bluuebunny/crossref_metadata_2025 huggingface dataset:
Adverse effects of environmental odours: reviewing studies on annoyance responses and symptom reporting
Authors: Sucker K. , Both R. , Winneke G.
Published: May 2018

Air pollution control authorities dealing with odourous emissions from industrial, municipal and agricultural activities are often faced with many complaints from the public. In Germany, the Directive on Odour in ambient air provides a regulation system for the abatement of odour annoyance. Ambient air quality standards have been established based on investigations of the relationship between ambient odour load and community annoyance reaction. This paper describes a tool for the assessment of annoyance reactions, whereby degree of annoyance is correlated with ambient odour load. Systematic exposure response relations have been established for odour annoyance responses and symptom reporting for a variety of industrial sources. However, the precision of annoyance prediction from odour exposure measures rarely exceeds r2 = 0.17 in such studies. This is partly due to the fact that person-related factors, such as age, perceived health or stress coping styles, modify exposure response relations. The contribution of intensity and unpleasantness (hedonic tone) of ambient odours as modifying the annoyance reaction is currently investigated.
Detection of the dynamics of odour emissions from pig farms using dynamic olfactometry and an electronic odour sensor
Authors: Brose G. , Gallmann E. , Hartung E. , Jungbluth T.
Published: May 2018

The dynamics of odour emissions from a pig house was investigated by olfactometry and using an electronic odour sensor. In addition, several suggested influencing factors on the odour emission were measured to get insight into the reasons for the fluctuation of the odour emission. Odour emission tended to increase over the fattening period from August to November 2000 by a factor of two to three, although temperature and air-flow rate decreased according to the seasons. Feeding caused a significant temporary rise in animal activity, dust and odour concentration resulting in an increase of odour emission. The sensor signals of an electronic odour sensor increased simultaneously and showed a good relation to the odour concentration. There is a promising potential of electronic odour sensors to detect the dynamic and the level of odour concentrations. Further investigation will be done, to ensure a standardised measuring protocol and to obtain a calibration of electronic odour sensor signals direct to odour concentrations.
Improvement of a wind-tunnel sampling system for odour and VOCs
Authors: Wang X. , Jiang J. , Kaye R.
Published: May 2018

Wind-tunnel systems are widely used for collecting odour emission samples from surface area sources. Consequently, a portable wind-tunnel system was developed at the University of New South Wales that was easy to handle and suitable for sampling from liquid surfaces. Development work was undertaken to ensure even air-flows above the emitting surface and to optimise air velocities to simulate real situations. However, recovery efficiencies for emissions have not previously been studied for wind-tunnel systems. A series of experiments was carried out for determining and improving the recovery rate of the wind-tunnel sampling system by using carbon monoxide as a tracer gas. It was observed by mass balance that carbon monoxide recovery rates were initially only 37% to 48% from a simulated surface area emission source. It was therefore apparent that further development work was required to improve recovery efficiencies. By analysing the aerodynamic character of air movement and CO transportation inside the wind-tunnel, it was determined that the apparent poor recoveries resulted from uneven mixing at the sample collection point. A number of modifications were made for the mixing chamber of the wind-tunnel system. A special sampling chamber extension and a sampling manifold with optimally distributed sampling orifices were developed for the wind-tunnel sampling system. The simulation experiments were repeated with the new sampling system. Over a series of experiments, the recovery efficiency of sampling was improved to 83-100% with an average of 90%, where the CO tracer gas was introduced at a single point and 92-102% with an average of 97%, where the CO tracer gas was introduced along a line transverse to the sweep air. The stability and accuracy of the new system were determined statistically and are reported.
Assessment of changes to saltwater/freshwater habitat from reductions in flow to the Richmond River estuary, Australia
Authors: Pierson W. L. , Nittim R. , Chadwick M. J. , Bishop K. A. , Horton P. R.
Published: May 2018

The Australian climate is highly variable and many Australian estuaries lack a seasonal pattern of freshwater flow. During periods of low freshwater inflow, saline waters enter from the ocean through the estuary mouth. These saline waters enter as density currents or as a result of tidal mixing. During periods of high freshwater inflow from the estuary catchment, salt water is flushed towards the estuary mouth. As a consequence, the saline structure of Australian estuaries can be highly variable, depending on the antecedent rainfall. The Richmond River in northern New South Wales is such an estuary.

The biota inhabiting estuaries have varying levels of freshwater and saltwater tolerance and reducing the freshwater flow into and along an estuary will favour saltwater species. However, if extractions of freshwater from an estuary are sufficiently high, freshwater habitat could be eliminated entirely for short periods (~one month) but with consequent, and perhaps long-standing, damage to the environment.

This contribution describes a new approach to quantify the impact of changes to freshwater flows to the Richmond River estuary. This approach includes a review of hydrological data gathered over the past century and includes a detailed assessment of: changes to the highly variable freshwater inflows and freshwater extraction below the tidal limit; consequent changes to the highly variable saline structure; and the risk to aquatic biota.

