Search results for "wage"

Estimation of the environmental hazard of organochlorines in pulp mill biosludge used as soil fertilizer

1993

Abstract Contents of total organic chlorine and polychlorinated phenols, guaiacols, catechols, benzenes, cymenes, cymenenes, naphthalenes, toxic dibenzodioxins, toxic dibenzofurans, toxic PCB congener 77, alkylated dibenzofurans, alkylated bibenzyls and alkylated phenanthrenes in spent biosludges from activated sludge treatment plants of chlorobleaching kraft pulp mills are reported. Some estimations of hazard caused by these organochlorines to humans and wildlife from the use of biosludge as soil fertilizer are constructed and discussed.

Importance of ligand speciation in environmental research:A case study

2001

The speciations of EDTA and DTPA in process, waste and river waters are modelled and simulated, specifically to the mode of occurrence in the pulp and paper mill effluents and subsequently in receiving waters. Due to relatively short residence times in bleaching process and waste water treatment and slow exchange kinetics, it is expected that the thermodynamic equilibrium is not necessarily reached. Therefore, the initial speciation plays a key role. As such, the simulations have been extended to the process waters of the pulp and paper industry taking into account estimated average conditions. The results reveal that the main species are; Mn and Ca complexes of EDTA and DTPA in pulp mill p…

Modeling of anaerobic degradation of solid slaughterhouse waste: inhibition effects of long-chain fatty acids or ammonia.

2003

The anaerobic bioconversion of solid poultry slaughterhouse wastes was kinetically investigated. The modified version ofMETHANEsimulation model was applied for description of experimental data in mesophilic laboratory digester and assays. Additionally, stages of formation and consumption of long chain fatty acids (LCFA) were included in the model. Batch data on volatile solids, ammonium, acetate, butyrate, propionate, LCFA concentrations, pH level, cumulative volume, and methane partial pressure were used for model calibration. As a reference, the model was used to describe digestion of solid sorted household waste. Simulation results showed that an inhibition of polymer hydrolysis by volat…

Uncertainty in urban stormwater quality modelling: The influence of likelihood measure formulation in the GLUE methodology

2009

In the last years, the attention on integrated analysis of sewer networks, wastewater treatment plants and receiving waters has been growing. However, the common lack of data in the urban water-quality field and the incomplete knowledge regarding the interpretation of the main phenomena taking part in integrated urban water systems draw attention to the necessity of evaluating the reliability of model results. Uncertainty analysis can provide useful hints and information regarding the best model approach to be used by assessing its degrees of significance and reliability. Few studies deal with uncertainty assessment in the integrated urban-drainage field. In order to fill this gap, there ha…

Antimicrobial susceptibility and quinolone resistance mechanism of Arcobacter butzleri isolates from sewage samples in Spain

2012

Risk factors for gastroenteritis associated with canal swimming in two cities in the Netherlands during the summer of 2015: A prospective study

2017

Urban canal swimming events are popular in the Netherlands. In 2015, two city canal swimming events took place, in Utrecht (Utrecht Singel Swim, USS) and in Amsterdam (Amsterdam City Swim, ACS). This prospective study characterizes the health risks associated with swimming in urban waters. Online questionnaires were sent to 160 (USS) and 2,692 (ACS) participants, with relatives of participants who did not swim completing the questionnaire as a control. Swimming water specimens and stool specimens of diarrheic participants in the ACS group were analysed. A total of 49% of USS and 51% of ACS swimmers returned their questionnaires. Nine percent of USS swimmers and 4% of non-swimmers reported g…

Radionuclides in wastewater treatment plants: monitoring of Sicilian plants.

2015

Three Sicilian wastewater treatment plants were monitored to assess the occurrence and the behaviour of radionuclides. Two sampling campaigns (screening and long-term) were carried out during which liquid and solid samples have been analysed. It was found that 131I mostly occurred in the samples analysed during the screening campaign (43% of the analysed samples contained 131I). High 131I specific activity was found in the mixed liquor, recycled sludge and dehydrated sludge samples. This finding was mainly due to the tendency of 131I to be associated with solid particles. During the long-term sampling campaign an influence of the sludge retention time (SRT) on the 131I behaviour was found. …

Regional differences in returns to education for entrepreneurs versus wage earners

2010

Many studies suggest that rates of return to schooling are lower for entrepreneurs than for employees, although the opposite has also been reported. This paper analyses the returns to education for entrepreneurs in urban and rural regions in Finland and compares these to the returns for wage earners. These areas show different rates of self-employment, higher rates being found in rural areas and lower rates in urban areas. The analysis is based on a rich, register-based dataset that includes a 7% random sample of all Finns. To avoid potential sources of bias, Mincer-type income equations are estimated using different estimation procedures. The results show regional variation in returns to e…

Evaluation of the fuel potential of sewage sludge mixtures with beech sawdust and lignite

2018

Sewage sludge (SS) from municipal wastewater treatment has drawn serious attention of scientists around the world in the attempt to find feasible disposal methods. Therefore, in this work, a solution for valorisation of SS as solid fuel is proposed based on an advanced compositional investigation of SS versus conventional solid fuels, namely, lignite (L) and beech sawdust (BS). A characterisation in terms of proximate analysis and ultimate analysis was performed for the studied materials, both to SS, L, and BS as single fuel and to bi-component mixture formulas of SS and L/BS, in variable proportions of 30:70, 50:50, and 70:30. SS:BS based blends had higher hydrogen (from 4.43 wt. % to 5.14…

A data analysis approach to evaluate the impact of the capacity utilization on the energy consumption of wastewater treatment plants

2019

Abstract The reduction of energy consumption in Waste Water Treatment Plants (WWTPs) is a challenge for the scientific community and for the public authorities. A source of excessive energy cost is the mismatching between operational and design inflow (i.e. capacity utilization): this issue is very relevant above all in areas with high demographic seasonality. Consequently, it is really important to have operational decision criteria to evaluate the impact of a low capacity utilization on energy consumption. In order to provide the scientific community and the plant managers with an adequate criterion, we propose a user-friendly methodology to identify critical conditions of capacity utiliz…