bluuebunny/crossref_metadata_2025 huggingface dataset:
Pollution by phosphorus and nitrogen in water streams feeding the Zelivka drinking water reservoir
Authors: Holas Jiri , Holas Marketa , Chour Vladimir
Published: May 2018

This case study refers to long term monitoring of Martinicky and Sedlický Brooks, which represent general water-quality characteristics well related to the watershed of the whole Zelivka drinking water reservoir. For a period of more than ten years water-quality indices were systematically monitored at each profile together with actual discharges recorded at selected profiles. It is seen that the only critical pollutants are nutrients, namely nitrate nitrogen and total phosphorus, originating from both urban and agricultural sources, while industrial pollution is relatively marginal in the watershed. Phosphorus concentrations do not display any simple time regularity. Persistent all-year background phosphorus load gives evidence of the urban origin of pollution. Total input of phosphorus into the reservoir came mainly from surface inflows, out of rainfall and out of bottom sediments. Phosphorus was found to be the limiting nutrient for phytoplankton growth and was therefore recognised as the principal element responsible for reservoir eutrophication rates, which could probably be effectively controlled by concerted abatement actions. Most of the watershed born nitrogen pollution has a distinctly non-point (diffuse) character. Typical yearly pattern of nitrate concentrations means distinct and regular increase during end-of-winter and spring period due to processes of mineralization, typical for productive arable land on soils with good drainage properties. The process of state economy transition, which was initiated in 1989, has led to dramatic decrease of fertiliser inputs per hectare of land. Reduced fertilisation of arable land has not yet been reflected in improved quality of surface waters.

The proposed strategy for prevention and abatement in the Zelivka reservoir eutrophication should be based on win-win principles applied throughout the entire watershed and, at present, preferentially focused on:phosphorus cycle control and improvement within both the watershed and reservoir water (diminished use of chemicals producing reactive phosphorus compounds, improved phosphorus removal from urban waste water, to prevent phosphorus release from bottom sediments)general soil erosion control and prevention - grassland cultivation on vulnerable areas and buffer zones and subsidy for cultivating plants on arable land even between growing periodsproper maintenance and improvement of treatment plant technology to maintain actual standards of produced drinking water.
Developing a new regulatory paradigm to address the impacts of diffuse pollution attributable to agriculture
Authors: McNitt Jan , Kepford Ron
Published: May 2018

To control pollution attributable to livestock operations, the statutory and regulatory scheme of the US Clean Water Act focuses on implementing structural controls to contain animal waste. While the United States Environmental Protection Agency (USEPA) is empowered only to regulate point sources, existing authority may be extended to regulate diffuse runoff associated with certain livestock facilities. Current water pollution abatement programs, however, have not responded to the differences inherent in diffuse pollution and the land management strategies necessary to control and abate its impacts. The Planned Intervention Micro-watershed Approach (PIMA) recognizes this distinction, offering a method of refining land management strategies while keeping existing point source pollution regulation and enforcement mechanisms in place. Within a limited time frame, producers have flexibility to develop and implement cost-effective management practices that achieve environmental goals. Planned intervention is integrated with a micro-watershed approach to watershed management which uses small, hydrologically discrete areas to target diffuse pollution sources and direct intervention efforts. This approach utilizes local stakeholder input and participation to create a bottom-up, community-based institutional framework for addressing diffuse pollution from agricultural sources that satisfies water quality objectives.
Nitrogen Removal in Fixed-Bed Submerged Biofilters without Backwashing
Authors: Canziani R. , Vismara R. , Basilico D. , Zinni L.
Published: May 2018

The paper reports the findings of four years of pilot-scale research on nitrogen removal in fixed-bed biofilters fed on real raw municipal wastewater. The plant was made of two fixed-bed biofilm reactors in series with an intermediate settling tank from which excess biomass from the first stage was discharged. The first filter was used for carbon removal either with oxygen or nitrates. The second filter was used for nitrification. The average nitrification rate at 20°C was 0.84 gNH4+-N m−2d−1 with 5 mg l−1 dissolved oxygen in the bulk liquid. Temperature dependence was calculated (rn = rn,20° 1,05T-20). The influent organic load strongly affected ammonia oxidation. If the organic loading exceeded 2.5 gCOD m−2 d−1 nitrification rate was reduced by 50%. Denitrification was performed by recycling nitrates back from the second filter and by using sewage itself as carbon source. Denitrification rate showed to be strongly dependent on temperature (rd = rd,20° 1.11T-20) and on the recycle rate. Hydrolysis of the colloidal COD fraction showed a similar dependence on both temperature and recycle rate. Therefore, it has been concluded that the hydrolysis of finely dispersed COD particles can be the limiting step of denitrification in the biofilter when real sewage is used as carbon source.
Elimination of Phosphorus from Municipal and Industrial Waste Water
Authors: Donnert Dietfried , Salecker Manfred
Published: May 2018

