bluuebunny/crossref_metadata_2025_split huggingface dataset:
Uncertainty in return period analysis of combined sewer overflow effects using embedded Monte Carlo simulations
Authors: Grum Morten , Aalderink R. Hans 
Published: May 2018

The return periods of detrimental effects are often used as design criteria in urban storm water management. Considerable uncertainty is associated with the models used. This is either ignored or pooled with the inherent event to event variation such as rainfall depth. It is here argued that uncertainty and inherent event to event variation should be treated separately, in providing engineers and managers with the distributions of return periods. It is then possible to base management decisions on knowledge of both the expected return periods and their corresponding confidence limits. It is further argued that the traditional pooling of inherent variation and uncertainty leads to meaningless return period curves with little engineering value.
All quantities which are described by a probability distribution are placed in either of the two layers: an inner layer consisting of quantities varying from event to event and an outer layer consisting of uncertain but constant quantities. For each set of random realisation of the values in the outer uncertainty layer a full set of Monte Carlo simulations for the inner inherent variations layer is performed resulting in a return period curve. The many samplings in the outer layer results in a band of return period curves representing the distribution of return periods for which confidence limits may be calculated. The general methodology is here described as Embedded Error Propagation and its current implementation as Embedded Monte Carlo Simulations.
The approach is demonstrated in an integrated setting involving models for rainfall characteristics, combined sewer overflow (CSO) loads and impacts on the surface water dissolved oxygen (DO). CSO loads are modelled using event lumped non-linear regression models with rainfall as input and with overflow volume, duration and relevant event mean concentrations as output. Oxygen depletion in the surface water is described using a dynamic model including oxidation of dissolved chemical oxygen demand (COD) and nitrification. Conversion models had to be developed to integrate the output variables of the CSO model with the input variables of the surface water model. The parameters of all the models were estimated from observed data on rainfall, CSO load and surface water impacts. The background conditions of the surface water were modified creating a hypothetical, but more general and relevant case to present the methodology. Focus is in this paper on chemical effects of CSO on a surface water. The proposed distinction between event to event variation and uncertainty and the associated methodology are equally valid to the return period analysis of flooding.
Optimizing Biological Nutrient Removal in anoxic zones
Authors: Stevens Gerald M. , Barnard James L. , Rabinowitz Barry 
Published: May 2018

During the initial years of the development of Biological Nutrient Removal (BNR) technology, it was assumed that the bacterial species responsible of the removal of phosphorus (BioP organisms) could not use nitrates as a final electron acceptor and could thus not denitrify. The carbon taken up in the form of Volatile Fatty Acids (VFA) in the anaerobic zone was thus deemed to be unavailable for denitrification in the anoxic zone. This was reinforced through experiments in which BioP organisms cultured in the high-rate Phoredox system in which no nitrification took place, did not denitrify when nitrates were added. Many researchers (e.g. Dold and Barker) have since shown that in BNR systems such as the 3-Stage Bardempho system, where nitrates are recycled to the anoxic zone which follows the anaerobic zone, a high degree of phosphorus uptake through denitrification does occur. In addition, the partial diversion of primary effluent directly to the anoxic zone has significantly improved phosphorus uptake under anoxic conditions.
Full-scale operations at the Westbank, British Columbia, plant showed a substantial uptake of phosphorus in the anoxic zone in the absence of oxygen. The Westbank configuration includes side stream primary sludge fermentation, VFA rich fermenter supernatant addition directly to the anaerobic zone and diversion of a portion of primary effluent to the anoxic zone. This configuration stimulates P-uptake under anoxic conditions, demonstrates the efficient use of carbon and is instrumental in achieving an annual average effluent Total-P concentration of less than 0.17 mg/l.
The phenomenon of denitrification by BioP organisms was included in the Biowin Model developed by Dold (Biowin Manual). This paper describes experiments and full-scale plant observations to establish the role of BioP organisms in the removal of nitrates in the anoxic zone of a plant which also receives a portion of the primary effluent and verification of the Biowin model.
Appropriate Technologies for Effective Management of Industrial and Domestic Waste Waters: The Decentralised Approach
Authors: van Lier Jules B. , Lettinga Gatze 
Published: May 2018

