Fresh domestic effluent

Raw urban wastewater is composed of fresh domestic effluent, the quantity and quality of which vary according to time and space (Fig. 1). Two other factors must be considered in order to explain some specific variations rainfall for unitary sewers, and industrial discharges for all types of sewers. 

The evolution of a wastewater UV spectrum is always the same from the source to the discharge after treatment. The shape is always decreasing except for short wavelengths where nitrate formation can lead to high absorption. Another observation to be made 

As the simpler evolution factor of wastewater is certainly due to the presence of particles, it is interesting to study the coarse distribution of their size. A simple experiment can be carried out on a wastewater sample [4], The UV spectrum of the raw sample is compared to the spectra of filtrates obtained after filtration 1 p.m, 0.45 ixm, 0.1 jim, 0.01 p.m (Fig. 3). The effect of the different fractions constituting the colloidal and solid phases can be related to spectra variation, the absorbance of which decreases as the filtration step advances. 

Municipal wastewater is obviously related to the water supply consumption of inhabitants and of municipal and security services (watering, washing). Wastewater flow varies according to the season of the year, weather conditions, day of the week, and time of 

Wastewater flow fluctuations depend on the sewers storage volume and on the time required for the wastewater to reach the treatment plant. Industrial discharges tend to reduce the peak flows. In small communities, two daily peaks are generally observed, while only one is noted in larger cities. In the latter case, the length and complexity of the sewer network tend to smooth the daily flow variation [5], 

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Copper is a one of important trace element required for many biochemical and physiological functions, but excess quantity of this metal in water and food may have undesirable consequences. In accordance with Russian sanitary standai d, general concentration of copper in drinking, fresh, domestic waters and in treated effluent hasn t to be more than 1 mg/1. 

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