Application of the precipitation process using Fe and Al salts or lime, which is the main process used in Germany for phosphorus removal may lead to problems, such as an increase of the anion concentration of the water and recovering the phosphorus from the precipitation sludge. Therefore two processes for phosphorus removal from waste waters were developed which avoid these disadvantages:A process especially suitable for low phosphorus concentrations (≤1 mg/L P) employing Activated Alumina for the removal of the phosphate by adsorption.Phosphorus removal by means of direct precipitation of calcium phosphate induced by calcite as seeding material for the treatment of higher concentrated waters (≥20 mg/L P).
Environmental economics in the chemical processes industry
Authors: Roos Gina
Published: May 2018

Business is increasingly being held accountable for the social and environmental implications of its activities. Managing these diverse interactions can be very complex. Environmental economics is an approach to reconciling financial objectives with social responsibilities. It describes techniques for capturing a monetary value for the environment and therefore, a monetary value for impacts on the environment. In this way, environmental considerations are brought into perspective for business. Another tool that is used for integrating environmental considerations in business decisions is multi-criteria assessment. The difference between these two tools is illustrated when business makes the transition from a qualitative approach (considering environmental impacts) to a quantitative one (financially accounting for environmental impacts). Policy-makers concerned with the management of natural resources are increasingly causing businesses to make this transition through the use of economic instruments. This paper discusses how environmental economics can be used to bridge the traditional separation of economic and environmental considerations. Reference is made to international experience in the chemical processing industry.
Environmental pollution caused by a non-ferrous metal smelter
Authors: Hajdú A. , Licskó I.
Published: May 2018

After 80 years of operation health authorities have closed down a plant processing non-ferrous scrap metals. The ruling had both beneficial and adverse environmental impacts. The benefits include elimination of direct air pollution by metal compound emissions, but the metal-bearing dust deposited over 80 years and stirred up by winds is still a source of indirect pollution. Remediation involves partial soil replacement in residential areas in combination with covering, recultivating the 200 000 ton slag heap on the basis of detailed investigations. The adverse impact consists of the discontinuation of organized collection, break-up and processing of used car batteries. The rash, unfounded decision resulted in cases of heavy lead poisoning.
Waste minimization program in Shuaiba Industrial Area
Authors: Al-Muzaini Saleh
Published: May 2018

The Shuaiba Industrial Area (SIA) is located about 50 km south of Kuwait City. It accommodates most of the large-scale industries in Kuwait. The total area of the SIA (both eastern and western sectors) is about 22.98 million m2. Fifteen plants are located in the eastern sector and 23 in the western sector, including two petrochemical companies, three refineries, two power plants, a melamine company, an industrial gas corporation, a paper products company and, two steam electricity generating stations, in addition to several other industries. Therefore, only 30 percent of the land in the SIA's eastern sector and 70 percent of land in the SIA's western sector is available for future expansion.

Presently, industries in the SIA generate approximately 204,000 t of solid waste. With future development in the industries in the SIA, the estimated quantities will reach 240,000 t.

The Shuaiba Area Authority (SAA), a governmental regulatory body responsible for planning and development in the SIA, has recognized the problem of solid waste and has developed an industrial waste minimization program. This program would help to reduce the quantity of waste generated within the SIA and thereby reduce the cost of waste management.

This paper presents a description of the waste minimization program and how it is to be implemented by major petroleum companies. The protocols employed in the waste minimization program are detailed.
PISCES: power industry integrated systems, chemical emissions study
Authors: Gore B. J. , Gericke G. , Delport W.
Published: May 2018

Power industry chemical emissions study (PISCES) is a broad based study conducted by EPRI in the USA with input from utilities in the USA and other parts of the world. It aims to define the source, distribution, composition and fate of toxics in power plant process and waste streams. Eskom is partaking in this project to develop knowledge of trace element emissions from the power stations which will provide Eskom with sufficient information to determine the concentration levels of toxic trace element emissions from the power stations. From this, the fate of these emissions and their impacts on the environment can be determined. This paper is a report on the first sampling project conducted in South Africa at one of Eskom's power stations. The total study will involve sampling at other power stations and a risk analysis of the fate of the toxic elements emitted. This total study will be completed in 1999.
Perspectives in Pulping and Bleaching Processes at the Crossing of the Millennium Frontier
Authors: de Choudens C. , Lachenal D.
Published: May 2018

The manufacturers of pulps must answer to the following three necessary requirements:

• environment protection

• pulp quality

• production cost reduction

If up to the present time, the environmental constraints have been emphasized (e.g. dioxin in late 1980's) over the two other criteria, namely quality and cost, today the challenge for the next years will be to improve each of these factors without weakening the other two.

