bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sludge utilisation in agriculture: possibilities and prospects in Greece
Authors: Andreadakis A.D. , Mamais D. , Gavalaki E. , Kampylafka S. 
Published: May 2018

The paper presents the prospects for agricultural utilisation of the sludge produced from wastewater treatment plants in Greece and more specifically focuses on a critical review of the legislatory framework, determination of the quantitative and qualitative characteristics of the produced sludges, examination of possible sludge treatment methods and evaluation of the possibilities and prospects of sludge utilisation on the basis of the above considerations.
Landfilling is practically the only route to sludge disposal in Greece. However, in view of the anticipated future restrictions for landfilling within the European Union, this method is clearly a short-term solution and alternative options, including agricultural reuse, must be implemented. The results of a recent survey are presented and discussed in relation to this need.
Adaptive multiscale principal components analysis for online monitoring of wastewater treatment
Authors: Lennox J. , Rosen C. 
Published: May 2018

Fault detection and isolation (FDI) are important steps in the monitoring and supervision of industrial processes. Biological wastewater treatment (WWT) plants are difficult to model, and hence to monitor, because of the complexity of the biological reactions and because plant influent and disturbances are highly variable and/or unmeasured. Multivariate statistical models have been developed for a wide variety of situations over the past few decades, proving successful in many applications. In this paper we develop a new monitoring algorithm based on Principal Components Analysis (PCA). It can be seen equivalently as making Multiscale PCA (MSPCA) adaptive, or as a multiscale decomposition of adaptive PCA.
Adaptive Multiscale PCA (AdMSPCA) exploits the changing multivariate relationships between variables at different time-scales. Adaptation of scale PCA models over time permits them to follow the evolution of the process, inputs or disturbances. Performance of AdMSPCA and adaptive PCA on a real WWT data set is compared and contrasted. The most significant difference observed was the ability of AdMSPCA to adapt to a much wider range of changes. This was mainly due to the flexibility afforded by allowing each scale model to adapt whenever it did not signal an abnormal event at that scale. Relative detection speeds were examined only summarily, but seemed to depend on the characteristics of the faults/disturbances. The results of the algorithms were similar for sudden changes, but AdMSPCA appeared more sensitive to slower changes.
Model reduction through boundary relocation to facilitate real-time control optimisation in the integrated urban wastewater system
Authors: Meirlaen J. , Vanrolleghem P.A. 
Published: May 2018

Real time control is one of the possibilities to minimise the impact of the integrated urban wastewater system (sewer system and treatment plant) on the receiving water quality. Integrated control uses information about the river state to act in the sewer system or in treatment plant. In order to test and tune these integrated controllers, a simplified integrated model is needed. Even with these simplified models, the simulation times may be too long and further model reduction is needed.
In this paper, dependency-structure based model reduction is proposed as a technique to further reduce model complexity. Three steps are proposed: relocation of the upstream system boundaries to just upstream of the first control point, relocation of the downstream boundaries to just downstream of the last measurement point, and third, a further model simplification based on an analysis of the sensitivity of the control actions on submodel elimination. The effect of applying the different reduction approaches on the control strategy and on the resulting river water quality is discussed on the basis of a case study of the catchment of Tielt.
Practical identification of the dissolved oxygen dynamic in activated sludge plants
Authors: Suescun J. , Ayesa E. 
Published: May 2018

This paper presents the application to a full-scale waste water treatment plant (WWTP) of a practical methodology to identify the oxygen supply and consumption terms, which regulate the dynamic behaviour of the dissolved oxygen concentration (SO) in activated sludge reactors. This methodology is based on a periodic adjustment of the selected model for oxygen mass-transfer coefficient (KLa) and a continuous estimation of the oxygen uptake rate (rO), maintaining constant the adjusted KLa model, in order to uncouple the effects that the consumption and supply terms have on the SO concentration.
The adjustment phase of the KLa model is based on typified excitations of the system through the aeration system of the plant, which allow the estimation of KLa for different values of the aeration intensity parameter, for instance, air flow rate in air diffusion systems, revolution speed in surface aerators, etc. Once the KLa model is adjusted, it is possible to evaluate the KLa value in process conditions at any time. The continuous estimation of rO is carried out starting from the oxygen mass balance in the activatedsludge reactor.
This practical methodology has been successfully verified in the Badiolegi WWTP in Azpeitia (Spain), which biological process consists of a double stage AB process, with two different aeration systems: fine pore air diffusers in the A-stage and surface aerators in the B-stage.
Sustainable development of water services industry
Authors: Magara Y. 
Published: May 2018

