bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of acclimating saccharides on the activated sludge bacterial population: composition abnormality of activated sludge acclimated to glucose
Authors: Ubukata Yuu , Takii Susumu
Published: May 2018

The question of whether the substitution of glucose for starch in municipal sewage as an acclimating saccharide for activated sludge (AS) in the laboratory is valid was investigated using activated sludges acclimated to glucose (G-AS) and dextrin (D-AS), since the bacteria responsible for starch (dextrin) removal in D-AS are verified to take up maltose instead of glucose during dextrin removal. In G-AS, polysaccharides are the major reserve materials, and large amounts of residual organic materials (ROM) are excreted from the AS. In contrast, in D-AS, about half of the reserve materials are low molecular weight saccharides, and no appreciable amount of ROM was detected. It is considered that most bacteria responsible for the removal of dextrin and glucose are Gram-negative and Gram-positive, respectively, based on the results of the chemical composition of AS and the type of reserve saccharide. As a result, in laboratory-scale AS processes, maltose (disaccharide) or dextrin (polysaccharide), instead of glucose (monosaccharide), should be used as a substitute for starch.
Population dynamics of chromate reducing bacteria in a bioreactor system developed for the treatment of chromate wastewater
Authors: Nozawa Mamie , Hu Hong-Ying , Fujie Koichi , Tsuchida Tomohiko , Urano Kohei
Published: May 2018

The population dynamics of microbes was investigated in a bioreactor system for the treatment of chromate wastewater supplemented with chromate reducing bacteria Enterobacter cloacae strain HO-1. In this study, respiratory quinone profile and PCR techniques were used to analyse the microbial population. The change in microbial community structure and density was observed on the basis of the respiratory quinone profile since the predominant quinone of HO-1 is ubiquinone-8 (Q-8) and the amount of quinone is proportional to the cell mass. the quantity of microbes and the Q-8 fraction of the total quinones were increased after cultivation with aeration, while long-term operation brought about a decrease in the fraction of Q-8. In addition, the amount of HO-1 was determined by the PCR amplification rate under conditions where the amplification was exponential to the reaction cycles. The cell density of HO-1 and total microbes determined from these procedures compared well with the numbers of HO-1 cells counted selectively using agar plates containing chromate.
Biofilm dynamics studied with microsensors and molecular techniques
Authors: Santegoeds Cecilia M. , Muyzer Gerard , de Beer Dirk
Published: May 2018

Here we present preliminary data on the development of a biofilm from a wastewater treatment plant studied with microsensors and molecular techniques. The development during biofilm growth of oxygen, sulfide and pH profiles was measured with microsensors. Anoxic zones developed within one week and further increased during the following weeks. However, sulfide production was delayed and was first detected in a six-week-old biofilm. With denaturing gradient gel electrophoresis (DGGE) of PCR-amplified 16S rRNA gene fragments the sequence of the bacterial community was followed showing an increasing complexity of the biofilm community during development. In a mature biofilm the influence of nitrate on sulfide production was studied by measuring oxygen, sulfide, pH, nitrite and nitrate profiles with microsensors. Sulfide production was detected deeper in the biofilm and in lower concentrations, when nitrate was added to the medium. The DGGE pattern of the mature biofilm showed both differences and similarities with the DGGE pattern of the 12-week-old biofilm. In particular the RNA pattern changed when nitrate was added to the medium, indicating a change in activity of certain strains.
Pollution prevention in the oil and soap industry: a case study
Authors: Abou-Elela Sohair I. , Zaher F.
Published: May 2018

Industrial audit of a complex oil and soap factory has been carried out. The factory produces edible oils, fatty acids, soap, crude, industrial and pharmaceutical glycerin, powdered detergents, animal fodder, sodium and potassium silicates, sodium hypochlorite and hypochloric acid. The audit shows that there were a wide range of pollution prevention opportunities which could be implemented with significant financial advantages for the factory as well as reducing environmental pollution. Cost benefits for the recommended environmental improvements have been estimated. Many of the improvements had short payback periods.
Bacterial structure of biofilms in wastewater infiltration systems
Authors: Pell Mikael , Stenberg Bo , Hallin Sara
Published: May 2018

The objective of the present study was to use a test system for clustering and characterizing the bacterial populations in five wastewater infiltration systems ranging in size from 12 m2 to 1960 m2 (corresponding to the demand for 4-500 population equivalents). From each system two sand samples were taken and from each sample 88 bacterial isolates were collected. Every isolate was exposed to 52 physiological and biochemical tests. The resulting 880 objects × 52 variable data matrix was subjected to principal components analysis (PCA). After a variable reduction the PCA model revealed a scattered bacteria pattern (score plot) in parts of the sand filters expected to have high loading rates of wastewater, e.g. at the inlet of the filters. This indicates that a diverse bacterial population had developed in response to the carbon and energy source in the wastewater. In contrast to this pattern a more narrow bacteria pattern had developed in low loaded parts of the sand filter. The most important variables explaining the structure of the microbial biofilm at high wastewater load were the ability to ferment sugars and the capacity to sustain different pH levels. The potential to ammonify and grow on nutrient broth was also an important feature. In conclusion, the bacterial test system together with PCA seems to be a useful tool to evaluate the function of a bacterial sand-filter ecosystem.
Population dynamics using temporal series analysis in a industrial two-stage activated sludge pilot plant
Authors: Bécares Eloy , Romo Susana , Fernandez-Aláez Margarita
Published: May 2018