The purpose of this paper is to discuss the respective merits of the various pulp manufacturing processes with the criteria expressed above and to draw the research and development efforts to undertake in this situation. Some personal opinions will be given on the issues.
Accuracy of Water Quality Predictions with Loading Scenarios of Forest Industry Waste Waters
Authors: Huttula Timo , Peltonen Anu , Frisk Tom , Wirola Hannu , Krogerus Kirsti
Published: May 2018

The environmental effects of the Finnish industrial loadings are in practice decided by water courts as they give permits. In decision-making they use an inspection procedure. Since 1970s in Finland within this procedure one method of environmental evaluation has been the application of numerical water quality models. At the Kokemäenjoki watercourse water quality effects of the paper and pulp mills in Mänttä, Lielahti and Valkeakoski were studied with two or three dimensional water quality models. On the basis of these results the costs and benefits of different loading options were considered. Now, after more than a decade, the response of the lake waters to the nutrient and BOD loading can be seen in the water quality monitoring results. We used these observations and studied the accuracy and limitations of these early water quality models.
Operational Issues with Impulse Drying Sludge
Authors: Beckley John , Banerjee Sujit
Published: May 2018

Impulse drying technology can be applied to most primary and mixed primary/secondary cakes from pulp and paper operations. Results from the first two onsite trials illustrate some of the factors that govern dewatering including belt porosity, roll temperature, pressure, belt cleaning, ash content, sludge feed delivery, and sludge structure and type. Roll sticking is one of the most important factors that govern the application of the technology. The potential for roll sticking cannot presently be evaluated a priori. Refinements made in the unit as a result of these trials are discussed.
Management of Accidental Releases in the Forest Industry
Authors: Malmén Y. , Tiihonen J. , Wessberg N.
Published: May 2018

In this paper, a method for the management of accidental releases in the forest industry is introduced. The aim of this method is to reduce the environmental consequences of spills escalating through damage to the biological wastewater treatment plant. The method covers also accidental releases into the atmosphere to watercourses, and to the soil/groundwater. This paper describes how the method for the management of the potential accidental releases works, focusing especially on the identification procedure (HAZSCAN), and the experience obtained when applying the method in the three forest industry plants.
Ammonia removal from young landfill leachate by magnesium ammonium phosphate precipitation and air stripping
Authors: Kabdaslı I. , Tünay O. , Öztürk İ. , Yılmaz S. , Arıkan O.
Published: May 2018

Leachate from sanitary landfills is a strong wastewater in terms of organic matter and ammonia. Organic matter can be reduced by anaerobic plus aerobic treatment; however, ammonia reduction by nitrification often poses problems due to inhibition. In this study, ammonia removal by physical chemical treatment from young leachate and anaerobically treated young landfill leachate was experimentally investigated. Magnesium ammonium phosphate precipitation (MAP) and ammonia stripping at pH 12 provided ammonia removals over 90 and 85% respectively. Up to 80% COD removal was obtained with MAP precipitation of raw leachate.
Environmental engineering education in Japan
Authors: Mino T.
Published: May 2018

The curriculum in environmental engineering at undergraduate and graduate level at the University of Tokyo is described in detail as an example of environmental engineering education in Japan. The environmental engineering curricula of three major Japanese universities, namely, Hokkaido University, the University of Tokyo and Kyoto University, are compared. Future needs for environmental engineering education are discussed.
Anaerobic hydrolysis kinetics of particulate substrates
Authors: Sanders W.T.M. , Geerink M. , Zeeman G. , Lettinga G.
Published: May 2018

A mathematical description of the surface related hydrolysis kinetics for spherical particles in a batch digestion is presented as well as a verification of this model with particulate starch as a substrate. Three substrates containing starch with different particle size distributions (PSD) were used. Two were obtained from fresh potatoes by wet sieving and for the third substrate a commercially available starch was used. The substrates were batch digested at 30°C with granular sludge as inoculum and the hydrolysis efficiency was measured and fitted with the model. The results revealed that the hydrolysis rates for the three substrates were equal, viz. 0.4±0.1 g starch/m2/hour. Moreover, for the commercial starch not only the hydrolysis efficiency but also the changes within the PSD of the starch was determined several times with the use of light microscopy and image analysis. The obtained experimental PSD showed good similarity with the theoretical PSD from model calculations. This shows that thesurface of the particulate substrate is the key factor for the hydrolysis process.
Thermal hydrolysis (TDH) as a pretreatment method for the digestion of organic waste
Authors: Schieder D. , Schneider R. , Bischof F.
Published: May 2018

The recycling concept under consideration is based on the process of Thermal Hydrolysis (TDH) followed by an anaerobic digestion. By increasing pressure and temperature the organic part of the waste is split up in a first step into short-chain fragments that are biologically well suited for microorganisms. The following fermentation runs much faster and more complete than in conventional digestion processes and the biogas yield is increased. Left is just a small amount of a solid residue that can be easily dewatered and utilized as surrogate fuel for incineration or as compost additive. The thermal hydrolysis process allows a complete energy recovery from organic waste. During the total procedure more energy sources are produced than are needed for running the plant. The procedure is especially suited for wet organic waste and biosolids that are difficult to compost, such as food scraps, biological waste from compact residential areas and sewage sludge. As a complete disinfection is granted due to the process temperatures the procedure is also suited for carcasses.
Odour control and the planning arena
Authors: Manning K. S. , Jeavons J. A.
Published: May 2018

