bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of lamp intensity and water transmittance on the UV disinfection of water
Authors: Sommer R. , Cabaj A. , Pribil W. , Haider T.
Published: May 2018

The efficiency of UV disinfection devices depends on flow, lamp intensity and water transmittance. In practice the flow is controlled by suitable methods, whereas the other two parameters, to date, have not been taken into consideration sufficiently. The surveillance of the function of UV disinfection plants is routinely based on a sensor placed on the irradiation chamber wall. This measures changes of UV irradiance without differentiating if the effect is caused by transmittance or lamp intensity so that two different conditions of disinfection may occur at the same sensor readings. We investigated the influence of transmittance vs intensity on disinfection at the same sensor readings in a specially designed laboratory flow through UV irradiation system with one single UV lamp as well as in commercially available UV disinfection plants with multiple UV lamps. All devices were equipped with a calibrated selective UV detector connected to a UV radiometer. Lamp intensity was decreased by diminishing the supply voltage. UV transmittance was reduced by pumping aqueous sodium thiosulphate solution into the water inflow. The disinfection capacity was determined by measuring the reduction equivalent doses (RED) using a standardised biodosimetric method. We showed that equal sensor readings, either achieved by reducing the lamp intensity or by lowering the UV transmittance of the water, resulted in different REDs in one-lamp systems. The diminishing of UV intensity caused a greater decrease of REDs than reducing the water transmittance. However, in the multiple-lamp systems tested, equal sensor readings yielded equal REDs.
Stormwater runoff from typical developed and developing South African urban developments: definitely not for swimming
Authors: Jagals P.
Published: May 2018

Public water in South Africa is protected from pollution from urban areas and industries through various forms of wastewater treatment and enforced by legislation and standards. However, hardly any standard or guideline exists for an acceptable quality for urban run-off such as stormwater. The microbiological quality of urban run-off from various large urban developments in the Free State Province, South Africa, has been investigated to establish the extent of faecal pollution. Sanitation of a low socio-economic urban residential development was generally limited, comprising mainly pit and bucket latrines. Sanitation of the other developments was typical of the larger more developed South African urban situation. It comprised well developed residential structures with full water-borne sewerage, fully serviced central business districts, developing residential areas with both waterborne sewerage and additional areas of informal settlement with limited facilities. Faecal coliforms (FC) and enterococci (FE) were used as generalised indicator organisms of faecal pollution together with sorbitol-fermenting bifidobacteria (SFB) and Streptococcus bovis (SB). Somatic (SC) and male specific coliphages (MSC) were used as indicators of organic and sewage pollution of the receiving water in the target areas. Samples were collected from perennial flow during the dry season and from stormwater run-off after thundershowers. Stormwater run-off from the large settlement with limited facilities as well as from the residential development with additional informal settlement reached FC counts of <6 logs/100mL, equivalent to many sewage effluents. Stormwater run-off from well developed urban structures reached FC of <4 logs/100mL, which exceeded safety margins in guidelines for recreational water quality. The results show that run-off from developing urban settlements, as well as developed urban structures, constitute a major source of pollution for a river catchment which is downstream used as a source of water for human consumption and recreation. The level of pollution dictates that stabilisation of urban surface run-off should be regarded as an equal priority to the enforced stabilisation of other wastewaters generated by human activities.
Sanitary quality of sands from beaches of azores islands
Authors: Mendes B. , Urbano P. , Alves C. , Lapa N. , Morais J. , Nascimento J. , Oliveira J. F. S.
Published: May 2018

An evaluation of the sanitary quality of the sand beaches of Azores archipelago was undertaken May-October 1994 and 1995. The samples were analysed for total and faecal coliforms, faecal enterococci, Clostridium, Pseudomonas aeruginosa and fungi (keratinolytic, yeasts, potential pathogenic and allergic and/or environmental saprophytes). The results were evaluated according to a “Proposal Guideline for the Microbiological Quality of Sand”. The data showed good or satisfactory sanitary quality of the sand beaches. The results indicated that the faecal enterococci can be a better indicator organism than the total and faecal coliforms. The fungi could be used as indicator organisms. The application of the “Proposal” should complete the criteria used in the “Blue Flag” distinction for high environmental quality beaches.
Virus removal by the domestic wastewater treatment system named Johkasou
Authors: Kaneko M.
Published: May 2018

Virus removal by a treatment plant for domestic wastewater (Johkasou), was investigated using a small model of the plant. Under standard BOD loading of 0.076 BOD kg/m3/day, 97% of E. coli phage T2, 98% of poliovirus 1 and 93% of coxsackievirus B3 were removed from inlet wastewater by the system. About 80% of the viruses in the influent were removed in the first and second anaerobic zones under the standard conditions. When the loading was increased to double the standard loading (0.152 kg BOD/m3/day) the removal rate decreased to 64%. Poliovirus 1 and coxsackievirus B3 were removed more easily than T2 phage. Assuming the stream in each zone was completely mixed, the virus reducing activity of microorganisms was estimated by the rate constant of the first order reduction equation. It was found that the higher the BOD loading rates, the lower the values of the constant.
Listeria species incidence and characterisation in a river receiving town sewage from a sewage treatment plant
Authors: Combarro M. P. , González M. , Araujo M. , Amezaga A. C. , Sueiro R. A. , Garrido M. J.
Published: May 2018

