Three Egyptian industrial wastewater management programmes

A pre-treatment programme for wastewater from factories, representing three main industrial sectors in Egypt, has been developed. The first case study was a factory producing potato-chips. Wastewater discharged from this factory was characterized by high values of BOD, SS and oil and grease (6000 mgO2 l−1, 6577 mg l−1 and 119 mg l−1 respectively). Chemical treatment using lime and lime aided by polyelectrolyte achieved good results. Residual values of BOD and SS after treatment were 97 mg l−1 and 49 mg l−1, respectively. Oil and grease concentrations were reduced by 91 percent. Treatment via activated sludge at a detention time of 4 hrs produced good quality effluent. The second case study was an automobile company, representing the metal finishing industry. Analyses of wastewater samples from the degreasing, phosphating and painting departments, as well as the end-of-pipe effluent were conducted. The end-of-pipe effluent contained high concentrations of oil and grease (366 mg l−1), phosphorous (111 mg l−1) and zinc (81 mg l−1). Chemical treatment of end-of-pipe wastewater using ferric chloride aided by lime, produced high quality effluent. The third sector was the chemical industry. For this purpose a paint factory was selected. Characteristics of raw wastewater varied widely according to the production rate. Average values of COD and BOD were 1950 mg l−1 and 683 mg l−1. Oil and grease ranged from 63 to 1624 mg l−1. Chemical treatment using ferric chloride in combination with lime at the optimum operating conditions achieved good results. Residual values after treatment of COD, BOD and oil and grease reached 120, 36 and 8.6 mg l−1, respectively. An engineering design for each case study has been prepared.