bluuebunny/crossref_metadata_2025 huggingface dataset:
Modeling diffuse pollution with a distributed approach
Authors: León L.F. , Soulis E.D. , Kouwen N. , Farquhar G.J.
Published: May 2018

The transferability of parameters for non-point source pollution models to other watersheds, especially those in remote areas without enough data for calibration, is a major problem in diffuse pollution modeling. A water quality component was developed for WATFLOOD (a flood forecast hydrological model) to deal with sediment and nutrient transport. The model uses a distributed group response unit approach for water quantity and quality modeling. Runoff, sediment yield and soluble nutrient concentrations are calculated separately for each land cover class, weighted by area and then routed downstream. The distributed approach for the water quality model for diffuse pollution in agricultural watersheds is described in this paper. Integrating the model with data extracted using GIS technology (Geographical Information Systems) for a local watershed, the model is calibrated for the hydrologic response and validated for the water quality component. With the connection to GIS and the group response unit approach used in this paper, model portability increases substantially, which will improve non-point source modeling at the watershed scale level.
Optimal operation of a potable water distribution network
Authors: Biscos C. , Mulholland M. , Le Lann M.-V. , Brouckaert C.J. , Bailey R. , Roustan M.
Published: May 2018

This paper presents an approach to an optimal operation of a potable water distribution network. The main control objective defined during the preliminary steps was to maximise the use of low-cost power, maintaining at the same time minimum emergency levels in all reservoirs. The combination of dynamic elements (e.g. reservoirs) and discrete elements (pumps, valves, routing) makes this a challenging predictive control and constrained optimisation problem, which is being solved by MINLP (Mixed Integer Non-linear Programming). Initial experimental results show the performance of this algorithm and its ability to control the water distribution process.
Effect of ozone injection location on filter performance in direct filtration
Authors: Yüksel E. , Akgiray Ö , Saatçi A.M. , Sarikaya H.Z. , Koyuncu I.
Published: May 2018

Two identical pilot scale sand filters were operated in parallel to study the effects of preozonation in direct filtration. No coagulants were used. The influent of one filter was ozonated, whereas the influent to the second filter was aerated. Significantly improved reduction in turbidity, particle count, and iron was observed with the filter receiving preozonated water. The head loss development rate was increased as a result of using ozone. In a second set of experiments, the effects of ozone injection point on filter performance were investigated. Two identical filters both receiving preozonated water were operated. With one of the filters, the raw water was ozonated immediately before it entered the filter. The entrance of the preozonated water to the other filter was delayed by using a detention tank between the ozone contact chamber and the filter. In addition to effluent turbidity and particle count values, zeta potentials of the waters entering the two filters were measured. Head loss development at several locations within each filter bed was also observed and recorded. Slightly better effluent quality (turbidity and particle count) was observed with the filter receiving preozonated water without delay. It was observed that the zeta potential of the prezonated water became more negative with increasing delay time.
Quantitative comparison of forests and other areas with dry weather input loading in the Lake Biwa catchment area
Authors: Fujii S. , Tanaka H. , Somiya I.
Published: May 2018

For the evaluation of pollutants loading to Lake Biwa, comprehensive river surveys on river mouths and forest sites were conducted 9 times from 1996 to 1999, on 25–40 main rivers in the Lake Biwa watershed. The main results obtained are as follows. (1) River water quality reflects regional characteristics of their catchment areas, and the concentration difference among rivers ranged between 2–3 fold. (2) Concentration variation shows different patterns with time and location depending on water quality indices used. (3) Indices related to organic matter and nutrients have lower correlation between forests and river mouths, but those related to ionic species showed strong correlation. (4) Flux comparison of forest and river mouth sites suggests that pollutants from catchment areas are conveyed to the lake not only through rivers but also underground. (5) In dry weather conditions, forests contribute 30% to the whole pollutants (TN, TP, and TCODMn) loading, and the remainder is derived mainly from paddy fields and residential/commercial zones. (6) Unit loading factors from forests are estimated as 640, 57 and 1200 kg/km2/y, respectively for TN, TP and TCODMn, while those from other areas are estimated as 2,500, 208 and 4,200 kg/km2/y.
Influence of varying reacting conditions in the degradation of azo dye using immobilized TiO2 photocatalyst
Authors: Aris A. , Md Din M.F. , Salim M.R. , Yunus S. , Abu Bakar W.A.
Published: May 2018

In Malaysia, most colored wastewater from dyeing factories is discharged to the environment causing serious problems. In this paper the influence of several reacting conditions, i.e. H2O2, pH, Ultraviolet (UV) intensity and dye concentration, on the performance of the immobilized system is discussed. The pH of the solution was varied from 3 to 11 while H2O2 concentration tested was from 10−4 M to 5×10−2 M. UV was tested at 365 nm and 254 nm, while dye concentration ranged from 2.5×10-4 M to 10-3 M. The influence of the reacting conditions was assessed based on absorbance. Using an OG concentration of 10−3 M, the degradation increases from 17.8% to 49.7%. Optimum concentration of H2O2 was found to be 5×10−3 M for degradation. Increasing the intensity of the UV light via shorter light wavelength also improves the performance of the system. Increasing the concentration of the dye reduces the overall performance of the system. Using the dye concentration of 2.5×10−4 M (H2O2 = 10−2 M, λ = 254 nm, pH = 11), gives a degradation of 93.2%. At dye concentration of 10−3 M, the performance was reduced to 53.1%.
Heavy metals extraction from anaerobically digested sludge
Authors: Marchioretto M.M. , Bruning H. , Loan N.T.P. , Rulkens W.H.
Published: May 2018

