Inoculum plays a vital role in providing initial microbial population in anaerobic process. There is unavailability of standard inoculum in the Pakistan and the available inoculum requires pretreatment and preparation before use. Thus, in this study the effect of inoculum type and organic loading (OL) on the biogas yield of sunflower meal and wheat straw was evaluated. For this purpose, lab scale batch experiments were conducted at OL of 2 g VS L^− 1 in 225 mL glass bottle using digested manure, acclimatized sludge and septic tank sludge as inoculum. The highest biogas yield and volatile solids reduction of 768 NmL g^− 1 VS and 78%, respectively, were observed from sunflower meal with digested manure. Reactor inoculated with digested manure also showed better buffering capacity in terms of pH. The inoculum selected from first experiment was used to study the effect of OL (2, 6, 10 and 14 g VS L^− 1) on biogas yield. Results showed that biogas yield decreased with the increased in OL. Stability parameters revealed that reactors can be operated safely up to OL of 10 g VS L^− 1. Biogas production data were modelled by modified Gompertz function.

Open dumping and disposal of waste iron ore in freshwater and landfills are increasing environmental concerns. Therefore, following the environmental sustainability and circular economy approach, this study recovered iron-based coagulants from waste laterite ore (WLO) and assessed their performance in water treatment. Chemical leaching of WLO was performed using HCl with varying acid concentrations, temperatures, and treatment times. The optimum iron solubilization efficiency of 86% was achieved at an optimized HCl concentration of 13 mol/L, a reaction temperature of 90 °C, a mixing speed of 500 rpm, and a treatment time of 240 min. The recovered WLO-based iron coagulant exhibited a greenish color and showed promising performance in treating water from the River Indus Canal, particularly in removing turbidity and heavy metals. This performance of the WLO-based iron coagulant was nearly identical to that of conventional ferric chloride. Overall, recovering iron-based coagulants from WLO may reduce the cost of coagulating drinking water or wastewater. Furthermore, the present study’s findings will be useful in protecting the environment by either not discharging the WLO into freshwater bodies or by dry stacking.

The presence of low nutrient content in the lignocellulosic biomass, such as canola straw (CS), limits its anaerobic biodegradability. Therefore, the main focus of the study is to enhance the nutrient content during anaerobic digestion (AD) of CS. For this purpose, three different inoculum sources such as anaerobically digested manure (ADM), acclimatized sludge (AS), and mixed inoculum (MI), and different concentrations of laterite powder (2, 4, 6, 8, and 10%) were added to enhance the batch AD of CS. Results of the study revealed that the reactor inoculated with ADM performed better, and 15.23% and 10.31% higher biogas yields were observed from the reactors inoculated with AS and MI. Moreover, the 2% addition of laterite powder and ADM as inoculum produced the highest biogas yield of 602 NmL/gVS with a 76.4% VS reduction due to the synergistic effect. In addition, reactors showed better buffering capacity and stability in terms of volatile fatty acids to alkalinity ratios due to the addition of laterite powder during AD of CS. Furthermore, characterization of laterite revealed the presence of an iron source, which created the favourable environment for methanogenesis due to direct interspecies electron transfer (DIET). Biokinetic parameters revealed that the modified Gompertz model (MGM) reproduced the biogas production data. In conclusion, AD of CS may be enhanced by using good-quality inoculum and the addition of lateritic mineral. The addition of microbially active inoculums and laterite powder as a nutrient source may also enhance the anaerobic digestate quality and may be used as fertilizer.

In coal mining industry occupational health and hygiene are critical concerns due to the high risk of exposure to hazardous working conditions. This present study evaluates the health and hygiene practices among coal mine workers at the Lakhra Coal Field (LCF) in Pakistan through a structured questionnaire-based cross-sectional survey. A total of 65 questionnaire surveys were distributed among the respondents and 62 were received back. The questionnaire was translated into the local language and distributed among the respondents. Reliability of the questionnaire was assessed using Cronbach Alpha. Demographic analysis revealed that majority of employees were middle-class except managers. Results of the study revealed that a significant proportion (96.77%) of miners were aware of the major health risks associated with mining activities. Moreover, another important finding was noticed that at LCF approximately 97% of respondents answered in the favor that companies were providing them with the routine health checkup facilities. Miners were using personal protective equipment (PPEs) and drinking water with poor quality was available. The study highlights critical gaps in hygiene and health practices in underground mines. These important findings further provide a foundation for policy frameworks aimed at enhancing the standards of occupational health, safety and hygiene of coal workers. Therefore, further studies must be conducted to overcome the issues of health, safety and hygiene in the life of miners.