Odour pollution is traditionally categorised as a public health issue, controlledv, ia statutory legislation with the emphasis on control rather than prevention. As society demands a higher quality environment, odour pollution increases in importance as an amenity issue. Planning authorities can refuse planning permission on the grounds that the odour nuisance from the proposed development will be detrimental to the amenity of the area. Planningauthorities are therefore in the unique position of being able to prevent odour pollution. Potential odour polluters are under increasing pressure to demonstrate to planning authorities that odour has been minimised as far as possible. The communication of technical odour control data and assessments, through mechanisms such as Environmental Impact Assessments (EIA), is becoming an important part of the decision making process. The lack of specific odour policy and guidance within the planning arena is highlighted. The reconstruction of Derby Sewage Treatment works (STW) is used a a case study to highlight how a technical assessment of odour emissions, using the WRc Sewage Treatment Odour Production (STOP) Model can be successfully used within the planning arena to achieve planning permission with no additional conditions.
Odour emission estimates and control strategies using models and sampling for East Bay Municipal Utility District's collection sewage system and wastewater treatment plant
Authors: Witherspoon J. R. , Sidhu A. , Castleberry J. , Coleman L. , Reynolds K. , Card T. , Daigger G. T.
Published: May 2018

For several years, public complaints regarding odours generated by East Bay Municipal Utility District's (EBMUD's) wastewater treatment plant and sewage collection system (SCS) have been increasing. In response, an Odor Control Master Plan was completed to develop near- and long-term odour abatement strategies for their wastewater system. The plan's strategies include using an advisory committee to assist in setting odour threshold levels, prioritizingodour sources, issuing an odour-status newsletter, and reviewing odour control options. The objective is to provide an odour-free community environment at least 99 percent of the year.

This paper provides innovative approaches to estimate odour emissions and identify viable odour control options for SCSs through complete wastewater treatment. This paper also presents a CH2M HILL SCS odour model comparison to a comprehensive EBMUD sewage system corrosion study, illustrating that areas having high predicted odours also have high corrosion rates.
Northumbrian Water coastal programme: nine scrubbers for the price of eight!
Authors: Lloyd T. C.
Published: May 2018

Under the EU Urban Wastewater Treatment Directive, Northumbrian Water have to provide full sewage treatment at eight coastal sites for 1999/2000 deadlines. As part of the consequent standardisation programme, NWL appointed Entec to co-ordinate odour containment, ventilation and abatement at all eight sites. Following trials and a review of options, NWL specified the ICI “Odorgard” catalytic single stage scrubber as the standard abatement method.

Tenders were sought using ECC Option A (activity schedules) conditions of contract from the three licensees. Costs were identified for anticipated odour loads/installation programmes to maximise “bulk discount” opportunities, culminating in simultaneous contracts being let to ERG for all eight sites. This represents the largest known multi-site odour abatement award in the water industry to date effectively giving discounts equivalent to the cost of the ninth scrubber.

Further advantages of the bulk purchase included common operational procedures/spares and the ability to apply lessons being learnt from commissioning of prior scrubber installations.
The ability of selected chemicals for suppressing odour development in rising mains
Authors: Hobson J. , Yang G.
Published: May 2018

The use of Nutriox® and ferric chloride to suppress hydrogen sulphide and odour generation in rising mains is evaluatd in a pilot scale study. Without chemical dosing the hydrogen sulphide built up to the commonly predicted levels after six months. Thereafter, addition of both Nutriox® and ferric chloride to sewage entering the rising main totally suppressed the formation of H2S. Nutriox also nearly totally suppressed the odour measured olfactometrically. The use of ferric salt at near stoichiometric levels effectively removed dissolved sulphide. Odour removal was generally good though on occasions reduction of dissolved sulphide levels to below 0.1 mg/l was not guaranteed to be accompanied by near total suppression of odour generation. The use of ferric ions at stoichiometric levels, after H2S and odours have formed in the rising main, also eliminated the dissolved sulphide. When used in this way, a significant residual odour potential, 110,000 ou/m3 remained in the sewage. The simultaneous reductions of odour and hydrogen sulphide observed in this study implied an apparent threshold odour concentration of 0.1 ppb for H2S, significantly lowr than most values quoted in the literature.
The effect of preozonation on microorganism and particle removal
Authors: Gaubert J. Y. , Piet C. , Gatel D. , Bonne P. , Hutchison J. , Cavard J.
Published: May 2018

The new European regulation on treated water focuses on oxidation by-products and consequently the use of ozone for parasites and virus inactivation should be limited. To achieve the necessary removal of parasites by a multi-barrier water treatment plant, physical removal needs to achieve consistently high levels of particle and microorganism removal. TheNeuilly-sur-Marne treatment plant treats raw water of particularly poor bacteriological quality. In order to improve the filtered water quality, preozonationhas been tested in a pilot scale study. Results obtained have confirmed that, with this sort of raw water, preozonation directly on the raw water or on the settled water can provide a significant improvement in filtered water. This is true for both particles and coliforms. It appears that an ozone dose of 0.5 g/m3 is enough to achieve a constant level of efficiency.
Performance testing and operational experience of a Fibrotex plant installed to treat a 40 Ml/d groundwater source
Authors: Hutchison J. , Horner D. , Pearce G.
Published: May 2018

