bluuebunny/crossref_metadata_2025 huggingface dataset:
Dynamic simulation of chemical industry wastewater treatment plants
Authors: Bury S.J. , Groot C.K. , Huth C. , Hardt N.
Published: May 2018

High variability, stringent effluent permits, and often extreme operating conditions define the practice of wastewater treatment in the chemical industry. This paper reviews the benefits and challenges of applying dynamic simulation to chemical-industry wastewater treatment plants by describing case studies at full-scale wastewater treatment plants (WWTP). The applications range from process troubleshooting to optimization and control. The applications have been valuable and useful in developing a deeper understanding of the plants as integrated systems. However there still remains substantial work to implement the dynamic simulations for daily real-time use by plant engineers and operators. This opportunity to improve plant operations is still largely untapped and will remain so until dynamic state estimation and data reconciliation are incorporated into simulation packages for use in developing the on-line simulations.
Performance of an innovative FWS constructed wetland in Crete, Greece
Authors: Dialynas G. , Kefalakis N. , Dialynas M. , Angelakis A.
Published: May 2018

Pompia is an ancient name of a small community in Messara valley, which is the main agricultural area, in central Crete. The constructed wetland in Pompia is a free water surface (FWS) system, for treating the wastewater of the local community of 1,200 p.e. That wastewater treatment plant (WWTP) is a pilot plant but it is simple, safe, innovative, and environmentally friendly. The WWTP was funded by the Region of Crete. The Eastern Crete Development Organization was responsible for the design, supervision, management, and initial operation. The project was completed in August 1999, and has been under operation since then. The effluent is considered to be equivalent to tertiary treated municipal wastewater, and it will be used to irrigate olive orchards. The general sense for a visitor is that the FWS system operates like a natural marsh and a habitat of birds and wild animals. In addition, very high removal rates for BOD5, COD, TSS, TKN, TP, TC, and FC have been obtained.
Minimisation of costs by using disintegration at a full-scale anaerobic digestion plant
Authors: Winter A.
Published: May 2018

Various half-scale and lab-scale investigations have already shown that the disintegration of excess sludge is a possible pre-treatment to optimise anaerobic digestion. To control these results different methods of disintegration were investigated at a full-scale plant. Two stirred ball mills and a plant for oxidation with ozone were applied.

A positive influence of disintegration on the anaerobic biodegradability can be established with application of a stirred ball mill. Biogas production as well as the degree of degradation were increased by about 20%. Laboratory investigations also validate that disintegration increases the polymer demand and leads to a lower solid content after dewatering. A higher pollution level of process water after dewatering even with ammonia and COD corroborates the results of the anaerobic degradation.

Capital costs for the stirred ball mill, costs for energy, manpower and maintenance can be covered if the specific costs for disposal are high. If the development of costs in future and the current discussion about sludge disposal are taken into account sewage sludge disintegration can be a suitable technique to minimise costs at waste water treatment plants.
Effects of ozone treatment on the biodegradability of sludge from municipal wastewater treatment plants
Authors: Yeom I.T. , Lee K.R. , Lee Y.H. , Ahn K.H. , Lee S.H.
Published: May 2018

The effects of ozone pretreatment on the biodegradability of municipal wastewater sludge were determined. Three types of experiments were conducted: anaerobic digestion, aerobic biodegradation, and denitrification using ozone-treated sludge as a carbon source. For 5 days, ozonated sludge at 0.1 gO3/g-SS showed about 2-3 times greater biodegradation compared to the raw sludge in both aerobic and anaerobic conditions. In anaerobic experiments, biodegradation increased with ozone dosage up to 0.2 gO3/g-SS. Further increase of ozone dosage did not improve the biodegradation. In aerobic condition, about 77% of the ozonated sludge at 0.1 gO3/g-SS could be biodegraded after 15 days and is compared with 36% degradation of the untreated sludge. Most of the biodegradation of the ozonated sludge occurred within 5 days while the raw sludge was biodegraded steadily throughout the experimental period. The biodegradation enhancement of ozonated sludge was confirmed in batch denitrification experiments.
Effects of phosphorus recovery requirements on Swedish sludge management
Authors: Levlin E. , Löwén M. , Stark K. , Hultman B.
Published: May 2018

