Search results for "Environmental chemistry"
showing 10 items of 3248 documents
Application of Selected Methods of Black Box for Modelling the Settleability Process in Wastewater Treatment Plant
2017
Abstract The paper described how the results of measurements of inflow wastewater temperature in the chamber, a degree of external and internal recirculation in the biological-mechanical wastewater treatment plant (WWTP) in Cedzyna near Kielce, Poland, were used to make predictions of settleability of activated sludge. Three methods, namely: multivariate adaptive regression splines (MARS), random forests (RF) and modified random forests (RF + SOM) were employed to compute activated sludge settleability. The results of analysis indicate that modified random forests demonstrate the best predictive abilities.
Wood pellets for home heating can be considered environmentally friendly fuels? Polycyclic aromatic hydrocarbons (PAHs) in their ashes
2016
This paper reports the results of the first quantitative investigations of PAHs in wood pellet ashes. Investigations were carried out into the fifteen PAHs identified by the US-Environment Protection Agency (US-EPA) as requiring priority monitoring; other non-US-EPA listed PAHs and perylene were also investigated. The total concentrations for the 17 investigated compounds, expressed as the sum of the concentrations (∑PAHs), in the ashes produced by the wood pellet combustion, ranged from 0.064mg kg-1 to 0.90mg kg-1 of dry weight with a means of 0.31mg kg-1. The lowest concentrations (<0.1mg kg-1) were measured in the conifer ash samples. Concentrations of PAHs found in this paper will al…
Determination of Sorption Properties of Heavy Metals in Various Biosorbents
2018
Abstract Various techniques of determination of properties of physicochemical processes of heavy metal sorption in biosorbents were analysed. The methods of preparing and storing samples, conditions of experiment performance, as well as the methods of data interpretation were discussed. Two procedures of study were analysed: (1) in the static system of biosorbent-solution contact and (2) in the system of dynamic flow of solution. Copper cation sorption was studied. The effect of consecutive stages of the study on the quality of final results was shown. A high degree of uncertainty of the sorption capacity assessment was reported, which was dependent on the manner of conducting the study. Th…
Unconventional yeast in the degradation of hydrocarbons in contaminated soil
2018
The influence of Yarrowia lipolytica inoculum on biodegradation of hydrocarbons, and changes in microbiota composition in the soil contaminated with petroleum have been investigated. The material under study was contaminated clay soil, containing petroleum-derived substances at approximately 17 000 [mg/kg d. m.]. Microbiological analysis was carried out by the cultivation method and the content of individual hydrocarbons (n-aliphatic, BTEX and PAHs) was determined by the GC/MS method. The largest decrease of oil-derived substances, versus the control sample, was recorded at the beginning of the process. During the first 30 days, the yeast inoculation caused most effectively removal of n-ali…
The influence of oversizing on maintenance cost in wastewater treatment plants
2021
Abstract Management of Wastewater Treatment Plants (WWTPs) is a complex process, not only from a technical point of view but also from an economic point of view. There are several factors that influence the wastewater treatment process and can cause an increase in management costs. One of these factors is the treatment capacity, in particular the WWTPs’ oversizing problem. The difference between the design population equivalent (p.e.) and the actual p.e. treated generates imbalances in the wastewater treatment process costs. This paper analyses the influence that oversizing has on the maintenance costs for WWTPs in the Valencia region (Spain). Through an econometric approach, the behaviour …
Preventive maintenance versus cost of repairs in asset management: An efficiency analysis in wastewater treatment plants
2020
Abstract The operation and management of Wastewater Treatment Plants (WWTPs) is of paramount importance to guarantee the sustainability of water resources. Just like any other production process, wastewater treatment process involves different costs, such as: energy, personnel, maintenance and reagents. Regarding maintenance costs, they have become an issue of great concern to many operators in the last years. Maintaining the facilities in good condition ensures the proper performance of these infrastructures and reduces the risk of failures. It should be known that equipment breakdowns imply an increase in operating costs, with a high risk of generating an environmental damage due to the m…
Removal of Hexavalent Chromium from Aqueous Solutions Using Biopolymers
2018
AbstractTwo biopolymers were prepared by reaction of chestnut and quebracho tannins with gelatin extracted from untanned hide wastes. Obtained biopolymers were evaluated as adsorbents for removing ...
Exploring relationships between grid cell size and accuracy for debris-flow susceptibility models: a test in the Giampilieri catchment (Sicily, Italy)
2016
Debris flows are among the most hazardous phenomena in nature, requiring the preparation of suscep- tibility models in order to cope with this severe threat. The aim of this research was to verify whether a grid cell-based susceptibility model was capable of predicting the debris- flow initiation sites in the Giampilieri catchment (10 km2), which was hit by a storm on the 1st October 2009, resulting in more than one thousand landslides. This kind of event is to be considered as recurrent in the area as attested by historical data. Therefore, predictive models have been prepared by using forward stepwise binary logistic regression (BLR), a landslide inventory and a set of geo- environmental …
Evaluation of Glyphosate Ecotoxicity and Biodegradability in the Municipal Wastewaters
2018
Glyphosate (G) is a broad-spectrum systemic organophosphate herbicide being widely used to control weeds in agricultural fields and urban areas. Its safety for both human health and aquatic biomes is a subject of wide debate. This study was aimed at evaluating the removal efficiency and ecotoxicity of G based herbicide (GBH) Klinik® (Nufarm, Austria) added to the raw municipal wastewater (WW) in a lab-scale model column system. The effect of oxide ceramics as a filtering medium (treatment „B”), as well as activated sludge and nutrients (treatment „C”) was compared with the control columns, which contained only WW (treatment „A”). After 72h treatment of WW spiked with 100 mg/L G, the lowest …