Wetlands have long played a significant role as natural purification systems. Textile industry processes are among the most environmentally unsustainable industrial processes, because they produce coloured effluents in large quantities polluting water. The aim of this study is to assess the performance of VFCWs to treat two different azo textile dyes with and without artificial wastewater for long periods of time through different operation modes such as contact and resting times, and loading rates, which has rarely been considered in previous research works. The corresponding key objectives are (a) to assess the role of gravel (as a control wetland) and plants on dye reduction and other pollutants; (b) to determine the influence of two groups of dyes (acid (AB113) and basic (BR46)), each dye having a different molecular weight and chemical structure, at two different concentrations (7 mg/l and 215 mg/l); (c) to evaluate the impact of the mixture of both dyes on the performance of vertical-flow constructed wetlands in terms of dye reduction with/without artificial wastewater; (d) to determine the annual and seasonal reduction; and (e) to assess the influence of operational parameters such as contact time (48h and 84h), resting time and mass loading rate on dye reduction and other pollutants for a long period. The first phase dealt with treating the two azo textile dyes only during the period between 1 June 2015 and 31 May 2016, while the second phase dealt with artificial wastewater containing the two azo textile dyes during the period between 1 June 2016 and 31 May 2017. According to the first phase, for the low concentration of BR46, there was no significant (p≥0.05) difference between the wetlands in terms of dye reductions. However, for chemical oxygen demand (COD), the reduction percentages were 50%, 59% and 67% for the control and for the wetlands with short and long contact times, respectively. All reductions were statistically significant (p In the case of phase two, the presence of plants had no effect on the dye and COD reductions. For the low concentration of BR46, the percentage reductions for the dye were 92%, 89% and 91%, and for COD, they were 69%, 82% and 70% for the control, and the short and long contact times, respectively. All reductions were statistically significant (p<0.05). For the high concentration of BR46, the reduction percentages for the dyes were 73% and 33%, and for COD, they were 56% and 39% for the long and short contact times, respectively. For the low concentration of AB113, the percentage reductions for the dye were 85%, 77% and 82%, and for COD, they were 76%, 81% and 62% for the control, and the short and long contact times in this order. For the high concentration of AB113, the percentage reductions for the dye were 44% and 54%, and for COD, they were 40% and 56% for the 48 h and 96 h contact times, correspondingly. Regarding ortho-phosphate-phosphorous for the low concentrations in the case of AB113 and BR46 and the mixture of both dyes, the reduction percentage in wetlands with high contact time was significantly (p<0.05) better than those of the control wetlands and wetlands with low contact time. For the high concentration of BR46, AB113 and the mixture of both of them, wetlands with high resting and contact times had lower ortho-phosphate-phosphorous effluent concentrations when compared with wetlands with low resting and contact times. Regarding ammonia-nitrogen reduction percentages for low concentrations of BR46 and AB113 and the mixture of both dyes, wetlands with high resting times had better reduction percentages (p<0.05) when compared with the control wetlands as well as wetlands with low resting times. In the case of high concentrations for BR46, AB113 and the mixture of both of them, wetlands with low loading rates had a better reduction percentage when compared with wetlands with a high loading rate. Regarding nitrate-nitrogen reductions for low and high concentrations of BR46, AB113 and the mixture of both of them, the reduction percentages for all wetlands were in the range from 75 to 100%. Regarding aromatic amine compound reductions, wetlands with long contact times showed significant (p<0.05) differences when compared with the control and wetlands with short contact times for the low concentrations of BR46 and AB113. For the high concentration of BR46 and AB113, wetlands with low loading rates showed a significant difference (p<0.05) when compared with wetlands with a high loading rate. The researcher recommended that using HPLC combined with FTIR to investigate the reduction in aromatic amines and working on modelling of the results should help the designer in improving the construction of wetlands on an industrial scale.