The crucial factors of magnitude, frequency and duration of short-term intrusions of saline water into freshwater habitat and their impact are quantified by the methods developed.
The Microcystis cyanobacteria bloom in the Swan River - February 2000
Authors: Atkins R. , Rose T. , Brown R. S. , Robb M.
Published: May 2018

In February 2000 the Swan-Canning estuary in Western Australia experienced a record bloom of the toxic cyanobacteria Microcystis aeruginosa. At its height, concentrations of M. aeruginosa reached integrated water column cell counts of 15,000/ml and formed bright green scums in sheltered bays, where counts of 130 million cells/ml were recorded. Due to public health concerns parts of the river were closed from 10 to 22 February 2000. Two unseasonably large summer rain events in early and late January 2000 created conditions for the bloom. Freshwater runoff, estimated at 270 GL, was enough to fill the Swan-Canning estuary five times over and brought with it high levels of nutrients, mainly nitrogen (>2.0mg/L TN) and phosphorus (>0.15mg/L TP). A number of methods to reduce bloom accumulations were tried, including an attempt to increase the salinity of the surface water above the critical 10 ppt level for Microcystis; using a bentonite clay and poly-aluminium chloride mixture to flocculate and sink the algae; and sucking up scums using oil spill equipment. Over 900 tonnes of M. aeruginosa were removed and safely disposed using sewage treatment facilities. The bloom collapsed when the freshwater flush subsided and seawater intrusion from the Indian Ocean re-established itself, raising the salinities above the tolerance of Microcystis.
Direct molecular hydrogen sulphide scrubbing with hollow fibre membranes
Authors: Boucil N. , Jefferson B. , Parsons S.A. , Judd S.J. , Stuetz R.M.
Published: May 2018

The emission of hydrogen sulphide is a major problem associated with anaerobic treatment of sulphate and sulphite containing wastewaters. Conventional absorbing processes, such as packed towers, spray towers or bubble columns, are all constrained by factors such as flooding and foaming. Membrane systems, on the other hand, enable independent control of the liquid and gas flow rate and a step change order of magnitude increase in the specific surface area of the contact process. The membrane acts as a gas absorber with a design similar to a shell and tube heat exchanger. On the other hand, they are limited by facets of the membrane such as its resistance to mass transfer and permselectivity, as well as its cost. The work presented in this paper refers to an absorption process based on a non-wetted hollow fibre membrane for the scrubbing of hydrogen sulphide from air, with water as the contact solvent. Results presented describe the performance of the unit in terms of overall transfer and outlet liquid concentration as a function of circulation regime, gas flow rate, liquid flow rate and specific surface area. In particular, results are presented using traditional plots of Sherwood number (Sh) against Graetz (Gr) number for the liquid flowing in the lumens, such that experimental and available empirical descriptions of the process performance are directly compared. Results suggest that, as expected, very efficient mass transfer is obtained. However, the mass transfer was found to reach a maximum value against Gr, contrary to available empirical models.
Statistical elements of predicting the impact of a variety of odour sources
Authors: Best P.R. , Lunney K.E. , Killip C.A.
Published: May 2018

Two key elements in predicting odour response are the estimation of peak (few seconds) ground-level concentrations and the evaluation of the likelihood of a consequent adverse response. Peak rather than ensemble-average concentrations are not easily predicted by current dispersion models. The required peak-to-mean ratios depend on source characteristics, downwind distance and atmospheric stability. Using recent wind-tunnel simulations for four types of sources and two atmospheric stabilities and various measures of intermittency and non-stationarity, different regimes of behaviour are resolvable. A set of peak-to-mean ratios for a specified probability of exceedance is recommended and their practicality discussed.
Odour and VOC confining in large enclosures using air curtains
Authors: Pavageau M. , Nieto E.M. , Rey C.
Published: May 2018

Experiments were conducted on a two stream air-curtain prototype designed for VOC and odour confinement in a truck unloading area. The emphasis was placed on the air supply device. Measurements using tracer gas techniques were performed to assess the effectiveness of the system in terms of air tightness. Leakage flow rate was estimated for various feeding arrangements. Flow visualisations and particle image velocimetry measurements were carried out for a better understanding of the flow dynamics. Evidence was given of the improvements brought by the herein referred to, “double flux” configuration in comparison to traditional designs. After a brief description of the experimental facility and the basic principle underlying the approach developed, the main results are reported and discussed and recommendations are drawn. Considerations about where the effort will be directed in future works are provided.
Simultaneous activated sludge wastewater treatment and odour control
Authors: Hardy P. , Burgess J.E. , Morton S. , Stuetz R.M.
Published: May 2018

