فهرست مطالب

Environmental Health Science and Engineering - Volume:6 Issue:3, 2009
  • Volume:6 Issue:3, 2009
  • تاریخ انتشار: 1388/05/11
  • تعداد عناوین: 10
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  • N. W. Chan Page 143
    Water is one of the central issues in the 21st century in Malaysia. Of all the issues associated with water management, governance is considered of primary importance. This paper examines water governance in Malaysia and concludes that it is successful in the sense that water is served to more than 95 % of the population, water tariffs are some of the cheapest in the world, the poor is not denied access, and water supply is 24 hours per day. However, there are many areas that need improvement to achieve better governance in water management. One is to improve Government-controlled water departments by ensuring their workers are well-trained and committed to excellence, public service and integrity instead of the usual laid-back government-servant mentality. Another is to ensure politicians do not interfere in the water sector. Currently, it is widely believed that many water companies are linked to powerful politicians, making the awarding of contracts, tariffs and other management aspects non-transparent and ineffective. Ideally, politicians that govern should act on the professional advice of the water managers and not the other way around. Another area of water governance that needs to be intensified is the war against corruption. In the water sector, there should also be an all-out war on corruption at all levels of governance, in both the public and private sectors. Government should make all contracts in the water sector awarded through open tender with public consultation to ensure professionalism, fairness, transparency, accountability and good governance. Equally, all contracts and other relevant documents drawn up between the government and private companies should not be "classified" but instead be public documents available to the public for discussion, review and improvement. Another area to ensure better governance is for the government to engage and actively involved all stakeholders in the water sector, especially civil society and NGOs. Finally, the Federal Government should reconsider its plans to centralize the water sector by taking it over from State Governments. This is because, centralization would be contradictory towards involvement of all stakeholders and also pose problems to many states that had already privatized the water sector. Finally, governance of the water sector should be based on Integrated Water Resources Management which is the logical way forward in ensuring sustainable development.
    Keywords: Water resources management, Water governance, Privatisation, NGO, Civil society
  • H. Movahedyan, A. M. Seid Mohammadi, A. Assadi Page 153
    of ammonium from aqueous solutions. The research was carried out in continuous system. The characteristics of graded clinoptilolite from Semnan (one of the central provinces in Iran) mines were determined and then regeneration tests were done by contacting of 1 N NaCl solution with given weights of ammonium saturated zeolite. Then the brine of column was transferred to the air stripping column for regeneration. The pH of brine solution before entrance to a stripping column was increased to 11. Air stripped ammonia from the brine was converted to the ammonium ion by using acid scrubber. The outlet effluent from stripping column was collected for reuse. The results showed that the cation exchange capacities were 17.31 to 18.38 mg NH4 of zeolite weight. Regeneration efficiency of zeolite by NaCl solution and air stripping was in the range of 92%-97% under various operational conditions. However, the efficiency of acid absorption of released ammonia in stripping process was 55% with a major rejection of the surplus ammonia to the atmosphere. It could be concluded that the method studied may be considered as an advanced and supplementary process for treating effluents of aqueous solution and fishponds in existing treatment plants.
    Keywords: Degradation rate, p, chlorophenol, Ultraviolet/H2O2, Microwave/H2O2, Microwave irradiation
  • N. Khellaf, M. Zerdaoui Page 161
    To assess the tolerance and effect of heavy metals pollution on the duckweed Lemna minor, the aquatic plants were exposed to different concentrations of copper (Cu), nickel (Ni), cadmium (Cd) and zinc (Zn) in a quarter Coïc and Lessaint solution at pH = 6.1 (± 0.1) and under a daily regime of 16 h light (101 μmol/m2.s1). Copper at 0.2 mg/L and nickel at 0.5 mg/L promoted the growth of Lemna fronds. At higher concentrations, Cu and Ni inhibited the growth of duckweed; the EC50 (concentration causing 50% inhibition) were 0.47 mg/L for Cu and 1.29 mg/L for Ni. Cadmium and zinc decreased by 50% the growth of fronds when the medium contained respectively 0.64 and 5.64 mg/L (EC50). Duckweed tolerated Cu, Ni, Cd and Zn at concentrations of 0.4, 3.0, 0.4 and 15.0 mg/L respectively without showing any visible signs of toxicity (chlorosis, frond disconnection and necrosis). On the basis of visible symptoms and the EC50 values, the toxicity of the metals on Lemna. minor was in decreasing order of damage: Cu > Cd > Ni > Zn. It was concluded that the duckweed Lemna. minor is very sensitive to copper and cadmium pollution.
