Search results for "WASTE"
showing 10 items of 2580 documents
A field methodology to study effects of UV radiation on fish larvae.
2003
There is a considerable lack of in situ specific information about the effects of UV-B radiation on limnic animals studied in the field. We exposed larval pike (Esox lucius L.) in two types of cuvettes (glass and quartz) placed at different depths (5 or 15 cm) to natural solar UV or to artificially enhanced UV-B (lamps on 3 h per day), simulating the scenarios for coming decades. Dose realism and comparability with earlier laboratory experiments was the main purpose, and therefore UV-B irradiances to the surface as well as underwater irradiances were directly measured. Result showed that UV-B dose rates in natural waters are low even though DOC concentration was low (4.8 mg/l) in our study …
Global sensitivity and uncertainty analysis of a microalgae model for wastewater treatment.
2022
The results of a global sensitivity and uncertainty analysis of a microalgae model applied to a Membrane Photobioreactor (MPBR) pilot plant were assessed. The main goals of this study were: (I) to identify the sensitivity factors of the model through the Morris screening method, i.e. the most influential factors; (II) to calibrate the influential factors online or offline; and (III) to assess the model's uncertainty. Four experimental periods were evaluated, which encompassed a wide range of environmental and operational conditions. Eleven influential factors (e.g. maximum specific growth rate, light intensity and maximum temperature) were identified in the model from a set of 34 kinetic pa…
Quantifying submarine groundwater discharge in the coastal zone via multiple methods
2006
Submarine groundwater discharge (SGD) is now recognized as an important pathway between land and sea. As such, this flow may contribute to the biogeochemical and other marine budgets of near-shore waters. These discharges typically display significant spatial and temporal variability making assessments difficult. Groundwater seepage is patchy, diffuse, temporally variable, and may involve multiple aquifers. Thus, the measurement of its magnitude and associated chemical fluxes is a challenging enterprise. A joint project of UNESCO and the International Atomic Energy Agency (IAEA) has examined several methods of SGD assessment and carried out a series of five intercomparison experiments in di…
Analysis of perfluoroalkyl substances in waters from Germany and Spain
2012
Water has been identified as one of the main routes of human exposure to perfluoroalkyl substances (PFASs). This work assessed the presence of 21 PFASs along the whole water cycle using a new fast and cost effective analytical method based on an online sample enrichment followed by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). The method was validated for different types of matrices (ultrapure water, tap water and treated wastewater). The quality parameters for the 21 selected compounds presented good limits of detection (LOD) and quantification (LOQ) ranging, in general, from 0.83-10 ng/L to 2.8-50 ng/L, respectively. The method was applied to assess the occurrence …
Evaluation of Biogas Production and Usage Potential
2016
Abstract The aim of the research is the development of theoretical and methodical bases for determining the feasibility of plant raw materials growing for its further bioconversion into energy resources and technological materials to maximize profit from business activities. Monograph, statistics, modelling and abstract logical methods have been used during the research. Directions of biogas usage have been examined. Biogas yields from different crops have been analyzed. It has been determined that high methane yields can be provided from root crops, grain crops, and several green forage plants. So, forage beet and maize can provide more than 5,500 m3 of biogas per hectare. Attention is pai…
Mineral Deposit Formation in Gas Engines During Combustion of Biogas from Landfills and Municipal WWTP
2020
Abstract The biogas produced in municipal wastewater-treatment plants (WWTP) should be cleaned before it can be used as a fuel in internal combustion engines. Efficient running of such engines is possible only subject to using high quality biogas and lubricating oil. Otherwise, biogas impurities in course of complex chemical reactions may form deposits on various engine parts as well as seriously contaminate the lubricating oil. In this paper, mineral deposits containing high concentration of bismuth, silicon, sulphur, calcium and zinc are studied. Silicon deposits demonstrating strong friction properties are formed during combustion of volatile silica compounds. As these deposits build up,…
Chlorinated cymenes in effluents of two Finnish pulp mills in 1990–1993
1995
Abstract Seven chlorocymenes (CYMS) and 2,3,6-trichloro-p-cymenene (236CYMD) were determined in effluents of biological purification plants of two Finnish pulp mills during the years 1990–1993. Both pulp mills changed their bleaching process and consequently, a steep decreasing trend in emitted amounts of the studied compounds was noticed.
Producing high-strength liquor from mesophilic batch acidification of chicken manure.
2015
This report describes the results from anaerobic batch acidification of chicken manure as a mono-substrate studied under mesophilic conditions. The manure was diluted with tap water to prevent methane formation during acidification and to improve mixing conditions by reducing fluid viscosity; no anaerobic digester sludge has been added as an inoculum. Highest acidification rates were measured at concentrations of 10 gVS L−1 and 20 gVS L−1; the pH value remained high (pH 6.9–7.9) throughout the test duration and unexpected fast methane formation was observed in every single batch. At substrate concentrations of 10 gVS L−1 there was a remarkable methane formation representing a value of 82% …
The closure of water circuits by internal thermophilic (55 and 70�C) anaerobic treatment in the thermomechanical pulping process
1997
The suitability of an internal thermophilic anaerobic treatment system for closing the water circuits in thermomechanical pulp (TMP) production was studied. The dissolution of wood organics in the water circuit was simulated by hot disintegration of TMP pulp, while the water system closure was simulated by repeated hot disintegration of TMP pulp with recirculated water. The upflow anaerobic sludge blanket (UASB) reactors were started at 55 and 70°C with mesophilic inoculum, and stable performances were established within 60 days at both temperatures. Closing the water circuits without internal treatment rapidly resulted in increased chemical oxygen demand (COD) in the recirculated water. In…
Pilot-scale comparison of thermophilic aerobic suspended carrier biofilm process and activated sludge process in pulp and paper mill effluent treatme…
2004
Thermophilic aerobic treatment of settled pulp and paper mill effluent was studied under mill premises with two comparative pilot processes; suspended carrier biofilm process (SCBP) and activated sludge process (ASP). Full-scale mesophilic activated sludge process was a reference treatment. During the runs (61 days) hydraulic retention times (HRTs) were kept 13 ± 5 h and 16 ± 6 h for SCBP and ASP, respectively. Corresponding volumetric loadings rates (VLR) were 2.7 ± 0.9 and 2.2 ± 1.0 kg CODfilt m-3d-1. Temperatures varied between 46 to 60°C in both processes. Mesophilic ASP was operated with HRT of 36 h, corresponding VLR of 0.7 kg CODfilt m-3d-1. Both SCBP and ASP achieved CODfilt (GF/A f…