| Booster Chlorination is the addition of chlorine at some critical locations of a water distribution network (WDN) such that chlorine residuals are maintained at a level greater than the minimum for public health. Building on the worldwide previous work, here an optimization model with two stages is formulated for the dynamic schedule of booster chlorination based on water quality safety. The first stage is solved by greedy algorithm targeting at locating the minimum number of booster stations (minimum construction cost) which supply enough chlorine residuals within a WDN. The second stage determines the optimal chlorine injection rates by using the desired chlorine residual level to allow a lower average chlorine and decrease the variability of chlorine residuals throughout a WDN, which lead to a lower total dosage and may reduce the formation of DPBs. Given the differences of size and water demand between WDNs, the second stage formulates two different optimal models, which are both solved by Lingo8.0. This dissertation applies the optimization model to two WDNs, a test-bed example to illustrate the characteristics of this model and a real WDN to improve its water quality. The conclusion is that booster chlorination allows a better water quality as well as a lower chlorine dosage.Also, reliability analysis of WDNs can supply scientific advice for their facility installment, up-gradation and maintenance. However, there are few research having been done in the field of water quality reliability analysis. Therefore, a method of water quality reliability analysis under booster chlorination considering water demand variations is formulated in this dissertation, which also includes a development of this method under linear superposition. The two WDNs mentioned above are evaluated by this method. The results suggest that booster chlorination can maintain a high reliability without impairing its advantages in improving the water quality and reducing the economic cost.
|
PDF Full Text Request