Noor Zalina Mahmood

Application of TOPSIS and VIKOR improved versions in a multi criteria decision analysis to develop an optimized municipal solid waste management model

Selecting a suitable Multi Criteria Decision Making (MCDM) method is a crucial stage to establish a Solid Waste Management (SWM) system. Main objective of the current study is to demonstrate and evaluate a proposed method using Multiple Criteria Decision Making methods (MCDM). An improved version of Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) applied to obtain the best municipal solid waste management method by comparing and ranking the scenarios. Applying this method in order to rank treatment methods is introduced as one contribution of the study. Besides, Viekriterijumsko Kompromisno Rangiranje (VIKOR) compromise solution method applied for sensitivity analyses. The proposed method can assist urban decision makers in prioritizing and selecting an optimized Municipal Solid Waste (MSW) treatment system. Besides, a logical and systematic scientific method was proposed to guide an appropriate decision-making. A modified TOPSIS methodology as a superior to existing methods for first time was applied for MSW problems. Applying this method in order to rank treatment methods is introduced as one contribution of the study. Next, 11 scenarios of MSW treatment methods are defined and compared environmentally and economically based on the waste management conditions. Results show that integrating a sanitary landfill (18.1%), RDF (3.1%), composting (2%), anaerobic digestion (40.4%), and recycling (36.4%) was an optimized model of integrated waste management. An applied decision-making structure provides the opportunity for optimum decision-making. Therefore, the mix of recycling and anaerobic digestion and a sanitary landfill with Electricity Production (EP) are the preferred options for MSW management.

Energy audit and prospective energy conservation - Studies at residential college buildings in a tropical region

Purpose – The purpose of this paper is to present the efficiency of electricity use and potential of electricity reduction at 12 residential colleges located at University of Malaya Campus, Kuala Lumpur.Design/methodology/approach – The work presented applies an energy audit when energy consumption data were collected and analysed for a five‐year period. The total savings of electricity used at residential colleges were identified through the difference between average total energy use in a year (kWh) and minimum electricity usage.Findings – The study finds that residential colleges with special features of building layout and arrangement performed better with regard to electricity consumption due to the prior groups superior utilisation of day lighting and natural ventilation. The floor area of the rooms, volume, density, enclosure and facade design, including window design, window area, and window‐to‐wall ratio also influenced the total electricity usage of the residential college buildings. Also, thro...

Factors that Contribute to the Generation of Construction Waste at Sites

Construction industry in Malaysia is growing rapidly with high demand due to vast development and urbanization. Therefore, many commercial and residential buildings are being developed. The increasing number of construction projects in Malaysia will indirectly contribute to the increase of construction waste generation. Thus, waste minimization is an important area of concern in the implementation of the construction waste management in the construction industry of Malaysia. Data collection and observations was conducted at three construction sites which adopt different type of method with different type of building and size of project in Klang Valley. The calculation of the construction waste index generated at these sites is adopted from Poon et al., (2001). Result showed that construction method, size of projects (GFA), type of building, storage method system, human error and technical problem can affect the amount of waste index (debris) and amount of wastage level generated at construction sites. Therefore waste index and wastage level can be used as operational an indicator for waste minimization of the construction activities.

Inclusion of human errors assessment in failure frequency analysis - A case study for the transportation of ammonia by rail in Malaysia

Risk is defined as the probability of a specific adverse event occurring within a specific period, while Quantitative risk assessment (QRA) is the development of a quantitative estimate of risk based on engineering evaluation and mathematical techniques by combining estimate of incident consequences and frequencies. In view of the increase in the use of railways as the mode of transportation for hazardous materials throughout the world, the associated risk analysis should be taken into concern. In this study, the failure frequency of the transportation of ammonia from the Petronas fertilizers Kedah (PFK) plant in Gurun (Northern part of Peninsular Malaysia), to the Chemical Company Malaysia (CCM) fertilizers facilities in Port Klang (South‐western part of Peninsular Malaysia) was evaluated by incorporating the human error assessment. The study highlighted the importance of human error contributions in the failure frequency analysis and its impact on the selected failure scenarios. Besides, it also shows that the application of the human error assessment and reduction technique (HEART), which is a useful human reliability analysis tool, should be used in parallel with the fuzzy arithmetic approach to reduce the uncertainties involved in the estimation of human error probabilities, and hence, to reduce the likelihood of incorrect risks estimates being assessed. The results suggested that the commonly applied approach in quantitative risk assessments, which only consider equipment failures in the failure frequency estimations, are clearly an underestimate of the potential causes of failures leading to hazardous material releases, and hence, the calculated risks based do not reflect the actual risks.

Treatment of Landfill Leachate Using Ganoderma Australe Mycelia Immobilized on Ecomat

Biological processes have been proven to be efficient in treating landfill leachates. In this study, treatment of landfill leachate by Ecomat-immobilized mycelia of Ganoderma australe packed in a column was investigated. Continuous recycling of leachate at a constant flow (20 ml/min) was operated for 10 cycles to facilitate biological reactions. Diluted leachate (50%) and raw leachate (100%) were tested for comparison of efficiency of treatment. The results showed that biological oxygen demand (BOD 5 ) was not removed for diluted leachate and a slight removal of 0.14 and 1.72% for raw leachate after cycles 4 and 10, respectively. Chemical oxygen demand (COD) removal occurred after each cycle with diluted leachate demonstrating higher removal compared to raw leachate. The highest percentage of COD removal of 51.62% for diluted leachate and 22.79% for raw leachate were achieved after the tenth cycle. Ecomat-immobilized mycelium of Ganoderma australe could also reduce ammoniacal nitrogen (NH 3 -N) exhibiting highest reduction of 45.95% and 30.90% after cycle 8 for diluted and raw leachate, respectively. These findings suggested that a white rot fungus, G. australe has the ability to be considered as potential candidate in landfill leachate treatment.

