Erdem Görgün

Biological treatability of dairy wastewaters

Biological treatability of an integrated dairy plant wastewater containing a small fraction of whey-washwaters mixture has been experimentally investigated. Emphasis has been placed on the assessment of the initially inert fraction, S1 and soluble residual microbial products, Sp. Parallel batch experiments have been conducted to determine the kinetic and stoichiometric coefficients of the degradable COD. The results have shown that the wastewater tested had practically no initially inert fraction, but generated residual microbial products amounting to 6–7% of the initial degradable COD. The results obtained have been fed into a set of equations describing the steady state operation of an activated sludge system with sludge recycle and a relationship indicating the variation of the total effluent COD with the sludge age has been defined for the wastewater tested. It is noted that effluent COD cannot be biologically reduced below 85 mg l−1, regardless of the sludge age, due to generation of residual fractions.

Model evaluation of temperature dependency for carbon and nitrogen removal in a full-scale activated sludge plant treating leather-tanning wastewater

Organic carbon and nitrogen removal performance of a full-scale activated sludge plant treating pre-settled leather tanning wastewater was evaluated under dynamic process temperatures. Emphasis was placed upon observed nitrogen removal depicting a highly variable magnitude with changing process temperatures. As the plant was not specifically designed for this purpose, observed nitrogen removal could be largely attributed to simultaneous nitrification and denitrification presumably occurring at increased process temperatures (T > 25°C) and resulting low dissolved oxygen levels (DO < 0.5 mgO2/L). Model evaluation using long-term data revealed that the yearly performance of activated sludge reactor could be successfully calibrated by means of temperature dependent parameters associated with nitrification, hydrolysis, ammonification and endogenous decay parameters. In this context, the Arrhenius coefficients of (i) for the maximum autotrophic growth rate, A, (ii) maximum hydrolysis rate, khs and (iii) endogenous heterotrophic decay rate, bH were found to be 1.045, 1.070 and 1.035, respectively. The ammonification rate (ka) defining the degradation of soluble organic nitrogen could not be characterized however via an Arrhenius-type equation.

Wastewater characterization in metropolitan areas with significant agro industries

Basic principles and details on the assessment of wastewater characterization are reported for metropolitan areas with significant industrial activities, with great capacity for future development. The conceptual approach related to the evaluation of pollution loads in terms of major parameters is defined both for domestic and industrial sources. Methods for extrapolating generated data for the future are discussed. A procedure is developed for the evaluation of the expected industrial pollution profiles on the basis of inadequate data. The proposed methodology is illustrated for Corlu as a case study, a region with rapid industrialization in Turkey.

Simulation of nitrogen removal by step feeding for Istanbul wastewaters

The Metropolitan Area of Istanbul is the major polluter in the Marmara Sea which shows all the indications of a sensitive zone. The adopted wastewater management policy involves biological nitrogen and phosphorus removal at all the discharge points in the area. The Riva plant at the Black Sea coast is designed as a two-stage step feeding system. A model simulation shows that the proposed design cannot meet the effluent standard of 10 mgl −1 total N for the sewage character assessed on the basis of an experimental study, totally different from the one adopted for design.

Prioritization methodology of dangerous substances for water quality monitoring with scarce data

Monitoring and control of dangerous substances discharged into receiving waters have attracted more attention lately. Since it is not possible to analyze every single substance, a prioritization methodology is needed for the selection of those to be monitored. Existing well-developed models require significant amount of data for reliable outcomes. This paper presents a methodology to prioritize the dangerous substances having adverse effects on freshwaters in Turkey, where data are scarce. Such a methodology will also serve as a solid model for other countries with limited background data. The adopted methodology enabled the elimination of chemicals to generate a candidate list composed of 608 substances among more than 5000 substances. Further screening and prioritization were conducted using different assessment methods (i.e., Total Hazard Value, Total Impact Value, Combined Monitoring-based, and Modelling-based Priority Setting) to obtain a proposed Final Candidate Specific Pollutants List of 150 dangerous substances. The proposed Candidate National Pollutant List of Turkey was established by combining 45 priority pollutants of the European Union with a list of candidate specific pollutants. According to the outcomes of this study, monitoring and controlling of 195 dangerous substances in freshwaters are recommended. Further detailed studies should be conducted in order to observe the actual levels of these dangerous substances in freshwaters followed by a review of the monitoring list accordingly. Moreover, further revisions might be required in the proposed list due to some possible versatile conditions in terms of sampling points (i.e., change in the location of industries).

Evaluation of inhibition effect of micropollutants on bacterial growth

Eight micropollutants were investigated to determine their inhibition effects on bacterial growth. Both turbidity and suspended solids measurements are used in the inhibition test method. IC50 values defined as the inhibitor concentration which inhibits growth by 50%, were evaluated by using non‐competitive inhibition model and computed K i. constants were coupled to THP system by their rating. As similar to carcinogenity and bioaccumulation effects in the THP system, inhibition effect of micropollutants on bacterial growth is concluded as a new parameter which can be measured quantitatively.

The evaluation of CO2 emissions mitigation scenarios for Turkish electricity sector

This study presents the results on the simulations of the scenarios based on the CO2 emission reduction of the electricity sector in Turkey, utilising the long-range energy alternatives planning (LEAP) system model, and the mitigation costs of the scenarios. Three scenarios including baseline scenario, (scenario 1) and the two mitigation scenarios (scenario 2 and scenario 3) are employed. The scenario 1 is based on the continuation of the recent electricity generation composition. Scenario 2 is established for the evaluation of all the renewable energy potential, except solar, of Turkey while scenario 3 included all the renewable and nuclear energy. The CO2 emission intensity decreased by 20.5% and 35.6% for the scenarios 2 and 3 in 2030, respectively compared to the baseline scenario. The CO2 emission mitigation costs are found 17

The scenario analysis on CO2 emission mitigation potential in the Turkish electricity sector: 2006–2030

/ton CO2 and 40

Evaluation of nitrogen removal by step feeding in large treatment plants

/ton CO2 for the Scenarios 2 and 3, respectively through 2010 to 2030.