Study on Industrial Wastewater Characteristics in New Borg El-Arab City, Alexandria, Egypt

Over the past 20 years, the new industrial cities were considered as the main solution to most of the problems facing the metropolitan industrial areas and to assist in the national industrial development. In these new communities, industrial and domestic activities result in the production of vast quantities of wastewater; the improper disposal of which may cause serious environmental hazards. New Borg El-Arab Industrial City (NBA) includes 9 residential areas and 4 industrial zones. The four industrial zones are occupied by 266 running factories belonging to different industrial sectors. All the domestic sewage as well as the industrial wastewater are treated at an oxidation pond treatment plant and the plant effluent is used in irrigation of silviculture areas. The general objective of the present study was to assess the industrial wastewater characteristics. The preassessment phase revealed that 64 factories were discharging industrial wastewater. They could be classified into 9 textile plants, 11 fabricated metal plants, 7 paper and cardboard plants, 12 chemical plants, 23 food industrial plants, and 2 glue plants. The results revealed that out of the 64 wastewater-generating industrial plants in NBA city, 39 were violating the law 93/62 of the wastewater discharge into the sewerage system for one parameter or more. These were 8 textile companies, 5 fabricated metal companies, 4 paper and allied products companies, 7 chemical companies, 12 food processing companies, the studied 2 edible oil refinery companies, and 1 glue production company. The frequency of violation was found to be 59%, 44%, 10%, 56%, 56%, 36%, 10%, and 2.6% as regards pH, SS, settleable solids, BOD, COD, O&G, PO4 , and NH3 respectively among the violating plants. The study proposed some recommendations for the violating companies to comply with the law limits. These were pollution reduction, pretreatment, loans and grants, and awareness and training programmes. 65 JKAU: Met., Env. & Ari Land Agric. Sci., Vol. 16 No. 2, pp: 65-84 (2005 A.D. / 1425 A.H.) M.H. Ramadan et al. 66 Introduction Industry, in its modern sense, has been known in Egypt since the early 19th century. Following World War I, industrial activities based on natural resources began to increase. The concentration of these industries in the metropolitan areas of Cairo, Delta, and Alexandria has put services such as transport, communications, water supply as well as wastewater disposal under special strain. Furthermore, it has led to an imbalance in ecological conditions and a widespread deterioration of environmental quality (Hamza and Gallup, 1982). As a result, new industrial cities (NICs) were represented as the main distinct solution to stop environmental deterioration in the cities of metropolitan areas (World Bank, 1997). Industries make up about 80% of the entire pollution load in wastewater. Industrial and domestic activities result in the production of vast quantities of wastewater. Industries often send their untreated wastewater directly to a municipal facility, paying it to treat them along with municipal wastewater. But industrial effluents sometimes have components that interfere with proper functioning of the municipal plant, or the plant may be unable to remove noxious pollutants and pass them into receiving waters. Also, municipalities often want to use biosolids for beneficial purposes; and the presence of certain industrial pollutants may make these applications impossible or more difficult (Hill, 1977). The New Borg El-Arab (NBA) City is one of the industrial cities in Egypt. It is a part of the Northwestern coastal region of Egypt. It is located at 60 kms from Alexandria and 14 kms from the Mediterranean Sea. The city includes nine residential areas and 4 industrial zones. The 4 industrial zones (I, II, III, and IV) are occupied by 510 factories of different industrial sectors. Most of the residential and industrial zones wastewater in NBA City is served by a network of collecting pipes that carry wastewater to a Waste Stabilization Pond (WSP) treatment plant (Council of NBA, 2002). The study aims at assessing the industrial wastewater characteristics in NBA City. Materials and Methods Within the 4 industrial zones of NBA City, an inventory of the different industrial plants was prepared. A preliminary evaluation visit to each plant was performed in order to prepare an inventory of the wastewater generating companies. These companies constituted the study samples. Samples were collected from the wastewater discharged out of the industrial plants. Sampling was performed six times for each plant. Whenever possible, composite samples were taken. The samples were analyzed physically and chemically according to the Standard Methods for the Examination of Water and Wastewater (Clesceri, et al., 1995). Study on Industrial Wastewater Characteristics in... 67 Results of analyses were compared to the standards mentioned in the decree No. 44/2000, executive decree of law 93/62, for the discharge of industrial waste into the sewerage system (Ministry of Housing and Utilities, 2000). Results and Discussion Results of the Wastewater Audit As a result of the survey, it was found that 266 factories were actually operating. It has been found that 64 factories were producing considerable amounts of wastewater. They are distributed as follows: 16, 31, 16, and 1 factories, in the industrial zones, I, II, III, and IV, respectively. Among the wastewater generating industries, 23 food plants, 12 chemical plants, 11 metal plants, 9 textile plants, 7 paper and allied products plants, and 2 tanning and glue plants. Wastewater Characterization Textile industrial sector From the results presented in Table 1, it is clear that the pH of the wastewater discharged was mostly in the alkaline range, probably from the desizing and bleaching processes. This was in agreement with Snowden-Swan who deduced that the major pollution issue in peroxide bleaching is the high pH (SnowdenSwan, 1995). As for cotton preparation in company [9], no alkali was used and consequently the effluent was almost neutral. Although TDS has no standard value in the decree 44/2002, it could be compared with its corresponding value stated in the previous executive decree No. 9/89 (2000 mg/l). Hence, most companies were found to discharge higher concentrations than that stated in the latter decree. These high TDS contents would not be removed by the present WSP treatment plant. Therefore, they would appear in the final effluent of the ponds thus jeopardizing its suitability for reuse in irrigation, since the Egyptian law No. 92/63 and its executive decree No. 44/ 2000 specify a TDS value of 2000 mg/l. According to the EPA, a typical cotton batch dyeing uses quantities of salt that range from 20% to 80% of the weight of goods dyed, and the usual salt concentration in such wastewater is 2000 to 3000 ppm, with a pH over 10 (USEPA, 1997). This was in accordance with the results of the study since TDS had a mean of 2140 mg/l. The highest BOD5 value was encountered with company [9] (715 mg/l). In addition, COD value was also found to violate the law in the same aforementioned company (1785 mg/l) resulting from the cotton particles reaching the waste stream from raw material washing. Similarly, a COD of 1432 mg/l was determined in the effluent from the raw material storage area in Company [7] where there was very much spillage of dyes and chemicals on the floor. M.H. Ramadan et al. 68 TABLE 1. Physico-chemical analysis of the wastewater discharged from textile companies located in NBA city (1999-2000). Settleable solids ml/l