The perception of households about solid waste management issues in Malaysia

With the aim being to have an integrated and efficient management system, Malaysia is currently facing a remarkable waste issue with a massive increase in waste generated per day. This study collected 400 survey responses to assess the satisfaction and awareness of households about various issues of solid waste management. This study revealed that the majority of the respondents were satisfied with their waste management services. However, there was concern about providing a more diverse waste management facility. This study found a strong positive relationship between age and waste reduction behaviours. The majority of the respondents agreed that their lifestyle affected waste minimisation. Almost half of the respondents indicated that they lacked knowledge to practise waste sorting. Age and education were positively correlated to reuse and recycling behaviours. Overall, a holistic waste management education is vital for Malaysia to build an efficient waste management system.     

Regeneration performance of spent granular activated carbon for tertiary treatment of dyeing wastewater by Fenton reagent and hydrogen peroxide

Journal of Material Cycles and Waste Management - The efficacy of Fenton reagent and hydrogen peroxide for the regeneration of saturated granular activated carbon with biological effluent of dyeing...     

沸石负载Fe_3O_4光催化氧化去除水中苯酚

为了对水中苯酚的去除进行研究,通过离子交换法及液相沉积法在天然沸石上负载Fe3O4制备出一种具有较高反应活性的复合催化剂,采用X-射线衍射仪(XRD)、扫描电镜(SEM)等仪器对其结构和形貌进行表征,并利用复合催化剂进行非均相UV/Fenton反应处理模拟苯酚废水,考察不同因素对苯酚降解效果的影响。实验结果表明,在催化剂投加量为0.4 g/L,H2O2投加量为二分之一理论投加量,pH为3~10且室温的条件下,处理100 mg/L的模拟苯酚废水,60 min之内苯酚去除率可达90%以上。通过对催化剂的稳定性研究,发现经5次循环使用后,苯酚去除率均可保持在90%以上,具有良好的循环使用性能。     

生活垃圾堆肥浸提液组成及其演化规律

堆肥浸提液与渗滤液组成相似,研究生活垃圾堆肥浸提液组成与演化特征可以为堆肥过程污染控制和堆肥质量改善提供科学依据。通过基本理化指标和三维荧光光谱分析,研究了生活垃圾堆肥浸提液的组成和转化特性。结果显示,在堆肥一次和二次发酵过程中,浸提液p H由5.43上升至9.24,无机阴离子无显著变化,电导率(EC)稳定在7.50m S/cm上下波动,ORP为正值,总氮从611.08 mg/L下降至177.43 mg/L,NH+4-N和NO-3-N浓度变化不明显,NO-2-N从未检出到后期达10.28 mg/L,有机氮从246.64 mg/L下降至172.52 mg/L。溶解性有有机物含量(DOC)从7 419.00 mg/L降至5 569.00 mg/L,其中的有机物发生降解和转化,生成胡敏酸和富里酸等物质。浸提液中重金属Fe、Cd、Cu、Zn、Cr、Mn、Ni和As浓度升高。通过研究发现,在堆肥中添加木屑等填料可以降低浸提液中NH+4-N的浓度,具有除臭作用,同时对p H值、EC和ORP均有调节作用,能提高堆肥的土地可利用性。     

外循环式UASB反应器处理槟榔废水

在中温（35±2℃）条件下,利用外循环式UASB反应器处理中高有机浓度的槟榔加工废水,并着重探讨了水力停留时间（HRT）对厌氧消化的影响。研究表明,当反应器稳定运行,水力停留时间为1 d,进水COD浓度5 000 mg/L左右,容积负荷在2.53-5.25 kg COD/（m3·d）时,COD去除率在38%以上,出水COD〈3 000 mg/L,平均产气率为0.41 m3/kg COD;若水力停留时间延长至4 d,容积负荷为1.26-1.30 kg COD/（m3·d）,COD去除率可以达到79%,出水COD〈1 200 mg/L,出水可生化性下降,BOD5/COD平均为0.28,实验取得了良好的处理效果,为利用厌氧技术处理槟榔加工废水提供了设计依据。     

超声强化活性污泥法处理含芳香族硝基化合物废水

采用低强度超声波强化活性污泥法处理经超声空化预处理后的含芳香族硝基化合物废水,考察了超声波功率、频率、作用时间等因素对处理效果的影响,并分析了超声强化活性污泥法的作用机理。实验结果表明,当超声波功率为10w、频率为25kHz、辐照时间为15min、作用周期为12h时,对去除废水中对硝基苯胺、硝基苯与COD的强化效果达到最佳,比未经超声强化的对照组分别高出38．6％、40．4％和21．9％。     

Mercury in dental amalgam: Are our health care workers at risk?