Clay Lane Water Treatment Works, owned and operated by Three Valleys Water (part of the Vivendi Group), is located in Watford in the South East of England. The raw water supplying the works is taken from eight chalk borehole sources in the surrounding area and treatment at Clay Lane consists of ozonation, rapid gravity filtration (GAC media) and disinfection with sodium hypochlorite. Ozone and GAC are used primarily for pesticide removal. In 1997 a decision was taken to install additional treatment at one of the sources, Eastbury, which can supply up to 40 Ml/d to Clay Lane and which has on occasions been subject to surface water influence and poor quality following heavy rainfall. Given the potential risk from contamination by Cryptosporidium oocysts, a Fibrotex plant capable of achieving 99% (2 log) removal of oocysts was selected as the appropriate treatment. This paper reviews the results obtained during the performance testing, both on site during commissioning and subsequently during the Cryptosporidium oocyst challenge test. In addition, the operation of the plant over the last 18 months is reviewed.
Examination of Giardia and Cryptosporidium in water samples and fecal specimens in Taiwan
Authors: Hsu B-M. , Huang C. , Hsu Y-F. , Hsu C-L.L.
Published: May 2018

Giardia and Cryptosporidium have emerged as waterborne pathogens of concern over the past few decades. Twenty-nine source water samples were collected from water treatment facilities and checked for the occurrence of Giardia and Cryptosporidium along with some water quality parameters. These facilities include ten large-scale treatment plants near major metropolitan areas, and eight simple facilities in small and secluded communities. The indirect immunofluorescence assay (IFA) was used for the detection of cysts and oocysts in water samples. In addition, fecal specimens were collected from watersheds providing source water for the treatment plants, and the presence of Giardia and Cryptosporidium was detected with the enzyme-linked immunosorbent assay (EIA). The mean concentrations of protozoa in large-scale plants were 66.6 cysts/100 litres and 89.2 oocysts/100 litres, whilesimple facilities contained 1.27 cysts/100 litres and 0.28 oocysts/100 litres, respectively. The concentrations of these two parasites exhibit the highest correlation with turbidity than any other water quality parameters. Amongthe 101 fecal specimens, eleven were positive for Giardia and 22 were positive for Cryptosporidium. It was also found that the occurrence of these two pathogens in the source water was directly linked to the surrounding farming activities, suggesting that farming activities should be kept at a certain distance from the watersheds.
Operation of modern day process plants – minimising Cryptosporidium risk
Authors: Edwards D.
Published: May 2018

Closer examination of basic water treatment processes, “source to tap”, is one of the evident supplier responses to new quality constraints and increasing resource pressures.

More recently, with the release of DWI Incident Reports and UKWIR documentation on the organism Cryptosporidium, the focus has been extended to defining and operating at “optimal” conditions within treatment processes.

As a result the Water Industry is currently re-evaluating “due diligence” guidance of operational procedural practices on treatment streams, in order to consistently produce potable water to an ever increasing standard, and thus lowering the public health risk.
Development of a mathematical model of Cryptosporidium inactivation by ozonation
Authors: Somiya I. , Fujii S. , Kishimoto N. , Kim R-H.
Published: May 2018

A new mathematical model was developed to express the processes of Cryptosporidium inactivation by ozonation. In this model, five different stages were considered as state variables of Cryptosporidium oocysts for accurate expression of the inactivation. ATP, in vitro excystation and DAPI/PI permeability assays were used to describe the oocyst amounts of different stages. Some reaction constants were estimated by the structure components of oocysts or by the stoichiometry of reactions, while the others were by the oocysts population changes in ozonation. The calculated values of this model were well consistent with experimental inactivation data. Three-log inactivation of sporozoites required about 0.04 mgO3 per unit oocyst (mgC) from the simulation results. Before ozone reacts with sporozoites, more ozone was consumed to oxidize other parts of oocysts and DOC produced. The main path of inactivation of oocysts by ozonation was estimated to be P1 (intact oocysts)→P2 (oocysts with damaged outer oocyst wall)→P4 (oocysts without excystation function)→P5 (oocysts with inactivated sporozoites and no excystation function) from experimental and simulated results.
Evaluation of full scale thermal solidification processes implemented in Tokyo lightweight aggregate, slag and brick
Authors: Okuna N. , Yamada A.
Published: May 2018

Tokyo has an experience in operation of full-scale thermal solidification processes for around 10 years. They include artificial lightweight aggregates, slag, brick, and sludge fuel (dried by Carver Greenfield process). Many efforts were concentrated on improving the processes for the years. As a result, the thermal solidification of sewage sludge is no more academic research subject, but is a standardized engineering process. Anyof them are able to be locally implemented depending on specific requests. Among them, the brick seems to be the best choice from the viewpoint of economy. On the other hand, a potential alternative is that the sewage sludge could be served as raw material for Portland cement manufacturing process.
The feasibility of electro-osmotic belt filter dewatering technology at pilot scale
Authors: Snyman H. G. , Forssman P. , Kafaar A. , Smollen M.
Published: May 2018