The increasing scarcity of clean water sets the need for appropriate management of available water resources. Particularly regions suffering from a lack of water urgently need integrated environmental protection and resource conservation (EP&RC) technologies in order to enable effective management of the available water resources. EP&RC-concepts focus on a minimum of consumptive use of energy, chemicals, and water and a maximum of reuse of treated wastewater and of residues produced from the pollutants present in the wastewater. Consequently, by implementing these concepts, instead of a social threat, waste(water)s like sewage and industrial effluents become an important resource for water, fertilisers, soil conditioners and to some extent also energy. In addition, a bridge is made between environmental protection and agriculture practice, stimulating (urban) agriculture in the neighbourhood of large cities.
Anaerobic treatment is considered as the core technology for mineralising organic compounds in waste(water) streams. Additional technologies are required to comply with the reuse criteria. Some examples of possible EP&RC concepts, using the anaerobic treatment technology for the reclamation of domestic sewage are discussed.
Modelling denitrification in a moving bed of porous carriers from a low-loaded wastewater treatment plant
Authors: Maurer M. , Fux C. , Lange D. , Siegrist H. 
Published: May 2018

A model was developed to describe hydrolysis in a moving bed with polyurethane foam carriers under anoxic conditions. It is formulated as a two-box model and structured into bulk and carrier compartments linked by mass transfer processes for solutes and particles. The biological processes consist of the anoxic growth and decay of heterotrophic organisms and hydrolysis of the slowly biodegradable substrate. Kinetic and stoichiometric parameters are taken from Activated Sludge Model No. 2 (Henze et al., 1995). Parameter estimations based on 24 batch experiments resulted in anoxic hydrolysis rates of 3.9 d−1 (at 20°C) and 2.6 d−1 (at 10°C).
The mass transfer coefficient for solutes was determined from the mixing of an inert tracer to be 0.3 m d−1. Measurements of the enzymatic activity of α-, β-glucosidase and esterases confirmed that 90% of the activity involves the carriers. In conjunction with the finding that the absorption capacity of the carriers for slowly biodegradable substrate is high, it can be concluded that the hydrolysis takes place principally within the carriers.
Activated sludge system modelling and simulations for improving the effluent water quality
Authors: Cheng Chia-Yau , Ribarova Irina 
Published: May 2018

This paper describes the results from a study carried out to investigate the feasibility of upgrading Parada wastewater treatment plant (WWTP) for biological nitrogen removal. The biological treatment of Parada WWTP is a conventional activated sludge process. Since 1992 only one of the three available aeration tanks has been used.
Activated Sludge Model No.1 was used as a base for modelling of the activated sludge system. To accomplish all the calculations, AQUASIM software was applied. The model was calibrated and verified with data from Parada WWTP operation. Very good correlations between measured data and simulation results were achieved using stoichiometric and kinetic parameter values proposed by the authors of IAWQ Model No. 1. However, characterisation of the actual wastewater was necessary.
Computer simulations with a verified and extended model were done to study whether the capacity of the treatment plant is enough for biological nitrogen removal. Very high effluent quality can be achieved if the first tank volume is used for denitrification, the second and third tank volumes are used for BOD removal and nitrification, the recirculating effluent flow ratio is 1.5 and the sludge age is 15 days.
An Alternative Use of Biogas Applied at the Water Denitrification
Authors: Houbron Eric , Torrijos Michel , Capdeville Bernard 
Published: May 2018

