bluuebunny/crossref_metadata_2025 huggingface dataset:
Calibration and simulation of two large wastewater treatment plants operated for nutrient removal
Authors: Ferrer J. , Morenilla J.J. , Bouzas A. , Garcia-Usach F.
Published: May 2018

Control and optimisation of plant processes has become a priority for WWTP managers. The calibration and verification of a mathematical model provides an important tool for the investigation of advanced control strategies that may assist in the design or optimization of WWTPs. This paper describes the calibration of the ASM2d model for two full scale biological nitrogen and phosphorus removal plants in order to characterize the biological process and to upgrade the plants' performance. Results from simulation showed a good correspondence with experimental data demonstrating that the model and the calibrated parameters were able to predict the behaviour of both WWTPs. Once the calibration and simulation process was finished, a study for each WWTP was done with the aim of improving its performance. Modifications focused on reactor configuration and operation strategies were proposed.
Enhanced aerobic floc-like granulation and nitrogen removal in a sequencing batch reactor by selection of settling velocity
Authors: Kim S.M. , Kim S.H. , Choi H.C. , Kim I.S.
Published: May 2018

In order to enhance the solidÐliquid separation properties and nitrogen removal efficiency of SBR, the aerobic floc-like granules were cultivated under temporal alternating aerobic and anoxic conditions without the presence of carrier material in a SBR having 15 H/D (height/diameter) ratio. Two different effluent port positions were applied to the SBR for different selection of minimum settling velocities (over 0.6 and 0.7 m/h) of granules retained in the SBR during aerobic floc-like granule formation. The effect of different minimum settling velocities as an operational parameter on the size and solidÐliquid separation properties of floc-like granules and also the COD and nitrogen removal of SBR were evaluated. The reactor was operated 6 hours per cycle (aerobic 4.75 hours, anoxic 1.25 hours) under chemical oxygen demand (COD) loading rate of 2.5 kg/m3·d (1.3 kg acetate-COD and 1.2 kg glucose-COD). When increasing the minimum settling velocity by 0.1 m/h, the following results were observed at steady state. The nitrification efficiency was not changed at about 97% but the denitrification efficiency was improved from 78 to 97%. The COD removal efficiency was improved from 82 to 97% and the concentration of biomass in the reactor was retained at lower level at about 3,000 mg MLSS/L. The average sludge volume index (SVI) value of granules was decreased about 85 to 50 mL/g and the granule sizes were increased 0.1-0.5 mm to 1.0-2.0 mm. The required time to form granules and reach steady state was significantly shortened. Based on the results, the selection of the minimum settling velocity had a significant effect on both the physical properties of granules and the SBR performance, so it is suggested to use the minimum settling velocity as an operational parameter.
Model-based evaluation of nitrogen removal in a tannery wastewater treatment plant
Authors: Moussa M.S. , Rojas A.R. , Hooijmans C.M. , Gijzen H.J. , van Loosdrecht M.C.M.
Published: May 2018

Computer modelling has been used in the last 15 years as a powerful tool for understanding the behaviour of activated sludge wastewater treatment systems. However, computer models are mainly applied for domestic wastewater treatment plants (WWTPs). Application of these types of models to industrial wastewater treatment plants requires a different model structure and an accurate estimation of the kinetics and stoichiometry of the model parameters, which may be different from the ones used for domestic wastewater. Most of these parameters are strongly dependent on the wastewater composition. In this study a modified version of the activated sludge model No. 1 (ASM 1) was used to describe a tannery WWTP. Several biological tests and complementary physical-chemical analyses were performed to characterise the wastewater and sludge composition in the context of activated sludge modelling. The proposed model was calibrated under steady-state conditions and validated under dynamic flow conditions. The model was successfully used to obtain insight into the existing plant performance, possible extension and options for process optimisation. The model illustrated the potential capacity of the plant to achieve full denitrification and to handle a higher hydraulic load. Moreover, the use of a mathematical model as an effective tool in decision making was demonstrated.
Organic and detergent degradation in combined O3/UF for domestic laundry wastewater reclamation
Authors: Seo G.T. , Lee T.S. , Kim J.T. , Yoon C.H. , Park H.G. , Hong S.C.
Published: May 2018

This paper focuses on the evaluation of organic and detergent degradation in a combined Ozone/UF system for domestic laundry wastewater reclamation. Formation of by-product was investigated by GC/MS for the reclaimed water. Ozone was injected into the raw wastewater in a 10 L contact tank and the wastewater was circulated through the membrane module for inner pressurized cross-flow filtration. The concentrate was returned back to the contact tank. The membrane used in this experiment was hollow fiber polysulfone UF membrane with MWCO 10,000. It has an effective filtration area of 0.06 m2. The experiment was carried out with intermittent ozone injection, 5 min injection and 10 min idling. Ozone was dosed at the concentration of 1.5 mg/L. The flux of the UF could be maintained at 0.24 m/d under filtration pressure 40-45 kPa and water temperature, 20-22°C. The organic removal efficiency by the system was 90% in terms of COD. Ozone was considerably effective to degrade organics in the wastewater. Molecular weight of organics in the raw waste was mostly greater than 10,000 (72% of 950 mgCOD/L). However 86% of effluent COD (94-100 mg/L) was composed of organics smaller than MWCO 500 by ozone injection. No harmful by-products by ozone contact were detected from the analysis of treated water using GC/MS. It was identified that residual organics in the treated water were 1,1′-Oxybisbenzene, Octadecanoic acid, Squalene and Benzenmethanol, etc., which were additives contained originally in the detergent. Consequently the reclaimed water quality could be estimated safe enough to recycle for the rinsing cycle in a washing machine.
Re-use of wastewater: preventing the recovery of pathogens by using medium-pressure UV lamp technology
Authors: Kalisvaart B.F.
Published: May 2018

