9 research outputs found
Distribution and Microplastic Pollution and Its Associated Heavy Metal Contamination from an Urban Canal: A Case Study of Saen Saeb Canal, Thailand
No full text Microplastics are emerging as a widespread environmental contaminant in all ecological systems, including the aquatic environment. This study examined the distribution of microplastics, and heavy metals extracted from microplastics, on the surface water of Saen Saeb canal. This canal is subjected to many human activities and has a large accumulation of garbage. Samples of microplastics were collected by a modified pump. The average microplastics concentrations were 479 p/m3 or 0.0856 g/m3 (size of 1-0.3 mm) and 261 p/m3 or 0.0415 g/m3 (size of 0.3-0.1 mm). The dominant colors of these microplastics were transparent-brown and transparent. These microplastics are related to land-based sources which break into secondary microplastics. Film and fiber/line were predominantly investigated in the surface water sample. Their chemical structures were analyzed by Fourier Transformed Infrared Spectroscopy (FTIR) which were confirmed to be polymeric with polypropylene (PP) and polyethylene (PE) being the most abundant. Heavy metals (cadmium, copper, lead, chromium and zinc) were also detected in the microplastics. Since this urban canal connects two main rivers which flow into the Gulf of Thailand, many aquatic organisms in the river might have an effect on this pollution. The results of this study showed that a strong recommendation to enforce the improvement of solid waste collection to prevent pollutants from entering the environment is necessary.
Keywords: microplastics, Saen Saeb canal, heavy metal, plastic debris, FTI
Marine Plastics Abatement
No full textMarine Plastics Abatement Volume 1 provides comprehensive knowledge of plastic pollutions in marine ecosystems and their implications on human health, especially from the contamination of micro and nano-plastic particles by which the levels of plastic pollutions in marine, aquatic, terrestrial and atmospheric systems are described. In addition to emerging challenges by plastic pollution, this volume offers comprehensive assessment tools as well as practical models on "Circular Economy" with interesting real-world case studies and theoretical and numerical questions and solutions, recent scientific information, and practical exercises, to ensure a user-friendly text for readers
Marine Plastics Abatement
No full textMarine Plastics Abatement Volume 1 provides comprehensive knowledge of plastic pollutions in marine ecosystems and their implications on human health, especially from the contamination of micro and nano-plastic particles by which the levels of plastic pollutions in marine, aquatic, terrestrial and atmospheric systems are described. In addition to emerging challenges by plastic pollution, this volume offers comprehensive assessment tools as well as practical models on "Circular Economy" with interesting real-world case studies and theoretical and numerical questions and solutions, recent scientific information, and practical exercises, to ensure a user-friendly text for readers
Marine Plastics Abatement
No full textMarine Plastics Abatement Volume 2 focusses on abatement strategies and up-to-date technological innovations against marine plastic pollution such as resource recovery, plastics-to-values, co-processing, dumpsite recovery, etc. With an understanding of technological solutions and proper management practices, this volume suggests ways to develop businesses from plastic wastes with several cases from developed and developing countries. Furthermore, business case studies are presented along with recent scientific information, and practical exercises together with discussions on future trends such as introduction of biodegradable, or decomposable plastics; product designs for recycling/upcycling; etc
Unveiling microfiber emissions: A comprehensive analysis of household washing activities and mitigation measures
No full textThe shedding of microfibers from synthetic textiles during laundry significantly contributes to microplastic pollution in various environments. Despite growing awareness, the contribution of microfiber emissions from actual household washing machines and the potential influences of washing activities on their release remain inadequately understood. This study aims to quantify and characterize microfibers generated from different washing programs in actual household washing activities. It proposes optimal conditions for washing machine activities to effectively mitigate the environmental consequences of microfiber contamination using Response Surface Methodology (RSM). The results indicated that types of washing machines, speed of configuration and cycle duration significantly impact on microfiber release quantities. The estimated microfiber releases for the daily, quick, and delicate programs from the front-loading machine were 62.82 ± 6.29 mg/kg, 48.56 ± 15.85 mg/kg, and 12.73 ± 3.04 mg/kg, while the top-loading machine exhibited microfiber release levels of approximately 69.26 ± 3.44 mg/kg, 38.35 ± 5.54 mg/kg and 7.50 ± 2.51 mg/kg, as washing load of 4.21 kg, respectively. Polyester was identified as the predominant polymer, with an average fiber length of 1915 μm. The dominant colors of the fragments are white, dark blue, and red, which are related to the original household textiles test. The optimal conditions for reducing microfiber emissions include using a rotational speed of 1450 rpm and a cycle duration of 1.7 hours, alongside selecting appropriate washing programs with optimal durations to minimize releases during household laundry
Organic Matter, Solid and Pathogen Removals from Black Water in a Pilot-Scale Solar Septic Tank
