Serdar Dogruel

Effect of Fenton's oxidation on the particle size distribution of organic carbon in olive mill wastewater

The study evaluated the effect of Fentons oxidation on the particle size distribution (PSD) of significant parameters reflecting the organic carbon content of olive oil mill wastewater (OMW). The organic carbon content of the studied OMW was characterized by a COD level of around 40,000 mg/L, with 13,500 mg/L of TOC and 1670 mg/L of total phenols. The corresponding antioxidant activity (AOA) was determined as 33,400mg/L. PSD of the selected organic carbon parameters was investigated using a sequential filtration/ultrafiltration procedure. COD fractionation based on PSD revealed two major components, a soluble fraction below 2 nm and a particulate fraction above 1600 nm representing 49% and 20% of the total COD, respectively. The remaining COD was distributed in the colloidal and supracolloidal zones. The PSD of TOC, total phenols and AOA exhibited similar profiles with peaks at the two ends of the studied size range. Overall COD removals achieved via Fentons oxidation both at pH=3.0 and pH=4.6 (the original pH of the OMW) remained in the range of 40-50%. As anticipated, the effect of Fentons treatment was more pronounced in the soluble size range. Fentons oxidation at pH=3.0 resulted in 46% and 63% removals for total phenols and AOA, respectively. The results obtained indicated that Fentons process could only be useful as an alternative preliminary treatment option of the required full treatment scheme that could involve a sequence of filtration, oxidation and/or biological treatment steps.

Biodegradation characteristics and size fractionation of landfill leachate for integrated membrane treatment.

The fate of organics and nitrogen during the biological treatment with MBR and subsequent membrane filtration processes (nano filtration, NF; reverse osmosis, RO) were investigated for a landfill leachate. The chemical oxygen demand (COD) and total Kjeldahl nitrogen (TKN) removal performances of membrane bioreactor (MBR) were obtained to be around 89% and 85%, respectively. The effluent COD of MBR was measured to be 1935 mg/L (30 kDa) which is much lower than experimentally determined soluble inert COD of 3200 mg/L using 0.45 μm filter. The readily and slowly biodegradable COD fractions were estimated to be 17% and 52% of raw influent COD, respectively. The respirometry based modeling test performed on raw leachate exhibited much slower degradation kinetics compared to municipal wastewater. A unique subset of model parameters was extracted from batch respirometry by using acclimated MBR sludge. The sequential ultrafiltration (UF) experiments (particle size distribution, PSD) revealed that most of the organics was below 2 nm filter mesh size. In addition, NF/RO post treatment after MBR system was required to increase COD and total nitrogen (TN) removal performances up to 99%. Relatively lower salt rejection rates around 94% was obtained for RO system as a post treatment of MBR system.

Wastewater Reuse for the Minimization of Fresh Water Demand in Coastal Areas—Selected Cases from the Textile Finishing Industry

Abstract Availability of water to the industry often becomes prohibitive, both in terms of quality and cost, in coastal areas. This study takes the textile industry and evaluates the prerequisites of water recovery and reuse. In this context, a large spectrum are studied for their water, the general quality of wastewater generated, quality and treatability of reuse wastewater streams, and expected changes in the overall effluent quality after segregation of the recovery wastewater portion.

Recovery and Reuse in the Textile Industry - A Case Study at a Wool and Blends Finishing Mill

The paper provides experimental justification for a scientific approach to optimizing wastewater recovery and reuse potential in the textile industry. A wool and blends finishing mill, with a high wastewater generation rate, was selected as a case study. A detailed survey was carried out on a selected process to generate a comprehensive pollution profile, which identified a reusable fraction of more than 50%. Chemical settling and oxidation tests were performed to improve the quality of this fraction. COD fractionation and respirometric assessment of biological treatability were evaluated for the wastewater remaining after segregation of the recovered portion, with specific emphasis on the technological implications for appropriate biological treatment.

Biodegradation characteristics of high strength municipal wastewater supported by particle size distribution

Abstract The objective of this study was to evaluate the biodegradability related chemical oxygen demand (COD) fractionation of selected streams from a municipal wastewater treatment plant (MWWTP). The MWWTP under investigation consisted of an activated sludge process which was fed with domestic sewage and pretreated tannery effluents. Another aim was to use particle size distribution (PSD) analysis as a supportive tool for interpreting the effect of primary settling and biological treatment processes on the partitioning of COD fractions over different size categories. The results of conventional characterization and respirometric analyses revealed the strong character of the primary settling tank influent. The high level of soluble inert COD underlined the necessity of an additional treatment step, since the application of biological treatment alone was not adequate to meet the discharge standards. Primary settling removed 35% of the particulate COD, which corresponded to 70% of the initial total COD con...