A time series analysis using an autocorrelation function (ACF) was used to assess the relative importance of density (DD) and non density-dependent - (NDD) factors on microfauna abundance of a two-stage activated sludge pilot plant treating industrial effluents. Although some previous work has detected a carrying capacity for the total microfauna abundance in both reactors, ACF showed a general pattern of non-density dependent abundance regulation. Stationarity due to density-dependent factors was observed for the two major species in the first reactor, the sessile Opercularia asymmetrica and the crawling Chilodonatella minuta. There was no evidence of bacterial competition and only weak evidence of floc surface competition. It is possible that the main driving factor in the first reactor was the constant wasting rate. In the second reactor, the microfauna was clearly dependent on substrate fluctuations, attaining densities one order of magnitude higher than in the first reactor. This was probably a consequence of its longer sludge age. An 8-day oscillation period was detected only in the first reactor, while a second oscillation of about 30 days was observed in both the first and second reactors. ACF was shown to be a simple method for discriminating between DD and NDD factors influencing species and total abundance dynamics.
Oscillating conditions for influencing the composition of mixed biological cultures
Authors: Horntvedt Bjarne R. , Rambekk Morten , Bakke Rune
Published: May 2018

This paper presents a strategy in which mixed biological cultures are exposed to oscillating concentration levels, to improve the potential for coexistence of desired bacterial species. A mechanistic mathematical model is constructed to investigate and illustrate this strategy. This paper is focused on competition between nitrifying, denitrifying and aerobic heterotrophic bacteria in a CSTR with sludge recycle. For nitrifying and aerobic heterotrophic cultures, the effect of sinusoidal oscillations in DO levels with an amplitude of 1.0 mg/l is a 16% specific growth rate reduction compared to that at a constant DO level. The denitrifiers growth rate is increased by an average of 59%, compared to the constant DO level situation. A similar strategy has been tested in a pilot plant. It is concluded that the influence on specific growth rates is a function of the amplitude of the oscillations. The effects are greatest when concentrations fluctuate around the half saturation concentration of the rate limiting component(s).
Beginning a molecular analysis of the eukaryal community in activated sludge
Authors: Marsh Terence L. , Liu Wen-Tso , Forney Larry J. , Hans Cheng
Published: May 2018

As a means to furthering our understanding of the eukaryal community in activated sludge, we have applied contemporary molecular techniques to an activated sludge community maintained in a laboratory-scale bioreactor. The initial inoculum was derived from a local wastewater treatment facility in East Lansing, MI and maintained with continuous aeration and a daily feeding regime that included glucose and peptone. Samples were taken on a weekly basis for 5 weeks and community DNA was extracted from 2-5 ml of activated sludge. Using a variety of oligonucleotide primers specific to eukaryotic small subunit ribosomal DNA, we PCR amplified rDNA from the total community DNA. PCR products were analyzed by three techniques, denaturing gradient gel electrophoresis (DGGE), terminal restriction fragment length polymorphism (T-RFLP) and comparative sequence analysis of rDNA clones. Over the course of 5 weeks, analysis with DGGE revealed dramatic changes in the eukaryotic community based on differences in denaturation profiles. However, the analysis is limited to 5-6 bands corresponding to 5-6 different “ribotypes”. Analysis with T-RFLP also suggests changes to the eukaryotic community over time. Both increases and decreases in population size can be detected as a function of time. Up to 15 different terminal restriction fragments can be detected with T-RFLP indicating that this technique is considerably more sensitive than DGGE. Phylogenetic analysis of partial sequences from 11 cloned rDNAs indicate that all 11 clones are from the Ciliophora phylum.
The distribution and movement of polyphosphate and associated cations in sludges from NDEBPR plants in different configurations at pilot scale
Authors: Lindrea K. C. , Lockwood G. , Majone M.
Published: May 2018

A gradual change in the mode and location of intracellular storage of polyphosphate was observed during a long-term pilot-scale evaluation of operating efficiency of a number of EBPR process configurations used for model calibration. The location of intracellular polyphosphate, (defined by the extraction procedure), was seen to change from a long chain form to a lower molecular weight or short chain form under the influence of nitrate return to the anaerobic zone, which was related to a number of factors including influent character (TKN/COD, influent RBCOD) and process configuration, however during trials with high TKN/COD (≥0.13) the storage of polyphosphate was observed to exist predominately in the short chain form. The behaviour of EBPR biomass in a sequencing batch reactor demonstrated mobilisation and storage of polyphosphate from only the low MW form.
Effect of external shipping traffic on the transport of polluted sediments into the inner city canals of Delft (The Netherlands)
Authors: Kelderman P. , Kassie Dessalegn Bezabih , Bijlsma M. , Okonkwo L. C. , Doppenberg A. A. T.
Published: May 2018

The effect of external shipping traffic on the transport of polluted sediments into the inner city canals of Delft was investigated in a field study, measuring flow velocities and suspended solids contents in the water prior to, during and directly after passage of commercial vessels on the main navigation canal bordering the inner city canal system. Turbulent conditions caused strongly increased flow rates, viz. up to 1 m/sec. These flows were dominantly directed inwards, thus causing a net accumulation of pollutant-loaded sediment material inside the Delft inner city canals.

