bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of nutrient input loading and riverine export fluxes in large watersheds
Authors: Hetling Leo J. , Jaworski Norbert A. , Garretson David J.
Published: May 2018

An input-output mass balance watershed model was developed and tested on ten large benchmark watersheds in the northeastern United States. Inputs of chlorides, sulfates, potassium, phosphorus, and nitrogen were calculated from published census data on population, wastewater discharges, land use, air emissions, agriculture, forestry, and transportation. Attenuation factors were selected for the inputs, (for example, air deposition, fertilizer, point source discharges) and the average annual riverine export flux for the watersheds was calculated for the period from 1900 to 1995. Historic chlorides, sulfates, potassium, phosphorus and nitrogen river export fluxes were independently calculated for each watershed using long term monitoring data obtained primarily from the USGS and public water supplies. A comparison of the attenuated watershed inputs and the monitored output river flux suggests that it is possible to obtain reasonable estimates of watershed export fluxes from existing landscape input data. The above methodology was applied to two major tributaries of the Hudson River and the results are described. Input-output models which can simulate long term historical changes in riverine fluxes based on inputs rather than on land use types will be useful for the development of effective and efficient nutrient control programs on a watershed basis.
Mussels as biomonitors of point and diffuse sources of trace metals in the clyde sea area, Scotland
Authors: Miller B. S.
Published: May 2018

Following a series of international conferences on pollution of the North Sea, the UK Government committed itself in 1990 to reducing the inputs of certain dangerous substances reaching the aqueous environment from point and diffuse sources. The target was a 50% reduction in loadings over the period 1985-95. Metals loadings from rivers and sewage works to the Clyde Sea Area are presented for the period 1990-97. These are compared to trace metals body burdens in mussels collected from shores throughout the Clyde Sea Area over the period 1980-97.

For most metals, no clear trend either increasing or decreasing was observed in metals loadings from point sources or in mussel body burdens. The exceptions were cadmium, which showed downward trends with time in loadings and in concentrations in Clyde Estuary mussels, and lead, which showed a downward trend in mussel concentrations.

Metals loadings from point sources may have reached baseline levels, below which further reductions will be difficult to achieve. Elevated mussel body burdens of specific metals provided good evidence that some shores are severely affected by point source inputs, others by bulk contamination from far-field point sources, and others by diffuse sources of metals.
The nonpoint source impacts of peri-urban settlements in South Africa: implications for their management
Authors: Pegram G. C. , Quibell G. , Hinsch M.
Published: May 2018

South Africa is currently experiencing rapid urbanization, much of which is in under-serviced and informal settlements. This has resulted in significant nonpoint source related water quality problems in these settlements. Although contamination of water resources is a physical process, which is related to the settlement character and service levels, the institutional and socio-economic conditions in the settlements largely govern its manageability. Understanding the settlement characteristics that exacerbate or mitigate water quality problems is therefore necessary for the identification and selection of appropriate management solutions. This paper outlines the key physical, institutional and socio-economic factors that contribute to water quality impacts from peri-urban settlements, and explores the implications of these characteristics for management of the nonpoint source impacts.
Development and implementation of a policy for reduced agrochemical and nutrient emission from the agriculture to surface water in the western part of the Netherlands
Authors: Mul M. I. , van der Vlies A. W.
Published: May 2018

The water authority “Hollandse Eilanden en Waarden” (HEW) is responsible for the quality of the surface water in the western region of The Netherlands. In this area the reduction of emissions of agrochemicals and nutrients from agriculture and horticulture to surface waters is one of the main priorities in the strategy to reduce the discharge from non-point sources. Because of the area and the relatively intensive use of chemicals for crop protection arable farming and the field production of vegetables are the major source of diffuse pollution by agrochemicals and nutrients in the management area of HEW. This paper gives an overview of the research programme carried out to investigate the different emission routes from arable farming and the field production of vegetables. Based on the results of this research programme a special programme “PAREL” was developed and implemented in 1997. The name PAREL (pearl in English) stands for ‘plan for reduction of emission from agriculture’. This plan was developed and implemented in close co-operation with the farmers' organizations. This initiative of HEW was accepted by the other water authorities in the western part of The Netherlands. For the implementation period a special treaty was signed in 1997 between the agricultural sector and these water authorities. The PAREL policy is a combination of regulation and advice (good housekeeping) aimed at reducing the emission of agrochemicals and nutrients to surface waters from agricultural activities.
Urban runoff pollution-summary thoughts - the state-of-practice today and for the 21st century
Authors: Roesner Larry A.
Published: May 2018

A number of papers at this conference were presented on quality aspects of urban runoff. In addition, three workshops addressed Urban Best Management Practices (BMPs), Highway Runoff, and Megacities in the 21st Century, respectively. Several well-known presenters expressed conflicting views on fundamental issues regarding BMP adequacy and the proper approach to urban runoff quality management. Upon reflection, the author believes that the conflicting opinions result principally from two related facts: 1) there is no accepted uniform design criteria for BMPs, so that various authors are comparing apples and oranges; and 2) the objectives of the management practices differ between authors. This paper responds to those conflicting views, with some reflections on the state-of-practice in the three subject areas, based upon some of the presentations in the conference sessions and in the workshops.
The Role of Advanced Treatment in Wastewater Reclamation and Reuse
Authors: Mujeriego Rafael , Asano Takashi
Published: May 2018