This study evaluated the ability of a sewage treatment plant to eliminate Listeria species and the incidence of Listeria species in the river receiving the effluent. The average efficiency of removal of Listeria species in the treatment plant was 92%. Despite the efficiency of the plant being within the limits established by the EC Directive in terms of BOD5 decrease, an increase in the levels of Listeria species was still observed downstream from the plant. The species isolated with greatest frequency, both in the influent and effluent as well as the river water, was L. monocytogenes followed by L. seeligeri and L. welshimeri. L. ivanovii was only found in very low proportions in the river samples. The analysis of the sensitivity of Listeria species to 22 antimicrobial agents demonstrated the presence of a high percentage of bacteria resistant to aztrenam, cefuroxme, cetriaxone and to a leser degree moxalactam and cefotaxime. In contrast, resistance to aminoglycosides and tetracycline was only observed in a low number of isolates.
How good is modelling of microbial survival in fluvial systems?
Authors: Springthorpe V. S. , Loh C. L. , Sattar S. A.
Published: May 2018

In natural and man-made environments microorganisms encounter a number of positive (growth) and negative (toxic and predatory) influences which affect their survival. Understanding microbial survival and potential for regrowth is important for risk assessment in a variety of water types and settings. However, the behaviour of microorganisms in fluvial systems cannot be completely simulated in the laboratory. We have previously studied the survival of several microorganisms in river water in the laboratory and in situ. Frequently our results were variable when sampling sites were separated temporally and spatially. In order to further understand why such differences may occur, we examined the effect of transient nutrient plugs on microbial survival and regrowth in parallel in two model systems with different characteristics: a flow-through hollow fibre diffusion (HFD) system and static diffusion chambers (DC). We focused on the behaviour of Escherichia coli because of its widespread use as an indicator. Results showed a different response of E. coli to transient presence of nutrients in the two systems; both systems responded to nutrient spikes but the HFD system responded more rapidly. For 1h and 2h nutrient spikes, the peak populations in the HFD system were seen 5h (62% net increase) and 8h (650% net increase) after nutrient addition, respectively. In the DC the corresponding figures were 7h (18.5% net increase) and 12h (300% net increase) hours. However, decline in microbial numbers was more rapid in the HFD than the DC system. When this was tested further with repeated short nutrient plugs (10min), the net growth in the CD system was higher than in the HFD. The main question that arises from these studies is under what conditions, if any, does the rapid response HFD model become more relevant for field conditions?
Survival of giardia, cryptosporidium, poliovirus and salmonella in marine waters
Authors: Johnson D. C. , Enriquez C. E. , Pepper I. L. , Davis T. L. , Gerba C. P. , Rose J. B.
Published: May 2018

Discharge of sewage into the ocean is still a common method of disposal worldwide. Both treated and untreated sewage may contain significant concentrations of waterborne pathogens, such as Giardia, Cryptosporidium, poliovirus and Salmonella. Limited studies exist on the survival of poliovirus and Salmonella in marine waters; however, almost no information exists on the survival of protozoan parasites in marine waters. This study examined the survival of Giardia muris cysts, Cryptosporidium parvum oocysts, poliovirus-1 and Salmonella typhimurium in marine waters. The survival of the microorganisms varied according to the presence of light, salinity and water quality (as determined by quantity of enterococci). All microorganisms survived longer in the dark than in sunlight, the order of survival in sunlight being: Cryptosporidium > poliovirus > Giardia > Salmonella.
Virus behaviour within a distribution system
Authors: Quignon F. , Kiene L. , Levi Y. , Sardin M. , Schwartzbrod L.
Published: May 2018

If viruses are introduced into a drinking water distribution system they will be submitted to various phenomena, including inactivation, aggregation, adsorption but the actual inactivation rate is impossible to estimate. A pilot-scale study evaluated the behaviour of viruses sporadically introduced into a distribution system. In particular, phenomena such as virus adsorption onto clay particles or onto pilot surfaces covered by a biofilm, which could provide viruses with a protection against trace amounts of residual disinfectants were studied. Poliovirus 1, pre-adsorbed or not on particles of Na-montmorillonite, was pulse-injected into a pilot distribution system and traced both in the water flow and in the biofilm. The viral responses observed in the water flow at the pilot outlet can be described by a Gamma law or by an analytical model that includes both viral inactivation and adsorption to the biofilm. Pre-adsorption on 40mg/l Na-montmorillonite increases about 3-fold the residence time of the viruses within the pilot. In the presence of chlorine, pre-adsorption on clay does not prevent chlorine inactivation of viruses. In every case, a greater amount of viruses is recovered from the biofilm than from the water flow, by a 2-fold or by a 10-fold factor in the absence or presence of chlorine, respectively. Viral adsorption to biofilm is thus a leading phenomenon that, along with viral inactivation, directs the fate of the viruses introduced into a distribution system and, in particular, allows for their accumulation within the biofilm.
Detection of sewage-derived escherichia coli in a rural stream using multiplex PCR and automated DNA detection
Authors: Turner S. J. , Lewis G. D. , Bellamy A. R.
Published: May 2018

