bluuebunny/crossref_metadata_2025 huggingface dataset:
Inhibitory effects of long-chain fatty acids on VFA degradation and β-oxidation
Authors: Shin H.-S. , Kim S.-H. , Lee C.-Y. , Nam S.-Y.
Published: May 2018

The inhibitory effects of major long-chain fatty acids (LCFA), which have 16 or 18 carbons, not only on acetate degradation, but also on propionate degradation and β-oxidation were examined in anaerobic serum bottle tests at 35°C with the acclimated granular sludges. A modified Gompertz equation described cumulative methane production to assess the rates of VFA degradation and β-oxidation, which were applied to a simplified noncompetitive model and a simplified substrate inhibition model, respectively. The specific methane production rates on acetate decreased as LCFA concentration increased, which was in good agreement with the noncompetitive inhibition model. Unsaturated oleate (C18:1) and linoleate (C18:2) were more inhibitory than saturated stearate (C18:0) and palmitate (C16:0) on acetate degradation. LCFA inhibition on propionate degradation was similar to that for acetate; however, propionate degradation was less inhibited than acetate degradation. β-oxidation was the rate-limiting step in LCFA degradation in most cases. As LCFA concentration increased, β-oxidation rate reached the maximum value, and then decreased, which confirmed the substrate inhibition of LCFA. Oleate, the most abundant LCFA in wastewater, could be degraded more quickly than saturated LCFA containing the same or even less carbon in spite of relatively high toxicity on acetate degradation.
Effects of sediment phosphorus release associated with the density current on water quality of a subtropical and deep reservoir in Taiwan
Authors: Chen Y.-J. , Wu S.-C.
Published: May 2018

It was found that the increase of sediment P release in the anoxic state associated with the density current initiated by the cold front in the winter was the cause of the deterioration of the water quality of the subtropical, noncalcareous and deep reservoir, Feitsui Reservoir, in recent years. A mathematical model including the analytical solutions of the transport of the density current combined with a simple 2-layered water quality model has been established, describing the hydrodynamics and the water quality variation of the reservoir well. The continued sediment release of P in the anoxic state (from October to March) is an important P source and should be carefully assessed and controlled to reduce the impact of the internal loading of P incorporated with the density current on the water quality in future years.
A multiobjective model for non-point source pollution control for an off-stream reservoir catchment
Authors: Kao J.-J. , Chen W.J.
Published: May 2018

Phosphorus loads from agricultural non-point source pollution (NPSP) significantly degrade reservoir water quality, making adequate control of agricultural NPSP necessary for improving the water quality. Controlling NPSP is generally accomplished using various Best Management Practices (BMPs). The present study applies the Agricultural Non-Point Source Pollution (AGNPS) model to simulate NPSP loading and BMP efficiencies and establishes an enhanced multiobjective mixed-integer programming model for NPSP control strategy analyses based on these results. Cost, phosphorus load, sediment load and equity are the four major objectives considered. A case study for the Posan reservoir is presented. Four commonly proposed and applicable BMPs are chosen. Non-inferior solutions obtained using the constraint method and trade-off relationships among different control objectives are described and discussed. Compared with a previously proposed fertilizer control model, results show that the model established herein is more cost-effective and achieves better phosphorus and sediment loading reduction and equity goals. Furthermore, the current model is expected to facilitate decision-making analysis for development of an appropriate cost-sharing program to encourage adoption of appropriate BMPs by farmers.
Removal of metals from aqueous solutions using natural chitinous materials
Authors: Rae I.B. , Gibb S.W.
Published: May 2018

Four naturally derived chitinous materials, commercial cryogenically milled carapace (CCMC), mechanically milled carapace (MMC), chitin and chitosan, were assessed for their ability to remove a range of alkali, alkaline earth, transition and heavy metals from aqueous media in flow-through column trials. The materials showed a poor affinity for the alkali metals and alkaline earth metals but significantly greater affinity for transition and heavy metals. In general, chitin was the least efficient material for removal of transition and heavy metals (≈35%) while chitosan was most effective (>99%). CCMC and MMC both removed >90% of transition and heavy metals tested from solution. Batch studies conducted using copper as a reference metal demonstrated that removal was dependent on a number of variables including pH, contact time, particle size, metal concentration, metal type and the physio-chemical characteristics of the materials. Detailed analysis of the results from these studies indicate that removal is a complex process and that metals can be sequestered from solution by a number of mechanisms including adsorption, absorption and precipitaion.
Controlling nitrogen removal using redox and ammonium sensors
Authors: Cecil D.
Published: May 2018