The role of advanced wastewater treatment in wastewater reclamation and reuse is reviewed. Most of the current wastewater reclamation and reuse technologies are essentially derived from those used in water and wastewater treatment. However, opportunities for adopting technological innovations are much greater for water reuse applications, because reclaimed water will have an economic value as an alternative water supply. Significant progress has been made in developing sound technical approaches to producing high quality and reliable water sources from reclaimed wastewater. This overview paper provides an assessment of technological advances in water reclamation and reuse, which has been dubbed as “the greatest challenge of the 21st century.” The paper was presented at the Opening Plenary Session of the IAWQ's Advanced Wastewater Treatment, Recycling and Reuse Conference in Milan, Italy on September 14, 1998.
Abel Wolman's “The Metabolism of Cities” Revisited: A Case for Water Recycling and Reuse
Authors: Hermanowicz Slawomir W. , Asano Takashi
Published: May 2018

Factors affecting the feasibility of water reclamation and reuse in an urban environment are discussed with special focus on reclaimed water quality and reuse applications. Water supplied to a city undergoes only small changes in quality and thus becomes a valuable resource ready for reuse and under local control. Successful development of water reuse must take into consideration technical, financial and social aspects. The quality of the reclaimed water must be matched to its intended use and alternative means of its distribution should be considered. Regional population growth patterns and their influence on economic feasibility of water reuse are examined.
Simultaneous Nitrification and Denitrification using SiporaxTM Packing
Authors: Menoud P. , Wong C. H. , Robinson H. A. , Farquhar A. , Barford J. P. , Barton G. W.
Published: May 2018

In this paper, we examine a biofilm process for simultaneous removal of ammonia and NOX (nitrite and nitrate). SiporaxTM, a porous Raschig-ring type filter specifically designed and manufactured for fast colonisation by micro-organisms, was used to demonstrate the feasibility of simultaneous nitrification (usually an aerobic process) and denitrification (usually an anaerobic or anoxic process) inside a single reactor. Clear evidence was found that denitrification occurred inside the internal pore structure of SiporaxTMrather than in an anoxic zone near the outlet of the reactor. The reactor was operated continuously and maximum nitrification and denitrification capacities of 0.61 and 0.83 g N/(1.day), respectively were observed in this study.
Residence Time Distribution and Disinfection of Secondary Effluents by Infiltration Percolation
Authors: Brissaud F. , Salgot M. , Bancolé A. , Campos C. , Folch M.
Published: May 2018

Infiltration percolation is used as a tertiary treatment in order to meet the WHO's microbiological standards applying to unrestricted agricultural wastewater reuse. Faecal coliform removal, Δfc, was investigated in laboratory columns and on a 565 m2 pilot plant. Δfc observed in laboratory columns was shown to be closely related to water detention time distribution, DTD. The relationship between Δfc and DTD, which has been determined from column tests, allowed a good prediction of the disinfection performances of the pilot plant for hydraulic loads of 0.54 and 0.66 m/d. For 0.82 m/d, the maximum load that could be tested on the plant, the mean faecal coliform removal was more than 1 log. unit higher than predicted. These unexpected good performances, though calling for more comprehensive explanation, speak for the widespreading of a reliable and cost-effective extensive technique.
Ultraviolet Disinefection of Secondary and Tertiary Effluent in the Mediterranean Region
Authors: Andreadakis A. , Mamais D. , Christoulas D. , Kabylafka S.
Published: May 2018

A study was undertaken to evaluate the efficiency of ultraviolet radiation in disinfecting secondary and tertiary effluents using wastewater from two full scale treatment plants located in the greater Athens area, the one receiving municipal sewage and the other receiving municipal sewage and septage. The effective UV dose for coliform removal, the effects of feedwater characteristics on UV disinfection and the lamp fouling potential were examined. For secondary effluent samples the required UV dose to achieve effluent fecal concentrations of less than 2,000 FC/100 ml varied from 30 to 60 mW-sec/cm2, depending on the water quality characteristics of the feedwater. High effluent suspended solids significantly increased the UV dose required to achieve adequate disinfection. For tertiary effluent the required UV dose to meet the 2000 FC/100 ml criterion was only 10 mW-sec/cm2, where as a dose of 40-50 mW-sec/cm2 was sufficient to achieve effluent coliform concentrations of less than 10 FC/100 ml. The inactivation of coliforms followed first order kinetics for relative low UV doses, with inactivation rates in the 0,107–0,303 cm2/mW-sec range for secondary effluent and 0,325 cm2/mW-sec for tertiary effluent. The lamp fouling potential was relatively high and the required lamp cleaning frequency was approximately twice per month.
Assessment of the Design Parameters for Wastewater Treatment by Reverse Osmosis
Authors: Van Gauwbergen D. , Baeyens J.
Published: May 2018

