bluuebunny/crossref_metadata_2025_split huggingface dataset:
Retention and expression of recombinant plasmids in suspended and biofilm-bound bacteria degrading trichloroethene (TCE)
Authors: Bryers James D. , Sharp Robert R. 
Published: May 2018

Exposure of plasmid recombinant microorganisms to an open environment, either inadvertently or intentionally, requires research into those fundamental processes that govern plasmid retention, transfer and expression. In the open environment, a majority of the microbial activity occurs associated with an interface, within thin biological layers consisting of cells and their insoluble extracellular polymer, layers known as biofilms. Current toxic wastewater or wastegas treatment reactors exploit bacterial biofilm systems for certain system operating advantages.
Using recombinant bacteria within a biofilm reactor to degrade xenobiotic wastes requires finding a suitable host to harbor and express the desired plasmid phenotype. Suitable host characteristics include: the ability to produce copious amounts of biofilm, resistance to waste-related injury and toxicity, and the ability to retain and express the desired plasmid during long term operation. This paper reports on a laboratory evaluation of factors governing plasmid retention and the expression of trichloroethene (TCE) degradative capacity in both suspended and biofilm cultures.
Biodegradation of aniline
Authors: Gheewala Shabbir H. , Annachhatre Ajit P. 
Published: May 2018

Discharge of aniline to the environment must be controlled as aniline is toxic to aquatic life and also exerts additional oxygen demand due to nitrification reaction involved during its biodegradation. Organic carbonaceous removal by heterotrophs during aniline biodegradation releases NH4+ which is the substrate for autotrophic nitrifying bacteria. However, aniline is toxic to nitrifying bacteria and severely inhibits their activity. Accordingly, batch and continuous studies were conducted to assess the biodegradation of aniline and its inhibitory effect on nitrification. Synthetic wastewater was used as feed with aniline as sole carbon source for mixed microbial population.
Experiments were conducted at ambient temperatures of 30–32°C. An aerobic activated sludge Unit was operated at an HRT of about 13 hours and SRT of about 12 days. Biomass from aerobic activated sludge process treating domestic wastewater was acclimatized to synthetic wastewater Containing aniline. Removal efficiencies more than 95% were obtained for feed aniline concentrations upto 350 mg/l with insignificant inhibition of nitrification due to aniline. Ammonia oxidation rates of about 20–115 mgNH4N/l/d were observed.
Batch tests were carried out to test the inhibitory effects of high initial aniline concentrations on nitritication. Carbonaceous removal by heterotrophs proceeded rapidly within 4–6 hours with nitrification picking up as soon as aniline concentration dropped below 3–4 mg/l. For higher initial aniline concentration more than 250 mg/l, complete nitrification did not take place even after aniline Concentration dropped below 3–4 mg/l.
Assessment of the microbial toxicity test and its application for industrial wastewaters
Authors: Chen Chiu-Yang , Huang Jau-Bin , Chen Shing-Der 
Published: May 2018

In this study, two microbial bioassays, i.e. the commercialized Microtox® test and the specific oxygen uptake rate (SOUR) method, are used to assess the individual response of existing wastewater treatment facilities in several high-intensity pollution industries. Initially, the microbial toxicity of manufacturing effluents from a petrochemical industry are assessed. The toxicant sources in the manufacturing effluents are then investigated to develop the baseline of the waste reduction in the manufacturing processes. According to these results, the amount of aldehyde group contributes the majority of the microbial toxicity in the wastewater. Therefore, the abatement of the aldehyde wastewater may be the most effective factor to release the loads for following wastewater treatment facilities.
To control the discharge sources to the treatment facilities (WWTP), WWTPs with high-intensity pollution industries and public WWTPs in three industrial districts are further evaluated with their effluents to determine the primary contributor of toxicants. From the effluent toxicity results, the relationship between organic loads and toxic effluents exhibits a positive conjunction in the high-intensity pollution industries. If these industries can enhance their removal efficiency of organic compounds in the pretreatment system, the toxicity of their effluents can be effectively reduced. Consequently, the following treatment facilities can perform more efficiently to satisfy their needs.
Chemical characterization and biotreatability of effluents from an integrated alkaline-peroxide mechanical pulping/machine finish coated (APMP/MFC) paper mill
Authors: Schnell A. , Sabourin M. J. , Skog S. , Garvie M. 
Published: May 2018