At the Ejby Mølle WWTP (300,000 PE) operated by the Odense Water Ltd. a system of aeration control which combines ammonium concentration and redox potential has proven itself as a method of reducing nitrogen levels in the effluent. The nitrogen removal process at this plant proceeds in parallel aeration tanks that alternate between periods of aeration and denitrification. At the same time influent is redirected from one tank to the other such that influent and effluent is primarily to and from the tank where denitrification is going on. The aeration stops and the tanks open and close when the ammonium concentration reaches its set point. Aeration is restarted again when redox potential drops to its low set point or when ammonium reaches its upper set point. The average total nitrogen concentration in the effluent from the Ejby Mølle WWTP went from 4.7 down to 2.1 mgN/l after this control system was implemented. Not all of this reduction can be explained by better control. However we believe that at least 1 mgN/L of the reduction and probably more was the result of the control system based on the combination of ammonium and redox sensors.
Nitrification and denitrification using a single biofilter packed with granular sulfur
Authors: Kim J.-S. , Hwang Y.-W. , Kim C.-G. , Bae J.-H.
Published: May 2018

This study was performed to develop a granular sulfur packed nitrification/denitrification process employing a uniquely designed single biofilter, which treated a relatively low carbon loaded domestic wastewater taken from a primary clarifier at a municipal wastewater treatment facility. The system was tested on varying experimental conditions, e.g. inflow flow, organic load and nitrogen load. Regardless of flow rate being increased, SS and COD was unvaryingly removed up to 90 and 80%, respectively. Moreover, TKN was also decomposed up to 90%. Increase in COD load gradually led to escalating level of non-biodegradable compounds observed in effluent. Nitrification was accomplished as high as 92%, whereas denitrification was achieved up to approximately 87%. For a while, nitrification and denitrification were observed at 0.65 and 0.55 kg/m3áday, respectively. Eventually, T-N was decomposed as high as 46%. It was concluded that granular sulfur can be used for not only electron donor, but also for a media to properly treat low carbon loaded wastewater and to filter SS efficiently.
Molecular biological methods (DGGE) as a tool to investigate nitrification inhibition in wastewater treatment
Authors: Kreuzinger N. , Farnleitner A. , Wandl G. , Hornek R. , Mach R.
Published: May 2018

Incomplete nitrification at an activated sludge plant for biological pre-treatment of rendering plant effluents led to a detailed investigation on the origin and solution of this problem. Preliminary studies revealed that an inhibition of ammonia oxidising microorganisms (AOM) by process waters of the rendering plant was responsible for the situation. We were able to show a correlation between the existence of specific AOM and nitrification capacity expressed as oxygen uptake rate for maximal nitrification (OURNmax). Only Nitrosospira sp. was found in the activated sludge of the rendering plant and another industrial wastewater treatment plant with problems in nitrification, while reference plants without nitrification problems showed Nitrosomonas spp. as the predominant ammonia oxidising bacteria. By accompanying engineering investigations and experiments (cross-feeding experiments, operation of a two-stage laboratory plant) with molecular biological methods (DGGE - Denaturing Gradient Gel Electrophoresis) we were able to elaborate an applicable solution for the rendering plant. Laboratory experiments with a two-stage process layout finally provided complete nitrification overcoming the inhibiting nature of process waters from the rendering plant. DGGE analysis of the second stage activated sludge from the laboratory plant showed a shift in population structure from Nitrosospira sp. towards Nitrosomonas spp. simultaneous to the increase of nitrification capacity. Nitrification capacities comparable to full-scale municipal wastewater treatment plants could be maintained for more than two months. As the design of wastewater treatment plants for nitrification is linked to the growth characteristics of Nitrosomonas spp., established criteria can be applied for the redesign of the full-scale plant.
Polyhydroxyalkanoate form and polyphosphate regulation: keys to biological phosphorus and glycogen transformations?
Authors: Randall A.A. , Chen Y. , Liu Y.-H. , McCue T.
Published: May 2018

Experimental studies with both synthetic and real domestic wastewater showed that poly-3-hydroxy-butyrate (3HB) and poly-3-hydroxy-valerate (3HV) formed in direct proportion to the acetate/propionate (Ace/Pro) ratio of the influent wastewater during Enhanced Biological Phosphorus Removal (EBPR). Acetic acid resulted in higher anaerobic phosphorus (P) release, polyhydroxyalkanoate (PHA) yield, 3HB content, and glycogen (CH) degradation. Linear regression showed that anaerobic P release (Prel) and CH degradation (CHdeg) were both a function of Ace→3HB, but not of Pro→3HV. Aerobic P uptake (Pup) correlated best with preceding Prel rather than PHA (but note Prel correlated with Ace→3HB). Aerobic CH formation (CHform) correlated best with CHdeg and 3HB. The results imply the acetate/propionate content of influent has a major influence on PHA, CH, and P transformations. Short-term increases in acetic or propionic acid increased Prel, but were always offset by corresponding changes in Pup to yield the same net P removal as the control reactor. Thus net P removal, and EBPR process performance, was probably a function of the population selected (i.e. XPAO fraction) during long-term cultivation.
Integral and unified model for the sewer and wastewater treatment plant focusing on transformations
Authors: Huisman J.L. , Krebs P. , Gujer W.
Published: May 2018

The urban drainage cycle is a very complex system with many interacting processes. Models are a great help to test different scenarios and improve the understanding of this system. At present, good models exist for the hydrodynamics of the sewer systems, for the biological conversions in the wastewater treatment plant (ASM 1 to 3) and for the receiving water (RWQM1). However, the traditional transport and conversion models for the sewer system are incompatible with the ASM definitions, making it difficult to link the models to come an integral and unified urban drainage model.