A modelling procedure is presented to predict the fluxes and solute concentrations in different flows for reverse osmosis (RO) spiral-wound modules. Important underlying factors for this procedure are the osmotic pressure for various solutions, the hydrodynamic flow profile in the concentrate channel, and the intrinsic separation characteristics of the membrane material. Experiments were carried out using a flat sheet test cell to determine the parameters of the mass transport model. Results of residence time distribution (RTD)-measurements on an industrial spiral-wound module were used to determine macroscopic fluid flow regimes resulting in the definition of dead volume fraction, average residence time and Pe-number. The evaluation of the modelling procedure has been based on experimental data of an industrial membrane plant system.
Replacement of Secondary Clarification by Membrane Separation—Results with Tubular, Plate and Hollow Fibre Modules
Authors: Günder Berthold , Krauth Karlheinz
Published: May 2018

Membrane separation systems can replace the final clarification step to separate mixed liquor suspended solids (MLSS) in the activated sludge processes. Mixed liquor suspended solids concentrations as high as 20 g/l can be obtained 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, solids free effluent qualities can be achieved with this process technology. This paper reports about the parallel investigation of three membrane systems installed within or outside bioreactors of 7 to 9 m3 volume and flow rates from 1 to 3 m3/h. The different membrane modules were investigated: plate module (80 m2 membrane surface), hollow fibre module (80 m2) and tubular module (45 m2). At MLSS concentrations up to 25 g/l and water temperatures from 10 to 25°C a stable operation of the membrane systems was achieved for a period of more than one year. The energy consumption was approximately 1.5 kWh/m3 for the plate and hollow fibre and 3.0 kWh/m3 for the tubular module system.
Optimization of Artificial Wetland Design for Removal of Indicator Microorganisms and Pathogenic Protozoa
Authors: Gerba C. P. , Thurston J. A. , Falabi J. A. , Watt P. M. , Karpiscak M. M.
Published: May 2018

The enhancement of water quality by artificial wetland systems is increasingly being employed throughout the world. Three wetlands were studied in Tucson, AZ to evaluate their individual performance in the removal of indicator bacteria (coliforms), coliphage, and enteric pathogens (Giardia and Cryptosporidium). A duckweed-covered pond, a multi-species subsurface flow (SSF) and a multi-species surface flow (SF) wetland were studied. Removal of the larger microorganisms, Giardia and Cryptosporidium, was the greatest in the duckweed pond at 98 and 89 percent, respectively. The lowest removal occurred in the SF wetland, 73 percent for Giardia and 58 percent removal for Cryptosporidium. In contrast, the greatest removal of coliphage, total and fecal coliforms occurred in the SSF wetland, 95, 99, and 98 percent respectively, whereas the pond had the lowest removals (40, 62, and 61 percent, respectively). Sedimentation may be the primary removal mechanism within the duckweed pond since the removal was related to size, removal of the largest organisms being the greatest. However, the smaller microorganisms were removed more efficiently in the SSF wetland, which may be related to the large surface area available for adsorption and filtration. This study suggests that in order to achieve the highest treatment level of secondary unchlorinated wastewater, a combination of aquatic ponds and subsurface flow wetlands may be necessary.
Behavior and Characterization of Residual Organic Compounds in Wastewater Used for Indirect Potable Reuse
Authors: Drewes Jörg E. , Fox Peter
Published: May 2018

The scope of this study was to compare the behavior and character of dissolved organic carbon (DOC) during soil-aquifer treatment at different field sites in Arizona and California. To determine biodegradable and residual organic carbon, biodegradability studies using batch tests and a laboratory soil-column system were examined, combined with additional examinations for further characterization (ultrafiltration, adsorption analysis). Based on this comparison, soil-columns in series seemed to be more appropriate to simulate SAT as compared to batch-tests since this test system indicated continuous structural changes of generally poorly degradable organic compounds during SAT. This ongoing change of organic matter was confirmed by field measurements indicating biodegradation as the dominant removal process for DOC during SAT. The level of residual DOC after short-term SAT was similar although wastewater treatment processes differed at the investigated sites. However, increasing source water DOC led to an increase of residual DOC. In general, source water quality, drinking water and wastewater treatment should be viewed as one system in indirect potable reuse projects.
Degradation of Membrane Concentrates of the Textile Industry by Fenton Like Reactions in Iron-Free Solutions at Biocompatible pH Values (pH ≈ 7–8)
Authors: Balanosky E. , Fernandez J. , Kiwi J. , Lopez A.
Published: May 2018

