Phenolic compound wastes from a large number of industries big and small which are highly toxic and pose a direct threat to human and aquatic life are generally let into the rivers and coastal waters. 2,4-dichlorophenol is used in the manufacture of industrial and agricultural products such as pesticides, germicides, soil sterilants, seed disinfectants and antiseptics. A modified Rotating Biological Contactor (RBC) was used for the treatability studies of synthetic 2,4-dichlorophenolic (2,4 CP) wastewaters. The RBC used was a four stage laboratory model and the discs were modified by attaching porous netlon sheets to enhance biofilm area and volume. Synthetic wastewaters were prepared with influent concentrations from 40 to 200 mg/l of 2,4 CP. Four hydraulic loads were used in the range of 0.024 to 0.065 m3.m\2.d\1 and the organic loads used were in the range of 2 to 13 g 2,4 CP.m\2.d\1. The RBC was operated at a speed of 12 rpm. Effect of hydraulic loadings and influent 2,4-dichlorophenol concentration on 2,4-dichlorophenol removal were discussed and showed maximum organic removal at hydraulic loads of 0.024 and 0.046 m3.m\2.d\1. Also, a correlation plot between 2,4 CP applied and 2,4 CP removed was presented. A mathematical model was proposed using regression analysis. List of symbols IntroductionOne of the industrial wastes of serious consequence from the point of water pollution is the phenolic compounds wastewater from the manufacture of industrial and agricultural products such as pesticides, germicides, soil sterilants, seed disinfectants and antiseptics. There have been considerable contributions to the knowledge on RBC technology over the last decade. The literature, however, contains limited information on the RBC treatability of toxic organic wastes. There are only a limited number of reports available on the RBC treatment of phenolic industrial wastewaters. Tabak, et al. (1981) studied the biodegradability of 96 compounds using ''static-culture flaskscreening'' method. Even though this method can not be directly compared to the wastewater treatment process, some of the findings are of interest. They found that the chlorinated and nitrated phenols were significantly biodegradable wastes. Tischler and Kocurek (1983) examined the effectiveness of biological treatment in removing toxic organic pollutants from chemical industry wastewaters. Operational data from activated sludge treatment systems operated by five organic chemical manufacturing plants were compiled and evaluated. Sixty toxic organic pollutants including 2,4 dichlorophenol was detected in wastewater samples. The average removal rate was 91%. Congram (1976) studied the treatment of petroleum refinery wastewaters using a 4-stage RBC. He reported that the influent and effluent phenol concentrations were 2.65 and 0.12 mg/l, respectively, which is equivalent to a removal efficiency of 95.5 percent. Huang et al. (1985) studied the RBC treatment of phenol-formaldehyde resin wastewaters. Pilotscale RBCs and various influent phenol levels (in some ca...

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Batch electrocoagulation (EC) experiments were carried out to evaluate the removal of COD and O&G from wastewater using iron electrodes. The effects of operating parameters such as current intensity, initial COD concentration and contact time on COD and O&G removal efficiency had been investigated. It was found that increasing current intensity increased COD and O&G removal efficiency. Initial COD concentration had a little effect on removal efficiencies. Results showed that the COD removal efficiencies after 60 min. was 80.

Filtration is the main process in water treatment plant. In this process the water passing through some porous media (sand) to remove the suspended solids and impurities. In the beginning of filtration process, the head loss is small and it can be easily calculated by different empirical equations, but as the filter bed gets clogged, the head loss increases. The pilot plant was installed in sanitary engineering laboratory, Mansoura University. The operating conditions have five explanatory parameters. These parameters are filter depth, filtration rate, run time, influent turbidity, and alum dose. The filter depth was ranged from 80 to 140 cm and alum dose were ranged from 20 to 50 mg/lit. The rate of filtration was used in the range from 4 to 8 m/hr and the initial turbidities varied from 10 to 50 NTU. A mathematical model was obtained for head loss through deep bed sand filter with various operating conditions (filter depth, filtration rate, alum dose, run time, and initial turbidity).The proposed model yield highly accurate results with correlation coefficient (R 2) of 0.88. The proposed model showed that the most significant parameters on predicted head loss are the run time and filtration rate. Also, the simple proposed model can be easily and effectively used as a decision supporting tool for prediction of filtration run length.