Zainura Zainon Noor

Use of sewage sludge ash (SSA) in the production of cement and concrete – a review

The use of recycled sewage sludge ash (SSA) in Portland cement and concrete has attracted a lot of global interest due the increase in sludge production and the limitation of land availability where it is used as a soil conditioner. These are in addition to rising environmental concerns. The major components of SSA are SiO2, CaO, Al2O3, Fe2O3, MgO and P2O5. These compounds, in theory, make SSA a good pozzolanic material because when finely ground, SSA is found to be cementitious. Thus it can be used as cement replacement in Portland cement and concrete. Some of the advantages include reduction in waste disposal costs, provision of excellent sustainable practices, conservation of the environment provision of partial solution to land limitation problem for landfill. Some of its disadvantages are in terms of pozzolanic activity and strength coupled with high water demand which could be solved by adequate modification and treatment. This paper reviews the various use of SSA and summarises the progress made in the development of SSA as a partial replacement for Portland cement and concrete.

Temperature and air–water ratio influence on the air stripping of benzene, toluene and xylene

Volatile organic compounds in water and wastewater can be removed using air stripping. The effects of temperature and air-water ratios on the air stripping of benzene, toluene and xylene (BTX) from wastewater have been examined at a temperature range of 30–50°C and air-water ratios of 20–100. Removal efficiencies of >99%, >93% and 93% for BTX, respectively, were obtained at 50°C and air-water ratios of 100. The removal efficiencies increase non-linearly with temperature and air-water flow ratio. The effects of increasing temperature on the removal efficiency were found to be more significant at temperatures between 30 and 35°C than at 45 and 50°C. The effects of increasing water-air ratios on the removal efficiency were more significant at air-water ratios of 20–60 than at 80–100. The results indicate that a high removal of BTX can be achieved by operating the air stripper at high temperature conditions even at relatively low air-water ratios and vice versa.

A comparison of the efficacy of two strains of Bacillus subtilis and Pseudomonas fragii in the treatment of tannery wastewater

Abstract Tannery wastewater treatment using two isolated micro-organisms (Bacillus subtilis and Pseudomonas fragii) has been investigated in the present study. The growth patterns, pH normalisation and the abilities of these micro-organisms to reduce the concentrations of chemical oxygen demand (COD), total suspended solids (TSS) and chloride were studied using the shake flask apparatus. The specific growth rate and biomass concentration of B. subtilis and P. fragii were observed 0.138 h−1 and 3.01 mg/l and 0.051 h−1 and 2.34 mg/l, respectively, after 84 h. Both micro-organisms normalised pH of the wastewater. COD removal efficiency for B. subtilis was 87.6% while that of P. fragii was 85.2%. For TSS, B. subtilis caused a reduction of 91.7% (from 876 mg/l to 73 mg/l), while P. fragii reduced the solid concentration from 876 mg/l to 98 mg/l (88.8%). B. subtilis could only achieve 48.5% reduction in chloride concentration (from 127.08 mg/l to 65.39 mg/l compared to a reduction of 54.6% (from 127.08 mg/l to ...

Application of a packed column air stripper in the removal of volatile organic compounds from wastewater

Abstract Addressing environmental degradation and ensuring environmental sustainability are inextricably linked to all methods of reducing volatile organic compounds (VOCs) from the environment. A packed column air stripper is a typical example of such technologies for the removal of VOCs from polluted water. The present review is devoted to the applications of a packed column air stripper and, in comparison with previous reviews, presents further elaborations and new information on topics such as modeling and simulation of the dynamic behavior of the air stripping process in a packed column air stripper. The paper observed that a knowledge gap still exists in the synthesis of this knowledge to formulate practically applicable mathematical relationships to describe the process generally. Therefore, further researches are still required in the area of air stripper performance optimization, particularly in the development of a mathematical model and the optimization of an air stripper using a statistical experimental design method. Such a determination is critical to the understanding of the interactive effect of process variables such as temperature, air-to-water (A/W) ratio, and height of packing on air stripper performance.

Assessing Sustainable Municipal Solid Waste Management Factors for Johor-Bahru by Analytical Hierarchy Process

: Management of solid waste involves collection, transportation, treatment and safe disposal to landfills. These activities create a lot of impacts to the environment and most of the time impose social and financial burden on authorities handling solid waste management as well as the community. Local authorities managing waste are confronted with problems, protests and resistance from the public because of difference of views and perceptions on impacts created by waste management plans. This paper assesses some environmental, social and economical impacts viewed by stakeholders in the city of Johor Bahru Malaysia. Analytical hierarchy process (AHP), a multi-criteria decision making analysis tool is used to evaluate the views of the stakeholders with the aid of super decision software. Stream ecology, flora and fauna, habitat depletion, land use and air quality are ranked higher for environmental factors/impacts. Public awareness health and safety, population size and cooperation from the public dominate the social factors. Regulation, landfill capacity, operation and maintenance cost and capital cost dominate economic factors/impacts. Four alternative disposal plans (landfilling, recycling, incineration, composting) were proposed and ranked according to the priorities of the stakeholders. Incineration and recycling were preferred to landfilling and composting disposal options.

