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Application of Excess Activated Sludge as Waste Sorbent for Dyes Removal from their Aqueous Solutions

Abstract

Organic dyes are widely used in many industries (textiles, food, cosmetics, medicine and biology). These plants produce wastewater containing dyes. Even small amounts of dyes can cause a strong colour of wastewater. Therefore, it is very important to effectively remove residues of these pollutants from the wastewater, before discharging them into the environment. The sorption process is one of the methods used to remove dyes. However this method is often unprofitable economically in comparison with other dye removal processes, due to the high cost of commercial sorbents. Therefore, research is currently conducted in order to find waste materials that can be used as sorbents. The static sorption process of two dyes were carried out (Acid Red 18 and Acid Green 16) with the use of dried excess sludge. The activated sludge (excess) came from a municipal sewage treatment plant that purifies wastewater from carbon, nitrogen and phosphorus compounds. During the study the most favourable pH of the process and the contact time of the sorbent with the dyes were determined. It was observed that for both dyes the highest effectiveness of dye removal was obtained at pH = 2. The most favourable contact time was equal to 60 and 180 minutes for Acid Red 18 and Acid Green 16 respectively. In addition, in order to establish process parameters, a different models of sorption isotherm was examined. The studies showed that the sorption capacity (calculated based on Langmuir model) was much higher in the case of Acid Green 16 (qm = 434.8 mg/g) than for Acid Red 18 (qm = 109.9 mg/g). The experiments to evaluate the effect of pH, contact time on the process effectiveness and to determine the sorption isotherm were conducted at 293.15 K.

Open access
Aspects on Implementation of an Integrated Waste Management System in the Rural Area

Abstract

The issue of waste management in terms of environmental protection is one of the important problems facing humanity, especially in the large agglomeration areas, and in the rural area, the interests are more limited.

The present paper presents theoretical aspects regarding the implementation of an integrated waste management system in the rural area.

Open access
Assessment of Shear Stresses from Shrinkage and Thermal Deformation in Wood-Concrete Bridge Beams

Abstract

The aim of the paper is to assess the values of shear (delaminating) stress in the composition plane between the concrete (RC) deck slab and wood girder from concrete shrinkage, and shrinkage and swelling of wood, as well as difference in temperature between the wood web and concrete slab.

Open access
Assessment of the Efficiency of Biological Treatment of Gases from Municipal Waste Processing

Abstract

The objective of the study is research on a biofilter existing at a mechanical-biological waste treatment plant in Radom. The paper presents results of research on the filling of the analysed biofilter (moisture, organic matter content, nutrient content, pH, grain size composition, and equivalent diameter), process gases (temperature, humidity and pH, concentrations of the main pollutants - ammonia, hydrogen sulphide, volatile organic compounds, acetic acid, ethanol) and operational parameters (flow rate, height of the biofilter layer, surface load, gas residence time in the filter bed). Irregularities were observed related to biofiltration efficiency, particularly resulting from improperly selected filling material and improper biofilter operation. The technological research permitted the identification of problems and determination of the requirement of performing necessary operational changes. Further works will involve the design, manufacture, and installation of an integrated biofilter with two-stage gas purification process (a classic biofilter and a semi-permeable membrane).

Open access
Assessment of the Forest Health Through Remote Sensing Techniques in Valea Roșie Natura 2000 Site, Bihor County, Romania

Abstract

The present study deals with the estimation of the evolution tendency of the environmental stage of a protected habitat with predominant forest vegetation, during a short period of time, using techniques specific to remote sensing. Therefore, two important spectral indexes were tested while assessing the health of the forest ecosystems: i.e. the Normalized Difference Vegetation Index (NDVI) and the Structure Insensitive Pigment Index (SIPI). The period of time taken into consideration for the study was, 2013 - 2019, having used medium resolution satellite photos, Landsat 8 OLI, having initially undergone standard pre-processing operations (resize data, radiometric calibration, atmospheric correction). The satellite images modified according to the Top of Atmosphere Reflectance and corrected topographically resulted into getting values for the two before mentioned indexes. The quantity-spatial results obtained, correlated to the monthly values of the precipitations processed in order to obtain the SPI (Standardized Precipitation Index), mostly reveal, in what SIPI and also NDVI are concerned, a slight decrease in the quality of the forest on the analysed area in the sense that the vegetation stress is increased under meteorological factors, expressed differently depending on the morphometric and pedological parameters of the habitat.