Mass budget calculations as well as sludge thickness measurements revealed that of the ca. 520 tons of sludge material imported annually, about 40% can be attributed to external shipping traffic.

The above observations were further supported in experiments with sediment traps located at stations within, as well as outside, the influence of the external shipping traffic. Here, also an apparent import of heavy metals (Pb, Zn, Cu), attached to the sludge material, could be observed.
Near-infrared spectroscopy as a potential method for routine sediment analysis to improve rapidity and efficiency
Authors: Malley Diane F.
Published: May 2018

The potential for improvement in the rapidity, cost-effectiveness, and efficiency of sediment analysis by the application of near-infrared reflectance spectroscopy (NIRS) is recognized. The rapid (<2 min), non-chemical, non-destructive analytical technique of near-infrared (700–2500 nm) spectroscopy combines applied spectroscopy and complex statistics. It has been used for the experimental analysis of various constituents and functions of soils since the 1960s, and applications for the analysis of sediments are currently being explored. For application of NIRS, sediment samples require little preparation, other than drying, and the samples are not subject to the manipulations of conventional analytical techniques. The spectral information recorded in a 2 min scan can be used to predict numerous constituents and parameters on the samples once appropriate calibration equations have been prepared from sets of samples analyzed by both NIRS and conventional analytical techniques. Constituents and properties of soil and/or sediment analyzed by NIRS technology include moisture, organic matter content, organic C, CO3=, N, P, S, K, Ca, Mg, clay content, humic acids, lignin, cellulose, metal oxides, heavy metals, aggregate size, and inferred past pH of lakes. Several areas are identified where further research is needed to prepare for the application of NIRS to the routine analysis of sediments.
Harbour sludge as barrier material in landfill cover systems
Authors: Tresselt K. , Miehlich G. , Groengroeft A. , Melchior S. , Berger K. , Harms C.
Published: May 2018

Sediment dredged from the port of Hamburg is treated and stored upland in a storage facility. The site is covered by a system of topsoil above a sand drainage layer and a barrier layer made of processed harbour sludge in order to minimize the input of water after completion of the site. In 1995 in-situ investigations have started to study the hydraulic properties, the water balance and the water quality of the cover system of the storage site Francop in Hamburg. Two lysimeters (500 m2 each) were constructed.

During the first dry year after the construction of the lysimeters discharge rates <0.05 mm/d were measured below the sludge barrier. The hydraulic gradients indicate downward water movement in the sludge barrier during the summer and the winter of 1996. The chemical composition of the discharge below the barrier is typical for sludge pore water. An increase of the discharge above the sludge barrier neither led to an increase of discharges nor to changes in the concentration of the water compounds below the barrier. We assume that up to now there is no preferential flow through the sludge barrier. The cover system including the sludge barrier performs very well. The monitoring of the lysimeters is continued.
Strategies for management of contaminated sediments within the meuse river-system
Authors: Hakstege A. L. , Heynen J. J. M. , Eenhoorn J. K. , Versteeg H. P.
Published: May 2018

The sediments in the Meuse valley are contaminated on a large scale by diffuse sources. The project ‘Maaswerken’ aims at the enlargement of the discharge capacity of the river Meuse. In the realization of the project, a full-scale clean-up operation would not be realistic and not effective because of recontamination and the enormous scale and costs involved. The concept of dynamic soil management offers a solution to this problem. This approach to remediation implies putting back contaminated sediments of indigenous quality within the river system. Preconditions are determined by risk assessment and local conditions. The first aim is improvement of the environmental quality of the river system. Other objectives such as the development of natural areas, the mitigation of geohydrological effects and the exploitation of sand and gravel can be realized by several forms of beneficial use of contaminated sediments. Dynamic soil management is expected to be a pragmatic and cost-effective solution for the problem of contaminated sediments.
Integration of sediment cleanup, waterfront redevelopment, and habitat improvements through comprehensive port planning
Authors: Michelsen Teresa C.
Published: May 2018