Azo textile dyes wastewater treatment with constructed wetlands : design and operation of experimental vertical-flow constructed wetlands applied for the treatment of azo textile dyes (with/without artificial wastewater)

There are currently more people than before seeking a livelihood through oil palm agriculture around the world – approximately 14 million people with properties vulnerable to flood risks, and more than half of the settlements contain livelihood assets being exposed to seasonal floods. Flood risks cannot be eliminated but they can be effectively analysed and reduced in many oil-palm dominated landscapes. To assist disaster planning, hazard and risk mitigation, tools and models must be used to understand flood characteristics and behaviour, the areas affected, potential flood risks, levels of exposure and loss probabilities of livelihood assets. However, little is known about riverine flood risk to, and vulnerability of, livelihood assets in oil-palm dominated landscapes. This study assessed flood risks on livelihood assets in the Dagi River catchment, PNG.

Fieldwork data and hydrological models were used to determine flood characteristics and behaviour. Water depths, velocity and duration were observed during two wet seasons in 2010 and 2014. Flood discharge in terms of its peak and magnitude were analysed using rainfall data simulated using HEC-HMS. Both Log-Pearson Type III Distribution and Gumbel's extreme value distribution techniques were used to analyse flood frequency. In HEC-HMS program, the millimetre unit of depth is written as MM (USACE, 2013; p.124). Rainfall-runoff simulation results show that upstream reaches have a steep hydrograph with a peak discharge of 1326m³/s (130.10MM) for 2010 at 13:00pm compared with that of 2014 which peaked at 12:30pm with 729m³/s (86.96MM). Downstream reach generally showed a broader hydrograph with a peak discharge of 1158.4m³/s (72.47MM) at 14:00pm in 2014, while in 2010 it was 2424.4m³/s (109.67MM) that peaked by 14:30pm. Floods in Dagi rise quickly upstream and flow fast downstream and this provides less time for warning and evacuation.

Velocity in all cross-sections decreases towards the banks and in the floodplains as they encounter roughness. The 2014 floods had an average velocity of 4.35m/s in the main channels upstream while downstream average velocity was 2.75m/s. The 2010 floods had an average velocity of 5.38m/s upstream while downstream average velocity was 3.76m/s. The flood duration from upstream in 2014 receded to normal levels in three days (72 hours) but took seven days downstream. In 2010 the flood receded within four days upstream but took 11 days to reach normalcy downstream. Flood height varies for all sites in response to slopes (1-20⁰) from 0.01m to as much as 7.5m. The stream power during the 2014 flood increased from 1915.12 watts/m² (N/m s - where N is expressed as stream power per unit weight of 1 N and work and energy are metres per second written as one unit - m s) from sub-catchment 1 to as much as 9575.58 N/m s at sub-catchment 4. The flood event of 2010 had a recurrence interval of 11 years (9.09%) while that of 2014 had a recurrence interval of 7.33 years (13.64%). This means floods in Dagi catchment are highly variable and this depends on many factors but primarily rainfall and slope characteristics.

SOBEK 1D2D, HEC-RAS Beta 5.0, HEC-RAS 4.1 and HEC-GeoRAS modelling software were used to model and visualise flood inundation and hazards. Modelling focused on flood velocity and depth in 1D and 2D channels, where inundation and hazards were visualised. The spatial extent of inundation and hazards were determined by using flood characteristics (velocity and depth) obtained after the 2010 and 2014 flood simulation. Because of the relatively flat topography (1-20⁰) with no flood protection in all reaches, high peak discharge breached the bankfull stage and inundated within an average radius of 500m. The 2010 flood event inundated a large area (79.9 ha) compared with the 2014 inundation (55.2 ha), with most inundation occurring in the middle and lower reaches. Results validated using depth and velocity data together with various roughness figures revealed a difference, on average, of 0.40m in the modelled and observed data. The peak difference during the 2014 flood event ranged between 0.24m and 0.55m. On average, the 2010 flood revealed a difference of 0.45m in the modelled and observed results and at peak discharges the difference ranged from 0.32m to 0.54m. Thus, the modelled peaks agreed with those observed. The simulated results with appropriate input data, initial condition, boundary conditions, model assumptions, roughness coefficient values and coarse representation of the grid resolution were able to generate a very good simulated flood inundation extent.

