Mehmet Sinan Bilgili

Medical waste management in Turkey: A case study of Istanbul.

The objective of this study was to analyze the present status of medical waste management in the light of the Medical Waste Control Regulation (MWCR) in Istanbul, the largest city in Turkey. About 17% of the hospitals, 20% of bed capacity, and 54% of private hospitals in Turkey are located in Istanbul. The first regulation about medical waste management in Turkey was published in 1993, and as a candidate state, it was changed in 2005 in accordance with EU Environmental Directives. In this work, a survey of 14 questions about the amount, collection, and temporary storage of medical wastes was applied to 192 hospitals in Istanbul through face-to-face interviews. It was found that the estimated quantity of medical waste from the hospitals is about 22tons/day and the average generation rate is 0.63kg/bed-day. Recyclable materials are collected separately at a rate of 83%. Separate collection of different types of wastes is consistently practiced, but 25% of the hospitals still use inappropriate containers for medical waste collection. Almost 77% of the hospitals use appropriate equipment for the medical waste collection personnel. The percentage of the hospitals that have temporary storage depots is 63%. Medical waste management in Istanbul is carried out by applying the MWCR.

Statistical analysis of waste generation in healthcare services: a case study

In the present study, the amounts of medical waste materials, sharps, liquid waste, hazardous waste, household waste and recyclables generated from 375 healthcare services including private hospitals, state hospitals, university hospitals, private medical centres, dialysis centres, cottage hospitals and private dentist surgeries were determined, and the relation between the amount of the waste and the bed capacities, inpatient and outpatient numbers were evaluated. The amount of regulated medical waste corresponded to 28.8% of the total waste streams collected from the healthcare services, and the major producers were private hospitals. The major producers of hazardous waste were state hospitals with a generation rate of 57.9%. The main results of the study indicate that the quantities of the waste streams generated from healthcare services in accordance with the outpatient number gave more appropriate results than the other evaluation methods. Furthermore, evaluation based on the bed capacities gave reasonable results except for recyclables and hazardous waste. As a result of the evaluation of the medical waste generation rate with bed capacities, the generation rate was determined as 2.11 ± 3.83 kg bed-1 day-1 and this rate was 1.45 ± 9.84 kg outpatient-1 day-1 for the evaluation by outpatient numbers. The observed significant P values (P > 0.05) indicate that the evaluation of the waste streams in healthcare services based upon outpatient numbers did not show any reasonable change according to service category.

Modeling 4-Chlorophenol Removal from Aqueous Solutions by Granular Activated Carbon

Since phenols and phenolic compounds in many industrial wastewaters are toxic organic contaminants for humans and aquatic life, to remove these compounds via the most efficient way is very important for environmental remediation treatment. In this context, almost all of the isotherm models (Freundlich, Langmuir, Temkin, Redlich–Peterson, Sips, and Khan) for adsorption in the literature were applied to explain the adsorption mechanism of 4-chlorophenol on activated carbon in this study. Also theoretical modeling data were obtained using model equations; interpolation and analysis of variance were made to compare data by using statistics software. In addition, the thermodynamic and kinetic studies for adsorption mechanism were included in the article. The adsorption of 4-chlorophenol on activated carbon fits well to the pseudo-first-order kinetic model than the pseudo-second-order, intraparticular diffusion and Bangham models. It is also indicated that 4-chlorophenol adsorption by granular activated carbon would be attributed to a type of transition between physical and chemical adsorption rather than a pure physical or chemical adsorption process. As a result, an environmental remediation problem and the adsorption mechanism on activated carbon that can be regarded as a solution to this problem are described and explained using the mathematical models and calculations in this study.