    Keywords: Growth, Lemna. minor, Heavy metal, Tolerance, Toxicity
  • A. R. Rahmani, M. T. Samadi, H. R. Ehsani Page 167
    The purpose of this study was to regenerate clinoptilolite natural zeolite by air stripping followed by removal of ammonium from aqueous solutions. The research was carried out in continuous system. The characteristics of graded clinoptilolite from Semnan (one of the central provinces in Iran) mines were determined and then regeneration tests were done by contacting of 1 N NaCl solution with given weights of ammonium saturated zeolite. Then the brine of column was transferred to the air stripping column for regeneration. The pH of brine solution before entrance to a stripping column was increased to 11. Air stripped ammonia from the brine was converted to the ammonium ion by using acid scrubber. The outlet effluent from stripping column was collected for reuse. The results showed that the cation exchange capacities were 17.31 to 18.38 mg NH4 of zeolite weight. Regeneration efficiency of zeolite by NaCl solution and air stripping was in the range of 92%-97% under various operational conditions. However, the efficiency of acid absorption of released ammonia in stripping process was 55% with a major rejection of the surplus ammonia to the atmosphere. It could be concluded that the method studied may be considered as an advanced and supplementary process for treating effluents of aqueous solution and fishponds in existing treatment plants.
    Keywords: Ammonium removal, Ion exchange, Clinoptilolite natural zeolite, Air stripping, Regeneration
  • T. Ch. Ogwueleka Page 173
    Municipal solid waste management has emerged as one of the greatest challenges facing environmental protection agencies in developing countries. This study presents the current solid waste management practices and problems in Nigeria. Solid waste management is characterized by inefficient collection methods, insufficient coverage of the collection system and improper disposal. The waste density ranged from 280 to 370 kg/m3 and the waste generation rates ranged from 0.44 to 0.66 kg/capita/day. The common constraints faced environmental agencies include lack of institutional arrangement, insufficient financial resources, absence of bylaws and standards, inflexible work schedules, insufficient information on quantity and composition of waste, and inappropriate technology. The study suggested study of institutional, political, social, financial, economic and technical aspects of municipal solid waste management in order to achieve sustainable and effective solid waste management in Nigeria.
    Keywords: Waste disposal, Waste Collection, Municipal solid waste, Nigeria, Recycling, Waste Management
  • R. Golmohammadi, M. Abbaspour, P. Nassiri, H. Mahjub Page 181
    Noise is one of the most important sources of pollution in the metropolitan areas. The recognition of road traffic noise as one of the main sources of environmental pollution has led to develop models that enable us to predict noise level from fundamental variables. Traffic noise prediction models are required as aids in the design of roads and sometimes in the assessment of existing, or envisaged changes in, traffic noise conditions. The purpose of this study was to design a prediction road traffic noise model from traffic variables and conditions of transportation in Iran.
    This paper is the result of a research conducted in the city of Hamadan with the ultimate objective of setting up a traffic noise model based on the traffic conditions of Iranian cities. Noise levels and other variables have been measured in 282 samples to develop a statistical regression model based on A-weighted equivalent noise level for Iranian road condition. The results revealed that the average LAeq in all stations was 69.04± 4.25 dB(A), the average speed of vehicles was 44.57±11.46 km/h and average traffic load was 1231.9 ± 910.2 V/h.
    The developed model has seven explanatory entrance variables in order to achieve a high regression coefficient (R2=0.901). Comparing means of predicted and measuring equivalent sound pressure level (LAeq) showed small difference less than -0.42 dB(A) and -0.77 dB(A) for Tehran and Hamadan cities, respectively. The suggested road traffic noise model can be effectively used as a decision support tool for predicting equivalent sound pressure level index in the cities of Iran.
    Keywords: Noise, Noise pollution, Traffic noise, Environment, Prediction model, Modeling
  • A. K. Pathak, K. S. Verma Page 187
    Urban and rural vegetable markets of India characterized by mass activity with a little sanitary measure are responsible for generation of higher quantity of aerosols containing biotic and abiotic components. The aerosols generated in due course of mechanical disturbance, contain many organic compounds enable to sensitize vital respiratory organs of local inhabitants. Inhalation of airborne microorganisms can expose workers to risks from infection, toxicosis and allergy. The presence of non-spore forming gram-negative bacteria in air due to the mechanical areosolization indicates higher rate of dissemination of pollutants in these occupation associated areas. The present aero-bacteriological investigation included enumeration, identification and numerical analysis of different types of culturable airborne bacteria with inhalable fraction of gram-negative bacteria in the vegetable market of the city of Jabalpur, in order to measure the degree of aerobiopollution for this environment. The aero-bacteriological sampling has been done fortnightly for a period of one year. Samples were cultured based on standard methods. The survey revealed that in this type of atmosphere, environmental factors were responsible for the persistence of airborne bacteria with variable effects. The major contributors for aerosol generation were other mechanical activities, since this site is classified under human activity-enriched and highly trafficked site. The bioload of this atmosphere was recorded as high as 2.9 x 103 bacterial carrying particles per cubic meter during winter, dominated by both inhalable and non inhalable fractions of gram-negative bacteria. In summer, soil-borne bacteria were reported dominant in the air. High humidity and low temperature were the major factors for dissemination and distribution of gram-negative bacilli. A regression model with upto 43% variance was prepared in order to predict the bioload for this atmosphere in relation to meteorological parameters.