Lab-scale tests were used to determine the amount of H2S that can be treated using a range of different activated sludges. Static vessels were used to study the effects of different H2S concentrations (5, 25, 50 and 75 ppm). The data indicated that odour control may be carried out using certain types of sludge, but sludge type, e.g. carbonaceous, nitrifying, with or without coagulant, affects removal efficiency. The presence of the biomass resulted in greater H2S removal than the use of wet scrubbing and the adverse effects on mixed liquor were negligible. A pilot plant was used to study the removal efficiencies of activated sludge diffusion using a typical wastewater treatment plant H2S concentration and investigated the effects that the diffusion of H2S had on the process performance. Results indicated that the levels of H2S produced by other unit processes on a wastewater treatment site (approximately 5 ppm) can be treated using activated sludge diffusion without compromising the performance of the wastewater treatment process. The only effects on the activated sludge plant observed were: (1) nitrification was interrupted briefly as H2S diffusion commenced and (2) the species' diversity in the sludge decreased.
Towards integrated catchment management, Whaingaroa, New Zealand
Authors: van Roon M. , Knight S.
Published: May 2018

The paper examines progress towards integrated catchment management and sustainable agriculture at Whaingaroa (Raglan), New Zealand. Application of the Canadian “Atlantic Coastal Action Program” model (ACAP) has been only partially successful within New Zealand's bicultural setting. Even before the introduction of the ACAP process there existed strong motivation and leadership by various sectors of the community. A merging of resource management planning and implementation processes of the larger community and that of the Maori community has not occurred. Research carried out by Crown Research Institutes has clearly shown the actions required to make pastoral farming more sustainable. There are difficulties in the transference to, and uptake of, these techniques by farmers. An examination of the socio-economic context is required. There has been a requirement on local government bodies to tighten their focus as part of recent reform. This has occurred concurrently with a widening of vision towards integrated and sustainable forms of management. This (as well as a clear belief in empowerment of local communities) has lead to Council reliance on voluntary labour. There is a need to account for the dynamic interaction between social and political history and the geological and biophysical history of the area. As part of a re-examination of sustainable development, New Zealand needs to reconcile the earning of the bulk of its foreign income from primary production, with the accelerating ecological deficit that it creates. A sustainability strategy is required linking consumer demand, property rights and responsibilities.
Agricultural odours: 25 years of reducing complaints about barns and manure storages using the minimum distance separation formulae
Authors: Fraser H.W.
Published: May 2018

Ontario in Canada has a diverse livestock and poultry industry. Two million of Ontario's eleven million residents live in rural areas, but only 5% live on livestock and poultry farms, being outnumbered by their rural, non-livestock neighbours by 20:1. The increasing size, complexity, specialisation and concentration of livestock and poultry farms coupled with rural neighbours who have little or no family or business connection to them has resulted in an escalation in the number of odour complaints about barn and manure storage locations. Ontario-developed Minimum Distance Separation I and II formulae have helped site over 100,000 non-compatible uses, such as severed lots, away from livestock and poultry facilities, and similarly sited over 20,000 barns. However, they are under review because of the need to reflect the current and anticipated state of the livestock and poultry industry, the changing needs of the rural community, and to make it easier to apply for the growing number of municipal staff with little knowledge of the agricultural industry.
Institutional barriers and opportunities: processes and arrangements for natural resource management in Australia
Authors: Dovers S.
Published: May 2018

While “institutional failure” is commonly cited as a core barrier to sustainable resource management, operational prescriptions or criteria for institutional design are rare. Institutions are crucial, and may be barriers or opportunities. This article offers some principles and design features for “adaptive” institutions, capable of balancing the core principles of persistence, purposefulness, information-richness, inclusiveness and flexibility. It then draws on emerging findings from recent Australian research to identify some major institutional barriers and opportunities for improving capacities in sustainable resource management.
Biotreatments of odours: control and performances of a biofilter and a bioscrubber
Authors: Le Cloirec P. , Humeau P. , Ramirez-Lopez E.M.
Published: May 2018

Biotechnology has been applied to find systems to decrease the level of pollution. The main biological systems used in the deodorisation of waste gases are biofilters, biotrickling filters and bioscrubbers. These technologies work at normal operating conditions of temperature and pressure, and therefore they are relatively cheap with high efficiencies when the waste gas is characterised by high flow and low concentrations of odorous compounds. The aim of this work was to study the influence of different parameters (residence time of the gas phase, pollutant loads) of a biofilter and a bioscrubber on removal efficiencies. Ethanol was used as pollutant compound, because it is representative of both volatile organic compounds and odorous molecules. The performances of the two biological systems are presented and discussed. The use of pressure drop monitoring as a tool to control the operation of a biofilter and to obtain optimal conditions in a bioscrubber is proposed.
Establishing an Integrated Catchment Management (ICM) program in East Java, Indonesia
Authors: Booth C. A. , Warianti A. , Wrigley T.
Published: May 2018

The Brantas is one of Indonesia's most important catchments. It is the “rice bowl” of Java and nationally important for its industrial activity. Surabaya, Indonesia's second largest city, is located at the mouth of the Brantas River which is pivotal to the city's water supply. The challenges associated with the institutional framework for natural resource management in East Java parallels that of many states and provinces around the globe. It is multi-layered and complex.