The urban wastewater treatment plants of the 21st century will have to consider the removal of the carbon, nitrogen and phosphorus. On one hand, the usual exogenous carbon source for tertiary treatment are generally supplied as methanol, ethanol, acetic acid, etc. On the other hand, the anaerobic wastewater treatment plant produces a biogas which contains up to 90 % of methane and which could be used as a cheap carbon source for denitrification.
The first step of this work conducted in batch culture with or without copper, has shown that a consortium of methanotrophic and denitrifying bacteria are involved in this process. The methanotrophic bacteria oxidises methane under aerobic conditions via a specific enzyme (Methane Mono Oxygenase) and produces a soluble organic carbon in the liquid phase available for the denitrification.
During the batch culture, when dissolved oxygen concentration decreases below 1 mg/l, a maximum denitrification rate of 3.3 mg N-NO3/l.h was obtained with 80 μg/l of copper in the medium. The consumption rate of methane was 3.5 mmol CH4/l.h. The molar ratio of the oxygen/methane consumed was 1.27, and the mass ratio of C-CH4 consumed to N-NO3 eliminated was 10.9.
During chemostat culture, denitrification on synthetic and real nitrifying water was tested. The stability of the consortium has been verified under different culture conditions. The variation of the dilution rate showed that the maximum one was 0.16 h−1. The specific denitrification rate obtained with synthetic and real water were respectively 6.1 and 9.47 mg N-NO3/TSS.h, with a C/N mass ratio of 3.6 and 4.6. In chemostat, culture the efficiency of the methane oxidation and the denitrification was improved.
Influence of Humic Substance Alteration during Soil Passage on their Treatment Behaviour
Authors: Gerlach M. , Gimbel R. 
Published: May 2018

Humic substances are not major objectives of water treatment in drinking water supply. But, as they often influence the treatment efficiency or participate in treatment reactions, their behaviour in the treatment process can significantly determine the process design. A very effective pretreatment step can be achieved by soil passage (e. g. bank filtration or slow sand filtration) which is usually involved in German surface water treatment processes. In this study transport phenomena of humic matter during underground passage are investigated with special attention to the alteration of their treatment behavior.
In a fundamental work the deposition of humic substances was studied in a model system. Transport phenomena could mathematically be described by a filtration theory of colloidal transport. From the results of these calculations the collision efficiencies of humic substances on clean and coated surfaces can be derived. The humic substance deposition on subsurfaces is accompanied by a classification based on molecular weight. An additional alteration of dissolved humic matter due to microbiological degradation and partial resolvation of deposited humic matter was observed by passage of river water through columns containing actual soil. The alteration of dissolved organic matter during soil passage is finally characterized by its adsorption and chlorination precursor behaviour. All results confirm that bank filtration is an effective pretreatment step particulary due to the decrease in connection with improvement in treatability of humic matter.
Optimal Combination of Flocculating Filtration and Ultra Filtration for Advanced Effluent Treatment in the Netherlands
Authors: de Koning J. , van Nieuwenhuijzen A. F. 
Published: May 2018

With changing policies to solve local environmental and dehydration problems and with increasing interest in differentiation of water qualities by industrial and domestic users, a growing need exists to improve the effluent quality of wastewater treatment plants (wwtp) in the Netherlands. The change of policy to retain water in its original environment as much as possible leads to an increasing interest in discharging wwtp effluent into polders and local water courses instead of large surface waters. Besides, a new element is the interest in the production of household and industry water by the Dutch drinking water companies.
At several Dutch wwtp's research on (the combination of) fluocculating filtration and ultra filtration is done to develop the possibilities of (re)using effluent in the Netherlands. The results of the research have shown that flocculating filtration and/or ultra filtration are technically and economically applicable for the production of household and industry water.
Membrane Treatment of Secondary Textile Effluents for Direct Reuse
Authors: Rozzi A. , Antonelli M. , Arcari M. 
Published: May 2018

