bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analysis of Water Quality Criteria in Mexico
Authors: Jiménez B. , Ramos J. , Quezada L. 
Published: May 2018

During the last decade, it has been acknowledged that, at national level, the availability of water is a trade-off between its temporary and spatial distribution as well as contamination problems. This situation has urged the Mexican Government to revise the plans and programs for the integrated management of hydric resources by analysing the institutional system, the legal frame and its effectiveness. Within this context, an essential aspect is to ensure the ordering of the uses and exploitation of water resources.
This paper shows that a revision of the effectiveness and applicability of the current water standards and laws is essential to satisfy the demands, and to have control over the different uses of water (drinking water for human consumption, the use of water for agricultural, municipal, industrial related activities and other purposes). Therefore, in this work, a redefinition of the Ecological Criteria of Water Quality has been proposed. The proposal establishes the Quality Criteria under a new perspective, wherein the set of parameters and their values constitute the goal of quality, in the sense that any type of water with such characteristics or better ones, cannot only be used as it is, but constitutes the most suitable water for such use.
Anoxic Phosphate Uptake in the DEPHANOX Process
Authors: Bortone G. , Libelli S. Marsili , Tilche A. , Wanner J. 
Published: May 2018

The innovative nutrient removal process scheme DEPHANOX proved to be very efficient because it maximises the utilisation of organic substrate for phosphorus and nitrogen removal. The process solves the competition for organic substrates among Poly-P organisms and denitrifiers as well as the problem of overgrowing of slow nitrifiers by faster organotrophs, typical of activated sludge. In experiments, DEPHANOX showed better P removal efficiency than a JHB configuration, working with a very low influent COD/TKN ratio. This paper reports the results of a simulation study that has been carried out to better understand the behaviour of the two configurations with a wide variety of influent wastewater characteristics and under dynamic conditions.
The results of the simulation confirmed the high P removal capacity of the DEPHANOX configuration with low influent COD/TKN ratios.
Tie and tre: an abbreviated guide to dealing with toxicity
Authors: Coombe Vyvyan T. , Moore Keith W. , Hutchings Matthew J. 
Published: May 2018

The UK environmental regulator, the Environment Agency, is at present in the process of introducing a revision to the effluent discharge consenting system, based on the assessment of whole effluent toxicity - so called Direct Toxicity Assessment (DTA). The concepts of the most ‘sensitive’ species and of risk assessment based on estimation of Predicted Environmental Concentration (PEC) form the basis of the proposed consenting structure. The objective is to control the toxicity of point source discharges to riverine, estuarine and coastal waters and it raises the need for understanding of the nature and expression of toxicity in such discharges.
Internationally recognised toxicity test protocols are well established, enabling the quantitative measurement of toxicity with levels of confidence similar to the more traditional physical and chemical determinands, such as individual organic solvents, COD or metals. However, traditional protocols are seen as resource intensive and as involving high cost. This paper presents some experiences from the Zeneca Brixham Environmental Laboratory in the characterisation of the toxicity expressed to freshwater and marine species by several chemical manufacturing effluents and in the conduct of a number of Toxicity Identification Evaluations (TIE) using both standard and enhanced protocols for toxicity testing.
Improvement of Sludge Settleability in Activated Sludge Plants Treating Effluent from Pulp and Paper Industries
Authors: Andreasen Kjær , Agertved Jeanette , Petersen Jens-Ove , Skaarup Henrik 
Published: May 2018

The main objective of many activated sludge plants treating wastewater from the pulp and paper industry is to remove COD only. These plants are often designed as high-load aerobic systems without any microbial selector system. As a consequence the sludge settling properties are normally poor due to fast growing filamentous microorganisms, which severely reduce the treatment capacity and the effluent quality.
Implementation of selectors, in which the substrate concentration and the metabolic pathways can be manipulated, has in many cases reduced the bulking sludge problems in activated sludge systems. An example of a successful upgrading of a Danish pulp industry wastewater treatment plant with an anoxic selector is presented. the use of a novel technique to investigate the in situ physiology of filamentous microorganisms is discussed. It is concluded that a successful application of selectors relies on detailed knowledge about: a) physiology and substrate requirement of the filamentous microorganisms, b) wastewater composition and c) substrate removal kinetics in the selector system.
Enhancement of Capacity and Efficiency of a Biological Waste Water Treatment Plant
Authors: Kaindl Nikolaus , Tillman Ulf , Möbius Christian H. 
Published: May 2018