Ports and industrial waterfronts today face complex problems associated with environmental contamination and habitat loss that affect the ability of local governments to plan and carry out dredging and waterfront development projects. In the USA, separate regulatory programs exist to address source control, cleanup of contaminated sediments, navigational dredging projects, habitat restoration, and shoreline development projects, each with its own set of agencies, permits, and regulatory requirements. In some areas, these overlapping and often conflicting requirements and interests have led to extreme difficulties in completing port development and cleanup projects, even when these projects could have substantial benefits to the environment. This paper presents a shift in regulatory approach toward in-water projects currently being tested by the Department of Ecology and other federal, state, and local agencies in Washington State. Three projects are described that provide regulatory streamlining in exchange for integration of cleanup and habitat restoration needs into Port navigation and waterfront redevelopment projects. In addition to providing significant benefits to both navigation/commerce and the environment, substantial cost savings can be realized in comparison to traditional approaches to these projects.
Chemical description of extracellular polymers: implication on activated sludge floc structure
Authors: Dignac M.-F. , Urbain V. , Rybacki D. , Bruchet A. , Snidaro D. , Scribe P.
Published: May 2018

Activated sludge extracellular polymers (ECP) were extracted either by sonication or a combination of sonication and cation exchange resin treatment (CER). The chemical composition of the aqueous extract was investigated by chromatographic analysis of amino acids and sugars after hydrolysis. Up to 70 to 80% of the total organic carbon (TOC) of ECP was characterized. Proteins were found to be the major constituent of ECP, which was confirmed by pyrolysis/GC/MS analysis. Sugar and protein analysis led to complementary information both on the origin of extracellular material and on sludge floc structure. The monosaccharide composition in ECP and sludge allowed the proposal of different origins for extracellular polysaccharides. The predominance of proteins in ECP underlined their key role in the floc structure, and led to hypotheses on their origin. Proteins were better extracted than sugars when the CER extraction was combined with sonication. This supposed that proteins are more involved than sugars in electrostatic bonds with multivalent cations. Electrostatic bonds were found to be uniformly distributed in the floc and closely combined with hydrophobic bonds. About 25% of ECP amino acids were negatively charged and 24% exhibited hydrophobic properties, highlighting the specific role of proteins in the floc structure.
Biomass yield reduction: is biochemical manipulation possible without affecting activated sludge process efficiency?
Authors: Mayhew Maxine , Stephenson Tom
Published: May 2018

The emphasis for operation of the activated sludge process has switched from the volume of wastewater turnover and effluent quality to minimisation of biomass produced. Attempts including extended aeration, promotion of bacterial predation by higher organisms and increasing process temperature have been successful in lowering yield. These all involve increased operating costs and capital works, whereas the process of chemical uncoupling may be cheaper. After initial chemical screening 2,4 dinitrophenol (2,4 DNP) was continuously dosed in an activated sludge simulation (31 working volume, 5.55h HRT). Effect on process efficiency was monitored by measuring BOD removal and biomass production by MLSS. After 7 weeks of chemical treatment the mean yield coefficient of the treated simulation (Y=0.30) was significantly lower than that of the control (Y=0.42). BOD removal from treated and control samples was comparable and not significantly different.
Disintegration of sewage sludges and influence on anaerobic digestion
Authors: Müller J. , Lehne G. , Schwedes J. , Battenberg S. , Näveke R. , Kopp J. , Dichtl N. , Scheminski A. , Krull R. , Hempel D. C.
Published: May 2018

The improvement of anaerobic digestion was investigated in an interdisciplinary research group. Using four different methods of mechanical cell disintegration the influence of the degree of disintegration and the digestion parameters on the performance of the anaerobic process was investigated. Analytical methods to describe the degree of cell-disruption had to be developed. The best results were obtained using a stirred ball mill and a high-pressure homogenizer. As a result of disintegration the degradation is accelerated and the digestion time can be reduced, especially when using immobilized micro-organisms. The treatment of digested sludge by ozonization respectively by mechanical disintegration led to an improved biodegradability of residual organic compounds. In a following second anaerobic process the treated sludge reached an even higher degree of degradation. On the other hand the disruption of the particle structure leads to an increase in polymer-demand and no improvement in dewatering results. Sludge water, returned to the aeration tanks, is slightly more polluted, especially the concentration of ammonia increases because of the better anaerobic digestion.
Growth requirements of thermophilic aerobic microorganisms in mixed cultures for the treatment of strong wastes
Authors: Sürücü G.
Published: May 2018

The nutritional and temperature requirements of a naturally occurring mixed culture of thermophilic microorganisms were studied. Investigations concerning the effect of temperature on the growth characteristics of the mixed culture showed that the rate of growth was highest between 55 and 58°C. Furthermore, it was found that the minimal nutritional requirements for maximum growth of these microorganisms included methionine, magnesium, calcium, and the necessary carbon, nitrogen and phosphorus sources. It was shown that a mixed culture was nutritionally less fastidious than the pure cultures of individual organisms isolated from the mixed culture; this observation illustrated the possibility of symbiotic growth of thermophilic microorganisms insofar as meeting their individual nutritional requirements.
Anaerobic treatment of proteinaceous wastewater under mesophilic and thermophilic conditions
Authors: Fang H. H. P. , Chung D. Wai-Chung
Published: May 2018

