bluuebunny/crossref_metadata_2025 huggingface dataset:
Replacement of secondary clarification by membrane separation - results with plate and hollow fibre modules
Authors: Günder Berthold , Krauth Karlheinz
Published: May 2018

Submerged membrane systems can replace the final clarification step to separate mixed liquor suspended solids (MLSS) from treated wastewater in the activated sludge processes. Mixed liquor suspended solids concentrations as high as 20 g/l can be maintained compared with the typical 3–4 g/l for conventional activated sludge/secondary clarifier systems. This leads to much smaller reactor volumes. In addition, excellent, solid free effluent qualities can be achieved with this process technology. One major challenge, when applying membrane technology to municipal wastewater treatment systems, is handling the flow variations typically encountered by these systems. This paper reports about the parallel investigation of two membrane-systems installed within a 7 m3 and a 9 m3 bioreactor. One membrane system used submerged plate modules (80 m2 membrane surface), the other hollow fibre modules (83.4 m2). The emphasis of this first investigation was the hydraulic performance and elasticity of the membrane systems. At MLSS concentrations of 15 g/l and hydraulic retention times of 6 hours, flux rates of 15 l/m2 h under permanent operation and up to 30 l/m2 h for short periods of time were achieved (standardised to a temperature of 10°C). A stable operation at these rates could be achieved for a full 4 months period without chemical cleaning of the membranes. Future studies will focus on nutrient removal aspects and the energy consumption of the systems.
Effects of synthetic organic chemicals on bacterial death and lysis
Authors: Perez-Padilla G. G. , Grady C. P. L.
Published: May 2018

A technique derived from the tritiated thymidine method was used to characterize the effects of synthetic organic compounds (SOCs) on the specific rate of bacterial death as functions of chemical concentration, the physiological state of the cells, and exposure time to the toxicant. The rate of bacterial death was estimated by following over time the release of radioactive tracer from the DNA of thymidine-requiring (thy−) mutant E. coli cells (ATCC 23820). Results indicate that the lysis rate of unexposed microbial cultures was the same whether or not the cells were growing or had reached the stationary phase. Lysis rates were calculated from exposures to single SOCs: acrylonitrile, ethylene glycol, isophorone, phenol, 2-chloro- and 4-chlorophenol. The concentrations tested were 250, 1000 and 5000 mg COD/l. The major effect observed with stationary-phase cultures was a stimulation of the rate of lysis, whereas a reduction in the rate of lysis was the primary effect observed with growing cells. A physiological interpretation for these opposite effects is provided. The physiological state of the microorganisms influenced the magnitude, intensity and type of effects caused by the presence of synthetic organic compounds.
Microbial Fe(II)-oxidation by nitrate in activated sludge
Authors: Nielsen Jeppe Lund , Nielsen Per Halkjær
Published: May 2018

The oxidation of Fe(II) to Fe(III) by addition of nitrate and nitrite to activated sludge was studied to determine whether the process was biological or chemical (chemodenitrification). It was shown that the process was mainly biological, although the microorganisms involved have not yet been described. Investigations in a full scale treatment plant suggested that the process most likely took place in the anoxic (denitrification) tank. Details of the kinetics and stoichiometry have not yet been determined, but the process may be of significance for keeping Fe(III) oxidized, which is important for P-removal and for floc structure. Furthermore, in some treatment plants, the oxidation may also be of significance for nitrate removal (denitrification).
Analysis of microbial acclimation to refractory chemicals in wastewater using respiratory quinone profiles
Authors: Hu Hong-Ying , Nozawa Mamie , Fujie Koichi , Makabe Tsuyoshi , Urano Kohei
Published: May 2018

The effects of initial microbial concentration and the coexistence of biodegradable substrates on the acclimation of microbes to acrylonitrile (AN) was investigated in an aerobic submerged biofilter using respiratory quinone profiles. The acclimation of microbes to AN was accelerated by increased initial microbial concentrations in the biofilter and by the coexistence of glucose and peptone in the influent. The change in quinone profiles of microbial films during the course of acclimation suggested that Brevibacterium sp., Pseudomonas aeruginosa and Corynebacterium sp. contributed to the degradation of AN in the aerobic biofilter.
Determination of the microbial diversity of anaerobic-aerobic activated sludge by a novel molecular biological technique
Authors: Liu Wen-Tso , Marsh Terence L. , Forney Larry J.
Published: May 2018