The capacity and efficiency of the existing activated sludge waste water treatment plant at SCA Graphic Laakirchen AG needs to be enhanced due to an expected future increase in waste water flow and COD-load. For the case of an existing upper limit of COD discharges into the river, the COD reduction rate of the waste water treatment has to be increased to a degree which is unobtainable by biodegradation only.
Laboratory and pilot plant trials using a moving bed biofilm technique and an activated sludge treatment combined with ozone treatment and subsequent biofiltration have been performed with the aim to increase the COD reduction capacity and efficiency of the plant.
The results show that the COD reduction capacity of the existing activated sludge plant can be increased by more than 100% by integrating a moving bed biofilm pre-treatment stage into the plant. In addition, improved sludge separation in the secondary clarifier was established. A special benefit of the ozonation plus biofilter treatment is a controllable COD reduction between 20 - 90% related to the outflow of the activated sludge plant.
It is concluded that by integrating the investigated treatment techniques in the existing activated sludge plant the future increases in waste water flow and COD-Load can be handled satisfactorily without increasing bioreactor volume.
Performance of a combined biofilm-suspended growth system for wastewater treatment
Authors: Hamoda Mohamed F. , Al-Sharekh Hamed A. 
Published: May 2018

This paper summarizes the results obtained using the hybrid aerated submerged fixed-film (HASFF) reactor which utilizes suspended as well as attached biomass for the treatment of wastewater. The HASFF reactor consists of four compartments with an array of fixed ceramic plates maintained under diffused aeration to support attached biomass with suspended biomass recycle to promote suspended growth in the reactor. Wastewater from a municipal treatment plant was fed to the reactor and its activated sludge was used for recycling in the hybrid system. Four pilot units were operated in the plant at various HRTs (2, 4, 6 and 8 hrs) with flow rates in the range of 0.32 to 1.2 m3/d, using primary-settled wastewater under organic loading rates up to 0.7 g BOD/g BVS.d.
The data obtained showed that the overall BOD removal efficiencies were consistently above 94.0% at all HRTs, while the COD removal efficiencies ranged between 65.7–76%. The effluents' mean filtered BOD concentrations were between 4.5–7.5 mg/l whereas the mean filtered COD concentrations ranged between 70.0–89.6 mg/l. Increasing the hydraulic loading rate four-fold from 0.08 to 0.32 m3/m2.d had minor effect on the reactor's BOD and COD removal efficiencies indicating a robust biological process that is resilient to flow variation, thereby offering a viable treatment option for small plants. The HASFF process achieved organic removal and nitrification in a single reactor, with minimal sludge production. The organic removal rate was equally high at all HRTs whereas nitrification was directly proportional to the HRT, being higher at longer HRTs. The suspended biomass activity exceeded that of the attached biomass at shorter HRTs while the opposite was true at longer HRTs.
Environmental engineering education in conjunction with or as Part of social sciences curricula
Authors: Hahn H.H. 
Published: May 2018