Experiments were conducted in two 2.8 liter UASB (upflow anaerobic sludge blanket) reactors treating proteinaceous wastewaters at 37° and 55°C with 9 hours of hydraulic retention. Results showed that the mesophilic reactor consistently removed 83.5-85.1% of COD (chemical oxygen demand) at loading rates ranging 8-22 g COD l−1 d−1 (corresponding to 3000-8250 mg l−1 of proteinaceous COD in wastewater), whereas the thermophilic reactor removed only 68.5-82.7%. At 32 g COD l−1 d−1 (i.e. 12000 mg COD l−1), the removal efficiencies were lowered to 75.7% in the mesophilic reactor and 65.1% in the thermophilic reactor. At 42 g COD l−1 d−1, severe sludge washout occurred in the mesophilic reactor; at the same loading rate, the thermophilic reactor removed only 53.8% of COD even though sludge washout was under control. The degradation rate in the both reactors was limited by the initial hydrolysis of proteins. However, batch tests showed that thermophilic sludge had slightly higher methanogenic activities than mesophilic sludge in treating proteins and intermediate acids, except propionate. The sludge yields in mesophilic and thermophilic reactors were 0.066 and 0.099 g VSS g COD−1, respectively. Observations by scanning electron microscopy indicated that both types of sludge granules were of irregular shape. There was little noticeable difference between the two granules; both had neither a layered microstructure nor a predominant bacterial species.
Anaerobic treatment of textile size effluent
Authors: Sacks J. , Buckley C. A.
Published: May 2018

This investigation focused on the KwaZulu-Natal province, where a number of under-utilised and under-performing anaerobic digesters were identified. The aim of the study was to assess the potential for treatment of high-strength or toxic organic agro-industrial effluents in the available capacity. The anaerobic digestion of a textile size effluent was investigated. Inhibitory components and concentrations of the solution were identified. The size solution was degraded anaerobically but could cause overloading of a digester at high concentrations. The performance efficiency of the anaerobic digesters at the Umbilo Sewage Purification Works was evaluated. The digesters were operating efficiently and had available hydraulic and organic capacities. This investigation confirmed the potential for the treatment of high-strength organic effluents in the available anaerobic digester capacity.
Treatment of organic chlorine in pulping effluents by activated sludge
Authors: Demirbas G. (Goktayoglu) , Gokcay C. F. , Dilek F. B.
Published: May 2018

A model activated sludge (AS) plant was fed by pulping effluents from a straw and reed processing paper works. The model was initially operated to simulate a dedicated treatment plant by continuously receiving chlorinated effluents from the pulp bleachery. In this simulation cycle the model activated sludge was seeded only once during start-up and did not receive any domestic sewage after that. A carbon source was added in some of the experiments to bring up the organic content. In the second simulation cycle the pulping effluent was co-treated with municipal sewage. In this case the activated sludge unit was being continuously dosed by microorganisms and the organics present in the sewage. A higher organic chlorine (AOX) removal was obtained at shorter SRTs in the co-treatment AS. High AOX removal was achieved at longer SRTs in the dedicated, once-seeded AS. The AOX removal mechanism was mineralization in both cycles.
Characterisation of urban runoff pollution in Paris
Authors: Gromaire-Mertz M. C. , Garnaud S. , Gonzalez A. , Chebbo G.
Published: May 2018

Runoff was collected from 4 roofs, 3 courtyards and 6 streets on an experimental catchment in central Paris, and analysed for SS, VSS, COD, BOD5, hydrocarbons, heavy metals both as regards dissolved and particle fractions. Whereas street runoff showed important SS, COD and hydrocarbon loads, roof runoff was noticeable for its high concentration of heavy metals. These concentrations in comparison with water quality standards enhance the importance of runoff pollution. The use of sample settling for runoff treatment is discussed on the basis of data concerning the distribution between dissolved and particle bound pollution loads, along with settling velocity measurements. Runoff particles were found to be highly contaminated with heavy metals and hydrocarbons, which raised the problem of sludge disposal.
Three examples of temporary stormwater catchments in dense urban areas: a sustainable development approach
Authors: Piel C. , Perez I. , Maytraud T.
Published: May 2018

The Seine Saint-Denis County Council carried out a study involving 200 water storage installations within its jurisdiction. The results showed that many of the basins were inadequate in such a dense urban area. The main problems were the following: difficulty of access, insufficient maintenance and poor integration into the urban landscape. To remedy the situation, the DEA launched research and information projects aiming to foster the development of techniques which would be better suited to dense urban areas, looking especially at catchments in parking lots, squares and other urban spaces. Three examples follow, illustrating the high potential of these techniques as well as the concrete or theoretical obstacles they may encounter. On a broader level, the examples demonstrate that these techniques are part and parcel of a “sustainable development” approach.
Performance, environmental and cost comparisons of onsite detention (OSD) and onsite retention (OSR) in re-developed residential catchments
Authors: Scott Peter , Santos Ruben , Argue John R.
Published: May 2018