Degradative oxidation of membrane concentrates of textile waters were carried out in batch reactors in the dark and under visible light. H2O2 and Nafion-Fe3+/H2O2 as an immobilized Fenton reagent were used as ecological oxidants. The results observed with the Nafion/Fe3+ system lead to a kinetically faster and more complete oxidation than H2O2 alone and comparable to the homogeneous Fenton reaction in solution. This study reports on the Fenton treatment of membrane concentrates resulting from nanofiltration of biologically treated secondary textile effluents produced in a large scale in Northern Italy. The degradation of the membrane concentrates is accelerated under light due to the recycling of the Fe3+-ion in the Nafion avoiding the drawbacks of the homogeneous treatment. A reduction of ∼ 50% is seen in the TOC and of ∼20–50% in optical absorbance after 3 hours pretreatment under light for end of pipe membrane concentrates under light and the process was stable over many cycles. The observed degradation depended on the amount of H2O2, the intensity of the visible light applied. But it varied very little on the pretreatment pH which makes the Fenton immobilized systems suitable to pretreat membrane concentrates up to pH 8. The membrane concentrates showed a decrease in their toxicology when undergoing oxidative pretreatment under visible light mediated by Nafion-Fe3+ (1.78%) adding in solution H2O2 (10 mM). Mathematical modeling of the degradation parameters is presented by constructing a single exponential polynomial function.
Concepts and methodologies to minimize pollutant discharge for zero-emission production
Authors: Hu Hong-Ying , Goto Naohiro , Fujie Koichi
Published: May 2018

The present study aims to present basic concepts to minimize the emissions from industrial production processes. Strategies and methodologies to analyze emissions from various production processes, to establish a so called negative flow sheet and to reduce the emissions from those processes by refining and/or replacing the present production process with an alternative process are discussed. Preliminary evaluation and management systems of the materials used in the production process based on characteristics such as microbial and physico-chemical treatabilities are proposed as well. The relationship between the removal efficiency of dissolved organic carbon in the five-days BOD test and that in a laboratory scale submerged biofilter with continuous operation is suggested to evaluate the biological removability of organic pollutants contained in wastewater. A novel concept to select the appropriate treatment process of an industrial wastewater based on properties such as the molecular size and biodegradability of the pollutants contained in that wastewater is also proposed. To give basic information for the minimization of energy consumption in wastewater treatment, various biological wastewater treatment processes are compared from the view point of power economy.
The effects of contaminated sediments of the Blesbok Spruit near Witbank on water quality and the toxicity thereof to Daphnia pulex
Authors: Hill Liesl , Jooste Sebastian
Published: May 2018

With the increasing focus on environmental issues, the objective of this study is to evaluate the potential impact of contaminated sediments of the Blesbok Spruit near Witbank - which receives acid mine drainage (AMD) inter alia - on biota. Direct transfer of chemicals from sediments to organisms is considered to be a major route of exposure for many species, and therefore focusing attention on sediment contamination and highlighting the fact that sediments are an important resource. Acute toxicity tests were performed on Daphnia pulex using both extracted sediment interstitial water and surface water. Chemical analyses were also performed on the sediment, interstitial water and surface water samples. The toxicity results suggest that metal toxicity adds significantly to the toxicity of the stream water which is enhanced by the effect of pH. The pH of the stream and interstitial water was consistently below 4.5.
The use of granular activated carbon for the treatment of impounded surface water
Authors: Pryor M. J. , Nozaic D. , Freese S. D. , Rajagopaul R.
Published: May 2018

Increased levels of nutrients and pollutants are expected in the Inanda Dam (KwaZulu Natal, South Africa) as a result of wastewater effluent discharge, informal settlements and agricultural runoff in the catchment. Contaminants of atrazine and 2-methyl isoborneol were dosed into the feed water of a granular activated carbon (GAC) pilot plant to assess the performance of different process options for the treatment of Inanda Dam water. It was found that the use of ozonation and GAC did not result in increased levels of biological activity as expected. The use of ozone in conjunction with GAC is however recommended as significant benefit was obtained in the reduction of UV absorbance, chlorine demand and concentrations of other microcontaminants.
Production of biodegradable plastics from chemical wastewater - a novel method to reduce excess activated sludge generated from industrial wastewater treatment
Authors: Chua H. , Yu P. H. F.
Published: May 2018

Biological polymers produced by microbial fermentation are naturally biodegradable and are potential environment-friendly substitutes for synthetic plastics. However, broader applications are restricted by high production costs. In this study, activated sludge bacteria in a conventional system treating a wastewater that contained xenobiotic organics were induced by nitrogen deficiency in the reactor liquor to accumulate intracellular storage polymers, which can be extracted as a low-cost source of biodegradable plastics. Chromatographic analysis of the extracted polymers revealed a composition of poly-hydroxyalkanoate and a number of related co-polymers. Alcaligene spp. in the activated sludge microbial consortium was identified as the main genus that accumulated these polymers. When the C:N ratio was increased from 20 to 140, specific polymer yield increased to a maximum of 0.39 g polymer/g dry cell while specific growth yield decreased to 0.26 g dry cell/g carbonaceous matter consumed. The highest overall polymer production yield of 0.11 g polymer/g carbonaceous matter consumed was achieved when the C:N ratio was maintained at a nitrogen- deficient level of 100. The specific polymer yield in the isolated Alcaligene spp. cells reached as high as 0.7 g polymer/g dry cell mass. While reducing the costs of biodegradable plastics, this technique also reduced the amount of excess sludge generated from the wastewater treatment process by 39%.
Health risk assessment of groundwater contaminated with methyl tertiary butyl ether (MTBE)
Authors: Hartley W. R. , Englande A. J. , Harrington D. J.
Published: May 2018