A randomly amplified polymorphic DNA (RAPD) marker, localised to the glycine decarboxylase gene (gcvP) of Escherichia coli, has shown promise for use as a molecular marker for the identification E. coli isolates of human origin. Characterisation of the RAPD polymorphism has enabled development of target-specific primers for direct PCR detection of E. coli of human origin. A field trial was undertaken to investigate the suitability of the marker for detecting E. coli derived from sewage effluent discharged to a rural stream which already contained a substantial background level E. coli of animal origin. Multiplex PCR was performed on E. coli isolates from each sample site using the marker-specific primers in conjunction with primers directed towards a region of the β-glucuronidase (gusA) gene which served as an internal PCR control. Marker-positive strains were detected in raw sewage, treated effluent, stream water collected from immediately downstream of the effluent discharge and from a small tributary which ran down one side of the treatment plant. However, no marker-positive isolates were detected upstream of the treatment plant, despite the relatively high faecal coliform levels (mean = 3.5×103cfu/100ml) recorded at these sites. Further investigations on the side tributary revealed a possible entry point for sewage from the treatment system. Thus the PCR-based approach described here shows promise for the detection of human faecal contamination in rural environments and may be of use for other environmental applications such as the detection of septic tank leachate in rural catchments.
Bacteriophages infecting various bacteroides fragilis strains differ in their capacity to distinguish human from animal faecal pollution
Authors: Puig A. , Jofre J. , Araujo R.
Published: May 2018

Strain HSP40 of Bacteroides fragilis (ATCC 51477) selectively detects bacteriophages excreted by humans. We have tested 115 strains of B. fragilis, isolated from humans, as hosts for the detection of bacteriophages in urban sewage. Only 10% of the strains examined gave counts that were similar to or higher than those given by B. fragilis HSP40. To determine their specificity, some of these were examined for their ability to detect phages in faeces from various animal species and in slaughterhouse wastewater. Two groups of strains were distinguished. The first allowed the recovery of phages in samples with human and animal faecal pollution. The second, which included HSP40, detected phages preferentially in samples with human faecal pollution.
Rapid detection of coliform bacteria and influence of non-target bacteria
Authors: Fiksdal L. , Tryland I. , Nelis H.
Published: May 2018

Enzymatic hydrolysis of fluorogenic substrates (4-methylumbelliferyl-β-D-galactoside, 4-methylumbelliferyl-β-D-glucuronide) has been used for rapid (25min) detection of indicators of faecal water pollution, i.e. coliform and thermotolerant coliform bacteria. In the present work, enzymatic activities and different groups of bacteria (i.e. thermotolerant coliforms, coliforms, β-galactosidase positive and β-glucuronidase positive bacteria) from sewage effluent and polluted river water have been investigated. Ratios of the order of 1:10 between coliforms and β-galactosidase positive bacteria were demonstrated. The contribution from β-galactosidase positive non-coliform bacteria to the measured enzyme activity should not, therefore, be neglected. Numbers of β-glucuronidase positive non-coliforms indicate interference of this group in the rapid assay.
Detection of enterococci with rRNA targeted DNA probes and their use for hygienic drinking water control
Authors: Meier H. , Koob C. , Ludwig W. , Amann R. , Frahm E. , Hoffmann S. , Obst U. , Schleifer K. H.
Published: May 2018

Enterococci are useful indicators of faecal contamination with their high abundance in faeces and long survival in the environment and the possibility of indicating the source of contamination by species identification has lead to discussion of whether enterococci would be more reliable faecal indicators than E. coli. In an attempt to facilitate rapid and accurate identification of enterococci, 16S rRNA targeted oligonucleotide probes were designed by computer-aided analysis of more than 4,000 rRNA sequences. Probes were labelled non-isotopically with digoxigenin and fluorescent dyes. Conditions for specific hybridisation were optimised for dot blot hybridisation and whole cell hybridisation for all probes. With a combination of two probes, all hygienically important enterococci could be detected and 24 biochemically identified environmental isolates also hybridised with one of these probes. A quantitative detection method with a high sensitivity was developed based on filtration of water samples through polycarbonate filters, a short incubation on agar and microcolony filter hybridisation with fluorescently labelled probes followed by epifluorescence microscopy. Within 8–20h sampling a specific identification of enterococcal microcolonies was possible. With this method 15/32 well- and tap-water sources from the Mainz area were identified as being of substandard quality. The proposed method detects faecal contamination significantly earlier than conventional methods and could be helpful in the hygienic monitoring of drinking water.
Biological activity of biofilm and sediment in the Emscher River, Germany
Authors: Bjerre H. Løkkegaard , Hvitved-Jacobsen T. , Schlegel S. , Teichgräber B.
Published: May 2018

Investigations were performed on biofilm and sediment from the river Emscher, Germany, presently acting as a large wastewater collector. Biofilm laboratory batch experiments were performed under aerobic and anaerobic conditions. The aerobic biofilm surface activity in terms of dissolved oxygen (DO) consumption was determined. Under anaerobic conditions the sulfide production was investigated. Laboratory biofilm experiments were compared with full scale studies performed under aerobic and anaerobic conditions to determine the total biofilm and sediment activity at selected reaches of the Emscher. The biofilm and sediment activity determined may be used for modelling of wastewater quality changes in the Emscher.
Biological denitrification in a continuous flow membrane reactor
Authors: Mansell Bruce O. , Schroeder Edward D.
Published: May 2018

