Are Green Jobs Sustainable for Sri Lankan Economy?

It is imperative that Sri Lanka grasps the concepts of green jobs to meet the most vital but intricatechallenge of the 21st Century, which is the transformation to a sustainable and a low-carbon economy.Such a transformation or a paradigm shift, which can be gradual or rapid depending on the circumstances,will undoubtedly have a considerable positive effect on the way we produce and/or consume goods andservices. The speed at which this transformation would occur is likely to accelerate in the near future asthere is a trend of global transition from a traditional to a low-carbon economy, in order to attainsustainable economies. Such trends will help create an array of different forms of green jobs across manysectors, and most probably can become a catalyst for further development. The International LabourOrganization (ILO) has defined green jobs as “Jobs created when they help in reducing the negativeenvironmental impacts ultimately leading to environmentally, economically and socially sustainableenterprises and economies”. Green jobs, in general, stand on two pillars: decent work and environmentalsustainability. Thus, green jobs can be defined as decent work that contributes to environmentalsustainability. In a broader sense decent work needs to address the core of international labour standardssuch as freedom of association and effective recognition of the right to collective bargaining, eliminationof all forms of forced or compulsory labour, effective abolition of child labour, elimination ofdiscrimination in respect of employment and occupation, occupational health and safety, etc. whilstaligning to laws applicable to Sri Lanka. Environmental sustainability addresses issues such as effectivelycombating climate change, pollution prevention and control, conservation of eco-systems and biodiversityetc. (ILO, 2007)

Zinc adsorption by lowcost sorbent materials: clay tile, Brick, sawdust and rice husk

It has been found over the past couple of years rapid growth of population, industrialization and urbanization has first and foremost contributed to the severe water pollution in both surface and ground water. The health hazards associated with heavy metals have been on the rise, particularly the chronic diseases. Lack of tertiary treatment of wastewater may have contributed to this emergent problem, adsorption process is considered as the best available water treatment method and activated carbon has proven to be the best sorbent material which can be used in removing wide variety of pollutants. However, usage of this activated carbon becomes restrict due to its high cost and regeneration cost. Therefore, the present study focuses on low-cost sorbent materials: viz., clay tile, brick, sawdust and rice husks. Laboratory-scale experiments were performed with a synthetic Zinc solution. Results revealed that clay tile material has the highest adsorption capacity (47.6 mg/g) and removal efficiency, (98%), while brick (37.0 mg/g, 86%), sawdust (20.4 mg/g, 80%) and rice husks (15.8 mg/g, 64%) have relatively low adsorption capacities and removal efficiencies, respectively. The separation factor of equilibrium (RL) indicates favourable isotherms (0< RL<1) for all tested sorbent materials. Among the studied materials clay tile, brick and rice husks are good adsorbent for Zinc (n>2) while sawdust is a moderately difficult material for adsorption of Zinc (n <2)

Investigation of Zinc removal capacities of different sorbent materials to be used in constructed wetlands

ABSTRACTIt has been found over the past couple of years that health hazards associated with heavy metals havebeen on the rise, particularly the chronic diseases. Lack of tertiary treatment of wastewater may havecontributed to this emergent problem, mainly due to the high costs involved in the removal of heavymetals. Constructed wetlands have therefore received great attention as a tertiary treatment method ora polishing technique of wastewater due to its low construction and operation costs. However, findinga low-cost sorbent material to be used as the wetland filter material, which can be used as analternative to activated carbon, has been a problem for decades. Therefore, the present study focuseson applicability of low-cost sorbent materials: viz., clay tile, brick, saw dust and rice husks, as filtermediums. Laboratory-scale experiments were performed with a synthetic Zinc solution. Resultsrevealed that clay tile material has the highest adsorption capacity (47.6 mg/g) and removal efficiency,(98%), while brick (37.0 mg/g, 86%), sawdust (20.4 mg/g, 80%) and rice husks (15.8 mg/g, 64%)have relatively low adsorption capacities and removal efficiencies, respectively. The separation factorof equilibrium (RL) indicates favourable isotherms (0&lt; RL&lt;1) for all tested sorbent materials. Amongthe studied materials clay tile, brick and rice husks are good adsorbents for Zinc (n&gt;2) while sawdustis a moderately difficult material for adsorption of Zinc (n &lt;2).Keywords: adsorption isotherms, constructed wetlands, sorbent material, Zin