Effect of ultrasonic and microwave disintegration on physico-chemical and biodegradation characteristics of waste-activated sludge.

ABSTRACT The purpose of this study was to investigate the effect of ultrasonic and microwave disintegration on physico-chemical and biodegradability properties of waste-activated sludge (WAS) from a municipal wastewater treatment plant. Another aim was to carry out particle size distribution (PSD) analysis as an integral component of sludge characterization to highlight the transformation mechanisms involved in pretreatment processes and better understand the biodegradation patterns of sonicated and irradiated WAS liquids examined by means of respirometric measurements. Various combinations of sonication and microwave irradiation parameters were applied to optimize operating conditions. The optimum ultrasonic density was determined as 1.5 W/mL, and energy dosages lower than 30,000 kJ/kg TS resulted in a fairly linear increase in the soluble chemical oxygen demand (SCOD) release. An irradiation time of 10 min and a temperature of 175°C were selected as the optimum microwave pretreatment conditions for sludge liquefaction. The most apparent impact of ultrasonication on the PSD of COD was the shifting of the peak at the particulate fraction (>1600 nm) toward the lowest size range (<2 nm). Microwave heating at the selected experimental conditions and ultrasonic pretreatment at 30,000 kJ/kg TS exhibited comparable size distribution and biodegradation characteristics to those of domestic sewage.

Coagulation-Flocculation of Wastewaters from a Water-Based Paint and Allied Products Industry and its Effect on Inert COD

In this study, treatability of wastewaters generated from a water-based paint and allied products industry has been investigated. As the industry already houses a treatment facility that consists of a coagulation-flocculation unit followed by an activated sludge process, the experimental study focuses on using the existing treatment plant in the most efficient way. In this context the COD removal efficiencies and operating costs of different coagulants i.e., sodium bentonite, alum, FeCl3 and FeSO4 have been evaluated. By assessing the refractory COD content of the subsequent activated sludge system outlet, the coagulant yielding the optimal output has been addressed. The outcomes reveal that the optimum result can be obtained by applying 50 mg L−1 of FeCl3 coagulant at the original pH of the effluent.

Effect of ferric chloride coagulation, lime precipitation, electrocoagulation and the Fenton's reagent on the particle size distribution of olive mill wastewater

Size fractionation of olive mill wastewater (COD:155000 mg/L; TOC:40000 mg/L; BOD5:37700 mg/L; total phenols:4100 mg/L; absorbance at 395 nm:145 cm -1 ) before and after FeCl3 coagulation, Ca(OH)2 precipitation, electrocoagulation and the Fenton process was investigated. Particulate organic compounds were the major components of COD (54%), TOC (43%), BOD5 (43%), absorbance (57%), followed by an appreciable soluble size fraction. For the total phenols parameter, a dominant fraction (54%) appeared in the colloidal (5-8 nm) size range besides significant particulate (22%) and soluble (24%) size fractions. FeCl3 coagulation and Ca(OH)2 precipitation appeared to be most efficient in organic matter removal, whereas electrocoagulation was superior in phenolics removal. No shift in the size distribution pattern was observed after chemical treatment since phase-transfer was the dominant removal mechanism of the selected processes. The highest inhibition of the Vibrio fischeri photobacteria was observed in the particulate size range and decreased in the solube size range due to the elimination of the phenolic

Evaluation of Coagulation-Flocculation on a COD-Based Molecular Size Distribution for a Textile Finishing Mill Effluent

The chemical treatability of wastewaters generated from a textile manufacturing plant performing wool, polyester, wool-polyester blends, woven fabric as well as yarn dyeing and finishing operations was investigated. Coagulation and flocculation experiments were conducted with alum, sodium bentonite and iron salts on wastewaters collected from both the fabric finishing line, after being subjected to in-plant control measures covering water conservation practices and segregation of reusable streams, and dyeing line. The effect of optimum treatment alternatives on the chemical oxygen demand (COD) values of different molecular weight cut-off fractions was also examined.