Electrocoagulation in removal of cod and heavy metal in leachate from Pulau Burung landfill site (PBLS), Penang

In solid waste management, landfilling is the most common methods for the disposal of municipal solid wastes in many countries around the world. Leachate is one of the major environmental concerns associated with landfilling which may either exist as aqueous effluent in the landfill or created after rainwater mixes with the chemical waste in the landfill. Landfill leachate is characterized as high-strength wastewater exhibiting acute and chronic toxicity (Deng and Englehardt, 2006). Leachates has high concentration of COD (Cossu et al., 1998) and heavy metals.The commonly found elements in high concentration includes iron, manganese, zinc, chromium, lead, copper and cadmium (Aziz et al., 2004). This contaminant leads to serious pollution within medium in contact with the waste especially on soil (Tsai et al,. 1996) and groundwater aquifers (Contreras et al., 2009) as well as adjacent surface water (Atmaca, 2009). Electrocoagulation is an electrochemical wastewater treatment technology that has been successfully employed in removing metals, suspended particles, clay minerals, organic dyes, and oil and greases from a variety of industrial effluents (Mollah et al., 2004). According to Aziz et al., (2007), Pulau Burung Landfill Site (PBLS) is situated within Byram Forest Reserve in Penang, Malaysia. This landfill has been developed as a sanitary landfill Level II by establishing a controlled tipping technique in 1991. It was further upgraded to a sanitary landfill level III by employing controlled tipping with leachate recirculation in 2001. Based on the case study by Syarifah and Abdul Yamin (2009), the real average value of tonnage at this sanitary landfill now is about 2 200 tonnes per day. Roughly, the disposal wastes are divided into two categories which are domestic waste (60%) and industrial waste (40%)

The hydrostratigraphic and groundwater flow modeling of Mukah coal mining affected areas

The hydrostratigraphic and groundwater flow information within the vicinity of Mukah Coal field is important to provide a guideline in protecting the groundwater resources. The delineation of the regional aquifer–aquitard framework requires precise evaluation of the hydrostratigraphic controls and temporal patterns of groundwater flow of the study area. Possible natural contaminants include trace elements such as arsenic and selenium, radionuclides such as radon, and high concentrations of commonly occurring dissolved constituents are the possibly wash out together with spillage of removed overburden and eventually enter the groundwater aquifer. The hydrostratigrahic interpretation and the groundwater flow modeling are supported by Lithologic data analysis, wireline logging, resistivity imaging lines, and from the Ground Penetrating radar runs within the study area. The lithologic logs were obtained from 26 drill holes including drill holes for groundwater exploration and drill holes for coal exploration within the study area. A total of 8 Wirelines run for these drill also used to confirm the lithologic logs of the drill holes. Both resistivity imaging (6 runs) and Ground Penetrating Radar (6 runs) methods were used to evaluate further lithological sections of the study area. The study area is dominated by various aquifer systems, which are mostly unconfined. In several localities, this main aquifer has been locally divided into multiple layers by the presence of discontinuous aquitards (with a lateral extent of one to a few kilometers). Generally, the direction of groundwater flow is towards the central part of Mukah Coal Mining area

Effects of ultrasonic irradiation on landfill leachate under different operating conditions.

One of the interesting and promising methods for removal of Total Organic Carbon (TOC) present in the landfill leachate is by the application of ultrasonic waves. The aim of this study is to evaluate the reduction efficiency of TOC by ultrasonic irradiation at different operating parameters, namely, the applied ultrasonic power, pH, initial concentration, presence of saturating gas and addition of catalyst (FeSO4) under sonication (20 kHz). Ultrasound can degrade different kinds of pollutants by combining destruction of the target compounds by free radical reaction and thermal cleavage. Overall, the highest reduction of TOC of 47.15% is achieved at the initial concentration, without addition of FeSO4, at pH of 7.4, temperature of 30 C, the ultrasonic frequency of 20 kHz and power density of 0.188 W/cm3. The results indicate that the ultrasonic alone is not capable of mineralizing the TOC in the landfill leachate due to the high strength and molecular weight of pollutants in the leachate