Methyl tertiary butyl ether (MTBE), a volatile oxygenate commonly used in fuels, is a frequent contaminant of some shallow groundwater. Based on limited reporting, concentrations of MTBE in drinking water were generally less than 10 μg/L but excursions up to 770 μg/L have been reported. Based on current MTBE toxicological data with emphasis on carcinogenic potential, and reproductive and developmental effects, a maximum drinking water level of 100 μg MTBE/L is suggested. This recommended advisory level takes into consideration the equivocal evidence of the carcinogenicity of MTBE in humans and low potency in an oral exposure animal study. Definitive conclusions regarding health risks to the general population from MTBE contamination of drinking water are not possible due to a paucity of monitoring data. There is increased evidence of contamination of storm water and shallow groundwater from primarily, nonpoint sources. Considering MTBE mobility and stability in water, movement to deep groundwater and drinking water supplies seems probable. In light of projected increased MTBE use, there is a need for a more rigorous monitoring program to define the frequency of MTBE contamination of drinking water supplies and to develop risk management policies.
Industrial Ecology of the Paper Industry
Authors: Pento Tapio
Published: May 2018

Industrial ecology (IE) is a biological concept applied to industrial structures. The basic concepts of IE include regional, intra-firm and product-based waste recycling systems as well as the principle of upward and downward cascading. In best current examples of regional systems, several parties are in an industrial waste re-use symbiosis. Paper industry has learned to arrange the recovery and re-use of its products on distant markets, even up to a level where indications of exceeding optimal recovery and re-use rates already exist through deteriorated fibre and product quality. Such occurrences will take place in certain legislative-economic situations. Paper industry has many cascade levels, each with their internal recovery and recycling, as well as many intra-firm, regional, and life cycle ecology structures. As an example of prospects for individual cascading routes, sludges may continue to be incinerated, but the route to landfills will be closed. The main obstacles of legislative drive toward better IE systems are in many cases existing laws and political considerations rather than economic or technical aspects. The study and practice of engineering human technology systems and related elements of natural systems should develop in such a way that they provide quality of life by actively managing the dynamics of relevant systems to reduce the risk and scale of undesirable behavior and outcomes. For the paper industry, earth systems engineering offers several development routes. One of them is the further recognition of and research on the fact that the products of the industry are returned back to the carbon cycle of the natural environment. Opportunities for modifying current earth systems may also be available for the industry, e.g. genetically modified plants for raw materials or organisms for making good quality pulp out of current raw materials. It is to be recognized that earth systems engineering may become a very controversial area, and that very diverse political pressures may determine its future usefulness to the paper industry.
Upgrading of an Activated Sludge Plant with Floating Biofilm Carriers at Frantschach Swiecie S.A. to Meet the New Demands of Year 2000
Authors: Hansen Eva , Zadura Leszek , Frankowski Stefan , Wachowicz Marian
Published: May 2018

Frantschach Swiecie S.A., the largest Pulp & Paper producer in Poland and one of the larger in Europe, chose to upgrade the existing WWTP with a new floating biological bed equipped with an advanced steering system. The discharge from the WWTP will be one of the lowest in Europe, 4 kg COD/tonne produced pulp, and is already below the future goals for the European Union. The new demands have been reached with an advanced steering system controlling three selective biological reactors operating in series and/or parallel. Each biological reactor is operating at specific conditions to decrease selected organic compounds. The new floating biological bed, FlooBed®, is an upgraded activated sludge system with floating carriers covered with a thin biological film. The FlooBed® reactor is a progress from fluidised beds and modified activated sludge plants.

The activated sludge plant as such has not been rebuilt. The improvement of the activated sludge process is that the wastewater now is saturated with oxygen and new micro-organisms are created before the entry to the existing activated sludge plant.

The FlooBed® reactors are installed in a volume that is 50 % of the former activated sludge plant volume and the reduction of COD has increased from 51 to 90 %. The operational costs for the FlooBed® are 17 EUR/tonne reduced COD where 7 EUR is electricity and the remaining part is added chemicals.
Chemical Degradation of EDTA and DTPA in a Totally Chlorine Free (TCF) Effluent
Authors: Rodríguez J. B. , Mutis A. , Yeber M. C. , Freer J. , Baeza J. , Mansilla H. D.
Published: May 2018

In this work, a synthetic TCF effluent containing vanillin, glyoxal, sodium formate, sodium acetate and the chelanting agents EDTA and DTPA was treated using, O3, O3/H2O2, O3/UV, UV, UV/H2O2 and UV/H2O2/O3 at pH 7 and 11. The best results were obtained in the O3/UV process. Ozone alone did not degrade EDTA neither DTPA. A combined O3/UV (pH 7.0 by 15 min)-biological treatment was very efficient in the removal of the chelants (98 %) and COD (95 %).
Toxicity Abatement and Biodegradability Enhancement of Pulp Mill Bleaching Effluent by Advanced Chemical Oxidation
Authors: Yeber Ma Cristina , Rodríguez Jaime , Baeza Jaime , Freer Juanita , Zaror Claudio , Durán Nelson , Mansilla Héctor D.
Published: May 2018