In this work, a new sewer system model that is based on ASM3 has been coupled to an advanced nutrient removal model for the wastewater treatment plant. As both models are based on ASM3, they are unified in their definitions of the state variables and processes. This new combination has been used to test different scenarios and to test the influence of the sewer system on the treatment plant.
Effect of floc size and structure on biosolids capillary suction time
Authors: Guan J. , Amal R. , Waite T.D.
Published: May 2018

Both size and structure of wastewater solids (biosolids) have been hypothesised to have an impact on the dewaterability of these solids yet very little data exists to validate this hypothesis or to elucidate the relative effects of size and structure. We have recently undertaken studies in which the size and structure of activated sludge flocs were altered in a controlled manner and the dewaterability of resultant flocs examined using the well established capillary suction time (CST) test. A small angle light scattering method was applied for the determination of activated sludge floc size and structure. The results obtained in this work show that floc structure is a major determinant of capillary suction time. In some instances, flocs have almost double the median (D(4,3)) size but possess similar fractal dimensions and similar CST values.
Integrated urban water planning: big picture planning is good for the wallet and the environment
Authors: Anderson J. , Iyaduri R.
Published: May 2018

The demands on governments and local authorities are changing in response to community expectations for environmentally sustainable outcomes. To reverse declining water quality in rivers and ensure sustainable use in the 21st century, the State Government in New South Wales has introduced a package of Water Reforms. The introduction of integrated water, sewerage and drainage planning is one of the Water Reform initiatives. Traditionally, government and local authorities have managed their water supply, sewerage and stormwater drainage systems as separate entities. Integrated urban water planning is a structured planning process to evaluate concurrently the opportunities to improve the management of water, sewerage and drainage services within an urban area in ways which are consistent with broader catchment and river management objectives. The New South Wales Department of Land & Water Conservation (DLWC) has developed an integrated urban water planning process through a number of recent pilot studies. The process links urban water management objectives to overall catchment and river management objectives. DLWC is currently developing a set of guidelines for integrated urban water plans. DLWC has developed the Integrated Urban Water Planning methodology through three pilot studies in the New South Wales towns of Finley, Goulburn and Bombala. The pilot studies have shown that an integrated approach to water, sewerage and stormwater planning can identify opportunities that are not apparent when separate strategies are developed for each service. The result is better-integrated, more sustainable solutions, and substantial cost savings for local communities.
An integrated water resources management approach for the River Spree and its catchment
Authors: Schlaeger F. , Schonlau H. , Köngeter J.
Published: May 2018

In this paper a concept of an integrated water quality model for a river catchment area is presented. The main focus is directed to the development of a water quality module for rivers. Necessary simplifications for calculation of hydraulics and water quality will be explained. Furthermore, by first simulation results possible applications of the model are presented.
Water quality management in the Kaoping River watershed, Taiwan
Authors: Kao C.-M. , Chen K.-F. , Liao Y.-L. , Chen C.-W.
Published: May 2018

The Kaoping River basin is the largest and the most intensively used river basin in Taiwan. It is 171 km long and drains a catchment of more than 3,250 km2. Based on the current water quality analysis, the Kaoping River is heavily polluted. Concern about the deteriorating condition of the river led the Government of Taiwan to amend the relevant legislation and strengthen the enforcement of the discharge regulations to effectively manage the river and control the pollution. Investigation results demonstrate that both point and non-point source pollutants are now the causes of biochemical oxygen demand (BOD), nutrients, and pathogens in the river. The main water pollution sources are livestock wastewater from hog farms, municipal wastewater, industrial wastewater, non-point source (NPS) pollutants from agricultural areas, and leachate from riverbank landfills. The current daily BOD, NH3-N, and TP loadings to Kaoping River are 74,700, 39,400, and 5,100 kg, respectively. However, the calculated BOD, NH3-N, and TP carrying capacities are 27,700, 4,200, and 600 kg per day. To protect public health and improve the river water quality, a comprehensive management and construction strategy is proposed. The proposed strategy includes the following measures to meet the calculated river carrying capacity: (1) a hog ban in the entire Kaoping River basin, (2) sewer system construction to achieve 30% of connection in the basin within 10 years, (3) removal of 10 riverbank landfills, and (4) enforcement of the industrial wastewater discharge standards. After the implementation of the proposed measures, the water quality should be significantly improved and the BOD and nutrient loadings can be reduced to below the calculated carrying capacities.
Effect of non-aqueous phase liquid on biodegradation of PAHs in spilled oil on tidal flat
Authors: Kose T. , Miyagishi A. , Mukai T. , Takimoto K. , Okada M.
Published: May 2018

