bluuebunny/crossref_metadata_2025_split huggingface dataset:
Survey of filamentous populations in nutrient removal plants in four European countries
Authors: Eikelboom Dick H. , Andreadakis Andreas , Andreasen Kjaer 
Published: May 2018

A joint EU research project aimed at solving activated sludge bulking in nutrient removal plants was initiated in 1993. The project started with a survey of the size and composition of the filamentous population in nutrient removal plants in Denmark, Germany, Greece and the Netherlands.
The results show that biological nutrient removal process conditions indeed favour filamentous microorganisms in their competition with floc forming organisms. An increase in the size of the filamentous population resulted in a deterioration of the settling properties of the biomass, except for plants with Bio-P removal conditions. It is assumed that in the latter case the dense clusters of Bio-P bacteria increase the weight of the flocs, and compensate for the effect of the larger number of filaments.
Although exceptions frequently occur, the following sequence in decreasing filamentous organism population size was observed for the process conditions indicated:
- completely mixed + simultaneous denitrification;
- completely mixed + intermittent aeration/denitrification;
- alternating anoxic/oxic process conditions, with an anaerobic tank for biological phosphate removal (Bio-Denipho);
- alternating anoxic/oxic process conditions (Bio-Denitro);
- predenitrification
The surveys provided little information about the effect of nutrient removal in plants with plug flow aeration basins. Simultaneous precipitation with aluminium salts nearly always resulted in a low number of filaments and a good settling sludge.
The size of the filamentous organism population showed a seasonal pattern with a maximum in winter/early spring and a minimum during summer (in Greece: during autumn). This seasonal variation is primarily caused by the effect of the season on the population sizes of M. parvicella, N. limicola and Type 0092.
M. parvicella is by far the most important filamentous species in nutrient removal plants. In Denmark only, Type 0041 also frequently dominates the filamentous population, but seldom causes severe bulking. Considering their frequency of occurrence, approx. 10 other filamentous micro-organisms are of minor importance. Growth of some of these species, viz. those which use soluble substrate, can be prevented by the introduction of Bio-P process conditions.
M. parvicella and Type 0041 (and probably also Actinomycetes and the Types 1851 and 0092) seem to compete for the same substrates i.e. the influent particulate fraction. Most of the differences in composition of the filamentous microorganism population can be explained by whether or not premixing of influent and recycled sludge is used. In general, premixing for a short period of time followed by anoxic conditions favours Type 0041. M. parvicella seems to proliferate if the particulate fraction is first hydrolysed or if it enters the plant via an oxic zone. It is concluded that bulking in nutrient removal plants is mainly caused by filamentous species requiring the particulate fraction for their growth.
Physico chemical characteristics and multivariate analysis of contaminated harbour sediments
Authors: Ausili Antonella , Mecozzi Mauro , Gabellini Massimo , Ciuffa Giuseppina , Mellara Francesco 
Published: May 2018

Dredging is a very important procedure within harbour management.
Italian legislation regulates dredging activity requiring high number of sampling stations and physico chemical and biological parameters but the criteria for their interpretation are not reported adequately. The comprehension of the information included in the data is a very critical step of every dredging activity of harbour sediments and the traditional examination of these large database (searching of average values of pollutants or simple correlations among pollutants) does not make easy their interpretation. So the included information can result hidden than clarified.
With the aim to perform a complete characterization of the examined area we applied Principal Components Analysis (PCA) and Cluster Analysis (CA) to the examination of a complex data matrix consisting of the physico chemical characterization (sediment texture, heavy metals, organic pollutants) of the industrial canal sediments in Livorno harbour. The multivariate methods allowed to study the general distribution of pollutants in the Livorno canal, clarifying also the significant parameters for the characterization of the system.
The use of flux-corer experiments in the determination of heavy metal re-distribution in and of potential leaching from the sediments
Authors: Van Ryssen R. , Alam M. , Goeyens L. , Baeyens W. 
Published: May 2018

