bluuebunny/crossref_metadata_2025 huggingface dataset:
Cost effective and advanced phosphorus removal in membrane bioreactors for a decentralised wastewater technology
Authors: Gnirss R. , Lesjean B. , Adam C. , Buisson H.
Published: May 2018

Future stringent phosphorus regulations (down to 50 mg/L in some cases) together with the availability of more cost effective and/or innovative membrane processes, are the bases for this project. In contrast to conventional activated sludge plants, process parameters are not optimised and especially enhanced biological phosphorus (Bio-P) removal in membrane bioreactors (MBRs) are not proven yet. Current practice of P-removal in MBRs is the addition of coagulants in a co-precipitation mode. Enhanced biological phosphorus removal, when adapted to MBR technology, might be a cost-effective process. For very stringent effluent criteria additional P-adsorption on activated clay after membrane filtration can be also an interesting solution. The objective of this research project is to identify and test various phosphorus removal processes or process combinations, including MBR technologies. This should enable us to establish efficient and cost effective P-removal strategies for upgrading small sewage treatment units (up to 10,000 PE), as needed in some decentralised areas of Berlin. In particular, enhanced Bio-P removal technology was developed and optimised in MBR. Combinations of co-precipitation and post-adsorption will be tested when low P-values down to 50 mg/L are required in the effluent. One MBR bench-scale plant of 200 to 250 L and two MBR pilot plants of 1 to 3 m3 each were operated in parallel to a conventional wastewater treatment plant (Ruhleben WWTP, Berlin, Germany). The MBR bench-scale and pilot plants were operated under sludge ages of respectively 15 and 25 days. In both cases, Bio-P was possible, and phosphorus effluent concentration of about 0.1 mg/L could be achieved. A similar effluent quality was observed with the conventional WWTP. Investigations with lab columns indicated that P-adsorption could lead to concentrations down to 50 mg/L and no particle accumulation occurred in the filter media. The three tested materials exhibited great differences in break-through curves. Granulated ferric hydroxyde (GEH®) showed higher capacity than activated alumina and FerroSorpPlus.
Domestic wastewater treatment by a submerged MBR (membrane bio-reactor) with enhanced air sparging
Authors: Chang I.-S. , Judd S.J.
Published: May 2018

The air sparging technique has been recognised as an effective way to control membrane fouling. However, its application to a submerged MBR (Membrane Bio-Reactor) has not yet been reported. This paper deals with the performances of air sparging on a submerged MBR for wastewater treatment. Two kinds of air sparging techniques were used respectively. First, air is injected into the membrane tube channels so that mixed liquor can circulate in the bioreactor (air-lift mode). Second, a periodic air-jet into the membrane tube is introduced (air-jet mode). Their applicability was evaluated with a series of lab-scale experiments using domestic wastewater. The flux increased from 23 to 33 lm−2h−1 (43% enhancement) when air was injected for the air-lift module. But further increase of flux was not observed as the gas flow increased. The Rc/(Rc+Rf), ratio of cake resistance (Rc) to sum of Rc and Rf (internal fouling resistance), was 23%, indicating that the Rc is not the predominant resistance unlike other MBR studies. It showed that the cake layer was removed sufficiently due to the air injection. Thus, an increase of air flow could not affect the flux performance. The air-jet module suffered from a clogging problem with accumulated sludge inside the lumen. Because the air-jet module has characteristics of dead end filtration, a periodic air-jet was not enough to blast all the accumulated sludge out. But flux was greater than in the air-lift module if the clogging was prevented by an appropriate cleaning regime such as periodical backwashing.
Use of ORP (oxidation-reduction potential) to control oxygen dosing for online sulfide oxidation in anaerobic treatment of high sulfate wastewater
Authors: Khanal S.K. , Shang C. , Huang J.-C.
Published: May 2018

In this study, oxidation-reduction potential (ORP) was used as a controlling parameter to regulate oxygen dosing to the recycled biogas for online sulfide oxidation in an upflow anaerobic filter (UAF) system. The UAF was operated with a constant influent COD of 18,000 mg/L, but with different influent sulfates of 1000, 3000 and 6000 mg/L. The reactor was initially operated under a natural ORP of -290 mV (without oxygen injection), and was then followed by oxygenation to raise its ORP by 25 mV above the natural level for each influent sulfate condition. At 6,000 mg/L sulfate without oxygen injection, the dissolved sulfide reached 733.8 mg S/L with a corresponding free sulfide of 250.3 mg S/L, thus showing a considerable inhibition to methanogens. Upon oxygenation to raise its ORP to -265 mV (i.e., a 25 mV increase), the dissolved sulfide was reduced by more than 98.5% with a concomitant 45.9% increase of the methane yield. Under lower influent sulfate levels of 1,000 and 3,000 mg/L, the levels of sulfides produced, even under the natural ORP, did not impose any noticeable toxicity to methanogens. Upon oxygenation to raise the ORP by +25 mV, the corresponding methane yields were actually reduced by 15.5% and 6.2%, respectively. However, such reductions were not due to the adverse impact of the elevated ORP; instead, they were due to a diversion of some organic carbon to support the facultative activities inside the reactor as a result of excessive oxygenation. In other words, to achieve satisfactory sulfide oxidation for the lower influent sulfate conditions, it was not necessary to raise the ORP by as much as +25 mV. The ORP increase actually needed depended on both the influent sulfate and also actual wastewater characteristics. This study had proved that the ORP controlled oxygenation was reliable for achieving consistent online sulfide control.
Accelerated landfill waste decomposition by external leachate recirculation from an old landfill cell
Authors: Suna Erses A. , Onay T.T.
Published: May 2018

