bluuebunny/crossref_metadata_2025_split huggingface dataset:
Kinetics of accelerated solid-state fermentation of organic-rich municipal solid waste
Authors: Viéitez E.R. , Mosquera J. , Ghosh S. 
Published: May 2018

Biotransformation of landfill solid wastes is a slow process requiring decades for completion. Accelerated anaerobic fermentation in modulated landfill environments may alleviate or eliminate pollution of land, water and air. This research was undertaken to demonstrate the application of biphasic fermentation to a simulated laboratory-scale landfill to effect rapid biomethanation of biodegradable solids.
The biphasic process consisted of solid-state, acidogenic fermentation of the organic fraction of MSW followed by biomethanation of acidic hydrolysates in a separate methane fermenter. Solid-state fermentation of the MSW with effluent recirculation resulted in rapid hydrolysis, acidification and denitrification, with soluble COD and VFA concentrations accumulating to inhibitory levels of 60,000 mg/l and 13,000 mg/l, respectively, at a pH of 4.5. The landfill gas methane concentration reached a maximum of 55 mol.%. By comparison, the methanogenic reactor produced high methane-content (70–85 mol.%) gases. The biphasic process effected carbohydrate, lipid, and protein conversion efficiencies of 90%, 49%, and 37%, respectively. Development of a Monod-type product-formation model was undertaken to predict methane formation and to determine kinetic parameters for the methanogenic processes in the simulated landfill and separate methane reactors. A first-order solids hydrolysis rate constant of 0.017 day−1 was evaluated to show that landfill solids hydrolysis was slower than the inhibited methanogenesis rate.
Can stored sludge cake be deodorised by chemical or biological treatment?
Authors: Lambert S. D. , McGrath K. E. 
Published: May 2018

The storage of sludge cake provides an opportunity for septicity to develop, withattendant odours. Moreover, the odour prevention, containment and minimisation procedures used successfully in the rest of the works may not be adaptable to sludge storage and subsequent transport and disposal. Odourscan be released throughout storage and, in addition, the subsequent movement of the cake can release high concentrations of odours which have accumulated.
This paper focuses on the use of five types of chemical and biological treatment product to remediate odour in stored cake sludges: oxidising agents, bacteriological/enzymatic preparations, biological suppressants, nutrients, and odour neutralisers. Their action is described in terms of their effects on the microbial population of the sludge, the types of odours they are designed to eradicate, and how they are used in practice.
Enumeration of Cryptosporidium oocysts from surface water concentrates by laser-scanning cytometry
Authors: Zanelli F. , Compagnon B. , Joret J. C. , de Roubin M. R. 
Published: May 2018

The utilization of the ChemScan® RDI was tested for different types of water concentrates. Concentrates were prepared by cartridge filtration or flocculation, and analysed either without purification, or after Immunomagnetic separation (IMS) or flotation on percoll-sucrose gradients. Theenumeration of the oocysts was subsequently performed using the ChemScan® RDI Cryptosporidium application. Enumeration by direct microscopic observation of the entire surface of the membrane was carried out as a control, and recoveries were calculated as a ratio between the ChemScan® RDI result and the result obtained with direct microscopic enumeration.
The Chemscan enumeration technique proved reliable, with recoveries yielding close to 100% in most cases (average 125%, range from 86 to 467%) for all the concentration/purification techniques tested. The quality of the antibodies was shown to be critical, with antibodies from some suppliers yielding recoveries a low as 10% in some cases. This difficulty could, however, be overcome by the utilization of the antibody provided by Chemunex.
These data conclusively prove that laser scanning cytometry, which greatly facilitates the microscopic enumeration of Cryptosporidium oocysts from water samples and decreases the time of observation by four to six times, can be successfully applied to water concentrates prepared from a variety of concentration/purification techniques.
Options for beneficial reuse of biosolids in Victoria
Authors: van Oorschot R. , de Waal D. , Semple L. 
Published: May 2018

This paper presents a synopsis of current biosolids management in Victoria as well as an overview of some biosolids processing technologies. Indicative capital and annual costs to upgrade wastewater sludge management facilities at Victorian wastewater treatment plants to maximise safe beneficial reuse of biosolids and sludge products are provided.
The data will be particularly useful for preliminary assessment and planning purposes of biosolids management strategies for government, non-metropolitan urban water authorities and regional waste management groups.
Indicative cost curves are presented for various sludge treatment and biosolids reuse options applicable to treatment plant sizes between 2000 and 200,000 ep.
Evolution of the Southpest Wastewater Treatment Plant
Authors: Jobbágy A. , Literáthy B. , Farkas F. , Garai Gy. , Kovács Gy. 
Published: May 2018

