Development of polyester needle-punched nonwoven fabrics for filter press applications

This paper reports the development of nonwoven fabric by needle-punching technique for filter press application in textile effluent treatment plant. For filter press development, the nonwoven fabric was reinforced with the nylon scrim as the central layer in order to withstand the filtration pressure. The nonwoven fabrics were developed using different denier polyester fibres and changing punch density. The influence of fibre fineness and punch density on the properties of nonwovens was investigated. The filtration parameters such as filtration efficiency, dewatering efficiency, blinding tendency and cake discharge properties of the developed nonwoven filter fabrics filter fabrics were evaluated and compared with existing woven fabric filter media. The influence of calendering on the filtration properties of the nonwovens was also studied. The results showed that bursting strength of the developed nonwovens increased with increase in fibre fineness and decrease in punch density. It was also found that the air permeability of the developed nonwovens varied inversely in relation to punch density and the proportion of fine fibres. It was observed that developed nonwovens had 8% higher filtration efficiency and 6% higher dewatering efficiency compared to the existing woven fabric filter media. The blinding resistance and cake discharge properties were slightly lower than that of woven fabric filter. It was found that calendering improves filtration properties of the developed nonwoven fabrics.