Ayse Filibeli

A Review of Waste Management Options in Olive Oil Production

In this article, treatment and disposal alternatives of olive oil mill wastes and technical requirements for their management are covered. Waste characteristics, treatment options with regard to the economic feasibility, and challenges of existing waste disposal practices in olive growing countries are mentioned. Attention is drawn to present-day techniques of waste management. The search concerning the environmentally acceptable, economically feasible, and practically applicable methods of disposal of olive oil mill wastes is referred. In the management schemes, compliance with environmental regulations and economic and social benefits of the olive oil production are the goals that must be simultaneously achieved.

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.

Disintegration of biological sludge: Effect of ozone oxidation and ultrasonic treatment on aerobic digestibility

The present study deals with disintegration of biological sludge by ozone oxidation and ultrasonic treatment. The effects of ozone and ultrasonic treatment were investigated on aerobic sludge bio-processing as comparatively. 9690kJ/kg TS of specific energy and 0.1g O(3)/kg TS were applied to sludge samples preceding aerobic sludge digestion. In terms of sludge stabilization, the highest volatile solids reduction and protein degradation were obtained with ultrasonic treatment. Moreover, digesters fed with disintegrated sludge had higher bacterial activities in terms of oxygen uptake rate (OUR) and volatile suspended solids (VSS)/ suspended solids (SS) ratio than control one during the operation period. In terms of dewatering characteristics of digested sludge, ultrasonic treatment led to increase the sludges resistance to dewatering. This negative effect was not observed in ozone oxidation. In addition, disintegration processes used in this study did not contribute to an improvement in cake solids on a crown press application.

Aerobic and anaerobic bioprocessing of activated sludge: Floc disintegration by enzymes

Hydrolytic enzymes such as glucosidases, lipases, and proteases have an imperative function at the hydrolysis stage of complex organic structures in the degradation of biodegradable particulate organic matter. As a key factor, extracellular polymeric substances (EPS) control the extracellular hydrolytic enzymes in this degradation mechanism. A flocculated matrix of EPS bridging with bacteria holds back the dewaterability properties of the bioprocessed sludges. Disruption of the flocculated matrix leads to improved solubilization of sludge solids by attacking the hydrolytic enzymes to polymeric substances forming enzyme-substrate complexes. To determine the floc disintegration mechanisms by enzymes during aerobic and anaerobic bioprocessing of sludges, experimental data obtained from three aerobic digesters and three anaerobic digesters were evaluated. As part of a broader project examining the overall fate and effects of hydrolytic enzymes in biological sludge stabilization, this paper compares the performances of aerobic and anaerobic reactors used in this study and reports significant improvements in enzymatic treatment of activated sludge.

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.

Wastewater management for Istanbul: Basis for treatment and disposal

A number of studies have so far been conducted to assess the magnitude of pollution generated by domestic and industrial sources in the Istanbul Metropolitan Area. They indicate that a management scheme for wastewater treatment and disposal should involve a total discharge of 15.4 m3 s(-1) with a potential pollution load of 330 tons BOD5 day(-1) for 1990. A scheme of this magnitude inevitably requires careful evaluation of receiving water characteristics, both from an oceanographic and a quality standpoint. In this paper significant water quality parameters related to the Black Sea-Bosphorus Strait-Marmara Sea System are reviewed and incorporated in the evaluation of treatment and disposal alternatives. In this context, the pollution exchange between the Mamara Sea and Bosphorus is quantified, pollutant contents of the Mamara Sea and discharges from the Istanbul Metropolitan Area are compared, and a number of scenarios are evaluated to define the optimum treatment and disposal strategy.

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.

Rheological Characterization of Sludges during Belt Filtration Dewatering Using an Immobilization Cell

An immobilization cell was successfully coupled to a controlled stress rheometer to quantify rheological properties of a sludge during its dewatering. An anaerobically digested sludge and a synthetic sludge were analyzed and conditioned at various doses with a cationic flocculant. Direct strain-controlled oscillatory analyses could not be performed due to rapid dewatering, but controlled shear rate analysis quantified the increases in sludge viscosity as the solid’s concentration increased. Immobilization times determined by these experiments—viscosity versus dewatering time—agree with capillary suction times, since both indicate the time required for water removal ( r2 from 0.81 to 0.99). However, capillary suction time tests were more strongly influenced by filtrate viscosity at high polymer doses. The immobilization cell allowed quantified amounts of shear to be imposed during dewatering, with greater shearing found to provide more rapid immobilization. This finding is consistent with the design of bel...

Fate of return activated sludge after ozonation: an optimization study for sludge disintegration

The effects of ozonation on sludge disintegration should be investigated before the application of ozone during biological treatment, in order to minimize excess sludge production. In this study, changes in sludge and supernatant after ozonation of return activated sludge were investigated for seven different ozone doses. The optimum ozone dose to avoid inhibition of ozonation and high ozone cost was determined in terms of disintegration degree as 0.05 g O3/gTS. Suspended solid and volatile suspended solid concentrations of sludge decreased by 77.8% and 71.6%, respectively, at the optimum ozone dose. Ozonation significantly decomposed sludge flocs. The release of cell contents was proved by the increase of supernatant total nitrogen (TN) and phosphorus (TP). While TN increased from 7 mg/L to 151 mg/L, TP increased from 8.8 to 33 mg/L at the optimum ozone dose. The dewaterability and filterability characteristics of the ozonated sludge were also examined. Capillary suction time increased with increasing ozone dosage, but specific resistance to filtration increased to a specific value and then decreased dramatically. The particle size distribution changed significantly as a result of floc disruption at an optimum dose of 0.05 g O3/gTS.

Effects of partial ozonation on activated sludge process for the minimization of excess sludge production during biological treatment

AbstractMinimization of excess sludge production may be achieved by either changes in operational conditions or by the treatment of recycled activated sludge. It was investigated using ozone-treated return activated sludge in lab-scale activated sludge process operated continuously with optimum conditions determined using Box–Behnken experimental design method as 400 mg/L initial chemical oxygen demand concentration (CODi), 25 h hydraulic retention time, and 25 d solid retention time, respectively. Batch experiments were carried out in order to determine the optimum ozone dose of 0.05 g O3/g total solid considering disintegration degree (DD). Ozone reactor (OR) and control reactor (CR) were evaluated considering sludge reduction capacity, effluent quality, and sludge characteristics. About 61 and 40% reductions can be achieved in mixed liquor suspended solid concentration and observed sludge yield value in OR compared to CR, respectively. The effluent quality in terms of COD and NH4–N removal in OR was no...