Biodegradation rates of polycyclic aromatic hydrocarbons (PAHs) in spilled oil stranded on tidal flats were studied using model reactors to clarify the effects of NAPL on the biodegradation of PAHs in stranded oil on tidal flat with special emphasis on the relationship between dissolution rates of PAHs into water and viscosity of NAPL. Biodegradation of PAHs in NAPL was limited by the dissolution rates of PAHs into water. Biodegradation rate of chrysene was smaller than that for acenaphthene and phenanthrene due to the smaller dissolution rates. Dissolution rates of PAHs in fuel oil C were smaller those in crude oil due to high viscosity of fuel oil C. Therefore, biodegradation rates of PAHs in fuel oil C were smaller than those in crude oil. Biodegradation rates of PAHs in NAPL with slow decrease rate like fuel oil C were slower than those in NAPL with rapid decrease like crude oil. The smaller decrease rate of fuel oil C than crude oil was due to higher viscosity of fuel oil C. Therefore, not only the dissolution rate of PAHs but also the decrease rates of NAPL were important factors for the biodegradation of PAHs.
Emissions of heavy metals into river basins of Germany
Authors: Scherer U. , Fuchs S. , Behrendt H. , Hillenbrand T.
Published: May 2018

The input of seven heavy metals (Cd, Cr, Cu, Hg, Ni, Pb and Zn) into the large river basins of Germany via various point and diffuse pathways were estimated for the period of 1985 through 2000. To quantify the emissions via point sources a nationwide survey on heavy metal data of municipal wastewater treatment plants and industrial direct discharges was carried out. The input via diffuse pathways was calculated using an adapted version of the model MONERIS. This model accounts for the significant transport processes, and it includes a Geographical Information System (GIS) that provides digital maps as well as extensive statistical information. For a comparison of the calculated heavy metal emission with the measured heavy metal load at monitoring stations the losses of heavy metals due to retention processes within the river systems have to be considered. Therefore heavy metal retention was calculated according to the retention functions given by Vink and Behrendt. For the large river basins a good correspondence could be found between estimated and measured heavy metal loads in rivers. The total emission into the North Sea decreased for each metal during the period of 1985 to 2000. The reduction varies between 87% for Hg and 41% for Ni mainly caused by the decline via point sources. Today's emissions of heavy metals into river basins of Germany are dominated by the input via diffuse pathways. The most important diffuse emission pathways are “paved urban areas” and “erosion”.
Pollution potential of oil-contaminated soil on groundwater resources in Kuwait
Authors: Literathy P. , Quinn M. , Al-Rashed M.
Published: May 2018

The only natural freshwater resource of Kuwait occurs as lenses floating on the saline groundwater in the northern part of the country, near to the oil fields. Rainwater is the only means of recharge of this limited groundwater resource. This groundwater is used as bottled drinking water and the fresh groundwater aquifer is considered as a strategic drinking water reserve for Kuwait. As a result of the 1991 Gulf War, the upper soil layer has been widely contaminated with crude oil and crude oil combustion products, which are potential pollutants likely affecting the groundwater resources. Significant efforts have been made to assess this pollution. These included: (a) a soil survey for assessing the soil contamination, and (b) leaching experiments to characterise the mobilization of the soil-associated pollutants. Fluorescence measurement techniques were used during field surveys as well as for laboratory testing. In addition, determination of the total extractable matter (TEM), total petroleum hydrocarbons (TPH), and GC/MS measurement of polyaromatic hydrocarbons (PAHs) were performed for the assessments. The laser induced fluorescence (LIF) measurement, having good correlation with the other laboratory measurements, was proved to provide necessary information for the assessment of the oil-contamination level in the desert soil. The subsequent leaching test with water demonstrated the mobilization of the fluorescing compounds (e.g. PAHs), and the alteration in the leaching characteristics of the contamination during the long-term environmental weathering of the oil.
Effects of seasonal variation in precipitation on estimation of non-point source pollution
Authors: Lin Y.-C. , Kao J.-J.
Published: May 2018

The extent of nonpoint source pollution (NPSP) generated from upstream catchment areas of a reservoir is normally estimated based on a design rainfall. However, rainfall generally varies in different seasons. This seasonal change may significantly influence the estimation of runoff volume and associated NPSP arising within a reservoir watershed. The NPSP management, reservoir operation, and water treatment operation strategies developed based on the estimation will also be altered. This study analyzes the effects of monthly and seasonal variation in precipitation on the estimation of pollution levels from non-point sources in a reservoir watershed. The area studied is the Derchi reservoir watershed located in central Taiwan. This watershed is subdivided into twenty-six sub-watersheds, and the Thiessen method is used to determine the rainfall intensity in each sub-watershed. Runoff pattern and NPSP contributions for each sub-watershed are estimated using the AGNPS model. Results show significant seasonal variation in precipitation; estimated NPSP loads likewise vary significantly over time. Seven- to one hundred-fold differences among monthly and seasonal estimations of phosphorus and sediment loads are observed.
Prevention of odour emergence in sewage networks
Authors: Barjenbruch M.
Published: May 2018

Through increasing central development and through the decrease of specific wastewater production, wastewater systems are more and more prone to odour and corrosion problems. Hydrogen sulphide is produced, particularly in anaerobic flow stretches, which will then escape at turbulent places because of change in the flow direction and create odour harassment. Of particular importance in this respect are the transferring shafts after rising mains. The empirical approaches used for the estimation of the assumed sulphide concentrations yield considerable differences in the calculation and must therefore be used with care.