Sewage sludge is typically dewatered using drying beds, belt filter presses or centrifuges. Mechanical dewatering of sludge is costly in terms of capital and running costs, especially the flocculent. In an attempt to address the need for more cost-effective dewatering technologies, electro-osmotic belt filtering was developed by Smollen and Kafaar in 1995. Themechanical equipment resembles a belt filter press but the belts are stainless steel, woven belts, which act as the electrodes. In this study, thefeasibility of the technology was tested at pilot scale using wasteactivated-, anaerobically digested- and dissolved air flotation sludge. The parameters which were investigated includes the applied voltage, polyelectrolyteusage and sludge feed rate. Applied voltage of between 15 and 25 volts increased the dewatering significantly in the waste activated- and anaerobically digested sludge. Applying a voltage in dissolved air flotation sludge could not enhance the efficiency of dewatering, unless stored to de-air. The technology was found as sensitive to polyelectrolyte dosages as belt presses. The performance of the electro-osmotic belt filter was sensitive to feed rate, but performed well with non-thickened waste activated sludge (0.61% solids), resulting in cake solids above 20%.
Provision of sewage and sludge treatment for Athens
Authors: Thomas V.K. , Adraktas D.V. , Taylor C.
Published: May 2018

Phase A of the Psyttalia WwTP, providing preliminary and primary treatment for the wastewater of the 3.3 million inhabitants and the industries of the Athens greater area was commissioned in mid 1994. Treated effluent is discharged at 65 m depth in the Saronikos Gulf, via a long twin outfall. A new EUR 140 million contract was signed in December 1998 for the expansion of the treatment plant (Phase B), to include biological treatment (carbon removal, nitrification, partial denitrification) of the wastewater as well as treatment of the sludge produced (thickening, anaerobic digestion, dewatering). Effluent quality shall conform with the EU urban wastewater treatment Directive (91/271/EEC). It is expected that the new Phase B works shall be commissioned in early 2002. Several options for the utilisation and disposal of the produced sludge are currently evaluated, including thermal drying and use in cement factories and power plants, co-composting with municipal refuse, etc.
The two phase anaerobic digestion process: sludge stabilization and pathogens reduction
Authors: Huyard A. , Ferran B. , Audic J.-M.
Published: May 2018

Regulations for land application of wastewater sludges require the performing of treatment with a high efficiency on pathogens reduction. a reduction of 61% of the Volatile Solids content of the sludge, a reduction of fecal coliform, polio virus and Ascaris egg of 5.5, 4.0 and 2.6 respectively are achieved with a thermmophilic/mesophilic Two Phase Anaerobic Digestion process. According to the EPA 40 CFR 503 regulation, the process produces Class A biosolids and could be recommended as a Process to Further Reduce Pathogens.
Thermophilic anaerobic digestion and pasteurisation. Practical experience from Danish wastewater treatment plants
Authors: Nielsen B. , Petersen G.
Published: May 2018

Increasing sludge disposal costs have highly intensified the interest in reducing the sludge quantities from Danish wastewater treatment plants. By upgrading existing mesophilic digesters to the thermophilic temperature range, the retention time can be halved and many digesters designed only for primary sludge will have sufficient capacity to treat also the biological excess sludge.

At the moment, eight full-scale thermophilic digesters are in operation in Denmark and five are under construction. This paper describes the full-scale experience gained from digestion of biological excess sludge as well as a mixture of primary and biological sludge.

Thermophilic digestion has proven to be a good and stable process for solids reduction and pathogen removal. The digested sludge can be dewatered to a high solids content and thereby the sludge quantity for disposal can be reduced by 30-40% depending on the type of wastewater treatment plant. A drawback of the process is that the polymer costs for sludge dewatering may be increased depending on the sludge type.
Storm operation strategy: high-flow activated sludge process operation
Authors: Carrette R. , Bixio D. , Thoeye C. , Ockier P.
Published: May 2018

Current practice in Flanders (Belgium) is to limit the hydraulic capacity of the waste water treatment plant to 6Q14. A maximum of 3Q14 is treated in the activated sludge system, the excess flow undergoes only physical treatment (stepscreen, sand trap and settling). This paper focuses on an alternative storm management operation strategy aiming at maintaining plant performance and reducing the total pollutant discharge towards the receiving waterbody. Given the observed dilution of incoming waste water under storm conditions, the idea was put forward that higher hydraulic loadings could be treated within the biology if additional secondary clarifier volume was supplied. The new storm operation strategy would consist of treating 6Q14 biologically using the available storm tanks as additional clarifier volume. Dynamic simulation was used to asses the feasibility of this strategy. In a next step a full scale test was run over several months. The outcome of this case study clearly shows that 6Q14 can be treated biologically using the storm tank as anextra clarifier.This operation mode eliminates the direct overflow of only physically pre-treated waste water coming from the stormtank towards the receiving waterbody. It was shown that doing so the overall pollutant discharge was significantly reduced.
Improving secondary clarifier performance and capacity using a structured diagnostic approach
Authors: Parker D.S. , Wahlberg E.J. , Gerges H.Z.
Published: May 2018