This paper reports on the chemical extraction efficiency in the removal of heavy metals from sludge from an activated-sludge system, which receives as influent both industrial and municipal wastewater. Utilizing a series of chemical extractants in a sequential order comprised the first phase of the research, called sequential chemical extraction (SCE). The work started with the well-known Tessier method followed by Veeken and by Sims and Kline SCE schemes. Afterwards, modified versions of Tessier and Veeken schemes were applied. The second phase, named chemical extraction using pH progressive changes, concerns an alternative to the extraction process. Four acids were tested: nitric, hydrochloric, oxalic and citric and the pH values as well as the time were varied. Some conclusions reveal that although modifying Tessier and Veeken schemes provides more consistent results, SCE is still an imperfect method regarding specificity and selectivity. Besides, it is not advisable to apply one SCE scheme developed for one specific situation to another one, once the accurateness of the method depends on several factors such as sort of material and chemicals, contact time, temperature, etc. The extraction efficiency increases using nitric or hydrochloric acids at low pH values, promoting high extraction efficiency level.
Anaerobic digestion of olive oil mill effluents together with swine manure in UASB reactors
Authors: Angelidaki I. , Ahring B.K. , Deng H. , Schmidt J.E.
Published: May 2018

Combined anaerobic digestion of olive oil mill effluent (OME) with swine manure, was investigated. In batch experiments was shown that for anaerobic degradation of OME alone nitrogen addition was needed. A COD:N ratio in the range of 65:1 to 126:1 was necessary for the optimal degradation process. Furthermore, it was found that methane productions rates during digestion of either swine manure alone or OME alone were much lower than the rates achieved when OME and manure were digested together. Admixing OME with manure at a concentration of 5 to 10% OME resulted in the highest methane production rates. Using upflow anaerobic sludge blanket (UASB) reactors, it was shown that codigestion of OME with swine manure (up to 50% OME) was successful with a COD reduction up to 75%. The process was adapted for degradation of OME with stepwise increase of the OME load to the UASB reactor. The results showed that the high content of ammonia in swine manure, together with content of other nutrients, make it possible to degrade OME without addition of external alkalinity and without addition of external nitrogen source. Anaerobic treatment of OME in UASB reactors resulted in reduction of simple phenolic compounds such as mequinol, phenyl ethyl alcohol and ethyl methyl phenol. After anaerobic treatment the concentration of these compounds was reduced between 75 and 100%. However, the concentration of some degradation products such as methyl phenol and ethyl phenol were detected in significantly higher concentrations after treatment, indicating that the process has to be further optimised to achieve satisfactory removal of all xenobiotic compounds.
Sludge utilisation in agriculture: possibilities and prospects in Greece
Authors: Andreadakis A.D. , Mamais D. , Gavalaki E. , Kampylafka S.
Published: May 2018

The paper presents the prospects for agricultural utilisation of the sludge produced from wastewater treatment plants in Greece and more specifically focuses on a critical review of the legislatory framework, determination of the quantitative and qualitative characteristics of the produced sludges, examination of possible sludge treatment methods and evaluation of the possibilities and prospects of sludge utilisation on the basis of the above considerations.

Landfilling is practically the only route to sludge disposal in Greece. However, in view of the anticipated future restrictions for landfilling within the European Union, this method is clearly a short-term solution and alternative options, including agricultural reuse, must be implemented. The results of a recent survey are presented and discussed in relation to this need.
Effects of substrates composed of biosolids on the production of Eucalyptus viminalis, Schinus terebinthifolius and Mimosa scabrella seedlings and on the nutritional status of Schinus terebinthifolius seedlings
Authors: Bonnet B.R.P. , Wisniewski C. , Reissmann C.B. , Nogueira A.C. , Andreoli C.V. , Barbieri S.J.
Published: May 2018

Six substrates made up with heated and composted anaerobic biosolid were tested for the production of Eucalyptus viminalis, Schinus terebinthifolius and Mimosa scabrella forest seedlings in a nursery in Southern Brazil. The produced seedlings were statistically evaluated in relation to height, stem diameter, height/stem diameter ratio, aerial and root dry biomass, survival, and also for nutritional status on S. terebinthifolius seedlings. As a function of their high pH, heated biosolids turned out to be viable only in low composition percentages. Composted biosolids turned out to be sufficiently suitable in percentages between 30% and 60% of the substratum - whose Mn and Zn concentrations relate the nutrient contents in the seedlings Ðwith use viability up to 100% in substratum composition.
Co-digestion of energy crops and industrial confectionery by-products with cow manure: batch-scale and farm-scale evaluation
Authors: Kaparaju P. , Luostarinen S. , Kalmari E. , Kalmari J. , Rintala J.
Published: May 2018

