Techno-Economic and Sensitivity Analysis of Rainwater Harvesting System as Alternative Water Source

Pg Emeroylariffion Abas,Tmi Mahlia

doi:10.3390/su11082365

Pg Emeroylariffion Abas, Tmi Mahlia

Open Access

https://doi.org/10.3390/su11082365

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Abstract

This paper formulates a rainwater harvesting model, with system and economic measures to determine the feasibility of a rainwater harvesting system, which uses water from the mains to complement the system. Although local meteorological and market data were used to demonstrate the model, it can also be easily adapted for analysis of other localities. Analysis has shown that an optimum tank size exists, which minimizes the cost per unit volume of water. Economic performance measures have indicated that rainwater harvesting system is currently infeasible to be implemented in Brunei; with capital cost and water price being shown to be among the prohibiting factors. To improve feasibility, a combination of rebate scheme on capital cost and raising the current water price has been proposed. It has also been shown that the system is more viable for households with high water demand.

Highlights

Rapid growth of the world population puts ever increasing demands on basic utilities, such as energy and water
Local Brunei data were used to determine system and economic feasibilities of the Rainwater Harvesting (RWH) system, with data from Table 1 being used as input to the RWH model
A mathematical model that may be used to simulate effectiveness of rainwater harvesting system, based on historical local rainfall data, with timescale that may be adapted according to rainfall data availability, has been proposed in this paper

Summary

Introduction

Rapid growth of the world population puts ever increasing demands on basic utilities, such as energy and water. Among areas that are related to water conservation, Rainwater Harvesting (RWH) may have the potential to be developed in Brunei, due to its abundance of rain all year round with average monthly rainfall of 248 mm, between 1984 and 2013 [12] This far exceeds the 45 mm minimum average monthly rainfall that was reported in Australia [13], a country that has successfully implemented the RWH system. In the context of Brunei, urban RWH system for household application (i.e., toilet, laundry and garden usage) is relevant This is because coverage of mains water distribution system is already extensive, reaching most of the population who mostly live in urban areas and use the most water. To make it more palatable for the people to implement the RWH system, water from the mains water distribution system shall complement water from the RWH system, to ensure that there will be no period whereby demand from the household cannot be met

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