The causes of high effluent suspended solids (ESS) from secondary clarifiers are often incorrectly identified resulting in improperly focused remedial actions that do not yield the desired results. In this paper we demonstrate a structured diagnostic approach that allows relatively rapid problem isolation and resolution. A sequence of tests, procedures or observations are described that allow problems to be classified into one or more of the following categories: (1) denitrification or rising sludge, (2) high sludge blankets, (3) flocculation or breakup problems, and (4) hydraulic problems. The following tools are used in the approach: (1) direct observation, (2) blanket detection, (3) measurement of sludge thickening properties, (4) solids flux or state point analysis, (5) dispersed suspended solids (DSS) test, (6) flocculated suspended solids (FSS) test, (7) dye testing, and (8) hydrodynamic modeling. The structured diagnostic approach has been applied and refined by the authors over nearly three decades and has proven extremely useful in rapidly identifying the least-cost technology for reducing ESS. Case examples are presented where the structured diagnostic approach is used to isolate the problems and identify the most appropriate remedy.
Changes of toxicological properties of biodegradation products of anthracene and phenanthrene
Authors: Traczewska T. M.
Published: May 2018

The aim of this work was to determine toxicity and mutagenicity of anthracene and phenanthrene and their microbial biotransformation products. The following representatives of different trophic levels of aquatic biocenoses were selected for the toxicological tests: Selenastrum capricornutum, Lemna minor, Daphnia magna and Lebistes reticulatus. Mutagenic properties were determined by Ames test. Results of the analyses confirmed toxicity of studied PAHs for test organisms. Metabolites produced during biological degradation of anthracene and phenanthrene were also harmful for selected representatives of aquatic ecosystems.
Linking microbial community structure to pollution: Biolog-substrate utilization in and near a landfill leachate plume
Authors: Rüling W. F. , van Breukelen B. M. , Braster M. , van Verseveld H. W.
Published: May 2018

Previously, we observed that microbial community structure and functional diversity in aquifers might be enhanced by landfill leachate infiltration. To study this hypothesis, groundwater samples were taken near the Banisveld landfill, The Netherlands. Based on hydrochemical parameters, the samples clustered into two groups. One group corresponded to polluted samples from the plume of landfill leachate and the second group to clean samples from outside the plume. Most Probable Number-Biolog was used to select Eco Biolog plates with similar inoculum densities. Analysis of substrate utilization profiles of these plates revealed that anaerobic microbial communities in polluted samples clustered separately from those in clean samples. Especially substrates containing an aromatic nucleus were more utilized by microbial communities in the leachate plume. Both substrate richness and functional diversity were significantly enhanced in the plume of pollution. This study shows that community-level physiological profiling is a useful and simple tool to distinguish between anaerobic microbial communities in and near a landfill leachate plume.
Development and application of a denitrification test based on gas production
Authors: Buys B. R. , Mosquera-Corral A. , Sánchez M. , Méndez R.
Published: May 2018

In order to assess the toxicity of compounds in wastewater and activities in reactors a precise, reproducible, fast and simple batch test is used. This research was focused on the development of such a test to determine denitrifying activity. The test is based on measuring the rate of gas production during denitrification, by tracking both the pressure and the gas composition in the headspace of a sealed bottle. The optimum pH for batch activity was found to equal the pH in the lab-scale reactor (9.5) from which the sludge originated. The minimum COD/N ratio required for linear gas production curves with acetate/nitrate was 3.5 g COD/g N. A significant increase in specific activity at low solids concentrations (<2 g VSS/l) was observed. No clear relation between activity, DNA and RNA content of the sludge after the test and initial substrate to biomass (S0/X0) ratio could be established, indicating that other factors play a role in determining the activity, possibly adsorption and substrate mass transfer. Standardization of batch tests should therefore include the solids concentration.
Activated carbon as a better habitat for water and wastewater treatment microorganisms
Authors: Okada M. , Morinaga H. , Nishijima W.
Published: May 2018

Effects of PAC on bacterial activity were evaluated by sequencing batch cultures (20 hours each) of E.coli K-12 on synthetic medium containing glucose as a sole carbon source. Four suspended sequencing batch culture systems were operated; CP: cultures supplemented with PAC, CR: cultures with removal of metabolites by PAC at the end of each batch culture, CD: cultures supplemented with PAC in dialysis tubing to separate from E.coli, and CC: cultures without PAC (control). The supernatant of each batch culture was filtered through a membrane filter (0.2 μm) and was mixed with the same volume of fresh medium to be used as the medium for the next batch culture. The sequencing batch cultures were repeated three times for all the systems. The bacterial growth in CC was inhibited with the increase in the number of batch cultures. Although a significant amount of metabolites was accumulated in the 3rd batch culture of CC, little accumulation was noted in the 3rd batch culture of CP. No growth inhibition was noted in CP for all the batch cultures. The little differences in the bacterial yield and metabolite accumulation between CR and CD suggested that adsorption/desorption of metabolites with PAC did not play a major role in bacterial growth. PAC addition may partly stimulate the growth by the removal of growth inhibiting metabolites. However, the fact that CP showed higher yield than CR and CD indicated that the contact between bacteria and PAC plays a significant role in the growth of bacteria.
Impact of advanced oxidation processes on the biodegradation kinetics of industrial wastewater
Authors: Ledakowicz S. , Solecka M.
Published: May 2018