Metal dynamics between sediments, interstitial water and overlying water are particularly complex. The movement of metals, their availability, and possible toxicity are influenced by various chemical and physical reactions and factors such as oxygen/redox gradients, pH, grain size, etc. To study the impact of oxygen on the release from and the re-distribution of Cd, Pb, Zn and Cu in sediments, flux-corer experiments have been optimised and performed.
The flux experiment was carried out using 3 identical sediment cores. The first (control) sediment core was completely characterised before, the two other cores after the experiment. Pore water extractions and sequential extractions were performed on 2 cm depth intervals throughout the 20 cm long sediment cores.
In the flux experiment, the sediment cores were exposed to a small volume of overlying water, which was continuously renewed. The change of trace metal mobility was assessed by following concentration-changes in the outflow. It has been found by the use of the flux-corer experiment, that the Cd, Pb, Zn and Cu concentrations in the outflow are at least 3-6 times higher during oxic conditions. Flux-corer experiments can be useful tools to facilitate the study of the change of heavy metal mobility and distribution in the sediment induced by the change in surface water policy.
Effluent nutrient management and resource recovery in intensive rural industries for the protection of natural waters
Authors: Biswas T. K. , Higginson F. R. , Shannon I. 
Published: May 2018

Intensive rural industry is developing rapidly in parts of inland Australia. The usually nutrient and salt rich effluent from these sources has traditionally been disposed to both land and water bodies. Since direct water discharge is no longer permitted, a challenge now exists when applying effluent to land especially where the rate of application exceeds crop requirements. Effluent of high volume and concentration of nutrients and/or salts can easily contaminate land and water resources. Predicting the optimum rate of land application of effluent is complicated by the physical, chemical and biological properties of soils.
This paper addresses the characteristics of effluents from various intensive rural industries and their potential environmental impacts when irrigated to agricultural land in New South Wales, Australia. To assess the environmental sustainability of effluent reuse in land application, a mathematical model (ERIM) has been developed based on a monthly water balance. ERIM includes historical rainfall and evaporation; the amount of nitrogen and phosphorus introduced; their yearly removal by plants to be grown; amount of applied organic matter; and water holding capacity of soil.
The requirement of metal cations for enhanced biological phosphorus removal by activated sludge
Authors: Pattarkine Vikram M. , Randall Clifford W. 
Published: May 2018

The objectives of the study described in this paper were to study the requirements of potassium, magnesium, and calcium for enhanced biological phosphorus removal (EBPR) and to determine whether either potassium or magnesium could support EBPR on its own.
Batch experiments indicated that phosphorus uptake by the sludge was affected by the availability of potassium, magnesium, and calcium. Both potassium and magnesium were simultaneously required and neither was adequate by itself for EBPR. Calcium did not appear to be required for EBPR, and did not seem to be involved in biologically mediated chemical precipitation.
Pollution retention capabilities of roadside soils
Authors: Dierkes C. , Geiger W. F. 
Published: May 2018

Runoff from highways contains significant loads of heavy metals and hydrocarbons. According to German regulations, it should be infiltrated over embankments to support groundwater-recharge. To investigate the decontaminating effect of greened embankments, soil-monoliths from highways with high traffic densities were taken. Soils were analyzed to characterize the contamination in relation to distance and depth for lead, zinc, copper, cadmium, PAH and MOTH. Lysimeters were charged in the field and laboratory with highway runoff to study the effluents under defined conditions.
Concentrations of pollutants in roadside soils depend on the age of embankments and traffic density. Highest concentrations were found in the upper 5 cm of the soil and within a distance of up to two metres from the street. Concentrations of most pollutants decreased rapidly with depth and distance. Lead and cadmium could not be detected in lysimeter effluent. Zinc and copper were found in concentrations that did not exceed drinking water quality limits.
Constructed Wetlands: A Chance to Solve Wastewater Problems in Developing Countries
Authors: Haberl R. 
Published: May 2018