This report presents a methodology for the co-ordination of odour- and corrosion-reducing measures which also includes the area of complaint management. It is crucially important to fine-tune the necessary measures (for instance the application of operational or chemical/biological methods) to the specific frame conditions.

The practical comparison of the additional dosage of external water, iron and nitrate served to test the efficiency of these methods. The dosage of iron and nitrate led to considerable reductions in H2S content at the transferring shaft. The online measurement of the spectral adsorption coefficient (SAC) could become one control parameter for saving chemicals.

It should be pointed out that it is necessary to consider the relevant measures and effects of odour and corrosion production during the planning stage - from the creation of the development plan of cities and communities. Through the selection of the wastewater disposal method to the planning of details. Moreover, the relevant financial means for these measures must be included in the economic plan.
Real time control of a combined sewer system using radar-measured precipitation - results of the pilot study
Authors: Petruck A. , Holtmeier E. , Redder A. , Teichgräber B.
Published: May 2018

Emschergenossenschaft and Lippeverband have developed a method to use radar-measured precipitation as an input for a real-time control of a combined sewer system containing several overflow structures. Two real-time control strategies have been developed and tested, one is solely volume-based, the other is volume and pollution-based. The system has been implemented in a pilot study in Gelsenkirchen, Germany. During the project the system was optimised and is now in constant operation. It was found, that the volume of combined sewage overflow could be reduced by 5 per cent per year. This was also found in simulations carried out in similar catchment areas. Most of the potential of improvement can already be achieved by local pollution-based control strategies.
Rheology measurement for on-line monitoring of filaments proliferation in activated sludge tanks
Authors: Tixier N. , Guibaud G. , Baudu M.
Published: May 2018

Rheological behaviour of filamentous sludges originated from activated sludge reactors was studied. Filamentous bulking was detected via a hysteresis loop developed from rheograms resulting from increasing-decreasing shear rates. The rheological parameter reduced hysteresis area (rHa), corresponding to the loop area developed by rheograms was used to quantify filamentous bulking. Application to the evolution of several bulkings was carried out and it was shown that filaments proliferation and disappearance were correlated with, respectively, the increasing and decreasing of the value of the parameter rHa. In parallel with rheological measurement, parameters used for the study of sludge quality, such as sludge volume index (SVI) and settling initial flow (F0), were determined for comparison during the evolution of several bulkings. It was shown that rHa was more sensitive to the appearance of filamentous bulking than SVI and F0, therefore it was concluded that detection of filamentous bulking can be shown from rHa.
In situ UV monitoring of wastewater: a response to sample aging
Authors: Baurès E. , Berho C. , Pouet M.-F. , Thomas O.
Published: May 2018

The phenomenon of wastewater sample aging is supposed to be treated with a low temperature autosampler. This work presents two examples of treated wastewater, the quality of which varies with the time of conservation. This evolution may pose some problems with respect to regulation compliance or process control. After the explanation of the mechanisms involved in sample aging, some recommendations are proposed in order to improve the UV off-line measurement of TSS and COD of treated wastewater.
Evaluation of the microbial quality of water supplies to municipal, mining and squatter communities in the Bindura urban area of Zimbabwe
Authors: Nyati H.
Published: May 2018

A survey of the microbiological and chemical quality of water supplies in the Bindura urban and peri-urban area was carried out over a three-year period from January 2000 to July 2003. Bindura is the provincial city of Mashonaland Central, situated 88 km from the national capital, Harare. Large-scale farming and mining activities in the area predispose water bodies to eutrophication and chemical pollutants, raising concerns about the safety of local water supplies. In this study, thermotolerant (faecal) coliform levels, total aerobic bacterial counts and physicochemical profiles were determined for municipal and borehole water as well as water supplies to mining and squatter communities. Although municipal and mining compound water supplies were of satisfactory microbial and chemical quality, borehole water supplies showed a seasonal fluctuation, with higher coliform counts in the wet season from November to March. Stream water supplies to a squatter camp in the peri-urban area consistently recorded coliform levels >1,800/100 mL and total aerobic plate counts of <2.8 × 106 CFU/mL. All cholera incidents recorded in 1999 and 2000 at the Provincial hospital were from peri-urban settlements and surrounding commercial farms while 1,045 to 2,632 cases of dysentery were also reported each year at the provincial hospital during the period 1997-2002.
Detection of infectious pathogenic viruses in water and wastewater samples from urbanised areas
Authors: Sano D. , Watanabe T. , Matsuo T. , Omura T.
Published: May 2018