Benthic Macroinvertebrate Composition and Water Quality Status in Sungai Johor, Johor, Malaysia

Anthropogenic influences on aquatic life community can be identified using biological monitoring approach to assess pollution levels and water quality. This study was conducted for three times from November 2015 to February 2016 to determine the effect of land use on benthic macroinvertebrate assemblages in estuary of Sungai Johor. Five stations were selected and a 500 m reach of the stream was selected for each sampling site. Surber Net measuring 500 micron mesh size combined with a rectangular quadrat of 30 cm x 30 cm (0.09 m2) was used to sample macroinvertebrates. The results showed that un-disturbed river has complete sensitive taxa namely Ephemeroptera, Plecoptera and Trichoptera (EPT). There were only two sensitive taxa namely Ephemeroptera and Trichoptera were found in the river which flows through palm oil plantation. Similar scenario was found in the river which flows through logging area where there were also two sensitive taxa namely Ephemeroptera and Trichoptera found in this river. The results obtained for urban river was the other way around where there was an absent of all three sensitive taxa (EPT) in the river which flows through urban area. Most of the macroinvertebrate taxa that were found in this station are pollution resistant taxa comprised Diptera, Odonata, Mesogastropoda, Basommatophora, Hirudinea and Haplotaxida. The results can be used as a biological indicator for river water quality assessment.

Development of Sis on Solid Waste Management Through Selection: a Review

Along with the development of the nation, waste generation has been one of the critical issues that need immediate attention in a country. Effective and sustainable waste management system needs to be in place to carefully manage the waste generated, especially in the urban areas. Therefore, there is a need for the development of Sustainable Indicators (SIs), to continuously measure and monitor the sustainable performance of solid waste management system. This paper reviewed all the existing SIs that have been developed since the 1990s to monitor and measure the performance of solid waste management systems. The developed SIs are carried out through selection and aggregation processes. However, in this paper, only the development through selection is focused, where it usually adopts the Driving State-Force-State model. Although most developed SIs concentrated on the entire waste management system of an entire city, there are some SIs focused either on specific waste streams, or on specific waste management stages. Nevertheless, the developed SIs covered all the sustainability aspects of the waste management system, which are: economy, social and environment.

Integrated air stripping and non-thermal plasma system for the treatment of volatile organic compounds from wastewater: statistical optimization

This study examined the treatment of toluene and m-xylene from wastewater using integrated air stripping and non-thermal plasma (NTP) reactor system. Toluene and m-xylene concentrations, before and...

Predicting methane emissions from livestock in Malaysia using the ARIMA model

Purpose – The purpose of this paper is to compute the amount of methane generated from the waste of livestock from 1980 to 2008; then use the information in forecasting subsequent methane emissions by the sector in Malaysia from 2009 to 2020. Design/methodology/approach – The research study employed two approaches; computing methane emissions from 1980 to 2008 using the IPCC guidelines, and forecasting methane emissions for the animals from 2009 to 2020 using the autoregressive integrated moving average (ARIMA) model from the predictive analysis software (PASW-SPSS 18.0). Findings – Methane emissions from cattle, buffaloes and pigs accounted for over 95 per cent of total emissions and emissions from cattle are predicted to increase from 67.0 Gg in 2009 to 77.0 Gg by 2020. Emissions from the others will not be appreciable although poultry emissions will rise to 11.0 Gg by 2020. Attempt by the Malaysian Government to increase cattle production is not necessary at the moment as protein requirement has been m...

Energy Production from Natural Gas: Evaluation of Pontential Environmental Impacts Using Life Cycle Assesment Approach

Nowadays, sustainability is one of the main driving forces for worldwide economic growth especially in energy production. Conbustion of fuel such as natural gas for energy production not only produce electricity but also impacts to environment. In order to assess the environmental impacts of the natural gas power plant, study of life cycle assessment (LCA) has been carried out based on the data obtained from natural gas (NG) power plant in Johor, Malaysia. Data validation has been done by comparing the result with other assessment using the data available in the database. This paper presents the results of the LCA. From this study, it was found that there are insignificant differences in terms of the potential environmental impacts between the LCA study conducted using the data from the NG power with the assessment conducted using data from the database. Keywords Life cycle assessment, sustainability, energy, natural gas