Expected requirements of phosphorus recovery, restrictions on sludge disposal on landfill, and difficulties in obtaining consensus on sludge use on agricultural land has led to several development works in Sweden to change sludge management methods. Especially sludge fractionation has gained interest including following steps to recover products and separate transfer of toxic substances into a small stream. Commercial systems are offered based on technology by Cambi/KREPRO and BioCon and other companies and many other methods are under development. Iron salts are widely used in Sweden as precipitation agents for phosphorus removal and this technology has some disadvantages for phosphorus recovery compared with the use of biological phosphorus removal. The amount of chemicals needed for a KREPRO or a BioCon system was calculated for a treatment plant which has an addition of iron salt resulting in 1,900 mole Fe per tonne DS. The result was compared with the chemical consumption of recovery systems installed at plants with lower use of iron for precipitation. The chemical consumption in equivalents per tonne DS was found to be 5,000 + 6,000 * (molar ratio iron to phosphorus).
Pre-selection of flocculants by the LUMiFuge separation analyser 114
Authors: Sobisch T. , Lerche D.
Published: May 2018

This paper reports on lab-scale investigations in relation to pre-selection of flocculants for sludge dewatering with decanter centrifuges. Results obtained were compared with CST-measurements and discussed in relation to findings under field conditions. Experiments were carried out with sewage sludges of different origin and characteristics and a number of commercial flocculants. Kinetics of sedimentation and clarification were measured as well as the compression behaviour and shear sensitivity of sludge sediments. To measure flocculant performance stability against intensive shearing, total solids in the sludge cake obtained and dewaterability of the sludge cake during the first 20-50 s of centrifugation were compared. A screening test procedure was developed. Efficient flocculants should produce high residual total solids and good initial compressibility. Lab-scale investigations deliver more reliable results if the dynamic behaviour of the sludge under centrifugal acceleration is also investigated. The separation analyser LUMiFuge 114 can provide results about the compression behaviour of sludges in the range between 10 and 100 s. So far no other method or device is known which can deliver such results.
Evaluation of a four year experience with a fully instrumented anaerobic digestion process
Authors: Steyer J.P. , Bouvier J.C. , Conte T. , Gras P. , Sousbie P.
Published: May 2018

For several years, a 1 m3 fixed bed anaerobic digestion process has been operated for the treatment of distillery vinasses. This reactor has been fully instrumented with the following variables available on-line: pH, temperature, liquid and gas flow rates, gas composition (i.e., CH4, CO2 and H2), concentration of bicarbonate, chemical oxygen demand, total organic carbon, volatile fatty acids and partial and total alkalinity, these last four variables being measured twice by different techniques (i.e., using a TOC analyzer, a titrimetric sensor and an infrared spectrometer). The purpose of this paper is to compare the respective benefits of advanced instrumentation for the monitoring of wastewater treatment processes in general, and for anaerobic digestion in particular. It will also provide some statistical analysis of the time required to operate a fully instrumented wastewater treatment process. It is indeed well admitted in the literature that instrumentation is usually the main limitation step for using closed-loop control. However, it is our opinion that, in the near future, this situation will change. This point is discussed based on our four years practical experience.
Comparison of conventional rule based flow control with control processes based on fuzzy logic in a combined sewer system
Authors: Klepiszewski K. , Schmitt T.G.
Published: May 2018

While conventional rule based, real time flow control of sewer systems is in common use, control systems based on fuzzy logic have been used only rarely, but successfully. The intention of this study is to compare a conventional rule based control of a combined sewer system with a fuzzy logic control by using hydrodynamic simulation. The objective of both control strategies is to reduce the combined sewer overflow volume by an optimization of the utilized storage capacities of four combined sewer overflow tanks. The control systems affect the outflow of four combined sewer overflow tanks depending on the water levels inside the structures. Both systems use an identical rule base.