The possible co-digestion of energy crops and industrial confectionery by-products with cow manure was evaluated firstly, through long-term batch experiments and secondly, in a farm-scale digester. In batch assays, digestion with mesophilically digested cow manure as inoculum resulted in specific methane yields (m3 kg−1 VSadded waste) of 0.35 for grass hay (particle size <1.0 cm); 0.26 for oats (0.5 cm) and 0.21 for clover (2.0 cm) harvested at vegetative stage and 0.14 (2.0 cm) for clover harvested at flowering stage. Specific methane yields (m3 kg−1 VSadded waste) for confectionery by-products were 0.37 for chocolate, 0.39 for black candy and 0.32 for confectionery raw material. Out the three particle sizes (2.0, 1.0 and 0.5 cm) tested, particle size of 1.0 cm was found ideal for digestion of grass hay and clover while, particle size reduction did not influence methane production from oats. Stage of the crop influenced the methane yields, with clover harvested at vegetative stage yielding 33% higher methane than when harvested at flowering stage. An approximate 60% enhancement in methane yield was noticed with the co-digestion of industrial confectionery wastes with cow manure in a full-scale farm digester.
Low temperature conversion of sludge and shavings from leather industry
Authors: Silveira I.C.T. , Rosa D. , Monteggia L.O. , Romeiro G.A. , Bayer E. , Kutubuddin M.
Published: May 2018

Brazil has one of the largest herds of cattle in the world, with more than 170 million heads. Over 400 farms have exported more than 2,875 ton (in 1997) of leather to Europe. The wet blue tanning process uses chemicals such as chromium compounds and produces liquid wastes that must be treated by physico-chemical and biological systems. About 15,000 ton per month of dewatering sludge with 24% solids content is disposed of into landfills. During the process, pre-tanned skins (wet blue leather) are shaved to the desired thickness and the shavings, like sludge, are among the wastes that must have special attention. The organic content and chromium concentration are high. About 12% of the leather production from cattle hides are shavings, and its chromium concentration ranges from 3.5 to 5.5% of dry matter. The Environmentally friendly leather project, a co-operation between Brazilian and German tanneries, universities and technical schools, is looking for process optimisation, waste minimisation and adequate treatment for solid and liquid wastes from the leather industry. This work presents results of Low Temperature Conversion of chrome-containing sludge and shavings in a laboratory batch reactor, offering a solution for these hazardous wastes, recovering the energy content and transforming metals in insoluble sulphides.
Wastewater sludge as a resource: sludge disposal strategies and corresponding treatment technologies aimed at sustainable handling of wastewater sludge
Authors: Ødegaard H. , Paulsrud B. , Karlsson I.
Published: May 2018

The paper discusses different strategies for the disposal of wastewater sludge, particularly the “use on land” strategy and the “productification” strategy. In the “use on land” strategy the new regulations in Europe call for stabilization as well as disinfection of sludge to be used on land. The paper discusses the design and operation experiences with stabilization/disinfection methods in Norway where such treatment has been compulsory since 1995. In the “productification” strategy it is differentiated between the production of “bio-soils” and production of specific products (energy, nutrients, coagulants etc) and the “marketability” of these products is evaluated. An example of a sludge treatment concept aimed at recycling - the KREPRO process - is presented.
Anaerobic digestion for sustainable development: a natural approach
Authors: Gijzen H.J.
Published: May 2018

After the discovery of methane gas by Alessandro Volta in 1776, it took about 100 years before anaerobic processes for the treatment of wastewater and sludges were introduced. The development of high rate anaerobic digesters for the treatment of sewage and industrial wastewater took until the nineteen-seventies and for solid waste even till the nineteen-eighties. All digesters have in common that they apply natural anaerobic consortia of microorganisms for degradation and transformation processes. In view of this, it could be rewarding to evaluate the efficiency of natural ecosystems for their possible application. Examples of high rate anaerobic natural systems include the forestomach of ruminants and the hindgut of certain insects, such as termites and cockroaches. These “natural reactors” exhibit volumetric methane production rates as high as 35 l/l.d. The development of anaerobic reactors based on such natural anaerobic systems could produce eco-technologies for the effective management of a wide variety of solid wastes and industrial wastewater. Important limitations of anaerobic treatment of domestic sewage relate to the absence of nutrient and pathogen removal. A combination of anaerobic pre-treatment followed by photosynthetic post-treatment is proposed for the effective recovery of energy and nutrients from sewage. This eco-technology approach is based on the recognition that the main nutrient assimilating capacity is housed in photosynthetic plants. The proposed anaerobic-photosynthetic process is energy efficient, cost effective and applicable under a wide variety of rural and urban conditions. In conclusion: a natural systems approach towards waste management could generate affordable eco-technologies for effective treatment and resource recovery.
Adaptation of the methanogenic granules to denitrification in anaerobic-anoxic USSB reactor
Authors: Jenicek P. , Zabranska J. , Dohanyos M.
Published: May 2018

