"In the 1880s further fears over possible health concerns because of the outfalls led to the MBW purifying sewage at Crossness and Beckton, rather than dumping the untreated waste into the river,[90] and a series of six sludge boats were ordered to ship effluent into the North Sea for dumping. The first boat commissioned in 1887 was named the SS Bazalgette; the procedure remained in service until December 1998, when the dumping stopped and an incinerator was used to dispose of the waste."