Sequential anaerobic-aerobic batch reactors were maintained on acetate/peptone and two different P/total organic carbon ratios that select for microbial communities enriched for either glycogen-accumulating organisms (GAO) or polyphosphate-accumulating organism (PAO). The community profiles of the eubacterial population and gram-positive high G-C bacteria (HGC) were characterized and compared by determining the terminal restriction fragment length polymorphisms (T-RFLP) of 16S rDNA. The HhaI+RsaI digested 5′ T-RFLP patterns of the eubacterial 16S rDNA amplified from the GAO- and PAO-enriched communities were made up with 12 and 14 rank-abundant fragments (i.e., ribotypes), respectively. Among those ribotypes detected in the GAO-enriched community, only seven were found in the PAO-enriched community. The HGC group could only account for no more than 6% and 17% of the eubacterial 16S rDNA amplified from the GAO- and PAO-enriched communities, respectively. Within the HGC community, at least 16 and 10 rank-abundant ribotypes were observed in the MspI digested T-RFLP patterns of GAO- and PAO-enriched communities, respectively. Among those HGC ribotypes observed in both communities, only five were in common. These indicate that the enrichment processes leading to the establishment of GAO- and PAO-specific communities caused the dramatic difference and complexity in the microbial population.
Combining fluorescent in situ hybridization (fish) with cultivation and mathematical modeling to study population structure and function of ammonia-oxidizing bacteria in activated sludge
Authors: Wagner Michael , Noguera Daniel R. , Juretschko Stefan , Rath Gabriele , Koops Hans-Peter , Schleifer Karl-Heinz
Published: May 2018

16S rRNA-targeted oligonucleotide probes for phylogenetically defined groups of autotrophic ammonia-oxidizing bacteria were used for analyzing the natural diversity of nitrifiers in an industrial sewage treatment plant receiving sewage with high ammonia concentrations. In this facility discontinuous aeration is used to allow for complete nitrification and denitrification. In situ hybridization revealed a yet undescribed diversity of ammonia oxidizers occurring in the plant. Surprisingly, the majority of the ammonia oxidizers were detected with probe combinations which indicate a close affiliation of these cells with Nitrosococcus mobilis. In addition, low numbers of ammonia-oxidizers related to the Nitrosomonas europaea - Nitrosomonas eutropha cluster were present. Interestingly, we also observed hybridization patterns which suggested the occurrence of a novel population of ammonia oxidizers. Confocal laser scanning microscopy revealed that all specifically stained ammonia oxidizers were clustered in microcolonies formed by rod-shaped bacteria. Combination of FISH and mathematical modeling was used to investigate diffusion limitation of ammonia and O2 within these aggregates. Model simulations suggest that mass transfer limitations inside the clusters are not as significant as the substrate limitations due to the activity of surrounding heterotrophic bacteria. To learn more about the ammonia-oxidizers of the industrial plant, we enriched and isolated ammonia-oxidizing bacteria from the activated sludge by combining classical cultivation techniques and FISH. Monitoring the isolates with the nested probe set allowed us to specifically identify those ammonia oxidizers which were found in situ to be numerically dominant. The phylogenetic relationship of these isolates determined by comparative 16S rDNA sequence analysis confirmed the affiliation suggested by FISH.
Horizontal transfer of bacterial heavy metal resistance genes and its applications in activated sludge systems
Authors: Dong Qinghan , Springeal Dirk , Schoeters Jef , Nuyts Gust , Mergeay Max , Diels Ludo
Published: May 2018

The bacterial nickel (Ni) resistance determinant ncc-nre of Alcaligenes 31A strain cloned to an IncQ broad-host-range plasmid pKT240 gave rise to pMOL222. The plasmid was subsequently mobilized into various Eubacteria and found to confer an increased Ni resistance on these recipients. An increase of Ni resistance was also observed after the transfer of pMOL222 into activated sludge bacteria by plate mating. The dissemination of pMOL222 into an activated sludge pilot stabilized the system during a heavy metal shock loading with 0.25 mM Ni.
Distribution of absorbance in the visible spectrum related to molecular size fractions in secondary and tertiary municipal-textile effluent
Authors: Rozzi A. , Malpei F. , Colli S. , Uberti M.
Published: May 2018

Distribution of absorbance into the visible spectrum was investigated as a function of the molecular size in the following streams: the secondary effluent from a denitrification/nitrification activated sludge treatment plant (80% as COD load and 70% as hydraulic load from textile industries) and the intermediate and final effluents of a pilot-scale advanced wastewater treatment (AWT) fed on the secondary effluent, consisting of clariflocculation (FPS) and of granular activated carbon adsorption (GAC). Correlations with the TOC distribution determined in a previous research were also investigated. The TOC distribution and absorption fingerprints as a function of the molecular “cuts” were found to be quite different: TOC was made of small fractions up to the last “cut” for the three sampled streams (influent, effluent FPS and effluent GAC). The % absorbance distribution is much less homogeneous, and correlation between % TOC and % absorbance seem to be very poor which confirms that photometric analysis in the visible spectrum is unsuitable to monitor residual pollution in textile effluents.
Biological sulfate removal in an acidogenic bioreactor with an ultrafiltration membrane system
Authors: Mizuno O. , Takagi H. , Noike T.
Published: May 2018