    Keywords: Aerosolization, Aero, bacteriological investigation, Gram, negative bacteria, Vegetable market
  • G. K. Nagda, V. S. Ghole Page 195
    Solid wastes from agro-industrial operations can be recycled as non-conventional adsorbents if they are inert and harmless and reduce the cost of wastewater treatment. Tendu leaf Diospyros melanoxylon is the second largest forest product in India after timber and is exclusively used in making local cigarette called Bidi. Waste leaf cutting remaining after making cigarette was used in present study as a biosorbent for the removal of Congo red dye from aqueous solution. It was treated with hydrogen peroxide to obtain biosorbent with increased adsorption capacity. Batch type experiments were conducted to study the influence of different parameters such as pH, initial dye concentration and dosage of adsorbent on biosorption evaluated. The adsorption occured very fast initially and attains equilibrium within 60 min at pH= 6.2 and the equilibrium attained faster after hydrogen peroxide modification. Kinetic studies showed that the biosorption of Congo red on tendu waste followed pseudo-second-order rate equation. The data fitted well to Langmuir and Freundlich isotherm models. Comparison was done on the extent of biosorption between untreated and treated forms of the tendu waste. The maximum adsorption capacity for untreated tendu waste was found to be 46.95 mg/g, which was enhanced by 2.8 times after hydrogen peroxide treatment and was found to be 134.4 mg/g. The adsorption process was in conformity with Freundlich and Langmuir isotherms for Congo red adsorption from aqueous solution. The study demonstrated use of milder chemical treatment of tendu waste to obtain a biosorbent with enhanced dye removal capacity.
    Keywords: Tendu waste, Diospyros melanoxylon, Congo red, Biosorption, Chemical modification
  • S. Sivakumar, H. Kasthuri, P. Senthilkumar, C. V. Subbhuraam, Y. C. Song Page 201
    Parthenium plants and neem leaves were composted using the epigeic earthworm, Eisenia fetida (worm-worked compost) to study the growth and reproductive indices of earthworm involved in the process of composting. Similarly, parthenium plants and neem leaves were composted without worms (worm-unworked compost). Efficacy of the resulting composts in supporting the growth of plant was tested with the germination and growth of Vigna radiate seedlings. The results showed that higher parthenium amendment significantly reduced the growth and reproduction of Eisenia fetida compared with control. The two-way ANOVA results showed a significant difference in the growth rate of worms when exposed to different amended concentrations of parthenium plants and neem leaves at different durations as fixed factors. The following compost parameters were not significantly different when compared with control: pH, nitrogen, phosphorus, iron for parthenium worm-worked compost; nitrogen, phosphorus, magnesium, iron, organic carbon and carbon/nitrogen ratio for neem worm-worked compost; nitrogen, phosphorus and organic carbon for parthenium worm-unworked compost and pH, nitrogen, phosphorus, zinc and carbon/nitrogen ratio for neem worm-unworked compost. Between parthenium plant composts and neem leaves composts, significant differences were not observed in any of the plant biometric parameters. The results obtained from the present study indicated that the parthenium composting at low amendments with cow dung may help its eradication for better utilization.
    Keywords: Eisenia fetida, Neem leaves, Parthenium plant, Vermicompost
  • E. O. Longe, O. O. Longe, E. F. Ukpebor Page 201
    The current work examined the structure of household waste management system, collection and disposal within the context of a wider research on integrated solid waste management in households. A sample of 30 households from eleven selected residential areas with a focus group of 60 respondents in Ojo Local Government Area, Lagos State, Nigeria was used. The selected residential areas were divided into high, middle and low socio-economic strata. The research examined a range of environmental behaviours, attitude and perception of respondents on household solid waste management. The results established waste management behaviours among the respondents on solid waste management system, services, patronage of services and cost recovery methods. Public opinion and perception on solid waste management system is characterized with irregularity and inefficient collection system; with poor monitoring of the private waste service providers by the local authority. Willingness to pay for waste management services provided by the private service providers, the Private Sector Participation operators is higher among the middle and high income socio-economic groups than in the low income group. However, with the application of sustainable environmental education greater success ratio could be achieved. Level of patronage of solid waste management services is high across the three socio-economic groups but patronage is shared among the two operating service providers (formal and informal). The Private Sector Participation has the highest patronage level with 64.6% severity index while the informal sector (Cart pushers) have only 48.7% severity index both percentages translate to the agreed and neutral perception opinion ranges respectively. The paper advocates for improved solid waste management system through proper monitoring of the services of the Private Sector Participation operators by the Local Government Area for improved service efficiency. Finally the research suggests appropriate lines of action on sustainability of a private sector driven solid waste management scheme in the Local Government Area and in Lagos State in general.
    Keywords: Household waste, Solid waste, Service provider, Perception, Attitude, Severity index