Evaluation of the regulation changes in medical waste management in Turkey

In this study, a survey containing 28 questions concerning general information about the healthcare services, waste collection, training, waste quantities, storage and general evaluation was applied to 311 healthcare services. The response rate was 82%, which was considered acceptable for the evaluation of the results. The separate collection of medical waste and sharps was completely achieved in all of the healthcare services participating in the survey and 82.6% of the healthcare services used containers for separate collection of medical waste. Only 5% of the containers used for waste collection and temporary storage were inappropriate for collecting medical waste. Almost 33% of healthcare services organized courses monthly, 40% quarterly and 20% at least twice a year. A total of 88% of the hospitals have temporary storage depots for medical waste and all of these depots complied with the Medical Waste Control Regulation. The results of this study showed that the medical waste generation rate was 2.35 kg bed-1 day-1. The amount of liquid waste and sharps was determined for the first time in Turkey. The rate of separate collection for recyclables increased to 94%, having been 83% in 2006. The results indicate that in the period 2006—2009, the healthcare services conformed completely to the Medical Waste Control Regulation as it applied. Any deficiencies observed will be satisfied by precautionary actions that will be taken by hospital managers and local administrations.

Process optimization via response surface methodology in the treatment of metal working industry wastewater with electrocoagulation

In this study, process parameters in chemical oxygen demand (COD) and turbidity removal from metal working industry (MWI) wastewater were optimized by electrocoagulation (EC) using aluminum, iron and steel electrodes. The effects of process variables on COD and turbidity were investigated by developing a mathematical model using central composite design method, which is one of the response surface methodologies. Variance analysis was conducted to identify the interaction between process variables and model responses and the optimum conditions for the COD and turbidity removal. Second-order regression models were developed via the Statgraphics Centurion XVI.I software program to predict COD and turbidity removal efficiencies. Under the optimum conditions, removal efficiencies obtained from aluminum electrodes were found to be 76.72% for COD and 99.97% for turbidity, while the removal efficiencies obtained from iron electrodes were found to be 76.55% for COD and 99.9% for turbidity and the removal efficiencies obtained from steel electrodes were found to be 65.75% for COD and 99.25% for turbidity. Operational costs at optimum conditions were found to be 4.83, 1.91 and 2.91 €/m3 for aluminum, iron and steel electrodes, respectively. Iron electrode was found to be more suitable for MWI wastewater treatment in terms of operational cost and treatment efficiency.

Optimization of paper mill industry wastewater treatment by electrocoagulation and electro-Fenton processes using response surface methodology

This study deals with chemical oxygen demand (COD), phenol and Ca+2 removal from paper mill industry wastewater by electrocoagulation (EC) and electro-Fenton (EF) processes. A response surface methodology (RSM) approach was employed to evaluate the effects and interactions of the process variables and to optimize the performance of both processes. Significant quadratic polynomial models were obtained (R2 = 0.959, R2 = 0.993 and R2 = 0.969 for COD, phenol and Ca+2 removal, respectively, for EC and R2 = 0.936, R2 = 0.934 and R2 = 0.890 for COD, phenol and Ca+2 removal, respectively). Numerical optimization based on desirability function was employed; in a 27.55 min trial, 34.7% of COD removal was achieved at pH 9 and current density 96 mA/cm2 for EC, whereas in a 30 min trial, 74.31% of COD removal was achieved at pH 2 and current density 96 mA/cm2 and H2O2/COD molar ratio 2.0 for EF. The operating costs were calculated to be 6.44 €/m3 for EC and 7.02 €/m3 for EF depending on energy and electrode consumption at optimum conditions. The results indicate that the RSM is suitable for the design and optimization of both of the processes. However, EF process was a more effective technology for paper mill industry wastewater treatment as compared with EC.

The impact of nanoparticles on aerobic degradation of municipal solid waste

The amount of nanoparticles released from industrial and consumer products has increased rapidly in the last decade. These products may enter landfills directly or indirectly after the end of their useful life. In order to determine the impact of TiO2 and Ag nanoparticles on aerobic landfilling processes, municipal solid waste was loaded to three pilot-scale aerobic landfill bioreactors (80 cm diameter and 350 cm height) and exposed to TiO2 (AT) and Ag (AA) nanoparticles at total concentrations of 100 mg kg−1 of solid waste. Aerobic landfill bioreactors were operated under the conditions about 0.03 L min−1 kg−1 aeration rate for 250 days, during which the leachate, solid waste, and gas characteristics were measured. The results indicate that there was no significant difference in the leachate characteristics, gas constituents, solid quality parameters, and temperature variations, which are the most important indicators of landfill operations, and overall aerobic degradation performance between the reactors containing TiO2 and Ag nanoparticles, and control (AC) reactor. The data also indicate that the pH levels, ionic strength, and the complex formation capacity of nanoparticles with Cl− ions can reduce the toxicity effects of nanoparticles on aerobic degradation processes. The results suggest that TiO2 and Ag nanoparticles at concentrations of 100 mg kg−1 of solid waste do not have significant impacts on aerobic biological processes and waste management systems.