Ultraviolet (UV) light has become widely accepted as an alternative to chlorination or ozonation for wastewater disinfection. There are now over 2,000 wastewater treatment plants worldwide using either low- or medium-pressure UV technology. Recent studies investigating UV lamp technology, configuration, cleaning requirements and ageing, as well as long-term performance tests, have demonstrated beyond any doubt the effectiveness of UV in inactivating pathogens in wastewater. Research has also shown that, to ensure permanent inactivation and prevent the recovery of microorganisms following exposure to UV, a broad, “polychromatic” spectrum of UV wavelengths is necessary. These wavelengths inflict irreparable damage not only on cellular DNA, but on other molecules, such as enzymes, as well. Only medium-pressure UV lamps produce the necessary broad range of wavelengths; low-pressure lamps emit a single wavelength peak which only affects DNA. Polychromatic medium-pressure UV light is so effective because of the lampÕs exceptionally high UV energy output at specific wavelengths across the UV spectrum. It has been shown, for example, that pathogenic E. coli O175:H7 was able to repair the damage caused by low-pressure UV, but no repair was detected following exposure to UV from medium-pressure lamps.
Upgrading and expansion of the Käppala wastewater treatment plant. Operational experiences and results
Authors: Manhem P. , Palmgren T.
Published: May 2018

Käppala Association has the responsibility to receive and treat wastewater from 11 municipalities situated just north of Stockholm in Sweden. Running a tunnel system, 60 km long, and a treatment plant meets this responsibility. The plant is situated in Lidingö, northeast of Stockholm. The load 2002 corresponds to about 520,000 p.e.

During the 1990s the plant was upgraded and expanded to meet an increasing population and more stringent discharge limits. Nitrogen removal was introduced. The expansion was done in two steps; the first step comprised a new plant beside the old one both situated in rock. This part, which included the filtration step, was taken into operation in 1998. Then the old plant was upgraded to the same technical standard as the new part. His Majesty the King of Sweden inaugurated the whole new and upgraded plant in April 2000. A total of 1.3 billion Swedish crowns were invested corresponding to about 140 million euro.

The plant's performance is good. There is no trouble keeping the discharge limits, 10 mg/l for BOD7 and total nitrogen and 0.3 mg/l for phosphorus. However the bio-P process has not been altogether successful. We haven't been able to fulfill our goal to reduce the use of iron sulphate. We will during 2003 go on in our investigations concerning running the plant with a combination of bio-P and chemical precipitation.
Denitrification rate and carbon source consumption in ull-scale wastewater filtration
Authors: Jonsson L.
Published: May 2018

In response to new demands for increased removal of nitrogen and phosphorus, the Henriksdal and Bromma treatment plants, with hydraulic loads of 283,000 and 148,000 m3/d, respectively, built filtration steps as a final process step in the plants. The denitrification rates in a full-scale and in a pilot plant filter are calculated to 13.1 and 21.3 g (NO3+NO2)-N/(m3·h), respectively, in the total filter bed after 2.5-24.2 and 16.0-28.0 h of operational time, and 6.4 and 18.7 g (NO3+NO2)-N/(m3·h), respectively, after 1.0 and 0.1-0.9 h of operational time. In composite samples, the denitrification rate in the total filter bed is 10-20 g (NO3+NO2)-N/(m3·h) in the full-scale filter. The average values for k = ΔCODf/ΔCT are 1.6 and around 3 in the total filter bed in steady state and in the beginning of the experiments, respectively, both in the full-scale and in the pilot plant study. The carbon source costs for reducing the concentration of nitrate nitrogen in the Bromma plant from 12 to 8 mg/l in the effluent are 117,400 EUR and 147,400 EUR with methanol and ethanol, respectively, as a carbon source.
A guideline for simulation studies of wastewater treatment plants
Authors: Langergraber G. , Rieger L. , Winkler S. , Alex J. , Wiese J. , Owerdieck C. , Ahnert M. , Simon J. , Maurer M.
Published: May 2018

A guideline for simulation studies of wastewater treatment plants is proposed. The aim of the HSG-guideline is to define a reference quality level that helps to make the results of simulation studies comprehensible and comparable and therefore increases the quality and reliability of mathematical modelling in wastewater treatment. The paper gives a summary of the HSG-guideline, written by a group of university members from Germany, Austria and Switzerland.
Selection of an ultraviolet disinfection system for a municipal wastewater treatment plant
Authors: Kang S.J. , Allbaugh T.A. , Reynhout J.W. , Erickson T.L. , Olmstead K.P. , Thomas L. , Thomas P.
Published: May 2018