The treated effluent of the Southpest Wastewater Treatment Plant is discharged into a small, low-flow branch of the Danube susceptible to eutrophication. The first, high-load activated sludge system with a hydraulic retention time of 2.5 hrs in the aerated basins, was installed here in 1966. The paper presents the evolution of the technology by illustrating the effects of the different changes carried out since 1991.
Reconfiguration of the existing activated sludge basins connected originally in parallel into an arrangement of tanks in series increased the settleability of the sludge as well as the efficiency of COD removal significantly. Introduction of an anaerobic zone preceding the aerated basins facilitated biological excess phosphorus removal with a consequent release in the thickener and digester. Introducing lime addition into the recycled sludge processing wastes significantly improved the performance of the system. However, since there had been no provision built for eliminating the nitrate content of the recycled sludge, efficiency of phosphorus removal proved to be dependent on the eventually occurring nitrification.
In order to achieve both an effective nitrogen and phosphorus removal the current technology established in 1999 applies a nitrification and a denitrification filter following the activated sludge unit and uses precipitation for phosphorus removal.
WWTPs in rock – an economical and environmental alternative
Authors: Andersson C. , Hultgren J. 
Published: May 2018

To meet increased load or requirements on effluent standards the upgrading of a WWTP may be carried out with a large biological stage meaning higher investment costs but lower operation and maintenance (O&M) costs, or with a compact biological stage meaning lower investment costs but higher O&M costs.
Henriksdal and Käppala WWTPs in Sweden, both built in rock with large biological reactors operated with pre-denitrification, show lower specific O&M costs than Himmerfjärden WWTP, operated with post-denitrification in a fluidised bed. It is the other way round for the specific capital costs. The total specific cost, which is the sum of the specific O&M and capital cost, is a useful tool when choosing an alternative for upgrading. The experiences from these three plants show that a “large volume alternative” is competitive with a “compact alternative” if the volumes can be available at a reasonable cost. With proper technology rock chamber plants may be comparatively cheap to build. The economical and environmental advantages are discussed in this paper.
Modeling and simulation with microsites on vertical concentration profiles in sediments of aquatic zones
Authors: Sakita S. , Kusuda T. 
Published: May 2018

Modeling of reactions in sediments with microsites which have particulate organic matter (POM) in their cores as energy source for bacteria (called the M-S model) and subsequent simulation using it are executed for the explanation of vertical concentration profiles in sediment, and for the comparison with a conventional vertically one-dimensional transport-reaction model (the V-1 model). The POMs in the sediment are assumed to be sphereical with a range from 50μm to 500μm in radius and a logarithmic normal distribution.
The POM size and distribution alter the concentration profiles in the sediment in the M-S model, especially NO3--N profiles, because of dependence of denitrification rate on the POM characteristics. Anoxic and anaerobic reaction rates in the sediment in the V-1 model are underestimated because of no microsite. For the practical purpose of calculating concentration profiles of substances, the M-S model has higher accuracy and controlability, and is useful for detailed explanation of reactions in the sediment.
Operational results and experience with submerged fixed-film reactors in the pretreatment of industrial effluents
Authors: Schlegel S. , Teichgräber B. 
Published: May 2018

Submerged fixed-film reactors are ideal for the pretreatment of industrial effluents. The advantages lie not only in the investment costs, but also in the operating costs. The pretreatment plants can be subject to higher loads than are possible with the activated sludge process. Consequently, considerably less space is required. And, last but not least, it is also possible to treat normally non-degradable industrial effluents. The prerequisites are that system-related general structural requirements are fulfilled and suitable materials are used for the fixed-film reactor.
They also offer considerable advantages in terms of operation compared to the activated sludge process, since both a higher oxygen transfer rate and yield are achieved, less sludge is produced and fewer personnel are required. All in all, the upstream submerged fixed-film reactor has proven to be an extremely reliable process, requiring little maintenance, that can cope, to a far-reaching degree, with load fluctuations of all types and reduce these. As a result, the operation of downstream treatment stages is also stabilized.
Fate of pesticides in a shallow reservoir
Authors: Itagaki N. , Nagafuchi O. , Takimoto K. , Okada M. 
Published: May 2018

Based on the horizontal and vertical distributions of pesticides in the river and the reservoir, the fates of pesticides in these systems were investigated in this study. Four pesticides, i.e., MEP, thiobencarb, BPMC and isoprothiolane had the highest concentrations among the eighteen pesticides. These pesticides in suspended components except isoprothiolane were detected not only during stormy weather days but also during dry weather days. The percent detection of pesticides in suspended component was 59.8-61.9% in MEP, 34.6-38.9% in thiobencarb and 17.0–19.0% in BPMC. However, isoprothiolane in the suspended component was undetectable.
These pesticides in the suspended component have existed as a part of the suspended solids in the river, then disappeared by sedimentation during the flow of the river from the upper stream to the backwater in the reservoir. On the other hand, the pesticides in the dissolved components that flowed into the reservoir were uptaken or adsorbed by phytoplankton. Moreover, the concentrations of the less absorptive pesticides like isoprothiolane have decreased by dilution and diffusion in the reservoir.
Novel aspects for management of xenobiotic compounds in wastewater treatment plants – linking theory, field studies, regulation, engineering, and experience
Authors: Jacobsen B. N. , Guildal T. 
Published: May 2018