This research is focused on the management of moisture regime for a young landfill site in terms of leachate recirculation which entails the containment, collection and reinjection of leachate back into the landfill to promote in situ anaerobic biological treatment. Moreover, an innovative leachate management strategy was developed by using leachate recirculation from a mature landfill site into a young landfill site to provide accelerated waste stabilization. For this purpose, two reactors simulating young and old landfills were used in the laboratory. These reactors were loaded with shredded and compacted municipal solid waste with a typical composition determined for Istanbul Region. Both reactors were operated in a constant temperature room at 32°C to enhance the growth of anaerobic microorganisms. Moreover, water was added to the reactors in order to simulate the annual rainfall. The reactor having the properties of old landfills was used as a control reactor. The reactor which represented the characteristics of young landfill was operated under four operational stages to enhance the activity of methanogenic population and accelerate waste stabilization. Results of this study indicated that the utilization of leachate recirculation enhanced waste stabilization in the young landfill by increasing the uniformity, and providing additional substrate and nutrients. Additions of buffer solutions of KOH and Na2CO3 together with leachate recirculation enhanced further waste stabilization and prevented possible acid inhibition. The utilization of external leachate recycled from the old landfill having desired acclimated anaerobic microorganisms, low organic content and higher buffer capacity into a young landfill could be a promising leachate management strategy for faster and controlled waste stabilization.
Anaerobic degradation of organic materials - significance of the substrate surface area
Authors: Palmowski L.M. , Müller J.A.
Published: May 2018

In anaerobic degradation of substrates containing mainly particulate organic matter, solids hydrolysis is rate-limiting. In these investigations, the particle size of various substrates was reduced by comminution to support hydrolysis. Two positive effects of comminution were observed. For substrates with high fibre content, which are particularly resistant to biodegradation, a significant improvement of the degradation degree was observed as a result of comminution. Secondly, for all substrates tested, and particularly for those rich in fibres, the degradation rate of comminuted samples was significantly higher.

The first reason for both effects is an increase of the sample surface area. Several methods for measuring the specific surface area of organic materials, including particle size analysis, Nitrogen-adsorption and enzyme adsorption, were used and compared for the purpose of this study, where the surface area accessible to microbial enzymes is critical. The significance of the surface area in anaerobic degradation of particulate substrates was investigated through a kinetic model where the hydrolysis rate was based on the sample surface area. Good agreements were obtained between model and experiments carried out with samples of various specific surface areas. These results reinforced the significance of the sample surface area in anaerobic degradation processes. However, other effects of comminution responsible for the increased degradation degree and degradation rate were identified and discussed. These include: the increase of dissolved compounds due to cell rupture, exposition of surface areas previously inaccessible for microbial degradation, and alteration of the sample structure such as the lignin-cellulose arrangements.
The Store and Treat process for sludge liquor management
Authors: Laurich F. , Günner C.
Published: May 2018

Process sewage from sludge dewatering is particularly suitable for separate partial-flow treatment owing to its highly concentrated components and mostly elevated temperature. The procedures normally foreseen are those offering an effective treatment plant discharge based on a simple operating method and at low cost. With the Store and Treat process developed by Hamburger Stadtentwässerung existing sludge liquor basins can be used for an additional biological partial-flow treatment at reasonable cost without abandoning the advantages of quantity management.
Evaluating integrated urban water systems alternatives for Brisbane, Australia
Authors: Mitchell G. , Gray S. , Shipton B. , Woolley R. , Erbacher J. , Egerton G. , McKnoulty J.
Published: May 2018

The Brazil Development Study investigates the feasibility of alternative approaches to providing sustainable water services to a 226 ha mixed residential and industrial greenfield development within the city of Brisbane, Australia. The alternatives include techniques such as the use of rainwater tanks, water use efficiency, a local wastewater treatment plant for recycling of reclaimed water and composting toilets amongst others. This paper evaluates a series of urban development scenarios against the objectives of the study. The insights gained into the drivers for cost and environmental impact for this particular site are discussed as well as a number of issues of concern and challenges to Council and the community.
Sustainable water cycle design for urban areas
Authors: Maher M. , Lustig T.
Published: May 2018