The developed control systems are tested and optimized for a single storm event which affects heterogeneously hydraulic load conditions and local discharge. Finally the efficiencies of the two different control systems are compared for two more storm events. The results indicate that the conventional rule based control and the fuzzy control similarly reach the objective of the control strategy. In spite of the higher expense to design the fuzzy control system its use provides no advantages in this case.
Metal content and particle size distribution of street sediments and street sweeping waste
Authors: German J. , Svensson G.
Published: May 2018

During recent years the interest in street sweeping as a pollutant control measure has increased. For planning of street sweeping programs and disposal of street sweeping waste there is a need to investigate the composition of street sweeping waste and the effect of street sweeping on the remaining sediments on the street. Particle size distribution and heavy metal concentration has been measured for street sweeping waste, street sediments before sweeping and remaining sediments after sweeping. The results show that the concentrations of heavy metals are a function of particle diameter and proportional to the inverse of the particle diameter, i.e. the highest concentrations are found in finest fractions. Regression equations for metal concentrations as a function of particle diameter are presented. According to Swedish guidelines for environmental quality of contaminated sites, heavy metal concentration in the sweeping waste can not be considered as a serious problem. The largest amount of metals and sediment is found in the sandy fractions (0.125-0.5mm). The street sweeper is more effective in removing coarse sediments than fine. This means that the street sediments after sweeping are finer than the sediments before.
Decentralised urban water reuse: The implications of system scale for cost and pathogen risk
Authors: Fane S.A. , Ashbolt N.J. , White S.B.
Published: May 2018

The non-potable reuse of treated sewage in urban areas provides significant conservation of potable supplies beyond that available through water use efficiency. Effluent reuse is also an inevitable requirement in novel decentralised wastewater systems. At present, urban water reuse, where pursued, usually involves large-scale schemes based on new or existing centralised sewage treatment plants. This is despite the diseconomy of scale inherent in pipe networks that balances economies of scale in sewage treatment and negates any cost advantage for wastewater systems with more than around 1,000 connections. In light of this, the theoretical relationship between effluent reuse system scale and pathogen risks was examined at various effluent qualities. Waterborne disease was seen to be a significant factor when reusing effluent in urban areas and smaller systems were found to pose a lower risk of waterborne infection, all other things being equal. Pathogen risks were then included within an economic analysis of system scale. It was concluded that with the inclusion of pathogen risks as a costed externality, taking a decentralised approach to urban water reuse would be economically advantageous in most cases. This conclusion holds despite an exact evaluation of increased waterborne disease due to effluent reuse remaining problematic.
Onsite wastewater differential treatment system: modeling approach
Authors: Lopez Zavala M.A. , Funamizu N. , Takakuwa T.
Published: May 2018

In this paper, the Onsite Wastewater Differential Treatment System (OWDTS), a new approach for improving the traditional onsite wastewater treatment systems (OWTS), is proposed based on differential management and treatment of household wastewater effluents. Three fractions of household wastewater have been differentiated, reduced-volume blackwater, higher-load graywater and lower-load graywater. Based on this differentiation, different treatment processes required for each fraction are discussed. The procedure adopted for treatment of toilet wastes (reduced-volume blackwater) is shown. In the case of graywater, a sketch of treatment processes is provided. The OWDTS seems to be a new approach with higher potential for improvement of traditional OWTS, dry ecological sanitation, recycling of resources (toilet wastes and water), conservation of water resources, etc. Aerobic biodegradation of toilet wastes by using sawdust as a matrix is an essential treatment process of the OWDTS. Membrane technology seems to be the most effective process to treat higher-load gray water. Natural biodegradation of lower-load gray water by soil bacteria needs to be deeply studied.
OH radical monitoring technologies for AOP advanced oxidation process
Authors: Han S.-K. , Nam S.-N. , Kang J.-W.
Published: May 2018