Waste quantification models for estimation of construction and demolition waste generation: a review

Quantification is crucial for construction and demolition waste management. Accurate estimation can be satisfied by developing waste quantification model that is applicable for regional or nation-wide C&D waste generation. This paper presents a review on quantification models for C&D waste from literatures and how they correlate. Most studies combine the empirical waste assessment data or waste generation factor obtained in the field with area of activity level extracted from national statistical database from their respective countries, which provides annual data on sector activities. National or regional estimates provide general figures and forecasts for annual C&D waste generation. Studies found that waste generation factor will differs according to locations. Since volume and characteristic of waste are crucial for waste quantification, quantitative data record from waste audit findings could benefit the authorities for the annual estimates. National C&D waste reduction plan should start from well-established waste minimisation plan at project sites.

Quantification Methods for Construction Waste Generation at Construction Sites: A Review

Estimation of construction and demolition (C&D) waste amount is crucial for implementing waste minimization program. Estimation of C&D waste amount generated is a mean in assessing the potential for waste reduction. Thus, a better understanding of C&D waste generation in terms of causes and sources can be achieved. The aim of this paper is to conduct a review on available construction waste quantification methods from previous studies, which have been utilized in certain countries, while attempting to choose the most suitable and applicable method, and to direct future studies for better quantification methods. This review is applicable only for building construction projects and did not include civil/infrastructure, demolition, renovation, and excavation projects. Six quantification methods and/or waste audit tool available from literatures are discussed, which include their limitation and future direction for this study. It is believed that some combination of these quantification methods could make a good impact in accurate numerical estimation of construction waste amount generated in building construction projects. A strong and accurate database as presented by Soliz-Guzman, combined with effective, vital, and resourceful estimation suggested by Jalali’s Global Index (GI), also with the aid of user-friendly software tool like the SMARTAudit could provide an effective and reliable waste quantification.

Antimicrobial activities of extracts derived from in vivo and in vitro grown Trifolium pratense ( Red clover)

Antimicrobial efficiency of extracts derived from Trifolium pratense (in vivo and in vitro grown plants, including callus) were examined using ethanol and methanol as solvents and tested against four bacterial pathogens (two gram negative and two gram positive) and three fungal pathogens. The antimicrobial activity of the methanol extract was found to give higher inhibition zone when compared with ethanol extract. Among the callus, in vitro and in vivo grown plants, the callus extract showed better antimicrobial activity, thus revealing a new potential use of callus of Trifolium pretense.

Phyto-evaluation of Cd-Pb Using Tropical Plants in Soil-Leachate Conditions

Sources of soil contamination can exist in various types of conditions including in the form of semifluids. In this study, 3 different types of tropical plants, Acacia (Acacia mangium Willd), Mucuna (Mucuna bracteata DC. ex Kurz) and Vetiver (Vetiveria zizanioides L. Nash), were tested under different levels of soil-leachate conditions. The relative growth rate, metal tolerance, and phytoassessment of cadmium (Cd) and lead (Pb) accumulation in the roots and shoots were determined using flame atomic absorption spectrometry. Tolerance index, translocation factor, metal accumulation ratio, and percentage metal efficacy were applied to assess the metal translocation ability among all the 3 types of plants. Significantly higher (P < .05) accumulation of Cd and Pb was exhibited in the roots and shoots of all 3 plants growing under the soil-leachate conditions. However, negative growth performance and plant withering were observed in both Acacia and Mucuna with increased application of higher soil-leachate levels. Vetiver accumulated remarkably higher total concentration of Cd (116.16-141.51 mg/kg) and Pb (156.37-365.27 mg/kg) compared with both Acacia and Mucuna. The overall accumulation trend of Cd and Pb in the 3 plants growing under the soil-leachate conditions was in the order of Vetiver > Acacia > Mucuna. The findings of the study suggest that Vetiver has great potential as Cd and Pb phytoremediator in soil-leachate conditions.

Coupling Material Flow Analysis (MFA) and Geographic Information System (GIS) Methodologies for Screening Flow and Emission of Biomass Energy in the Agricultural System

In the agriculture sector, sustainability retention of biomass management is a complicated issue, especially without increasing potential damage towards the environment. This study aims to develop an integrated MAGI conceptual framework using Material Flow Analysis (MFA) and Geographic Information System (GIS) to measure and display spatial biomass energy flow in an agricultural system in Kuala Terengganu. The scope for this research consists of two dominant pools namely crop production and livestock production. By integrating the MFA inventory data, biomass energy model for the year 2016 has been developed based on early results obtained. The study found that the major portion of the energy is focused in crop production, which is 56% higher than livestock production. The findings also estimated 35% agricultural waste recovery potential It seems that the integration of MFA and GIS is an interesting, ideal, and powerful combination of decision making tool because it is able to provide information and firm decision on the development of bioenergy management system and can be used to implement strategies to reduce energy use and pollutants released into the environment.