Continuous laboratory experiments have confirmed that the construction of the USSB reactor was suitable for the combination of several biological wastewater treatment processes and that both anaerobic and denitrifying anoxic granules could be cultivated inside a compact reactor. The anoxic granules were transformed from the anaerobic granules after the shift from anaerobic to anoxic conditions in the upper compartments of the USSB reactor. The denitrification in such a system can be very intensive and efficient because of the high concentration of the sludge in anoxic compartments, and the high activity of the sludge due to a high and stable temperature. The denitrification rate of 62 mg N/l.h (at 35°C) was achieved in spite of COD-limited conditions in the anoxic compartment of the USSB reactor. Maximum specific activity of anoxic granules 47 mg N/g VSS.h (at 35°C, with glucose as substrate) was found in batch tests. The anoxic granules originating from the anaerobic granules have still demonstrated a significant methanogenic activity comparable with the anaerobic granules.
Use of satellite image analysis to track wetland loss on the Murrumbidgee River floodplain in arid Australia, 1975-1998
Authors: Kingsford R.T. , Thomas R.F.
Published: May 2018

Demonstrating the extent of wetland loss and its causes are essential for policy makers and managers. We used Landsat satellite imagery to show major wetland loss in the Lower Murrumbidgee floodplain on the Murrumbidgee River in arid Australia. Stratification of the floodplain according to hydrology, use of imagery from the same time of year and the separation of developed areas, using ancillary information were essential. There was considerable loss of floodplain area over a 23 year period (1975-1998), mainly in the Nimmie-Caira stratum (59% loss), as wetland areas were replaced by irrigation bays. There was also a significant increase in fragmentation. For floodplain areas distant from the river, flooding patterns were more difficult to identify because of infrequent flooding and primary reliance on rainfall. Landsat imagery provided a powerful tool for demonstrating long-term changes in wetland area, even in highly variable environments. Such information can demonstrate the ecological costs of water resource development on floodplains, forming a basis for policy and management of rivers.
Managing for river health - integrating watercourse management, environmental water requirements and community participation
Authors: Scholz G. , VanLaarhoven J. , Phipps L. , Favier D. , Rixon S.
Published: May 2018

The Mid North Rivers Management Planning Project (MNRMPP) of the Environment Protection Agency, Department for Environment and Heritage began as a response to community concerns regarding watercourse related issues in the Mid North of South Australia. In response to these concerns the MNRMPP project team developed rapid, cost effective methods to collect and assess data, establish collaborative partnerships with stakeholder organisations, ensure community involvement, and initiate mechanisms to sustain local involvement past the life of the project. Environmental water requirements were identified, along with key watercourse management issues; the integration of these two components of the study enabled more informed decision making regarding watercourse management within the study area. The integration of these components and the involvement of the community and stakeholders through all components of the project has resulted in a sense of ownership and an increase in awareness of watercourse related issues. This has increased the prospect of individuals and organisations implementing the management options and priorities identified within the plan, and has promoted the long term involvement of these groups in better watercourse management.
Barmah-Millewa forest environmental water allocation
Authors: Stewart G. , Harper B.
Published: May 2018

The formal allocation of water for the environment is a developing area of river management both scientifically and in terms of community participation. This case study, illustrating the recent use of the Barmah-Millewa Forest Environmental Water Allocation (EWA), provides a practical demonstration of community participation in environmental water management, the application of hydrological and biological “triggers” and a positive, demonstrable biological outcome from an environmental water allocation. The Barmah-Millewa Forest covers an area of 70,000 ha across the floodplain of the Murray River, upstream of the town of Echuca. About half the forest is in NSW (Millewa) and half is in Victoria (Barmah). The Barmah Forest is a Wetland of International Importance listed under the Convention on Wetlands - Ramsar Convention. The forest is the largest river redgum forest in the world. The natural flooding cycle associated with the forest has been significantly altered by regulation of the Murray River - impacting upon the overall health of the forest ecosystem. Recognising this, the Murray Darling Basin Commission developed a water management strategy for the forest to enhance forest, fish and wildlife values. To implement this strategy, between 1990 and 1993 reports were completed and community consultation took place. In 1993 the Murray Darling Basin Ministerial Council approved allocation of 100 Gigalitres of water per year, provided in equal shares by NSW and Victoria, to meet the needs of the forest ecosystem and in 1994 the Barmah-Millewa Forum was established under the Murray-Darling Basin Agreement. The vision for the Forum is to maintain and, where possible, improve the ecological and productive sustainability of the Barmah-Millewa Forest and to establish a planning and operational framework to better meet the flooding and drying requirements of the riparian forests and wetlands. Between October 2000 and January 2001 the Barmah-Millewa Forest Environmental Water Allocation was used for the second time. A total of 341 GL was released as an EWA. This amount represented only 8% of the total flows downstream of Yarrawonga Weir from September 2000 and January 2001. The strategic use of the relatively small amount of water enabled flooding to be maintained and ensured significant breeding success for water birds and other biota in the Forest.
Algal treatment of pulp and paper industry wastewaters in SBR systems
Authors: Tarlan E. , Yetis Ü. , Dilek F.B.
Published: May 2018

