Impacts of process selection and process train in the design of water treatment plants in South Africa

Abstract

Background The South African Government is spending huge amounts of money (about R64 billion for the fiscal years 2015/16 to 2018/19 as per the revised strategic plan – vote 36) and more than R30 billion was targeted water infrastructure investments by the end of 2014/15 financial year (Ruiters & Matji, 2015) striving to provide all its citizens with access to good quality water services through its organs of state such as municipalities and water boards. A study of more than one hundred (100) waterworks carried out throughout the country in the early years of the 21st century by Chilton and Polasek (2013) revealed that none of them was found to be appropriately designed in terms of the processes installed.

The author of this dissertation aims to bridge the gap in Chilton and Polasek’s (2013) study of more than a hundred (100) waterworks, in which they did not quantify the actual impacts caused by the design flaws they identified. The present study was carried out on four waterworks situated in two provinces, namely Gauteng and North West. The aim was to quantify the financial implications, operations and maintenance complications/difficulties.

The four methods used to carry out this study are: Initial design catering for the ultimate plant capacity; design conforming to surface water treatment regime; actual operational performances of plants; and financial implications for the clients of the case study plants selected.

The approach was to compare the design against the recommended and well documented treatment regime applicable to surface water, selection of processes, design and installation using the four methods mentioned above. All the water treatment plants selected as case studies for this report have several inherent design deficiencies which negatively affect the ability to produce good quality potable water, and to promote and facilitate water services delivery most cost effectively in a sustainable manner. Inherent design deficiencies confirmed in the four case study plants include failure to cater for the ultimate design capacities; failure to utilise the value engineering tools in the design; poor selection of processes and their arrangement and negative financial Implications for the owners of these waterworks.

The report recommends formation of a Water Treatment Design Committee (WDC) or a National Water Agency of South Africa (NWASA) responsible for water capital projects implementation.

Keywords: conventional, water treatment, process, South African Government, waterworks, guidelines, capital project, consultant, engineer, and services delivery.