The biological sulfate removal in the acidogenic bioreactor with an ultrafiltration membrane system was investigated at 35°C. Sucrose was used as the sole organic substrate. The sulfate concentration in the substrate ranged from 0 to 600mgS·1−1. The chemostat reactor was operated to compare with the membrane bioreactor. The fouling phenomenon caused by FeS precipitate was observed at higher concentration of sulfate. However, it was possible to continuously operate the membrane bioreactor by cleaning the membrane. The efficiency of sulfate removal by sulfate reduction reached about 100% in the membrane bioreactor, and 55 to 87% of sulfide was removed from the permeate by the membrane filtration. The composition of the metabolite was remarkably changed by the change in sulfate concentration. When the sulfate concentration increased, acetate and 2-proponol significantly increased while n-butyrate and 3-pentanol decreased. The sulfate-reducing bacteria play the role as acetogenic bacteria consuming volatile fatty acids and alcohols as electron donors under sulfate-rich conditions. The results show that the acidogenesis and sulfate reduction simultaneously proceed in the membrane bioreactor.
Identification and quantification of Gordona amarae strains in activated sludge systems using comparative rRNA sequence analysis and phylogenetic hybridization probes
Authors: de los Reyes Ma. Fiorella , de los Reyes Francis L. , Hernandez Mark , Raskin Lutgarde
Published: May 2018

Small subunit (SSU) ribosomal RNA (rRNA) genes of four Gordona (Nocardia) amarae strains were sequenced and compared to the sequence of the G. amarae type strain obtained from the Ribosomal Database Project (RDP). Comparative sequence analysis showed that the five strains represent two lines of evolutionary descent: Group 1 consists of strains NM23 and ASAC1 and Group 2 contains strains SE-6, SE102, and ASF3. To determine the abundance of G. amarae in activated sludge systems, we designed three oligonucleotide probes: a species-specific probe for G. amarae, a probe specific for Group 1 and a probe targeting Group 2. The probes were characterized by performing dissociation temperature and specificity studies. Using these probes, two other strains, strains SE-149B and RBI, also were found to be part of Group 1. We used these probes along with previously designed probes in membrane hybridizations to determine the abundance of G. amarae, Group 1, Group 2, Bacteria, Mycobacterium complex, and Gordona in samples from foaming episodes. We demonstrated that the Mycobacterium complex, the genus Gordona, and G. amarae strains were present in significantly greater concentrations in activated sludge foam than in mixed liquor.
A flux-based stoichiometric model of enhanced biological phosphorus removal metabolism
Authors: Pramanik J. , Trelstad P. L. , Keasling J. D.
Published: May 2018

Enhanced biological phosphorus removal (EBPR) in wastewater treatment involves metabolic cycling through the biopolymers polyphosphate (polyP), polyhydroxybutyrate (PHB), and glycogen. This cycling is induced through treatment systems that alternate between carbon-rich anaerobic and carbon-poor aerobic reactor basins. While the appearance and disappearance of these biopolymers has been documented, the intracellular pressures that regulate their synthesis and degradation are not well understood. Current models of the EBPR process have examined a limited number of metabolic pathways that are frequently lumped into an even smaller number of “reactions.” This work, on the other hand, uses a stoichiometric model that contains a complete set of the pathways involved in bacterial biomass synthesis and energy production to examine EBPR metabolism. Using the stoichiometric model we were able to analyze the role of EBPR metabolism within the larger context of total cellular metabolism, as well as predict the flux distribution of carbon and energy fluxes throughout the total reaction network. The model was able to predict the consumption of PHB, the degradation of polyP, the uptake of acetate and the release of Pi. It demonstrated the relationship between acetate uptake and Pi release, and the effect of pH on this relationship. The model also allowed analysis of growth metabolism with respect to EBPR.
Transport of contaminants along the Seattle waterfront: effects of vessel traffic and waterfront construction activities
Authors: Michelsen Teresa C. , Boatman Charles D. , Norton Dale , Ebbesmeyer Curtis C. , Francisco Michael D.
Published: May 2018

Cleanup of contaminated sediments along the Seattle waterfront is complicated by uncertainty regarding sources of contamination and the interrelationship between point sources, non-point sources, vessel traffic, construction projects, and resuspension. The results of field studies are presented that address the potential for recontamination of sediments following proposed cleanup projects, the sources of contamination and their relative magnitudes, and the natural and anthropogenic processes that affect transport of contaminated sediments along the waterfront. The primary factors affecting the success of cleanup projects along the Seattle waterfront are identified as resuspension of contaminated sediments by propellor wash and construction activities, and subsequent transport of the suspended sediments by natural and vessel-induced currents to adjacent areas.
The use of a mathematical model to evaluate mercury accumulation in sediments and recovery time in a coastal lagoon (Ria de Aveiro, Portugal)
Authors: Abreu S. N. , Pereira M. E. , Duarte A. C.
Published: May 2018

The urge of restoration and management of vital ecosystems (mainly those that affect directly human health) has become one of the most requested priorities. Ria de Aveiro (a lagoon on the north-western coast of Portugal) has an important economic role in local and surrounding areas due to its variety of resources. Studies have shown that there is an effective risk of hindering traditional activities due to high levels of mercury. Mercury concentrations in 1985 ranged from 0.7 μg g−1 to 850 μg g−1 in surface sediments and concentrations up to 25 μg g−1 fresh weight in fishes. A mathematical model (ECoS) was used to perform a simulation of mercury accumulation in surface sediments along the most contaminated channel from the beginning of the industrial discharges (in the 50's) until present days and recovery time for a zero mercury discharge from 1995 until 2045. The model shows that the amount of mercury in the surface sediments would decrease exponentially due to both deposition of mercury free particles and ressuspension of less and less contaminated particles. The model estimated levels actually measured along the channel and evaluated that, even after 40 years, mercury concentration would be approximately 50 μg g−1 in the most contaminated section of that channel if the discharges were discontinued now.
Organic halogen, heavy metals and biological activities in pristine and pulp mill recipient lake sediments
Authors: Suominen K. P. , Wittmann C. , Kähkönen M. A. , Salkinoja-Salonen M. S.
Published: May 2018