Advanced oxidation processes (AOPs) were applied prior to biological aerobic treatment by means of activated sludge. Textile wastewater was chosen as an example of industrial wastewater and the chemical oxygen demand – COD – was an overall measure of biodegradable substrate concentration, while the biomass concentration was expressed by volatile suspended solids – VSS. The kinetic investigations were applied to synthetic wastewater consisting of anthraquinone dyestuff Acid Blue 40 C.I., anionic detergent Avivage KG conc., softening agent Tetrapol CLB and mineral salts. Kinetics of microbiological destruction of the pollutants were described by the Monod equation. The kinetic parameters of the equation: maximum specific rate of microbial degradation, affinity (Monod) constant and yield coefficient were identified from the experimental data obtained at laboratory scale. The influence of various AOPs on the kinetics of biodegradation was analysed. The experimental evidence of the positive effect of chemical oxidation pretreatment on the biodegradation of recalcitrant compounds was quantified by estimation of the kinetic parameters of the Monod equation employed in biodegradation of the wastewater.
Biofiltration of volatile organic compounds – application to air treatment
Authors: Ramirez-Lopez E. M. , Montillet A. , Comiti J. , Le Cloirec P.
Published: May 2018

A hydrodynamic study and an ethanol biodegradation were carried out in an experimental biofilter using wood bark as packing material. The Comiti and Renaud model was used in order to determine, from pressure drop measurements, the tortuosity and the dynamic specific surface area of the packing material, and its structural parameters, considering the wall effect corrections. The pressure drop was used as a qualitative measure of the growth of native wood bark microorganisms. The aerobic biodegradation with a concentration of 1 g of ethanol m–3 was studied. An air superficial velocity of 100 m h–1, an air flow rate of 20 m3 h–1 and an empty bed residence time of 37 seconds with a true residence time of 19.5 s were the operational conditions in the biofilter. The ethanol concentration, pH, temperature and the pressure drop at different heights of the biofilter were measured. Performances of this process were presented.
Effects of Fe2+ on sludge granulation in upflow anaerobic sludge blanket reactors
Authors: Yu H. Q. , Fang H. H. P. , Tay J. H.
Published: May 2018

Experiments were performed in parallel using six identical UASB (upflow anaerobic sludge blanket) reactors to examine the effects of iron (Fe2+) on sludge granulation during start-up. Introduction of Fe2+ at concentrations of 300 and 450 mg/L enhanced the granulation process in UASB reactors, while dosage of Fe2+ (150 mg/L) had little effect on the sludge granulation. The Fe2+concentration in granules was nearly proportional to the influent Fe2+concentration. The specific activity of granules decreased with increasing Fe2+/concentration in the feed. For high Fe2+ dosages, a large amount of minerals was deposited within the granules, and FeS and the compounds formed by iron and exopolysaccharide polymers were the main precipitates. This, along with the significant decrease in the water content in granules and the possible toxicity of high-level Fe2+accumulated inside granules, reduced bacterial specific activity.
Nutrient balancing for enhanced activated sludge reactor performance: UK perspective
Authors: Burgess J. E. , Harkness J. , Longhurst P. J. , Stephenson T.
Published: May 2018

Trace metals (K, Fe, Mg, Cu, Ca, Mn, Al, Zn, Mo, Co) and vitamins (biotin, niacin, pyridoxine, lactoflavin, thiamine, pantothenic acid) were tested for enhancing chemical oxygen demand (COD) and toxicity removal in activated sludge treating trade effluent. Rapid respirometry screening indicated that micronutrient addition could not ameliorate macronutrient deficiencies, but could significantly improve the degradation of hard COD in the wastewater (up to 4.24 kg COD/kg MLSS/d, i.e. 320% of the control) with no significant effect on the air requirement of the sludge. Several positive effects led to the conclusion that micronutrients have the potential to optimise the process performance of activated sludge plants treating industrial wastewater. Porous pots were used to further trial eight of the micronutrients. The retention of biomass in the pots was increased in all cases. Improvements in the degradation of COD (up to 260% of the control) were observed while biological oxygen demand (BOD) degradation was not affected. This implied the use of recalcitrant substrate components as a food source. Toxicity tests showed that the effluents from the experimental porous pots were less toxic than the control effluents. The effects of niacin addition in activated sludge treatment of industrial waste at pilot-scale were: improved sludge handling, increased COD, ammonia, suspended solids and phosphorus removal. Several industrialists saw micronutrient addition as a route to successful adaptation of processes to accommodate toxicity– based legislation.