Biological denitrification in a continuous flow membrane reactor has been investigated. The nitrate-laden water treated was separated from a suspended denitrifying culture by a 0.02 μm average pore diameter membrane. Equal pressure was maintained across the membrane and nitrate was removed by molecular diffusion through the membrane and into the denitrifying culture. A nitrate removal efficiency of approximately 90% or a flux of 4 g NO3−-N/m2/d of membrane area was achieved with an influent concentration of 20 mg/L NO3−-N. A mathematical model was developed to approximate system performance. Predicted effluent concentrations for the experiments conducted were 5.7, 9.5, 11.7, and 17.6 mg/L NO3−-N. The respective measured effluent concentrations were 2.3, 6.0, 9.0, and 16.0 mg/L NO3−-N.
Cell biomass and exopolymer composition in sewer biofilms
Authors: Jahn Andreas , Nielsen Per Halkjær
Published: May 2018

During wastewater transportation in sewers conversion of organic matter into biomass takes place in bulk water and in bacterial biofilms. The biomass amount, the composition and the properties influences wastewater composition and the subsequent fate in the wastewater treatment plant. Because the biomass consists of both cell biomass and extracellular polymers having different properties, the biomass composition in biofilms from three different gravity sewers is reported here. Cell biomass was only a minor fraction of the organic matter in the biofilms and 70-98% of total organic carbon was found to be extracellular. The macromolecular composition of the biofilm was determined and the major part was protein. Also in the extracellular fraction protein was the largest fraction. Moreover, humic substances, polysaccharide, uronic acids and DNA could be extracted from all biofilm samples into an extracellular fraction. Between 30 and 40% of the COD from the total biofilm sample were not analysed by the methods used. Some variation in the content and composition of extracellular material was found among the different sewer lines. The results demonstrate that biofilm material from sewer lines entering a wastewater treatment plant mainly consists of heterogeneous extracellular organic material with protein as the dominating fraction.
Post denitrification in a moving bed biofilm reactor process
Authors: Aspegren Henrik , Nyberg Ulf , Andersson Bengt , Gotthardsson Sören , Jansen Jes la Cour
Published: May 2018

The Sjölunda wastewater treatment plant in Malmö Sweden will have to comply with future effluent standards of less than 10 mg BOD7/l, 8 mg N/l and 0.3 mg P/l. The upgrading for enhanced nutrient removal will be based on a site-specific concept where a tertiary treatment step for post-denitrification will be required. An interesting process in this respect is the moving bed biofilm reactor (MBBR). The number of practical experiences with this type of process is however still limited. In this paper the results from a pilot plant test are presented. The primary aim of the experiment was to demonstrate the MBBR process as part of an overall concept for nutrient removal at the Sjölunda WWTP. Two different carbon sources, ethanol and methanol were tested. In addition the effect of low phosphate concentrations on the process performance was investigated.
The application of settling velocity as a parameter for characterising wastewater solids
Authors: Hedges Peter D. , Becker Fiona A. , Smisson Robert P.M.
Published: May 2018

A research programme at Aston University, the aim of which was to investigate the distribution of chemicals within the settling velocity grading curve of suspended sewage solids, has recently been completed. The pollutants investigated were COD, TKN, Phosphorous and a suite of 7 metals. Tables summarising their distributions, and the range of values observed, are presented in the paper. Although the 15 sites studied were divided into large, medium and small classes, no evidence was found to indicate that catchment size influences the distribution of chemicals significantly. However, the TKN and P loadings tended to be higher for small catchments. This is probably due to a greater proportion of their area being rural, than in the medium and large catchments. It is pointed out that when differing units are used to present the results, different conclusions can be drawn regarding the settling velocity fraction which carries the heaviest pollutant load.
Transformations of wastewater organic matter in sewers under changing aerobic/anaerobic conditions
Authors: Tanaka Naoya , Hvitved-Jacobsen Thorkild
Published: May 2018

Transformations of organic matter in domestic wastewater under changing aerobic/anaerobic conditions were studied in laboratory scale reactors and in a real pressure sewer emphasizing measurements of oxygen utilization rate (OUR). During 3-10 hours of anaerobic conditions, the aerobic, heterotrophic biomass was maintained and a net production of readily biodegradable substrate originating from hydrolyzable substrate was observed. A process model description which includes aerobic and anaerobic processes in the bulk water phase as well as in the biofilm was presented and model parameters were determined from OUR measurements. Based on experimental findings, it was possible to simulate wastewater quality changes in terms of organic matter under transient aerobic/anaerobic conditions in sewer systems.
The influence of near bed solids transport on first foul flush in combined sewers
Authors: Arthur S. , Ashley R. M.
Published: May 2018