Water balance and renewal time of rekawa lagoon, Sri Lanka; a restorative approach

Rekawa Lagoon is a chocked and shallow coastal water body located in the southern coast of Sri Lanka. It is relatively unusual in that the major freshwater input, Kirama-oya river connects through the constricted channel much closer to the inlet at seaward end. A causeway was constructed, around 700 m from the lagoon inlet to the inland, across the constricted channel with an effort to link a secluded Kapuhenwala village with the rest of the area which in turn greatly reduced the volume and speed of water entering and leaving the lagoon system. Construction of the causeway led to many environmental problems with poor flushing efficiency and hampering to and fro movement of the prawns in the lagoon. The aim of this study was to evaluate the present situation and propose alternative management scenarios for improvement of water flow and lagoon ecosystem. The implications of different development stages of the causeway were discussed in terms of field measurements supported by modeling to describe the water balance and the water renewal time. The alternative of modifying the existing causeway was proposed to increase the free water flow at the inlet that favors recruitment of juvenile shrimp species

Use of Photocatalysis for Degradation of Glyphosate in Potable Water of CKDu Prevalent Areas

Glyphosate, which is commercially available as Roundup®, was the most widely used herbicide in Sri Lanka until recently. Recent studies report the presence of glyphosate in different water sources (drinking water, surface water, groundwater) in the Chronic Kidney Disease of unknown etiology (CKDu) prevalent areas containing elevated hardness levels. Additionally, WHO studies conducted in 2013, provide evidence of the presence of glyphosate in trace levels in urine samples of CKDu subjects. Thus, glyphosate is suspected to be one of the causal factors for CKDu and its removal, when present in potable water with high hardness levels, is a challenging engineering task. Photocatalysis is recognised to be one of the promising technologies for degradation of glyphosate. Hence, this study focuses on investigating the effectiveness and efficiency of the photocatalysis process for degradation of glyphosate from potable waters containing high hardness levels. Experiments were conducted with high purity Glyphosate and Roundup® in the absence (0 mg/l as CaCO3) and presence of hardness (1,500 mg/l as CaCO3). A sunlight activated water purifier bag available in the market that consists of a Titanium Dioxide membrane was used for application of the photocatalysis process. A 3.0 L water sample containing Glyphosate/Roundup® (glyphosate concentration 1 mg/L) was continuously exposed to sunlight for six (06) hours. A solar irradiance meter was used to measure the sunlight intensity. Samples from the reaction solution were collected at predetermined time intervals and analysed for glyphosate and amninomethyphosphonic acid (AMPA) using GC/MS and LC/MS in the absence and presence of hardness, respectively. A rapid decrease in glyphosate concentration to levels below 0.7 mg/l (USEPA Maximum Contaminant Level) was observed during the first 60 minutes of reaction time under all experimental conditions studied. The concentration of AMPA detected was below the level of quantification in all experiments implying that complete degradation of Glyphosate has occurred until inorganic phosphate is produced. When using high purity glyphosate or Roundup®, slower degradation rates were observed in the presence of hardness compared to that in the absence of hardness. Retardation of glyphosate degradation in the presence of hardness could be attributed to the enhanced persistence of glyphosate due to the formation of glyphosate-Ca and -Mg complexes when hardness is present in water. Similarly, slower degradation rates were observed with Roundup® compared to that of with high purity glyphosate, both in the absence and presence of hardness. The presence of the major adjuvant surfactant [polyethoxylatedtallowamine, (POEA)], which is introduced as an inert ingredient during Roundup® production seems to have enhanced the persistence of glyphosate in water thus causing retardation of Glyphosate degradation by the photocatalysis process. In conclusion, photocatalysis is an effective and efficient technique that could be used to degrade glyphosate in potable water of CKDu prevalent areas in spite of the possible antagonistic effects observed on Glyphosate degradation due to the presence of hardness and/or surfactants.Keywords: CKDu, Glyphosate, Photocatalysi