Traditionally in Germany environmental engineering education took place within the context of a civil engineering programme. There were reasons for this: the beginning of much of what we understand today to be environmental works fell within the parameters of city engineering. There were and are advantages mostly in view of the necessary planning, construction and operation of environmental infrastructure. There are also disadvantages which become more and more pronounced as the field of environmental protection expands: the civil engineer frequently lacks basic training in disciplines such as biology and chemistry and carries a large and sometimes burdensome knowledge of other less relevant subjects. Thus, educators begin to look for alternatives.
This paper deals with an alternative that was developed some ten years ago and therefore has proven viable and successful: at the University of Karlsruhe students may choose to major in environmental engineering within the context or on the basis of an economics and business administration curriculum. The basic question here is as to what extent the student masters the field of environmental engineering if he or she has predominantly a solid background in social sciences and very little in natural sciences.
The paper will describe the curriculum in structure and intensity and evaluate the accumulated knowledge and suitability of these students in terms of actual environmental problems. This will be done in terms of examination performance parallel and/or relative to traditionally trained civil environmental engineers as well as in terms of topics successfully treated in Masters' theses. In conclusion, it is argued that such combination of curricula should not be confined to economic sciences and environmental engineering but also be planned for legal sciences and environmental engineering.
Two-phase anaerobic digestion of source sorted OFMSW (organic fraction of municipal solid waste): performance and kinetic study
Authors: Pavan P. , Battistoni P. , Cecchi F. , Mata-Alvarez J. 
Published: May 2018

The results of a two-phase system operated in different conditions, treating the source-sorted organic fraction of municipal solid waste (SS-OFMSW), coming mainly from fruit and vegetable markets, are presented. Hydraulic retention time (HRT) in the hydrolytic reactor and in the methanogenic reactor and also the temperature in the hydrolytic reactor (mesophilic and thermophilic conditions) are varied in order to evaluate the effect of these factors. The methanogenic reactor is always operated within the thermophilic range. Optimum operating conditions are found to be around 12 days (total system) using the mesophilic range of temperature in the first reactor. Specific gas production (SGP) in these conditions is around 0.6 m3/kgTVS.
A kinetic study is also carried out, using the first and the step diffusional models. The latter gives much better results, with fitted constants comparable to other studies. Finally, a comparison with a one-phase system is carried out, showing that a two-phase system is much more appropriate for the digestion of this kind of highly biodegradable substrate in thermophilic conditions.
Partitioning of Cr, Cu, Pb and Zn in sewage sludge incineration by rotary kiln and fluidized bed furnaces
Authors: Mininni G. , Braguglia C. M. , Marani D. 
Published: May 2018

The behaviour of four metals (Cr, Cu, Pb, Zn) during sewage sludge incineration was studied in eight pilot plant tests performed with a rotary kiln (RK) and a fluidised bed (FB) furnace. To simulate sludge co-incineration with hazardous wastes, in three FB tests feed sludge was mixed with chlorinated organic compounds. Chromium and copper showed similar concentrations both in bottom or cyclone ash and in fly ash, even at high chlorine input and high combustion temperature. In contrast, zinc and lead concentrations in fly ash produced in RK tests are one or two orders of magnitude higher than those in bottom ash. However, not even these two metals showed significant enrichment in FB tests carried out at high chlorine input. The predictive capability of a thermodynamic model was checked by comparing predicted metal volatilisation in the combustion chamber with experimental metal enrichment in the fly ash. Large discrepancies were observed in FB tests carried out at high chlorine content, where Pb, Zn, and Cu are predicted to volatilise in great extent, andin RK tests where zinc volatilisation is not predicted. Likely explanations of these discrepancies are the very short solid residence times in the FB furnace (non equilibrium conditions) and the incomplete mixing conditions in the RK furnace (pyrolysis pockets).
From the environmental impact point of view, the pilot tests suggest that sludge incineration with fluidised bed furnace is safer than the one using rotary kiln furnace.
Käppala 2001 – upgrading and expansion of the Käppala Wastewater Treatment Plant: project management
Authors: Bengtsson B. , Palmgren T. 
Published: May 2018