Dental amalgam in fillings exposes workers to mercury. The exposure to mercury was investigated among 1871 dental health care workers. The aim of the study was to evaluate the risk of mercury exposure among dental compared to nondental health care workers and to determine other risk factors for mercury exposure. Respondents answered questionnaires to obtain demographic, personal, professional, and workplace information and were examined for their own amalgam fillings. Chronic mercury exposure was assessed through urinary mercury levels. In total, 1409 dental and 462 nondental health care workers participated in the study. Median urine mercury levels for dental and nondental health care workers were 2.75 μg/L (interquartile range [IQR] = 3.0175) and 2.66 μg/L (IQR = 3.04) respectively. For mercury exposure, there were no significant risk factor found among the workers involved within the dental care. The Mann–Whitney test showed that urine mercury levels were significantly different between respondents who eat seafood more than 5 times per week compared to those who eat it less frequently or not at all (p = 0.003). The urinary mercury levels indicated significant difference between dental workers in their practice using squeeze cloths (Mann–Whitney test, p = 0.03). Multiple logistic regression showed that only the usage of cosmetic products that might contain mercury was found to be significantly associated with the urinary mercury levels (odds ratio [OR] = 15.237; CI: 3.612–64.276). Therefore, mean urinary mercury levels of health care workers were low. Exposure to dental amalgam is not associated with high mercury exposure. However, usage of cosmetic products containing mercury and high seafood consumption may lead to the increase of exposure to mercury.

Implications: Exposure to the high levels of mercury from dental amalgam can lead to serious health effects among the dental health care workers. Nationwide chronic mercury exposure among dental personnel was assessed through urinary mercury levels. Findings suggest low urinary mercury levels of these health care workers. Exposure to dental amalgam is not associated with high mercury exposure. However, the usage of cosmetic products containing mercury and high seafood consumption may lead to the increase of exposure to mercury.     

Multiple regression analysis in modeling of columnar ozone in Peninsular Malaysia

This study aimed to predict monthly columnar ozone (O₃) in Peninsular Malaysia by using data on the concentration of environmental pollutants. Data (2003–2008) on five atmospheric pollutant gases (CO₂, O₃, CH₄, NO₂, and H₂O vapor) retrieved from the satellite Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY) were employed to develop a model that predicts columnar ozone through multiple linear regression. In the entire period, the pollutants were highly correlated (R?=?0.811 for the southwest monsoon, R?=?0.803 for the northeast monsoon) with predicted columnar ozone. The results of the validation of columnar ozone with column ozone from SCIAMACHY showed a high correlation coefficient (R?=?0.752–0.802), indicating the model’s accuracy and efficiency. Statistical analysis was utilized to determine the effects of each atmospheric pollutant on columnar ozone. A model that can retrieve columnar ozone in Peninsular Malaysia was developed to provide air quality information. These results are encouraging and accurate and can be used in early warning of the population to comply with air quality standards.     

A contemporary landscape of air pollution and greenhouse gas emissions leads to inevitable phenomena of low birthweight

The objective of the study is to empirically examine the air pollution, greenhouse gas (GHG) emissions and low birth weight in Pakistan through the cointegration and error correction model over a 36-year time period, i.e., between 1975 and 2012. The study employed the Johansen cointegration technique to estimate the long-run relationship between the variables, while an error correction model was used to determine the short-run dynamics of the system. The study was limited to the following variables, including carbon dioxide emissions, methane emissions, nitrous oxide emissions, GHG emissions, and low birth weight in order to manage robust data analysis. The results reveal that air pollution and GHG emissions significantly affects the low birth weight in Pakistan. In the long run, carbon dioxide emissions act as a strong contributor for low birth weight, as the coefficient value indicates there is a more elastic relationship (i.e., ?1.214, p?p?p?相似文献   

生物强化技术应急处理苯胺泄漏事故

为考察生物强化技术用于苯胺水污染事故应急处理的可行性,以化工园区苯胺泄漏事故为场景,采用高效苯胺降解菌AN-P1强化序批式活性污泥法(SBR),应急处理100～500 mg/L苯胺废水。结果表明,生物强化系统应急处理500 mg/L以下苯胺废水,启动时间约3～4周期(2 d),稳定运行后对苯胺的去除率在96.3%以上,化学需氧量(COD)的去除率在81.3%以上;曝气量(溶解氧)是影响降解的制约因素,其最适曝气量为0.5 m3/h。对处理系统中微生物超氧化物歧化酶(SOD)检测表明,强化系统SOD被诱导产生,对照系统中SOD被抑制,强化系统SOD酶活是对照系统的468倍,表明强化系统可有效消除苯胺降解产生的超氧阴离子自由基的氧化压力。