The world population is expected to increase up to 8 billion by 2015. Most of the cities in the world are scattered around the fresh water resources. These cities and villages have their own interests and they constitute a power order. Therefore, we have been trying to harmonize these cities and villages in the usage of fresh water resources and the discharging of wastewater as well, by using an engineering means of water treatment. However, fresh water resources, which are essential to our lives, have a constant amount of circulation with a period of one week to ten days.
The science and technology of the water environment should recognize the limit of fresh water resources for the sustainable development of society, because the water service industries are the essential infrastructure of the community. In order to implement an appropriate risk management it is necessary to identify the goal of environmental management considering the social, natural and economical conditions. The energy-dependent technologies should be reconsidered to consume less energy and undertake more resource conservation engineering. Water science and technology cannot supply all the answers, therefore more comprehensive water management systems should be developed by other sectors, such as the food production industry.
Simultaneous removal of nitrogen and phosphorus with A2/O process using immobilized media
Authors: Goto M. , Kuribayashi S. , Nonaka Y. , Yamazaki M. 
Published: May 2018

It is necessary to introduce nitrogen and phosphorus removal processes in the existing wastewater treatment plants of Fukuoka City to improve the water quality of Hakata Bay. An A2/O (anaerobic-anoxic-oxic) process using immobilized media is proposed here, as a high-end technology to meet stricter discharge standards when faced with treatment space limitations. In order to investigate the applicability of the process, a pilot-scale study using municipal wastewater was conducted. Fluidized immobilization media were added to the aerobic reactor to maintain a high concentration of nitrifying bacteria and nitrification rate. Relationships between nutrient removal performance and varied operating conditions were examined. The results of the pilot plant test indicated that the process performs well for removal of nitrogen and phosphorus. Under the condition of HRT = 8 hr, it was possible to obtain an effluent water quality as follows: T-N&lt;8.0 mg/L; T-P&lt;1.0 mg/L.
It was observed that reaction time needed for a complete nitrification was shortened by the addition of immobilized media to the aerobic reactor, and longer reaction time would be needed for a completed phosphorus uptake process other than complete nitrification in an aerobic tank. Therefore, the phosphorus uptake rate, as well as nitrification process, should be considered as one of the important factors affecting the design parameters of an aerobic reactor.
Use of image analysis to determine algal and bacterial biomass in a high rate algal pond following Percoll® fractionation
Authors: Cromar N.J. , Fallowfield H.J. 
Published: May 2018

This paper reports the results of work to allow a more accurate enumeration, and gravimetric determination, of the relative proportions of algae and bacteria within the floccular matrix present in a High Rate Algal Pond (HRAP). Methodology involving a combination of physical and chemical treatments was used and the resulting material was separated using density gradient centrifugation. The “fractions” were analysed using microscopical image analysis. Each “fraction” was categorised as containing bacteria only, algae only or an association of bacteria and algae, the relative proportions of which were then determined by image analysis to enable a “true” gravimetric determination of the algal and bacterial components of HRAP biomass for the first time. The biomass from HRAPs operated both outdoors and in a glasshouse was examined over complete operational seasons to investigate environmental effects as well as possible effects of variation in COD loading rate and retention time on cell biovolumes and cell quotients.
In this study, the accurate assessment of both algal and bacterial biomass, determined as cell volume or dry matter, in addition to measurement of carbon and nitrogen has enabled the calculation of cell quotients. This allows a direct comparison between these values obtained from a nutrient-rich system and those published values obtained from systems with various nutrient status. Conversion factors obtained may also be of value for deriving inputs for computer models for the design and operation of high rate algal ponds.
Investigation of pond velocities using dye and small drogues: a case study of the Nelson City waste stabilisation pond
Authors: Barter P.J. 
Published: May 2018