The problems associated with deposited sediments in sewers, and their transport through sewer systems have been the subject of detailed fieldwork programmes in the UK, and elsewhere in Europe. Existing laboratory, and some field based research exercises have focused on the relatively small, discrete particles. It is clear, however, that combined sewer systems have inputs which comprise of a significant proportion of large organic solids (faecal and food wastes), as well as the finer range of particle sizes. The increased concern regarding CSO spills into the environment has fuelled the recent development of sewer flow quality models, such as HYDROWORKS QM and MOUSETRAP, some of which make no attempt to represent the transport of these larger organic particles. Herein, the results of a collaborative research programme undertaken between three UK universities and a water authority are discussed. Transport at the bed in sewers, as “near bed solids”, is defined. Based on a comprehensive data collection program undertaken in the Dundee combined sewerage system, a method is presented which may be used to estimate the rate of sediment transport near the bed in sewers. The influence that solids in transport near the bed have on first foul flush in combined sewers is discussed. A methodology is proposed which may be used to estimate the extent to which sediment in transport near the bed in sewers contributes to first foul flush phenomena, by describing the movement of a storm wave along a conceptual sewer length.
Specific oxygen uptake, nitrification and denitrification rates of a zinc-added anoxic/oxic activated sludge process
Authors: Panswad T. , Polprucksa P.
Published: May 2018

The specific oxygen uptake rate (SOUR), specific nitrification rate (SNR) and specific denitrification rate (SDNR) of an anoxic-oxic activated sludge process fed with zinc-added synthetic wastewaters were investigated. Two different characteristics of synthetic wastewaters were used, i.e., 500 mg/l COD, 40 mg/l TKN and 10 mg/l P (representing normal COD load) for Model A while 3500 mg/l COD, 175 mg/l TKN and 25 mg/l P (representing high COD load) for Model B. The zinc doses varied from 0 (control) to 10, 25, 35 and 50 mg/l. When the two systems reached steady states, they were further shocked with 300 mg/l zinc for 4 consecutive days before returning to their initial conditions. The SRT and F/M ratio of both models were 10 days and 0.26-0.47 day−1, respectively. The endogenous SOURs of both models were not much affected by the increase of zinc concentration. They were about 7.5 to 10 and 9.4 to 11.5 mg O2/g MLSS-hr, for Models A and B, respectively. In Model A, as the zinc increased from 0 to 50 mg/l, the SNRs dropped from 4.0 to 1.4 mg NH4+-N /g MLSS-hr whereas the initial SDNRs fell from 19.6 to 5.3 mg NO3− /g MLSS-hr. Meanwhile, the SNRs of Model B were relatively constant (1.5-1.8 mg NH4+-N /g MLSS-hr) while the initial SDNRs dropped from 16.2 to 8.3 mg NO3− /g MLSS-hr. That is, under high COD load conditions, the zinc dose applied here did not significantly affect the carbon removing heterotrophs and nitrifiers while a slight effect was seen on the denitrifiers and significant retardation was observed for both nitrifiers and denitrifiers in case of normal COD load. During the shock period, the SNRs of Model A dropped to 0.67 to 1.26 mg NH4+-N /g MLSS-hr whereas the initial SDNRs decreased drastically to 1.5 to 3.0 mg NO3− /g MLSS-hr. The impact from the zinc shock in such circumstances was obviously higher on the denitrifiers than on the nitrifiers. In Model B, the SNRs were 0.77 to 1.5 mg NH4+-N /g MLSS-hr and the initial SDNRs were 2.9 to 6.18 mg NO3− /g MLSS-hr. Not much effect on nitrifiers was evident in this case. For Model A, the recoverability of the heterotrophs and the nitrifiers was not so good, while that of the denitrifiers was quite satisfactory. However for Model B, those recuperation abilities were comparable for all three organisms. The data therefore suggested that there may be some differences in the species domain between the carbon removing microorganisms and the denitrifiers, however, further investigations for confirmation are required.
Effect of wastewater composition on microbial populations in biological phosphorus removal processes
Authors: Wang J. C. , Park J. K.
Published: May 2018

Bench-scale sequential batch reactors (SBRs) were fed with glucose- and acetate-containing synthetic wastewaters to evaluate microbial population dynamics and types of phosphorus-accumulating organisms (PAOs) using a cellular fatty acid profile analysis. The phosphorus content in the sludge was 38% (w/w) for the acetate-fed SBR and 20% (w/w) for the glucose-fed SBR with a VSS/TSS ratio of 50%. Glucose-fed PAOs were found to remove phosphorus with accumulation of glycogen in cells without synthesizing poly-β-hydroxybutyrate (PHB) at influent phosphorus concentration < 20 mg-P/L and nitrate concentration < 2 mg-N/L. From the fatty acid profile biomarker study, it was found that the glucose-fed SBR maintained the same fatty acid profile before and after biological phosphorus removal (BPR) occurred while the acetate-fed SBR had a different fatty acid profile. The microbial population in the glucose-fed SBR was significantly different in terms of metabolic behavior and cellular fatty acid profile from that introduced in the acetate-fed SBR. Fatty acid a15:0 (anteiso methyl-branching) was abundant in the glucose-fed PAOs. Among the five PAO candidates (Acinetobacter, Pseudomonas, Arthrobacter, Aeromonas, and Micrococcus), only Arthrobacter spp. had the biomarker of fatty acid a15:0, indicating that Arthrobacter spp. may be one of the PAOs existing in the glucose-fed bioreactors.
Sediment transport model in sewer networks - a new utilisation of the Velikanov model
Authors: Zug M. , Bellefleur D. , Phan L. , Scrivener O.
Published: May 2018