As part of an expansion to an average flow of 45.9 million gallons per day (174 mld), the Ypsilanti Community Utilities Authority wastewater treatment plant in the State of Michigan, USA, elected to install ultraviolet disinfection as a replacement for the existing chlorination process. This paper presents a unique methodology used in selecting the best system based on not only the life cycle costs, and O & M considerations but also the participation of the stakeholders. The Team members consisted of representatives of all departments at the Authority, and these Team members made the decision. The Team evaluated all criteria in the office, which was followed by verification at selected sites with similar types of equipment. The selected equipment then was pilot tested for validation of the dose-kill relationship under normal operation and also under reduced irradiation conditions. A low-pressure, high intensity system was selected, based on life-cycle cost, reliability, safety, and ease of operation. This paper describes the unique methodologies used in making that decision. The full-scale system is scheduled for start-up in Spring 2003.
Lamella separators in the upgrading of a large urban sewage treatment plant
Authors: Kolisch G. , Schirmer G.
Published: May 2018

Wupperverband is using lamella separators for the upgrading of its Kohlfurth sewage treatment plant that is currently in progress. The lamellae positioned at the outlet of the biological treatment stage already remove part of the biomass in the activation basin and prevent it from reaching the final clarification stage. This preliminary separation system reduces solids concentration in the biological treatment system without negative impact on final clarification and therefore also lowers the basin capacity needed, with positive effects on costs. This article gives an overview of the separation performance achieved.
Benchmarking of municipal waste water treatment plants (an Austrian project)
Authors: Lindtner S. , Kroiss H. , Nowak O.
Published: May 2018

An Austrian research project focused on the development of process indicators for treatment plants with different process and operation modes. The whole treatment scheme was subdivided into four processes, i.e. mechanical pretreatment (Process 1), mechanical-biological waste water treatment (Process 2), sludge thickening and stabilisation (Process 3) and further sludge treatment and disposal (Process 4). In order to get comparable process indicators it was necessary to subdivide the sample of 76 individual treatment plants all over Austria into five groups according to their mean organic load (COD) in the influent. The specific total yearly costs, the yearly operating costs and the yearly capital costs of the four processes have been related to the yearly average of the measured organic load expressed in COD (110 g COD/pe/d). The specific investment costs for the whole treatment plant and for Process 2 have been related to a calculated standard design capacity of the mechanical-biological part of the treatment plant expressed in COD. The capital costs of processes 1, 3 and 4 have been related to the design capacity of the treatment plant. For each group (related to the size of the plant) a benchmark band has been defined for the total yearly costs, the total yearly operational costs and the total yearly capital costs. For the operational costs of the Processes 1 to 4 one benchmark (€ per pe/year) has been defined for each group. In addition a theoretical cost reduction potential has been calculated. The cost efficiency in regard to water protection and some special sub-processes such as aeration and sludge dewatering has been analysed.
The HOCS paradigm shift from disciplinary knowledge (LOCS) - to interdisciplinary evaluative, system thinking (HOCS): what should it take in science-technology-environment-society oriented courses, curricula and assessment?
Authors: Zoller U. , Scholz R.W.
Published: May 2018

Given the current world state of affairs, striving for sustainability and the consequent paradigm shift: growth-to-sustainable development, correction-to-prevention and options selection-to-options generation: the corresponding paradigm shift in science-technology-environment-society (STES) education is unavoidable. Accordingly, the essence of the current reform in STES education, worldwide, is a purposed effort to develop students' higher-order cognitive skills (HOCS) capability; i.e., question-asking, critical system thinking, decision making and problem solving, at the expense of the “delivery” of lower-order cognitive skills (LOCS)-oriented knowledge. This means a paradigm shift from the contemporary prevalent LOCS algorithmic teaching to HOCS evaluative learning and HOCS-promoting courses, curricula, teaching strategies and assessment methodologies, leading, hopefully to evaluative thinking and transfer. Following the formulation of selected relevant axioms, major paradigm shift in STES research and education for sustainability have been identified. The consequent shift, in the STES context, from disciplinary to inter- and transdisciplinary learning, in science technology and environmental engineering education is discussed, followed by selected examples of successfully implemented HOCS-promoting courses, and assessment methodologies. It is argued, that transferable “HOCS learning” for sustainability can and should be done.
Membrane-based gas transfer: an environmental engineering laboratory
Authors: Kilduff J. , Liu J.X. , Komisar S.J.
Published: May 2018

We propose an educational experience in which students design a membrane gas transfer reactor, construct a bench-scale version in the laboratory, and employ the reactor to measure mass transfer coefficients. The membrane reactor is useful for teaching mass transfer principles because the mass transfer interface is well defined and easily observed. The system can be modeled successfully using straightforward mathematics. The reactor can be designed and constructed by students, using the mathematical model as a basis, providing insight into the physical meaning of model parameters. The proposed membrane system can be readily operated to obtain data that can be employed to develop or modify existing mass transfer correlations. This can provide students with significant insight into the development of mass transfer correlations and how the constants in such correlations are typically determined. These features help promote a deeper understanding of mass transfer principles.
Environmental management master's programme in Kazakhstan: development and operation
Authors: Istamkulov M.R. , Heaven S. , Druz N.N. , Tanton T.W.
Published: May 2018

