*Promising Techniques for Wastewater Treatment and Water Quality Assessment*


#### **Table 1.**

*Sets of some established standards.*

been deduced to be ineffective in environmental monitoring program by both managers and the general public [12]. Carlos and Alejandra [13] argued that providing statements that summarize the water quality data in a simple expressible format that describes the general health or status of a water body is more preferable to environmental managers and the general public rather than been asked to give a rather biased interpretation to complex and technical environmental data. The Water Quality Index (WQI) was first developed by Horton [14] and presents a mathematical method of calculating a single value to represent water quality from multiple water quality parameters. The index represents the level of quality of a water body such as lake, river or stream by using some of the regularly used water parameters (BOD, temperature, turbidity, conductivity etc.) [15]. The WQI is based on the measurement of different water quality parameters thus providing a mechanism for presenting a cumulatively derived numerical expression for defining water quality [16]. The water quality index reduces water quality data to common scale and combines them into a single number in accordance with a chosen method or model of computation. WQI reflects the composite influence of different water quality parameters and is calculated from the point of view of the suitability of both surface and groundwater for intended usage.

The method follows three steps namely:


In order to rank the overall water quality, the Canadian Council of Ministers of Environment CCME [17] established the use of an index that mathematically combines all water quality measures and provides a general and readily understood description of the quality of water. Over the years, many countries have accepted the CCME scheme representing the water quality index for water quality monitoring and assessment of surface and underground water in terms of their chemical, biological and nutrient constituents and overall esthetic condition. The Canadian Council of Ministers of the Environment Water Quality Index (CCME WQI) is

*Application of Water Quality Index for the Assessment of Water from Different Sources… DOI: http://dx.doi.org/10.5772/intechopen.98696*

preferred as a tool for the work due to its simplicity and ability to combine complex water quality data without compromising its technical integrity [16]. The CCME Water Quality Index is considered the most effective method of measuring water quality to determine its suitability for an intended use [18].

In the United States, the US National Foundation uses a weighted linear system of the WQI as a guideline for defining water quality [19]. Many other countries have used the same concepts to define their water quality status including Malaysia [20], Spain [21], Bangladesh [22], and China [23]. The water quality index reduces the bulk number of water parameters used in an assessment and provides a single value. This value is a simplified and logical form that expresses the average quality of water at a specific time based on the analytical values of physico-chemical parameters. This procedure facilitates a simpler and easier interpretation of the data rather than assessing each parameter and allows easy public access and understanding of the water quality data [12, 24, 25].

## **2.4 Merits of the water quality index**

Several advantages and benefits accrue from the use of the water quality index [22] include:


### **2.5 Limitations of the water quality index**

Despite the benefits attributed to the WQI, it is however besieged with some challenges [26, 27], some of which are stated below,

