Biomethane production from macroalgae

Irish brown seaweeds have been identified as a potential bio-resource with potentially high specific methane yields. Anaerobic digestion is deemed the most feasible technology due to its commercial viability for handling such wet feedstock. However, the biomethane potential of seaweed is highly dependent on its chemical composition which can vary by species type, cultivation method, and time of harvest. This study aims to investigate and optimize the process for the production of biomethane from Irish brown seaweeds focusing on the key technology bottlenecks including for seaweed characterization, biomethane potential assessment, optimization of long-term anaerobic digestion and suitable pre-treatment technologies to enhance potential gas yields. Laminaria digitata and Ascophyllum nodosum were tested for seasonal variation. From the characterization and batch digestion of L. digitata, August was found to be the optimal month for harvest due to high organic matter content, low level of ash and ultimately highest biomethane yield. The specific methane yield of 53 m3 CH4 t-1 wwt in August was 4.5 times higher than the yield in December (12 m3 CH4 t-1 wwt), with ash content the key factor in seasonal variation. For A. nodosum, the optimal harvest month was October with polyphenol content found to be a more influential factor than ash. The gross energy yields from both species were evaluated in the range of 116-200 GJ ha-1 yr-1. Continuous digestion trials were subsequently designed for S. latissima and L. digitata to optimize the key digestion parameters. Results from mono-digestion and co-digestion with dairy slurry revealed that both seaweeds could be digested at maximum biomethane efficiency to a loading rate of 4 kg VS m-3 d-1. Accumulation of salt in the digesters was a concern for long term digestion and it was reasoned that suitable pretreatment may be required prior to digestion. Various pre-treatments were subsequently tested on L. digitata to enhance the gas yield. It was found that maceration after hot water washing yielded 25% more specific methane and up to 54% salt removal as compared to untreated L. digitata. The experiments undertaken aim to assist in providing a basic guideline for feasible design and operation of seaweed digesters in Ireland

The Relationship between Capital Flight, Labor Migration and Economic Growth

Capital flight and labor migration have been increasing in developing nation like Pakistan. This study is used to check the relationship between capital flight, labor migration and economic growth of Pakistan. Time series data is used from 1983-2014 for variables like unemployed labor, capital outflow, unemployment and political instability. Different techniques such as unit root test, granger causality test, ordinary least square and two stages least square are used. Granger causality test showed that capital flight and economic growth have bidirectional causality, while labor migration and economic growth showed unidirectional causality. Two stage least square showed that political instability, labor migration, capital flight and unemployment have the negative impact on the economic growth of Pakistan. Political and security situation should be improved for better economic growth

The Relationship between Capital Flight, Labor Migration and Economic Growth

Capital flight and labor migration have been increasing in developing nation like Pakistan. This study is used to check the relationship between capital flight, labor migration and economic growth of Pakistan. Time series data is used from 1983-2014 for variables like unemployed labor, capital outflow, unemployment and political instability. Different techniques such as unit root test, granger causality test, ordinary least square and two stages least square are used. Granger causality test showed that capital flight and economic growth have bidirectional causality, while labor migration and economic growth showed unidirectional causality. Two stage least square showed that political instability, labor migration, capital flight and unemployment have the negative impact on the economic growth of Pakistan. Political and security situation should be improved for better economic growth

Frequency of depression and anxiety among patients with chronic spontaneous urticaria visiting a tertiary care hospital in Karachi, Pakistan

Objective: To determine the frequency of anxiety and depression among chronic spontaneous urticarial patients presenting at a tertiary care hospital.Methods: The prospective, cross-sectional study was conducted at the Aga Khan University Hospital, Karachi, from February to August 2015, and comprised patients diagnosed with chronic spontaneous urticaria at the dermatology clinic. All the participants were assessed for anxiety and depression using Aga Khan University-Anxiety Depression Scale. Data was collected in face-to-face interview using a structured questionnaire. The association of the condition with different characteristics were calculated after stratification for age, gender, occupation and monthly income. SPSS 19 was used for data analysis..Results: Of the 146 study participants, 84(57.5%) were males and 62(42.5%) were females. The overall mean age was 39±15.6 years. Of the total, 39(26.7%) had depression and anxiety. Depression and anxiety were more frequent among patients with a positive family history of mental disorders (p=0.02).Conclusion: Anxiety and depression were found to be considerably common among chronic spontaneous urticaria patients, with patients having a positive family history for mental illnesses particularly vulnerable