Regardless of the remarkable improvement in sanitary conditions in urbanised areas, infectious diseases caused by pathogenic viruses in water have been reported year after year. The actual situation for the behaviour of pathogenic viruses in urbanised society should be understood. In this study, infectious enteroviruses and adenoviruses in water and wastewater samples from urbanised areas were investigated. Infectious enteroviruses were continuously detected from sewage and sewage sludge during the summer season. The detection of infectious viruses in sewage and sewage sludge was facilitated by the enzymatic virus elution (EVE) method. The concentration of infectious enteroviruses in positive samples of sewage and sewage sludge was >400 virions/L. Infectious viruses were also detected from water samples at levels >4 virions/L.
Comparison of agar-based methods for the isolation and enumeration of heterotrophic bacteria with the new Multidose IDEXX(tm) SimPlate method
Authors: Vulindlu M. , Charlett A. , Surman S. , Lee J.V.
Published: May 2018

Pour and spread plates are the conventional methods of choice for the isolation and enumeration of heterotrophic microorganisms in treated water supplies. The tests are performed at 22°C and 37°C for 72 h and 48 h respectively. Counts at 22°C are associated with pollution of water systems from external sources, while counts at 37°C are used as an indication of treatment plant performance and the deterioration of the general quality of water. Conventional methods using Yeast Extract Agar for a pour plate and R2A agar for a spread plate were compared with the multidose IDEXXTM SimPlate method for the isolation and enumeration of heterotrophic bacteria in water. SimPlate gave a significantly higher count on average than the conventional methods. The R2A method showed the next highest count, being significantly higher than Yeast Extract Agar. In addition, unlike the pour and spread plate methods, SimPlate was easier to use, reduced labour, and the test results were far easier to read.
Setting up microbiological water reuse guidelines for the Mediterranean
Authors: Bahri A. , Brissaud F.
Published: May 2018

Water reuse is a widespread practice in most Mediterranean countries. Some countries have no wastewater treatment facilities and direct reuse of raw wastewater is occurring while others have a well-established national reuse policy. Water reuse microbiological standards, when existing, significantly differ from one country to another. Some countries have adopted regulations close to the California's Water Recycling Criteria whereas other countries have chosen criteria based on the World Health Organisation (WHO) guidelines. California standards are technologically based requirements aimed at eliminating the presence of pathogens. The WHO guidelines relied on epidemiological evidences though few were available. Their revision on the basis of new epidemiological investigations and quantitative microbiological risk assessment (QMRA) provided by Blumenthal et al., together with added QMRA data, helped proposing Mediterranean guidelines. Acceptable annual risks related to bathing and potable water drinking were taken as benchmarks. This proposal is designed to protect individuals against realistic maximum exposures and to provide minimum and affordable requirements which should constitute the basis of water reuse regulations in every country of the region. Inadequacies of the actual knowledge do not allow a definitive position regarding the guideline limits; other scientific and technical basis are still required.
Water reuse for irrigation from waste water treatment plants with seasonal varied operation modes
Authors: Cornel P. , Weber B.
Published: May 2018

Irrigation periods are usually limited to vegetation periods. The quality requirements for treated wastewater for disposal and for reuse are different. The reuse of water for irrigation allows partly the reuse of the wastewater's nutrients (N and P). Outside the irrigation period the water must be treated for disposal, thus nutrient removal is often required in order to avoid detrimental effects on the receiving surface water body. Only wastewater treatment plants with different operation modes for different seasons can realise these requirements. The nitrification is the most sensitive biological process in the aerobic wastewater treatment process. At low water temperatures the nitrifying bacteria need several weeks to re-start full nitrification after periods without NH4-removal. Therefore it is necessary to develop options for waste water treatment plants which allow a fast re-start of the nitrification process. Based on theoretical considerations and computer simulations of the activated sludge treatment process, one possibility for implementing a wastewater treatment plant with different seasonal operation modes is evaluated.
Prediction of oxygen induced corrosion in industrial waters
Authors: Andijani I. , Turgoose S.
Published: May 2018

This paper reviews available mass transfer correlations and models for the prediction of oxygen corrosion rates in industrial waters. It is shown that one commonly used model predicts corrosion rates many times higher than all the other available approaches. The latter are preferred for prediction of average corrosion rates but allowance should be made for locally high mass transfer rates at, for example, flow disturbances.
Scale and corrosion control with combined dolomite/_calcite filter
Authors: Log T. , Simpson G. , Hanssen H.K. , Robinson M. , Hubble J. , Parsons S.A.
Published: May 2018

Water quality is a major operational issue for boiler operation and control. If the water is hard scale control is required and if it is soft then corrosion control is an issue. Here a two stream boiler test rig has been used to test the effect a fixed bed filter has on the scaling and corrosion properties of both hard and soft waters. The filter effectively controlled the pH, hardness and alkalinity of both waters leading to significant decreases in scale formation and effective control of corrosion.
Test method for evaluation of anti-scale devices for cooling condensers
Authors: Vestergaard J.B.
Published: May 2018

