Chemicals are usually applied during water potabilization in order to promote coagulation by destabilizing colloidal particles, reducing surface repulsion forces, and thus allowing formation of more easily sedimented flocs. Sludge generated at water treatment plant (WTP) is a high moisture content residue that consists of impurities present in raw water, coagulants and other chemicals used in the process. Dewatering this residue in geotextile tubes can significantly reduce its volume, facilitating its handling and final disposal. This paper reviews the current state of the practice in designing geotextile closed systems for dewatering of WTP sludge, and the mechanisms related to its operation, addressing relevant aspects to be considered in the system design, such as the influencing factors on the filtration and dewatering efficiencies. Experimental methods, such as the dewatering cone test and the geotextile dewatering bag (GDB), usually conducted to select the most appropriate geotextile and chemical conditioning are also discussed. Thus, this work sought to expand the understanding of the WTP residue dewatering process on geotextile closed systems and to highlight the main issues involving its conception and achievement of the desired performance, in order to increase the acceptance and utilization of this technology.
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