This study has been conducted to investigate OH radical monitoring technologies for the advanced oxidation process (AOP). OH radicals can be measured directly or indirectly through electron paramagnetic resonance (EPR), hydrogen peroxide method and probe compounds such as pCBA. Among the various AOPs, we focused on the application of EPR technique for •OH monitoring in the ultrasonic irradiation process. EPR method is a valuable tool and has a high sensitivity for radical measuring. Our study was performed with 20 kHz ultrasonic processor in 20 ml DMPO (1 mM) solution. The amount of DMPO-OH adduct with hyperfine constants aN = aH = 1.49 mT and g-value 2.0054, coincided with those of the DMPO-OH adduct depends on the reaction time of the sonication. Also, we have found that at least, •OH was accumulated by 2 × 10−10 M for 10 min sonication, when 60% of the initial amount was destroyed through •OH monitoring using a probe compound. With these results, we could assume that recombination of •OH to form hydrogen peroxide occurs at the interfacial region.
Removal of bromate ion from water using TiO2 and alumina-loaded TiO2 photocatalysts
Authors: Noguchi H. , Nakajima A. , Watanabe T. , Hashimoto K.
Published: May 2018

The effects of pH and the surface charge of photocatalyst on photocatalytic reduction of bromate ions in water were examined by using TiO2 and alumina-loaded TiO2 photocatalysts. The amount of adsorbed bromate ion on TiO2 and the reduction rate of bromate ion by the TiO2 photocatalyst increased with lowering pH. It was suggested that the bromate ion adsorbed predominantly on the positively charged surface sites of TiO2 at lower pH, which thus promotes the rate of reduction. The iso-electric point of the TiO2 photocatalyst was shifted to the higher pH region by loading alumina on the TiO2 surface, which resulted in the increase of the adsorbed amount of bromate on the photocatalyst and the reduction rate of bromate ion by the photocatalyst at neutral pH. It was concluded from these results that the photocatalytic reduction of bromate ion can be promoted by pH control of water or by controlling the surface charge of the photocatalyst by loading alumina without pH control of water.
Inhibition effect of chlorine ion on hydroxyl radical generation in UV-H2O2 process
Authors: Tsuneda S. , Ishihara Y. , Hamachi M. , Hirata A.
Published: May 2018

UV-H2O2 process is widely used as an advanced oxidation process (AOP) for the treatment of chlorine volatile organic compounds (CVOCs) such as dichloromethane (DCM) with strong oxidativity of hydroxyl radical generated from photolysis of H2O2. The result of DCM degradation rate at different initial concentrations in UV-H2O2 processes indicated the inhibition effect of produced chlorine ions on DCM oxidation processes, because the first-order degradation rate constant increased with lower initial concentrations. A spin trapping adduct of hydroxyl radical with 5,5-dimethyl-1-pyrroline-n-oxide (DMPO) was quantified by ESR spectrometer after UV irradiation in the presence of different amounts of chlorine ion, and as a result, the chlorine ion was found to act as a hydroxyl radical scavenger, which resulted in decreasing DCM degradation rate. An UV-H2O2 reactor equipped with ion exchangers for removing chlorine ion achieved higher DCM degradation rate than that without ion exchangers.
Behavior of nuisance mussel, Limnoperna fortunei, in water supply facilities
Authors: Goto Y.
Published: May 2018

