"will render irresistible the conclusions at which he has arrived in regard to the influence of the water-supply in causation of the epidemic." It was the last outbreak of the disease in the capital. In 1878 a Thames pleasure-steamer, the , collided with the collier Bywell Castle and sank, causing over 650 deaths. The accident took place close to the outfalls and questions were raised in the British press over whether the sewage was responsible for some of the deaths. 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, 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. The sewers were expanded in the late 19th century and again in the early 20th century. The drainage network is, as at 2015, managed by Thames Water, and is used by up to eight million people a day. The company said in 2014 that "the system is struggling to cope with the demands of 21st-century London". Crossness Pumping Station remained in use until the mid-1950s when it was replaced. The engines were too large to remove and were left in situ, although they fell into a state of disrepair. The station itself became a grade I listed building with the Ministry of Public Building and Works in June 1970 (since replaced by English Heritage). The building and its engines are, , under restoration by the Crossness Engines Trust. The president of the trust is the British television producer Peter Bazalgette, the great-great-grandson of Joseph. As at 2015 part of the Abbey Mill facility continues to operate as a sewage pumping station. The building's large double chimneys were removed during the Second World War following fears that they could be used by the Luftwaffe as landmarks for navigation, and the building became a grade II* listed building with the Ministry of Works in November 1974. The provision of an integrated and fully functioning sewer system for the capital, together with the associated drop in cholera cases, led the historian John Doxat to state that Bazalgette "probably did more