The city of Nelson, New Zealand, has a 27 hectare oxidation pond as its primary wastewater treatment facility. Recent changes in the configuration of the pond and installation of a mixer/aerator raised concerns that pond treatment rates and effluent quality may be affected by high internal pond velocities and short retention times.
This paper presents the findings of an investigation into wastewater velocity and movement within the pond using qualitative dye dispersion and tracking of small-scale “holey-sock” drogues. Simultaneous deployment of drogues and dye allowed methods to be compared, since small-scale drogues have not commonly been used in wastewater ponds. Dye dispersion was assessed using low-level aerial photography from a tethered helium blimp to track short term movement and mixing, while a datalogger and fluorometer were used to measure pond retention time. Drogue movement was tracked in conjunction with the dye study from a small boat using hand-held GPS.
The dye study found that: (i) the first portion of pond influent discharged from the pond after 37.5 hours, substantially quicker than the theoretical pond retention time of 27 days. However, the measured retention time was with a mixer in place and the theoretical time was without a mixer; (ii) the position of the paddle wheel mixer/aerator was not optimally placed for mixing the influent and a quiescent region existed adjacent to the influent point; and (iii) the low-level aerial photography was an effective method of evaluating larger pond systems.
The “holey-sock” drogue studies showed that: (i) the drogues accurately followed the movement and velocity of dyed influent within the pond; (ii) wastewater velocity and movement was dominated by the paddle wheel mixer/aerator; and (iii) wind direction had a minor influence on wastewater velocity and movement in areas not directly affected by the paddle wheel mixer/aerator.
The study demonstrated that the combined use of dye and drogues was a relatively low-cost and effective means of determining internal pond velocities and movement. Future studies using similar methods will be useful in helping validate computer-modelled movement and velocity.
Bioleaching of metals from sludges and acid production under increased metal concentrations
Authors: Bickers P.O. , Chong R.C. , Bhamidimarri R. , Killick M.G. 
Published: May 2018

To remove heavy metals from sludge and slurries the heavy metals must first be solubilised. In this study, metal bioleaching using sulphuric acid producing microorganisms is investigated. The inhibitory effects of four metals (zinc, chromium, nickel and copper) on acid production were firstly assessed for concentrations of each metal up to 1,000 mg/l. Low concentrations of zinc and chromium (50 mg/L) appear to stimulate the production of sulphuric acid but concentrations of those metals at 500 mg/L and above inhibited acid production (20 to 30% of the control rate at a concentration of 1,000 mg/L). The average sulphuric acid production of the metal free control was 0.78 g/L/day over a 10 day period. At all concentrations of nickel and copper, sulphuric acid production was suppressed and was less than 10% of the control at 250 mg/L or more after 10 days.
Activated sludge was also loaded with the four metals in individual bioleaching tests, in increments from zero up to 5,050 mg of metal/kg solids on a dry basis. In these bioleaching trials the sulphuric acid production averaged 0.9/g/L/day and the pH after 7 days was less than 2.0. Sludge copper concentrations of 3,850 and 5,050 mg/kg partially inhibited acid production (pH after 7 days was 2.4 and 2.7). The solubilisation for each metal after 7 days was Zn: 82–97%, Ni: 12–70%, Cu: 28–55%, and Cr: &lt;20%. Bioleaching of a sludge loaded with a mixture of the four metals gave peak solubilities of 99% for Zn after 3 days, 68% for Ni after 6 days, 57% for Cu after 9 days and 33% for Cr after 9 days.
Evaluating bioaccumulation of suspected endocrine disruptors into periphytons and benthos in the Tama River
Authors: Takahashi A. , Higashitani T. , Yakou Y. , Saitou M. , Tamamoto H. , Tanaka H. 
Published: May 2018

