Geospatial alternatives for quantification of bio-thermal influence zone in the vicinity of a solid waste dump.

Owing to the release of toxic gases, leachate and thermal emissions that originate from waste dumps, these sites significantly impact environmental sustainability. The study attempts to assess the deleterious impact of municipal solid waste (MSW) dump on surrounding forested landscape by employing geospatial technologies, which are cost and time-effective. For this purpose, temporal period ranging from 2015 to 2020, having 41 valid satellite observations has been selected for study. Firstly, the radii of intense hazardous zone and hazardous zone have been measured, as two separate parameters, which are 580 ± 30 m and 1260 ± 30 m, respectively. Secondly, average spatial extent of bio-influence zone is measured to be 1262 m while the average thermal influence zone extends up to 530 m around the MSW dumping site. A detailed analysis of influence zone variations reveals that the bio-influence zone depends on multitude of meteorological parameters, whereas the thermal influence zone relies mainly on seasonal temperature fluctuations. Moreover, the level of severity of emissions from MSW decomposition directly depends upon temperature. The long-term variability analysis of these hazardous zones reveals the stationarity of their spatial extents, signifying forest resilience. This study has proved significance of geospatial techniques as an alternate of expensive and time intensive assessment methods involving in situ measurements. So the proposed technique is beneficial for environmentalists, decision-makers and municipal authorities for analysing the extent and severity of MSW pollutants for forest community to address the problem of ecological degradation.

Treatment of hospital wastewater by supercritical water oxidation process.

Hospital wastewater contains several micro and macro pollutants that cannot be removed efficiently by conventional treatment processes. Thus, generally hybrid and multistage treatment methods are suggested for the treatment of hospital wastewater. Supercritical water oxidation (SCWO) is a promising method for the removal of emerging organic pollutants from hospital wastewater in one step and a very short reaction time. In this study, supercritical water oxidation (SCWO) process was used for the removal of pharmaceuticals in addition to conventional pollutants from real hospital wastewater. As a result of a series of preliminary studies, the optimum conditions were selected as 450 °C, 60 s, and 1:1 for temperature, reaction time, and oxidant ratio (H2O2/COD), respectively, for the treatment of hospital wastewater at 25 ± 1 MPa. The removal rates were determined above 90% for COD, BOD, TOC, TN, and SS from hospital wastewater. Phosphorus removal was greater than 90%, while the removal rates were around 80% for phenol, AOX, and surfactants in hospital wastewater. A total of 9 pharmaceuticals were observed in the real hospital wastewater samples. The highest removal rate was obtained for Paracetamol as 99.9%, while the lowest removal rate was obtained for Warfarin as 72% after SCWO treatment of hospital wastewater. As a result, it can be concluded that SCWO process is sufficient for the treatment of hospital wastewater without the need of additional treatment steps, with high removal rates in a short reaction time.

Prioritization of the treatment and disposal methods of wastes containing polychlorinated biphenyl by fuzzy multi-criteria decision-making and risk assessment.

A total of 209 different types of polychlorinated biphenyls (PCBs) with various properties have been produced from 1930 to 1970s in which they have been banned due to their toxic effects. Total produced PCBs in the world are around 15 to 20 million tons, and up to now, 5.4 million tons of PCB-containing or PCB-contaminated equipment/materials has been eliminated. The remaining 10-15 million tons still needs to be removed or managed. Moreover, PCBs are pollutants still being unintentionally formed. These pollutants can be treated or disposed of various methods. However, there is a lack of knowledge about the selection of the treatment and disposal methods and their environmental, technological, cost, and social/ergonomic evaluation perspectives and the risk assessment during method selection. In this study, a projection was presented for the management of PCBs with an integrated multi-criteria decision-making (MCDM)-risk analysis focusing on these questions. Treatment (physical, chemical, biological) and disposal (incineration, landfill, supercritical water oxidation/gasification (SCWO/G), and pyrolysis/gasification) methods for the management of PCB-containing waste have been prioritized by fuzzy-analytical hierarchy process (F-AHP) in terms of environmental, technology, cost, and social/ergonomic criteria. Risk analysis was also made in terms of these criteria for considered alternatives, and compliance with risk and MCDM was evaluated. As a result of the study, priority methods among alternatives were determined as chemical treatment and SCWO/G. It has been determined that the weight values of the main criteria of environmental, technology, cost, and social/ergonomics were close to each other, but the emission criterion of the sub-criteria was determined to be of higher priority. In the risk analysis, chemical treatment and SCWO/G methods have been found to carry a more acceptable risk. Thus, it has been evaluated that these methods provide more superiority than other methods.

Characterisation of wastes collected from beaches, coastlines, marine surface cleaning processes and ships: A case study of Istanbul.

Marine waste management is crucial for Istanbul because of the significant location for intercontinental transition, international trade, tourism, industry and shipping. This study is the first one realised in Turkey for the detailed characterisation of marine waste. The amount and characteristics of solid wastes originating from beaches, coastlines, sea surface cleaning processes and ships (both cargo and cruise ships) were determined. It was observed that marine wastes includes a significant amount of recyclable materials. Although, it was ascertained that the amount and composition of waste differs according to the collecting sources, the majority of wastes are composed of different types of plastics. The average calorific value of marine waste was determined as 2500 kcal kg-1, which is higher than that of mixed municipal solid waste. There is a lack of studies on the pathways of disposal alternatives of marine waste after collection. As landfilling is the common pathway for disposal after collecting, it is clear that recycle/reuse and energy recovery options are possible for marine waste.

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.

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 30 min 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.

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.

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 40 cm 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.

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.

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.

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.