As part of an extensive audit of the Alkaline-Peroxide Mechanical Pulping (APMPTM) plant at the Malette Quebec Inc. mill in St. Raymond, Que., effluents were sampled from various stages of the process for comprehensive chemical characterizations, aquatic toxicity testing and anaerobic biotreatability assessments. In addition, untreated and secondary treated combined effluent from the integrated paper mill were sampled to determine the effectiveness of a conventional activated sludge process at the mill site. During the one-day sampling period, the APMP plant processed a mixed wood furnish consisting of 50% spruce/balsam fir and 50% aspen, with a chemical charge of 3.5% sodium hydroxide and 3.8% hydrogen peroxide on oven-dry fibre, while the Machine Finish Coated (MFC) paper production rate was 100 odt/d (oven dry metric tonnes per day).
Measured production-specific contaminant discharge loadings from the novel APMP process were 56 kg BOD5/odt and 155 kg COD/odt in a combined effluent flow of 28 m3/odt. Sources of process effluent were chip washing, three stages of wood chip pretreatment and chemical impregnation (i.e., Impressafiner stages), interstate washing and pulp cleaning. The three Impressafiner pressates were found to be the most concentrated (i.e., 12-26 g COD/L) and toxic streams. Microtox testing of the pressates revealed EC50 concentrations of 0.07-0.34% v/v. The warm and concentrated effluents generated by the non-sulphur APMP process were found to be highly amenable to anaerobic degradation as determined by batch bioassay testing. Filterable BOD5 and COD(f) of the process effluents were reduced by 87-95% and 70-77%, respectively, with corresponding theoretical methane yields being attained. Acid-soluble dissolved lignin compounds exhibited biorecalcitrance, as revealed by limited removals of 34-55%, and were the main constituents contributing to residual COD(f), while resin and fatty acids (RFA) were reduced by 80-94%. The conservatively operated full scale activated sludge treatment process achieved a similar high 74% COD(f) removal from the whole mill effluent, while BOD5 and RFA reductions were virtually complete and the treated effluent was non-toxic, as measured by Microtox.
Solid, slightly soluble phosphorus compounds as nutrient source in activated sludge treatment of forest industry wastewaters
Authors: Rantala Pirjo-Riitta , Wirola Hannu 
Published: May 2018

The aim of the study was to determine if solid, slightly soluble compounds can be used as nutrient source in activated sludge treatment plants instead of liquid phosphoric acid. Four different solid materials were tested in lab-scale solubility tests to find compounds which are least soluble. Two materials were chosen for further studies: apatite and raw phosphate. The use of apatite and raw phosphate as nutrient source was studied in lab-scale activated sludge reactors along with a control reactor where phosphorus was added in liquid form. The phosphorus dosage, measured as elementary phosphorus, was the same for all three reactors. The reactors were fed with pre-clarified chemi-thermomechanical pulp mill (CTMP) wastewater.
There were no significant differences in the reductions of organic matter between the three reactors. The mean effluent concentration of total phosphorus was 3 mg P/l in the control reactor and less than 1 mg P/1 in the other two reactors. The soluble phosphorus concentration was more than 2 mg P/l in the control reactor and less than 0.5 mg P/l in the other two. Apatite was an even better nutrient source than raw phosphate. Further lab-scale tests were conducted using two different grain sizes of apatite. No significant differences were found between the studied grain sizes (&lt;0.074 mm and 0.074 mm-0.125 mm).
Apatite was then used in full-scale at a CTMP-mill two different times. The experiments showed that the mean concentrations of phosphorus can be reduced radically by using apatite as a nutrient source instead of liquid phosphorus. Solid phosphorus compounds are a viable alternative to reduce the phosphorus load from forest industry wastewater treatment plants.
Practical experiences with aerobic biofilters in TMP (thermomechanical pulping), sulfite and fine paper mills in Canada
Authors: Kantardjieff A. , Jones J. P. 
Published: May 2018

