Water Quality Monitoring with Arduino Based Sensors

1. Introduction

The Internet of Things, otherwise known as IoT in the simplest sense, refers to the concept of connecting physical devices, machines, software, and objects to the Internet [ 1 ]. In a broader sense, it is a dynamic and global network infrastructure, in which intelligent objects and entities are used in conjunction with actuators, electronics, sensors, software and connectivity to enhance connection, collection and data exchange [ 2 ]. This type of network generally has a large number of nodes that interact with the environment and exchange data, whilst reacting to events or triggering actions to exert control or change upon the physical world. By sharing and acting on shared data contributed by individual parts, an IoT system would be greater than the sum of its parts [ 3 ]. Each network node is considered smart and consumes little resources such as data processing and data storage power as well as energy consumption.

The term Internet of Things was initially coined in 1999 by Kevin Ashton, an expert in digital innovation [ 4 ]. Since then, there has been a significant growth and development in the IoT industry because IoT provides a platform that creates opportunities for people to connect devices and control them with big data technology. Figure 1 below shows the seven industries that are mainly affected by the growth of IoT over the period of late 2014 to early 2017, indicated by the weight which represents the occurrences of investment. The industries affected are namely: Manufacturing, Agriculture, Public Service, Health, Electronics, Energy, and Mining [ 5 ]. IoT integration into manufacturing operations have been repeatedly emphasized by governments using the term Industrial IoT (IIoT) to produce fully intelligent, connected and autonomous manufacturing plants. Agriculture benefits from IoT’s real-time operation for optimizing productivity at reduced costs. A recent study by Cipolla et al. (2019) shows that an IoT system can be used to monitor soil moisture and electrical conductivity, as well as surface and groundwater electrical conductivity, to optimize the management of both irrigation and drainage system [ 6 ]. Installation and monitoring of sensor devices in public services allowed for intelligent transportation system and traffic management, optimal water and electricity management. A water flow driven sensor network can be deployed without much expense and maintenance can be used to reduce the time needed to detect leakage or contamination in urban water distribution systems [ 7 ]. Very low applied risks in IoT implementation in cities are the reason why the Public Service industry is heavily influenced by IoT. Electronics are able to share information through internet connections. Health service can provide better healthcare system and medical data through qualitative analysis in diagnosis.

IoT is not limited to public uses only but can also be used privately. With a central integrated IoT system, the home atmosphere can be adjusted by the pressing of a button, be it temperature, air control, or ambient music. Furthermore, there is the option for smart home security systems which can incorporate cameras, motion detectors, and locks, to notify home owners immediately if the system suspects burglary or intrusion of property. Household IoT systems are able to understand the user’s life habits and appropriately evolve and adapt into a smart housekeeper through constant self-perception and self-checking [ 4 ]. Having all of these features adds convenience, customization, security, and ease of use to life at home [ 8 ].

Evidently, IoT minimizes human efforts in many life aspects whilst promoting efficient resource utilization. It guarantees high speed, accurate quality data with secure processing and better client or user experience [ 9 ]. These imply, amongst other advantages, the reliability and validity of data, performance, security and privacy. Table 1 shows that IoT units are becoming increasingly popular for not just consumer use, but also business and industries and are projected to rise at a steady rate for the coming years [ 10 ].

Lakes and streams are the planet’s most important freshwater system. According to their immediate environments, they are ecosystems and natural life habitats and form part of the food chain from vegetative material to animals to humankind. Rivers are complex life support systems that operate on a thin line of sustainability [ 11 ]. In recent history, the sharp increase in the human population has resulted in a considerable increase in the need for freshwater worldwide. Coupled with other factors such as global warming and anthropogenic inputs (pollution from municipal and industrial wastewater discharge), it is not unbelievable to say that the quality of water is now a major concern for experts around the world. To comprehend the effort and investment needed to obtain fresh drinking water, it is necessary to first understand the fundamental problems faced by freshwater systems.

The quality of surface water is largely affected by natural processes as well as man-made impacts, whereas surface water runoff is a seasonal phenomenon largely affected by climate; anthropogenic discharges represent a constant polluting source to rivers and streams. The Environmental Protection Agency (EPA) attributes Nonpoint Pollution Sources (NPS) as the reason that America’s lakes, rivers and estuaries, in general, remain polluted. Some of the NPS can be prevented, but much of it is a result of the combination of rain, melting snow and irrigation systems [ 12 ]. All three of these events mean that water picks up all types of debris and pollutants in its path to waterways. Water runoff from parking lots, industries, farmlands, and suburb carries oil, gasoline, pesticides, sewage and various other contaminants into water supplies, lakes, rivers and eventually the oceans. Trash, plastic bottles and other refuse also are carried away by floods and rainstorms. These pollutants can have a negative and devastating impact on vegetation and aquatic ecosystems. Thus, activities that can generate NPS include, but are not limited to [ 13 ]:

• Sediment washing from agriculture.