This paper presents the argument that the environmental, social and economic benefits of decentralised systems are such that they should present a serious alternative to centralised systems in existing and future planned urban developments. It will be shown that the combination of technical, social and regulatory factors that influenced the popularity of centralised systems has altered, and that decentralised systems should now be considered as well. The environmental, social and economic advantages and disadvantages of several sustainable watercycle case studies are examined and compared with centralised systems. The studies examined will go from large scale down to designs suitable for typical residential houses on standard urban blocks.
Sustainability concept for a newly built urban area in Malmö, Sweden
Authors: Gruvberger C. , Aspegren H. , Andersson B. , la Cour Jansen J.
Published: May 2018

National goals regarding sustainable development from the Swedish government were decisive in the planning process when the newly built city district Western Harbour was established in the city of Malmö, Sweden. A systems analysis was used as a tool for evaluating different collection and treatment systems. This type of analysis does not include more subjective factors such as acceptance of organic fertilisers based on human waste and user acceptance of collection schemes. These aspects, however, will often determine the success of a technical solution. When the system for collection and treatment of solid organic waste and wastewater was designed, both subjective and objective factors were considered. This meant that a centralised solution for wastewater treatment was selected. In order to facilitate a more sustainable solution for sludge management a treatment process with recovery of phosphorus will have to be introduced. Organic waste is sorted out and treated in an anaerobic digestion process. Source sorting of solid organic waste has been difficult to implement in Sweden due to inadequate sorting discipline. As a consequence two relatively new systems are tested in the area. A comprehensive evaluation will be carried out during a period of two years.
Wastewater services for small communities
Authors: Gray S. , Booker N.
Published: May 2018

Connection to centralised regional sewage systems has been too expensive for small-dispersed communities, and these townships have traditionally been serviced by on-site septic tank systems. The conventional on-site system in Australia has consisted of an anaerobic holding tank followed by adsorption trenches. This technique relies heavily on the uptake of nutrients by plants for effective removal of nitrogen and phosphorus from the effluent, and is very seasonal in its efficiency. Hence, as these small communities have grown in size, the environmental effects of the septic tank discharges have become a problem. In locations throughout Australia, such as rural Victoria and along the Hawkesbury-Nepean River, septic tanks are being replaced with the transport of sewage to regional treatment plants. For some isolated communities, this can mean spending $20,000-$40,000/household, as opposed to more common connection prices of $7,000/household. This paper explores some alternative options that might be suitable for these small communities, and attempts to identify solutions that provide acceptable environmental outcomes at lower cost. The types of alternative systems that are assessed in the paper include local treatment systems, separate blackwater and greywater collection and treatment systems both with and without non-potable water recycling, a small township scale treatment plant compared to either existing septic tank systems or pumping to a remote regional treatment facility.The work demonstrated the benefits of a scenario analysis approach for the assessment of a range of alternative systems. It demonstrated that some of the alternatives systems can achieve better than 90% reductions in the discharge of nutrients to the environment at significantly lower cost than removing the wastewater to a remote regional treatment plant. These concepts allow wastewater to be retained within a community allowing for local reuse of treated effluent.
Integrated environmental assessment of tertiary and residuals treatment - LCA in the wastewater industry
Authors: Beavis P. , Lundie S.
Published: May 2018

In the wastewater industry, decision-makers lack access to an environmental tool that can assist in further informing the non-financial analysis of a system. Such a tool should incorporate impacts beyond the effluent quality and look at the supporting processes of a plant as well as plant specific operations. Life Cycle Assessment can provide the means to fill a gap in pertinent information towards more sustainable decision-making. The project “Best Practice LCA in the Wastewater Industry” is commissioned by the CRC for Waste Management and Pollution Control at UNSW with representatives from Sydney Water Corporation(SWC), NSW Department of Land and Water Conservation and the NSW Department of Public Works. Two case studies were researched to provide a post-implementation review of changes in wastewater treatment.

Case study 1: The conversion from chlorine gas to hypochlorite and UV disinfection has been completed for several inland wastewater plants at SWC. A review of operational data for each of the options has been incorporated into an LCA of each technology. Under efficient dosing conditions, disinfection with the hypochlorite system has the minimum environmental impact.

Case study 2 deals with the conversion from anaerobic to aerobic digestion. Aerobic digestion minimises release of nutrients into a sidestream to be further treated in the plant. However conversion results in more biosolids production and higher electricity requirements. This study includes a consideration of the environmental impacts of biosolids production and application. On the basis of the extended system boundary including consideration of reflux composition, energy requirements and biosolids quality to potentially offset fertiliser production, anaerobic digestion performs best in 6 out of 9 impact categories.