Integrated Catchment Management (ICM) may be defined as “the co-ordinated and sustainable management of land, water, soil vegetation, fauna and other natural resources on a water catchment basis”. Over a period of six months, an ICM Strategy was researched and facilitated for the Brantas River Catchment in East Java via a short term advisor attachment. The aim of the Strategy is to improve co-ordination, co-operation, communication and consistency of government and community efforts towards sustaining the catchment's environmental, economic and social values. The attachment was part of the Pollution Control Implementation (PCI) Project funded by AusAid and the Indonesian Government.

The ICM Strategy developed was broad based and addressed the priority natural resource management issues facing the Brantas Catchment. It was co-ordinated by BAPEDALDA, the Provincial Environmental Protection Agency, and developed by all agencies involved in natural resource management in the catchment. Various Universities and Non Government Organisations (NGOs) were also involved in the ICM process which developed the Strategy. At the conclusion of the attachment, a draft ICM Strategy and a proposed institutional framework had been developed. A working group of key agencies was also established to further enhance local “ownership”, finalise timescales and implementation responsibilities within the Strategy and bring the institutional arrangements into being through a Governor's Decree.
What makes catchment management groups “tick”?
Authors: Oliver P.
Published: May 2018

The work of catchment management groups throughout Australia represents a significant economic and social investment in natural resource management. Institutional structures and policies, the role of on-ground coordinators, facilitation processes, citizen participation and social capital are critical factors influencing the success of catchment management groups. From a participant-researcher viewpoint, this paper signposts research directions and themes that are being pursued from the participant/coordinator, catchment group, and lead government/non-government agency perspective on the influence of these factors on the success of a catchment management group in the Pumicestone Region of Southeast Queensland, Australia.

Research directions, themes and discussion/reflection points for practitioners include - the importance of understanding milieu; motivation; success; having fun; "networking networks"; involvement of "non-traditional" stakeholders; development of stakeholder/participant partnerships; learning from other practitioners; methods of stakeholder/participant representation; evaluation; the need for guiding principles or philosophy; the equivalence of planning, implementation, evaluation, and resourcing; catchments as fundamental units of Nature; continuity of support for groups; recognising a new role for government; working with existing networks; and the need for an eclectic approach to natural resource management.
Biofiltration of dichlorobenzenes
Authors: Roberge F. , Gravel M.J. , Deschênes L. , Guy C. , Samson R.
Published: May 2018

The use of air biofiltration for the degradation of dichlorobenzenes (1,2-DCB and 1,4-DCB) was studied at a refinery site. At this plant, 93 m3/h of contaminated groundwater, used in a cooling system and containing a maximum of 2 ppm of dichlorobenzenes, had to be treated. Stripping of the DCBs followed by biofiltration was selected as the most suitable technology to avoid volatilization in ambient air as expected with a wastewater aerobic treatment system. A stripper of 15 m height and 1.27 m diameter was designed as a first step treatment to volatilize DCBs with 3400 m3/h of air. Two full-scale biofilters of 70 m3 each were built and filled with 45 m3 of filtering media for the adsorption and biodegradation of the DCBs in the gas-phase. Filtering media was composed mainly of peat moss, with animal manure, wood chips and DCBs contaminated soil. Air to be treated was also contaminated with naphthalene. Laboratory tests showed an effective microbial activity in the contaminated soil and in the filtering media for DCBs degradation. Degradation of naphthalene induced slower degradation of DCBs. Full-scale operation was studied during four months. Water flow and DCBs content in the water entering the stripper were lower than expected with only 57 m3/h and a maximum concentration of only 240 ppb. Effective desorption was obtained in the stripper in the full-scale operation (more than 99% removal). Full-scale biofilters maintained a DCB concentration of less than 1 ppmv in the air outlet, but removal efficiency varied between 0 and 79% because of the low DCB inlet concentrations, load variations and sporadic naphthalene presence.
A pilot study of a biotrickling filter for the treatment of odorous sewage air
Authors: Wu L. , Loo Y.-Y. , Koe L.C.C.
Published: May 2018

The nuisance impact of air pollutant emissions from wastewater treatment plants (WWTPs) is a major issue of concern to Singapore and to many developing cities worldwide. Existing chemical and physical treatment methods are efficient but costly, and may generate secondary pollutants. Biotreatment, on the other hand, is a proven control technology for effectively removing hydrogen sulphide (H2S), the principal odour component of sewage air. The biotechnology is cost-effective to remove low-concentrations of biodegradable compounds from a large flow of waste gases. A pilot-scale biotrickling filter, packed with pall rings, was set up at a WWTP in Singapore to investigate its effectiveness for treatment of odorous sewage air. A series of experiments were conducted to assess the performance of the biotrickling filter under various operating scenarios. Results indicated that even at 5 second gas retention time, the biotrickling filter could remove 95% of the inlet H2S. The behaviour of the biotrickling filter under various operating scenarios are presented and discussed in this paper.
Removal of hydrogen sulfide and methyl mercaptan by a packed tower with immobilized micro-organism beads
Authors: Pinjing H. , Liming S. , Zhiwen Y. , Guojian L.
Published: May 2018

