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Denim is a cotton fabric specifically used to manufacture jeans. Denim processing generates complex effluents with high levels of pumice stone, color and chemical oxygen demand (COD). There is therefore a need for advanced treatment methods to limit pollution of natural waters. Here, we hypothesized that Fenton oxidation, a method using Fe2+ and H2O2, could replace the traditional step of activated sludge treatment. We studied a daily composite sample at laboratory scale for preliminary settling, chemical settling and Fenton oxidation. We found that pumice stone can be effectively controlled by preliminary settling with partial COD removal and limited color removal. Chemical treatment improved COD removal, but color reduction still remained partial. Fenton oxidation decreased color below visual detection after 5 min and COD decreased to 110 mg/L after 30 min. These findings surpassed the performances of activated sludge treatment.

This paper intended to explore the effect of alkaline H2O2 pretreatment on the biodegradability and the methane generation potential of greenhouse crop waste. A multi-variable experimental design was implemented. In this approach, initial solid content (3–7%), reaction time (6–24 h), H2O2 concentration (1–3%), and reaction temperature (50–100 °C) were varied in different combinations to determine the impact of alkaline H2O2 pretreatment. The results indicated that the alkaline H2O2 pretreatment induced a significant increase in the range of 200–800% in chemical oxygen demand (COD) leakage into the soluble phase, and boosted the methane generation potential from 174 mLCH4/g of volatile solid (VS) to a much higher bracket of 250–350 mLCH4/gVS. Similarly, the lignocellulosic structure of the material was broken down and hydrolyzed by H2O2 dosing, which increased the rate of volatile matter utilization from 31% to 50–70% depending on selected conditions. Alkaline H2O2 pretreatment was optimized to determine optimal conditions for the enhancement of methane generation assuming a cost-driven approach. Optimal alkaline H2O2 pretreatment conditions were found as a reaction temperature of 50 °C, 7% initial solid content, 1% H2O2 concentration, and a reaction time of six h. Under these conditions, the biochemical methane potential (BMP) test yielded as 309 mLCH4/gVS. The enhancement of methane production was calculated as 77.6% compared to raw greenhouse crop wastes.

This study explored the environmental impact of the large-scale projects, the 3rd Bridge across the Bosphorus and 3rd Airport, carried out in the last decade leading to the massive deterioration of the northern forest area in Istanbul. Destroyed forest area was assessed through relevant changes in land classification detected by multi-temporal Landsat data of Istanbul between 2009 and 2016. The magnitude of destroyed carbon stocks and related CO2 emission together with the reduction in the CO2 absorption potential inflicted by massive land-use change were also calculated. Observed results indicated that approximately 15,000 ha of forest area was destroyed in 7 years, corresponding to a 7% ultimate loss in the total forest area. The total land cover change for the same period was determined as 11.5% of the study area. The extent of land cover changes indicated that more than 4.4 million tons of CO2 were additionally emitted to the atmosphere, due to observed reduction of carbon stocks between 2009 and 2016. More than 70% of the total C/CO2 emission associated with land cover changes could be attributed to the loss of forest land. In addition, destroyed forestland corresponded to a CO2 absorption loss of 0.3 million tons CO2/year equivalent to the emission of 830,000 people in Istanbul.

The study evaluated the co-metabolism of nonylphenol polyethoxylate (NPEO) within a main substrate stream subjected to biodegradation in an activated sludge system. Peptone mixture simulating sewage was selected as the synthetic substrate. As a novel approach, the NPEO concentration was magnified to match the COD level of the peptone mixture, so that co-metabolism could be evaluated by respirometry and modeling. A sequencing batch reactor (SBR) set-up at high sludge age to also allow nitrification was operated for this purpose. A long acclimation phase was necessary to start NPEO biodegradation, which was completed with 15% residual by-products. Modeling of respirometric data could identify COD fractions of NPEO with corresponding process kinetics for the first time, where the biodegradation of by-products could be interpreted numerically as a hydrolysis mechanism. Nonylphenol diethoxylate (NP2EO) was observed as the major by-product affecting the biodegradation of NPEO, because NPEO and NP2EO accounted for 60 to 70% of the total soluble COD in the solution during the course of biological reactions. The co-metabolism characteristics basically defined NPEO as a substrate, with no appreciable inhibitory action on the microbial culture both in terms of heterotrophic and autotrophic activities.