Can new types of anti-scaling devices prevent scaling on condensing pipes in industrial cooling condensers and supersede conventional water treatment? To examine this question a test method has been developed, test rigs have been built and different kinds of anti-scale devices have been tested. As cooling towers are based on an open-air system with evaporation of water they will have higher demands on the effectiveness of the anti-scale devices compared to the closed systems which are typical drinking water systems in buildings. The test method is based on an open-air system. The rigs are mobile and can be used to give an indication of whether it is possible to treat the local water with an anti-scale device. The result of the test is a scaling rate and a germination time. In addition to these tests the anti-scale devices have been tested in the field at cooling condensers.
Surface diagnostics for scale analysis
Authors: Dunn S. , Impey S. , Kimpton C. , Parsons S.A. , Doyle J. , Jefferson B.
Published: May 2018

Stainless steel, polymethylmethacrylate and polytetrafluoroethylene coupons were analysed for surface topographical and adhesion force characteristics using tapping mode atomic force microscopy and force-distance microscopy techniques. The two polymer materials were surface modified by polishing with silicon carbide papers of known grade. The struvite scaling rate was determined for each coupon and related to the data gained from the surface analysis. The scaling rate correlated well with adhesion force measurements indicating that lower energy materials scale at a lower rate. The techniques outlined in the paper provide a method for the rapid screening of materials in potential scaling applications.
The role of endocrine disrupters in water recycling: risk or mania?
Authors: Nghiem L.D. , McCutcheon J. , Schäfer A.I. , Elimelech M.
Published: May 2018

The widespread occurrence of endocrine disrupting chemicals (EDCs), such as steroid hormones, in secondary wastewater effluents has become a major concern in the water recycling practice. This paper investigates the risk of steroid hormone breakthrough during nanofiltration membrane filtration in water recycling applications. The results indicate a dynamic equilibrium between adsorption and desorption of steroid hormone with regard to the membrane. This equilibrium can be pH dependent and there is a possibility for release of steroid hormones at high pH during membrane cleaning procedures or erratic pH variations. Increase in water recovery can severely increase the hormone breakthrough concentration. The results also indicate a possibility of accumulation of steroid hormones in the NF membrane, followed by subsequent release.
Influence of scale deposition on cathodic-protection performance in desalination plant conditions
Authors: Hodgkiess T. , Najm-Mohammed N.A.
Published: May 2018

This paper describes an investigation into the interrelationships between the performance of an impressed current cathodic protection (CP) system and the deposition of scale compounds in a seawater pipe system. Some experiments were conducted on a laboratory set-up but the emphasis was on tests on a 0.25 m diameter steel pipe fed by seawater flowing to a thermal desalination plant. The experimental approach involved monitoring the CP current as a function of time at various set potentials and correlating this data with evidence from visual inspection of the pipe-wall surfaces and small probe specimens. The influences of control potential and seawater flow rate at temperatures of 25-35°C were studied. Selected scale samples were subjected to examination by scanning electron microscopy and X-ray diffraction. The overall findings are discussed in terms of fundamental scale/CP-operation interactions and aspects relevant to practical operation of CP systems on seawater pipe installations.
Evaluation of wastewater effluents for soil aquifer treatment in South Korea
Authors: Cha W. , Choi H. , Kim J. , Kim I.S.
Published: May 2018

Soil batch and column experiments were performed to characterize the wastewater effluents from seven different wastewater treatment plants in the Jonnam province, South Korea, with the purpose of evaluating the effluents for possible application of a soil aquifer treatment (SAT) in Korea. Batch experiments were conducted to measure the biodegradable dissolved organic carbon (BDOC) while 1 m soil columns, for simulating SAT, were employed to further analyze dissolved organic carbon (DOC) removal. The soils were collected from a river bottom in Jonnam. The BDOC fractions and the residual DOC concentrations for the effluents ranged from 19.3 to 59.9% and from 1.0 to 7.5 mg/L, respectively, depending on the reaction time. Applying the tentative criteria based on the data obtained for the BDOC and residual DOC, three effluents, from Gwangju, Hwasoon, and Jangsung, were found to be the most suitable for SAT applications. It was also concluded that the site characteristics should be also considered with regard to the retention time when evaluating the feasibility of SAT application in a certain region.
Modelling carbon oxidation in pulp mill activated sludge systems: calibration of Activated Sludge Model No 3
Authors: Barañao P.A. , Hall E.R.
Published: May 2018