There is a great lack of proper wastewater treatment in developing countries. With respect to the environment this situation should be changed as fast as possible. Due to the financial situation and to the more stringent standards, wastewater sewerage and treatment are much more developed in industrialized countries. Consequently there is an enormous pool of experience and knowledge in these countries with a lot of different systems based on scientific and practical work.
One of the most promising technologies for application in developing countries seems to be constructed wetlands (CW), due to their characteristic properties like utilization of natural processes, simple construction, simple operation and maintenance (O/M), process stability, cost effectiveness, etc.
Our Institute has been dealing a lot with CW and now feels obliged to transfer its know-how in this field to developing countries to help them in solving their problems. At the moment we are cooperating with the following countries: China, Kenya, Mexico, Nepal, Nicaragua, Tanzania and Uganda. Different ways are being followed to realize this together with several organisations and partners.
The paper will deal with these cooperative arrangements in detail, demonstrating different projects, describing the procedures in the projects, discussing experiences and last but not least giving recommendations for future optimum ways of proceeding.
Capacity of Constructed Wetlands to Remove Parasite Eggs from Wastewaters in Egypt
Authors: Stott R. , Jenkins T. , Bahgat M. , Shalaby I. 
Published: May 2018

The use of Gravel Bed Hydroponic (GBH) constructed wetlands for wastewater treatment and reuse in semi-arid climates has been evaluated in Egypt with respect to the removal of parasite eggs from domestic wastewaters.
Influent and effluent from established 100m GBH reed beds receiving partially treated wastewater, were analysed to establish daily parasite loading rates and removal performance of the system under normal operating conditions (201/min; intermittent 12h on/off flow regime.) The system was then challenged with high numbers of parasite eggs (Ascaris sp., Hymenolepis sp. and Toxocara sp.) equivalent to an influent of 100-500 eggs/1 and a daily loading rate of 1.0-7.2 × 106, representing up to a 110-fold increase over typical mean daily loading rates. Wastewater samples were collected from the inlet, at varying distances along the 100m bed profile, and the outlet. Sampling was also carried out at varying time intervals during the flow regime to determine the spatial and temporal removal of eggs along the bed.
In 100m long planted beds, there was significant removal of all selected parasite eggs with the majority being removed within the first 25m. No eggs were detected in the final effluent. These studies demonstrate that GBH wetlands have a capacity for efficient removal of parasite eggs and thus provide a reliable, low cost technology for treating effluent compliant with health related objectives for the treatment of wastewater intended for agricultural reuse.
Wastewater Treatment by Tropical Plants in Vertical-flow Constructed Wetlands
Authors: Kantawanichkul S. , Pilaila S. , Tanapiyawanich W. , Tikampornpittaya W. , Kamkrua S. 
Published: May 2018

A subsurface vertical-flow laboratory scale wetland system was designed to investigate the wastewater treatment efficiency by Vetiveria zizanioides Nash, a common grass in Thailand. Diluted pig farm wastewater was fed intermittently. The removal efficiencies in terms of organic carbon, nitrogen and suspended solids were satisfactory under hydraulic and organic loading rates of 36 mm/d and 55 kgCOD/ha.d, respectively.
A comparison of the performance of the systems with Vetiveria zizanioides Nash and Cyperus flabelliformis Rottb. to treat domestic wastewater was made. It was found that both plants are suitable for wastewater treatment by vertical-flow constructed wetlands in tropical areas under hydraulic and organic loading rates within 121 mm/d and 198 kgCOD/ha.d, respectively.
Design and Hydraulic Performance of a Constructed Wetland Treating Oil Refinery Wastewater
Authors: Simi Anne L. , Mitchell Cynthia A. 
Published: May 2018