Management aspects for control of environmental contaminants has widened from being focussed on heavy metals to a broader approach including specific organic compounds, inhibition of sensitive bacteria or algae, and newly identified environmental issues, e.g., endocrine disruption and antibiotic resistance.
Studies conducted at the Avedøre WWTP confirm the relevance of such newly discovered environmental problems, however, the order of magnitude of the effects do not seem alarming.
It is recommended in future research to establish links between occurrence of specific organic compounds and heavy metals to various measures of toxicity and bioaccumulation. Also data for specific biodegradation rates in WWTPs represent a bottleneck for simulating fate of specific organic compounds in the plants.
The performance of the waste stabilisation pond system at Boujaad, Morocco
Authors: Yagoubi M. , Echihabi L. , Foutlane A. , Bourchich L. , Jellal J. , Wittland C. , El Yachioui M. 
Published: May 2018

The wastewater stabilisation ponds system of the city of Boujaâd was constructed and put into operation in 1992. The two main objectives of this plant are the prevention of pollution of water resources and the environment by means of wastewater discharges as well as the saving of fresh water by means of reuse of treated wastewater for irrigation purposes. Within the period of March 1997 to March 1998 a comprehensive analysis campaign of both the raw and the treated wastewater at a number of different sampling points has been carried out in order to evaluate the treatment efficiency of this wastewater treatment plant.The results of these investigations showed an average raw wastewater flow of 1600 m3/d, which is well below the design flow of 2500 m3/d.
With respect to the physico-chemical treated wastewater quality and in comparison with the French treated wastewater standards (1980) these results indicated that 90 % of the wastewater samples showed BOD5-figures below the quoted French standard, whereas 83 % of the samples showed COD-figures above the corresponding French treated wastewater standard.
With average treated wastewater suspended solids contents of 56 mg/l the suspended solids removal rate has been determined as being in the range of 65 %.
If compared to the anticipated Moroccan wastewater standards for direct wastewater discharge into receiving water bodies as stipulated in the Moroccan Standards Project the obtained wastewater analysis results showed COD- and BOD5 values below these foreseen Moroccan wastewater discharge standards. The analysis results of SS, TKN and total phosphorus (Ptot) showed figures slightly above these Moroccan standards. In view of the microbiological wastewater characteristics the treated effluents of the Boujaâd WSP respond to the WHO directive with respect to wastewater to be used for restricted irrigation (category B).
Taking into consideration the CEC directive for wastewater generated by wastewater treatment plants and discharged to the environment, the efficiency of the Boujaâd WSP is relatively low with respect to the SS-removal, the removal of organic matter (expressed by BOD5 and COD) as well as the removal of nutrients (expressed by TKN and Ptot). This relatively low efficiency might basically be caused by the already highly diluted incoming raw wastewater, which again is caused by the effect of significant infiltration of groundwater into the sewerage network. Besides the evaluation of the overall treatment efficiency, detailed investigations of the performance of individual ponds have been carried out as well.
Volume reduction of produced water generated from natural gas production process using membrane technology
Authors: Visvanathan C. , Svenstrup P. , Ariyamethee P. 
Published: May 2018

This paper presents a case study of a natural gas production site covering various technical issues related to selection of an appropriate Reverse Osmosis (RO) system. The long-term field experience indicates the necessity of the selection of appropriate pretreatment systems for fouling-free RO operational conditions. The produced water has a variety of impurities such as oil and grease, process chemicals used for corrosion and scaling control, and dehydration of natural gas, etc. This situation leads to a complicated and extremely difficult task for a membrane specialist to design RO systems, especially the pre-treatment section.
Here as part of the pretreatment selection, two types of UF membrane modules viz. spiral wound and hollow fibre, with MWCO of 8000 and 50,000 Dalton respectively, were tested in parallel with NF membranes of the spiral wound type with MWCO 200 Dalton. The UF permeate is used as feed for RO compatibility testing. Both configurations of UF failed to be compatible, due to irreversible fouling of the RO membrane. The NF membrane, however, showed interesting results, due to membrane stability in terms of cleaning and fouling. The NF plant with 50% capacity gave a recovery of 75% and the RO plant gave a recovery of 60% versus the expected 92–95%. The long-term tests have indicated that the reminder of the membranes could be installed to achieve full capacity of the plant. This study also demonstrates the importance of selection of proper pre-treatment set-up for the RO system design.
Optimal membrane selection for Brackish water desalination
Authors: Oron G. , Bick A. 
Published: May 2018