Open access
Benthic Diatoms as Valuable Indicators of Anthropogenic Eutrophication in Biomonitoring of Ribbon Lake

Abstract

In Europe the monitoring of lakes with regard to benthic diatoms is still conducted in line with the European Water Framework Directive. Ribbon lakes are a special case as extremely steep slopes of the lake basin cause their littoral zone to be narrow. The Durowskie ribbon lake was chosen as a model for the assessment of the ecological status of waters based on its Diatom Index. Given its use in recreation, it is under heavy anthropogenic pressure. Physicochemical and biological parameters were monitored in the peak of the vegetational season (July, August) between 2010 and 2018 at 12 varied littoral sites across the full length of the shoreline. This long-term analysis of the Diatom Index, despite showing an improvement in the quality of water, demonstrated the ecological state of Lake Durowskie to be weak (southern, deep part) to moderate (north, shallow part). The taxonomic structure of diatoms (referral and indicator taxa) in phytobenthos communities allowed to show the changes in physicochemical parameters of the environment such as pH, oxygen dissolved in water and its trophic status. Research results are shown in relation to the anthropogenic changes to the lake’s direct catchment area and the results of the physicochemical monitoring of waters.

Open access
Biochar from Maize Hybrid Fermentation Residuelow Cost and Efficient Heavy Metals Sorbent

Abstract

Biochar produced from fermentation residue of maize hybrid was used in untreated form as a sorbent for the removal of Cd(II), Pb(II) and Zn(II) from aqueous solution. The capability of biochar to immobilized ions was investigated by leaching test. Equilibrium between biochar sample and studied elements in solution was reached at a contact time 30 min for Zn(II) and 90 min for Pb(II) and Cd(II). The experimental data were described by pseudofirst-order and pseudo-second-order kinetic model, two- and three-parameter isotherms in non-linear form. The maximum sorption capacity achieved was 30.07 mg·g−1 in the case of Cd(II) ions, 99.44 mg·g−1 in the case of Pb(II) and 40.18 in the case of Zn(II). Biochar developed for this study is comparable to conventional biochar, low cost, non-toxic and experimental results show that is a suitable and efficient sorbent for Cd(II), Pb(II) and Zn(II) removal from aqueous solutions.

Open access
A Brief Review of Robotic Machining

Abstract

The approach of this paper was to analyze the technical borders of industrial robots and to provide an overview of current technology, technical constraints and the potential types of future research suggestion concerning robotic machining. These complex automation machines used in manufacturing processes are an emerging chapter of industrial engineering that contribute to automatically performing operation in subtractive manufacturing and sheet metal forming processes. Compared with CNC machines which have shape limitations and have the restricted working area, the industrial robot is a flexible, cost-saving alternative.

Open access
Building Construction Labour Productivity in Arid Climate Environment

Abstract

Productivity is a significant aspect of construction industry that plays vital role for success and failure of any construction project. This industry generates 11% to 13% of GDP all around the globe and the cost of labour in any building project is 20% to 35% of the cost of Building. On daily basis labour utilizes 30% of time on productive activities rest 70% of the time is ruined in non-productive activities, there are multi factors which are affecting the labour production in construction industry hence this study provides an overview of productivity, Total Factor productivity, method used to measure accurate productivity in construction projects. The objective of this study is find out percentage up to what extent labour production is affected due to weather conditions, however this study is carried out in arid climate region in Month of June 2018, where minimum temperature was recorded 26.0 Celsius degree at 7:30 AM and Maximum was 47.80 Celsius degree at 3:00 PM. A descriptive survey research design approach was adopted using continuous observation method of study. Project work study manual served as the research instrument to collect the data on selected building sites for 30 working days. Data collected were analyzed using descriptive statics. The results show that average monthly production of mason gang was recorded with less production of 28.759%, Carpentry gang with average monthly loss of production 16.74% & steel fixer gang had average monthly loss of production was 12.188. This concludes that prior to signing the contract for construction project. The location, environment, topography of region, capacity of construction operatives must be kept in mind to decide the proper timeline for the successful of project.

Open access
Capability and Maturity. Characteristics Used in Software Reliability Engineering Modeling

Abstract

This paper presents how to use the Capability Maturity Model Integration (CMMI) in software engineering modeling processes. Any variation of CMMI, depending on the scope of application, can also be used to assess the process maturity of an organization. Regarding the Software Reliability Engineering (SRE) process, the activities in the SRE process have been briefly described, noting that the application of SRE in all software-based products leads to good control over the development process.

Open access