الفهرس 
acknowledgementOnly 14 pages are availabe for public view
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Abstract
According to the master plan of Alexandria Metropolitan area the industrial waste will be collected with the domestic waste and their combined treatment is recornmended a head of their final disposal either on land for agriculture purpose or to the sea. There are two waste treatment plants in the Alexandria wastewater master plan study. It may be overseen that treatment of liquid waste of Alexandria City is a national object; extra-ordinary sewage effluents which con tain different proportions of industrial waste that render them abnor mal wastes are lacking sufficient studies to: i- Detect the ability of these wastes to undergo biological treatment. i1- Find their effect on the ability of domestic wastes, with which they are mixed, to undergo treatment. iii- Determine the fate of the abno~nal pollutants in industrial wastes during and after being treated. A study of the factors affecting the activated sludge process is needed at this time to relate operation conditions with the efficiency of the biological treatment plants receiving combined wastes. a) Using the manometric BOD apparatus batch experiments were carried out to study the effect of metal ions (chromium trivalent and hexa valent, zinc, copper, mercury. iron), organic compounds (phenol, . aniline, benzoic acid, salicylic acid, p-amino benzoic acid, p-amino phenol) and the hydrogen ion concentration on the BOD value and ki netics of reactions. The rate of reaction decreased with the lowering and raising of pH from normal, however when the pH was raised to 10.7 or higher the reaction stopped completely. It was observed that the order of the reaction changed from first order for the reference run to zero order in the acidic runs. However in the alkaline runs the reaction followed an almost first order equation till pH lower than 10.0. Organic contaminants were tolerated by the system up to certain concentrations without affecting the reaction order. Some of them e.g. phenol and its derivatives proved to be degraded by the system where the overall oxygen uptake increased. Increasing the concen tration of certain organic contaminants e.g. benzoic acid over cer tain limits retarded the reaction and shifted it to the zero order equation. Most heavy metals exhibit a toxic effect by increasing its concen trations and the total oxygen uptakes decreased in comparison with the reference run. In the application of Michaelis and Monod equation the Km was almost zero for all the organics and some of th~ metals while Vmax. was small (0.8-5.6). This proved a state of non competitive inhi bition. In case of copper, iron, and hexavalent chromium the Vmax. never reaclled its highest limits Wllich showed a feedback inhibition state. b) Bench scale continuous activated sludge experiments were carried out to examine the feasibility of using acclimated activated sludge to treat combined wastes. The acclimation was done using different concentrations of toxic ingredients in a mixed modified synthetic sewage. For wastes of different pHIs, on the alkaline side, the system can tolerate a stronger alkali than a weaker alkali at the same pH, but on the acid side the system can tolerate a weaker acid than a stron gel’ acid. Acclimated activated sludge system proved to be efficient in the biodegradation of combined wastes containing heavy metals exerting an inhibitory effect on batch experiments.(i.e.) after acclimation, higher concentrations of metal ion can be tolerated. The increase of organic load did not affect the removal efficien cy of BOD in case of chromium hexavalent, while there was a slight improvement in the BOD removal in case of chromium trivalent. TI~ range of sludg~ volume index obtained for chromium trivalent indicated a good settleability. In case of chromium hexavalent the sludge volume index was almost constant as the removal of chromium hexavalent was not achieved in the aeration tank. Sludge was pro duced in case of chromium trivalent while sludge production decrea sed in case of chromium hexavalent according to the correlation parameter 8 which was positive with the chromium trivalent (0.42) and negative with chromium hexavalent (-0.088). The endogenous metabolism defined by the coefficient b, was high in case of Cr+6 (0.036) where the accumulation of nonbiodegradable mass reduced the percentage of active organisms present in the system. c) The measurements and de terminations of characteristics of wastewater from the different units of the El Nasr Leather Tanning Company and slaughter house indicated that the tannery wastes were one of the concentrated and most troublesome wastes. The application of such concentrated waste on the bench scale continuous activated sludge model resulted in excessive foaming. It was therefore necessary to pretreat the waste by settling and diluting it from 1 to 2 before feeding to the aeration vessel. The BOD reductions were in the order of 83while COD reductions were less. The treated waste was free from sulfide and chromium which were removed by the system. Finally, it may be concluded that the acclimated activated sludge system may tolerate to a great extent the domestic wastes containing different concentration of inhibitors or toxicants whether organics or heavy metals. Also this system proved to be efficient in reducing the pollutional load of the tannery wastes.