A B S T R A C TThe use of wood as a filter element for water treatment can be an efficient, low-cost alternative because wood is a renewable material. Therefore, pioneering a study to examine the possibility of filtering water through wood was advantageous. In 2002, the first experiments with wood filtration in the perpendicular direction of fibers were conducted (Correa and Sens [1]). With the continuation of this study, a new research developed as presented in this article. This study was conducted in two steps by the construction of pilot systems. The first step studied deadend filtration and the second step studied helical cross-flow. The three species of wood studied were: caixeta (Tabebuia cassinoides Lam P. DC.), garapuvu (Schizolobium parahyba Vell. Blake), and pine (Pinus elliottii). The images obtained in the scanning electron microscope had the same approximations for all the three samples in the pores' direction as well as in the direction of fibers. The porosity of the wood fits within the size of the microfiltration. The observation of the wood's permeability revealed that the more porous the wood, the greater the permeability and the smaller the apparent mass. Filtration in the perpendicular direction of the fibers did not prove valuable because of its very low filtration rate and the need for high working pressure. Pine proved to be the superior option when considering the quality and production of water in the dead-end filtration. In this study, the value for wood density which is calculated to be 0.50 g/cm 3 and the porosity in the range of 40% proved to be significant factors for this treatment system. This implied a correlation between wood density and its porosity when choosing wood for water filtration. With respect to the observed wood, the pore diameter with higher performance was approximately 0.02 mm. The results in the helical cross-flow filtration generated an average removal of 70% to apparent color removal and 93% for average turbidity. The working pressure did not exceed 40 psi for a filtration rate of 15 m 3 /m².d. The helical cross-flow filtration tests involving coagulation showed enhanced results and higher efficiency. Fouling on the surface of the wood reached a depth of 5 mm, not found in 10 mm. In summary, this treatment system exhibited improved and cost-effective results with minimal power consumption due to low working pressures.
This work is the first part of a national review about Bank Filtration (BF) that began in 2003, in Brazil. These studies were conducted in the laboratory and in the field with water and natural sediment from the study regions, showing how BF has been efficient worldwide for the treatment of water for public supply as an alternative treatment. It aims to show the synthesis of results to date and point out its main benefits and challenges; that is, the state of the art at the national level. The review is concentrated in Santa Catarina (part 1), Pernambuco and Minas Gerais (part 2). BF demonstrates efficiency in reducing parameters such as turbidity and coliforms (total and fecal), pesticides and toxins. However, BF showed low capacity in reducing parameters such as salinity and true color. BF is highly dependent on local geological conditions, so parameters such as iron, manganese, fluorine, alkalinity, hardness, and chlorides can be added to the treated water. Keywords: Water Treatment. Bank Filtration. Public Supply Systems. Natural Sediment. Water Quality.
This work is the second part of “A Review of seventeen years of bank filtration in Brazil: results, benefits, and challenges”. Part 2 describes the research on water treatment carried out in the states of Pernambuco (Olinda city, metropolitan region of Recife and region of Garanhuns) and Minas Gerais (Viçosa city). The main benefit of bank filtration (BF) is that it is an alternative way of obtaining a higher quality raw water compared to the traditional water supply methods when local geological conditions are favorable. BF technology highlights other relevant aspects: it may become one of the main water pretreatments in rivers or lakes with sandy sediments; it is possible to obtain quality water in a well up to the first impenetrable layer (30 m deep); the technology removes 100% of total and fecal coliforms; it may reduce water turbidity at high levels; its pretreatment application may reduce the amount of inputs in the water and, consequently, the generated sludge. Keywords: Bank Filtration. Water Treatment. Local Geological Conditions. Pretreatment. Impenetrable Layer.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.