Aloe sp. leaf gel and water glass for municipal wastewater sludge treatment and odour removal

Aloe gel (Alg), which is a natural extract from the Aloe sp. plant, was evaluated in this study for its potential use as a bioflocculant to treat urban wastewater sewage sludge. The gel was used alone and combined with water glass (WG) under controlled conditions in laboratory experiments. Alg was found effective to settle the flocculated sludge rapidly and remove distinctive unpleasant odours of the sludge as highlighted by gas chromatography-mass spectrometry (GC/MS) analysis. Furthermore, Alg was pH tolerant and had no effect in changing the pH of the wastewater. The optimum dose of Alg was 3% at which a sludge volume index (SVI) of 45.4 mL/g was obtained within 30 min settling time. To enhance the treatment performances of Alg, WG was also evaluated as an alkali agent to further reduce the chemical oxygen demand (COD) and ammonia (NH4-N) in the wastewater. At equal doses of 3% of WG and Alg each, the combined treatment outcomes showed high turbidity and NH4-N removals of 83 and 89%, respectively, but the overall COD removal was at best 25%. The settling rate of treated sludge with combined Alg/WG was very rapid giving an SVI of 25.4 mL/g within only 5 min.

Assessment of Passive Architectural Strategies for Natural Ventilation in Libraries within Hot- Humid Climate

In buildings, natural ventilation is for human comfort; for odour removal, body and the structure cooling. A previous study revealed that libraries in Nigeria could not function efficiently without artificial ventilation and lighting. Artificial ventilation, aside from economic disadvantages, it is not reliable and anti-sustainability while natural ventilation is reliable, consume less energy, and in other words, it is more efficient when compared with other types of ventilation. The research evaluates the application of passive architectural strategies for natural ventilation in libraries within the hot-humid climate of Nigeria, intending to recommend natural ventilation strategies in libraries. Ten (10) libraries were selected randomly in the study area from both institutional and public libraries. The research conducted using observation schedule, the variables in the research are; Window types, Clerestory windows availability, Door openings, Screen walls, Courtyard, Other openings, use of external shading devices and orientation of the library. The data analysed using descriptive statistic; the results presented using tables, bar charts and pie charts. The research revealed that 29% of the cases studied use external vertical structural shading devices, 36% use horizontal shading devices, 21% use both vertical and horizontal shading devices to deflect solar radiation and 14% do not use any external shading devices. 80% of the libraries studied was oriented toward north-south (NS) direction, while 20% oriented toward east-west (EW) direction. Therefore, the majority of the libraries studied have desired orientation; however, each lacks one of the passive cooling strategies. Adequate natural ventilation in the libraries is achievable by the proper synthesis of the building orientation, proper design of building internal spaces, the proper position of window openings and use of projected window as well as clearstory. More so, further study to enhance natural ventilation configuration for the study area is desirable.