3-5 people/100 population were exposed to cancer risk. The trend of CR was As+3 > Cd+2 > Cr+2 > Pb+2 > Ni+2. The GIP mapping of pollutants showed that the concentration of pollutants near the canals was high compared to the locations away from the canal. The overall groundwater quality is alarming and needs immediate government attention.

Health risk assessment of endocrine disruptor bisphenol A leaching from plastic bottles of milk and soft drinks.

Bisphenol A (BPA) is of major concern to public health due to its toxic potential and xenoestrogenic endocrine-disrupting effect. One of the major sources of BPA comes from the plastic bottles used to pack milk and soft drinks. The purpose of the present study was to assess and compare the risk associated with BPA transfer from plastic bottles to milk and soft drinks being stored in summer and winter conditions. A sensitive and reliable method of solid phase extraction cartridge packed with multi-walled carbon nanotubes (MWCNTs) was employed. In milk samples (supplied in plastic bottles) of winter season, BPA levels were 0.17-0.32 mg/ kg. In milk samples of summer season, BPA levels were 0.77-1.59 mg/ kg. In soft drink samples of winter, BPA levels were between 0.14 and 0.3 mg/kg. While in 4-month-aged summer soft drink samples, BPA levels were 0.7-1.02 mg/kg of food. The daily exposure dose (DED) of BPA in milk samples of winter season was 1.42-2.67 µg/kg which was below the standard tolerable daily intake (TDI) of 50 µg of BPA/kg of body weight as per USEPA. The DED of BPA in milk samples of summer season was 5.58-10 µg/kg of body weight which was also less than TDI. For soft drink samples, BPA from winter samples was ranged from 1.17 to 1.67 µg/kg of body weight while for summer 4-month-aged samples was 2.5-7.08 µg/kg of body weight. Both types of samples were still less than TDI of BPA.