Käppala Association has the responsibility to receive and treat wastewater from 11 municipalities situated just north of Stockholm in Sweden. Running a tunnel system, 60 km long, and a treatment plant meet this responsibility. The Association was formed in 1957 and the tunnel system and the Käppala plant were taken into operation in 1969. The plant is situated in Lidingö, northeast of Stockholm. The load will in 1999 correspond to nearly 500,000 p.e.
The plant built in the sixties was running until the 31 March 1998 when a new part was taken into operation. During 1998–1999 the old part will be upgraded and the expanded and upgraded Käppala plant will run under ordinary conditions in the year 2001. The expansion was decided on the basis of improvement on four points namely:
1. Capacity improvement. The design year is 2020 and the estimated load will then correspond to about 700,000 p.e. The design load of the old part is 500,000 p.e.
2. Nitrogen removal. The Swedish Parliament specified in 1990 that at least 50% nitrogen removal should be achieved in the major treatment plants in Sweden.
3. Working conditions. Since the plant is housed in the Käppala rock special demands must be put on the working environment. The demands have increased during the years and the environment had to be improved substantially.
4. Odour. Complaints about odour among neighbors have long been a hot issue in Lidingö and the need for improvement was highly desirable. Also along the tunnel-system there were complaints about odour.
The decision to expand the plant was taken by the owners, nine municipalities in 1993 and the necessary permit from the National Licensing Board for Environment Protection was received in December 1993. The basis for the application to the Licensing Board was a principal design proposal. In this proposal, which was approved by the authorities, the overall treatment process design was determined.
Catalytic effects of high Mn(IV) concentrations on Mn(II) oxidation
Authors: Aydin S. , Tufekci N. , Arayici S. , Ozturk I. 
Published: May 2018

Manganese is one of the common constituents of impounded water and of many well waters. In public supplies, it causes difficulties such as staining of clothes, “black” residues on plumbing fixtures and incrustation of mains. In industrial supplies, it causes severe economic losses through discoloration of products, specks in finished paper, textile, food and beverage products, and reduction of pipeline carrying capacities. Manganese is not known to cause any health problems, and the above conditions are limited to existence of manganese content by 0.05 mg/l in drinking waters, and by 0.1 mg/l or less in industrial waters.
The aim of this study, is the removal of manganese (II) by oxidation with atmospheric oxygen, and to precipitate as MnO2 (s), from the waters with high manganese content. The oxidation of manganese (II) is studied in batch reactors in which the concentrations of manganese (IV) was in the range 0–700 mg/l . A quadratic equation has been given to determine the catalytic reaction rate constant as a function of manganese (IV).
Experimental comparison between MBBR and activated sludge system for the treatment of municipal wastewater
Authors: Andreottola G. , Foladori P. , Ragazzi M. , Tatàno F. 
Published: May 2018

The aim of the described experimentation was the comparison of a low cost MBBR and an activated sludge system (AS). The MBBR applied system consists of the FLOCOR-RMP® plastic media with a specific surface area of about 160 m2/m3 (internal surface only). The comparison with activated sludge (AS) was performed by two parallel treatment lines. Organic substance removal and nitrification were investigated over a 1-year period. Comparing the results obtained with the two lines, it can be observed AS totCOD removal efficiencies were higher than MBBR ones; the average efficiencies for totCOD removal were 76% for MBBR and 84% for AS. On the contrary, the solCOD removals resulted alike (71% for both systems).
In spite of the remarkable variations of wastewater temperature, mainly in winter (range of 5–21°C), the average ammonium removal efficiency resulted 92% for MBBR and 98% for AS. With an ammonium loads up to 1.0 g m2 d−1 (up to 0.12 kg m−3 d−1), nitrification efficiencies in MBBR were more than 98%. At higher loads decrease in the MBBR efficiency was registered; that is related to the increase in the applied COD load.
Performance of a system combining aerated lagoons and waste stabilization ponds in a temperate climate
Authors: Nameche T. , Dufayt O. , El Ouarghi H. , Vasel J.L. 
Published: May 2018