An industrial aerobic biofilter technology has been piloted extensively in Canada on several types of pulp and paper mill effluents, resulting in one full scale operational facility at one Canadian fine paper mill. In addition two industrial scale pilot plant tests were performed with the same technology, one in an integrated sulfite pulp and paper mill and one in a TMP mill. In the case of the fine paper mill, the full scale plant has two cells (8 m × 8 m × 6 m height of the media) and treats an unclarified but screened effluent with a loading of 3500 kg BOD/d. The system produces low quantities of biosludge (0.28 kg TSS/kg BOD removed), has a rapid rate of recovery after shock loadings and is very energy efficient (150 kW installed power for aeration).
Pilot plant treatability studies were performed at one integrated Canadian sulfite mill using a combination of a biofilter-aerated lagoon system. The biofilter treated the most concentrated stream (sulfite pulp mill effluent) and this stream was then combined with the remaining wastewaters of the mill and polished in an aerated stabilization basin (ASB). The high quality ASB effluent (50 mg BOD/L/30 mg TSS/L) was non toxic to rainbow trout, Daphnia magna and photoluminescent bacteria.
Integrated TMP mill effluents were treated in a 5 m3 aerobic biofilter filled with two types of media (10 to 20 mm and 20 to 30 mm). Under average loading conditions of 3.5 kg BOD/d.m3 media, the system produced effluents meeting regulation limits for BOD, TSS as well as for toxicity.
Combined biological nitrification and denitrification of high-salinity wastewater
Authors: Dahl C. , Sund C. , Kristensen G. H. , Vredenbregt L. 
Published: May 2018

The focusing on the discharge of nitrogen compounds to aquifers has put pressure on power plants to look into removal of nitrogen compounds from the gas scrubbing liquors (DESOx and DENOx). The scrubber liquor has a high salinity, a high chloride content and a temperature of about 40°. Initial laboratory tests to evaluate the possibility of performing biological nitrification and denitrification showed promise and a pilot-scale test unit was established at one of the Danish coal-fired combined heat and power plant (AVEDØRE 1).
The pilot plant was operated under varying conditions with regard to temperature and chloride concentration. Maximum nitrification and denitrification rates were measured. At 30°C and 20 g Cl−/l, maximum nitrification and denitrification rates of 2 and 3 mg N/g VSS·h respectively were measured. In the effluent, concentrations of inorganic nitrogen were below 8 mg N/l.
Twice during the test period, inhibition of the biomass activity was caused by high concentrations of heavy metals. The high content of heavy metals was due to malfunction of pH control in the heavy metal removal plant. The nitrification process was more sensitive to heavy metals than the denitrification process, and during the two toxic events the nitrification rate decreased to zero.
The influence of rapid changes in the chloride and nitrite contents on nitrification was also examined. The results from the performed tests can be applied on other wastewaters with similar characteristics as these scrubber liquors i.e. with salinity. As an example fertilizer and pharmaceutical industries can be mentioned.
Probablistic analysis of runoff simulations in a small urban catchment
Authors: Calomino F. , Veltri P. , Piro P. , Niemczynowicz J. 
Published: May 2018

In Urban Hydrology, a basic question is whether or not the common methods involving the use of design storms bring to the the some results obtained by those methods that make use of real storms. In general, one can say that different design storms give good results when used with the appropriate model, or, conversely, that good results can be achieved through careful model calibration.
On the basis of 51 rainfall-runoff recordings obtained from the experimental catchment of Luzzi (Cosenza, Italy), the frequency distribution of the observed peak discharges was initially computed. Then the runoff events were simulated using Wallrus, a well known simulation model, taking as input the observed precipitations. The frequency distribution of the simulated peak discharges was compared to that of the observed ones, with the aim of calibrating the model on a statistical basis. After that, the rainfall events were analysed, obtaining the frequency distributions of the observed intensities over several durations and developing IDF curves of given frequencies and, then, the Chicago design storms.
The plotting positions of the peak discharges simulated by this way show a good agreement with the distribution of both the observed peak discharges and the peak discharges simulated through the real storms.
Large-scale nitrogen removal demonstration at the blue plains wastewater treatment plant using post-denitrification with methanol
Authors: Bailey Walter , Tesfaye Akile , Dakita Jerry , McGrath Michael , Daigger Glenn , Benjamin Alex , Sadick Thomas 
Published: May 2018