The paper looks at the origins of the environmental management master's programme in Kazakhstan course and its development over the 7 years for which it has operated. It considers the difficulties of teaching, in particular issues covering the diverse range of topics covered, the need for staff training and development and how this has been approached, and the need to gain financial aid to support the students. Details are given of how students are selected, the range of backgrounds and geographical regions from which they come, and the types of employment they take on graduation. In total 110 students have benefited from the course which has proved an attractive alternative to overseas study.
A kinetic study of enhancing effect by phenolic compounds on the hydroxyl radical generation during ozonation
Authors: Han Y.-H. , Ichikawa K. , Utsumi H.
Published: May 2018

Ozone decomposition in aqueous solution proceeds through a radical type chain mechanism. These reactions involve the very reactive and catalytic intermediates O2- radical, OH radical, HO2 radical, OH-, H2O2, etc. OH radical is proposed as an important factor in the ozonation of water among them. In the present study, the enhancing effects of several phenolic compounds; phenol, 2-, 3-, 4-monochloro, 2,4-dichloro, 2,4,6-trichlorophenol on OH radical generation were mathematically evaluated using the electron spin resonance (ESR)/spin-trapping technique. OH radical was trapped with a 5,5-dimethyl-1-pyrroline-Noxide (DMPO) as a stable adduct, DMPO-OH. The initial velocities of DMPO-OH generation in ozonated water containing phenolic compounds were quantitatively measured using a combined system of ESR spectroscopy with stopped-flow apparatus, which was controlled by homemade software. The initial velocities of DMPO-OH generation increased as a function of the ozone concentration. The relation among ozone concentration, amount of phenolic compounds and the initial velocity (ν0) of DMPO-OH generation was mathematically analyzed and the following equation was obtained, ν0 (10-6 M/s) = (A′ × [PhOHs (10-9M)] + 0.0005) exp (60 × [ozone (10-9 M)]). The equation fitted very well with the experimental results, and the correlation coefficient was larger than 0.98.
Use of microwave pretreatment for enhanced anaerobiosis of secondary sludge
Authors: Park B. , Ahn J.-H. , Kim J. , Hwang S.
Published: May 2018

This work elucidates the effects of pretreatment of secondary sludge by microwave irradiation on anaerobic digestion. The soluble chemical oxygen demand (COD) concentration increased up to 22% as microwave irradiation time increased, which indicated the sludge particles disintegrated. Three identical automated bioreactors with working volume of 5 l were used as anaerobic digesters at mesophilic temperature (35°C). The reactors were separately fed with sludge with microwave pretreated- and controlsludge at different hydraulic retention times (HRT). The volatile solid (VS) reduction in the control operation was approximately 23.2 ± 1.3%, while it was 25.7 ± 0.8% for the reactors with the pretreated sludge. The average biogas production rate with the pretreated sludge at 8, 10, 12, and 15 days HRTs was 240 ± 11, 183 ± 9, 147 ± 8, and 117 ± 7 ml/l/d respectively, while those with the control sludge were134 ± 12 and 94 ± 7 ml/l/d at 10 and 15 days HRTs. Maximum rates of COD removal and methane production with the pretreated sludge were 64% and 79% higher than those of the control system, respectively.
Acidic and hydrogen peroxide treatment of polyaluminum chloride (PACL) sludge from water treatment
Authors: Kwon J.H. , Park K.Y. , Park J.H. , Lee S.H. , Ahn K.H.
Published: May 2018

The water treatment sludge including coagulants cannot be easily removed by conventional dewatering methods. The possibility of hydrogen peroxide (H2O2) oxidation as a pretreatment to enhance the dewaterability of polyaluminum chloride (PACl) sludge from water works was investigated. H2O2 treatment alone was not effective but H2O2 treatment under acidic condition significantly reduced both the cake water content and specific resistance to filtration (SRF), indicating the enhancement of dewaterability and filterability. The filterability after acid/H2O2 treatment was comparable to polymer conditioning and even more dewatered cake than polymer conditioning was produced. By H2O2 combined with sulfuric acid (H2SO4), leached iron caused Fenton's reaction, which showed a potential to significantly reduce the amount of solids mass and to produce more compact cake with higher filterability.
Statistical comparison of the triangle test and the two-of-five test for taste and odor evaluation
Authors: Gallagher D.L.
Published: May 2018

The Triangle test and 2-of-5 test are compared for their ability to evaluate tastes and odors in water and wastewater utilities. Both tests have varying statistical sensitivities. The 2-of-5 test is more sensitive and more powerful than the Triangle test, and generally requires fewer panelists for the same level of statistical confidence. This paper presents a method for determining the number of panelists for either test, and compares the results.
Development of extraction procedures for the analysis of polycyclic aromatic hydrocarbons and organochlorine pesticides in municipal sewage sludge
Authors: Ahmad U.K. , Ujang Z. , Woon C.H. , Indran S. , Mian M.N.
Published: May 2018