The Effect of Structural Complexity, Prey Density, and “Predator-Free Space” on Prey Survivorship at Created Oyster Reef Mesocosms

Interactions between predators and their prey are influenced by the habitat they occupy. Using created oyster (Crassostrea virginica) reef mesocosms, we conducted a series of laboratory experiments that created structure and manipulated complexity as well as prey density and “predator-free space” to examine the relationship between structural complexity and prey survivorship. Specifically, volume and spatial arrangement of oysters as well as prey density were manipulated, and the survivorship of prey (grass shrimp, Palaemonetes pugio) in the presence of a predator (wild red drum, Sciaenops ocellatus) was quantified. We found that the presence of structure increased prey survivorship, and that increasing complexity of this structure further increased survivorship, but only to a point. This agrees with the theory that structural complexity may influence predator-prey dynamics, but that a threshold exists with diminishing returns. These results held true even when prey density was scaled to structural complexity, or the amount of “predator-free space” was manipulated within our created reef mesocosms. The presence of structure and its complexity (oyster shell volume) were more important in facilitating prey survivorship than perceived refugia or density-dependent prey effects. A more accurate indicator of refugia might require “predator-free space” measures that also account for the available area within the structure itself (i.e., volume) and not just on the surface of a structure. Creating experiments that better mimic natural conditions and test a wider range of “predator-free space” are suggested to better understand the role of structural complexity in oyster reefs and other complex habitats

Predicting predatory impact of juvenile invasive lionfish (Pterois volitans) on a crustacean prey using functional response analysis: effects of temperature, habitat complexity and light regimes

The ecological implications of biotic interactions, such as predator-prey relationships, are often context-dependent. Comparative functional responses analysis can be used under different abiotic contexts to improve understanding and prediction of the ecological impact of invasive species. Pterois volitans (Lionfish) [Linnaeus 1758] is an established invasive species in the Caribbean and Gulf of Mexico, with a more recent invasion into the Mediterranean. Lionfish are generalist predators that impact a wide range of commercial and non-commercial species. Functional response analysis was employed to quantify interaction strength between lionfish and a generic prey species, the shrimp (Paleomonetes varians) [Leach 1814], under the contexts of differing temperature, habitat complexity and light wavelength. Lionfish have prey population destabilising Type II functional responses under all contexts examined. Significantly more prey were consumed at 26 °C than at 22 °C. Habitat complexity did not significantly alter the functional response parameters. Significantly more prey were consumed under white light and blue light than under red light. Attack rate was significantly higher under white light than under blue or red light. Light wavelength did not significantly change handling times. The impacts on prey populations through feeding rates may increase with concomitant temperature increase. As attack rates are very high at low habitat complexity this may elucidate the cause of high impact upon degraded reef ecosystems with low-density prey populations, although there was little protection conferred through habitat complexity. Only red light (i.e. dark) afforded any reduction in predation pressure. Management initiatives should account for these environmental factors when planning mitigation and prevention strategies