This paper presents the application of the conceptual total load model of Velikanov through a description of the solids behaviour, its calibration using numerical optimisation and the results on real sites. In order to take into account the full scale measurements, the Velikanov's model has been included in a global model for solid production and transport in sewer system which is divided into four modules: hydrologic, hydraulic (Muskingum model), pollution (build-up, wash off and total load) and calibration functions. The calibration of Velikanov parameters has been made using a procedure of numerical optimisation based on the Powell method. The solids behaviour is characterised by settling velocity (ωs) and density (s) which varies between fine particles (ωs=5.4m/h and s=2.00) essentially transported in suspension and coarse particles (ωs=45m/h and s=2.65). The results of the calibration phase on three real French sites which presented dry weather sediments and the validation phase can be considered of good quality. Simultaneous measurements of rainfall, hydraulic and TSS concentration allowed a large range of calibration and validation. This model provides a satisfying fitting of the real TSS pollutographs and this, considering the global form, maximal value and the temporal position.
Six years of pilot plant studies for design of treatment plants for nutrient removal
Authors: Harremoës P. , Haarbo A. , Winther-Nielsen M. , Thirsing C.
Published: May 2018

The decision to upgrade the treatment plants of the City of Copenhagen to include nutrient removal was made in 1989. At the same time, it was decided that intensive pilot plant studies should be initiated in combination with wastewater characterisation. The pilot plant studies were designed to suit kinetic interpretation of plant performances including wide variations of operation to identify the process limitations. It soon became apparent that the limiting factors with respect to nitrogen removal were temperature, rate of nitrification and the availability of sufficient carbon and energy sources for denitrification. The study included a literature survey to identify a reference growth rate of nitrifiers, study of temperature conditions of future plant operation during winter periods, nitrification rates in the pilot plant under temperature control and identification of nitrification inhibition, plus analysis of carbon and energy sources for denitrification. The result was that the inhibition was significant, and several performance break-downs were experienced from 1989 to 1991. Intensive programmes have identified inhibition from industrial regions in the city and internal recycles in the treatment plant. The inhibition has been reduced considerably over a six-year-period.
A conceptual CSO emission model: SEWSIM
Authors: Ruan Mingchuan , Wiggers Jan. B. M.
Published: May 2018

CSO emission is widely considered a significant pollution source to receiving waters in urban areas. The existing deterministic sewer models are not able to predict CSO emission effectively. In this study, a conceptual CSO emission model SEWSIM has been developed using a powerful programming package MATLAB and SIMULINK. A sewer system consisting of an impervious catchment and a sewer network is schematised as two linear dynamic reservoirs. The following physical processes are conceptually modelled: rainfall-runoff; surface solids buildup and washoff; sewer sediment erosion and deposition. The model is suitable for both event-based and continuous simulations. Some simulation results demonstrate that SEWSIM predicts pollution load of CSO emission more effectively than deterministic models.
Nutrient control with other sludges in anaerobic digestion of BPR sludge
Authors: Hwang Ho-Jae , Choi Euiso
Published: May 2018

Nutrient released from BPR sludge during anaerobic digestion was refixed with Ca2+ and Mg2+ ions as calcium phosphate and struvite. The higher contents of Ca and Mg in primary sludge and nightsoil showed potentialities to control the nutrient returning back to liquid stream when these sludges were mixed with BPR sludge. Addition of Mg2+ to BPR sludge was also effective. The amount of TP removed from a sludge could be computed from the amount of P refixed by the amount of Ca and Mg removed during digestion. About 40 to 45% of TP and 35 to 39% of TN removal efficiencies could be expected when primary sludge or nightsoil was added to BPR sludge with a volumetric ratio of 0.67/1. With 100mg/L of Mg2+ addition (Ca/Mg molar ratio of 0.81) to BPR sludge, TN and TP removal efficiencies were 52.3% and 58.4%, respectively.
An integrated duckweed and algae pond system for nitrogen removal and renovation
Authors: van der Steen Peter , Brenner Asher , Oron Gideon
Published: May 2018

An integrated pond system, consisting of duckweed and algae ponds, was investigated for duckweed production and for further treatment of anaerobically treated domestic wastewater. The system consisted of 10 ponds in series, arranged in 3 stages of 2 duckweed ponds, 3 algae ponds and 5 duckweed ponds, respectively. Production of duckweed ranged from 7.4-16.4 g/(m2.day) (or 27-60 ton/(ha.year)) dry weight in the first pond, to 2.7-8.2 g/(m2.day) (or 10-30 ton/(ha.year)) in the last pond. Regression analysis suggested that the production was positively influenced by the concentration of organic compounds in the pond water. The ammonium concentration in the range of 20-60 mg/l NH4-N did not affect duckweed production. Fifty-six percent of the pond influent nitrogen, mainly ammonium, was removed. Ammonium removal was due to uptake by the duckweed plants (18%), nitrification (3%), sedimentation (8%) and combined volatilization of NH3 and denitrification (73%).
Optimisation and control of the inflow to a wastewater treatment plant using integrated modelling tools
Authors: Mark Ole , Hernebring Claes , Magnusson Peter
Published: May 2018