Electrical resistivity imaging and bedrock elevation in UPM, Serdang, Malaysia

Electrical resistivity imaging surveys have been conducted in order to locate, delineate subsurface water resource and estimate its reserve. The resistivity imaging surveys carried out basically measures and maps the resistivity of subsurface materials. A 2-D geoelectrical resistivity technique was used. Resistivity measurement was carried out using an ABEM SAS 4000 terrameter with electrode selector system. A Wenner electrode configuration was employed. The field survey was conducted along four profiles providing continuous coverage. Colour-modulated sections of resistivity versus depth were plotted for all lines, giving an approximate image of the subsurface structure. The results showed that the layers associated with the resistivities between 30μm and 10000μm and are located at a depth varying from 8 to 36m

Effects of ultrasonic irradiation on concentration of chemical oxygen demand in Landfill Leachate.

Landfilling for the disposal of municipal solid wastes continues to be widely accepted and used due to its economic advantages, but it could be a potential source of surface and ground water contamination. Therefore, the study was conducted to investigate the efficiency of ultrasonic irradiation for reducing the Chemical Oxygen Demand (COD) from one of the landfill sites in Malaysia. Several operating conditions, such as power density (24 to 188 W/L), pH (2 to 11), dilution factor (1:9, 1:1 and 9:1) and addition of different amount of Ferrous sulfate (FeSO4) (1.0 to 5.0 mmol/L) were tested concerning their effect on COD reduction. Results indicated that the best irradiation conditions were enhanced at increased power density of 188 W/L, pH 7.4, initial concentration and without addition of catalysts with a percentage reduction of 95.55%. This suggested that the removal of COD in landfill leachate was mainly contributed by higher concentration of hydroxyl radical which leads to higher reduction of organic matters

Effect of ultrasonic irradiation on COD and TSS in raw rubber mill effluent.

The problem of inadequate clean water is expected to grow worse in the next coming decades. Finding new ways are important to solve this problem. Sonochemical oxidation is one of the advanced oxidation methods in the area of wastewater.Its simple application combined with the production of degradable by-product make the system attractive as an alternative treatment process for difficult- to-treat waste such as rubber effluent. Organic compounds in liquid exposed to acoustic cavitation may act differently according to the physical and chemical properties of the effluent. Batch experiments of sonication were carried out to evaluate the effectiveness of the ultrasonic irradiation of organic compounds in raw rubber mill effluent at different power densities. The degradability of the effluent was assessed based on the changes in the value of COD and TSS values exposed to ultrasonic energy or power density ranging from 0.024W/cm to 0.188W/cm. The highest COD and TSS reduction values were 91% and 76%, respectively was obtained at power density of 0.024W/cm3 after 90 min irradiation. The study shows the optimum conditions for maximum efficacy of the ultrasonic reactors

Effects of ultrasonic irradiation on raw rubber mill effluent.

Ultrasonic irradiation, an interesting and promising application, is useful as a new technique for degradation of organic compounds. The effects of ultrasonic irradiation in raw rubber wastewater is investigated at different operating conditions, namely, power density, varying pH, and the presence of saturating gas and catalysts. Ultrasound at 20 kHz frequency is used in irradiation of samples. Reactions are carried out at 30 C, the maximum ultrasonic irradiation time being 2 h. Results show that the presence of saturating gas with ultrasonic irradiation has the highest Chemical Oxygen Demand (COD) percentage reduction (61.83%), when compared to other operating conditions having the range 30.87-51.30%. Sonochemistry is associated with cavitation bubbles. These are ascribed to the cavitation effects of ultrasound, producing extremely high temperature and pressure, which allow the formation of reactive radicals. Therefore, the selection of treatment condition is very important

Weathering product of granite as a possible source of strategic mineral

Several soil samples and granite bedrock samples from Cameron Highlands were analyzed for its elemental concentration using instrumental neutron activation analysis. A total of 34 elements were identified and their concentrations were determined in a single analytical session. Enrichment factor of elemental concentration in the top soil were computed. The findings indicate certain elements were enriched that may facilitates economic beneficiation