Water Treatment by Fabric Capillary Action: First Mathematical Model

摘要

Last year, a new water treatment method has been introduced which wasaccomplished by transmitting the water from a channel to another through technicalfabrics by the capillary action, leaving the suspended solids as well as other pollutantsat the inlet channel while the rest of the pollutants retained across the fabrics. It wasfound that the new method is capable of removing turbidity, algae, and bacteria withremoval efficiencies up to 95, 90, and 80% respectively. On the basis of the factorialexperimental work, this study presents the first mathematical model to calculate thedischarge according to the influent turbidity, hydraulic conditions and fabriccharacteristics. As a preliminary objective, a laboratory study was conducted to obtainthe best hydraulic conditions for the water transmission across the fabric as well as todetermine the impact of different fabric characteristics. The tested hydraulicconditions includes the water level before (upstream) and after (downstream) thefabric, and the free sagged length of fabric in the downstream. Moreover, the impactof the influent turbidity on the overall performance was tested through another set oflaboratory experiments at the best hydraulic conditions. Data collected from thelaboratory tests were analyzed using SPSS program. The simulated results showedthat the transmitted flow increases significantly with the increasing of the upstreamwater level as well as the increasing of the free sagged length of fabrics. Thedeveloped mathematical model was applied on a pilot scale plant which was designedto treat 8 m~3.d~(-1) as an average flow using natural surface water. The pilot plantconsisted of a rectangular tank similar to the up-flow sedimentation tank with somemodifications. Outlet weirs were arranged in a uniform shape at the top of the tankand the nonwoven technical fabrics were placed among the crests of the weirs. Theplant has been tested under different influent characteristics as well as influentturbidity (from 7.50 to 20 NTU). Results obtained from several runs showed that theR square value was found to be around 0.98 and the most suitable type of theexperimented fabrics was the nonwoven multilayer polyester fabrics (100 %Polyester).