The present paper describes the Helsingborg Pilot Project, a part of the Technology Validation Project: “Integrated Wastewater” (TVP) under the EU Innovation Programme. The objective of the Helsingborg Pilot Project is to demonstrate implementation of integrated tools for the simulation of the sewer system and the wastewater treatment plant (WWTP), both in the analyses and the operational phases. The paper deals with the programme for investigating the impact of real time control (RTC) on the performance of the sewer system and wastewater treatment plant. As the project still is in a very early phase, this paper focuses on the modelling of the transport of pollutants and the evaluation of the effect on the sediment deposition pattern from the implementation of real time control in the sewer system.
Control of Cryptosporidium: from reservoirs to clarifiers to filters
Authors: Edzwald James K. , Kelley Michael B.
Published: May 2018

Control of Cryptosporidium in potable waters requires an integrated multiple barrier approach of source water protection of water supply reservoirs and treatment technology through clarification, filtration, and disinfection. Pristine lakes and protected reservoirs have far lower concentrations of oocysts (mean values less than 10 oocysts/100 L) than unprotected supplies. Coagulation is critical to the effective control of Cryptosporidium by clarification and filtration. Coagulation conditions that produce filtered waters of low turbidities, particle counts, and effectively remove natural organic matter also produce high removals of Cryptosporidium. Dissolved air flotation (DAF) can achieve oocyst removals of 3 log compared to about 1 log by sedimentation. DAF and filtration provide two effective barriers to Cryptosporidium with cumulative log removals of 4 to 5 compared to log removals of 3 to 4 by sedimentation and filtration.
Management and treatment of algae in lowland reservoirs in Eastern England
Authors: Daldorph Peter W. G.
Published: May 2018

Pumped storage reservoirs receiving river water from lowland catchments, such as those operated by Anglian Water in Eastern England, tend to have large inputs of nutrients and consequently suffer from large populations of algae. The current paper describes some measures taken at Grafham Water, one of the largest reservoirs in the U.K., to control algae and remove algal cells and algal products during the water treatment process. Marked changes in the algal community were observed following the installation of a destratification system with a decline in cyanobacteria in particular. Improvements have been made to the water treatment process including the installation of triple layer filters, ozonation and GAC absorbers. The penetration of algal cells through treatment is described before and after these modifications showing substantial improvements. Reductions were also achieved in THM and T.O.C. concentrations in the treated water.
Influence of sludge cake concentration on the operating variables in incineration by different types of furnaces
Authors: Mininni Giuseppe , Lotito Vincenzo , Passino Roberto , Spinosa Ludovico
Published: May 2018

The influence of cake concentration on fuel consumption, air requirement and flue gas production in incineration of sewage sludge is discussed. Fluidized bed (FBF), multiple hearth (MHF) and rotary kiln (RKF) furnaces are considered as alternatives together with the optional use of an afterburning chamber where exhaust gases are taken at 950°C for 2 s with an oxygen concentration of 6% by volume. It clearly appears that, if an afterburning chamber is used, and total minimum fuel consumption can be achieved at an optimal value of cake concentration (45.9% for FBF and 32.5% for MHF) when autogenous conditions are reached in the furnace and air addition is no longer needed in the afterburning chamber. At higher concentrations, abundant exhaust gas productions, due to the dilution air needed in the furnace, can considerably increase fuel consumption in the afterburning chamber, especially in MHF operation. In the rotary kiln furnace, fuel requirement decreases over the whole range of cake concentration as no conditions for autogenous combustion in the furnace can be achieved.
Concept for an interlinked system of a sludge drying facility and a landfill for residual waste
Authors: Brautlecht P. , Gredigk S.
Published: May 2018

The integration of a sewage sludge drying facility into landfill operation leads to a large number of synergistic effects. Two of these modules are examined more closely in this paper. If the thermal and electric energy produced in landfill operation are used for sewage sludge drying, the drying costs will be able to be reduced and the existing resources will be used in an ecologically acceptable way throughout the year. The joint treatment of the vent condensates resulting from sewage sludge drying and of landfill leachate suggests itself because both wastewaters show a similar composition. Tests carried out for this purpose have revealed that the efficiencies achieved especially in joint biological treatment are very high due to the good biodegradability of the vent condensates. Negative effects from the joint treatment of vent condensates on other procedures examined were not observed. With the help of comprehensive interlinked systems sewage sludge drying can even be realized in rural areas. This contributes to higher safety in sewage sludge disposal under economic, ecological and future-oriented aspects.
Anaerobic digestion of co-mingled municipal solid waste and sewage sludge
Authors: Hamzawi N. , Kennedy K. J. , McLean D. D.
Published: May 2018