An integrative approach for optimal membrane selection concerning desalting of brackish water is proposed. This approach is based on management modeling for the following subsystems: Intake, pretreatment, Reverse-Osmosis (RO) unit, post-treatment and brine disposal. The management modeling takes into account membrane performance considerations that include treatment levels and technical capabilities. Attention is also given to membrane replacement and permeates salinity.
The model is based on defining an objective (cost) function to be optimized. The optimum of the objective function is evaluated, subject to a series of technological and economical constraints. The results provide guidelines for optimal membrane selection, pretreatment technology and information regarding the system layout, optimal investment and water cost. According to the results, a design based on gravity filters and high flux membranes is preferred with respect to minimum permeate cost. Analyzing the results, indicates the sensitivity of the solution to interest rate and electric power cost.
Surface runoff pollution by cattle slurry and inorganic fertilizer spreading: chemical oxygen demand, ortho-phosphates, and electrical conductivity levels for different buffer strip lengths
Authors: Núñez-Delgado A. , López-Periago E. , Quiroga-Lago F. , Díaz-Fierros Viqueira F. 
Published: May 2018

As a way of dealing with the removal of pollutants from farming practices generated wastewater in the EU, we investigate the effect of spreading cattle slurry and inorganic fertiliser on 8×5 m2 and 8×3 m2 areas, referred to surface runoff chemical oxygen demand (COD), ortho-phosphates (o-P) and electrical conductivity (EC) levels, and the efficiency of grass buffer strips of various lengths in removing pollutants from runoff.
The experimental plot was a 15% sloped Lolium perenne pasture. Surface runoff was generated by means of a rainfall simulator working at 47 mm h-1 rainfall intensity. Runoff was sampled by using Gerlach-type troughs situated 2, 4, 6 and 8 m downslope from the amended areas.
During the first rainfall simulation, COD, o-P and EC levels were consistently higher in the slurry zone, more evidently in the larger amended area. During the second and third rainfall simulations, concentration and mass levels show a downslope drift into the buffer zones, with no clear buffer strip length attenuation.
Correlation between runoff and mass drift is clearly higher in the slurry zone.
Percentage attenuation in COD and o-P levels, referred to initial slurry concentrations - including rainfall dilution - were higher than 98%, and higher than 90% for EC.
Real-time control strategies for predenitrification - nitrification activated sludge plants biodegradation control
Authors: Suescun J. , Ostolaza X. , Garcia-Sanz M. , Ayesa E. 
Published: May 2018

This paper presents the real-time control strategies developed to regulate both the ammonia and nitrate concentration in the effluent of the new Vitoria WWTP (Spain). Nitrate control aims at the optimal use of the denitrification potential at any moment. For this purpose, the proposed control algorithm continuously adapts the internal recycle flow in order to maintain a desired nitrate set-point in the anoxic zone. Ammonia control aims at maintaining the required average concentration of ammonia in the effluent by manipulating the Dissolved Oxygen (DO) set-point.
The control strategies have been based on a hierarchical structure where a high-level or supervisory control selects the set-point of the low-level or conventional controllers. The design of the controllers was carried out using the Quantitative Feedback Theory QFT for the design of robust control systems. Moving average values of some variables have been introduced in order to eliminate the perturbations associated with the daily 24-hour profiles. The controllers have been verified using long-time dynamic simulations based on a mathematical model previously calibrated in pilot plant. Influent load and temperature used in the simulations correspond to the real values measured in the full-scale WWTP during 12 months. The results obtained in the simulations show the good performance and stability of the control strategies independently from external disturbances. A short-time experimental verification of the controllers in pilot plant with real wastewater is also presented.
Degradation of p-hydroxyphenylacetic acid by photoassisted Fenton reaction
Authors: Acero J.L. , Benítez F.J. , Real F.J. , Leal A.I. 
Published: May 2018

The chemical decomposition of p-hydroxyphenylacetic acid, a phenolic pollutant present in agro-industrial plant effluents, has been investigated by means of the Fenton's reaction and the photoassisted Fenton's reaction, the so-called photo-Fenton system. The degradation levels achieved have been compared to those obtained by applying other Advanced Oxidation Processes, such as the combination UV/H2O2. The optimum pH to carry out the decomposition of this organic compound by either Fenton or photo-Fenton systems was found to be pH = 3. The presence of buffers such as phosphate impedes these processes due to the formation of ferric complexes.
A reaction mechanism, which allows calculating the contribution of the radical reaction to the global process, has been proposed. According to this mechanism, the dominant way of degradation of p-hydroxyphenylacetic acid is through its reaction with the OH radicals originated in the photolysis of H2O2 and, especially, in the Fenton's reaction.