This paper describes the use of photocatalysis to degrade two bleaching effluents from P. radiata (DoEop) and E. grandis (CEop) wood processing. Organic matter oxidation was followed by general parameters (TOC, color, AOX), toxicity and biodegradability. Reactions with suspended and supported catalysts, TiO2 and ZnO, were carried out for comparison. For both effluents, photocatalytic treatment led to an improvement in biodegradability and a reduction in acute toxicity.
Pulp Mill Effluent Treatment by Fenton-Type Reactions Catalyzed by Iron Complexes
Authors: Rodríguez Jaime , Contreras David , Parra Carolina , Freer Juanita , Baeza Jaime , Durán Nelson
Published: May 2018

Fenton reaction, which involves hydrogen peroxide and ferrous ion, has been proposed as an efficient option for effluent treatment. In this work, the treatment of a pulp bleaching effluent using Fenton-type reactions assisted by either, 2,3-dihydroxybenzoic acid (2,3-DHBA), 3,4-dihydroxybenzoic acid (3,4-DHBA) and 1,2-dihydroxybenzene (CAT), were studied. The treatment was evaluated by the removal of adsorbable organochloride compounds (AOX) and toxicity. Furthermore, the degradation of 2-chlorophenol and 4-chlorophenol in aqueous solutions were carried out, separately. Increase in oxidative activities of Fenton-type reactions mediated by the dihydroxybenzenes (DHBs) were found. These activities enhancement were related with a higher production of activated species by Fe/DHBs/H2O2, as indicted by chemiluminesce. The large decrease in AOX values and toxicity of the treated bleaching effluent by DHBs at pH 4.0 and 7.0 showed that 2,3-DHBA enhanced the activity of the Fenton reaction. The use of 3,4-DHBA and CAT resulted in loss of efficiencies of Fenton reaction to effluent treatment but not to pure chlorophenol solutions. At pH 7.0 lower efficiencies than those at pH 4.0 were achieved.
Small municipal wastewater treatment plants in Greece
Authors: Tsagarakis K.P. , Mara D.D. , Horan N.J. , Angelakis A.N.
Published: May 2018

Data from 147 small municipal wastewater treatment plants (MWTP), with a population equivalent (p.e.) less than 10,000, have been collected and analysed. Extended aeration plants are the most common (75%), followed by natural systems - waste stabilisation ponds (9%) and hydroponic silviculture (6%). Only 71 MWTP (out of the 147) were operational in 1997; the performance of only 15 of these was good, for 36 was moderate and for 20 it was poor. It was found that the reasons for poor performance, for the plant failure and for delays in commissioning were managerial and institutional, rather than purely technical.
Treatment of wastewater by constructed wetland in small settlements
Authors: Ayaz S.Ç. , Akca I.
Published: May 2018

The constructed wetland is a low-cost technology to control environmental pollution. The system is especially suitable for small settlements. An innovative constructed wetland technology is described in this paper. A pilot plant was used to assess the performance of the system. The experimental system consists of two serial connected tanks that settled up with fillers and Cyperus as treatment media. Wastewater is recycled periodically upward and downward between the two tanks. The treatment performance was monitored in different loading conditions in a one-year period. The average COD removal efficiency of 90% was observed at 122 g COD/m2.day average loading conditions. Other average removal values in the same conditions are as follows: suspended solid 95%, TKN 77%, total nitrogen 61%, PO4-P 39%. The land requirement for this system will be 0.82 m2 per capita when applying as full-scale system.
Upgrading of wastewater treatment plants equipped with rotating biological contactors to nitrification and P removal
Authors: Nowak O.
Published: May 2018

In the course of a research project on the further use of treatment plants with rotating biological contactors for nitrification and phosphorus removal, full-scale investigations were carried out. From the results design parameters for phosphorus pre-precipitation as well as for secondary and tertiary nitrifying RBCs were derived. Regarding the impact of the oxygen concentration, the alkalinity and the pH, respectively, on nitrifying biofilms, former research work could mostly be confirmed. Concepts for the upgrading of different types of RBC plants are discussed - including cost estimations.
Heating up trickling filters to tackle cold weather conditions
Authors: Gebert W. , Wilderer P.A.
Published: May 2018

The investigated effects of heating the filling material in trickling filters were carried out at the Ingolstadt wastewater treatment plant, Germany. Two pilot scale trickling filters were set up. Heat exchanger pipings were embedded in the filter media of one of these trickling filters, and the temperature in the trickling filter was raised. The other trickling filter was operated under normal temperature conditions, and was used as a control. The results clearly demonstrate that the performance of trickling filters cannot be constantly improved by heating the biofilm support media. A sustained increase of the metabolic rates did not occur. The decrease of the solubility of oxgen in water and mass transfer limitations caused by an increase of the biofilm thickness are the main reasons for that. Thus, the heating of trickling filters (e.g. by waste heat utilization) in order to increase the capacity of trickling filters under cold weather conditions cannot be recommended.
Upgrading of a small wastewater treatment plant in a cold climate region using a moving bed biofilm reactor (MBBR) system
Authors: Andreottola G. , Foladori P. , Ragazzi M.
Published: May 2018