In order to create a basis for prognosing future intrinsic remediation potential of past pollution by pulping industry, we analyzed biochemical activities and levels of pollution in sediments dated with 210Pb and 137Cs. A small pristine forest lake and a pulp mill recipient area of a large oligotrophic Lake Saimaa were test sites. Sediment concentration of EOX ranged from 40 to 130 μg Cl (g d.w.)−1 in the pristine lake and from 770 to 4700 μg Cl (g d.w.)−1 in the pulp mill recipient area and the C:Cl (w/w) ratio of sediment organic matter ranged from 2000 to 5100 and 42 to 230, respectively. The organic matter in 10 to 20 years old pulp mill recipient sediment was mainly of waste water origin. The activity gradients of β-glucosidase, butyrate-esterase, methane oxidation potential and endogenous respiration from surface to deeper layers were less steep in polluted than in pristine sediment. Methane oxidation potential was 120 μmol CH4d−1 (g C)−1 at the sediment surface of pristine lake sediment and 26 μmol CH4d−1 (g C)−1 at the polluted site, endogenous respiration rates of the surface sediment were 670 and 310 μmol CO2 d−1 (g C)−1, respectively. In the most polluted layer we found a depressed potential for methane oxidation, inhibition of phosphatase and butyrate-lipase activities and moderately increased induction ratio of β-galactosidase to phosphatase in the SOS-Chromotest strain E. coli PQ 37. The results suggest that at the concentrations observed these effects in the sediment were not due to heavy metals.
Consolidation theory applied to the capillary suction time (CST) apparatus
Authors: Huisman M. , van Kesteren W.G.M.
Published: May 2018

The Capillary Suction Time-method was introduced in 1967, and was designed for establishing the dewaterability of sludge samples. The CST-test was developed as an alternative to the more cumbersome filtration tests using vacuum pumps.

Over the years, extensive research has been conducted on models describing the dewatering process in this apparatus. Most of these models have been based on traditional filtration theory, comprising an assumed average cake filtration resistance. An alternative theory which has not been investigated in this respect before is the large-strain consolidation model proposed by Gibson (1967).

When this particular consolidation theory is applied to the CST-apparatus, it can be shown that from measurements with the CST-test, conducted on a series of samples of a certain sludge or soil with different initial void ratios (or water contents), the coefficient of consolidation of the soil can be deduced. The benefits of this approach are multifold. By describing the dewatering of a sludge with the consolidation theory, e.g. in a lagoon, filter press, centrifugal pumps and so forth, the dry matter content can be predicted with respect to time using the coefficient of consolidation found with the CST-test. Also, the influence of polyelectrolytes added to the sludge to improve the dewaterability can be measured quantitatively as an increase of the coefficient of consolidation.
Natural colloid characterization using flow-field-flow-fractionation followed by multi-detector analysis
Authors: Kammer Frank v. d. , Förstner Ulrich
Published: May 2018

A design for a flow-field-flow-fractionation with UV/VIS-, fluorescence- and laser-light-scattering-detectors is presented and tested with extracts from a humus rich horizon of a gleyic podzol. It is tested to show how the system can retrieve relevant information about changes in the constitution of the colloid samples. The main objective is the investigation of colloid alteration during processes provoked by main geochemical driving forces (e.g. pH or ionic strength), in this case changes of redox potential. Therefore fluorescence- and UV/VIS-fractograms are taken at different wavelengths and compared. Particle diameters of natural colloids are calculated from laser-light-scattering data and compared with reference standards.
From characterization of sediment to full scale treatment by wet particle separation
Authors: Pruijn M. F. , van Winden S. C. , Wevers H. H. A. G.
Published: May 2018

Contaminated sediments represent a significant environmental problem in the Netherlands. Dutch policy aims on reusing the sand in the contaminated sediments. The reusable sand can be separated from the sediment by utilizing wet particle separation techniques. The quality and the quantity of the recovered sand product determines whether the application of wet particle separation is economically feasible. Therefore it is important to be able to predict the results of full scale sediment treatment. These predictions can be obtained by thoroughly characterizing the specific contaminated sediment. In the last years several characterization methods have been developed. This paper presents four cases in which the results of the TDG-test and the Fingerprint are compared with results of the full scale treatment of contaminated sediments. The two main factors: sand quality and the quantity of fine grained fraction remaining are well predicted in all four cases. Therefore the conclusion is that both the TDG-test and the Fingerprint are able to predict whether full scale treatment is feasible.
Assessment of sediment and porewater after one year of subaqueous capping of contaminated sediments in Hamilton Harbour, Canada
Authors: Azcue José M. , Zeman Alex J. , Mudroch Alena , Rosa Fernando , Patterson Tim
Published: May 2018