To develop a more effective process for removing H2S and methyl mercaptan (MeSH), which are the important odorous components emitted from wastewater treatment facilities, a packed bed filled with immobilized micro-organism beads was studied. This study encompassed bacteria enrichment, evaluation of bacteria immobilization methods, determination of optimum operation parameters, such as environmental conditions for bacteria growth, removal rate of the packed bed etc. The experimental results are shown as follows: (1) the cultures able to metabolize H2S and MeSH can be enriched from activated sludge and the enrichment periods are 1-2 days and 7-10 days for H2S and MeSH, respectively; (2) the key environmental parameter influencing the cultures is pH value, the suitable ranges are 2-3 and 6-8 for H2S and MeSH, respectively; (3) the maximum removal rate for H2S and MeSH are 6500 g/m3 bed d and 4 g/m3 bed d, respectively; (4) the superficial M-M kinetics parameters are Vm: 11.2 g S/kg dry beads h and Ks: 95.8 mg/m3 for H2S, and Vm: 0.052 g S/kg dry beads h and Ks: 2.1 mg/m3 for MeSH; (5) a two-stage biofilter operated in series under different pH values is recommended, which can remove the H2S and MeSH effectively.
Hazardous organic matters in municipal sewage sludge in Taiwan
Authors: Cheng H. F. , Chen S. Y. , Lin J. G.
Published: May 2018

Application of municipal sewage sludge to agricultural land has attracted significant attention in recent years because it conserves abundant nutrients and hydrocarbons that can be used as a soil amendment. The presence of hazardous organic matters (HOMs) in sewage sludge limits the feasibility of reuse of sewage sludge. The purpose of this study was to investigate the types and the concentrations of HOMs in municipal sewage sludge in Taiwan. An efficient SFE/GC/MS method was used to determine HOMs in sludge samples. The results indicated that di-(2-ethylhexyl) phthalate (DEHP) was persistently found in both aerobically and anaerobically digested sludges. 4-nonylphenol (4-NP) was only found in anaerobically digested sludges. Both DEHP and 4-NP have been characterized as endocrine disrupting chemicals (EDCs) or environmental endorine disruptors (EEDs). It suggested that sludges containing high levels of DEHP and 4-NP need further treatment and reduction of possible impacts on the environment before their reuse as soil fertilizers.
Some economic considerations on wastewater reclamation for irrigation, with reference to the Italian situation
Authors: Nurizzo C. , Bonomo L. , Malpei F.
Published: May 2018

The purpose of this work is to check construction and operation costs for simplified post-treatment trains able to produce water displaying a quality suitable for different agricultural uses. Having in mind the quality of most of surface waters in Italy, the main parameters to control for a general purpose reclaimed water supply are microbial quality and TSS content. Therefore a contact filtration followed by disinfection is to be considered the minimum option, while the use of polishing ponds can be strictly limited in many Italian regions due to the area requirements and to the need to provide a full lining of bottom and levees. Some data referring to surface waters quality and to the Italian epidemiological situation are given. On the basis of the current Italian situation, the construction and operation cost increases due to a polishing section, downstream a standard municipal WWTP, are evaluated and the impact of different technical choices is shortly discussed (disinfection options, chemicals, etc.). Some considerations about the link existing in Italy between the cost of water for irrigation and the agricultural economy are made.
How partial nitrification could improve reclaimed wastewater transport in long pipes
Authors: Delgado S. , Álvarez M. , Rodríguez-Gômez L. E. , Elmaleh S. , Aguiar E.
Published: May 2018

Reclaimed wastewater transport is studied in a concrete-lined cast iron pipe, where a nitrification-denitrification process occurs. The pipe is part of the Reuse System of Reclaimed Wastewater of South Tenerife (Spain), 0.6 m in diameter and 61 km long. In order to improve wastewater quality, at 10 km from the inlet there is injection of fresh water saturated in dissolved oxygen (DO), after which a fast nitrification process usually appears (less than two hours of space time). The amount of oxidized nitrogen compounds produced varies between 0.8 and 4.4 mg/l NOX--N. When DO has disappeared, a denitrification process begins. The removal of nitrite is complete at the end of the pipe, whereas the nitrate does not disappear completely, leaving a concentration of about 0.4-0.5 mg/l. For a COD/NOX--N ratio higher than 5, a first order nitrification rate in NOX--N has resulted, with the constant k20 = 0.079 h-1, for a NOX--N concentration range of 0.8-4.4 mg/l. Finally the following temperature dependency for the first order denitrification rate constant has been found : k = k20.1×15T-20. Although nitrogen could be used as nutrient in the agricultural reuse, its removal from reclaimed wastewater could be useful in order to diminish the chlorine needs for reclaimed wastewater disinfection.
Up-to-date modification of the anaerobic sludge digestion process introducing a separate sludge digestion mode
Authors: Sato K. , Ochi S. , Mizuochi M.
Published: May 2018