Land application of sludge as fertilizers is a way of disposal and recycling of sludge. However, public concern has arisen due to the fact that organic contaminants in sludge may ultimately enter the food chain. Hence the need arises to analyse the organic contaminants such as PAHs and OCPs in sludge. In this study, Soxhlet was utilised as the extraction method and the extracts subjected to extensive cleanup via either silica columns or solid phase extraction cartridges prior to analysis using gas chromatography or high performance liquid chromatography. Sludge samples were collected from the drying beds of oxidation ponds in three locations in South Johore. OCPs such as heptachlor, dieldrin and pp-DDT were detected in low amounts (52-159 mg/kg) whereas PAHs such as naphthalene, phenanthrene, fluoranthene and benzo(a)pyrene were detected in the range of 0.2-5.5 mg/kg dry mass. Subcritical water extraction (SWE) recovery studies of PAHs were also performed from spiked sludge samples. Although a recovery range of 41-68% was obtained using the SWE method, the results indicated the usefulness of the technique as an alternative to Soxhlet extraction for the analysis of PAHs in sludge samples.
Materials used in drinking water distribution systems: contribution to taste-and-odor
Authors: Tomboulian P. , Schweitzer L. , Mullin K. , Wilson J. , Khiari D.
Published: May 2018

In order to assist drinking water utilities with identifying the possible sources and causes of taste-and-odor conditions associated with materials used in distribution systems, we evaluated information from case studies and a database from the National Sanitation Foundation (NSF), International. This database identified chemicals that had leached from drinking water system components during testing of materials under ANSI/NSF Standard 61, which provides information to water utilities on potential taste-and-odor and health concerns from the use of new materials. The data were arranged to provide a process for locating the potential source of a taste-and-odor event. After a sensory analysis is conducted on the drinking water samples, the descriptor can be matched with categories on the "Drinking Water Taste and Odor Wheel 2000" in order to suggest the candidate material.
Municipal sludge management and disposal in South Korea: Status and a new sustainable approach
Authors: Ahn Y.-H. , Choi H.-C.
Published: May 2018

Based on figures from 2002, 5,216 ton/d of the municipal sludge is produced from 184 large municipal wastewater treatment plants in 111 cities with total treatment capacity of 19,229,745 m3/d. Even though the large amount of sludge disposal has depended greatly on ocean disposal and landfills until recently, the fraction of sludge reuse has gradually increased from 2.7% to 7%, since 1991. Due to a need of resources recovery from the sludge, high cost requirement of incineration and legislative regulation, recent new research is mainly focused on resources recovery and its reuse from the municipal sludge, such as high performance acid fermenter with pathogen reduction, crystallization (struvite and hydroxyapatite) using waste lime, cofermentation of municipal sludge with food waste, aerobic composting with P crystallization, vermistabilization, lime treatment, etc. Current research and practical activities with some efforts for the new technical development as well as environmental law and regulation are reviewed.
The effect of oxidants on 2-MIB concentration with the presence of cyanobacteria
Authors: Tung S.-C. , Lin T.-F. , Liu C.-L. , Lai S.-D.
Published: May 2018

In this study, the effect of three oxidants, sodium hypochlorite, potassium permanganate, and ozone, were tested for the removal of 2-MIB with presence of cyanobacteria. Algae in water samples from the source water of Feng-Shen waterworks (FSW), Taiwan were cultivated at 30¡C with continuous light at an intensity between 2,500 and 3,400 lux. During the cultivating process, water samples were analyzed for nutrients, light absorbance at 665nm (A665), and 2-MIB concentration. The 2-MIB concentrations within the incubated samples increased to as high as 1,000 ng/L to 2,000 ng/L, although no extra nutrients were added to the raw water. After 2 to 3 days incubation, the intracellular 2-MIB concentration was as high as 70% of the total 2-MIB in the samples. The algae that developed were mainly cyanobateria, and more than 90% belonged to the Genus Oscillatorias. An almost 100% removal of both 2-MIB and geosmin in the raw water was observed after ozonation for 10 minutes at a dosing rate of 0.91 mg/l-min. Chlorine and permanganate were much less effective, both removing only about 11% of the 2-MIB within 60 minutes at oxidant concentration of 10 mg/l. Oxidation of the cultivated samples showed that chlorine and permanganate may damage algae cells causing them to release intracellular 2-MIB. During the 60 minutes of reaction time, the total 2-MIB concentrations (intracellular plus dissolved) varied by no more than 10%, however, the ratios between dissolved and total 2-MIB concentrations increased. Two effects of ozonation on the 2-MIB concentration in the cultivated samples were observed when the algae were young, namely 2-MIB release from damaged cells and 2-MIB oxidization. The rates of 2-MIB release and 2-MIB destruction were similar. However, old algae cells were more easily damaged. As a result, intracellular 2-MIB was released faster, and the soluble 2-MIB was destroyed more quickly by ozonation.
Role of oxidants and disinfectants on the removal, masking and generation of tastes and odours
Authors: Bruchet A. , Duguet J.P.
Published: May 2018