These results suggest that environmental LCA has a role in informing decision-making on unit process and treatment train selection by quantifying aspects on non-financial criteria. Also, improvement potentials are foreshadowed but not detailed.
The effects of humic substances on the intake of micro-organic pollutants into the aquatic biota
Authors: Matsubara J. , Takahashi J. , Ikeda K. , Shimizu Y. , Matsui S.
Published: May 2018

Humic substances, naturally occurring highly polymerized organic compounds, exist widely in the water and soil environments. It has been known that the humic substances affect the fate of micro-organic pollutants (e.g. intake, accumulation, movement, degradation, toxicity, etc.). Of these, the effect of humic substances on the intake into biota (i.e. living cell) is one of the most important. In this research, the effects of co-existing humic substances on the intake of micro-organic pollutants into aquatic biota were experimentally evaluated. The humic acid filtrate using a 3,000 Da ultra-filtration membrane was used. Two PAHs (i.e. pyrene and phenanthrene) were used as micro-organic pollutants. Liposome for simulating living cell membrane was synthesized in the laboratory, and used for investigating the intake of micro-organic pollutants into aquatic biota precisely. The batch experiment results (PAHs onto humic acid, humic acid into liposome, and PAHs into liposome (Klipw)) led to the fact that the sorption of PAHs into liposome is suppressed apparently by binding with humic acid in the aqueous phase. This suggests that the accumulation and/or toxicity of micro-organic pollutants is retarded by humic substances in the actual aqueous environment. Moreover, the experimental results indicated that the sorption into liposome (i.e. liposome/water partition coefficient (Klipw)) could be a better parameter for estimating the intake of micro-organic pollutants into aquatic biota than n-octanol/water partition coefficient (Kow) in the aqueous environment.
Ordination and classification of macroinvertebrates and environmental data of a stream in Turkey
Authors: Girgin S. , Kazanci N. , Dügel M.
Published: May 2018

Macroinvertebrate communities and environmental variables were assessed in an Ankara Stream receiving high organic and industrial wastes. Environmental data were used to explain biological variation using multivariate techniques provided by the program CANOCO. The ordination method CCA (Canonical Correspondence Analysis) was applied to evaluate the relationships between environmental variables and distribution of macroinvertebrate genera. Data sets were classified by TWINSPAN (Two Way Indicator Species Analysis). In this investigation, macroinvertebrate communities have been shown by CCA ordination to be related to TOM (total organic matter), ammonia, cadmium, pH, lead, dissolved oxygen, conductivity (EC), phosphate, boron, nitrite and hardness, with TOM, ammonia, cadmium and pH emerging as the most significant environmental variables. Epeorus was a TWINSPAN indicator for the slightly polluted upstream site 1. Physa was a TWINSPAN indicator for the polluted downstream sites.
River basin management, described for the example of the Emschergenossenschaft
Authors: Baumgart H.-C. , Sperling F. , Stemplewski J.
Published: May 2018

Considerable problems concerning drainage capacity made it necessary, at the beginning of the 20th Century, to make a joint public-private effort, because the existence of the Ruhr Area as an industrial location was endangered. By Prussian law a co-operative was established for wastewater and drainage-management of the entire Emscher river system. In the past the Emscher Association and the later founded Lippe Association have proved to be the best instrument to cope with the wastewater problems of a densely-populated industrial area. In recent time, the Emscher area is undergoing fundamental structural changes. To increase its attractiveness increased efforts are needed for a modernisation of the wastewater transport and treatment system. To deal with the various and complex tasks to reshape the Emscher system, the joint association again provides a highly efficient and competent instrument.
Fast online determination of surfactant inhibition in acidic phase bioreactors
Authors: Feitkenhauer H.
Published: May 2018

Surfactants have been shown to inhibit the anaerobic digestion process severely, with the methanogenic microorganisms being the most affected. The diverse nature of surfactants used even in one (e.g. textile finishing) plant makes an online determination of surfactants sometimes very difficult and expensive. Therefore a fast online determination of inhibitory effects on the acidogenic microorganisms (first step of the degradation cascade) can help to give an early warning signal or to calculate a "pseudo"-surfactant concentration. In a two-phase system this information can be used to protect the methanogenic reactor against surfactant overloading and its long term negative effects. In this paper it is shown that the inhibition is a consequence of microbial inhibition and is not caused by an inactivation of extracellular hydrolytic enzymes (released by the cells for biopolymer cleavage). A titration technique was successfully employed to measure the surfactant inhibition in a laboratory-scale acidification reactor. Additional experiments demonstrate (using sodium dodecyl sulfate as the model substance) how inhibitory effects (and strategies to overcome inhibitory effects) can be investigated efficiently.
Modeling of the acclimation/deacclimation process of a mixed culture degrading 4-chlorophenol
Authors: Buitrón G. , Moreno J.
Published: May 2018

