Ayşen Türkman

Simultaneous biological removal of endosulfan (α+β) and nitrates from drinking waters using wheat straw as substrate

Abstract Nitrate and endosulfan (α+β) removal was studied in an upflow biological denitrification reactor packed with wheat straw as carbon source and support particles for microorganisms. While almost complete nitrate elimination and between 65% and 70% endosulfan (α+β) elimination occurred when the temperature was higher than 20 °C; below that value, nitrate removal efficiency decreased to about 10%. Nitrate, dissolved organic carbon (DOC), and endosulfan (α+β) removal efficiencies decreased considerably at 1500 μg/l endosulfan concentration in the batch experiments. Although a high removal efficiency was observed for endosulfan (α+β) and nitrate in the biological denitrification continuous reactor, the effluent water could not be used for drinking purpose because of the unacceptable levels of endosulfan (α+β), colour and dissolved organic content. During the continuous study, 23.4% of the initial weight of wheat straw was lost and 24 g was consumed per gram of nitrogen removed. The results of the continuous study showed that 21.3% of the endosulfan removal was achieved by adsorption onto the wheat straw and 68.2% of the endosulfan removal occurred by biological activity and the remaining portion was detected in the effluent water.

Cyanide behaviour in soil and groundwater and its control

Results of a bench scale study of the behaviour of cyanide in soil and groundwater are reported and discussed. Effects of chlorination on cyanide were examined and retention capacity of soil was measured. Decay reates for cyanide were determined.

Biodegradation of 4-Chlorophenol in Biosurfactant Supplemented Activated Sludge

Biosurfactants improve the removal of some recalcitrant pollutants in contaminated water and soil. The production and usage of man-made chemicals in industry has led to the entry of any xenobiotics into the environment. One such group of xenobiotics is chlorinated phenols. In this study, the treatment performance of 4-chlorophenol (4-CP), which is one of the most recalcitrant chlorophenols, was investigated using a biosurfactant added activated sludge bioreactor system with changing sludge retention time. Glucose was used as co-substrate and the COD concentration was kept constant during the experiments. JBR 425 rhamnolipid was used as biosurfactant. A control reactor (without biosurfactant; R1) and a test reactors (with biosurfactant addition; R2 and R3) were used in parallel tests. Three lab-scale continuous reactors were run in parallel with the same chemical oxygen demand (COD) and 4-CP loading rates. COD, 4-CP removal efficiencies and biomass concentrations with varying sludge age (3–25 days) were investigated. The effects of food to mass (F/M) ratio on the COD and 4-CP removal efficiencies were also investigated in the reactors. Operation at a sludge age of 3 days resulted in more than 77% COD and 46% 4-CP and 81% COD and 63% 4-CP removals in R2 and R3, while it resulted 61% COD and 19.15% 4-CP removals in R1.

ALTERNATIVE FORMULATIONS FOR THE REUSE OF TREATED WASTEWATER IN MENEMEN PLAIN IRRIGATION SCHEME

In this study, it is intended to investigate the possibility and technical viability of using the effluents of Izmir Wastewater Treatment Plant in Menemen plain irrigation. The research verified the fact that the influent of the plant generally demonstrates typical characteristics of domestic wastewater with the exception of elevated values of electrical conductivity and salinity. These high values are mainly attributed not only to salt water intrusion due to failing pipes and improper pipe connections of the interceptor canal but also to highly-concentrated pre-treated discharges of various industries within the city. It has also been observed that these high values are as well reflected in the plant effluent hindering its use in irrigation. Considering the strong demand for the treatment plant effluent by the farmers and irrigation unions, this study intends to find out possible solutions for high conductivity and salinity. The research involves the formulation of alternative techniques and methodologies such that the quality of treated effluents would satisfy the irrigation water quality criteria currently effective in Turkish legislation.

Algae Removal in Waste Stabilization Ponds

Although waste stabilization ponds are generally considered to be suitable in small communities or for the treatment of industrial wastewaters, there are cases where they are considered to be appropriate for big cities also. They are in use at least 39 countries. They may become feasible if land is available at a low cost. This factor, considerable sunshine and generally warm weather in combination with significant financial advantage in operation forms the basis of feasibility of waste stabilization ponds system in izmir. izmir is the third biggest city of Turkey with its metropolitan population of about two milljon. Among the treatment system alternatives, waste stabilization ponds consisting of three ponds in series has found to be most appropriate for the domestic wastewaters combined with pretreated industrial wastewaters (Figure 1). In this alternate, the wastewaters will be held in anaerobic ponds, facultative ponds, and maturation ponds for 2, 18 and 4 days respectively.

Cancer Risk Assessment in Drinking Water of Izmir, Turkey

In this study, the occurrence of trihalomethanes (THMs) of the tap water in Izmir City was investigated and the lifetime cancer risk of THMs through oral ingestion, dermal absorption, and inhalation exposure were estimated. The total THMs in samples taken from the Tahtali and Balçova Water Treatment Plants (TWTP, BWTP), which are the major water sources of the Izmir City were about 72 and 88 μg/L, respectively. Chloroform existed at the highest concentrations in samples. Although the cancer risk evaluation of CHBr3 through oral route for both sexes was below the EPA level, the highest lifetime cancer risk was originating due to CHCl2Br; 5.2 × 10 −5 and 4.3 × 10−5 for males and 4.76 × 10−5 and 5.8 × 10−5 for females, for the samples from BWTP and TWTP, respectively. While overall the average lifetime cancer risks through oral route, dermal absorption, and inhalation exposure for THMs were higher than the EPA acceptable risk of 10−6 by about 87, 340, and 5.7 times in the samples from TWTP and 99, 390, and 7.9 times in the samples from BWTP, respectively. The average lifetime cancer risk for THMs in both sources was in decreasing order, CHCl2Br, CHCl2Br, CHCL3, and CHBr3 for both sexes.

THE REMOVAL OF NITRATE AND PESTICIDES FROM CONTAMINATED WATER

A water-saturated biological denitrification system was employed to remove selected pesticides and nitrate from drinking waters. In the study, approximately 99% nitrate removal was observed, but most of the samples included nitrite. Up to 95% removal of pesticides was also observed. The lowest removal efficiency of nitrate (63%) was observed when the temperature dropped sharply from 18 C to 14 C. Despite such oscillations, high removal efficiencies for trifluralin, fenitrothion and endosulfan (α+β) were observed and the highest nitrite concentration was 16 mg/l in the effluent of the reactor.