This study evaluated the technical feasibility of the anaerobic co-digestion process in the context of typical North American solid waste. Using biological activity tests, an optimal mixture was identified with 25% organic fraction of municipal solid waste (OFMSW) and 75% sewage sludge (65% raw primary sludge (RAW), 35% thickened WAS (TWAS)) based on biogas production. Also, based on the rate of biogas production, the most anaerobically biodegradable components of the OFMSW were paper and grass. The TWAS and the newspaper were found to be the least biodegradable components. Lab-scale testing indicated that alkaline pretreatment increased the biodegradability of the sewage sludge/OFMSW mixture the most, as compared to the untreated control. Thermochemically pretreated feedstocks inhibited anaerobic biodegradability as compared to the control, whereas the anaerobic biodegradability of thermally pretreated feed was not found to be significantly different from that of the control. Empirical models were developed based on alkaline dose, feed total solids concentration and particle size for biogas production and removal of TS and VS. All three experimental factors were found to be significant with respect to the response variables studied.
Dynamics of methanogenic activities in a landfill bioreactor treating the organic fraction of municipal solid wastes
Authors: Lay J. J. , Li Y. Y. , Noike T.
Published: May 2018

A bench-scale investigation was conducted to evaluate the dynamics of methanogenic activities in a landfill bioreactor (LFBR) treating the organic fraction of municipal solid wastes (OFMSW). The specific methanogenic activity (SMA) test was used to measure each individual methanogenic activity on degrading carbohydrate, protein, lipid, butyrate, propionate, and acetate at an interval of one-year. A simple model incorporating three biokinetic parameters, namely lag-phase time, methane production rate and methane production potential, was employed to systematically describe the dynamics of SMA on the anaerobic mineralization of the OFMSW in an LFBR. The results indicate that the model is suitable to describe the dynamics of SMA in the LFBR. According to the dynamics of the SMA, the decomposition of proteins and lipids overruled the stabilization of the LFBR, while the rate of methanogenesis was higher than that of acetogenesis. Comparing the estimation and the observation of methane production rates suggested that the period of the critical incubation time (λ*) of the protein and the lipid influenced the efficiency of the LFBR.
Chemodynamics, transport behaviour and treatment of phthalic acid esters in municipal landfill leachates
Authors: Bauer M. J. , Herrmann R. , Martin A. , Zellmann H.
Published: May 2018

Large amounts of phthalic acid esters (PAEs) are leached from plastics dumped at municipal landfills. This leachate transports PAEs either adsorbed on particulate matter or in dissolved phase. Dissolved organic macromolecules, mainly humic-like substances, enhance the solubility of PAEs. In the biochemical environments of municipal landfills short chain PAEs can be degraded by base-catalyzed hydrolysis or by microorganisms which enzymatically split the side chains. However, there is no cleavage of the aromatic ring. Long chain PAEs like di-(2-ethylhexyl) phthalate are neither degraded abiotically nor by microorganisms. Hence, these PAEs can be leached and washed out of leaky landfills into the groundwater and thus continue to be a threat to the aquatic environment. Only a combined UV radiation/ozonation treatment is capable of fully destroying PAEs.
Change of chemical and biological water environment at a newly constructed reservoir
Authors: Ioriya Teru , Inoue Satoshi , Haga Masaru , Yogo Noriaki
Published: May 2018

The changes of chemical and biological water environment of Lake Sapporo were investigated for over eight years from the beginning of water storage, and this is the first detailed report concerning the reservoirs situated in sub-frigid zones in Japan. The pollution load flowing into this reservoir is only nature-derived. At Lake Sapporo, the large inflow of water from the melting snow in spring supplies the middle and bottom layers with oxygen, and replaces water in the reservoir with new water. Under these circumstances, after effects of the initial deterioration were detected during two years in water quality, three years in phytoplankton composition and four years in zooplankton composition.
Statistical analysis of freshwater red tide in Japanese reservoirs
Authors: Fukuju Shinya , Takahashi Tadashi , Kawayoke Takahiro
Published: May 2018

This study introduces the collated results regarding the occurrence of freshwater red tide, the associated deterioration of water quality and the performance of countermeasures based on a survey of freshwater red tide conducted from 1992 to 1993. It also reports the results of an examination of the characteristic of reservoirs in which freshwater red tide occurs and control factors for occurrence according to multivariate analysis. Based on these results, a freshwater red tide occurrence prediction model was constructed using discriminant analysis, and this study further reports the results of applying this model to dams under construction.
Algal control and destratification at Hanningfield Reservoir
Authors: Simmons Jeremy
Published: May 2018

In May 1994 an artificial destratification system was installed at the eutrophic 27,200ML Hanningfield raw water reservoir in Essex U.K. The main objective of this installation was to prevent poor raw water quality, which can result from hypolimnetic isolation in the Summer months when thermal stratification often occurs. By adopting an intermittent destratification strategy to constantly change reservoir conditions thus promoting competition amongst algae, it is hoped that an overall decrease in annual phytoplankton biomass at the reservoir will result. This in turn will reduce the pressure on the raw water treatment processes required to produce a potable water supply. This paper evaluates algal, meteorological, and other monitored variables to assess the effect of destratification on Hanningfield Reservoirs phytoplankton community from 1994 to 1996. Although noting the limited data period the results show little dominant phytoplankton type changes, but notes a fall of 66% in mean total biomass in 1996 compared to 1994 values.