The variation of concentration of the toxic substrate has a negative effect on the sludge activity. Although this loss of activity of the microorganisms under toxic starvation has been reported, this variable is not taken into account in the operation of biological wastewater treatment plants. In order to monitor and control the biological plant with a certain confidence it is necessary to consider the acclimation and deacclimation processes to avoid the reactor malfunctioning, resulting in loss of efficiency or in false data acquisition during monitoring. This paper proposes a model for the acclimation/deacclimation process. The experiments have been done in a sequencing batch reactor during the 4-chlorophenol degradation. The basic idea of the model is to consider the variation of the kinetic parameters of the Haldane law in terms of the acclimation and deacclimation state. The idea is discussed, and the results obtained are presented.
Measuring changes in water-related health and hygiene practices by developing-community households
Authors: Jagals P. , Nala N.P. , Tsubane T.J. , Moabi M. , Motaung K.C.
Published: May 2018

A population sample from a community in a developing urban area (Botshabelo), which obtains its treated water supply from a communal standpipe system, was subjected to a short Health and Hygiene Awareness and Education (HHA&E) programme to improve its practices on storing water in, and handling water from, storage containers at home. The problem was that the community's practices lead to the deterioration of the microbiological quality of the water in domestic storage containers. Measuring changes in the practices, as well as the microbiological quality of water in the containers, were the instruments used to determine whether the programme had a positive educational effect. This paper reports on selected elements of the practices measurement. Structured interviews, observations and statistical analyses assessed three variables - container hygiene, container storage and hand hygiene. Results indicated insignificant improvements in practices. This was supported by insignificant improvements in the microbiological water quality, that was still above health-safety limits. This implied that short-term “quick fix” HHA&E programmes would tend to be ineffective. Results also suggested that some negative water-hygiene habits may readily change (container hygiene and storage), while behaviour of a more personal nature, such as hand-washing, was not easily changed.
The impact of the introduction of treated water on aspects of community health in a rural community in Kwazulu-Natal, South Africa
Authors: Bailey I.W. , Archer L.
Published: May 2018

A project was designed by Umgeni Water (funded by the Water Research Commission of South Africa) to monitor the implementation of water reticulation in Vulindlela and evaluate the Water Supply Scheme from a community and environmental health perspective. The findings would hopefully contribute toward the development of criteria for Health Impact Assessment on Water Reticulation Projects. One objective of this study was to evaluate the usefulness of diarrhoeal disease as opposed to other health indicators for water-associated diseases. The innovative methodology followed in the study, a “stepped wedge design”, compared four discrete areas of water reticulation implementation in Vulindlela over a 15-month period. Five surveys, including a baseline and four follow-ups at each household, were carried out. Analysis (microbiological, chemical) was carried out of samples from the household drinking water and from the source of the water. Each survey included health questionnaires, the respondent being the head of the household in each case. Overall, there was no direct correlation proved between water quality and diarrhoea per se. However, there was a marked decrease in diarrhoea with the introduction of the new water supply. There was definite correlation between hygiene behaviours and diarrhoea. Diarrhoea would seem to be the health impact associated with water, of choice.
Sewage impact on shellfish microbial contamination
Authors: Pommepuy M. , Dumas F. , Caprais M.P. , Camus P. , Le Mennec C. , Parnaudeau S. , Haugarreau L. , Sarrette B. , Vilagines P. , Pothier P. , Kholi E. , Le Guyader F.
Published: May 2018

Coastal areas are frequently contaminated by microorganisms of human origin, due to high population density and low seawater renewal. To evaluate the impact of wastewater input on shellfish quality, a study was conducted in Brittany (France) over a period of 20 months. A hydrodynamic model was used to simulate wastewater impact on microbial water quality. To validate the model, wastewater from the three main sewage treatment plants and shellfish from three sites were sampled monthly. Bacterial indicators (E. coli), F-RNA phages were searched for by culture and noroviruses by RT-PCR and hybridisation. These microorganisms were detected in the three effluents and clams, with no marked seasonal variation. The microbial concentrations in the two oyster beds, distant from the effluent outfall, were low, and only three of the samples were positive for norovirus. For simulation, the winter wastewater inputs of E. coli and phages were calculated and an estimation for norovirus flux was made from the epidemic situation in the population. The microbial behaviour was included in the model by a decay-rate factor. Results from the model calculations were found to be very similar to E. coli and phage concentrations observed in shellfish. For noroviruses, the model indicated that shellfish distant from the wastewater input were under the detection limit of the RT-PCR method. This study demonstrated the use of modelisation to interpret norovirus contamination in various areas.
Giardia and Cryptosporidium in source waters of Sao Paulo State, Brazil
Authors: Hachich E.M. , Sato M.I.Z. , Galvani A.T. , Menegon J.R.N. , Mucci J.L.N.
Published: May 2018