This paper summarises the positive and negative effects of the most commonly used oxidants and disinfectants: chlorine, chloramines, chlorine dioxide, potassium permanganate ozone, and advanced oxidation with ozone/hydrogen peroxide on tastes and odours present in natural and drinking waters. The case studies reported illustrate the generation of odorous by-products such as chlorophenols, iodoforms, aldehydes, the masking effect between earthy-musty and chlorinous odours, and the removal of odorous algal metabolites or anthropogenic pollutants by ozone alone or by ozone coupled with hydrogen peroxide.
Effect of blending two treated waters on the organoleptic profile of Barcelona's supply
Authors: Fabrellas C. , Devesa R. , Matia L.
Published: May 2018

Barcelona's drinking water has two distinct origins: the Ter and Llobregat rivers supply the city in a ratio of 35/65. The organoleptic quality of the two waters is very different. Treated water from the Llobregat sometimes has organoleptic problems, whereas the quality of treated water from the Ter is much better. The aim of this paper is to study the effects of blending the two types of water and to determine the best blend of the Ter and Llobregat treated waters in terms of flavour and odour, using the A/not A test and the Flavour Profile Analysis. The optimum blend of Ter and Llobregat water is the blend that contains the highest percentage of Llobregat water without any appreciable loss of the characteristics of Ter water.
Chlorinous flavor perception in drinking water
Authors: Piriou P. , Mackey E.D. , Suffet I.H. , Bruchet A.
Published: May 2018

Chlorinous flavors at the tap are the leading cause of customers' complaints and dissatisfaction with drinking water. To characterize consumer perception and acceptance to chlorinous tastes, extensive taste testing was performed with both trained panelists and average consumers. Taste testing with trained panelists showed that chlorine perception is underestimated by disinfectant flavor thresholds reported in the literature. However, trained panelists significantly overestimate the average consumer's ability to perceive chlorine. In addition, consumer perception seems to be influenced by the chlorination practices of the country they live in. Among water quality characteristics that may influence chlorine perception, temperature was not found to induce any significant change. The influence of total dissolved solids (TDS) on chlorine perception remains unclear and, as reported elsewhere, background tastes such as musty, may significantly impact chlorine threshold.
The SBR and its biofilm application potentials
Authors: Wilderer P.A. , McSwain B.S.
Published: May 2018

Twenty plus years of experience, innovation, and research in the field of biological wastewater treatment and biofilm applications lead to the conclusion that biofilms are in many cases more desirable in reactors than suspended activated sludge. Biofilm reactors can provide very long biomass residence times even when the hydraulic influent loading is low. This makes them particularly suitable when treatment requires slow growing organisms with poor biomass yield or when the wastewater concentration is too low to support growth of activated sludge flocs. Regardless of the settling characteristics of biological aggregates or the hydraulic influent loading the metabolic activity in the reactor can be maintained at a high level. This paper reviews the application of biofilms in sequencing batch reactor (SBR) systems to treat non-readily biodegradable substrates, volatile organic waste constituents, complex waste streams requiring co-metabolism, and particulate wastewaters. Recent research using the SBR to form aerobic granular sludge as a special application of biofilms is also discussed.
On-line monitoring for control of a pilot-scale sequencing batch reactor using a submersible UV/VIS spectrometer
Authors: Langergraber G. , Gupta J.K. , Pressl A. , Hofstaedter F. , Lettl W. , Weingartner A. , Fleischmann N.
Published: May 2018

A submersible UV/VIS spectrometer was used to monitor a pilot-scale sequencing batch reactor (SBR). The instrument utilises the whole UV/VIS range between 200 and 750 nm. With just one single instrument nitrate, organic matter and suspended solids can be measured simultaneously. The spectrometer is installed directly in the reactor, measures in real-time, and is equipped with an auto-cleaning system using pressured air. The paper shows the calibration results for measurements in the SBR tank, time series for typical SBR cycles, and proposes possible ways for optimisation of the operation by using these measurements.
Rate of nitrate production during a two-stage nitrification batch reaction
Authors: Pratt S. , Gapes D. , Yuan Z. , Keller J.
Published: May 2018

The two steps of nitrification, namely the oxidation of ammonia to nitrite and nitrite to nitrate, often need to be considered separately in process studies. It has been assumed that these two reactions can be described by single Monod models. In this paper, the suitability of the single Monod model for describing nitrite oxidation to nitrate is discussed. The measured rate of nitrate production during a batch reaction is presented. For the system studied it was found that nitrate production actually increased after the completion of ammonia oxidation. It is suggested that the reason for the increase was a combination of: (i) likely competition for oxygen when both substrates were present, and (ii) a decrease in ammonia inhibition of nitrite oxidisers with the removal of ammonia. The result is that a single Monod expression (based on nitrite as the substrate) could not be used to describe nitrate production. In these types of systems the consequence of oxygen limitation and substrate inhibition should also be considered.
Optimal but robust N and P removal in SBRs: a model-based systematic study of operation scenarios
Authors: Sin G. , Insel G. , Lee D.S. , Vanrolleghem P.A.
Published: May 2018