In this manuscript, we present data from a demonstration in situ capping site (100 m × 100 m) in Hamilton Harbour, Lake Ontario, Canada. A layer of clean medium to coarse sand with the average thickness of 35 cm was placed at the site in the summer of 1995. Concentration of Zn, Cr, and Cd in the original sediments reached values over 6000, 300 and 15 μg/g, respectively. The predicted consolidation of the uppermost one meter of sediment was about 14 cm, which was in good agreement with values obtained from comparisons of moisture content values of pre-capping and post-capping cores. A thin layer of fresh moderately contaminated sediments has started to develop on the top of the cap. In general, the concentrations of elements were greater in porewater than in the overlying water, e.g., the concentration of Fe and soluble reactive phosphorus were 1000 times, and those of Mn 100 times greater. There was a significant reduction in the vertical fluxes of all the trace elements after the capping of the contaminated sediments.
Pilot remediation of sediment from the petroleum harbour in Amsterdam
Authors: Hakstege A. L. , van Geldermalsen L. A.
Published: May 2018

The Petroleum harbour project is the third pilot remediation, which was carried out within the framework of POSW (the national development programme for treatment processes of polluted sediments). The main objectives of the pilot remediation are:– to demonstrate the biological treatment of dredged materials on a practical scale;– to gain knowledge and experience for the future remediation of the total Petroleum harbour.

A strict tender procedure was carefully executed in order to select the most effective and ‘state of the art’ biodegradation technology. The selected remediation chain was a combination of ‘standard’ soil treatment technology and newly developed biotechnology. The contaminated sediments were separated by hydrocyclones, then the sand fraction was cleaned by froth flotation, and the fines were treated in a continuous flow reactor consisting of a cascade of 4 bioreactor tanks. A belt press was used for dewatering the fines. Dredging, biotechnological treatment and the effects of the remediation on the environment were monitored in detail. The quality of the treated sand fraction complied with the Dutch standards for re- use and was actually applied in a project of Rijkswaterstaat. Biodegradation resulted in a substantial decrease of the oil and PAH's contents, but due to the lack of breakdown of a few high-molecular PAH's, the quality requirements of the contract were not achieved. For less heavily polluted sediments and soils the applied biotechnology may be more effective. The results of the project show that biodegradation in bioreactors on a large scale is feasible. Furthermore useful information was gathered for the future remediation of the Petroleum harbour. It is concluded that the two main objectives of the project have been attained. Finally some recommendations for the future clean-up of the Petroleum harbour are given.
Morphology, In-Situ characterization with rRNA targetted probes and respiratory quinone profiles of enhanced biological phosphorus removal sludge
Authors: Sudiana I. M. , Mino T. , Satoh H. , Matsuo T.
Published: May 2018

The microbial communities in activated sludge acclimated with either acetate or glucose as the major carbon source under phosphorus limited or rich conditions were investigated morphologically, phylogenetically and chemotaxonomically. The sludge with a minimized polyphosphate content was dominated by tetrad shaped bacteria, which were suspected to be ‘glycogen accumulating bacteria (GAOs) or G bacteria’ The sludge containing high polyphosphate was dominated by cluster forming coccus bacteria. Quinone analyses suggested that all the sludge tested contained various ubiquinones and menaquinones, of which the ubiquinones Q-8 and Q-10 were dominant. Analyses with rRNA targeted probes showed that beta sub class of Proteobacteria was most predominant in all sludges tested. Morphological, phylogenetic and chemotaxonomic investigation all indicated that both high and low P sludges are microbiologically diverse.
Kinetics of biological treatment of phenolic wastewater in three-phase fluidized bed containing biofilm and suspended sludge
Authors: Hirata A. , Noguchi M. , Takeuchi N. , Tsuneda S.
Published: May 2018

Phenolic wastewater was treated in complete mixing type three-phase fluidized bed which contained both biofilm and suspended sludge. By considering the contributions of biofilm and suspended sludge to biodegradation of phenol separately, phenol removal rates with biofilm and with suspended sludge were evaluated both theoretically and experimentally. As a result, biodegradation of phenolic wastewater by biofilm process could be treated as a zero-order reaction. The volumetric biological removal rates with biofilm was proportional to the specific surface area of the biofilm with biodegradation coefficients (K) of 1.25×10−2 kg-PhOH/m2-biofilm/d. At a lower suspended sludge concentration, bioparticle diameter and bioparticle hold-up in the three-phase fluidized bed reactor were decisive factors for the efficiency of phenol treatment, and it was also proved that almost 100 % of phenol removal could be attained at a larger specific biofilm surface area per volumetric phenol loading rate than 80 m2/(kg-PhOH/d) without suspended sludge.
Experimental basis of activated sludge treatment for industrial wastewaters - the state of the art
Authors: Orhon Derin , Taşlı Rüya , Sözen Seval
Published: May 2018