On-site detention (OSD) of storm runoff decreases catchment peak flows through the routing effect of temporary storage; on-site retention (OSR) achieves the same objective by abstracting part of the urban flood wave and passing the retained water to disposal on site. The investigation explored both strategies applied to a set of hypothetical present/re-developed urban catchments ranging in size from 14 ha to 210 ha. Comparisons were made on the basis of site storage required (SSR) to achieve the same global peak flow reductions, environmental aspects and cost. OSR practice was shown to out-perform OSD generally in medium-large catchments with respect to SSR and, hence, cost. The retention option also has clear environmental benefits that fall beyond the scope normally ascribed to OSD practice. The paper cautions against use of OSR in unsuitable circumstances.
A new litter trap for urban drainage systems
Authors: Phillips D. I.
Published: May 2018

Litter is generated in shopping areas and is washed or blown into stormwater drainage systems. These convey the litter to open water bodies leading to the accumulation of non-biodegradable litter on the banks and beaches of urban waterways and bay foreshores. The increasing public awareness of the problem prompted the State Government of Victoria to provide funding to develop an innovative patented litter trap known as the In-line Litter Separator (ILLS). The ILLS is retrofitted to the drainage system downstream of shopping areas and removes litter and other pollutants from the passing stormwater. In a two-year development program, ten prototypes were installed and tested in the Melbourne and metropolitan area. The results were so successful that the ILLS is now manufactured in Australia and overseas under license from Swinburne University. This paper presents the performance criteria, the design concepts, the outcomes of laboratory and hydrologic modelling and the analyses of prototype test results that led to the commercial production of the ILLS.
Irrigation water quality and farm management decisions
Authors: Kuchanwar O. D. , Kale C. K. , Deshpande V. P. , Dharmadhikari D. M.
Published: May 2018

The quantity and quality of water available for irrigation is variable from place to place in India. There are regions where the farmers have no access to any surface water body, nor do they have any ground water source yielding water of acceptable quality for irrigation. In some of the coastal areas, neither surface water nor ground water of acceptable quality may be available. In such areas, setting up an industry and transporting good quality surface water from long distances to the site may be useful for farmers in the adjacent areas; the treated wastewater from the industry may constitute a dependable source for irrigation. This paper gives a brief account of some of these peculiar situations.

Whatever the situation, it is necessary that the water used for irrigation is of an acceptable quality for the crop concerned, growing on the soil of the site. For a given crop, during its growth cycle, it is essential that the concentration of the soil solution around the root zone with regard to dissolved solids and specific ions, does not exceed the tolerance limit for the crop. The tolerance limits for various crops are different, representing 8- to 10-fold variation. Soil type and meteorological parameters of the site, for a given irrigation scheduling, also govern as to what will be the maximum soil solution concentration during the growth cycle of the crop. For a given crop, given soil and prevailing climate, the quality of irrigation water and management ultimately determine this maximum level. At a given place, the type of soil and meteorological parameters cannot be managed by human beings. The farmer can, however, exercise some control on the quality of irrigation water by selecting an appropriate source or changing the quality by dilution and/or he can make certain changes in the agronomic control and crop selection. In this paper, an attempt has been made to describe a few more important irrigation water quality criteria which will be easy for the users to follow and arrive at a decision on management, agronomic controls including crop selection, and search for an alternative water source of acceptable quality. This paper also describes a few cases of application of the irrigation water quality criteria in helping to make relevant decisions.
Enterovirus detection from wastewater by RT-PCR and cell culture
Authors: Gantzer C. , Senouci S. , Maul A. , Lévi Y. , Schwartzbrod L.
Published: May 2018

This study was carried out first to determine if virus concentration by adsorption to glass wool was suitable for the detection of enterovirus genomes by seminested RT-PCR in treated wastewater, and second to compare the presence of infectious enteroviruses and enterovirus genomes. The experiments were performed on 57 treated wastewater samples from two wastewater treatment plants which use different processes. The water samples were analysed directly and after concentration on glass wool. Concerning the effect of a concentration step on glass wool, the results show that after concentration, the number of positive samples increases significantly for both infectious enteroviruses (17 vs 0) and enterovirus genomes (37 vs 9).

Concerning the comparison of the presence of infectious enteroviruses and enterovirus genomes, it appears for all the samples analysed that the number of positive samples for enterovirus genomes is significantly higher than those for infectious enteroviruses (37 vs 17). Therefore, the presence of enterovirus genomes cannot be considered to be an indicator of the presence of infectious enteroviruses, strictly speaking, but only an indicator of more or less recent viral contamination. However, 3 samples containing infectious enteroviruses are negative by seminested RT-PCR. These false negative results can be explained by the presence of substances that inhibit seminested RT-PCR reactions.
Sustainable use of poor quality water with proper scheduling of irrigation and nitrogen levels for a rice crop
Authors: Sharma D. K. , Sharma D. R.
Published: May 2018

