**2. Hazardous sludge: properties and its potency**

The list of hazardous waste from non-specific sources found in Annex 1 of the Republic of Indonesia government regulation No. 101/2014 concerning the management of hazardous and toxic waste stated that sludge produced from integrated wastewater treatment facilities in industrial estate was classified as hazardous waste category 2 [10]. In this category, the waste in question is declared as toxic waste which is harmful to the environment and living things.