The paper provides a comprehensive coverage of the experimental information required for the activated sludge treatment of industrial wastewaters. Emphasis is placed upon the choice of parameters for organic carbon removal, the value of basic relationships between major parameters, the merit of size distribution for the evaluation of pretreatment, COD fractionation and its implication in system design, major kinetic and stoichiometric coefficients for process modelling. Relevant experimental data related to a wide range of industrial wastewaters compatible with biological treatment are provided.
Long-term experience with biological pretreatment of rendering plant effluent
Authors: Nowak O. , Wandl G. , Svardal K.
Published: May 2018

At an activated sludge plant for biological pretreatment of rendering plant effluent, incomplete nitrification was repeatedly observed, despite low loading and high SRT. It is hypothesised that inadequate dosage of phosphorus leads to nutrient deficiency, although the effluent phosphate concentration was mostly above 1 mg/l. Evaluation of the ‘actual’ autotrophic maximum growth rate μ^A,T revealed a nitrification inhibition of almost 50% under the operational conditions of this plant, whereas the inhibitory effect caused by the wastewater compounds was found to be much lower. Thus, the poor performance of the nitrification process is rather generated in the plant than caused by the wastewater. Another possible reason - besides phosphorus limitation - for incomplete ammonia oxidation may be found in the anaerobic state of the pre-denitrification tank. In sludge samples from this tank, the nitrification rate was substantially reduced in some cases. At elevated temperatures, nitrification and nitrogen removal can be achieved in relatively small reactor volumes. However, several potential problems have to be considered in the operation of such plants.
Recycling of separated pig manure: characterization of maturity and chemical fractionation of elements during composting
Authors: Hsu J.-H. , Lo S.-L.
Published: May 2018

Composting of separated pig manure (SPM) was studied to evaluate criteria indicating compost maturity and to determine the effect of composting on the fractionation of trace elements in SPM compost. Composting was performed in turn piles and the following parameters were measured in 10 samples during 122 days of composting: temperature, C/N ratio, ash content, metal contents, humic substance contents, and fractions (humic acid, fulvic acid, and nonhumic fractions - HA, FA, and NHF, respectively). A sequential extraction scheme was used to partition Cu, Mn, and Zn in SPM compost. The C/N ratio and ash content exhibited a typically high rate of change during the first 33 days and levelled off thereafter. The fresh SPM was enriched with Cu, Mn, and Zn due to feed additives. All metal concentrations increased approximately 2.6-fold in the final compost due to decomposition of organic matter. The HA content increased to a maximum at 80 days, representing the degree of humification and maturity of the compost. During the composting process, the major portions of Cu, Mn, and Zn were found in the organic, oxide, and carbonate fractions, respectively. Metal distributions in different chemical fractions were generally independent of composting age and, thus, respective total metal concentrations in the composts.
Pollution loads and inert COD in the laying chicken industry
Authors: Babuna F. Germirli , Çekyay E. , Eremektar G. , Orhon D.
Published: May 2018

Modern laying chicken plants generate strong wastewaters of limited flow rate, with COD concentrations up around to 10 g l−1, with a soluble portion of 50% and high nitrogen and phosphorus contents. The unit wastewater flow is as low as 0.003-0.005 1 chicken−1 day−1 and the unit organic load is assessed as 0.03 g COD chicken−1 day−1. COD fractionation reveals that the soluble residual portion accounts for 350 mg l−1 in the chicks step and 980 mg l−1 in the laying step for aerobic treatment. When anaerobic treatment is applied this residual fraction is likely to exhibit an increase of around 60 to 80 %. These observations underline the significance and the need of setting effluent limitations attainable by biological treatment, if evidence is presented that they do not pose appreciable environmental problems such as toxicity, colour, etc. This is especially true for laying chicken plant effluents, due to their intermittent mode of generation and their limited volume.
Treatment of bleaching effluent in sequential activated sludge and nitrification systems
Authors: Altınbaş U. , Eroǧlu V. , Öztürk İ.
Published: May 2018

Dechlorination and degradation mechanisms of bleaching effluent were studied in a sequential activated sludge and nitrification reactor. Effect of bleaching effluent on dechlorination performances was examined at various organic loading rates in the system. Released inorganic chlorine (ICl) was increased from 4.5 to 8.5 mg/l in the first stage activated sludge reactor while it was decreased from 10 to 2.5 mg/l in the subsequent nitrification reactor. Removal efficiencies of AOX were found as 15-33% and 5-25% in the activated sludge and the nitrification reactor respectively. TOC removal efficiencies achieved were 67-85% in the activated sludge reactor. The removal efficiency of NH4 achieved 94-98% in the nitrification reactor.
Drinking water supply through reverse osmosis desalination plants in Ramanathapuram district of Tamil Nadu, India
Authors: Ansari M. H. , Kelkar P. S. , Hasan M. Z. , Paramasivan R.
Published: May 2018

The population in Ramanathapuram district of Tamil Nadu State (India) faces potable water scarcity throughout the year in general and acute drinking water problems in lean periods of the year. To mitigate this problem, eleven reverse osmosis (RO) desalination plants were installed in problem villages in the district. General performance of these eleven plants and in-depth evaluation of two plants was undertaken to focus attention on the physico-chemical quality of water at various stages of treatment, present status with respect to operation and management (O & M) financial implications and overall management in a rural situation.

