Mobile water filtration enables on-site recycling of wastewater for reuse in mechanical decoking operations of fired-heaters, furnaces, boilers, or systems prone to build up of deposits, residue, or scale and enables on-site disposal of wastewater in a safe and environmentally conscious manner. In batch operations, a coagulant, a flocculant, and a plurality of cascaded filters of increasingly fine pitch may be used to treat wastewater and remove particulate matter, such as, for example, coke, for reuse or safe disposal. In continuous operations, a plurality of cascaded filters of increasingly fine pitch may be used. A control system may be used to automate the operation of a mobile water filtration system for use with a decoking system, such that it does not require human intervention exception for maintenance operations related to filters. The filtered water may be disposed of on-site, eliminating the need for further treatment or transport off site.