Highly colored and highly polluted pulp and paper industry wastewaters are proposed to be treated by using algae in sequential batch reactors (SBR). Results of batch studies revealed that up to 74% COD; 74% color removal could be attained in about 40 days of incubation. From the preliminary SBR experiments, filling period was found to be a critical step affecting the overall efficiency when mixing and aeration is applied during filling. Therefore, 5 different filling periods (4, 6, 8, 10 and 12 days) were studied with a total SBR cycle of 15 days. For all filling periods; COD, color and AOX removal efficiencies increased with increasing filling time. Maximum removal efficiencies achieved were 60 to 85% for COD, 42 to 75% for color and 82 to 93% for AOX for the filling periods of 4 to 12 days. For 8 days or longer filling periods, no additional reaction time was required. Results showed that, organics in the wastewater were both chlorinated and non-chlorinated; algae removed these mainly by metabolism; and chlorine cleavage from chlorinated organic molecules was more rapid than the degradation of non-chlorinated and colored organics. Adsorbed lignin on algal biomass was found to be varying between 10-20% depending on filling period applied.
Dairy wastewater treatment in a moving bed biofilm reactor
Authors: Andreottola G. , Foladori P. , Ragazzi M. , Villa R.
Published: May 2018

Dairy raw wastewater is characterised by high concentrations and fluctuations of organic matter and nutrient loads related to the discontinuity in the cheese production cycle and machinery washing. The applicability of a Moving Bed Biofilm Reactor (MBBR) filled with FLOCOR-RMP® plastic media to the treatment of dairy wastewater was evaluated in a pilot-plant. COD fractionation of influent wastewater, MBBR performance on COD and nutrient removal were investigated. A removal efficiency of total COD over 80% was obtained with an applied load up to 52.7 gCOD m−2 d−1 (corresponding to 5 kgCOD m−3d−1). The COD removal kinetics for the MBBR system was assessed. The order of the kinetics resulted very close to half-order in the case of a biofilm partially penetrated by the substrate. The nitrogen removal efficiency varied widely between 13.3 and 96.2% due to the bacterial synthesis requirement. The application of a MBBR system to dairy wastewater treatment may be appropriate when upgrading overloaded activated sludge plants or in order to minimise reactor volumes in a pre-treatment.
Competitive growth kinetics of Sphaerotilus natans and Acinetobacter anitratus
Authors: Contreras E.M. , Giannuzzi L. , Zaritzky N.E.
Published: May 2018

Growth kinetics of Sphaerotilus natans and Acinetobacter anitratus (strain E932) in pure and mixed cultures were analysed. In order to determine mixed cultures biomass composition, a quantitative image analysis technique was developed. Pure culture studies showed that for dilution rates less than 0.188 h−1, the filamentous micro-organism will predominate leading to bulking phenomena. By using the developed technique to determine biomass composition, mixed culture experiments showed that changes in the dilution rate modify the microbial composition of the biomass determining which micro-organisms predominate. The stated equations that predict the predominance of S. natans at low dilution rates agree satisfactorily with the obtained results.
Ciliated protozoa and organic load at low temperatures in an aerated biofilter
Authors: García-Santana C. , González-Martínez S.
Published: May 2018

Ciliated protozoa have been widely used as water quality indicators because their main morphological characteristics are relatively simple to identify microscopically. The species and individual numbers in wastewater treatment systems are a consequence of the operational and environmental conditions of the process. The main objective of this research was to relate the effluent quality of a pilot aerated biofilter with the presence and relative abundance of ciliated protozoa when operated under different organic loading rates. The experimental work was done in a pilot aerated biofilter using 12 mm volcanic porous stones as filtering media and it was fed with municipal wastewater adjusting the experiments to 3 organic loading rates (3, 7, and 9 gCOD/m2·d). Temperature in the filter varied from 11 to 14°C during the experimental work. COD and BOD removal rates do not change significantly with the different organic loads. Nitrification improves inversely to the organic load and it does not show dependence on the slight temperature changes observed. Eighteen species were identified as typical residents in wastewater systems. Free swimming species prefer higher organic loads. Crawling and attached species did not show significant changes with the organic load. According to the saprobity index of Pantle and Buck, the system, independently of the organic load, presented typical α-mesosaprobe level.
Biofilm development in down flow anaerobic fluidised bed reactors under transient conditions
Authors: Tessele F. , Englert G. , Monteggia L.O.
Published: May 2018

Biofilm development onto polypropylene particles (<4 mm) was studied in a laboratory-scale down flow anaerobic fluidised bed reactor. The reactor was fed with a synthetic solution containing sucrose and nutrients, and operated at 35°C during 65 days at 44% bed expansion rate and 36 h HRT. Scanning electron microscopy (SEM) monitored the biofilm development. Initial adhesion occurred within the first 6 hours and after day 44 biofilm structure was complete. The presence of attached cells morphologically similar to Methanotrix bacilli and Methanosarcina sp. was observed by Scanning Electron Microscopy (SEM). The biofilm and the carrier surface roughness were measured by atomic force microscopy (AFM) and yielded 9.1 and 75 nm respectively. Results also showed good correlation between the SEM characterisation and the conventional anaerobic reactor parameters.
Population dynamics in an aerobic submerged fixed bed reactor (ASFBR) process
Authors: Lorda-de-los-Ríos I. , Bécares-Mantecón E. , Tejero-Monzón I.
Published: May 2018