Activated Sludge Model No 3 (ASM3) was chosen to model an activated sludge system treating effluents from a mechanical pulp and paper mill. The high COD concentration and the high content of readily biodegradable substrates of the wastewater make this model appropriate for this system. ASM3 was calibrated based on batch respirometric tests using fresh wastewater and sludge from the treatment plant, and on analytical measurements of COD, TSS and VSS. The model, developed for municipal wastewater, was found suitable for fitting a variety of respirometric batch tests, performed at different temperatures and food to microorganism ratios (F/M). Therefore, a set of calibrated parameters, as well as the wastewater COD fractions, was estimated for this industrial wastewater. The majority of the calibrated parameters were in the range of those found in the literature.
Common stresses affecting activated sludge health and performance - what the four-assay set can tell us
Authors: Archibald F. , Young F.
Published: May 2018

Previously, we developed a novel biological early warning (BEW) system for directly monitoring the health and performance of activated sludge, the “four-assay set”. In the present work, the four-assay set has been used to measure the effects of four common stresses on activated sludge biomass: high temperature; pH; anoxia; and starvation. The results demonstrate both the utility of the Paprican four-assay set as a biomass-evaluating and BEW tool, and the tolerances of a typical kraft mill activated sludge for these four stresses.
Scenario analysis for reduction of effluent load from an agricultural area by recycling the run-off water
Authors: Shiratani E. , Yoshinaga I. , Feng Y. , Hasebe H.
Published: May 2018

We reviewed rates of nitrogen (N) removal in paddy fields and wetlands. Then we developed a numerical model to simulate N flow in an agricultural paddy field area and analyzed scenarios for recycling the agricultural run-off, including field drainage, from an agricultural area with an irrigation/drainage system. In it, we considered N removal in paddy fields, a regulating reservoir, and canals. The review showed that the rate constant for N removal in paddy fields and wetlands was 0.025 m/d under natural conditions and 0.01 m/d under dark conditions. The scenario analysis of recycling paddy field run-off within the model area indicated that a large amount of the effluent load occurred during the transplanting period and that recycling could reduce the effluent N load. The effluent N load would be equal to the inflowing N load at a 48% recycling rate. In this scenario, paddy fields accounted for most of the reduction in the effluent N load, and the mean removal rates per unit area of paddy field and regulating reservoir were 53.6 g ha-1d-1 and 222.6 g ha-1d-1, respectively.
Evaluation of total phosphorus and total nitrogen methods in pulp mill effluents
Authors: Cook D.L. , Frum N.L.
Published: May 2018

Under the Clean Water Action Plan, the US Environmental Protection Agency is requiring states to establish numeric criteria for phosphorus and nitrogen. In preparation for the development of nutrient criteria NCASI undertook a research project to conduct a comparative study of methods for the determination of total phosphorus and total nitrogen in pulp and paper mill matrices. This paper presents results of a single laboratory method evaluation and comparative study of digestion techniques and analytical methods for the determination of total phosphorus (TP) and total nitrogen (TN) in pulp and paper mill secondary treated effluents. Analytical methods included EPA Methods 365.2 and 365.4 for TP. TN and total kjeldahl nitrogen (TKN) methods included EPA Methods 351.2, 351.4, and 353.2. Examinations of sample preservation and storage stability were conducted. Substitution of mercuric sulfate with copper sulfate during block digestion resulted in higher blank levels and method detection limits. TP measurements using EPA Method 365.4 (autoanalyzer) were found to be accurate with a positive bias as determined using matrix spike experiments. Sample digestion by acidic persulfate oxidation or mercuric sulfate block digestion in conjunction with EPA Method 365.4 yielded low blank levels (averages of 0.01 and 0.02 mg/L, respectively), precision of 2.1 and 2.4% relative standard deviations, respectively, and accuracy expressed as an average recovery (%R) of 117% for both. EPA Method 351.2 (autoanalyzer) was more precise than EPA Method 351.4 (ammonia probe). Accuracy (%R) for EPA Method 351.2 ranged from 81 to 95%, depending on the digestion technique applied, and was 55% when EPA Method 351.4 was utilized. Investigation of a method utilizing basic to acidic persulfate oxidation for the simultaneous determination of TN and TP using only two analytical techniques was found to be effective at concentrations above 1 mg/L in pulp mill effluents.
A comparison of conventional activated sludge and low sludge production strategies for advanced treatment of kraft pulp mill effluent
Authors: Werker A. , Malmqvist Å , Welander T.
Published: May 2018

Parallel laboratory investigations were conducted to examine aspects of two distinct but related bioprocess strategies for low sludge production in the treatment of the same TCF kraft pulp mill effluent. The purpose of this article has been to compare the performance results from these two bench-scale trials with respect to nutrient demands, nutrient discharge, COD removal, and waste sludge characteristics. The LSP (Low Sludge Production) process can be used to significantly reduce sludge yield with excellent sludge characteristics. These sludge characteristics seemed to be related to elevated protozoan grazing pressures. The BAS (Biofilm-Activated Sludge) process achieves similar reduced sludge yields and sludge characteristics while at the same time significantly reducing the nutrient demands and discharge levels. For both LSP and BAS process optimization, the selector nutrient loading is critical to the overall process performance. Selector nutrient requirements are distinct from the overall process nutrient requirements.