Dredged material of Izmir harbor: Its behavior and pollution potential

The Arap and Melez Rivers discharge to Izmir Bay bringing wastewater together with rainwater coming from their catchment areas. There is an artificial harbor built at the discharge point of the Melez River acting as a sedimentation area for the suspended matter carried by these rivers. This area has a storage capacity of 3 to 4 years. After this period, the sediments are dredged and disposed from the region. In this study, various studies were carried out in order to determine the geotechnical properties and pollution parameters of the sediments; the results of many previous studies are also given. In the analyses done on dredging samples, it was observed that sulfur, oil and grease, phosphorus, nitrogen and heavy metal concentrations were very high. The reason for these high concentrations is the direct discharge of untreated wastewater formed in the industries located along the Arap and Melez Rivers. The pollutants carried to Izmir Bay by these rivers then settle down inside the artificial harbor and reach high concentrations in bottom sediments. As a result of this study, some possible environmental effects of land disposal of this material are discussed and suggestions are given for final disposal alternatives. © 1995, International Association on Water Quality. All rights reserved

Multipurpose plant systems for renovation of waste waters

WOS: 000244443300004Two promising aquatic macrophytes Lemna minor (Duckweed) and Eichornia crassipes (Water Hyacinth); were used to test their cleaning ability for domestic waste waters in lagoons with one entry point and three outlets in 1996 (floatation rate 110 m(3)/day; BOD(5) 130-170 mg/l; pH 13.5). E. crassipes plants (5+ 5 roots, 25 cm long) were cultured in two lagoons and L. minor in one lagoon. Both species failed to grow due to a high pH. In 1997 the pH of water was neutralized to 6-7 before plant introduction in to the lagoons. L. minor plants did not grow due to overgrowth of rushes. However, E. crassipes grew very well and a total of 3 100 and 3400 roots were counted after 90 days with average heights of 70-75 cm, during this year. These plants showed high absorptive capacity. The dry weight of the harvested plants showed a parallelism to the prevalence with 80.160 kg dry weight. Phenological observations revealed that 80-90% of the plants covering the lagoon surface bloomed and water coming from the outlet became clear enough with a BOD(5) value of 30-40 and 50-80 mg/l. In a later experiment L. minor (20 plants) was cultured in a tank in May 2001 (BOD(5) 130, COD 170, suspended matter 35.2 mg/l). In all 1100 plants/m(2) were counted at the end of 90 days. After harvesting Lemna plants, water analysis showed that BOD(5) was 39.27, total nitrogen content 43, phosphorus 2, potassium 1.67, Pb 0.02, Cd 0.005, and Cr 0.05 mg/l. Renovated and non-renovated waters were used for irrigation of lawns covered by the grass species like Lolium perenne and L. italicum. These species behaved better when sprayed with 100% renovated water than mixed or non-renovated waters