There are two major routes through which fish are exposed to endocrine disruptors (EDs); one route is through water that is a habitat; the other is through aquatic food such as algae and benthos. Few studies on the bioaccumulation of EDs in food have been conducted. Therefore, we evaluated the concentration in food of nonylphenol (NP), bisphenol A (BPA) and 17β-estradiol (E2), which were frequently detected in river water and in final discharge of Wastewater Treatment Plants (WWTPs) in Japan. We also evaluated the estrogenicity of samples using recombinant yeast.
NP concentrations ranged 0.1-0.4 mg/L in the river water, while they ranged 8-130 mg/kg-wet in the periphytons and 8-140 μg/kg-wet in the benthos. BPA concentrations ranged 0.02-0.15 μg/L in the river water, while they ranged 2-8.8 μg/kg-wet in the periphytons and 0.3-12 μg/kg-wet in the benthos. E2 concentrations ranged 0.0001-0.0076 μg/L in the water, while they ranged 0.09-2.26 μg/kg-wet in the periphytons and &lt;0.01-0.22 μg/kg-wet in the benthos.
The estrogenicity ranged 0.0001-0.0464 μg-E2equivalent/L in the water, while it ranged 3.4-66.8 μg-E2equivalent/kg-wet in the periphytons and 7.4-5458 μg-E2equivalent/kg-wet in the benthos. Bioaccumulation factors of NP are estimated as 160-650 for the periphytons, and 63-990 for the benthos, respectively. Bioaccumulation factors of BPA are estimated as 18-650 for the periphytons, and 8-170 for the benthos, respectively. Bioaccumulation factors of E2 are estimated as 64-1,200 for the periphytons, and 100-160 for the benthos, respectively. The ratios of the periphytons and the benthos to the water in terms of the estrogenicity were larger than those in terms of the chemicals. In particularly, the ratio of the benthos to the water is about 106 in the maximum. The results suggest that food may be a more important route for fish exposed to EDs in water environment.
Adhesion and releasing of Poliovirus to activated sludge of wastewater purifying plants
Authors: Nakajima M. , Uwatoko K. , Kobayashi K. , Pan I.-J. , Iwabuchi N. , Sunairi M. 
Published: May 2018

Pathogenic enteric viruses are released from infected persons through domestic wastewater to the environment. From that point of view, the knowledge of the viral behavior in wastewater purifying process is important: it is, however, still poorly understood. In this study, we reported the adhesion of Poliovirus to activated sludge samples taken from wastewater purifying plants by using a model system. More than 108 particles adhered to one gram (wet) of activated sludge, and the adhered viral particles maintained infectivity for longer period of time and showed higher thermo-resistant than the free viral particles. The adhered viral particles were released by increase of salt concentration or alkaline pH buffer as infectious particles.
The data suggest that pathogenic viruses could be enriched and maintain the infectivity in the activated sludge, and released to environments under certain conditions.
Removal of endocrine disruptors by tertiary treatments and constructed wetlands in subtropical Australia
Authors: Chapman H. 
Published: May 2018

The controversial topic of endocrine disrupting chemicals (EDC) in aquatic environments is of international and Australian significance with the need for sustainable management of water resources increasing. The issues have been highlighted on the major continents of Europe and North America but so far have received less attention in Australia. A major source of these compounds has been identified as sewage effluent, which is treated prior to release to the environment with a primary focus on pathogen and nutrient removal. Sewage effluent is a complex mixture, which can contain many organic and inorganic compounds some of which may remain after treatment processes. More recently, technologies such as ozonation, UV treatment and advanced filtration have improved the quality of effluent discharged to the environment but there are still unresolved issues relating to poorly understood chemistries relating to EDCs in effluent discharges and the possible impacts in aquatic environments and to human health.
This paper reports on an investigation of the removal from sewage effluent of selected chemicals that are known or suspected environmental endocrine disruptors (EEDs) by sand filtration, ozonation and UV treatment at the Landsborough Water Reclamation Plant in Queensland, Australia. Compounds detected in the raw effluent included pesticides, herbicides, some heavy metals and the human hormones 17bestradiol and estrone. Most of these were removed by the advanced treatments at the water reclamation plant, with only trace concentrations of some compounds present in the final effluent. Removal of toxicants by a free water surface wetland is also reported on. Some of the constraints of direct chemical measurements are discussed and some solutions proposed.
Biodegradation of aliphatic and aromatic hydrocarbons at high temperatures
Authors: Feitkenhauer H. , Märkl H. 
Published: May 2018

