Excessive discharge of poorly treated effluent has impacted global water resource systems intensely. The declining state of wastewater treatment plants (WWTPs) is a significant source of pollution in water resources. There is evidence of water resource quality deterioration in natural environments caused by effluent discharges. We assessed the impact of wastewater treatment effluent on the quality of the Crocodile River. For spatial distribution, we collected data from three WWTPs discharging effluent into the Crocodile River and from three points situated downstream of each WWTP. Physicochemical and microbiological parameters such as pH, electrical conductivity, chemical oxygen demand, phosphates, nitrates, ammonia, and Escherichia coli were analysed using standard methods of the American Public Health Association. The water quality index was also calculated to give an overall indication of pollution within the catchment. The results show that WWTPs were not complying with the effluent standards set out in their water use licence. The WWTP effluent had a negative impact on downstream water quality, with the water quality index indicating low quality of discharged effluent. It is recommended that a regular and consistent water resource quality monitoring programme be implemented, particularly in areas where effluent discharges are prevalent.
Introduction: South Africa has the highest ambient air pollution exposure associated with morbidity in the Sub-Saharan region, accounting for a total number of 14356 confirmed cases of mortality on an annual basis. The study assessed air pollution exposure levels of Khayelitsha and Marconi-Beam neighbourhoods that are not monitored by the fixed-site monitoring station provided by the government. Materials and methods: Weekly ambient air pollution measurements of Particulate Matter less than 2.5 μm (PM2.5) and Nitrogen Dioxide (NO2) were collected at households in neighbourhoods of Khayelitsha and Marconi-Beam during the summer and winter seasons. PM2.5 measurements were collected using Mesa Labs GK2.05 (KTL) cyclone attached to a GilAir Plus air sampling pump. Gases of NO2 were measured using passive diffusive samplers. Data were recorded on a Microsoft Excel 2016 spreadsheet. Statistical analyses were performed using IBM SPSS Statistics 28.0. The outcome of the seasonal exposure levels will be compared with the South African ambient air quality standards to ascertain the risk of potential exposure to significant levels of PM2.5 and NO2 that are hazardous to human health. Results: The results suggest that summer NO2 concentrations in the Khayelitsha neighbourhood ranged between (0 and 28 μg/m3), while in winter NO2 concentrations nearly doubled. A similar trend was observed regarding PM2.5 behaviour with summer overall exposure level of 7 μg/m3 and 13 μg/m3 during winter. Conclusion: Whilst there are no legislative guidelines to compare the measured weekly average results, the concentrations were still lower than the World Health Organization (WHO), and South African air quality standards values for PM2.5 and NO2 pollutants.
Purpose To investigate whether soil clay content, cultivar and seasonal variation have any effect on soil CO2 emission rates and leaf CO2 assimilation rates in a drip-irrigated commercial Citrus sinensis orchard. Methods The study was carried out in the field as a randomised complete block design in a 2 × 2 factorial consisting of two soil types and two citrus cultivars on a drip-irrigated commercial Citrus sinensis orchards with 2-week interval measurements of soil CO2 emission and leaf gas exchanges for a year. Results Soil clay content did not influence plant CO2 assimilation rates and soil CO2 emission rates in irrigated citrus. However, seasonal variation significantly influenced both processes. Soil CO2 emission rates were highest in summer and were more than double the rates observed in winter while leaf CO2 assimilation rates were highest in autumn and four times higher than the winter season rates. Mean seasonal soil CO2 emission rates were strongly influenced by mean minimum seasonal temperatures while leaf CO2 assimilation rates only showed a relatively weak relationship with mean maximum seasonal temperatures. Conclusions Soil clay content did not influence soil CO2 emission and assimilation rates in drip irrigated citrus suggesting a non-significant effect of clay content for soils subjected to similar management practices. Citrus CO2 assimilation rate peaks in the autumn while soil CO2 emission rates peak in summer. A snapshot analysis of CO2 sequestration rates suggests that irrigated citrus orchards are net sinks of CO2 in summer, autumn and winter season.
Water quality is declining due to the rise of urbanization, overpopulation, industrial production, climate change, non-compliance of wastewater treatment plants, and agricultural waste. The mushrooming of informal settlements along the bank of the Diep River due to population growth in Dunoon compromises the quality of water. Inadequate sanitation and waste disposal practices in the Dunoon informal settlement are a major problem, leading to the contamination of water resources. This research aimed to investigate the impact of Dunoon informal settlement on the Diep River water quality. Water samples were collected for 4 months from four sites of the river to cover the spatial distribution. The laboratory determined the concentrations of nitrates, phosphates, dissolved oxygen, chemical oxygen demand, total suspended solids, and E. coli, while the field study used a multiparameter reader to determine turbidity, temperature, electrical conductivity, pH, salinity, and dissolved oxygen. The results were compared with the South African water quality guidelines for irrigation, recreation, and aquatic ecosystems, and South African National Standards. The study revealed that the average concentrations of E. coli, dissolved oxygen, electrical conductivity, salinity, turbidity, chemical oxygen demand, and ammonia exceeded the recommended limits in both the wet and dry seasons. Based on the findings, the water quality in Diep River is poor and the Dunoon informal settlement has contributed to this to some extent. The pollution of the river may be linked to health problems and environmental degradation. Considering this, the waste discharged into the neighbouring aquatic environments needs to be monitored and managed frequently.
Since food waste is a contemporary and complicated issue that is widely debated across many societal areas, the world community has designated the reduction of food waste as a crucial aspect of establishing a sustainable economy. However, waste management has numerous challenges, such as inadequate funding, poor waste treatment infrastructure, technological limitations, limited public awareness of proper sanitary practices, and inadequate legal and regulatory frameworks. A variety of microorganisms participate in the process of anaerobic digestion, which can be used to convert organic waste into biogas (e.g., methane) and nutrient-rich digestate. In this study, we propose a synergy among multiple disciplines such as nanotechnology, omics, artificial intelligence, and bioengineering that leverage anaerobic digestion processes to optimize the use of current scientific and technological knowledge in addressing global food waste challenges. The integration of these fields carries with it a vast amount of potential for improved waste management. In addition, we highlighted the relevance, importance, and applicability of numerous biogas-generating technologies accessible in each discipline, as well as assessing the impact of the COVID-19 epidemic on waste production and management systems. We identify diverse solutions that acknowledge the necessity for integration aimed at drawing expertise from broad interdisciplinary research to address food waste management challenges.
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