The study indicated that performance of these RO plants was satisfactory in removing high TDS, though the efficiency deteriorated with time. The average utilization of these RO plants since their installation was 46% as compared to the design capacity, mainly due to non-availability of power in rural areas, time lapsed in repairs of pumps, and non-availability of spares. The average capital cost/m3 and O & M cost/m3 of product water from these eleven plants works out to Rs. 27.40 and Rs. 44.50 respectively; when plants are utilized as per the design capacity. These costs are high and not affordable by the rural population. The RO plants were socially acceptable since the population was satisfied with the treated water quality.
Effects of a porous pavement with reservoir structure on runoff water: water quality and fate of heavy metals
Authors: Legret Michel , Colandini Valérie
Published: May 2018

The present paper reports a study conducted to compare pollutant loading of runoff waters either collected at the outlet of a porous pavement with reservoir structure or coming from a nearby catchment drained by a conventional separate sewarage system, on the experimental site of Rezé (France). The mean pollutant loads measured at the reservoir structure appear notably lower than those measured at the reference catchment. A sampling operation of materials carried out in the porous pavement have confirmed the accumulation of metals in the porous asphalt and the absence of soil contamination under the reservoir structure. An attempt at mass balance for heavy metal distribution into the reservoir structure was made. The amount of metal evacuated at the outlet of the reservoir structure is generally low. Lead is mainly retained by clogging particles and between 57 and 85% of Cu, Cd and Zn are evacuated in the infiltrated water.
Simulation of heavy metal pollution from stormwater infiltration through a porous pavement with reservoir structure
Authors: Legret M. , Nicollet M. , Miloda P. , Colandini V. , Raimbault G.
Published: May 2018

A laboratory experiment was set up to examine the ability of porous asphalt to retain metallic pollution. The results obtained confirm the retention of metals (Pb, Cu, Cd, Zn) by clogging particles, and a decrease in lead concentration can be observed in infiltrated runoff water. Moreover, the simulation of heavy metal transfer into the soil was carried out using the mathematical model LEACHM. The increase of Pb, Cu and Zn contents in soil appears slight after 50 years and well below regulation threshold values. The increase of Cd content is relatively more important. For infiltrated water, the results show a pollutant migration, especially for Cd, down to 30 cm. Nevertheless, the risk of groundwater pollution appears low.
Impact of the volume of rain water on the operating constraints for a treatment plant
Authors: Dormoy T. , Tisserand B. , Herremans L.
Published: May 2018

The new regulations require an increased amount of treatment of stormwater and a reduction of pollution loads discharged into the natural surroundings to be considered.

Drainage systems therefore and particularly wastewater treatment plants should be sized correctly to cope with these peaks. Using a simulation software of wastewater treatment plant with activated sludge, such as SIMBAD, enables us to check that planned structures are appropriate in relation to the effluent quality requirements laid down, and to fix the most appropriate operating procedures. Operating constraints on a plant for treating stormwater are not negligible. It is advisable to allow for increased sludge production, O2 requirements and also sludge quality (fermentability).
Development of new low cost defluoridation technology (krass)
Authors: Agarwal Kailash C. , Gupta Sunil K. , Gupta Akhilendra B.
Published: May 2018

Systemic fluorosis is an endemic problem in several developing countries. In India 15 states are endemic for fluorosis, of which 5 have indicated hyperendemicity for fluorosis in all districts. WHO standards permit only 1 mg/l as a safe limit for human consumption. People in several districts of Rajasthan are forced to consume water with fluoride concentrations of up to 44 mg/l which has resulted in permanent deformities, joint pains, general debility and misery. About 60% of fluoride intake is through water. Considerable work on fluoride removal from water has been done all over the world. However a safe, efficient, free from residual aluminium in treated water, and cost effective defluoridation technique/process is not available and needs to be developed in order to prevent the occurrence of fluorosis. This paper describes the development of a defluoridation process which differs from the known processes in its simplicity, cost effectiveness and results in traces of residual aluminium in treated water. The parameters like fluoride concentration, temperature, pH, alkalinity, humidity and total dissolved solids of input water do not affect this process.
In-situ performance of a passive treatment system for metal source control
Authors: Sansalone John J.
Published: May 2018

Urban stormwater often contains high levels of traffic-generated metal elements and particulates. These constituents are transported by stormwater runoff to surficial soils, drainage systems and receiving waters. This paper summarizes the in-situ field-scale performance of a passive treatment system called a partial exfiltration trench (PET) for source control of these constituents. For stormwater runoff infiltrated into the PET media, treatment occurs primarily by sorption and filtration. Previous bench-scale testing indicating a design life exceeding 10 years, demonstrated the potential viability of the PET, and justified construction and monitoring of a field-scale PET. In-situ performance of an instrumented field scale PET indicates mass removal efficiency generally exceeds 80% after 1 year of runoff loadings. Exfiltration from the PET to clayey glacial till soils has exceeded 30% for selected runoff events.
Wetland Projects Developed in Brazil
Authors: Salati E. , Salati Eneida , Salati E.
Published: May 2018