Giardia lamblia and Cryptosporidium parvum are two protozoan intestinal parasites responsible for many drinking-water-related disease outbreaks in recent years. They are very resistant to conventional water treatment processes, can persist for long times in the environment and are, therefore, of great concern for public health. This work aimed to evaluate the presence of Giardia and Cryptosporidium in water sources from São Paulo State, Brazil, as part of the “Evaluation of Inland Waters from Sao Paulo State” project from CETESB. Over a period of 19 months, 278 water samples from 28 sites located in 10 watersheds were analysed. The immunofluorescence assay was used after concentration of the samples by the calcium carbonate flocculation technique. Thermotolerant (faecal) coliforms, faecal streptococci and Clostridium perfringens were also determined in order to verify the existence of correlation between these bacterial indicators and the protozoa. Giardia and Cryptosporidium were detected in 27% and 2.5% of the samples, respectively, a lower figure compared with the results reported by other authors, especially for Cryptosporidium. A Spearman rank correlation test demonstrated a significant correlation between Giardia and faecal indicator concentrations. According to the American Regulation of Monitoring (ICR), treated water from 16 of these 28 collection sites should also be analysed to evaluate whether the treatment process could remove the parasites. Some technical deficiencies of these methods still limit the utilisation of the monitoring results for public health decisions, but the data here reported will help to improve the quality of drinking water in Sao Paulo State.
Evaluating real-time PCR for the quantification of distinct pathogens and indicator organisms in environmental samples
Authors: Lebuhn M. , Effenberger M. , Garcés G. , Gronauer A. , Wilderer P.A.
Published: May 2018

We evaluated quantitative real-time PCR (qPCR) and RTqPCR (for RNA species) for their ability to quantify microorganisms and viruses in problematic environmental samples such as cattle manure, digester material, wastewater and soil. Important developments included a standard spiking approach which compensated for methodological bias and allowed sample-to-sample comparison and reliable quantification. Programme CeTe was developed to calculate endogenous concentrations of target organisms (nucleic acid copies) for each sample separately from the generated standard curves. The approach also permitted assessment of the detection limit of the complete method, including extraction. It varied from sample to sample, due to different extraction efficiencies and variable co-extraction of PCR inhibitors. False negative results were thereby avoided. By using this approach we were able to optimise a DNA extraction protocol from the different tested sample types. Protocols for the extraction of RNA species from environmental samples were also optimised. DNA was (almost) not degraded after lethal shock (autoclaving) in the sterile environment. In contrast, the parallel selective cultivation and qPCR results for various microbial parameters from an anaerobic digester chain suggested that DNA from decaying organisms was readily recycled in metabolically active environments. It may, therefore, be used to determine viable organisms in samples exhibiting substantial metabolic turnover. It is proposed that our standard spiking approach, including data evaluation by the program CeTe, should be considered in future standardisation and norms for the quantification of nucleic acid containing organisms in environmental and product samples.
Controlling corrosion in drinking water distribution systems: a grand challenge for the 21st century
Authors: Edwards M.
Published: May 2018

It is argued that the water distribution system will be a key public health battlefield of the 21st century. Corrosion in private plumbing is deserving of special attention, since the health and economic impacts are probably of equal or greater magnitude compared to public systems, and there has not been an advocate working on behalf of the consumer to solve these problems. To better serve society in this endeavour we will need educational programs, aggressive research to minimize the unsustainable costs of corrosion, and to consider our legacy to future generations when making decisions on materials use.
Control of corrosion and aggression in drinking water systems
Authors: Loewenthal R.E. , Morrison I. , Wentzel M.C.
Published: May 2018

Corrosion and/or aggression are common problems arising in pipelines transporting terrestrial waters. The kinetics and severity of such events depend on both the quality of the water being transported and the material properties of the pipeline. Irrespective of the nature of the problem, its solution (or at least its minimisation) is strongly linked to control of pH, calcium concentration and carbonate chemistry of the water (stabilisation). However, application of such chemistry to water treatment problems is complex and time consuming. Various numerical, graphical and computer techniques have been developed to address this, but these are either of insufficient accuracy, too time consuming or lacking in generality. In this paper algorithms are presented for solving a broad spectrum of problems related to control of mineral precipitation/aggression, pH and chemical dosing in water treatment. These have been incorporated into a computer software package, STASOFT, which offers the requisite framework for use in water treatment. Various stabilisation problems pertinent to water supply are addressed.
QMRA (quantitative microbial risk assessment) and HACCP (hazard analysis and critical control points) for management of pathogens in wastewater and sewage sludge treatment and reuse
Authors: Westrell T. , Schönning C. , Stenström T.A. , Ashbolt N.J.
Published: May 2018

Hazard Analysis and Critical Control Points (HACCP) was applied for identifying and controlling exposure to pathogenic microorganisms encountered during normal sludge and wastewater handling at a 12,500 m3/d treatment plant utilising tertiary wastewater treatment and mesophilic sludge digestion. The hazardous scenarios considered were human exposure during treatment, handling, soil application and crop consumption, and exposure via water at the wetland-area and recreational swimming. A quantitative microbial risk assessment (QMRA), including rotavirus, adenovirus, haemorrhagic E. coli, Salmonella, Giardia and Cryptosporidium, was performed in order to prioritise pathogen hazards for control purposes. Human exposures were treated as individual risks but also related to the endemic situation in the general population. The highest individual health risk from a single exposure was via aerosols for workers at the belt press for sludge dewatering (virus infection risk = 1). The largest impact on the community would arise if children ingested sludge at the unprotected storage site, although in the worst-case situation the largest number of infections would arise through vegetables fertilised with sludge and eaten raw (not allowed in Sweden). Acceptable risk for various hazardous scenarios, treatment and/or reuse strategies could be tested in the model.
Removal of detergents by activated petroleum coke from a clarified wastewater treated for reuse
Authors: Ramírez Zamora R.M. , Duran Pilotzi A. , Dominguez Mora R. , Durán Moreno A.
Published: May 2018