The aim of this study was to evaluate the performance of a full-scale upgrading of an existing RBC wastewater treatment plant with a MBBR (Moving Bed Biofilm Reactor) system, installed in a tank previously used for sludge aerobic digestion. The full-scale plant is located in a mountain resort in the North-East of Italy. Due to the fact that the people varied during the year's seasons (2000 resident people and 2000 tourists) the RBC system was insufficient to meet the effluent standards. The MBBR applied system consists of the FLOCOR-RMP®plastic media with a specific surface area of about 160 m2/m3 (internal surface only). Nitrogen and carbon removal from wastewater was investigated over a 1-year period, with two different plant lay-outs: one-stage (only MBBR) and two stage system (MBBR and rotating biological contactors in series). The systems have been operated at low temperature (5–15°C). 50% of the MBBR volume (V=79 m3) was filled. The organic and ammonium loads were in the average 7.9 gCOD m−2 d−1 and 0.9 g NH4−N m−2 d−1. Typical carbon and nitrogen removals in MBBR at temperature lower than 8°C were respectively 73% and 72%.
Fixed bed biological aerated filtration for secondary effluent polishing-effect of filtration rate on nitrifying biological activity distribution
Authors: Wijeyekoon S. , Mino T. , Satoh H. , Matsuo T.
Published: May 2018

Three fixed bed downflow biological aerated filters were operated at the rates of 5, 10 and 20 m/day under tertiary treatment conditions. A high NH4+−N oxidation rate of 1.75 kg−N/m3 /day was achieved with an effective residence time of 15 minutes. The biofilm biomass density increased with increasing load while the density gradient along the filter bed became narrower with higher filtration rate. Specific biological activity was inversely proportional to the biomass density. Specific overall biological activity and specific nitrifying activity were found to be higher towards the effluent end of filters operated at the rates of 20 and 10 m/day whereas the highest specific nitrification activity was found to be at the feed end of the slowest filter. Introduction of easily biodegradable organic substrate affected the nitrification activity in the slower filters. The above findings suggest that the location of concentrated nitrification activity is filtration rate dependent. Presence of nitrifiers close to the feed end in a fixed bed downflow filter could be a disadvantage in the presence of faster growing heterotrophic activity under influent fluctuating conditions.
Membrane bioreactors for use in small wastewater treatment plants: membrane materials and effluent quality
Authors: Gander M.A. , Jefferson B. , Judd S.J.
Published: May 2018

The relative efficiencies of three membrane materials for use in a submerged membrane bioreactor treating domestic wastewater were evaluated. A glass-filled hydrophobic polypropylene membrane allowed no flow through the membrane. A polysulphone membrane (PS, 0.4 mm pore size) did not achieve a steady-state flux although a flux of 7 l m−2h−1 occurred on the last day of the steady-state run. A melt-blown polypropylene membrane (NWPP, 5 μm pore size) gave a steady-state flux of 5 l m−2h−1. Membrane productivity was low due to irreversible fouling in the NWPP membrane and reversible fouling in the PS membrane. It was found that the PP membrane gave a 5-log reduction in total coliforms whereas the PS membrane gave a 9-log reduction. CBOD5, COD, SS, NH3-N and turbidity removal was similar with both the PS and the NWPP membranes. It was concluded that although the NWPP membrane was relatively inexpensive and achieved a high degree of organic matter removal, due to its inability to remove bacteria from the effluent it would be inappropriate to apply it to domestic wastewater in a submerged MBR.
Treatment of landfill leachates by comparing advanced oxidation and coagulation-flocculation processes coupled with activated carbon adsorption
Authors: Ramíirez Zamora R.M. , Durán Moreno A. , Ortade Velásquez M.T. , Monje Ramírez I.
Published: May 2018

This work compares two pre-treatments (coagulation-flocculation process (CF) and the Fenton oxidation Method (FE)) of the activated carbon adsorption process (AC) to optimize the removal of the organic compounds in landfill leachates. The content of organic compounds was measured in terms of three global parameters: colour, chemical oxygen demand (COD) and dissolved organic carbon (DOC). The result obtained in discontinuous reactor conditions showed an increase in colour removal from 1.5 to 2.0 times and a decrease of COD between 0.3 to 0.5 times for the FE-AC treatment, in relation to the CF-AC treatment. On the other hand, the data obtained in continuous reactor conditions (packed columns) showed that the column fed with leachate CF exhibited operation times 1.3 times longer and a better physiochemical quality in the filtrate (COD and colour) than the one fed with the FE leachate. Nevertheless, the adsorption capacities in the colour removal column of COD and DOC were higher for the FE leachate.
Phosphorus removal in domestic wastewater using anaerobic fixed beds packied with iron contactors
Authors: Choung Y.K. , Jeon S.J.
Published: May 2018