Limnoperna fortunei, a species of bivalve of foreign origin, was confirmed to exist in Japan for the first time in 1992. It was found in some facilities of Hanshin Water Supply Authority in 1994. Later, it was found to cause various problems such as clogging of sampling pipes. Following this finding, research was initiated to investigate the possibility of its causing major incidents of bio-fouling such as total blockage of water passage by adhering to the raw water transmission pipe wall in massive numbers. As a result, it was found that Limnoperna fortunei was spawned in summer and grew up to 20 mm in size by the end of a one-year period when it began to die out and became detached immediately. Therefore, it was concluded that no deliberate efforts to remove them are required to avoid major problems
Degradation of biotansformation products of nonylphenol ethoxylates by ozonation and UV/TiO2 treatment
Authors: Ike M. , Asano M. , Belkada F.D. , Tsunoi S. , Tanaka M. , Fujita M.
Published: May 2018

The degradation kinetics of biotransformation products of nonylphenol polyethoxylates (NPEOs), nonylphenol (NP), nonylphenol monoethoxylate (NP1EO) and nonylphenoxy carboxylic acid (NP1EC), by ozonation and UV/TiO2 (ultraviolet photocatalytic degradation in the presence of titanium dioxide suspension as a catalyst) were investigated using lab-scale reactors. The degradation rate of NP by UV/TiO2 was the highest among the tested NPEOs metabolites, while NP1EC showed the lowest degradation rate. In contrast, ozonation was especially effective for the breakdown of NP1EC. NP could be also degraded efficiently by ozonation, however, it was much less effective for NP1EO decomposition. Degradation of NP by both chemical oxidation processes followed first-order kinetics. The degradation curves of NP1EO and NP1EC could be approximately described by first-order kinetics also, although the degradation of NP1EC by ozonation seemed to follow a second-order kinetic.
Removal of pyrene by different microalgal species
Authors: Lei A.P. , Wong Y.S. , Tam N.F.Y.
Published: May 2018

The efficiency of seven microalgal species, namely, Chlamydomonas sp., Chlorella miniata, Chlorella vulgaris, Scenedesmus platydiscus, Scenedesmus quadricauda, Selenastrum capricornutum, and Synechosystis sp. to remove pyrene from solution varied from species to species. According to the 6-hour, 12-hour, and 7-day exposure data, S. capricornutum was the most efficient species in the removal of pyrene, followed by S. platydiscus (a local isolate), and the least effective species was C. vulgaris. For all species, the removal was very rapid in the first 3 to 6 hours of treatment, and no significant difference was found between live and dead cells of C. miniata, C. vulgaris and S. capricornutum, indicating that the initial removal was due to passive physico-chemical biosorption. More than 65% of the pyrene adsorbed was bound on cell wall materials of S. capricornutum, suggesting the major binding sites were on cell walls. The pyrene removal was also dependent on the concentration of algal biomass used, the more the biomass the higher the removal percentages. In addition to biosorption, pyrene was accumulated and transformed inside live cells. In 7-day S. capricornutum culture, pyrene was not detected in either culture medium or algal pellets, and pyrene might have been completely transformed by this species. The degree of bioaccumulation and biotransformation was species specific.
The impact of sea water flushing on biological nitrification-denitrification activated sludge sewage treatment process
Authors: Yu S.M. , Leung W.Y. , Ho K.M. , Greenfield P.F. , Eckenfelder W.W.
Published: May 2018

