الفهرس 
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Abstract
The scope of this work includes the treatment of wastewaters from a dye . ’manufacturing plant mainly by coagulation followed by ozonation as well as aeration. , A design and economical study of a modified wastewater treatment unit of the dye , . manufacturing plant is included also in this work.
Since most of the dyestuffs produced by the dye manufacturing plant studied in this research work are water soluble, the total dissolved solids (TDS) present in the wastewater investigated was taken as a measure for the soluble dyestuff present besides the absorbance at different wavelengths.
Both these parameters were chosen as a measure for pollution in the industrial
wastewater under test.
The wastewaters collected from the plant were analyzed and found to have the
following characteristics:
Wastewater (1), trom plant (B), Vat Dyes (sui phonation) showed a pH value of
3.9, tDS of 178qO ppm, absorbance at A..nox. which is 360 nm was 2.704, COD of3620 ppm, BOD of 2220 ppm, settleable solids were found to be 16 cm3 fL and the suspended solids 720 ppm.
Where wastewater (2), trom plant (A), ~o Dyes had a pH value of 6.0, TDS
4550 ppm, absorbance at A..nax. (560 nm) of 1.850, COD 1480 ppm, BOD 1000 ppm, settleable solids were found to be 7 cm3fL and the suspended solids 130 ppm.
The wastewater (3), trom plant (B), Vat Dyes (cWorinaion) showed a pH value of 3.4, IDS 3200, ppm, absorbance at A..nox. (500 nm) was 0.986, COD 1000 ppm, BOD 730 ppm, settleable solids 3.6 cm3fL and suspended solids 180 ppm.
And finally the E. O. P which was prepared by mixing the plant wastewater streams proportional to their flow during 24 hours, had the following characteristics.
pH 5.850, TDS 7840 ppm, absorbance at A..nax. (460 nm) was 2.447, COD 2550 ppm, BOD 1780 ppm, settleable solids 4.5 cm3fL and suspended solids 210 ppm.
In one set of experiments wastewaters (1), (2), (3) and E.O.P were treated with sodium hydroxide (NaOH), calcium hydroxide (Ca(OHh), after coagulation the clear liquor was subjected to ozonation. The results show that the Ca(OHh reduces the TDS, COD, BOD, Settleable Solids, and Suspended Solids more than NaOH.
In the coagulation experiments, the pH of the wastewaters were adjusted tl 8 and 10 and then treated with
- Alum Al2(S04)d 8 H20
- Ferric chloride FeCh
- Calcium carbonate CaC03
- Calcium sulphate CaS04
The results show that the optimum conditions of coagulation, which me; conditions at which maximum reduction of the wastewater characteristics res by coagulation are:
pH = 6 for Alum
pH = 4 for FeCh
pH = 10 for CaC03
And for CaS04 pH = lain the case of wastewater (2) and pH = 8 in the c, wastewater (1) and (3)
The effects of addition of the DrewFlock (polyelectrotyte) to (Na (Ca(OH)2), and the abovementioned coagulants at the optimum conditions studied.
The results show that the addition of the polyelectrolyte improves the treat of the wastewaters with NaOH, Ca(0H)2, and the coagulants with the highest e occuring using CaC03.
After treatment of the wastewaters by coagulation as illustrated before wastewaters were then treated by ozonation and the following variables were studi 1- Current 0.2,0.3,0.4,0.5, and 0.6 Ampere
2- pH 4, 6, 8 and 10
3- Ozone dose 100,200,300, and 400 L, 02/h
4- Time ofozonation 1,2,3,5, 7, 10, 12 and 15 minutes 5- TDS 1000, 1050, 1670, and 1950 ppm
The results show that the optimum conditions of the ozonation process an Ampere, pH = 10, 300 L.02/h and 6 minutes time of ozonation. The design economical study of the wastewater treatment unit based on the resuits obtained f the abovementioned work show the economical and environmental benefits obta from the installation of such a unit.