A new model for the activated sludge process with membrane separation is presented, based on the effective filtration size. A new size threshold is imposed by the membrane module. The model structure requires a modified fractionation of the chemical oxygen demand and includes chemical oxygen demand fractions entrapped in the reactor or in the flocs as model components. This way, it offers an accurate mechanistic interpretation of microbial mechanisms taking place in membrane activated sludge systems. Denim processing wastewater was selected for model implementation, which emphasized the significance of entrapped fractions of soluble hydrolysable and soluble inert chemical oxygen demand responsible for better effluent quality, while underlining the shortcomings of existing activated sludge models prescribed for systems with conventional gravity settling. The model also introduced particle size distribution analysis as a new experimental instrument complementing respirometric assessments, for an accurate description of chemical oxygen demand fractions with different biodegradation characteristics in related model evaluations.

In the early 1970s, on the basis of the limited scientific data available at the time, a series of master-plan studies concluded that all discharges made to the lower layer of the Bosporus and the Marmara would be transported to the Black Sea, without significant mixing or interference with the upper layer, and consequently with no detrimen- tal effect on the water quality of the Marmara.

A laboratory-scale sequencing batch reactor was started-up with flocculated biomass and operated primarily for enhanced biological phosphate removal. Ten weeks after the start-up, gradual formation of granular sludge was observed. The compact biomass structure allowed halving the settling time, the initial reactor volume, and doubling the influent COD concentration. Continued operation confirmed the possibility of maintaining a stable granular biomass with a sludge volume index less than 40 ml g-1, while securing a removal efficiency of 95% for carbon, 99.6% for phosphate, and 71% for nitrogen. Microscopic observations revealed a morphological diversity.

This study aims to establish the scientific link between the livestock wastes and energy recovery processes to implement the most appropriate technology at the highest economic benefit. The evaluation was based on the recovery of the potential energy of the mixture of four livestock wastes (cattle, sheep, goat, egg chicken) by four different energy recovery processes. Incineration, gasification, pyrolysis at 550°C and 750°C were applied as thermal processes together with the anaerobic digestion as biochemical process. The recovery performance of each process was evaluated within a defined design algorithm considering all significant parameters in seven geographical regions and in Turkey as a whole. Incineration seems to be the most efficient energy recovery process with 0.43 MWe/t for Turkey. Gasification took the second place in the energy recovery ranking with 0.34 MWe/t, 21% less than incineration. Pyrolysis expressed an energy recovery rate of 0.15 MWe/t at 550°C and a twice higher rate at 750°C, at a level close to gasification. Anaerobic digestion exerted a recovery potential of 0.21 MWe/t for the livestock waste considered. Energy recovery from livestock waste not only contributes to energy production, but also provides compliance with the concept of reducing emissions and sustainable environment.

The potential of a recently isolated wood-degrading fungus, Trichophyton rubrum LSK-27, for effective decolorization of textile azo dyes was evaluated. Within two days of dye addition, the fungus was able to decolorize 83% of Remazol Tiefschwarz, 86% of Remazol Blue RR and 80% of Supranol Turquoise GGL in liquid cultures. The reactive dyes, Remazol Tiefschwarz and Remazol Blue, were removed by fungal biodegradation, while decolorization of the acid dye, Supranol Turquoise GGL, was accomplished mainly by bioadsorption. Therefore the fungus proved to be efficiently capable of both biodegradation and biosorption as the major dye removal mechanisms. The extent of biodegradation was associated with the levels of the extracellular ligninolytic enzymes such as manganese peroxidase and laccase.[PUBLICATION ABSTRACT]