This study presents energy-efficient solutions for wireless sensor systems intended for the monitoring of water quality at water stations. Energy problems, such as energy scarcity and energy consumption in wireless sensor networks, are critical issues that raise concerns when it comes to defining the lifetime of a network. This can be attributed to the finite energy budget of water quality sensor nodes and also the lack of energy-efficient schemes. To address these energy problems, a detailed study has been carried out in this paper on some of the major approaches developed to address energy issues in wireless sensor systems, and dedicated to the monitoring of water quality applications in a way that contextualizes the considered solution methods. Furthermore, the solution methods are classified, while their strengths and weaknesses are also identified. Also, several suggestions are made on solution methods towards further improvement. Therefore, this study suggests a reasonable direction for future studies on developing energy-efficient solutions in wireless sensor systems for monitoring water quality applications.

This paper considers newly emerging wireless technologies that can be explored for potential exploitation in the future wireless sensor network solutions for water quality monitoring applications. The reviewed technologies promise to address long-standing issues that confront existing wireless sensor network solutions devoted to the monitoring of water quality parameters. Such issues include energy efficiency and long-range water quality data communication. These issues can be attributed to the shortcomings of legacy communication networks commonly combined with wireless sensor network solutions, due to a discrepancy caused by traditionally powering the sensors nodes using batteries. In particular, some of the legacy communication networks suffer from short communication range, while others are limited by high power consumption. These shortcomings provide scope for the utilization of newly emerging solutions identified in this study to advance the field of a wireless sensor network for water quality monitoring. To achieve this, three key categories of communication networks have been recommended in this paper, including their architectural design and network deployment for water quality monitoring applications. Also, this paper provides future directions on the identified communication networks to enhance their performance for the next-generation of wireless sensor network solutions for water quality monitoring applications.

This work presents a new approach to the maximization of energy and throughput in a wireless sensor network (WSN), with the intention of applying the approach to water-quality monitoring. Water-quality monitoring using WSN technology has become an interesting research area. Energy scarcity is a critical issue that plagues the widespread deployment of WSN systems. Different power supplies, harvesting energy from sustainable sources, have been explored. However, when energy-efficient models are not put in place, energy harvesting based WSN systems may experience an unstable energy supply, resulting in an interruption in communication, and low system throughput. To alleviate these problems, this paper presents the joint maximization of the energy harvested by sensor nodes and their information-transmission rate using a sum-throughput technique. A wireless information and power transfer (WIPT) method is considered by harvesting energy from dedicated radio frequency sources. Due to the doubly near–far condition that confronts WIPT systems, a new WIPT system is proposed to improve the fairness of resource utilization in the network. Numerical simulation results are presented to validate the mathematical formulations for the optimization problem, which maximize the energy harvested and the overall throughput rate. Defining the performance metrics of achievable throughput and fairness in resource sharing, the proposed WIPT system outperforms an existing state-of-the-art WIPT system, with the comparison based on numerical simulations of both systems. The improved energy efficiency of the proposed WIPT system contributes to addressing the problem of energy scarcity.

The work presented details the manufacturing of a low-cost hybrid inkjet-printed paper-based potentiostat, with the aim of creating a low-cost sensing system for rapid water quality monitoring. Potentiostats exhibit high sensitivities and can be used for a variety of applications. The results highlight the functionality of a paper-based potentiostat compared to a potentiostat manufactured on a printed circuit board (PCB), an LMP91000EVM development board and a laboratory-based Metrohm Autolab potentiostat. Cyclic voltammetry was performed using an 80 µL sample of 5 mM ferri-ferrocyanide dropped onto a commercial screen-printed electrode from DropSens. The miniaturized paper-based potentiostat is small enough to be stored in a wallet and therefore easy to transport. Furthermore, a cost analysis shows that the potentiostat is 10 times lower in cost than the commercially available handheld potentiostat, taking the costs of man hours into account. This technology enables electrochemistry experiments to be performed on-site using the portable, disposable and low-cost solution and can be applied to a variety of fields including healthcare, wearables and environmental monitoring.