The Chesapeake Bay Agreement of 1987 calls for an overall reduction in nutrient loading of forty percent of 1985 levels by the year 2000. Signatories to the agreement include the states located in the Bay's watershed and the District of Columbia. The District's 16.2 m3/sec (370 mgd) Blue Plains Regional Wastewater Treatment Plant is the single, largest point source of nitrogen load to the Bay, discharging approximately 18 metric tons per day. In an effort toward meeting the nitrogen reduction goal, a post-denitrification demonstration study was recently begun to access its potential for long-term implementation.
The denitrification demonstration project involves operating half of the nitrification facilities in a nitrification-denitrification mode using methanol as a carbon source for post-denitrification. The other half continues operation in a nitrification-only mode as a control. The post-denitrification process was selected for demonstration because it utilizes existing facilities and may offer substantial long-term cost savings. Objectives of the study are to demonstrate the process without a negative impact on effluent quality, to verify performance and capacity, to determine the stability and limitations of the project, and to compare the process to other nitrogen-removal technologies.
Thus far, the process has been successful in removing nitrogen despite problems with phosphorus limitation and with the settling characteristics of the denitrification sludge. It is believed that insufficient phosphorus availability has been responsible for problems associated with settling, sludge yield, methanol use, and denitrification rates. Recently, phosphorus input to the denitrification process has been increased by reducing metal salt addition in upstream processes and preliminary results have been promising. If performance criteria are achieved without sacrificing plant capacity, the process will be continued at full scale.
Phosphorus retention in sediments1
Authors: Boers P. C. M. , Van Raaphorst W. , Van der Molen D. T. 
Published: May 2018

Phosphate is usually the most important growth limiting nutrient in aquatic environments. The availability of P is the result of external load and retention in the sediments. This latter is the result of a number of transport, microbial and chemical processes. The role of P in the productivity in systems and in the eutrophication process has initiated a large number of studies to the behaviour of P in sediments. Case studies in Veluwemeer, IJsselmeer, Wadden Sea and German Bight show that sorption on and binding in ferric (oxi)hydroxides, occlusion in calcium carbonates and authigenic mineral formation are the most important retention processes.
However, all this research did not result in totally new approaches in lake restoration, nor did knowledge of internal P loading result in large scale applications of well-known sediment restoration techniques. It did result in more realistic expectations of lake restoration programmes.
At the same time, renewed interest in the overall role of phosphate in the functioning and productivity of systems is emerging. The most important new items are: the role of the productivity is examined at large scale levels; the coupling of productivity with several large scale material cycles and global environmental problems and the study of the behaviour and fate of phosphate within the context of the functioning of entire watersheds.
The advantages of a constructed reed bed based strategy for small sewage treatment works
Authors: Griffin P. , Pamplin C. 
Published: May 2018

The advantages of the use by a major UK water utility serving 8 million people in central England of constructed subsurface flow reed beds for secondary, tertiary and storm water treatment at small sewage treatment works is placed in context with improved permit compliance to more stringent standards and a continuing downward pressure on operating costs. Capital and energy costs are compared with the competing tertiary treatment process of recirculating sand filtration. Further economic advantage is gained by combining tertiary treatment and stormwater treatment.
With over 160 sites in operation by mid 1997 the success of the strategy has given confidence to allow for the early or emergency installation of reed beds to improve or maintain effluent quality before replacement, or in one case the provision, of secondary treatment. Use of constructed reed beds is now being extended to larger facilities where only a proportion of the flow needs to be treated to achieve standards. For tertiary treatment reed beds there is an additional environmental benefit with the typical removal of 10.7 mg/l of total nitrogen.
Trends in water quality and algal growth in shallow Frisian lakes, The Netherlands
Authors: Maasdam R. , Claassen T. H. L. 
Published: May 2018