This paper considers the hydraulics of a wetland constructed by BP Oil for polishing wastewater from their oil refinery at Bulwer Island, Australia. As this open water surface flow (SF) wetland has a novel design to enhance mixing, a tracer study was performed to analyse the hydraulic flow distribution through the wetland. It is a baseline study, following construction, prior to planting. As introduction to the study, details of the wetland design are provided, together with design justification.
The volume of the wetland active zone is estimated as 70% of the total wetland capacity, which compares very favourably with the active volume expected in flat-bottomed ponds. The large amount of dispersion observed along the length of the wetland bed approaches that of a well-mixed system, supporting the claim that this novel bed structure enhances mixing. We expect to at least retain, and possibly improve the degree of mixing by alternating planted shallow zones with unplanted deep zones.
The first stage of experimental work at this wetland involves creating a baseline of hydraulic data on which to build a mass balance model of the wetlands performance. Tracer studies will be repeated on the planted, mature wetland to determine the changes to flow, which might occur in the operating system. Together with wetland performance results, these studies will underpin investigations into the pollutant removal mechanisms at BP Oil's Bulwer Island wetland.
Optimisation of the Hamburg wastewater treatment plants by dynamic simulation
Authors: Ladiges Gösta , Günner Christian , Otterpohl Ralf 
Published: May 2018

At present the combined wastewater treatment plants Köhlbrandhöft/Dradenau serve approx. 1.85m PE for the treatment of Hamburg wastewater. It is planned to add a further 250,000 PE and therefore it is necessary to carry out optimisation measures. With the help of an extensive project for dynamic simulation, the necessary comparative tests were carried out.
Various variants for the optimisation were tested and compared on the basis of 14-day and annual hydrographs. The results show clear differences in the performance of the variants. The dynamic simulation was able to provide very useful results on the basis of which decisions have been made on the most suitable measures to be taken in practice.
During work on the project the creation of a project team consisting of representatives from the works (planning and operational staff) and the simulation expert, who cooperated intensively in working on the ideas and concepts, proved invaluable. It meant that wide-ranging possibilities for optimisation were tried out and plausible results achieved.
Experiments on membrane filtration of effluent at wastewater treatment plants in the Netherlands
Authors: van der Graaf J. H. J. M. , Kramer J. F. , Pluim J. , de Koning J. , Weijs M. 
Published: May 2018

In the Netherlands interest in advanced treatment is increasing now that almost all wastewater treatment plants apply full biological treatment and nutrient removal. Membrane filtration of WWTP-effluent appears to be a very promising method to remove suspended solids and, in addition, bacteria and viruses. Experiments with a pilot unit consisting of a dual media prefilter and a membrane filter, containing capillary membranes with a pore size of 0.01 μm (ultrafiltration) and working in a semi dead-end mode, gave rather promising results. A flux of 90 l/m2.h was achieved after optimizing the cleaning procedures (TMP 0.6 bar, recovery &gt; 90%). Experiments with microfiltration (transverse flow module) based on the cross-flow principle were successful only at high cross flow velocities (flux 100 l/m2.h, TMP 0.5 bar, recovery 80%).
The ultrafiltrate showed an excellent quality with the absence of suspended solids and bacteria. Finally, low costs for energy (NLG 0.02/m3 (1 NLG = 0.5 US$)) and chemicals (NLG 0.01/m3) were calculated. Further optimization will facilitate the applicability of membrane filtration in the near future.
Assessment of alternative wastewater treatment approaches in guangzhou, China
Authors: Tao Y. X. , Hills P. 
Published: May 2018

The city of Guangzhou, in Guangdong Province, China, faces major problems in the development, implementation and application of a comprehensive water pollution control strategy. Since the 1980s, discharges of industrial wastewater and domestic sewage have increased dramatically, resulting in a continuing deterioration in the quality of urban water bodies. The Pearl River, which passes through the city, is now seriously polluted and water quality in many sections fails to attain even the lowest national surface water quality standards. The 19 urban creeks in the city are also badly polluted, and Guangzhou is facing a water shortage due to pollution of its supply sources.
This paper overviews the water pollution problem of Guangzhou. Existing approaches to wastewater treatment are evaluated using an Analytic Hierarchy Process (AHP) and a form of cost-effectiveness analysis. Problems associated with different approaches are explored. Options to improve the effectiveness of wastewater treatment are proposed. The paper seeks to demonstrate that in Guangzhou, the most effective approach to wastewater treatment involves the use of small and medium-scale treatment facilities. This is in contrast to the situation in many other parts of the world where greater emphasis has been placed on the development of large-scale facilities for wastewater collection, transport and treatment.
Bench-Scale Evaluation of Adsorptive Processes for Taste and Odors Control Using Rapid Small-Scale Column Tests and Flavor Profile Analysis
Authors: Crozes G. , Hagstrom J. , Suffet I. H. , Young C. 
Published: May 2018