In this paper, the high temperature (65-75°C) biodegradation of aliphatic and aromatic hydrocarbons is investigated and kinetic parameters are derived. The shift of the physico-chemical system properties with rising temperature will be discussed in detail. For example, the solubility of naphthalene is increased by a factor of about ten if the temperature is increased from 20 to 75°C. This effect is essential to increase the bioavailability of sparingly soluble hydrocarbons. It is also demonstrated in experiments that very high oxygen transfer rates can be obtained at high temperatures in the presence of hydrocarbons.
It is shown that efficient phenol biodegradation is essential for high temperature hydrocarbon degradation because some microorganisms tend to transform phenols into polyphenols which are very inhibitory for microbial growth. A defined mixed culture adapted to phenol converted more than 90% of a mixture of phenol, hexadecane and pyrene and a very high maximal growth rate of 0.19 h−1 was determined. A yield coefficient YX/S of about 0.8 g (biomass)/g (hydrocarbons) was calculated in this experiment. In a separate experiment the influence of the hydrocarbon droplet size on the biodegradation is investigated at 70°C using a newly isolated Thermus sp. In this case, the growth on a hexadecane/pyrene mixture was described by a model based on the Monod equation and the corresponding kinetic parameters are derived.
A mixed culture was used for the bioremediation of soil in a slurry reactor. The initial contamination of 11 g/kg was lowered to about 2 g in a reactor inoculated by an immobilized culture of extreme thermophilic microorganisms, while 9 g/kg remained in a sterile control.
Field monitoring and evaluation of innovative solutions for cleaning storm water runoff
Authors: Papiri S. , Ciaponi C. , Capodaglio A. , Collivignarelli C. , Bertanza G. , Swartling F. , Crow M. , Fantozzi M. , Valcher P. 
Published: May 2018

Urbanization increases the variety and amount of pollutants transported to receiving waters. Sediment from development and new construction; oil, grease, and toxic chemicals from automobiles; nutrients and pesticides from turf management and gardening; viruses and bacteria from failing septic systems; road salts; and heavy metals are examples of pollutants generated in urban areas. Sediments and solids constitute the largest volume of pollutant loads to receiving waters in urban areas.
When runoff enters storm drains, it carries many of these pollutants with it. In older cities, this polluted runoff is often released directly into open waterways without any treatment. Increased pollutant loads can harm fish and wildlife populations, kill native vegetation, foul drinking water supplies, and make recreational areas unsafe.
The objective of the study, performed by University of Pavia (Italy), University of Brescia (Italy) and GreenTechTexas International (US), reported herein is to evaluate the use of an innovative stormwater technology (EcoDräin(tm)) to reduce pollution due to urban runoff in existing urban areas.
The paper describes the methodology and the results achieved with tests conducted in laboratory in Pavia University in Italy and in two pilot areas in Italy and in Australia to investigate the EcoDrain's effectiveness for oil and heavy metals retention and sediment trapping. In the tests performed in a marina near Sidney in Australia a reduction has been achieved in oil and grease concentration higher than 95% and a reduction in metal concentration (particularly Copper, Lead and Zinc) close to 98%.
The paper also describes the methodology of the analysis on the absorbing material after its use and the consequent determination of the most efficient and environmentally safe way to dispose of consummated absorbent.
Sewage-treatment under substantial load variations in winter tourism areas – a full case study
Authors: Winkler S. , Natsché N. , Gamperer T. , Dum M. 
Published: May 2018

The sewage-load variations in winter tourism areas are characterized by sudden increases - in the ange of a factor two to three - within only a few days at the start and the end of the tourist season, especially at Christmas. The sudden load increases occur during periods of low wastewater temperatures, which is an additional demanding factor with respect to nitrogen removal.
A full case study was carried out at WWTP Saalfelden, which is located near one of Austria's largest skiing resorts. The plant is designed for 80,000 PE and built according to the HYBRID®-concept, which is a special two stage activated sludge process for extensive nutrient removal.