Livestock slaughterhouses waste management in urban environment

The current study presents an investigation on the waste management in the cattle slaughterhouse by the following objectives: a) to identify the existing waste management practices in relation to sources, quantity and characteristic of wastes; b) to identify the situation of production, collection, storage, transportation, processing and recycling, and final disposal of wastes and the problems of existing waste management practices. In order to obtain reliable information and filling the check list, site surveys were conducted when the management of the slaughter-house was interviewed in waste management practices. The total produced industrial waste in studying units' was found to be 10252 tons/year. The per capita waste generations were reported to be 54.6 kg/cattle/day and 11.1 kg/sheep/day. Also, more than 98% of the hazardous waste produced can be infectious. However, it is important to keep in mind that setting an operational program and careful monitoring of its optimal execution by the slaughterhouse manager is necessary. Consequently, findings provide useful inputs for decision making processes around construction slaughterhouses waste management.  </strong

The treatment of printing and packaging wastewater by electrocoagulation– flotation: the simultaneous efficacy of critical parameters and economics

In this work, electrocoagulation–flotation (ECF) following sedimentation was applied as a printing and packaging wastewater treatment using four Al electrodes with a parallel monopolar configuration. A sedimentation process was applied after the ECF as a post-treatment phase to remove large pollutants. The simultaneous efficacy of the operating parameters initial color content (1,843.44–12,156.56 ADMI), initial pH (3.56–10.44), current density (6.02–22.18 mA/cm2), and treatment time (5.62–74.38 min) on color and chemical oxygen demand (COD) removal efficiencies were evaluated alongside processing costs. Response surface methodology (RSM) and central composite design (CCD) optimized these key parameters to achieve the highest removal efficiencies and lowest operating costs. Based on the results analyzed by RSM-CCD, using initial color content of 5,576.38 ADMI, initial pH of 7.29, the current density of 18.49 mA/cm2, and treatment time of 59.76 min as optimum operational conditions can result in 97.8% and 92.1% for color and COD removal efficiencies, respectively. At these optimum conditions, operating costs (OPCs), including electrodes material and energy consumption, were 0.07 US$/(kg color removed) and 0.4 US$/(kg COD removed). The results confirm ECF-sedimentation as a promising and costeffective tool for the treatment of printing and packaging wastewater

An investigation on hospital solid waste management in Iran

The integrated hospital solid waste management emphasizes the need to conduct a survey based on a standardized method that equally be analyzed at national level. This study aimed to test the usability of a national tool to do integration data analysis of hospital waste management status. Then, a typical study was conducted in Karaj hospitals. Also, critical analysis of hospital�s solid waste management aspects was done, and shortcomings in the aspects were identified. The pilot study results showed that the daily per capita waste generations were reported to be 4.2±0.49 kg/available bed, 5.8±0.63 kg/occupied bed, and 10.3±0.9 kg/inpatient. The names of the hospitals were omitted when they were named from H1 to H8. So the highest and lowest daily waste generation rate were 5.5±0.35 and 2.6±0.78 kg/available bed in H7 and H3 hospitals, respectively. In this study, total infectious wastes per capita were reported to be 2.3±0.39 kg/available bed/day, 3±0.5 kg/occupied bed/day and 5.2±0.84 kg/inpatient/day. Furthermore, the averages per capita of total general waste were 2±0.4 kg/available bed/day, 2.8±0.51 kg/occupied bed/day and 5.1±0.8 kg/inpatient/day. Analysis of the Karaj hospital waste management status showed statue of hospital waste management in 88 of hospitals were ranked moderate when others were achieved to be poor by 12. The hospital waste management had been evaluated poor in term of collection, transportation and manpower aspects, moderate in the separation and temporary storage aspects and good in the disposal aspect. It was also found that the MOHME tool is appropriate tool to investigate the status of waste management in hospitals. © 2015 Global NEST Printed in Greece. All rights reserved

The influence of thermal and visible light activation modes on the NO2 response of WO3 nanofibers prepared by electrospinning

The paper reports on the influence of visible light at different wavelengths (red, λ = 630 nm; green, λ = 570 nm; purple–blue, λ = 430 nm), light irradiance conditions (from 30 to 770 μW/cm2) and operating temperatures (from 25 °C to 100 °C) on the electrical response of WO3 electrospun nanofibers (NFs) to 100–400 ppb NO2 gas in dry air. WO3 NFs were prepared by mixing a W–O sol–gel transparent solution (WCl6 in ethanol) with a polymeric solution made of polyvinylpyrrolidone (PVP) and dimethylformamide (DMF). Electrospun NFs were annealed between 300 °C and 500 °C and the their microstructures features investigated by SEM and XRD. Room temperature (25 °C) gas responses of the 450 °C annealed NFs have shown that, beside a slight reduction of the relative gas response (RRs), a decrease of the light wavelength (toward the purple–blue) and an increase of its irradiance, greatly improve the base line recovery and the response time with respect to dark conditions. At operating temperatures ranging from 25 °C to 100 °C, sensor relative responses in dark always resulted to be higher as respect to the ones displayed under purple–blue light illumination. The combined action of purple-blue light with an irradiance of 770 μW/cm2 and of mild operating temperature of 75 °C, relative responses (RRs) of 12.4 and base line recovery percentages (RPs) of 97% were attained at 400 ppb NO2. The capability to tune the response of WO3 NFs to NO2 by combining light and mild thermal gas sensors activations is addressed and discussed also considering the involved response mechanisms

A systematic diagnosis of state of the art in the use of electrocoagulation as a sustainable technology for pollutant treatment: An updated review

Electrocoagulation (EC) and electrocoagulation-flotation (ECF) are of widespread interest owing to their effectiveness for the simultaneous abatement of a broad range of pollutants in drinking and waste waters, but their capability can vary significantly depending on the operating conditions. The effect of operating conditions on the performance of EC has been the subject of much debate over the last few decades. This review aims to focus on the application of EC/ECF processes for pollutants removal under different operating conditions, emphasizing the principal issues that compose the foundation of EC/ECF. It has been found that the current density (typically 1–20 mA/cm2), type of electrode (Al or Fe), and electrolysis time are the key process parameters that influence performance. Although some key mechanisms of pollutant abatement in EC/ECF processes have been identified, recent studies have begun to reveal how the underlying removal mechanisms using the EC/ECF processes depend on the nature of pollutant. Key mechanisms of pollutant abatement include charge neutralization, reduction– oxidation, and precipitation/co-precipitation. The development of improved or innovative cell designs, as well as systematic modeling of EC reactors, are needed. Future research focused on hybrid technologies with cost-effective energy supply may lead to innovative treatment options for wastewater treatment

Electrocoagulation as a promising defluoridation technology from water: A review of state of the art of removal mechanisms and performance trends

Fluoride ions present in drinking water are beneficial to human health when at proper concentration levels (0.5-1.5 mg L-1), but an excess intake of fluoride (>1.5 mg L-1) may pose several health problems. In this context, reducing high fluoride concentrations in water is a major worldwide challenge. The World Health Organization has recommended setting a permissible limit of 1.5 mg L-1. The application of electrocoagulation (EC) processes has received widespread and increasing attention as a promising treatment technology and a competitive treatment for fluoride control. EC technology has been favourably applied due to its economic effectiveness, environmental versatility, amenability of automation, and low sludge production. This review provides more detailed information on fluoride removal from water by the EC process, including operating parameters, removal mechanisms, energy consumption, and operating costs. Additionally, it also focuses attention on future trends related to improve defluoridation efficiency. © 2021 by the authors. Licensee MDPI, Basel, Switzerland