In this study, an aerobic submerged fixed bed reactor's (ASFBR) population dynamics has been studied in order to know its behavior in different conditions of organic load and oxygen concentration. The reactor was fed with synthetic wastewater. Tested variables and applied values were: 1) Variations in organic load (OL): 16–65 g COD/m2/d. 2) Variations in influent's COD concentration: 40–400 g COD/m3. 3) Variations in specific air flow (SAF): 15–127 m3air/kgCOD. Biofilm samples were taken at the top of the reactor. This study showed important variations in the composition and abundance of the microfauna depending on the experimental conditions. Variations in influent concentration had no significant effect on the abundance of the studied groups. However, differences depending on organic load and aeration conditions were observed. Organic load influenced every group studied but with different results. Sessile cilliates, metazoa and flagellates were abundant in low load, while crawling ones were in high load. Aeration intensity influenced most of the groups except Peranema and Vorticella spp. Despite obtaining good yields, not many protozoa, typical of biofilms under conventional processes, were found. Thus, a great variety of microorganisms, such as many classes of sessile and crawling cilliates, were not found. Important nitrifying activity was obtained at 20 cm depth in a bed. From this point, the heterotrophic and nitrifying populations exist but are inactive.
The characteristics of the biofilm fixed inside porous medium by sequencing batch reactor
Authors: Hoshi K. , Deguchi H.
Published: May 2018

The fixed biomass inside porous medium has two layers where biomass yield constants are different from each other when it is cultivated in the chemostat reactor. The biomass fixed inside porous medium is tested to see whether the operation type affected the structure of it. Two kinds of operation method of the reactor were used for the biofilm cultivation. One is the batch reactor. Another is the chemostat reactor. From the kinetic test, it is found that the biofilm fixed in the batch reactor does not have two layers that were observed in the biofilm from the chemostat reactor. Within the experimental conditions for type-1, the result of kinetic tests show homogeneous biofilm characteristics. It can be concluded that the reactor type (batch type or chemostat type) affects the structure of biomass fixed inside porous medium.
The development and use of real-time PCR for the quantification of nitrifiers in activated sludge
Authors: Hall S.J. , Hugenholtz P. , Siyambalapitiya N. , Keller J. , Blackall L.L.
Published: May 2018

Chemical analytical data has long been used to monitor the performance of activated sludge plants even though the process relies on the performance of microorganisms. It is now evident that a rapid and reliable quantitative method is required, to be able to monitor the organisms responsible for nutrient transformation and their activities, allowing avenues for more efficient nutrient removal. The development of real-time or quantitative polymerase chain reaction (PCR) also known as TaqMan® or 5′-nuclease assay has allowed the rapid, quantitative analysis of DNA templates, eliminating some of the variability traditionally associated with other quantitative techniques. In this study analysis of Nitrospira spp., one of the key organisms in nitrite oxidation in wastewater treatment, was used to validate real-time PCR for the their quantification in activated sludge. A probe and primer set, targeting the 16S rRNA gene of Nitrospira spp. was designed according to the constraints of the TaqMan® specifications. Samples used to evaluate the method included DNA from the sludge from full-scale wastewater treatment plants and laboratory scale systems. The reproducibility, quantitative efficiency and specificity were assessed in the evaluation. It was concluded that the method is sensitive and reproducible but has some constraints on the quantitative efficiency. A survey of full-scale systems for Nitrospira spp. was carried out and the results are presented here.
PHA storage from several substrates by different morphological types in an anoxic/aerobic SBR
Authors: Dionisi D. , Levantesi C. , Renzi V. , Tandoi V. , Majone M.
Published: May 2018

An activated sludge was cultivated on a mixture of several soluble substrates (acetate, ethanol, glucose, glutamic acid, peptone, Tween 80, starch, yeast extract) in an anoxic/aerobic SBR. Highly dynamic conditions in the SBR (feast famine regime) caused fast removal of most COD in the anoxic phase (in particular acetate, ethanol, glutamic acid and glucose were totally removed) and relevant contribution of storage. In spite of that, filament abundance was always high, as is typical of bulking sludges. Filaments which developed in the reactor were characterized on a morphological basis and on the basis of their ability to grow and to store polyhydroxyalkanoates (PHAs). Three main filaments prevailed in the biocenosis, whose relative abundance was varyng with time: Nostocoida limicola II, (two different morphological types), Haliscomenobacter hydrossis and an unidentified one. It was found that maximum growth rate was higher for flocformers than for filaments on each of the tested substrates. Epifluorescence showed that storage ability was more widespread among flocformers than in the filaments. Only one type of Nostocoida limicola II was able to store PHAs. The obtained data show that aerobic growth on the little residual fraction of COD from the anoxic phase was enough to support high abundance of filamentous microorganisms.
Study of filamentous bacteria by image analysis and relation with settleability
Authors: da Motta M. , Pons M.N. , Roche N.
Published: May 2018