About 20 shallow lakes form, together with interconnected canals, one hydrological water system in the province of Friesland. Total water surface area meets 14,000 ha, of which the lakes cover 10,000 ha. The regional catchment area is about 305,000 ha. In summer periods inflow of water from Lake IJsselmeer keeps the system on a constant water table of 0.52 m below sea level.
At the end of the sixties the lakes became hypertrophic. Algae were dominating the biocenoses and submerged water plants disappeared. Systematic investigations started in 1970, and biological data were included from 1976 on. During twenty years a stable, but highly eutrophic situation, passed. Blue-green algae, especially Oscillatoria agardhii, were dominating the phytoplankton. Submerged vegetation was absent and bream dominated the fish-stock.
From 1991 onwards there is a slight improvement in water quality. Transparency increased, phosphorus concentration and algal biomass decreased. Also a shift in phytoplankton species occurred. Dominance of O. agardhii decreased and species diversity increased. First submerged water plants recovered in 1994. Improvements are induced by a combination of measures and a culmination of small effects. Results of 14 years of water quality research are presented. Results are given as trends in time. Attention is paid to the spatial gradient in the province as well. From south to north the chain-arranged lakes represent a remarkable pattern of increasing trophic state, caused by regional loading of nutrients.
Assessment of leaching tests on construction material made of incinerator ash (sewage sludge): investigations in Japan and Germany
Authors: Wiebusch Bernd , Ozaki Masaaki , Watanabe Haruki , Seyfried Carl Franz 
Published: May 2018

Heavy metal release from bricks or blocks made of sewage sludge considerably decreases by sintering or cement consolidation. With such treatment, the enviromnental compatibility of recycled material can be ensured. In the framework of joint German-Japanese research, two types of leaching tests were introduced to develop a standardized test for construction material made of sewage sludge. One type is considered as a worst-case-test with low pH-values of 4-5 which describes the leaching availability under strong natural conditions (e.g. acid rain). The other type is a standardized test without pH-control. Both types of tests are investigated by using crushed samples of blocks.
Generally, there are two different ways for a sustainable assessment of the enviromnental compatibility. One way is to use a test with a low pH-value like the worst-case-tests. The other way is to crush the sample in small particles to produce large surfaces when using a standardized test. The smaller the particle size is, the higher is the concentration of heavy metals in the eluate. From the Japanese point of view, blocks are usually utilized in original shape, small particles are not appropriate as samples. That is why medium-sized particles are used for the leaching tests. But using “bigger” particles, lower pH-values can be used. Therefore, a modified Swiss method is assumed to be suitable as a new standardized test for the effect of acid rain. This method is discussed from the point of view of sample diameter. From the German point of view, crushed samples with diameter &lt;10 mm are used in combination with a standardized test. The heavy metal release from Japanese re-products is very low, and it has a close relationship with the release of the alkaline and alkaline earth metals. This effect can be shown on ash bricks from Germany also. Considering recommended limits in Germany, higher firing temperatures of &gt;1100°C should be used.
Optimised lamellae settling process for run off water treatment
Authors: Bridoux G. A. , Villeroux A. , Riotte M. , Huau M. C. 
Published: May 2018

Since the more stringent new french standard of the 3rd of January 1992 relating to water and embracing Urban Run Off Water Discharges during wet weather, some research works have been carried out to treat run off water. In particular, processes based on lamellae settler have been studied.
The study presented in this paper describes optimal conditions achieved on a lamellae settler prototype and the results obtained. Parameters investigated were as follow:– injection of coagulant (ferric chloride) controlled by the Suspended Solids (SS) flow feeding the lamellae settler– energy input in the flocculator to improve flocs polymerisation– sludge scraped in the thickened area– optimum adjustment of extracted sludge.
Sludge recirculation combined with on line monitoring of Suspended Solids in the flocculator allowed the maximum sludge loading to be established.
Those optimisations were applied with an hydraulic load of 150 m.h−1. Removal efficiency were 70% for Suspended Solids and 60% for Chemical Oxygen Demand (COD). The concentration of extracted sludge was 30 g.l−1.