The treatment of fecal sludge is being achieved by co-treatment with sewage in STPs or treatment at FSTPs. Traditional centralised systems require large capital expenditure and have many constraints, to be established in the ULBs with smaller populations. These constraints are in the financial, technical and operational aspects. At the same time, most of the STPs in Tamil Nadu are utilised to only around 60% of their capacity. Thus, clustering of neighboring ULBs for co-treatment allows existing facilities to be used to their optimum capacity while at the same time enabling ULBs without treatment facilities to gain access to treatment in a cost-effective way.