What is a sample? In term of environmental control, a sample is part of the physical environment taken for physical or chemical analysis. The purpose of sampling is to collect the volume of a water body (or another subject such as soil, air) or processing unit, which will be examined, with the smallest number possible but still representative that still has the same properties as whole water bodies or water and waste treatment units.
The requirements in the environmental analysis are as follows:
- Sampling is representative
- Good sample transportation and good sample preservation
- Proper physical and chemical analysis of the sample
The results of the analysis in the laboratory are used to calculate main two parameters that provide an assessment of the state of water bodies under study, namely:
The concentration should be known to provide information about how worse the waste contained in the environment. As well as how bad the deviation of environmental quality to the standard
- Pollution load
The load of the polluter is the main information for operational planning (operating unit) on the installation of drinking water and wastewater disposal. As well as how is whole environment system can accept the waste.
Generally, samples can be grouped into three types: discrete, integrated, and composite sample. First, discrete samples will be described as following:
- Discrete Samples
Represents the volume of samples taken directly from the body of water under investigation. Instantaneous sample values represent only the flow of water at a point in time only. Instantaneous sampling can be taken only if the liquid waste meets any of the following conditions:
a. Constant relative characteristics for such span or a certain range, for examples:
– The sampling of waste samples in effluent equalization tanks which are theoretically constant.
– The Sampling on the liquid waste in the aeration tank.
– The sampling of standard liquid waste from an industry whose production processes are constant.
b. The rate of water is not continuous and disconnected (discrete), for examples:
– The sampling of a one-time production process.
– Sampling on Unit Sequencing Batch Reactor that works is not continuous.
– Unstable liquid waste characteristics or there is extraordinary/emergency situation.