Over-exploitation of groundwaters to meet the water requirements for rice-wheat systems is causing both a fall in groundwater levels and their quality deterioration in semi-arid parts of India. Adoption of rice-wheat cropping systems by the farmers using poor quality (sodic) waters for irrigation may adversely affect soil health and thereby reduce crop yield. Adoption of an irrigation schedule coupled with optimum nitrogen doses can be advantageous for sustaining yields of rice in these areas. Strategies for optimum use of these inputs has to be based on the knowledge of soil-water-nutrient-plant interactions evolved through field studies. In order to develop such relations, studies involving several combinations of irrigation levels and nitrogen doses were conducted on rice crops at Kaithal (India), and their effect on biomass, yield, water and nitrogen use efficiency (NUE) were studied during 1993 and 1994. Irrigation schedules were based on the period of submergence ranging from 0 to 6 days. The nitrogen doses varied from 0 to 180 kg ha−1. Both irrigation and nitrogen had a positive effect on yield, which increased from 1729 kg ha−1 (continuous submergence without fertilizer) to 4522 kg ha−1 (irrigation at 3 days disappearance of water with 180 kg N ha−1. At 60 kg N ha−1, NUE varied from 35.4 to 40.9 kg ha−1 grain per kg of N. Further increase in the dose of N upto 180 kg ha−1 however resulted in a decline in NUE. Nitrogen and irrigation had a positive influence on applied water efficiency (AWE). Under continuous submerged conditions, the beneficial effect of N on AWE was observed only up to 120 kg ha−1. But at lower levels of irrigation (3 and 6 days disappearance of water), these effects continued even up to 180 kg ha−1. The results of this study indicated that there is a possibility of using the sodic water (up to residual sodium carbonate [RSC] of 8 meq/l) for growing rice provided the crop is irrigated with an appropriate irrigation scheduling with the higher dose of N under conditions of > 50 cm monsoon rainfall.
New strategies in stormwater-meltwater management in the city of Bergen, Norway
Authors: Thorolfsson Sveinn T.
Published: May 2018

In the City of Bergen, Norway, extensive measures against point pollution sources are now to be implemented and to be finished before the end of year 2000, improving the receiving water conditions. Local politicians and public opinion support high standards of receiving water, even higher than the national level. Future improvements in the receiving water quality is planned through different measures aimed at reducing stormwater-meltwater runoff which causes surface pollution wash-off and combined sewer overflows. The city is now presenting a master plan for the water environment and urban runoff management. One of the main issues of the plan is measures for stormwater-meltwater quantity and quality problems. This paper describes the background for the plan and the reasons for introducing new strategies in integrated stormwater-meltwater management. The non-polluted stormwater-meltwater is to be handled near the source by percolation and/or detention. The polluted stormwater-meltwater is to be collected and conveyed to an appropriate site for treatment and discharge. The alternative drainage system named the Sandsli-system is described.
A Review of the Design and Performance of Vertical-flow and Hybrid Reed Bed Treatment Systems
Authors: Cooper Paul
Published: May 2018

The paper reviews the different options for the combination of vertical- and horizontal-flow beds used in hybrid reed bed/wetland systems. The design and performance of these systems are briefly described. The importance of the oxygen transfer capacity of the different arrangements to their performance and their size is discussed. Alternative methods for denitrification are briefly described.
Performance of a Constructed Wetland Leachate Treatment System at the Chunchula Landfill, Mobile County, Alabama
Authors: Martin Craig D. , Johnson Keith D. , Moshiri Gerald A.
Published: May 2018

Leachate poses a number of environmental problems. This is due primarily to the extreme variability of sources of this material, and, therefore, the heterogeneity of its composition. Operating and closed landfills generate leachate whose quality and quantity depend on how the landfill was constructed, operated and ultimately closed. Currently, a number of options exist for the containment and treatment of this type of wastewater. The methodology presented here utilizes surface-flow constructed wetlands for treatment and disposal of leachate and leachate-contaminated groundwater at the Chunchula, Alabama closed landfill. The final goal was to provide effluent water quality standards to conform to Federal National Pollution Discharge Elimination System (NPDES) guidelines.
The Microbiology Associated with Glycol Removal in Constructed Wetlands
Authors: Chong S. , Garelick H. , Revitt D. M. , Shutes R. B. E. , Worrall P. , Brewer D.
Published: May 2018

During the winter months, the application of large quantities of glycol based anti- and de-icers to aircraft and runways poses a serious threat to receiving waters because of their toxicity and BOD effect. The orthodox approach has been to store runoff waters in aerated lagoons before discharge to receiving waters or to sewage treatment works. In the development of a pollution control strategy for Heathrow Airport Ltd. (HAL), a combination of alternative methods for treatment are being considered, and amongst these is the use of constructed wetlands on a pilot scale. Results from this study indicate that most constructed wetland plants and substrate micro-organism populations throughout the beds are not adversely affected by airport runoff or exposure to shock-loads of glycols at initial total concentrations of 1180mg/1 and 632mg/1 in the subsurface and surface flow reedbeds respectively. Apart from Typha spp, the aquatic macrophytes have adapted well to the exposure to airport runoff. Glycol removal efficiencies have improved as the beds have matured, and average removal efficiencies of 78% for the sub-surface system and 54% for the surface system have been recorded. Complimentary monitoring of substrate micro-organism populations prior to and after glycol dosings have shown that aerobic microbial groups of bacteria, fungi and actinomyctes, are present in higher numbers (105−107 CFU/g substrate dry weight) than their anaerobic counterparts (103−105 CFU/g substrate dry weight). In the laboratory, studies have shown fungi and bacteria to be most tolerant of glycol, with several strains able to utilise these compounds.
Kinetics of Fecal Coliform Removal in Constructed Wetlands
Authors: Khatiwada N. R. , Polprasert C.
Published: May 2018

