Feasibility of an environmentally friendly method of contaminant flushing in water distribution systems using containment ponds

Water distribution system flushing is one way to get rid of contamination. In conventional flushing, all the contaminated water gets discharged to the environment, thereby harming it. A new method is proposed here as an alternative solution, in which a containment pond lined with impermeable material will be constructed in a suitable place within the municipality. Network modelling was performed to investigate the feasibility of the new method. It was found that (1) the proposed flushing method can successfully reduce environmental impacts compared to hydrant flushing only, (2) a containment pond cannot clear the system periphery away from the containment pond, (3) the best location of a containment pond is not always at the furthest location from the source reservoir, and (4) for some systems, some pond locations might be better from an economic perspective, while other locations will be better environmentally.

Flexible and deterministic household water saving under water demand uncertainty: existing water distribution system and sanitary sewer perspectives

An integrated method that evaluates conflicting hydraulic performances of water distribution systems (WDSs) and sanitary sewers (SSs) considering water-saving schemes (WSSs) under fixed (deterministic) or uncertain water demands was formulated. WSSs considered include household water-saving fixtures and appliances whose water flows impact water distribution system (WDS) and sanitary sewer (SS) hydraulic performances in different ways. In the proposed flexible approach, a multi-objective optimisation problem was formulated and solved considering trade-offs of three objectives: (1) maximisation of the average cost savings (2) maximisation of the average WDS resilience index and (3) minimisation of the average SS self-cleansing velocity deficit factor. The decision variables include water-saving fixture and appliance capacities that are applied in a deterministic or flexible manner at a household level. The constraints include WDS and SS hydraulic requirements together with decision bounds of the available water-saving scheme capacities. The non-dominated sorting genetic algorithm was used to obtain trade-off solutions. This method was demonstrated in the corresponding WDS and SS network subsystems of Tsholofelo extension in Gaborone, Botswana. The results indicate that WSSs lead to visibly conflicting WDS and SS hydraulic performances. Moreover, considering uncertainty inherent in water demand and the corresponding planning and management of WDSs and SSs provides more sustainable solutions as demand uncertainties unveil.

Hydraulic optimization of the physical parameters of a drinking water distribution system

Drinking-water distribution systems are generally designed with methodologies based on trial-and-error tests, which generate feasible results. However, these trials are not the most economical and reliable solution since they do not consider the optimization of the network. For the present work, the hydraulic model of the drinking water distribution network of San José de Cúcuta, Colombia, was optimized by applying the concept of resilience rate and minimum cost. The development of the work consisted of the hydraulic modeling of the physical components of the network in EPANET software, as well as the application of calculations of the connectivity coefficient and the unitary power of each section. With the data obtained from the modeling and calculations, the physical parameters were optimized, and the cost-benefit ratio was estimated. It was found that the current drinking water distribution system does not have a power surplus to overcome a system failure. The optimization increased the total energy surplus of the network (261%) and the resilience rate (585%). Also, the connectivity coefficient was improved with an average value of 0.95. The hydraulic optimization methodology applied resulted in a network resilient to system failures.

Analysis of water distribution system at Alang-Alang Lebar

Municipal Waterworks Tirta Musi manages and supplies clean water to Palembang city. The distribution network system of Municipal Waterworks Tirta Musi is expected to distribute water sufficiently to all customers in the 18 districts this Municipal Waterworks serves. However, it was found that in Alang-alang Lebar service unit water was not delivered sufficiently. Moreover, Alang-alang Lebar service unit plans to improve the service so that the system will serve increasing customers until the next 20 years. This study aims to analyze the water distribution system to find the cause of insufficient water in Alang-Alang Lebar; predicting the number of customers in the next 20 years, and propose some improvements in the distribution system. A computer program EPANET was used to conduct the simulations on pipe networks. Data required for hydraulic analysis using EPANET was obtained from Municipal Waterworks Tirta Musi. The result shows that head pressure was the main problem in Alang-Alang Lebar. Adding discharge of pump reservoir, enlarging pipe diameters in some parts will improve the distribution performance. The proposed design of the distribution system will be able to deliver water for the next 20 years with an increasing number of the customer.