Rafiu O. Yusuf

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.

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 0.138u2009h−1 and 3.01u2009mg/l and 0.051u2009h−1 and 2.34u2009mg/l, respectively, after 84u2009h. 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 876u2009mg/l to 73u2009mg/l), while P. fragii reduced the solid concentration from 876u2009mg/l to 98u2009mg/l (88.8%). B. subtilis could only achieve 48.5% reduction in chloride concentration (from 127.08u2009mg/l to 65.39u2009mg/l compared to a reduction of 54.6% (from 127.08u2009mg/l to ...

Air quality impact of diesel back-up generators (BUGs) in Nigeria’s mobile telecommunication base transceiver stations (BTS)

Purpose n n n n nThe introduction of mobile telecommunication services in Nigeria led to the development of base transceiver stations (BTS) across the country. Inadequate power supply from the national grid has led to massive use of diesel-fueled back-up generators (BUGs). The purpose of this paper is to attempt to quantify and inform relevant stakeholders about air quality implications of BTS BUGs. n n n n nDesign/methodology/approach n n n n nSeven major telecommunication network operators were identified. Emission factor approach was used to estimate the quantity of important air pollutants such as NOx, CO, SO2, PM10, PM2.5, PAH and TVOC that are emitted from the use of the BUGs based on fuel consumption rate and generators’ capacity. Fuel-based emission inventory and emission factor from the United States Environmental Protection Agency AP-42 and National Pollution Inventory were used to estimate pollutants emission from diesel-powered generators used in the BTS sites and amount of diesel consumed. Land distribution and per capita dose of the estimated pollutants load were calculated. n n n n nFindings n n n n nThe study showed that the deployment of BUGs will lead to increase emissions of these air pollutants. The states that are most affected are Lagos, Kano and Oyo, Katsina and Akwa Ibom states with respective total air pollutants contribution of 9,539.61, 9,445.34, 8,276.46, 7,805.14 and 7,220.70 tonnes/yr. n n n n nOriginality/value n n n n nThis study has estimated pollutant emissions from the use of diesel-fueled BUGs in mobile telecommunications BTS sites in Nigeria. The data obtained could assist in policy making.

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 67.0u2009Gg in 2009 to 77.0u2009Gg by 2020. Emissions from the others will not be appreciable although poultry emissions will rise to 11.0u2009Gg by 2020. Attempt by the Malaysian Government to increase cattle production is not necessary at the moment as protein requirement has been m...