The removal of detergents from clarified wastewaters by activated petroleum coke (CAPA) was assessed. These substances, owing to their foamy properties, constitute a problem for ammonia removal by the air stripping process that could be installed in a wastewater treatment train to produce reclaimed water. CAPA was evaluated as a more economical alternative than a commercial activated carbon. Experimental work was divided in three stages: 1) production and characterisation of materials; 2) pretreatment of raw wastewater through the Fenton's reagent or coagulation-flocculation process with Al2(SO4)3; and 3) adsorption and bio-adsorption tests of clarified effluents. These tests were carried out in the laboratory in discontinuous and continuous reactors, the former by the “point-by-point” technique, with and without a previous fixing of bacteria, and the latter by the Rapid Small Scale Column Test. Detergents content, color, COD and UV254nm were measured in raw and treated wastewaters. Results show that the best pretreatment for the adsorption process was coagulation-flocculation rather than Fenton's method. Oxidation by this process decreased the adsorptive properties of detergents. Biomass fixed on the CAPA particles significantly increased the UV254nm and COD removal efficiencies (20% and 170% respectively). The breakthrough curves showed that CAPA could attain the expected detergents removal efficiency (66%) for the alum effluent.
Low salt petroleum produced water reuse: a farming alternative outside the food chain
Authors: Rambeau O. , de Lafond Morales R. , Baldoni P. , Gosselin J.P. , Baccou J.C.
Published: May 2018

Oil and gas production gives rise to water production depending on the state of maturation of the Field. This means large volumes of water available. Today, this water is partly re-injected into the reservoir. Totalfinaelf's sustainable contribution to preserve water resources is to propose an alternative utilization: the reuse of produced waters from petroleum activities, outside the food chain. The aim of the first part of this study is to demonstrate the feasibility of utilizing low-salt water (<20 g/l) cleaned of hydrocarbons, for agricultural or forest irrigation. Rudimentary technologies such as artificial wetlands were tested to remove hydrocarbon substances and preliminary tests were performed with cotton (Gossypium hirsutum) and hemp (Cannabis sativa). Among the species tested in real conditions (greenhouse), hemp was affected by saline water whereas the results obtained for cotton were representative of the average worldwide production. These results validate the reuse of low-salt produced water in climatic conditions with expected temperatures of up to 37°C in summer and 25°C in winter. Following these results, field pilots are planned. Further research is planned to focus, taking into account local needs and environmental and production constraints.
Grey water characterisation and its impact on the selection and operation of technologies for urban reuse
Authors: Jefferson B , Palmer A. , Jeffrey P. , Stuetz R. , Judd S.
Published: May 2018

Characterisation of grey water reveals a source water that is similar in organic strength to a low-medium strength municipal sewage influent but with physical and biodegradability characteristics similar to a tertiary treated effluent. The characteristics of the water suggest biological processes are the most suitable unit processes for treating grey water. The highly variable nature of the source requires that selected technologies must be inherently robust in their operation. One potential area of concern is the high COD/BOD ratio and nutrient deficiency in terms of both macro and micro nutrients which grey water exhibits potentially retard the efficacy of biological processes.
Struvite scale formation and control
Authors: Parsons S.A. , Doyle J.D.
Published: May 2018

Struvite scale formation is a major operational issue at both conventional and biological nutrient removal wastewater treatment plants. Factors affecting the formation of struvite scales were investigated including supersaturation, pH and pipe material and roughness. A range of control methods have been investigated including low fouling materials, pH control, inhibitor and chemical dosing. Control methods exist to reduce scale formation although each has its advantages and disadvantages.
A review of fouling of membrane bioreactors in sewage treatment
Authors: Judd S.
Published: May 2018

Fouling in membrane bioreactors (MBRs) represents one of the most significant barriers to their more widespread implementation for both municipal and industrial wastewater treatment. It exerts a limit on the membrane permeability, i.e. the flux through the membrane per unit transmembrane pressure, and thus the productivity of the process per unit membrane area installed. As with all membrane processes, extensive investigation of factors contributing to fouling in MBRs, and the subsequent identification of ameliorative measures that may be taken to control it, has taken place since the process was first commercialised 30 years ago. Key findings of pertinent research in this area and operational experience in full-scale plants are summarised, along with the primary facets of the MBR process itself. The most recent evidence suggests that permanent fouling, i.e. fouling not substantially removed by physical cleaning (backflushing), results mainly from certain dissolved or colloidal organic materials, and such adsoptive fouling takes place at even the lowest operational fluxes. Fouling by suspended solids, on the other hand, may be largely controlled by operation below the so-called “critical” flux, which may be increased by more vigorous aeration, and/or by periodic backflushing. It is concluded that more work is required on characterisation of species responsible for permanent fouling.
Methods for understanding organic fouling in MBRs
Authors: Jefferson B. , Brookes A. , Le Clech P. , Judd S.J.
Published: May 2018

