Selection of an appropriate risk assessment tool for waste water risk abatement planning: an eThekwini case study

Abstract

A Wastewater Risk Abatement Plan (WWRAP) has become an integral part in the operation of wastewater treatment plants across South Africa with the introduction of the Green Drop initiative. With each successive Green Drop season the WWRAP has become more of a focal point of the assessments and is intended to engender a more risk aware and risk averse philosophy into the operation of wastewater plants. The WWRAP, itself, is intended to be used as a tool to prioritize the deployment of limited resources and funds to achieve better compliance and management of wastewater treatment plants across the country. This is only effective if the method used for rating risk successfully identifies risks inherent on the plants. In essence the WWRAP will not achieve its objectives unless risks are properly identified. This paper explores the two successive WWRAPs produced by the eThekwini Municipality and the evolution of the risk rating systems employed. In 2011 the eThekwini Municipality's WWRAP was based on a modified risk matrix as proposed in the Draft Guidelines for the development of WWRAPs by DWA and the WRC. While the results of this assessment generally correlated with the Department of Water Affairs' Cumulative Risk Rating assessments, the rating system was based primarily on health targets and as a result was ineffectual as a tool for prioritization of resources. In 2012 with the next revision of the WWRAP there was a need to further ‘tweak’ the risk matrix used in order to more accurately reflect and identify risks on the various plants. This entailed increasing the complexity of the risk rating methodology and care was taken to ensure usability while still enhancing the efficacy of the risk assessment process. It was decided that ‘Administrative’ or ‘Reputational’ risk be taken into account when evaluating risk at the various plants and the risk assessment matrix was adjusted accordingly. It was decided that both administrative and reputational risk could be adequately represented by the influence that a particular risk had on the Affairs' potential Green Drop score. Multiple permutations and approaches were evaluated to determine which method would best reflect the ‘on the ground situation’. Using the new rating system, a total of 1,235 low risks were identified over the previous year's 913, medium risks numbered 223 over the 17 from 2011 and 105 high risks were identified for 2012 as compared to 2011 where no high risks were identified at all. The new rating system was thus deemed a more appropriate tool for the prioritization of resources for the municipality.