Sewage treatment plants in Japan are subjected to advanced treatment to remove nutrients and hence control eutrophication problems in lakes and bays. This paper discusses the advantages and disadvantages of the separate digestion treatment mode for sludge generated from advanced wastewater treatment. In the separate digestion only primary sludge is digested and the excess activated sludge is directly dewatered. Separate digestion can reduce the return load of nutrients to approximately one third, and has major potential for the beneficial use of sludge.
Floc structure and the role of cations
Authors: Novak J.T. , Muller C.D. , Murthy S.N.
Published: May 2018

Cations have been found to influence the settling and dewatering characteristics of biological sludges. This research was directed at investigating the role of iron in floc stability of sensitivity to shear and in the response to anaerobic and aerobic digestion. Our data shows that iron may contribute to floc strength and it appears that the deterioration in sludge dewatering during anaerobic digestion is associated with the reduction and solubilization of iron. Further, it is the presence of proteins in solution that contributes to poor dewatering and to the demand for conditioning chemicals. The addition of iron for improving dewatering shows that iron may selectively coagulate solution proteins.
Evaluation of an integrated membrane system for water repurification
Authors: Gagliardo P. , Adham S. , Olivieri A. , Trussell R.
Published: May 2018

An integrated membrane system was evaluated for water repurification. Performance evaluation of the membrane system was based on three criteria: flux and fouling, disinfection capability, and rejection of pollutants. Minimal membrane fouling was observed for all of the membranes employed in the study. Significant contaminant rejection was also achieved by the membrane system purifying the reclaimed water to meet and exceed drinking water standards. Wide range of virus rejection was observed for the membranes, which was dependent on the membrane type, manufacturer, and the fouling status. Overall, the results of this study demonstrated that the integrated membrane system is a very effective and reliable process for water repurification.
Demonstration, the solution to successful community acceptance of water recycling
Authors: Gibson H. E. , Apostolidis N.
Published: May 2018

The Department of Natural Resources in Queensland, Australia are presently carrying out a comprehensive Strategy called the Queensland Water Recycling Strategy (QWRS) to determine future Government directions in the whole area of water recycling. This strategy is considering the beneficial use of all waste streams such as domestic sewage, industrial and agricultural wastes, as well as urban stormwater. Following a workshop held during the initial phase of the strategy it was determined that a high priority must be given to the demonstration of recycling practices not being utilised in the State, or presently being practiced in an unsustainable manner. Three separate types of recycling projects are being carried out, the first being based on demonstrating recycling on a large new urban development close to Brisbane, the second associated with demonstrating the complex treatment processes associated with the higher levels of recycling, and the third associated with demonstrating community based recycling schemes.
Source water impact model (SWIM) - a watershed guided approach as a new planing tool for indirect potable water reuse
Authors: Drewes J. E. , Fox P.
Published: May 2018

The scope of this study was to develop a model to assess the impact of source water quality on reclaimed water used for indirect potable reuse. The source water impact model (SWIM) considered source water qualities, water supply distribution data, water use and the impact of wastewater treatment to calculate reclaimed water quality. It was applied for sulfate, chloride, and dissolved organic carbon (DOC) at four water reuse sites in Arizona and California. SWIM was able to differentiate between the amount of salts derived by drinking water sources and the amount added by consumers. At all sites, the magnitude of organic residuals in reclaimed water was strongly effected by the concentration of organics in corresponding water sources and effluent-derived organic matter. SWIM can be used as a tool to predict reclaimed water quality in existing or planned water reuse systems.
Stabilization of heavy metals on spent fluid catalytic cracking catalyst using marine clay
Authors: Sun D.D. , Tay J.H. , Qian C.E.G. , Lai D.
Published: May 2018

Spent fluid catalytic cracking catalyst is a hazardous solid waste generated by petroleum refineries containing vanadium and nickel. The marine clay was used as a matrix to stabilize vanadium and nickel and produce bricks which were then fired at various temperatures. TCLP leaching tests indicated that stabilizing brick had low metal leaching, with a maximum of 6.4 mg/l for vanadium and 19.8 μg/l for nickel. Compressive strength of stabilizing brick was found to range between 20 N/mm2 and 47 N/mm2. It is believed that stabilization and encapsulation mechanisms are responsible for the stabilization of vanadium and nickel. Encapsulation is a process whereby the marine clay matrix forms a physical barrier around the heavy metals which are thus prevented from leaching out into the environment. Incorporation involves the formation of bonds between the marine clay matrix and the heavy metals which thus become incorporated in the clay microstructure.
Using seafood waste as sludge conditioners
Authors: Lee D.Y. , Jing S.R. , Lin Y.F.
Published: May 2018

