Sludge dewatering with geotextile refill in a draining container: case study in a water treatment plant

Abstract

Population growth culminates in the generation of a significant amount of waste, including waste generated by water treatment processes, which results in a wet waste called effluent. This effluent must be treated and cannot be released directly into nature. One of its treatment steps is the separation of the solid and liquid phases, through dewatering techniques. This work presents a case study that uses a dewatering technique with geotextile tubes, on a mobile cradle composed of a roll on roll off container, an innovative technique that can significantly contribute to the sustainability and safety of the process. This case evaluates the operation of this technique in a complete cycle water treatment plant with an equalization tank, generating 20 m³ of sludge daily. Filtration and dewatering efficiencies are addressed, as well as increasing of the solids content by cake mass. Still, the ecosystem service of the water body in providing raw water is discussed and environmental valuation by indirect replacement cost method is briefly approached. Through the use of the dewatering technique in a special draining container, its effectiveness in separating the solid from the liquid phase can be seen, obtaining filtration efficiency greater than 90%, dewatering efficiency greater than 2000% and satisfactory solids contents for correct disposal at the authorized landfill. It is also noticed the environmental feasibility of using the dewatering technique, where the cost of its use represents less than 6% of the environmental value attributed to the water body in providing raw water for the station.