To begin with, it is crucial that you specify the type of sludge produced: for example, is it essentially organic or biological; does it contain heavy metals? etc.The answers to these questions will determine the type of sector in which the sludge might be useable. For instance, you may be able to adapt it to certain agricultural practices.
I agree with @Amphinitrate Sludge from the textile industry, in particular, cannot be used for composting.But since the term "textile" is quite broad, it is essential to determine the origin and content of the sludge.
Fully concur on the need to properly identify the type of sludge and its components before going any further in the choice of sludge management system. This can start with a precise identification of the processes used to generate the sludge and what chemical or other additives were used. This will help guide you towards any analyses that need to be carried out later. You might want to consult your local wastewater authority to see if they have any documentation on the subject.