The Performance of Four Different Mineral Liners on the Transportation of Chlorinated Phenolic Compounds to Groundwater in Landfills

The aim of this study was to investigate the efficiency of four different mineral liners (clay, bentonite, kaoline, and zeolite) which could be utilized to prevent the transport of phenolic compounds to groundwater through alternative liner systems. Four laboratory-scale HDPE reactors with 80 cm height and 40u2009cm inner diameter were operated for a period of 180 days. Results indicated that the transport of mono- or dichlorophenols is significantly prevented by the liner systems used, while the transport of highly chlorinated phenolic compounds cannot be prevented by the landfill liner system effectively. Highly chlorinated phenolic compounds in groundwater can be found in higher concentrations than the leachate, as a result of the degradation and transformation of these compounds. Thus, the analysis of highly chlorinated phenolic compounds such as 2,4,6-TCP, 2,3,6-TCP, 3,4,5-TCP, and PCP is of great significance for the studies to be conducted on the contamination of groundwater around landfills.

Modeling and optimizing Fenton and electro-Fenton processes for dairy wastewater treatment using response surface methodology

In this paper, dairy wastewater treatment was investigated by Fenton and electro-Fenton (EF) processes in respect of removal efficiencies of chemical oxygen demand (COD), orthophosphate, suspended solid (SS), and color. The response surface methodology (RSM) approach using Box–Behnken design was carried out to develop mathematical model and to optimize process parameters. Experimental data were analyzed by the analysis of variance (ANOVA) to identify the interaction mechanism between the process variables and the dependent variables. According to ANOVA results of Fenton process, COD removal increased with an increase in H2O2/COD ratio and reaction time but decreased with increased H2O2/Fe2+ ratio and initial pH. Opposing to that, in the EF process, COD removal increased with an increase in H2O2/Fe2+ ratio and reaction time but decreased with an increase in H2O2/COD ratio and initial pH. The COD removal efficiencies were 65.5 and 72% under the optimum conditions for Fenton (H2O2/COD ratio 1.9, H2O2/Fe2+ ratio 5, pH 4 and reaction time 10xa0min) and electro-Fenton (H2O2/COD ratio 2, current density 32xa0mA/cm2, pH 2.4 and reaction time 45xa0min) processes, respectively. No significant removal differences for orthophosphate, SS and color were determined between the two processes because the removal efficiencies were over the 88% for each process configuration where P value was greater than 5.6u2009*u200910−5 with 99% confidence level and greater than 1.7u2009*u200910−3 with 95% confidence level for all responses for Fenton and EF processes, respectively).

Enhancing filterability of activated sludge from landfill leachate treatment plant by applying electrical field ineffective on bacterial life

The aim of this study is to investigate filterability enhancement of activated sludge supplied form a full-scale leachate treatment plant by applying DC electric field while keeping the biological operational conditions in desirable range. The activated sludge samples were received from the nitrification tank in the leachate treatment plant of Istanbul’s Odayeri Sanitary Landfill Site. Experimental sets were conducted as laboratory-scale batch studies and were duplicated for 1A, 2A, 3A, 4A, and 5A of electrical currents and 2, 5, 10, 15, and 30xa0min of exposure times under continuous aeration. Physicochemical parameters such as temperature, pH, and oxidation reduction potential in the mixture right after each experimental set and biochemical parameters such as chemical oxygen demand, total phosphorus, and ammonia nitrogen in supernatant were analyzed to define the sets that remain in the range of ideal biological operational conditions. Later on, sludge filterability properties such as capillary suction time, specific resistance to filtration, zeta potential, and particle size were measured for remaining harmless sets. Additionally, cost analyses were conducted in respect to energy and electrode consumptions. Application of 2A DC electric field and 15-min exposure time was found to be the most favorable conditions to enhance filterability of the landfill leachate-activated sludge.