Ahmad Halilu Abba

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.

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.

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...