Post-treatment of secondary textile wastewater was tested at pilot scale on membrane modules (microfiltration MF, nanofiltration NF and reverse osmosis RO) for the direct reuse of polished effluent within the dyeing processes. The main polluting parameters monitored in the post-treatment were: organic compounds (COD), colour, surfactants and salinity (as conductivity).
The first treatment scheme was made of ceramic MF followed by NF. Aluminium polychloride was added at high concentrations (of the order of 70 mg Al/L) to avoid MF membrane fouling. The quality of the final permeate, produced by NF fed on the MF permeate, was acceptable for water reuse.
Clariflocculation (CF) plus multimedia filtration (MMF) followed by low-pressure RO was also tested. This process performed quite well: the RO module (p = 4 bar) ran for relatively long cycles (up to 80 hours) with 5% reduction of the permeate flow rate at a 10 L m−2 h−1 fluxes.
A techno-economical analysis on the experimental data indicate that a high quality effluent (COD &lt; 10 mg/l; conductivity &lt; 40 μS/cm; negligible residual colour), to be recycled in the textile dyeing industry, may be produced at affordable costs (less than 0.25 ECU) from secondary textile wastewater.
Comparative study of wastewater purification efficiencies of two emergent helophytes: Typha latifolia and juncus subulatus under arid climate
Authors: Abissy M. , Mandi L. 
Published: May 2018

The aim of the present study is to assess wastewater purification efficiency of two higher aquatic plant, Typha latifolia and Juncus subulatus in an arid climate.
The experiment was conducted from August 1994 to March 1996. The plots (capacity: 115 liters, diameter: 57 cm) were filled to 5 cm depth with gravel and 30 cm with soil (texture: 30% clay, 34% silt and 36% sand) and planted with young shoots of Typha and Juncus. The plots without plant were used as controls. The plots were weekly and exclusively irrigated by urban raw wastewater (25 liters). The influent was percolating through the substratum.
Results revealed significant performances for reduction of organic load in all systems. Indeed, COD and TSS removal efficiencies were respectively 91% and 73% for Typha latifolia, 92% and 76% for Juncus subulatus, 83% and 73% for an unplanted system. Depletion of nutrients during the experimental period was low and even negative: 32% TP (total phosphorus) and 31% NH4 (ammoniacal nitrogen) in Typha system, 27% TP and 17% NH4 in Juncus system, −10% TP and −22% NH4 in unplanted system.
In addition, the presence of these helophytes maintained sufficient porosity in order to allow water percolation treatment. The unplanted system clogged in winter.
Treating high-strength nitrate wastewater by three biological processes
Authors: Chen Shing-Der , Chen Chiu-Yang , Wang Yu-Feng 
Published: May 2018

Three different types of bioreactors including an activated sludge reactor (ASR), a biologically mediated activated carbon fluidized bed reactor (BAFBR) and an upflow immobilized cell reactor (UICR) were studied. The results suggest that the carbon-nitrogen equivalent (CNE) ratio (in terms of CODN) when using ASR to treat the wastewater will decrease as the sludge age increases while it will increase slightly as the influent concentration increases. The CNE ratios for BAFBR and UICR are 3.67 and 3.61 respectively. For the test between the two different growth types, the CNE ratio of suspended growth will be lower than the one of attached growth.
The alkalinity-nitrogen equivalent (ANE) ratio (in term of Alk/N) for ASR is 3.78, for BAFBR it is 3.54, and for UICR it is 3.63. These ANE ratios are comparable with the theoretical value of 3.57. Under different operating conditions, slight changes of microorganisms are detected in Scanning Electron Microscope observation, but the dominant species, bacillus group, showed superior growth in all cases. Tests with the immobilized cells, biofilms will grow on the surface of them at the end of operation and the subsequent biochemical reactions will concentrate on the outer layer of biofilms.
Biomarker Responses by Crucian Carp (Carassius Carassius) Living in a Pond of Secondary Treated Pulp Mill Effluent
Authors: Kukkonen J. V. K. , Punta E. , Koponen P. , Paranko J. , Leppänen H. , Holopainen I. J. , Hyvärinen H. 
Published: May 2018

