Recycling concrete is a significant step towards eco-friendly construction practices.

Abstract:In the period 1990-2012, the percentage for open defecation has dropped by 11% in sub-Saharan Africa which has resulted to substantial progress in access to improved sanitation facilities i.e. pit latrines, VIPs, septages and centralized sewage facilities since 1990 [ figure 1]. This therefore put at ease the operations of many municipal's water resource and waste management agencies. Recent investigation confirms that the number of people defecating in the open is currently increasing in 26 of 44 countries of sub-Saharan Africa and this unsustainable practice is predicted to persist as long as there are toilets that are dysfunctional or unhygienic (WRC, 2015) in Africa. Per review conducted, the unhygienic and dysfunctional conditions of public toilets facilities are results of poor sludge management operations of which inconsistent collection of faecal sludge from toilet sites is a major part. Reported cause of inconsistent emptying of faecal sludge at sanitation sites is due to higher cost of faecal sludge management(FSM) services within urban and peri-urban settlements. FSM services comprise of three stages i.e. collection, treatment & re-use, and disposal of which the treatment stage accrue the most cost of the services. Treatment cost depends on treatment techniques applied by sanitation inspectors/operators but there is currently no definite treatment method which is the most suitable as the physico-chemical properties and environmental compliance requirements for disposal of faecal sludge is highly variable and most solutions have not been demonstrated at scale. To be precise on the key scope of study, on-site sanitation & centralized facility faecal sludge treatment techniques and management practices are deemed the core basis of study hereafter. In this paper, anaerobic-aerobic phosphorous removal process (A/O) is selected as an efficient and cost-effective centralized facility sludge treatment technique and its applied to a case study in Bujumbura municipal of Burundi. Also a simple but effective on-site sanitation management plan which is feasible in Africa communities is discussed.

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Vertical irregularity tends to have an adverse impact on the seismic effect on structures, but currently, there is the lack of appropriate research on the use of isolation technique to reduce seismic effect and issues related to a weak story. This paper focuses on the analysis of isolated vertical irregular structure in both scenarios of mass distribution and stiffness distribution. Discussion on the influence of shear forces distribution pattern, damping coefficients and other parameters caused by the irregular distribution of story mass and stiffness is made. According to previous works cited and our case study analysis, it concluded that base isolation of irregular structures ensures better seismic resistance by reducing base shear and improving damping characteristics.

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