The first studies with constructed wetlands undertaken in Brazil were the result of observations made from the Amazon flood plains. The first attempt to use this capacity to change the quality of the water, in the sense of purification performed in Brazil using constructed wetland systems, was made by Salati et al. (1982) After that, new technologies were developed in a focused attempt to increase the efficiency of the system and reduce investments. Over these 18 years, persuading the Brazilian scientific community as well as the environmental control agencies to give due attention to this kind of research has required endless efforts. Only in recent years have major institutions responsible for sewage treatment and potable water supply been concerned with this type of technology for solving real problems. These institutions are as follows: SABESP (Basic Sanitation Company of São Paulo State), SANEPAR (Sanitation Company of Paraná State) and CESP (Electric Company of São Paulo State). One of the private institutions that has systematically worked in the design and projects of constructed wetlands is the Institute of Applied Ecology. This institution has enhanced and developed a water depuration system based on the purifying capacity of the soil. The wetlands with filtering soils are systems formed by overlapping layers of crushed stone, gravel and soil planted with rice. This technology has been used in sewage treatment and also in water supply systems.
Treatment of Wastewater Effluent from a Natural Gas Compressor Station
Authors: Johnson Keith D. , Martin Craig D. , Davis Travis G.
Published: May 2018

Florida Gas Transmission Company (FGTC), an Enron/Sonat affiliate, owns and operates a major interstate natural gas pipeline system that extends from South Texas to South Florida. At various locations along the pipeline are located compressor stations that boost the pressure of the natural gas flowing through the pipelines. As part of their normal operation, these stations generate small amounts of oily effluent as a result of cooling water blow-down, engine/parts wash-down, lube-oil-contaminated wastewater and rainwater from containment areas. In early 1997, economic considerations led FGTC to pursue alternative technologies to replace portions of the traditional treatment system. This paper reviews a trial effort undertaken by Wetland Sciences, Inc. to evaluate the technical feasibility of utilizing constructed wetlands to treat wastewater generated by the natural gas compressor station. The ultimate goal being the application of this technology to FGTC's other compressor stations.
Consequences of diffuse pollution on the water quality of rivers in the watershed of the lagoon of Venice (Italy)
Authors: Bendoricchio G. , Calligaro L. , Carrer G. M.
Published: May 2018

The results of three water quality monitoring programs implemented in the watershed of the Lagoon of Venice are presented. The programs focus on nutrient discharge because of its critical effect on eutrophication of the Lagoon. One of these programs is concerned with the long term variation of water quality. It shows the positive effect induced by the interventions on point source pollution of urbanised areas. It results in the reduction of ammonia concentration and in the increase of dissolved oxygen downstream of major cities. It also shows the negative effect of increases in corn crops in upland areas on the nitrate nitrogen concentration at the sources of major rivers. The short term monitoring program shows the quick variation of nutrient concentrations during rain events in the rivers, and the close relation between the diffuse pollution sources and the deterioration of water quality. The total nutrient loads measured at the monitored river outlets confirm the loads predicted by mathematical models for the whole basin, and the importance of the diffuse pollution loads on the global loads discharged into the Lagoon. The progress in reduction of point source pollution increases the role of the diffuse sources, and demands for urgent and strong intervention on those to reach the final goal of stable mesotrophic conditions in the water body. Finally, data analysis of the monitoring programs also indicates an effective strategy for further monitoring of the river basin focused on the effectiveness of the pollution abatement program, and the real time control of water quality for the management of the Lagoon of Venice.
The Tertiary Treatment Pilot Plant of Publiser SPA (Florence, Tuscany): A Multistage Experience
Authors: Masi F. , Martinuzzi N. , Loiselle S. , Peruzzi P. , Bacci M.
Published: May 2018

The multiservice company PubliSer SpA has constructed and monitored the operation of a multistage tertiary constructed wetlands wastewater treatment pilot plant for experimental and demonstration purposes. The facility was designed by and is partially monitored by the environmental engineering company IRIS SaS in Cerbaia, Florence, Italy. The experimentation with natural wastewater tertiary treatments is particularly important within central Italy as there are recurring environmental problems related to the poor functioning of small wastewater treatment systems. The present study is designed to compare the utility and efficiency of different multistage configurations following an active sludge process through an intensive monitoring programme that was initiated in November 1997. In this paper, we report the principal design specifications, a detailed description of the pilot plant, the dimensioning criteria and an analysis of the influent and effluent characteristics (COD, BOD, N, P, microorganisms, TSS, etc.) for each compartment monitored in the first period of plant operations. The pilot plant consists of two experimental lines, each characterised by a first and second treatment stage. The effluents of the first stages are divided into three different second-stage basins. The plant demonstrated high removal of nutrients, a good buffering capacity and a reasonable reduction of microorganisms after only a limited number of months of operation. Continued monitoring and comparison of the different constructed wetland strategies is providing interesting information for future designs and operation.