In this study, three kinds of seafood wastes (shrimp shell particles, oyster shell particles, and internal bone particles of squid) were added to dewatered sludge preconditioned with chemical conditioner (alum or ferric chloride). The specific resistance of sludge dewatering was calculated to evaluate the effectiveness of sludge dewatering. The result showed that adding chemical conditioners alone caused noticeable pH decrease and resulted in a conditioned sludge with poor filterability. The addition of oyster shell or internal bone of squid to chemically preconditioned sludge efficiently improved sludge dewatering. This result was possibly due to both the availability of alkaline and the function as skeleton builder provided by these two waste solids. Particle sizes (0.59-2.0 mm) of oyster shell and internal bone of squid were found to have insignificant effect on sludge dewatering.
Improved performance of a chitosan-based adsorbent for the sequestration of some transition metals
Authors: Navarro R. R. , Tatsumi K.
Published: May 2018

Polyethyleneimine (PEI) was chemically introduced onto chitosan by its reaction with epoxide groups of grafted poly(glycidyl methacrylate) (poly(GMA)) chains for enhanced metal chelating properties and improved physical stability in acidic conditions. Graft polymerization of poly(GMA) onto chitosan was initiated by Ce(IV) ammonium nitrate (CAN). Infrared spectroscopy revealed the presence of significant epoxide groups to confirm the success of both grafting and amination stages. Batch adsorption experiments showed the higher affinity of the modified chitosan resin for Cu2+, Zn2+ and Pb2+. The capacity enhancement was even more pronounced in the case of Zn2+ and Pb2+, which exhibits more complicated three dimensional coordination requirements. Optimum metal adsorption occurs at above pH 4. Regeneration of the resin with sulphuric acid-ammonium sulphate was also found to be feasible.
Polyvinyl alcohol as an immobilization matrix - a case of gold biosorption
Authors: Khoo K.-M. , Ting Y.-P.
Published: May 2018

The use of polyvinyl alcohol (PVA) as a matrix for cell immobilization has been extensively studied in various biological systems. However, its suitability has not been reported in biosorption studies where inactivated cells are used as biosorbents. In this work, PVA and alginate as immobilization matrices (for the biosorption of gold by a fungal biomass) were investigated by examining their physical and chemical properties. Compared to alginate gels, PVA gels were shown to be more resistant to mechanical abrasion, and more stable over a wide pH range. Although the PVA matrix did not affect the equilibrium uptake in gold biosorption studies, the time required to attain a removal of 80% of the initial metal concentration was 1.7 times that of the freely suspended biosorbent. This contrasts with the alginate immobilized biosorbent which required an increase of well over ten times the duration to attain the same removal efficiency. Results indicated that PVA gels conferred a lower mass transfer resistance than alginate gels. Gold biosorption by the PVA-immobilized fungi followed the commonly used Langmuir and Freundlich adsorption isotherm models although the former gave a better fit. The uptake of gold was dependent on the initial gold concentration and the biomass loading. Using a fungal biosorbent and gold ions as the model system, the results demonstrate the potential in the use of the PVA as a cell immobilisation matrix for biosorption studies.
Influence of pre-treatments and recycled flows on the COD fractions of a wastewater: a case study
Authors: Anderson E. , Ginestet P. , Spérandio M. , Paul E.
Published: May 2018

Physical-chemical and biological fractionation methods were used at different parts of the Evry WWTP in order to assess the influence of effluents recycled from the primary settling tanks and sludge treatment processes on the characteristics of the wastewater. The RBCOD doubled between the WWTP influent and the biological reactor inlet, thus doubling the denitrifying potential of the plant. The primary sludge gravity thickener effluent, subject to a great variability, appeared to contribute up to 38% of the RBCOD contained in the biological reactor influent, whereas only 30% seemed to come from the WWTP inlet. No notable increase of RBCOD was observed at the primary settling tanks' outlet for the longer residence time. The significant variations of RBCOD across the plant were not caused by fluctuations of the physical-chemical COD fractions.
Transfer number in fine bubble diffused aeration systems
Authors: Capela S. , Roustan M. , Héduit A.
Published: May 2018

On the basis of full-scale data from 58 clean water tests performed in 26 activated sludge tanks equipped with fine bubble diffusers and of a theoretical approach, it can be stated that fine bubble aeration systems with total floor coverage arrangement provide higher kLa values and the lowest spiral liquid circulation.

An efficiency criterion for oxygen transfer ( NT) was defined on the basis of the dimensional analysis. The transfer number NT allows us to take account of the impact of vertical liquid circulation movements on oxygen transfer. The values of NT calculated from the results of full scale nonsteady-state clean water tests vary from 5.3×10-5 to 9.1×10-5 and are directly dependent upon the arrangement of air diffusers. It has been shown that the highest transfer numbers corresponded to the total floor coverage arrangement and the average calculated NT values is 7.7×10-5, independently of the diffuser density and of the gas velocity, over the ranges studied. The lowest transfer numbers are obtained when the diffusers are located in separate grids, and the transfer number is reduced with increasing air flow rate.
Field observations of dilution on the Ipanema Beach outfall
Authors: Roldão J. , Carvalho J. L. B. , Roberts P. J. W.
Published: May 2018