Flood risks were assessed using a risk-based approach by analysing risk comprehensively. It estimated flood hazards using geo-processing tools and hydrodynamic models that represented flood intensity. It estimated vulnerability based on the percentage of livelihood assets damaged, dependent on flood velocity and depth. This study used a combination of qualitative and quantitative risk assessment methods. Focusing on depths of inundation and maps of vulnerable land use, an assessment of risks was performed qualitatively. The level of vulnerability and risk zones were identified based on the assigned land use weights, hazard and vulnerability assessment criteria. Using the weights and criteria and land use curves, raster-based vulnerability and risk maps were drawn in relation to three exceedance probabilities. Quantitative risk assessment involved estimating the total costs of exposed elements (direct tangible) based on the damage functions and classified according to their type. Results showed that houses and buildings incurred the greatest costs (34.3%), leaching of fertilisers (27.2%), deaths (23.7%), subsistence gardens (11.4%), roads (2.6%), damaged oil palm trees (0.8%), non-pick-up of bunches (0.02%) and formal job income loss (0.01%). The total economic costs based on the elements at risk is PGK77,869,451. This is equivalent to US$26,545,696 (23rd September 2015 exchange). The results reveal that the level of damage varies with flood probabilities.

Flood risks have been exacerbated by the increasing population and the need for more people to seek a livelihood. This has increased the extent and impacts of floods through the replacement of vegetation with bare and levelled land surfaces associated with increased oil palm cultivation and subsistence gardening in riparian zones. These land uses have interfered with the water cycle and the stream channel morphology. Prevention plans and mitigations recommended for flood disaster should include the implementation of conventional and unconventional structures.

Flood risks on assets and livelihoods in tropical catchments within oil palm landscapes

Textile industries are among the most environmentally unsustainable businesses, releasing large amounts of effluent that endangers ecosystem health. Constructed wetlands (CWs) are low-cost eco-technical treatments for industrial wastewater control. The CWs are self-contained remediation systems that do not require external energy and have basic mechanisms for pollutant removal, such as biological, chemical, and physical processes. For more than sixty years, constructed wetlands have been utilized to clean wastewater. Most applications have been developed to treat municipal or household wastewater, although CWs are now successfully used to treat a wide range of wastewater types. Constructed wetlands were also employed to treat textile industry effluents in the 1990s. The survey indicated that textile manufacturing wastewaters were treated using subsurface and surface-flow wetlands. Both horizontal and vertical flow systems have been designed within subsurface flow-created wetlands. In ad - dition, many hybrid-built wetlands have recently been documented in the literature for textile industrial waste-water treatment. According to the survey, textile industrial wastewater is treated in constructed wetlands on all continents, and this research includes the data from 65 constructed wetlands in 21 nations worldwide. This paper examined the latest improvements and discoveries in CWs and the many types of CWs used for textile wastewater treatment. The paper also demonstrated state-of-the-art integrated technologies for improving the performance and sustainability of CWs, such as CW-MFC systems.

Textile Wastewater Treated by Constructed Wetlands – A Critical Review

Validation of localised coastal wind forecasts for artisan fishers of southwestern India

Bangladesh frequently suffers from acute riverbank erosions and, as a result, every year a large number of people internally migrate to new places mainly in search of livelihoods. While very few studies focus on the multifaceted nature of vulnerability experienced from riverbank erosions, the present study examines to what extent different drivers of vulnerability affect socio-economically disadvantaged internal migrants living in riverbank erosion-prone areas in Bangladesh. Empirical evidence from two north-western riverbank erosion-prone districts in Bangladesh demonstrates that the disadvantaged internal migrants and their household members were exposed to a range of vulnerabilities connected to economic, institutional, infrastructural, environmental, and social drivers. It is contended that evidently there are different types of vulnerability some of which are perceived to be more severe than others in the study areas. This study, therefore, suggests extending some specific support programmes including income generation schemes, access to institutional credit for the landless, improved inexpensive means of transportation, and improved communication. This article also proposes improving rural infrastructure including irrigation facilities, inexpensive transportation means for agricultural inputs or other farming materials, reasonable prices for daily necessities, and improved health care benefits.

