1.0 INTRODUCTION

Wastewater is any water that has been adversely affected in quality by anthropogenic

influence. It compromises liquid waste discharged by domestic residence, commercial

properties, industry, and or agriculture and can encompass a wide range of potential

contaminants and concentrations. In common usage refers the municipal wastewater that

contains a broad spectrum of contaminants resulting from the mixing of wastewater from

different sources. The physical characteristic of wastewater includes its solid content

suspended organic matter, floating matter, and dissolved matter, its temperature, colour,

odour/smell, density, conductivity, specific gravity and specific weight. Basically, the

number of chemicals found in wastewater is limitless. Municipal wastewater also contains a

variety of inorganic substances from domestic and industrial sources, including a number of

potentially toxic elements such as arsenic, cadmium, chromium, copper, lead, mercury and

zinc. Among the organic substances present in sewage are carbohydrates, lignin, fats, soaps,

synthetic detergents, proteins and their decomposition products, as well as various natural and

synthetic organic chemicals from the process industries. Wastewater treatment is a process to

convert wastewater – which is water no longer needed or suitable for its most recent use –

into an effluent that can be either returned to the water cycle with minimal environmental

issues or reused. Treatment means removing impurities from water being treated and some

method of treatment are applicable to both water and wastewater. Before undergo the

wastewater treatment process, the water quality should be determined first. In order to

determine the water quality, we have to refer based on the water parameter which consist of

physical, chemical and also biological characteristic. There are few chemical measures that

can be used to directly detect pollutants and this also can be used to detect imbalance within

the ecosystem. Those are pH, hardness, Dissolved Oxygen (DO), Biochemical Oxygen

Demand (BOD), turbidity, Chemical Oxygen Demand (COD) and many more. Besides that,

we could also determine the water quality based on biological measures. The biological

measures also known as bio monitor defined as an organism that provides quantitative

information on the quality of the environmental around it. It can be deducted through the

study of the content of certain elements or compounds, morphological or cellular structure,

metabolic- biochemical process behaviour or population structure. There are four biological

indicator which are plant indicator, animal indicator and toxin, microbial indicators and last

but not least, macroinvertebrate bio indicators.