An automated procedure for the characterisation by image analysis of the morphology of activated sludge has been used to monitor the biomass in a pilot wastewater treatment plant during two runs inoculated with a different sludge and operated at two different temperatures. The bulking events were easily detected by image analysis. Correlations were found between settleability properties (Sludge Volume Index and settling velocity) and the morphological parameters (filament total length, filament number and floc size).
The affection of flow pattern on kinetic characteristic of the biomass fixed inside porous medium
Authors: Matsui Y. , Deguchi H.
Published: May 2018

The characteristics of the biomass fixed inside porous medium (sponge cube) have been investigated to see whether it can be recognized as biofilm. The acrylic cube is used as control medium. Three types of flow pattern of bulk water are used in the test to examine its effect on substrate transportation. From the kinetic test, it is found that the biomass fixed inside the sponge cube has biofilm characteristics. For conditions where the diffusion phenomenon is dominant, two layers whose yield constant are different to each other are confirmed from stoichiometric study. When the sponge cube is in the counter flow, it was found that the whole biomass fixed inside the medium works at the same time. It is considered that a certain amount of water is flowing through the medium when the sponge cube is exposed to counter flow. When the water is totally flowing through the sponge cube during the kinetic test by using type-3 reactor, a Michaelis-Menten type equation can represent the results of the kinetic test.
Control of the growth of Microthrix parvicella by using an aerobic selector – results of pilot and full scale plant operation
Authors: Lebek M. , Rosenwinkel K.-H.
Published: May 2018

A two-stage wastewater treatment plant experiences in bulking sludge problems in winter, correlating with Microthix parvicella abundance. Pilot and full-scale studies of the use of an aerobic selector to control M. parvicella had little success, probably resulting from long chain fatty acid retention in foam at the tank surface. Initial pilot studies with reduced foam retention showed better results.
The effect of C/N ratio on ammonia oxidising bacteria community structure in a laboratory nitrification-denitrification reactor
Authors: Ballinger S.J. , Head I.M. , Curtis T.P. , Godley A.R.
Published: May 2018

A laboratory scale reactor operated as a single sludge, denitrification-nitrification bioreactor (DNB), was fed a synthetic wastewater. The effect of the C/N ratio of the influent on the structure of ?-proteobacterial autotrophic ammonia-oxidizing bacterial (AOB) communities was determined by DGGE analysis of 16S rRNA gene fragments amplified using a range of AOB-selective primers. Fluorescence in situ hybridisation (FISH) was used to determine quantitative changes in the AOB communities. When operated at a C/N ratio of 2 the DNB was effective in nitrogen removal and nitrification was measured at approximately 1.0 mg NH4+-N/g dry wt/h. Altering the C/N ratio to 5 resulted in a 50% reduction in nitrification rates. Nitrification was restored to its original level when the C/N ratio was returned to 2. AOB were detected by DGGE analysis of samples from the DNB under all operating conditions but the changes in C/N ratio and nitrification rates were accompanied by changes in the community structure of the AOB. However, quantitative FISH analysis indicated that β-proteobacterial AOB were only present in high numbers (ca. 108 cells/ml) under the original operating conditions with a C/N ratio of 2. β-Proteobacterial AOB could not be detected by FISH when the C/N ratio was 5. When nitrification activity was restored by returning the C/N ratio to 2, β-proteobacterial AOB were still not detected and it is likely that either β-proteobacterial AOB were not responsible for ammonia oxidation or that β-proteobacterial AOB that did not contain the target sites for the range of 4 AOB selective probes used, were present in the reactor.
In-line fast OUR (oxygen uptake rate) measurements for monitoring and control of WWTP
Authors: Baeza J.A. , Gabriel D. , Lafuente J.
Published: May 2018

This paper shows how using in-reactor on-line monitoring of OUR in the aerobic reactors of an A2/O (anaerobic, anoxic, oxic) nutrient removal system, the implemented control system is able to improve the nitrogen removal of the plant. The control system adapts the operation to different load conditions, without the need for additional information provided by other analysers. In particular, these OUR measurements and on-line information available in the distributed control system (temperature, biomass concentration and flows) are used for the estimation of the COD load in the influent, and automatically applied in the adaptation of the operational mode of the nutrient removal process. The estimation is realised using Artificial Neural Networks models trained with available data from the system. The operational changes consist in the modification of the total aerated volume in the pilot plant as a function of the load estimation. With the implemented control system based on COD load estimation, an increase in nitrogen removal of 10% was obtained with respect to a system working with fixed aeration volume, and using a suitable amount of energy in each case.
Simultaneous nitrification and denitrification in a single reactor using bio-electrochemical process
Authors: Watanabe T. , Hashimoto S. , Kuroda M.
Published: May 2018