Major mechanisms influencing the removal of fecal microorganisms in constructed wetlands treating sewage in tropical regions include the effects of temperature, solar radiation, sedimentation, adsorption and filtration. This study aims to develop a model describing the kinetics of fecal coliform removal in free-water-surface (FWS) constructed wetlands. Separate model equations were proposed for removal rate coefficients for each of the major removal mechanisms. The model parameters were assessed from both literature and the performance data of laboratory-scale FWS constructed wetland units planted with cattails (Typha angustifolia). The model parameters and the kinetic model were validated with experimental data of two pilot-scale constructed wetlands. Statistical analyses of the calculated and observed performance data of the pilot-scale units revealed good correlation and were without significant practical difference, suggesting the kinetic model was feasible.
Suitability of a Treatment Wetland for Dairy Wastewaters
Authors: Geary P. M. , Moore J. A.
Published: May 2018

A treatment wetland was constructed as part of a waste management system for dairy parlour waters and the performance of the wetland in reducing organic matter and nutrients monitored for a two-year period. The wetland was designed for a herd size of 110 with a detention time of approximately 10-14 days. Hydraulic loads to the wetland averaged 25 mm/day, although there were wide fluctuations due to rainfall and water use within the dairy. Average mass loadings to the wetland were 5.6 g/m2/d for Biochemical Oxygen Demand, 2.6 g/m2/d for Organic Nitrogen, 3.2 g/m2/d for Ammonia and 1.5 g/m2/d for Total Phosphorus.

Monitoring results from the system indicated that significant BOD reductions were achieved, while Nitrogen and Phosphorus removals were variable but smaller. Calculated mean monthly pollutant reductions due to the treatment wetland were 61% for BOD, 43% for Organic Nitrogen, 26% for NH3 and 28% for TP. The wetland received high hydraulic and pollutant loads and appeared to act as a sink for the nutrients which were removed. At this scale it did not appear to be suitable as a treatment option for significantly reducing nutrients in this type of agricultural waste.
Design and Performance of Experimental Constructed Wetlands in Uganda, Planted with Cyperus Papyrus and Phragmites Mauritianus
Authors: Okurut T. O. , Rijs G. B. J. , van Bruggen J. J. A.
Published: May 2018

The viability of the use of constructed wetlands planted with indigenous Cyperus papyrus and Phragmites mauritianus plants for the purification of pre-settled municipal wastewater in tropical environments was investigated in concrete lined constructed wetlands for a period of 11 months. BOD and total suspended solids concentrations in the effluents from both systems were below 20 mg/l and 25 mg/l, respectively. In the C. papyrus systems, the removal rates for COD, NH4+ and o-PO4− averaged to 3.75, 1.01 and 0.05 (g/m2.day), respectively. In P. mauritianus units, the rates were 1.52, 0.97 and 0.068 (g/m2.day), respectively. A high degree of faecal coliform removal was attained at longer retention times in the two systems.
Calibrating simple models for mixing and flow propagation in waste water treatment plants
Authors: De Clercq Bob , Coen Filip , Vanderhaegen Bart , Vanrolleghem Peter A.
Published: May 2018

Mathematical models are useful tools in the prediction of system responses to operational changes in waste water treatment plants (WWTPs). The tanks-in-series model is one of the widespread hydraulic models in waste water treatment. This study shows the applicability of the mentioned model. Next to the mixing of substrate in a conventional activated sludge system, an oxidation ditch and a trickling filter, also the flow propagation in a waste water treatment plant was modelled. These different full-scale examples taken from waste water treatment demonstrate the relative ease of model configuration and calibration. Difficulties like experimental design, modelling the diffusion in biofilms and transients in flow rate were encountered.
Fuzzy control of aeration in an activated sludge wastewater treatment plant: design, simulation and evaluation
Authors: Kalker T. J. J. , van Goor C. P. , Roeleveld P. J. , Ruland M. F. , Babuška R.
Published: May 2018

Fuzzy logic can in several ways be applied to improve the control of the activated sludge system. In the present study, two types of fuzzy logic controllers were developed for intermittent aeration control: a low-level fuzzy controller for DO control and a high-level controller for nitrogen removal. A Simulink-SIMBAR model was used to subsequently design and optimise the controller and furthermore to compare various control strategies. The results indicate that the direct fuzzy controller allows for some improvements in comparison with a PI controller. Nevertheless, it is suggested that high-level controllers have more potentials for improving and integrating the control of wastewater treatment. The developed high-level fuzzy controller performs better than two conventional controllers in terms of energy consumption and, at the same time, results in a slightly better effluent quality. Design and tuning were quite straightforward. Since the rule base applied is comprehensive it is expected that in practice the controller will meet with the demands of the operator.