The objective of this study is to develop an alternative phosphorus removal system for small-scale plants disposing domestic wastewater. In order to promote anaerobic microbial corrosion by sulfate reducing bacteria (SRB), a bench-scale upflow anaerobic fixed bed (UAFB) packed with iron contactors was installed, and operated to investigate the treatment characteristics of domestic wastewater from an apartment complex. It was found that there is a linear relationship between anaerobic corrosion and sulfate reduction by SRB within the range of operational conditions. As the results of introducing the UAFBs prior to an anoxic/oxic process, phosphorus removal efficiencies were enhanced with no adverse effects on nitrification and denitrification.
Environmental engineering education - summary report of the 1st European Seminar
Authors: Alha K. , Holliger C. , Larsen B. S. , Purcell P. , Rauch W.
Published: May 2018

This paper summarizes the discussions of the 1st European Seminar on Environmental Engineering Education (E3), which was held at EAWAG, Zurich, Switzerland in August 1999. Although the emerging discipline of environmental engineering, which was once viewed as being a sub-set of civil or chemical engineering, has established a status in its own right, a definition of environmental engineering is still not agreed among European engineering educators. This report discusses the variation between European countries and the way in which higher education institutions in these countries address the educational needs of environmental engineers. A review of the acceptance of this new discipline by employers and the status of environmental engineering as a profession throughout Europe is presented. The question of how to achieve greater compatibility and comparability of the systems of environmental engineering education in Europe is addressed and some objectives are identified in order to overcome the present difficulties.
Effect of particle size and sodium ion concentration on anaerobic thermophilic food waste digestion
Authors: Kim I.S. , Kim D.H. , Hyun S-H.
Published: May 2018

Serial basic tests were conducted for the determination of fundamental kinetics and for the actual application of kinetic parameters to food waste digestion with precise measurement of methane production. The effects of food particle size and sodium ion concentration on the anaerobic thermophilic food waste digestion process were investigated. Results of serial tests for the determination of fundamental kinetic coefficients showed the value of k (maximum substrate utilization rate coefficient) and KS (half-saturation coefficient) as 0.24 hr−1 and 700 mg/L, respectively, for non-inhibiting organic loading range. The substrate inhibition coefficient (Ki) was 1000 mg/L for inhibiting organic loading range. No inhibition effect was shown until 5g/L of sodium ion concentration was applied to the serum bottle reactor. However, the volume of methane gas was decreased gradually to the concentrations of more than 5 g/L of sodium ion applied. All sizes of food waste particle had the same constants (A:0.45) but the maximum substrate utilization rate constant (kHA) was inversely proportional to particle size. As average particle size increased from 1.02 mm to 2.14 mm, kHA decreased from 0.0033 hr−1 to 0.0015 hr−1. Result reveals that particle size is one of the most important factors in anaerobic food waste digestion.
Bench-scale anaerobic bioconversion of newsprint and office paper
Authors: Clarkson W.W. , Xiao X.
Published: May 2018

Anaerobic bioconversion of newsprint and waste office paper was performed in bench-scale reactors with three inocula sources: landfill, rumen, and anaerobic digester. Office paper bioconversion was nearly complete within 20 days but continued for about 165 days with methane yield efficiencies ranging from 71–85% of potential chemical oxygen demand (COD) conversion. Average newsprint methane conversion efficiencies ranged from 32–41% of total COD under strictly anaerobic conditions for 300 days. Mass balance calculations revealed that more than 80% of newsprint cellulose was biodegraded. The apparent limiting factor for anaerobic bioconversion of newsprint was the physical association between lignin and cellulose. After proper acclimation, the three inocula tested equally well for methane production under strictly anaerobic conditions. Testing of ground, shredded strips, and whole paper pieces showed no effects of feedstock size on bioconversion rate or extent. Alkali pretreatment with NaOH concentration up to 10% significantly improved newsprint biodegradability. Treatment for longer duration or at elevated temperatures increased the solubilization of lignin, but did not improve bioconversion of newsprint to methane. Neutralizing treated samples with carbon dioxide gave higher methane yields compared to sulfuric or hydrochloric acids, suggesting that digester neutralization could be combined with biogas scrubbing.
Increase of anaerobic degradation of particulate organic matter in full-scale biogas plants by mechanical maceration
Authors: Hartmann H. , Angelidaki I. , Ahring B.K.
Published: May 2018

Different concepts of implementation of mechanical pretreatment for enhancing the biogas potential from fibers in manure feedstock were valuated by sampling before and after macerators at different biogas plants and from a fiber separation unit. An increase of the biogas potential of up to 25% by pretreatment of the whole feed in the macerator before the reactor was observed. Implementation concepts with a treatment of the fibers alone after separation from the manure showed to be not efficient due to a low recovery of organic matter in the fibers by the separation unit. The low operational costs of a macerator make it attractive to use this pretreatment method for a more complete degradation of particulate organic matter. Investigation of the size distribution of the fibers showed that a change in biogas potential was not correlated to a smaller size of the fibers. Results from the macerators indicate that the biodegradability of the fibers is rather enhanced by shearing which is not necessarily reflected by a change in fiber size.