Biochemical and histological biomarkers by the adult crucian carp (Carassius carassius (L.)) living in a biologically treated pulp mill effluent were studied. Enocell pulp mill in Uimaharju, Finland, discharges its effluents through a waste water pond to the River Pielisjoki. This pond harbours an introduced crucian carp population that apparently reproduces on site. The objective of the present study was to measure possible hormonal effects of treated pulp mill effluent on crucian carps living in a wastewater pond. Adult fish were collected for analysis by traps. A reference population was sampled from a small natural pond. Blood and bile samples were taken for analyses of hemoglobin, hematocrit, testosterone, triiodothyronine (T3), thyroxine (T4), vitellogenin, organic chlorine compounds, resin acids and neutral wood-based compounds. In addition, a histological analysis of male gonads was made.
The exposed fish had higher concentration of organic chlorine compounds, resin acids and β-sitosterol in bile compared to the reference fish. The same compounds could also be found in sediment of the wastewater pond. The exposed male fish had higher liver somatic index (LSI), lower gonad somatic index (GSI), lower haemoglobin and haemocrit, but higher T3 than in the reference fish. In addition, in an average, increased plasma testosterone concentration and decreased thyroxin (T4) levels were found in the exposed male fish. No vitellogenin production was found in the exposed male fish and some females showed decreased vitellogenin levels. The histological structure of the gonads in the exposed males was normal. The results suggest more anti-estrogenic than estrogenic effects of pulp mill effluents on the crucian carp.
Composting of Forest Industry Wastewater Sludges for Agricultural Use
Authors: Rantala P.-R. , Vaajasaari K. , Juvonen R. , Schultz E. , Joutti A. , Mäkelä-Kurtto R. 
Published: May 2018

The feasibility of composting of pulp and paper industry sludges was studied. The aim was to study the progress of the composting process and the toxicity and applicability of the sludges in agriculture. Five different sludges were used: two biosludges and three biosludge and primary sludge mixtures. The sludges were composted in seven piles, two smaller of them founded with leachates collection systems. The piles were monitored throughout the composting period by physical measurements, chemical analyses and toxicity tests. Also the lignin concentrations were measured from the sludges and from the soil as well as the amount of mycelium.
The results showed that all sludges were easily composted and they will be suitable for the use as soil improvement in agricultural plant production. Toxicity of the sludges decreased during composting and all the sludges were proved to be non-toxic at the end of the composting. Heavy metal concentrations were low in all sludges and leachates. The leachates were also non-toxic and the concentrations of nutrients were low.
Microbially mediated attenuation potential of landfill bioreactor systems
Authors: Pohland F.G. , Kim J.C. 
Published: May 2018

The origin and fate of landfill leachate and gas constituents generated during the sequential phases of solid waste transformation and stabilization are emphasized within the perspective of the in situ processes of microbially mediated attenuation. The fundamental biochemical and physicochemical reaction mechanisms are presented in terms of their spatial and temporal dimensions and their significance for transformation of both nonhazardous and hazardous waste constituents. Supporting information from laboratory, pilot-scale and full-scale applications is used as a basis for interpretive analysis and for providing operational guidance and promoting future developments.
The diversity, domains, and functional interdependence of the acidogenic, methanogenic, sulfate and nitrate reducing, nitrifying and denitrifying, and methanotrophic consortia are addressed in order to reveal opportunities for landfill process modifications and associated operational optimization. Controlled attenuation, linked with operational and regulatory realities, are used to suggest innovative landfill configurations involving prospective compartmentalization and integrated waste loading, dedicated treatment zones for in situ transformation of waste and leachate constituents with associated gas capture, control and utilization. Monitoring requirements are emphasized to provide guidance and feedback for operational control and environmental compliance. Finally, technology needs for establishing a more unified approach to the development and management of bioreactor landfills are presented.