https://journals.sagepub.com/doi/pdf/10.1177/09731741221078741

Exploring the Drivers of Vulnerability Among Disadvantaged Internal Migrants in Riverbank Erosion Prone Areas in North-West Bangladesh

The apocalyptic visions of climate change that are projected in the media often involve extreme weather events, disasters and mass migration of poor people. This book takes a critical look at this notion, drawing on research in Bangladesh, a country located at the heart of debates on climate change and migration.

This book argues that rather than leading to dramatic events, climatic and environmental impacts often cause incremental changes in people’s habitats and livelihoods, making them migrate in search of better places and income. With or without climate change, climatic and environmental factors can impoverish people, and drive displacement and migration, especially in the global South. These influences, including disasters, need not necessarily make people move, but instead sometimes trap the poorest and the most vulnerable people in their places exposed to hazards or make them migrate to even riskier places, such as crowded and flood-prone urban slums. This book argues that restrictions placed on people’s mobility options could increase their vulnerability and favours proactive migration policies.

This timely contribution explains the climate-hazard-migration nexus in an accessible, engaging language for students of geography, development studies, politics and environmental studies, as well as humanitarian and development practitioners and policymakers.

Climate, Environmental Hazards and Migration in Bangladesh

/pdf/our-toxic-world-a-guide-to-hazardous-substances-in-our-1jifkieu35.pdf

Our Toxic World A guide to hazardous substances in our everyday lives

Despite recent advances, uptake of climate and weather services is limited for many groups that need forecasts for safe and sustainable livelihoods such as artisanal fishers. On the Arabian Sea coast of southwestern India, for instance, they often fish in foul weather, and risk accidents during the monsoon season marked by high wind and waves. To make forecasts more easily accessible, we tested and deployed a low-cost, web-based, knowledge co-production system called Radio Monsoon. The website offers wind speed and wave height forecasts in graphics and local-language text with multiple interfaces - social media, WhatsApp, and a free phone service using voice over internet protocol. Focus groups and conversations connect the fishers with forecasters in a feedback loop. This paper examines how Radio Monsoon addresses challenges in knowledge co-production by looking at its technology deployment and societal impact.

Disseminating marine weather forecasts and gathering feedback from artisanal fishers in south India

In this article, we reflect on the consequences of COVID-19 interventions on coastal communities in south Kerala (India), and the responses of the local population to the latter. In particular, we map out the events which led to spontaneous protests in a number of fishing villages during the second wave of the epidemic in July 2020. We will show that whilst during the first wave of the epidemic, coastal communities remained supportive of government intervention, such an initial support begun to wane as the epidemic unfolded over time and became more aggressive and widespread. We argue that such a shift in fishing communities’ attitudes was a response not only to the consequences of a more forceful policy of containment of the epidemic but also to a sudden identification of coastal communities as the main locus of contagion in the district. We suggest that the consequent restrictive measures enforced on coastal communities were driven as much by epidemiological concerns as by a media-driven social panic built upon widespread negative stereotypes that have historically worked to marginalize, and even criminalize coastal communities in Kerala. We deploy the notion of bio-moral marginality to reveal ways through which the attribution of specific—and largely stereotyped and negative— physical attributes and moral dispositions to the bodies and behaviour of people belonging to fishing coastal communities constituted the ground upon which the social panic concerning the spread of the COVID-19 virus unfolded in south Kerala, thus leading to fishers’ militant response.

https://journals.sagepub.com/doi/pdf/10.1177/09731741231162446

Covid on the Coast: Pandemic Governance and Protests in Fishing Villages in South Kerala, India

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Climate, Environmental Hazards and Migration in Bangladesh

Our Toxic World A guide to hazardous substances in our everyday lives

Disseminating marine weather forecasts and gathering feedback from artisanal fishers in south India

Covid on the Coast: Pandemic Governance and Protests in Fishing Villages in South Kerala, India