Early warning systems (EWS) in drinking water supplies: Performance evaluation and feasibility of application in developing countries

Abstract

Drinking water quality has become a central issue to the global water crisis in developing countries. Much of the problem is a reflection of poor water management and priority dedicated to improving a basic need. The implementation of an automatic system would detect changes in water quality parameters in real-time and warn decision makers of a potential contamination event , so they can respond effectively. Such systems known as early warning systems (EWS) have been applied to drinking water systems in developed countries, to maintain and ensure acceptable water quality for the benefit of safeguarding public health. Considering application of such a system on the basis of need, an opportunity arises for potential application of EWS in developing countries. On account of typical situations demonstrating instrument failure when applied in a developing country, the feasibility of a EWS in a developing context can be realized from performance evaluations (i.e. in a developed country). This study explored the application of EWS in a local water utility; that is the LiquID analyser, manufactured by ZAPS Technologies, Inc., and tested at the Onehunga Water Treatment Plant , in the Auckland region. Therefore a trial methodology was developed to evaluate instrument performance by spiking solutions of known concentrations into the sample feed of the LiquID analyser , which aimed to assess the accuracy of the instrument to detect the nature and concentration of the spiked solutions. A preliminary assessment of the EWS via calibration revealed that the LiquID analyser measured significantly higher values for turbidity at 1.5 ± 0.13 NTU and UV absorbance at 1.73 ± 0.03 m-1 against the turbidity analyser and S::CAN Spectro::lyser which measured turbidity at 0.22 ± 0.15 NTU and UV absorbance at 1.31 ± 0.01 m-1, respectively. In addition total organic carbon readings for the LiquID analyser at 1.284 ± 0.001 mg/L were more than double of the lab measurements of 0.5mg/L. The results revealed the LiquID analyser consistently measured higher values than other instruments. Furthermore, the small variation in standard deviations suggested that although the instrument produced inaccurate measurements, its readings were reasonably precise. Through continual calibration instrument accuracy can be realized. An important finding from the preliminary assessment of the EWS via calibration was that the common perception that systems operate in an automatic fashion was not realized as it was demonstrated much more time and effort was required than suggested by manufacturers, as delays due to installation, calibration and operation proved more serious than anticipated. Consequently, evaluation of the instrument performance by spiking solutions was not realized. This incident suggested that the delays and challenges of system performance experienced in developed countries are likely to be much more of a challenge in developing countries. Due to the various limitations in resources, infrastructure, local knowledge and accessibility, approval of sound performance in developed countries is necessary before feasibility of application in developing countries can be adequately assessed. Nonetheless, the benefits of applying EWS in developing countries can be realized without a performance assessment, whereby improvements are expected in the areas of health, water security, policy enforcement, maintenance monitoring and capacity building. The holistic perspective of transferring technology to developing countries is the potential to improve the state of development. Technologies implemented successfully have the potential to improve economic development and existing infrastructure. But the appropriateness of the technology and the successful transfer process can go unrealized if local ownership is not established. This reality is most apparent when considering the financial matter of the scenario whereby affordability is determined by perceived priority. Observation of the national budget often reveals more investment towards agriculture and defense compared to drinking water supplies. Unless communities within developing countries take ownership of their basic needs, with financial investment to back it up, then technological solutions can be realized, transfer processes will be successful and drinking water quality can be improved, and perhaps the global crisis would become yesterday's news.