A systematic approach to determine the optimal operation strategy for nitrogen (N) and phosphorus (P) removal of sequencing batch reactors (SBRs) has been developed and applied successfully to a lab-scale SBR. The methodology developed is based on using a grid of possible scenarios to simulate the effect of the key degrees of freedom in the SBR system. The grid of scenarios is simulated using a calibrated ASM2dN model developed and calibrated in a previous study. Effluent quality in combination with a robustness index for each of the scenarios is used to select the best scenario. With the best scenario, it is possible to improve/increase the current performance of the SBR system by around 54% and 74% for N and P removal respectively.
Integration of chemical and biological oxidation in a SBBR for tannery wastewater treatment
Authors: Di Iaconi C. , Bonemazzi F. , Lopez A. , Ramadori R.
Published: May 2018

This paper reports the results of an investigation aimed at evaluating the laboratory-scale performance of an innovative process for treating tannery wastewater. In this process, biological degradation, carried out in a sequencing batch biofilm reactor (SBBR), is combined with chemical oxidation by ozone. Tannery wastewater treatment was carried out, at laboratory scale, on a real primary effluent coming from a centralised plant treating wastewater produced by a large tannery district in Northern Italy. SBBR performance both without and with ozonation, was assessed with very satisfactory results. In particular, in the latter instance the recorded COD, TKN and TSS average removals, (96%), (92%) and (98%) respectively, allowed the maximum allowable concentration values fixed by the Italian regulation in force to be achieved without any additional polishing step. During the investigation biofilm properties (biofilm concentration and biofilm density) and flow dynamics aspects (head loss, shear stress, bed porosity) were also studied. A major feature of the process is that, with or without ozonation, it was characterised by very low specific sludge production (0.05 kgVSS/kgCODremoved) and high biofilm density (i.e. 87-122 gVSS/Lsludge) both contributing to a rather high biofilm concentration (i.e. 31-44 gTSS/Lfilter).
Demonstration of enhanced nutrient removal at two full-scale SBR plants
Authors: Peters M. , Newland M. , Seviour T. , Broom T. , Bridle T.
Published: May 2018

The efficacy of sequencing batch reactors (SBRs) to provide high levels of biological nutrient removal has been extensively demonstrated around the world. Environmental Solutions International (ESI) has now constructed over 20 full-scale SBR plants and has confirmed that nutrient removal is enhanced via the process of simultaneous nitrification and denitrification. Over 18 months of operational data from two plants, operating in distinctly different catchments, processing an average of between 2,000 and 2,500 m3/d of wastewater, has clearly shown the efficacy and robustness of the ESI SBR-BNR process. Median effluent total nitrogen and total phosphorus values of 3 mg/L and <0.6 mg/L, respectively, were demonstrated over the 18-month period. This high level of nutrient removal is attributed to the design of the bio-selector which maximises carbon storage for the subsequent denitrification reactions, the effective aeration control which ensures no over-aeration during the air-on cycle as well as the level of operational control provided at these two plants.
Production of class A biosolids with anoxic low dose alkaline treatment and odor management
Authors: Abu-Orf M.M. , Brewster J. , Oleszkiewicz J. , Reimers R.S. , Lagasse P. , Amy B. , Glindemann D.
Published: May 2018

The feasibility of full-scale anoxic disinfection of dewatered and digested sludge from Winnipeg, Manitoba with low lime doses and lagoon fly ash was investigated to determine if a class A product could be produced. Lime doses of 50 g, 100 g, and 200 g per kg of biosolids (dry) were used along with fly ash doses of 500 g, 1,000 g, and 1,500 g per kg of biosolids (dry). The mixed product was buried in eight-10 cubic metre trenches at the West End Water Pollution Control Center in Winnipeg. The trenches were backfilled with dirt and trapped to simulate anoxic conditions. Sampling cages were packed with the mixed product and pathogens non-indigenous to Winnipeg's biosolids. The cages were buried amongst the mixed biosolids in the trench. The non-indigenous pathogens spiked in the laboratory were the helminth Ascaris suum and the enteric virus reovirus. Samples were removed at days 12, 40, 69, 291, and 356 and were tested for the presence of fecal Coliform, Clostridium perfringens spores, Ascaris suum eggs, and reovirus. The pH, total solids, and free ammonia content of the mixed product were also determined for each sample. Odor was quantified for samples at both 291 and 356 days. Fecal Coliform bacteria and reovirus were completely inactivated for doses as low as 100 g lime per kg biosolids (dry) and 50 g lime + 500 g fly ash per kg biosolids (dry). Spores of the bacteria C. perfringens experienced a 4-log reduction when treated with 100 g lime per kg biosolids and a 5-log reduction when treated with doses as low as 50 g lime + 500 g fly ash per kg biosolids (dry) after 69 days. Ascaris eggs were completely inactivated in 5 gram packets for all treatments involving 100 g lime per kg biosolids (dry) after 69 days. Class A pathogen requirements were met for all treatments involving a lime dose of at least 100 g per kg biosolids. The odor potential from the produced biosolids is also assessed.
Digestion of sludge and organic waste in the sustainability concept for Malmö, Sweden
Authors: la Cour Jansen J. , Gruvberger C. , Hanner N. , Aspegren H. , Svärd Â
Published: May 2018