No full textDemonstrating the operational feasibility of a solar-powered septic tank as an alternative and sustainable sanitation option for communities was presented in this study. The efficiency and technical feasibility of a solar septic tank (SST) were tested and evaluated in pilot scale for treatment of black water from communal toilets. The system consisted of a modified septic tank equipped with a disinfection chamber inside the tank. Solar radiation was collected as a heat source for heating and disinfection. The system could achieve high removal efficiencies of total chemical oxygen demand (TCOD), 5-day biological oxygen demand (BOD5), total solid (TS), and total volatile solid (TVS) of 97%, 94%, 91% and 96%, respectively. The inactivation efficiencies of E. coli and total coliforms in the SST were about 2.2 log reduction. The increased temperature inside the septic tank could help to inactivate pathogens and reduce the environmental issues related to conventional fecal sludge management. In turn, this improved the water quality of groundwater and surface water and minimize health risks. Influence of operational conditions including organic/nutrient loading rate and ratio between TCOD and TKN in the black water on the performance of the SST were discussed
‘Solar septic tank’: evaluation of innovative decentralized treatment of blackwater in developing countries
No full textAn innovative decentralized wastewater treatment system, namely the ‘Solar Septic Tank (SST)’, was constructed and tested at the household scale in a community in central Thailand. This study aimed to investigate the long-term performance of the SST in treating blackwater subject to year-round variation. Results of the 3-year continuous operation and monitoring showed significant improvement in the SST effluent quality with the potential to minimize environmental problems and public health risks. The SST achieved significantly higher total chemical oxygen demand, soluble chemical oxygen demand, total biochemical oxygen demand (TBOD), soluble biochemical oxygen demand, total kjeldahl nitrogen, total solid and total volatile solid removal efficiencies than a conventional septic tank (CST). The average TBOD concentration of the SST effluent was 150 ± 75 mg/L, meeting the Thai discharge standard (less than 200 mg/L of TBOD), while the average TBOD concentration of the CST was 240 ± 140 mg/L, higher than the Thai discharge standard. The Escherichia coli inactivation in the SST was 1–2 log reduction more than that in the CST. The removal efficiencies of TBOD and pathogens exhibited positive correlation with the ratios of the SST temperature
intI1 gene abundance from septic tanks in Thailand using validated intI1 primers.
No full textAntimicrobial resistance (AMR) poses a serious global health threat, and wastewater treatment (WWT), including septic tanks, is a source of AMR. In Thailand, antibiotics are unregulated, and septic tanks are commonly used. Yet, their impact on the spread or mitigation of AMR is unknown. We monitored household and healthcare conventional septic tanks (CST) and household solar septic tanks (SST) in Thailand using the class 1 integron-integrase (intI1) gene abundance as a proxy for AMR. A systematic review of the literature found 65 intI1 primers. We evaluated the coverage and specificity of each, including a new MGB TaqMan primer-probe, against clinical and environmental intI1, intI1-like, and non-intI1 databases. The three best primers were selected, laboratory validated for DNA and mRNA quantification, and used to quantify septic tank intI1 gene abundance. No primer set could distinguish between intI1 and intI1-like sequences. While primer choice did not affect gene abundance of the same sample (P-value > 0.05), sometimes when comparing the same samples quantified by different primers, statistical differences were observed for one but not the other primer set. This may lead to different interpretations of AMR risk. Irrespective of primers or reactor type intI1 gene abundance was greatest in influent > effluent > sludge. intI1 gene abundance was lowest in the effluent of the SST-household < CST-household < CST-healthcare. 31% to 42% of intI1 was removed by the CST-household tank, indicating while septic tanks remove some intI1 they remain a source to the surrounding environment. Toward the goal of achieving standardization across studies, we recommend the F3-R3 primer for intI1 quantification
Solar Septic Tank: next generation sequencing reveals effluent microbial community composition as a useful index of system performance
No full textSeptic tanks are widely deployed for off-grid sewage management but are typified by poor treatment performance, discharge of polluting effluents and the requirement for frequent de-sludging. The Solar Septic Tank (SST) is a novel septic tank design that uses passive heat from the sun to raise in-tank temperatures and improves solids degradation, resulting in a cleaner effluent. Treatment has been shown to exceed conventional systems, however, the underlying biology driving treatment in the system is poorly understood. We used next generation sequencing (Illumina Miseq (San Diego, CA, USA), V4 region 16S DNA) to monitor the microbiology in the sludge and effluent of two mature systems, a conventional septic tank and an SST, during four months of routine operation in Bangkok, Thailand, and evaluated the ecology against a suite of operating and performance data collected during the same time period. Significant differences were observed between the microbiome of the sludge and effluent in each system and the dominant taxa in each appeared persistent over time. Furthermore, variation in the microbial community composition in the system effluents correlated with effluent water quality and treatment performance parameters, including the removal of chemical and biochemical oxygen demand and the concentration of fecal and total coliforms in the effluent. Thus, we propose that a wide-scale survey of the biology underlying decentralised biotechnologies for sewage treatment such as the SST could be conducted by sampling system effluent rather than sampling sludge. This is advantageous as accessing sludge during sampling is both hazardous and potentially disruptive to the anaerobic methanogenic consortia underlying treatment in the systems
