Nurdan Buyukkamaci

Economic evaluation of alternative wastewater treatment plant options for pulp and paper industry.

Excessive water consumption in pulp and paper industry results in high amount of wastewater. Pollutant characteristics of the wastewater vary depending on the processes used in production and the quality of paper produced. However, in general, high organic material and suspended solid contents are considered as major pollutants of pulp and paper industry effluents. The major pollutant characteristics of pulp and paper industry effluents in Turkey were surveyed and means of major pollutant concentrations, which were grouped in three different pollution grades (low, moderate and high strength effluents), and flow rates within 3000 to 10,000m(3)/day range with 1000m(3)/day steps were used as design parameters. Ninety-six treatment plants were designed using twelve flow schemes which were combinations of physical treatment, chemical treatment, aerobic and anaerobic biological processes. Detailed comparative cost analysis which includes investment, operation, maintenance and rehabilitation costs was prepared to determine optimum treatment processes for each pollution grade. The most economic and technically optimal treatment processes were found as extended aeration activated sludge process for low strength effluents, extended aeration activated sludge process or UASB followed by an aeration basin for medium strength effluents, and UASB followed by an aeration basin or UASB followed by the conventional activated sludge process for high strength effluents.

Determination of kinetic constants of an anaerobic hybrid reactor

By applying some biokinetic models to data obtained from experimental studies carried out on a laboratory scale anaerobic hybrid model reactor, determination of some kinetic constants of the reactor was aimed. Treatment efficiencies of the model reactor were investigated at different hydraulic retention times (0.5, 1, and 2 days) and organic loading rates (1–10 kgCOD/m3*d). Most suitable models were determined and kinetic parameters were calculated depending on the operational conditions. As a result of the calculations, second-order model and a Stover–Kincannon model were found to be the most appropriate models for the hybrid reactor. The second order substrate removal rate constant (k2(S)) was found as 2.32, 2.57, and 10.81 per day for sludge bed region, fixed bed region, and overall reactor, respectively. Applying the modified Stover–Kincannon model to the fixed bed region of the reactor, the maximum removal rate constant (Umax) and saturation value constant (KB) were found to be 83.3 and 186.23 g l per day, respectively.

Solidification of tannery wastes

Abstract The high chromium concentrations in tannery-wastewater treatment-plant sludges, render them unsuitable for direct disposal. Therefore, one aims to fix the chromium of the tannery waste by adding different additive materials to cause solidification. The properties of the raw sludge were determined and subsequently, the sludge was mixed with cement and additives and left to solidify for 28 days. During the study, 28 different mixtures were prepared and their compressive strengths were determined. Standard elutriation tests were carried out with each solidified sample. Compressive strengths were obtained below the desired concrete strengths. Most of the pollutant parameters in eluate were under the required values.

Concentrated wastewater treatment studies using an anaerobic hybrid reactor

Abstract The treatment performance of an anaerobic hybrid reactor was investigated for different types of concentrated wastewater using a laboratory scale model reactor. Its performance was first examined using synthetic wastewater at different hydraulic retention times (0.5, 1 and 2 days) and organic loading rates (1–10 kg chemical oxygen demand (COD) m −3 per day) over 2 years. COD removal efficiencies ranging from 77 to 90% were achieved. Bakers yeast and meat processing industry wastewater was fed to the model reactor, consecutively. HRT and OLR values were 2 days—9.0 kg COD m −3 per day and 2 days—1.0 kg COD m −3 per day, and about 78 and 75% COD removal efficiency was obtained for yeast and meat industry wastewater, respectively. The methane content of the biogas produced was about 58, 58, and 70% for synthetic, yeast industry and meat processing wastewater, respectively. The organic matter removal efficiency of the reactor indicated that this type of reactor is suitable for treatment of high strength effluent.

Life cycle assessment study on polishing units for use of treated wastewater in agricultural reuse

A life cycle assessment (LCA) approach was used in the assessment of environmental impacts of some polishing units for reuse of wastewater treatment plant effluents in agricultural irrigation. These alternative polishing units were assessed: (1) microfiltration and ultraviolet (UV) disinfection, (2) cartridge filter and ultrafiltration (UF), and (3) just UV disinfection. Two different energy sources, electric grid mix and natural gas, were considered to assess the environmental impacts of them. Afterwards, the effluent of each case was evaluated against the criteria required for irrigation of sensitive crops corresponding to Turkey regulations. Evaluation of environmental impacts was carried out with GaBi 6.1 LCA software. The overall conclusion of this study is that higher electricity consumption causes higher environmental effects. The results of the study revealed that cartridge filter and UF in combination with electric grid mix has the largest impact on the environment for almost all impact categories. In general, the most environmentally friendly solution is UV disinfection. The study revealed environmental impacts for three alternatives drawing attention to the importance of the choice of the most appropriate polishing processes and energy sources for reuse applications.