Anaerobic digestion of sludge has been part of the treatment plant in Malmö for many years and several projects on optimisation of the digestion process have been undertaken in full scale as well as in pilot scale. In order to facilitate a more sustainable solution in the future for waste management, solid waste organic waste is sorted out from households for anaerobic treatment in a newly built city district. The system for treatment of the waste is integrated in a centralised solution located at the existing wastewater treatment plant. A new extension of the digester capacity enables separate as well as co-digestion of sludge together with urban organic waste from households, industry, restaurants, big kitchens, food stores, supermarkets, green markets etc. for biogas production and production of fertiliser. Collection and pre-treatment of different types of waste are in progress together with examination of biogas potential for different types of organic waste. Collection of household waste as well as anaerobic digestion in laboratory and pilot scale has been performed during the last year. It is demonstrated that organic household waste can be digested separately or in combination with sludge. In the latter case a higher biogas yield is found than should be expected from digestion of the two materials separately. Household waste from a system based on collection of organic waste from grinders could be digested at mesophilic conditions whereas digestion failed at thermophilic conditions.
Phosphorus recovery - an overview of potentials and possibilities
Authors: Balmér P.
Published: May 2018

The endeavour towards a sustainable society has led to an interest in the recovery and recirculation or reuse of phosphorus from wastewater among environmentalists and politicians. In a recent interdisciplinary investigation commissioned by the Swedish Environmental Protection Agency, an attempt was made to evaluate different possibilities to recover phosphorus from wastewater or its fractions; systems based on source separation of urine or of combined toilet wastes, on the extraction of phosphorus from sludge, from ashes after incineration of sludge or from wastewater as well as the direct recirculation of hygienised digested and dewatered sludge were studied. Aspects like technology, environmental effects, resource economy, economy, markets, organisational aspects and user aspects were studied. In this overview the potential and possibility to recover and recirculate phosphorus from wastewater is discussed, mainly based on the findings in this investigation.
Experience and lessons learned from sewage sludge pyrolysis in Australia
Authors: Bridle T.R. , Skrypski-Mantele S.
Published: May 2018

Management of sewage sludge via “publicly acceptable” methods is becoming increasingly difficult, primarily due to health and environmental concerns with respect to reuse of the product in agriculture. Consequently thermal processes are gaining popularity with significantly increased interest being shown in pyrolysis and gasification processes, due to their “non-incineration status”. One such process is the ENERSLUDGE™ technology which has been developed and commercialised by Environmental Solutions International Ltd (ESI). The world's first commercial ENERSLUDGE™ plant is located at the Subiaco Wastewater Treatment Plant (WWTP) that was handed over to the client, the Water Corporation of Western Australia in June 2001. Extensive design knowledge and operational experience has now been accumulated from this commercial pyrolysis facility and future applications of the technology will benefit immensely from the lessons learned and experience gained from this facility.
Watershed monitoring and modelling and USA regulatory compliance
Authors: Turner B.G. , Boner M.C.
Published: May 2018

The aim of the Columbus program was to implement a comprehensive watershed monitoring-network including water chemistry, aquatic biology and alternative sensors to establish water environment health and methods for determining future restoration progress and early warning for protection of drinking water supplies. The program was implemented to comply with USA regulatory requirements including Total Maximum Daily Load (TMDL) rules of the Clean Water Act (CWA) and Source Water Assessment and Protection (SWAP) rules under the Safe Drinking Water Act (SDWA). The USEPA Office of Research and Development and the Water Environment Research Foundation provided quality assurance oversight. The results obtained demonstrated that significant wet weather data is necessary to establish relationships between land use, water chemistry, aquatic biology and sensor data. These measurements and relationships formed the basis for calibrating the US EPA BASINS Model, prioritizing watershed health and determination of compliance with water quality standards. Conclusions specify priorities of cost-effective drainage system controls that attenuate stormwater flows and capture flushed pollutants. A network of permanent long-term real-time monitoring using combination of continuous sensor measurements, water column sampling and aquatic biology surveys and a regional organization is prescribed to protect drinking water supplies and measure progress towards water quality targets.
Towards a common benchmark for long-term process control and monitoring performance evaluation
Authors: Rosen C. , Jeppsson U. , Vanrolleghem P.A.
Published: May 2018

The COST/IWA benchmark simulation model has been available for seven years. Its primary purpose has been to create a platform for control strategy benchmarking of biological wastewater treatment processes. The fact that the benchmark has resulted in more than 100 publications, not only in Europe but also worldwide, demonstrates the interest for such a tool in the research community. In this paper, an extension of the benchmark simulation model no. 1 (BSM1) is proposed. It aims at facilitating evaluation of two closely related operational tasks: long-term control strategy performance and process monitoring performance. The motivation for the extension is that these two tasks typically act on longer time scales. The extension proposed here consists of 1) prolonging the evaluation period to one year (including influent files), 2) specifying time varying process parameters and 3) including sensor and actuator failures. The prolonged evaluation period is necessary to obtain a relevant and realistic assessment of the effects of such disturbances. Also, a prolonged evaluation period allows for a number of long-term control actions/handles that cannot be evaluated in a realistic fashion in the one week BSM1 evaluation period. In the paper, models for influent file design, parameter changes and sensor failures, initialization procedure and evaluation criteria are discussed. Important remaining topics, for which consensus is required, are identified. The potential of a long-term benchmark is illustrated with an example of process monitoring algorithm benchmarking.