The identification and quantification of foulants in membrane bioreactors present a major challenge due to their complexity resulting from biomass heterogeneity. Fouling is normally characterised with respect to the critical flux, this being conventionally viewed as being the flux below which a reduction in membrane permeability does not take place. However, recent studies have revealed that such fouling arises even at very low fluxes. Moreover, fouling rates can differ substantially between different experiments, trials and installations even when operated under apparently similar conditions of biomass and soluble organic carbon concentrations. The methods available for quantifying and analysing fouling are reviewed with specific reference to recent data on sub-critical flux behaviour. It is concluded that HPSEC analysis of extracted biomass fractions may provide the most valuable data towards the determination of differences in fouling propensity between different biomasses, as inferred in conventional flux step analysis.
Microbial community structure of membrane fouling film in an intermittently and continuously aerated submerged membrane bioreactor treating domestic wastewater
Authors: Lim B.-R. , Ahn K.-H. , Songprasert P. , Cho J.W. , Lee S.H.
Published: May 2018

There was an observable difference in microbial community structure between suspended microorganisms and membrane biofouling film in intermittently and continuously aerated SMBRs. The dominant quinone type of membrane biofouling film in an intermittently aerated SMBR was ubiquinone (UQs)-8, -10 followed by menaquinone (MKs)-8(H4) and -8(H2). But that of the continuously aerated SMBR was UQs-10, -8 followed by MKs-6 and -8(H4). The experimental results also showed that the conditions of an intermittently aerated SMBR may contribute to biofouling by Pseudomonas, Moraxella, Vibrio (quinone type UQ-8), Staphylococcus warneri (quinone type MK-7), Micrococcus sp. (quinone type MK-8(H2)) and Nocardia sp. (quinone type MK-8(H4)), but biofouling in a continuously aerated SMBR may be due to Paracoccus sp. (quinone type: UQ-10) and Flavobacterium species (quinone type: MK-6). The microbial diversities in the intermittently aerated SMBR were 10.9 and 9.4 for biofouling film and suspended microorganisms, respectively. For the continuously aerated SMBR, the results were 10.4 and 10.5 for biofouling film and suspended microorganisms, respectively.
Design of reverse osmosis (RO) water treatment networks subject to fouling
Authors: See H.J. , Wilson D.I. , Vassiliadis V.S. , Parks G.T.
Published: May 2018

Identifying the optimal design for an RO membrane network is not straightforward when significant fouling occurs. The most robust optimal network design will feature the minimal capital and operating costs over the anticipated lifetime of the plant, and is therefore strongly dependent on the fouling behaviour and associated mitigation. This study considers the case where the likely fouling behaviour is known and investigates how to incorporate this knowledge into the design and operation of a network. The optimisation task is complicated by the highly non-linear nature of the problem owing to membrane behaviour, fouling behaviour, network interactions and operating parameter constraints (pressures and flows). In this work, fouling is modelled as an exponential decay in membrane permeability. Three optimisation approaches are used to evaluate candidate networks: (i) laborious comparison of pre-selected individual network designs; (ii) deterministic gradient search methods, and (iii) a simulated-annealing-based hybrid stochastic-deterministic method. All of the approaches consider various configurations of a two-stage network with a maximum of three membrane units in each stage, represented in a superstructure model. The results from the approaches are compared and the most effective method for network design is discussed.
Quality assessment of an aquifer recharged with wastewater for its potential use as drinking source: “El Mezquital Valley” case
Authors: Jimenez B. , Chávez A.
Published: May 2018

Mexico City, with a population of 18 million, has been sending its wastewater for more than 100 years to the Tula Valley where it is used to irrigate 90,000 ha. Due to the large wastewater volume (60 m3/s) sent through unlined channels, combined with the use of very high irrigation rates, artificial recharge of the local aquifer has been occurring. This recharge is estimated in more than 25 m3/s. As a consequence, the water table has raised and several springs have appeared in the last decades with flows between 100 to 600 L/s. These springs and several wells are the water sources in the region. An evaluation of the Tula Valley aquifer quality was performed to analyze the use of such water as source of drinking water for Mexico City. The work is divided into 5 individual projects: (a) drinking water quality in the Tula Valley; (b) water availability in the Tula Valley; (c) wastewater treatment due to its use for irrigation, (d) use of membrane processes to treat groundwater; and (d) biota developed in the new surface water reservoirs. Results show that it is feasible to use this reclaimed water as drinking source.