Dealing with algal toxins and dissolved organics in drinking water

Several types of cyanotoxins found in surface water bodies are recognized as having human health effects, whereas taste and odor affect the palatability of water and give rise to public complaints. Conventional water treatment unit operations may be effective in removing the cyanobacteria cells, but cyanotoxins and dissolved organics are not targeted for removal by them. Special treatment units need to be introduced to deal with these substances and attention paid to the process design as many operational issues may be encountered. We used a water supply project in the Eastern Province of Sri Lanka as a case study to investigate the performance of unit operations in water reatment plants for which the source is shallow surface water sources with high inflows of nutrients. The present case study was designed to evaluate the efficacy of prechlorination, activated carbon adsorption, dissolved air flotation (DAF), filtration and disinfection in removal of cyanotoxins, and taste and odor causing dissolved organic substances from the source water. Raw water quality was evaluated using algal concentration, algal toxin concentration, and chemical oxygen demand. To evaluate the efficacy of treatment operations, the sequence of initial unit operation was changed on each day as with prechlorination and with powdered activated carbon (PAC), with prechlorination and without PAC, without prechlorination and with PAC, and without prechlorination and without PAC. In addition, laboratory analysis was done to obtain adsorption isotherms using three types of different PAC. The primary findings of our study were that PAC was effective in removal of Microcystin and chemical oxygen demand (COD) but needs to be optimized by providing sufficient contact time, and prechlorination does not improve the performance, whereas postchlorination is effective in removing any traces of Microcystin left after PAC. 001: 10.10611 (ASCE)HZ.21S3-SS1S.0000114. © 2012 American Society of Civil Engineers

Are Green jobs sustainable for Sri Lankan Economy?

It is imperative that Sri Lanka grasps the concepts of green jobs to meet the most vital but intricate challenge of the 21st Century, which is the transformation to a sustainable and a low-carbon economy. Such a transformation or a paradigm shift, which can be gradual or rapid depending on the circumstances, will undoubtedly have a considerable positive effect on the way we produce and/or consume goods and services. The speed at which this transformation would occur is likely to accelerate in the near future as there is a trend of global transition from a traditional to a low-carbon economy, in order to attain sustainable economies. Such trends will help create an array of different forms of green jobs across many sectors, and most probably can become a catalyst for further development. The International Labour Organization (ILO) has defined green jobs as “Jobs created when they help in reducing the negative environmental impacts ultimately leading to environmentally, economically and socially sustainable enterprises and economies”. Green jobs, in general, stand on two pillars: decent work and environmental sustainability. Thus, green jobs can be defined as decent work that contributes to environmental sustainability. In a broader sense decent work needs to address the core of international labour standards such as freedom of association and effective recognition of the right to collective bargaining, elimination of all forms of forced or compulsory labour, effective abolition of child labour, elimination of discrimination in respect of employment and occupation, occupational health and safety, etc. whilst aligning to laws applicable to Sri Lanka. Environmental sustainability addresses issues such as effectively combating climate change, pollution prevention and control, conservation of eco-systems and biodiversity etc. (ILO, 2007)

Investigation of Zinc removal capacities of different sorbent materials to be used in constructed wetlands

It has been found over the past couple of years that health hazards associated with heavy metals have been on the rise, particularly the chronic diseases. Lack of tertiary treatment of wastewater may have contributed to this emergent problem, mainly due to the high costs involved in the removal of heavy metals. Constructed wetlands have therefore received great attention as a tertiary treatment method or a polishing technique of wastewater due to its low construction and operation costs. However, finding a low-cost sorbent material to be used as the wetland filter material, which can be used as an alternative to activated carbon, has been a problem for decades. Therefore, the present study focuses on applicability of low-cost sorbent materials: viz., clay tile, brick, saw dust and rice husks, as filter mediums. Laboratory-scale experiments were performed with a synthetic Zinc solution. Results revealed that clay tile material has the highest adsorption capacity (47.6 mg/g) and removal efficiency, (98%), while brick (37.0 mg/g, 86%), sawdust (20.4 mg/g, 80%) and rice husks (15.8 mg/g, 64%) have relatively low adsorption capacities and removal efficiencies, respectively. The separation factor of equilibrium (RL) indicates favourable isotherms (0< RL<1) for all tested sorbent materials. Among the studied materials clay tile, brick and rice husks are good adsorbents for Zinc (n>2) while sawdust is a moderately difficult material for adsorption of Zinc (n <2)