Comparison of pre-treatments to reduce salinity and enhance biomethane yields of Laminaria digitata harvested in different seasons

Pre-treatment can enhance anaerobic digestion of seaweed; however, seasonal variation in the biochemical composition of seaweed has a significant impact on the pre-treatment effect. In this study, various pre-treatments were employed for the brown seaweed Laminaria digitata harvested in March (with high ash content and low carbon to nitrogen (C:N) ratio) and September (with low ash content and high C:N ratio). Washing of L. digitata harvested in March with hot water (defined as 40 °C) removed 54% of the ash and improved the volatile solids (VS) content by 31% leading to an improved biomethane yield of 282 L CH4 kg VS−1. This pre-treatment affected a 16% increase in biodegradability, reduced salt accumulation in the digestate by 54%, and increased specific methane yield per wet weight by 25%. This level of effect was not noted for seaweed harvested in September, when the biodegradability is higher

Evaluation of 222Rn and 226Ra concentrations in cement and limestone of Sheikh Buddin Hill, Pezu, Pakistan using different techniques

Lucky Cement Factory, Pezu is using limestone of Sheikh Buddin Hills as a raw material in cement. Workers of the factory have direct and general public have indirect exposure to radiological hazard due to natural radionuclides present in limestone. To address the radiological hazards, limestone, mixed (limestone+clay) and cement samples were evaluate for concentrations of 222Rn and 226Ra using CR-39, RAD7 and HPGe detectors. Maximum mean values of 222Rn using CR-39 and RAD7 detectors were found 1447 ± 198 and 1416 ± 74 Bq.m−3 in cement samples and minimum were found in 536 ± 122 and 525 ± 45 Bq.m−3 limestone samples, respectively. Maximum mean value of radon exhalation rate of 12.28 ± 1.68 Bq.m−2 h−1 in cement samples was found below the world average value of 57.6 Bq.m−2 h−1. Maximum mean values of 226Ra measured by CR-39 and HPGe detectors were found 24.25 ± 3.35 and 23.6 ± 0.70 Bq.kg−1 in cement samples and minimum were found in 8.98 ± 2.02 and 9.19 ± 0.40 Bq.kg−1 limestone samples, respectively. A positive correlations (R2 = 0.9714) using CR-39 and RAD7 detectors and (R2 = 0.9573) using CR-39 and HPGe detectors were obtained for the concentrations of 222Rn and 226Ra, respectively. Maximum mean value of annual effective dose of 347.78 ± 47.58 µSv.y−1 in cement samples was found below the world average value of 1100 µSv.y−1. © 2019, © 2019 Informa UK Limited, trading as Taylor & Francis Group

Synthesis and Characterization of Na-Zeolites from Textile Waste Ash and Its Application for Removal of Lead (Pb) from Wastewater

Massive production of carcinogenic fly ash waste poses severe threats to water bodies due to its disposal into drains and landfills. Fly ash can be a source of raw materials for the synthesis of adsorbents. Rag fly ash as a new class of raw materials could be a cheap source of Al and Si for the synthesis of Na-zeolites. In this work, NaOH activation, via a prefusion- and postfusion-based hydrothermal strategy, was practiced for the modification of rag fly ash into Na-zeolite. Morphology, surface porosity, chemical composition, functionality, mineral phases, and crystallinity, in conjunction with ion exchangeability of the tailored materials, were evaluated by SEM, ICP-OES, XRF, FTIR, XRD, and cation exchange capacity (CEC) techniques. Rag fly ash and the synthesized Na-zeolites were applied for the removal of Pb (II) from synthetic wastewater by varying the reaction conditions, such as initial metal ion concentration, mass of adsorbent, sorption time, and pH of the reaction medium. It was observed that Na-zeolite materials (1 g/100 mL) effectively removed up to 90–98% of Pb (II) ions from 100 mg/L synthetic solution within 30 min at pH ≈ 8. Freundlich adsorption isotherm favors the multilayer heterogeneous adsorption mechanism for the removal of Pb (II). It is reasonable to conclude that recycling of textile rag fly ash waste into value-added Na-zeolites for the treatment of industrial wastewater could be an emergent move toward achieving sustainable and green remediation