Rebecca Schneider and Meghan Furton
Abstract:
The Sand Source and Test Methods sub-team is new to AguaClara this semester. Our main sources of research come from the known SRSF sand constraints, which dictate that no sand should be able to slide through the 0.2 mm slots in the PVC pipe, the sand should be hard and not prone to dissolution in acid, the backwash velocity required to expand the filter bed by 30% should be very close to 11 mm/s, and the sand bed must not have significant stratification after backwash. In addition to the constraints provided by the SRSF, the filter sand used must also satisfy American Water Works Association guidelines (AWWA). We are using American Water Works Association (AWWA) media constrains along with the American Society for Testing and Materials guidelines (ASTM International) to compile a series of test methods for filter sand. We intend to determine which of these constraints apply to the SRSF design. Furthermore, progress towards local sand acquisition is varied between the sites in India and Honduras as of September 2013. In India, sand is currently taken from the Barakar river and the only modifications made are sieving it for correct size on site, using two large rectangular mesh sheets that are shaken by two people. The two sieve sizes currently in use are No. 60 and 30, which correspond to particle sizes of 0.25 mm and 0.5mm respectively. There is also potential access to laboratories in the Universities and NGOs nearby. In Honduras, on the other hand, there is not an established sand mine industry and sand will likely be taken from river beds near the site. Transporting this sand from the river to the site is easy, but testing will be done in the apartments without the use of laboratory equipment that is difficult to transport.
