Abstract. Nowadays development of construction in Malaysia has been effect to the increasing of construction waste. Additionally, the production of construction waste from construction projects has given negative impact to the environment especially in illegal dumping activities. The increasing number of illegal dumping activities from construction projects in Malaysia gives a sign that Malaysian construction waste management needs to be concerned. To date, a comprehensive criterion for construction waste management, particularly for a construction project in developing countries is still not clearly defined. Therefore, construction waste management in Malaysia needs further research. The objectives of this paper are to explore illegal dumping activities, and discuss the contributory factors of illegal dumping activities. Hence, this research conducted an interview with expertise in the area of construction waste management in order to scrutinise illegal dumping activities in Malaysia. The data from semistructured interviews were analysed by content analysis. Findings from this research will help to find out the strategies to reduce the illegal dumping activities. The final result also expected to increase the awareness and better solution for reducing illegal dumping activities in construction projects among construction players.

Reactions of CO2 with formation rock may lead to an enhancement in the permeability due to rock dissolution, or damage (reduction in the core permeability) because of the precipitation of reaction products. The reaction is affected by aquifer conditions (pressure, temperature, initial porosity, and permeability), and the injection scheme (injection flow rate, C02:brine volumetric ratio, and the injection time). The effects of temperature, injection flow rate, and injection scheme on the permeability alteration due to CO2 injection into heterogeneous dolomite rock is addressed experimentally in this paper. Twenty coreflood tests were conducted using Silurian dolomite cores. Thirty pore volumes of CO2 and brine were injected in water alternating gas (WAG) scheme under supercritical conditions at temperatures ranging from 21 to 121 °C, and injection rates of 2.0-5.0 cm^l min. Concentrations of Cd^^, Mg'^'^, and Na'^ were measured in the core effluent samples. Permeability alteration was evaluated by measuring the permeability of the cores before and after the experiment. Two sources of damage in permeability were noted in this study: (1) due to precipitation of calcium carbonate, and (2) due to migration of clay minerals present in the core. Temperature and injection scheme don't have a clear impact on the core permeability, A good correlation between the initial and final core permeability was noted, and the ratio of final permeability to the initial permeability is lower for low permeability cores, [

Summary Carbon dioxide (CO2) injection in carbonate formations causes a reduction in the well injectivity caused by precipitation of the reaction products between CO2, rock, and brine. The precipitated material includes sulfate and carbonate scales. The homogeneity of the carbonate rock, in terms of mineralogy and rock structure, is an important factor that affects the behavior of permeability changes during CO2 injection. Limestone rocks that were tested in this study included homogeneous Pink Desert limestone and Austin chalk, which were mainly calcite; heterogeneous Silurian dolomite (composed of 98 wt% carbonate minerals and 2 wt% silicate minerals); and heterogeneous Indiana limestone, which was mainly calcite and had vugs. Experiments were conducted to compare the permeability loss between these rocks during corefloods. CO2 was injected with the water-alternating-gas (WAG) technique. Different brines were examined, including sulfate-bearing seawater and no-sulfate seawater. The experiments were run at a backpressure of 1,300 psi, a temperature of 200°F, and an injection rate of 5 cm3/min. A compositional-simulator tool (CMG-GEM) was used to predict the Carman-Kozeny and power-law exponents on the basis of the experimental results. More damage was observed for heterogeneous rocks compared with the homogeneous cores—the source of damage to permeability for high-permeability cores is the precipitation of reaction products—but for low-permeability cores, capillary forces between CO2 and brine increase the severity of formation damage. The form of the precipitated material changes depending on the core mineralogy and permeability. The simulation study showed that for the cores tested in this study, power-law exponent and Carman–Kozeny exponent between 5 and 6 can be used for the homogeneous carbonate rock to estimate the change in permeability depending on change in porosity, whereas a larger exponent is needed for heterogeneous cores.

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CO 2 will potentially cause formation damage when injected in sandstone formations, due to the precipitation of reaction products that are generated by the reaction between carbonic acid and different clays and feldspars, which often exists in sandstone formations.Several parameters affect these interactions including pressure, temperature, brine composition, CO 2 injection rate, and overall injection scheme. This paper addresses the effect of the temperature and injection scheme on the permeability reduction generated in the sandstone cores due to CO 2 injection. A core flood study was conducted using Berea sandstone cores. CO 2 was injected under supercritical conditions at a pressure of 1,300 psi, and at temperatures ranging from 70 to 250˚F at injection flow rate of 5.0 cm 3 /min. Core effluent samples were collected and the concentrations of calcium, potassium, magnesium, aluminum, iron, and silicon ions were measured. Precipitated material collected in the effluent samples were analyzed using XRD and XRF. Core permeabilities were measured before and after the experiment to evaluate the damage generated.A significant damage, between 35 and 55% loss in core permeability, was observed after CO 2 injection. For shorter WAG injection the damage was higher, decreasing the brine volume injected per cycle the damage was less. At higher temperatures, 200 and 250˚F, more damage was noted than at 70˚F. Two mechanisms of damage were identified: 1) damage occurred due to the precipitation of the reaction products, and 2) damage due to the migration of clay particles, which were attached by the dissolved cementing materials. Bertier, P., Swennen, R., Laenen, B., Lagrou, D., and Dreesen, R. 2006. Experimental identification of CO 2 -water-rock interactions caused by sequestration of CO 2 in Westphalian and Buntsandstein sandstones of the Campine Basin (NE-. 2005. Upscaling geochemical reaction rates using pore-scale network modeling. Advances in Water Resources 29(9):