معالجة الصرف الصناعى(العلاقة بين التهوية وضبط الاكسجين الكيماوى المذاب)

Aeration

The second set of experiments investigated the organic removal of samples from the third industrial wastewater lagoon inlet that was aerated for two hours after chemically coagulation and precipitation using alum

the COD of the samples without adding coagulant and the COD of the coagulated and settled samples with alum at dose of 100, 150, 200, and 250 ppm.

The COD of the coagulated samples ranged from 390 to 430 ppm, while the COD of the reference sample was about 700 ppm. Increasing the dose of the alum from100 ppm to 250 ppm does not reveled better COD removal

The average COD increase in removal ratio due to the use of alum a coagulant is about 40%.

However

the COD of the samples is still at high concentration. However, the activated sludge system includes recalculated sludge and prolonged aeration time that will help improving the organic matter removal.

CONCLUSIONS
Based upon the experiments results in the study and limited to the conditions determined a prior, the following observations and conclusions could be drawn:

•Using coagulation and sedimentation improve the removal of the colloidal suspended solids form the industrial wastewater.

•Alum and ferrous sulfate showed better turbidity removal than that of the lime and ferric chloride.

•A mixture of alum and ferric chloride removed all the colloidal suspended solids at dose of 200 ppm.

•Using the coagulation and precipitation improve the COD removal by about40%.

•The relatively high coagulants dose and cost may limit the application of the study in the field and study for the treatment inside factories rather than the mixed wastewater is recommende