1200016 Kolkata's brick sewer renewal: history, challenges and benefits

摘要

In 1980-1981 Calcutta authorities with the support of the World Bank surveyed the extent of solids in the city's sewers and instigated pilot works to study how to clean and renovate the system. I can confirm that the huge volumes of solid matter were as bad then as has been reported by Basu et al. (2013). However, at that time domestic water supply to parts of the city was only operable for two brief periods each day and the main pumps were old and unreliable and consequently used on the same setting all day. This resulted in the system always operating under surcharge with no hope of achieving a reasonable hydraulic gradient to move any solid matter. A pilot study at Manicktala showed that once a sewer had been cleaned, and if pumps were used to match the flow, hydraulic flush could be achieved.