Field observations of the Ipanema Beach, Rio de Janeiro, ocean sewage outfall are presented. Measurements of dilution and other wastefield characteristics were obtained by adding dye tracer to the effluent and measuring in-situ. Simultaneous measurements of oceanographic conditions were made by Acoustic Doppler Current Profilers, thermistor strings, and profiling instruments. Four experiments were performed, two during unstratified conditions when the plume was surfacing, and two during conditions of strong stratification when the plume was submerged. The minimum dilution varied from 30 to 130. The measurements reflect the worst case conditions as the campaigns were all made for weak currents.
Tirane, Albania: survey on drinking water quality and facilities
Authors: Palombi L. , Villa L. , Divizia M. , Cenko F. , Siniari V. , Rotigliano G. , Buonomo E.
Published: May 2018

To develop a realistic model of the situation, a study was carried out in four different socio-economic and hygienic areas of Tirane, namely in the modern and historical centre as well as in the intermediate and peripheral areas. In each area interviewers from the city's Public Health Directorate, contacted randomly, door-to-door, the residents, submitting a questionnaire and collecting water samples at the same time. Our data show relevant differences regarding distribution and quality of drinking water between the centre and peripheral areas. One third of water samples revealed the presence of microorganisms, whereas one fifth had no residual chlorine. Altogether more than 200,000 people in the peripheral areas of Tirane live under low level hygienic conditions. The recent outbreaks of cholera, poliomyelitis and the hyperendemic hepatitis A disease are the dramatic results of the low quality drinking water .
The effect of temperature on the efficacy of ozonation for inactivating Cryptosporidium parvum oocysts
Authors: Hirata T. , Shimura A. , Morita S. , Suzuki M. , Motoyama N. , Hoshikawa H. , Moniwa T. , Kaneko M.
Published: May 2018

Examination of the effects of water temperature on the inactivation of Cryptosporidium parvum oocysts with ozone, ozonation experiments were conducted in a semi-batch mode with a wide temperature range of 3-30°C. Inactivation was assessed in terms of mice infectivity and in vitro excystation. The temperature dependency of the CT products by a reduction in infectivity of 2 log10 could be described successfully by the Arrhenius equation, 1/CT=1.086×1018 e-12520/K where CT is the integrated ozone concentration over the contact time (mg/min/L) and K is the Kelvin temperature of water. As for the reduction in viability assessed by the excystation assay, protocol B, the obtained regression equation, 1/CT=1.802×1018 e-12640/K, was almost identical to that observed for the infectivity. Thus, the CT products required for a 2 log10 reduction in both infectivity and viability increased by an average factor of 4.2 for every 10°C decrease in water temperature. Additionally, our findings suggested that the viability, as determined by protocol B, could substitute for animal infectivity in evaluating the effects of environmental factors on the efficacy of ozonation.
A model-based approach to predicting BOD5 in settled sewage
Authors: Brydon D. A. , Frodsham D. A.
Published: May 2018

Rapid, accurate and reliable measurements of BOD are a very desirable basis for monitoring and controlling wastewater treatment works. Unfortunately, however, producing satisfactory measurements using hardware instrumentation has proved difficult. This paper addresses the issue of BOD estimation using a model-based approach. Two models are developed from historical data using neural network methods. The first model estimates the five-day BOD of the settled sewage using flow, solids, chloride and ammonia data and produces accurate predictions. The second model uses only flow and solids data as inputs yet still produces acceptable (although less accurate) predictions. It was concluded from this that satisfactory estimates of five day BOD can be produced using information that is relatively common to most works. The models are straightforward to apply on-line and offer a method of estimating five day BOD in real-time that is likely to be cheaper, more reliable and easier to maintain than hardware instrumentation.
Performance of the full-scale biological nutrient removal plant at Noosa in Queensland, Australia: nutrient removal and disinfection
Authors: Urbain V. , Wright P. , Thomas M.
Published: May 2018

Stringent effluent quality guidelines are progressively implemented in coastal and sensitive areas in Australia. Biological Nutrient Removal (BNR) plants are becoming a standard often including a tertiary treatment for disinfection. The BNR plant in Noosa - Queensland is designed to produce a treated effluent with less than 5 mg/l of BOD5, 5 mg/l of total nitrogen, 1 mg/l of total phosphorus, 5 mg/l of suspended solids and total coliforms of less than 10/100 ml. A flexible multi-stage biological process with a pre-fermentation stage, followed by sand filtration and UV disinfection was implemented to achieve this level of treatment. Acetic acid is added for phosphorus removal because: i) the volatile fatty acids (VFA) concentration in raw wastewater varies a lot, and ii) the prefermenter had to be turned off due to odor problems on the primary sedimentation tanks. An endogenous anoxic zone was added to the process to further reduce the nitrate concentration. This resulted in some secondary P-release events, a situation that happens when low nitrate and low phosphorus objectives are targeted. Long-term performance data and specific results on nitrogen removal and disinfection are presented in this paper.