• Deadly viruses and bacteria from animal grazing.

• Construction works.

• Aftermath of natural disasters particularly floods, tornadoes, hurricanes, and tsunamis.

• Gasoline and oil from recreational boating.

• Old and leaky septic systems.

• Urban runoffs from homes and landfills.

• Chemicals from household mismanagement and so on.

Climate and seasons have an effect on the baseflow of rivers and streams. Changing trends in rainfall have contributed to water shortages and affected terrestrial habitats due to variation in precipitation patterns and intensity [ 14 ]. Extreme rainfall may cause disasters such as rainstorms, floods, and erosion, all of which have the ability to alter the natural ecosystem of rivers, streams, and lakes. There is a clear relationship between precipitation and decreased river water quality. The regression models used in reference [ 15 ] have demonstrated that bacteria concentrations increase exponentially with observed precipitation. With heavy rainfalls, it is expected that erosion loss in a freshwater ecosystem would be significant, potentially causing an alteration to the depth of the river bed and to the river flow. Subjectively however, rainfall does not directly influence sediment discharge, but rather the interplay between rainfall and land-use activities affecting sediment production [ 16 ].

What then defines a healthy river? According to [ 17 ], “a biological system can be considered healthy when its inherent potential is realized, its condition is stable, its capacity for self-repair when perturbed is preserved, and minimal external support for management is needed”. Simply put, a river may be defined to be in good condition if its appearance remains stable and is able to rectify any unnatural changes by itself. When conducting water quality monitoring, there are many indicators to choose from. These may be from a biological perspective such as observation of local aquatic life residing in the body of water, or from a physical and chemical perspective such as soil erosion, stream flow, and sediment discharge [ 18 ]. For a small-scale river, measurement of a few important parameters can suffice in giving a general idea to river health.

Currently only few studies exist which investigated ground or surface water in Brunei Darussalam [ 19 20 ]. Results of studies and ongoing monitoring activities have highlighted certain level of pollution in the Brunei River. Possible complex contamination scenarios resulting from this may require a range of remediation and assessment measures [ 21 ]. However, natural occurring microbial processes are able to break down even recalcitrant contaminants [ 22 ].The main sources of pollution have been traced to: effluent and sludge from sewage treatment works within the catchment, sullage waste, solid waste, and direct disposal of sewage from the water village and nearby settlements (50%), surface water runoff from the capital’s central area (29%), and point and nonpoint pollutant loads from various sub-catchment uses, including agricultural, residential and industrial uses [ 23 ]. Under the Tenth National Development Plan, upgrades to existing monitoring systems and quality management frameworks as well as installation of new drainage and sewage systems have been proposed by the government [ 23 ]. However, this does not take away the fact that Brunei does not have a method of active online water quality monitoring. The current scheme of monitoring targets the source water where river water is piped to a treatment plant and samples are collected via sampling tap in the treatment plant’s laboratory. Water quality monitoring results can also be compiled in a database for improved decision making [ 24 ]. Laboratory results take time to be processed and, even then, the results might be inaccurate as certain parameters vary onsite and in-lab. Thus, this study is undertaken to lay the foundation for making advancements in the field of online water quality monitoring.

The main objectives of the study are to develop Internet of Things (IoT) systems, consisting of multiple sensors, communication link, storage and processing capabilities, energy for powering the device, etc., in order to monitor water quality of rivers/streams and also to identify the causes and factors contributing to water quality issues around the vicinity if any. A testing site in Universiti Brunei Darussalam (UBD) has been chosen for the study where the IoT system was placed and monitored directly. Due to financial constraints, the sensors chosen will only focus on the most important parameters. The study took into account the measurement of defined parameters in order to offer real-time online monitoring feedback to users. The data gathered from different IoT sensors would be used in combination with other data to perform data analysis and the results obtained are used to propose preventive measures on how to minimize the impact of pollution. The foundation laid by this study will be kept in order to develop a fully integrated IoT system in the future.

The next section will provide insights on the research component selection, prototype setup, sensor calibrations, and test site selection. Results are given in Section 3 , which is followed by discussions in Section 4 . The final section concludes the paper.