| Popis: |
This paper systematically documents the impact of the 2010-2011 Canterbury earthquakes on the city of Christchurch’s wastewater collection, treatment and disposal system. Major problems arose at the city’s wastewater treatment plant because liquefaction generated large quantities of silt and sand (535,000 tonnes) some of which entered the sewer system and overloaded the plant’s main solids-handling facilities (i.e. the primary sedimentation tanks). The second quake to hit Christchurch (on the 22nd of February, 2011) was a magnitude 6.3 with a maximum recorded intensity of 2.2 g. One of its main impacts at the sewage treatment plant was a loss of power to critical facilities. Some processes failed simply because operators were unable to forecast what would happen when power was restored. The effect on each major wastewater operation is discussed in this paper noting that slumping of the oxidation pond banks was estimated to cost around $20 million NZ$ to repair (the lion’s share of the repair bill for the sewage treatment plant). The role of the 38,000 chemical toilets as well as portable toilets in assisting with the initial earthquake recovery is also highlighted in this paper. Christchurch serves as an excellent case study, offering valuable insights into how engineers assess wastewater infrastructure impacted by earthquakes. In particular, lessons can be learned about toilet deployment strategies and the ability of a medium-sized city to rapidly get a sewage treatment plant operational again. |