AbstractThe Bertrix wastewater treatment plant was designed and built for experimental purposes, especially for comparing aerated lagoons and stabilization ponds in a temperate climate. This plant was designed for a capacity of 7500 inhab. eq, and aerated lagoons were dimensioned to eliminate 50% of the organic load. The remaining load has to be degraded in the series of stabilization ponds.
In this paper we shall present the plant in more detail and the results of a 3-year study, i.e., 79 rounds of samples for each of the five ponds under study, placing emphasis on the performances of aerated lagoons and stabilization ponds. Principal components analysis (of inflow and outflow) of aerated lagoons and stabilization ponds will be presented and commented on. The most important factors are the hydraulic loading and the concentrations. Seasonal variations appear only in the basins' temperatures. The fates of nitrogen compounds are quite different from those of organic compounds, confirming that a high efficiency of nitrogen removal is difficult to achieve, especially for short residence times (less than eight days).
A few other conclusions of our study are given below:
The ponds' hydrodynamics has been studied and a mathematical model is now available If there is no stratification in the ponds, a thermal model can be proposed where the mean absolute difference is 0.7°C±0.2.
In the system under study, the contribution of algal biomass to the system is very small.
The effect of environmental conditions on faecal coliform decay in post-treatment of UASB reactor effluent
Authors: van der Steen P. , Brenner A. , Shabtai Y. , Oron G. 
Published: May 2018

The removal of faecal coliforms (FC) in waste stabilization ponds is partly caused by natural decay processes. This work distinguishes between light mediated and light independent processes, since only the upper layer of a stabilization pond receives solar radiation. Light attenuation by algae matter or other particles causes darkness in the rest of the pond. The purpose of this work was to investigate the decay processes in stabilization ponds in order to yield improved design of pond systems.
Experiments were carried out with buffered effluents from an Upflow Anaerobic Sludge Blanket (UASB) reactor, treating domestic wastewater. The FC decay rate was determined and compared for light and dark conditions, in aerated bottles and beakers, respectively. The effective environmental factors were also investigated and mathematical expressions were derived for their effect on the FC decay rate. Special attention was given to the effect of light attenuation by algae matter.
It was found that light independent FC decay in aerated UASB effluent is caused by a shortage in carbon sources, since glucose addition prevented decay for over ten days. The nutrient content of UASB effluent was satisfactory for a long-term survival. The FC decay in the dark parts of stabilization ponds is therefore under conditions of carbon and nutrient sufficiency expected to be negligible. Under conditions of carbon shortage, the light independent FC decay was found to be temperature dependent, but not pH dependent (in the range 7.2 - 9.1).
The FC decay in beakers exposed to solar radiation was much faster then under dark conditions. The light mediated decay was affected by the pH, DO concentration and the solar radiation intensity, but not by the temperature. The addition of autoclaved algae matter strongly reduced the FC decay in the beakers, due to light attenuation. It is therefore expected that the light attenuation by algae matter in stabilization ponds also reduces the FC decay. This could partly offset the stimulating effects of algae photosynthesis (i.e. increased pH and DO concentrations) on FC decay. It seems therefore that there is an optimum algae concentration for maximum FC decay. This can lead to a new design approach, based on regulation of algae growth in stabilization pond systems.
Characterisation of phosphorus in sediments from waste stabilization ponds
Authors: Gómez E. , Paing J. , Casellas C. , Picot B. 
Published: May 2018

The waste stabilization pond (WSP) systems are useful for the treatment of wastewater. Despite a good knowledge of these systems, the dynamics of phosphorus elimination in these systems are not well known, especially concerning the forms of phosphorus in the sediment.
Phosphorus dynamics were studied with data collected from the three stabilization ponds of the Mèze (France) system. A conceptual model based on theoretical considerations was developed, and applied to each pond. The percentage of observed variation described by these models ranged between 46.2% and 74.1%. The results showed that the principal variables affecting orthophosphate in WSP systems were phosphorus input and particulate phosphorus. When the model was applied to high rate algal pond (HRAP) data, the role of photosynthesis on pH increase and P precipitation was clear.
Sediments sampled in the three facultative ponds were characterised with a fractionation scheme, currently used for sediments of natural aquatic ecosystems. Inorganic phosphorus accounted for 92-94% of total sediment phosphorus, with 57–59% bound to iron hydroxides and 33–37% bound to calcium. Surprisingly, organic phosphorus represented only between 6 and 8%. Polyphosphate was detected. Phosphorus concentration was greatest in the sediment from the third pond, where an aerobic layer at the sediment surface prevented phosphorus release.