Feasibility of a bio-electrochemical process for simultaneous nitrification and denitrification in a single reactor was experimentally investigated. The reactor consisted of anodic and cathodic electrodes, on which nitrifying and denitrifying biofilms, respectively, were fixed. Effects of the applied electric current and DO concentration in the bulk solution were examined. The TN removal could be achieved through the occurrence of nitrification and denitrification in anodic and cathodic biofilms, respectively. Both nitrification and denitrification rates increased with an increase in the applied electric current. Even at low DO concentration in the bulk solution, nitrification proceeded at a high rate by utilizing oxygen generated on the anode. Denitrification rate remained relatively high at high DO concentration due to supplying hydrogen gas to the inner side of the cathodic biofilm. The higher TN removal rate tended to be obtained at lower DO concentration and higher current density. From these results, it was concluded that the bio-electrochemical process was applicable to simultaneous nitrification and denitrification due to stable formation of aerobic and anoxic regions in the single reactor.
Low-cost failure sensor design and development for water pipeline distribution systems
Authors: Khan A. , Widdop P.D. , Day A.J. , Wood A.S. , Mounce S.R. , Machell J.
Published: May 2018

This paper describes the design and development of a new sensor which is low cost to manufacture and install and is reliable in operation with sufficient accuracy, resolution and repeatability for use in newly developed systems for pipeline monitoring and leakage detection. To provide an appropriate signal, the concept of a “failure” sensor is introduced, in which the output is not necessarily proportional to the input, but is unmistakably affected when an unusual event occurs. The design of this failure sensor is based on the water opacity which can be indicative of an unusual event in a water distribution network. The laboratory work and field trials necessary to design and prove out this type of failure sensor are described here. It is concluded that a low-cost failure sensor of this type has good potential for use in a comprehensive water monitoring and management system based on Artificial Neural Networks (ANN).
Disturbance detection and isolation in the activated sludge process
Authors: Yoo C.K. , Choi S.W. , Lee I.
Published: May 2018

This paper proposes a new fault detection and isolation (FDI) method. This method monitors the distribution of process data and detects changes in this distribution, which reflect changes in the corresponding operating condition. A modified dissimilarity index and a FDI technique are defined to quantitatively evaluate the difference between data sets. This technique considers the importance of each transformed variable in the multivariate system. The FDI technique is applied to a benchmark simulation and to data from a real wastewater treatment plant. Simulation results show that it immediately detects disturbances and automatically distinguishes between serious and minor anomalies for various types of fault. The method not only detects the disturbances, but also isolates the scale of the disturbance, facilitating the interpretation of the disturbance source. The proposed monitoring technique is found to be appropriate for analyzing the biological wastewater treatment process, which is characterized by a variety of fault and disturbance sources and non-stationary characteristics.
Adaptive multiscale principal components analysis for online monitoring of wastewater treatment
Authors: Lennox J. , Rosen C.
Published: May 2018

Fault detection and isolation (FDI) are important steps in the monitoring and supervision of industrial processes. Biological wastewater treatment (WWT) plants are difficult to model, and hence to monitor, because of the complexity of the biological reactions and because plant influent and disturbances are highly variable and/or unmeasured. Multivariate statistical models have been developed for a wide variety of situations over the past few decades, proving successful in many applications. In this paper we develop a new monitoring algorithm based on Principal Components Analysis (PCA). It can be seen equivalently as making Multiscale PCA (MSPCA) adaptive, or as a multiscale decomposition of adaptive PCA.

Adaptive Multiscale PCA (AdMSPCA) exploits the changing multivariate relationships between variables at different time-scales. Adaptation of scale PCA models over time permits them to follow the evolution of the process, inputs or disturbances. Performance of AdMSPCA and adaptive PCA on a real WWT data set is compared and contrasted. The most significant difference observed was the ability of AdMSPCA to adapt to a much wider range of changes. This was mainly due to the flexibility afforded by allowing each scale model to adapt whenever it did not signal an abnormal event at that scale. Relative detection speeds were examined only summarily, but seemed to depend on the characteristics of the faults/disturbances. The results of the algorithms were similar for sudden changes, but AdMSPCA appeared more sensitive to slower changes.
Assessing the environmental impact of WWTP expansion: odour nuisance and its minimization
Authors: Capodaglio A.G. , Conti F. , Fortina L. , Pelosi G. , Urbini G.
Published: May 2018

As part of the effort to provide proper wastewater disposal for the City of Milan, the expansion of the WWTP located in Peschiera Borromeo has been planned and is currently under completion. The plant, sized for a population of less than 300,000, will soon treat the wastes from the south-east areas of Milan for a total capacity of over 500,000 p.e. The paper describes the approach to find a satisfactory solution of an alleged odour problem that is slowing down the completion of the plant restructuring. This included a survey of the existing plant and analysis of its final design, identification of odour emission sources and their quantification, and the examination of different alternatives for odour abatement. These were carried out using air quality modelling techniques consisting of dynamic, continuous “puff” models capable of reproducing diffusion even at very low pollutant concentrations. Several intervention hypotheses were tested and compared with the few existing regulatory norms and guidelines for odour pollution. In all but the minimum and the no-action hypotheses, proposed actions would results in a drastic reduction of nuisance effects at the receptors. Under the strongest intervention hypothesis (the one adopted by the WWTP agency), odour impact would be virtually eliminated.