The City of Appleton, Wisconsin operates an 800 l/s Drinking Water Treatment Plant (WTP). Lake Winnebago serves as the source water which experiences algae blooms that are typically accompanied by severe taste and odor (T&O) episodes. Historically, raw water quality in the summer months prevents the full capacity from being achieved despite the use of potassium permanganate, powdered activated carbon (PAC) and granular activated carbon (GAC) filters. Thus, the City proceeded with a study of various treatment processes to mitigate the T&O problems experienced during the summer months. The relatively short duration of T&O episodes and extensive experimental plan necessitated a bench-scale testing for rapid evaluation of various oxidation and adsorptive processes.
This paper presents a review of the effect of carbon type, dosage, contact time, and application point on the performance of PAC in controlling odors. In addition, the effect of GAC type and empty bed contact time (EBCT) on removal of T&O compounds were evaluated using a rapid small scale column test (RSSCT).
Development and Evaluation of a Partitioned Upflow Anaerobic Sludge Blanket (UASB) Reactor for the Treatment of Domestic Sewage from Small Villages
Authors: Chernicharo Carlos Augusto L. , dos Reis Cardoso Marcílio 
Published: May 2018

This paper presents the development and field evaluation of a partitioned UASB reactor, conceived for the treatment of domestic sewage from small villages and areas with large variation of the daily flowrate. In such situations, conventional single compartment UASB reactors are submitted to very extreme hydraulic conditions, that can disturb the behaviour of the treatment system. In the partitioned reactor, which is constituted of three digestion compartments, three gas separation devices and a single settler compartment, an adequate distribution of the variable incoming wastewater into one, two or three digestion chambers, allows the establishment of more stable up flow velocities and less occurrence of dead zones. As a result, a better contact between substrate and biomass can be achieved and an improved performance of the system can be expected.
The partitioned UASB reactor was evaluated during a period of 16 months of continuous operation. The system presented a vary good performance during most of the operational period, showing very high efficiencies when the reactor was operated at a HRT of 7.5 hours. In this phase, the unit presented COD removal efficiencies around 80% and an average SS concentration in the final effluent of 32 mgSS/L. The research is still going on, focussing on the evaluation of the system under higher hydraulic loads and on the assessment of sludge activity and dehydration potential.
Due to the operational simplicity and low cost of the system, it is believed that this type of reactor can become a very attractive alternative for domestic sewage treatment in small villages, particularly in Brazil where the number of rural areas with wastewater treatment is negligible.
Probabilistic modelling of sewer system overflow emissions
Authors: Willems P. , Berlamont J. 
Published: May 2018

The main advantages of the probabilistic modelling of urban drainage systems are the possibility of quantification and efficient reduction of the risk of ‘wrong’ management decisions or engineering designs, as well as the less biased mathematical modelling. Such probabilistic modelling achieves quantification of the uncertainty in the field of model-output. In the modelling of sewer system overflow emissions, a lot of uncertainties are involved: uncertainties about the spatial rainfall-input, model simplifications of the sewer system and runoff catchment, and biases and uncertainties about the model parameters.
A methodology has been presented to quantify the different uncertainty-sources in a decomposed way by separating uncertainties about the model structure, the model input and the model parameters. It has been applied to an existing sewer system and WWTP, for which the emission modelling has been performed both by a full hydrodynamic and a simplified conceptual model. In this application, the importance of having accurate (spatial) rainfall data and a thoroughly calibrated runoff model has been noticed. A well-considered simplification of a full hydrodynamic model, for instance by a conceptual reservoir model, has a negligible influence on modelled values of sewer system emissions. Such simplification achieves a reduction of calculation times, which is a necessity in probabilistic modelling.