The process performance of the two largest activated sludge processes in Hong Kong, the Sha Tin and the Tai Po Sewage Treatment Works (STW), deteriorated in the initial period after the introduction of seawater flushing in 1995 and 1996, respectively. High effluent ammonia nitrogen (NH4-N) and total suspended solids (TSS) in excess of the discharge standards resulted from incomplete nitrification and changes in floc characteristics. A desktop study on the inhibitory effects of salinity, particularly on nitrification, was subsequently conducted using the Tai Po STW operating data. To assist the upgrade of the Sha Tin STW a five-month extensive bench-scale investigation on a simple but flexible modified Ludzack-Ettinger configuration with bio-selector was conducted to quantify the inhibitory effects due to the saline concentration. The Sha Tin STW upgrade consists of restoration of its original design capacity (conventional process) of 205,000 m3/day from its currently much reduced capacity as a Bardenpho process. Only the volume of the existing biological process and clarifier is to be utilized. The saline concentration ranges from 3,500 up to 6,500 mg Cl-/L, both daily and seasonally. High and greatly fluctuating saline concentrations have been known to inhibit nitrification. Design consideration should also be given to the peak daily and seasonal TKN loading of up to three times the average. Although the nitrifiers maximum specific growth rate was significantly reduced to a low 0.25 day−1, the inhibition was considered to be tolerable with effluent NH4-N and NO3-N consistently at < 1 and < 6 mg/L. The bio-selector was demonstrated to be efficient in control of sludge foaming and bulking with SVI consistently ≤ 125 mL/g. Results from the IAWQ Model No. 1 and the hydraulic model of the secondary clarifiers allowed overall process capacity maximization. With an anoxic mass fraction of 25-30%, operating sludge age of 9-14 days and SVI ≤ 125 mL/g, both the design requirements and the effluent discharge standards could be met. Without these investigations, an unnecessarily large reaction basin and secondary clarifier volume, and hence capital investment, would have resulted.
Removal of indigenous coliphages and fecal coliforms by a novel sewage treatment system consisting of UASB and DHS units
Authors: Uemura S. , Takahashi K. , Takaishi A. , Machdar I. , Ohashi A. , Harada H.
Published: May 2018

A novel sewage treatment system, which consists of an upflow anaerobic sludge blanket (UASB) pre-treatment unit and the following downflow hanging sponge (DHS) unit for polishing up the UASB effluent, was developed as a cost-effective and easy-maintenance sewage treatment system for developing countries. A long-term experiment with actual sewage was conducted in order to evaluate its treatment efficiency of organic substances, nutrients, and pathogen indicator microorganisms such as total coliphages, F+-specific RNA coliphages (RNA coliphages), and fecal coliforms. The main objective of this paper is to investigate the removal efficiency of those indicator microorganisms by the UASB-DHS combined system. The results obtained from the continuous flow experiment indicated a fairly promising removal of the indicator microorganisms, i.e., the log10 reductions of total coliphages, RNA coliphages, and fecal coliforms (based on sewage and DHS effluent) achieved were 2.01 log, 2.02 log, and 2.57 log, respectively. The UASB-DHS combined system was superior to the conventional activated sludge process in the reduction of fecal coliforms, but in the reductions of total and RNA coliphages, the system showed somewhat less removal efficiency. The vertical reducing patterns of the indicator microorganisms along the DHS reactor were also discussed.
Risk evaluation for pathogenic bacteria and viruses in sewage sludge compost
Authors: Watanabe T. , Sano D. , Omura T.
Published: May 2018

Composting can be regarded as the most available option for recycling of sewage sludge. However, the existence of pathogenic bacteria and viruses in the compost has been scarcely investigated until now. So there is little information on the infectious risk through agricultural activities or gardening in using the compost. In this study, several kinds of composts were investigated for detection of pathogenic bacteria (Salmonella spp. and Escherichia coli O 157) and enteric viruses. It was concluded from the result that these bacteria and viruses could not be detected in 1.0 g-wet of any kinds of composts. Infectious risks through agricultural activities or gardening were evaluated by Monte Carlo simulation in the case that the compost was polluted by Salmonella spp., E. coli O 157:117 and Poliovirus 1. Criteria satisfying the acceptable risk (less than 10−4 per year) for these pathogenic bacteria and virus in the compost were determined from the result of simulations. 1.0 [CFU or PFU/g-wet] was available as the criteria for E. coli O157 and Poliovirus 1 in the compost. On the other hand, the criterion for Salmonella spp. in the compost should be established on a lower concentration than 0.001 CFU/g-wet.
Development of rapid in vitro assay for oxidative liver injury and its application to 230 chemicals
Authors: Kim S.H. , Ichikawa K. , Koshiishi I. , Utsumi H.
Published: May 2018

Water environments are thought to be polluted with thousands of synthetic chemicals and biproducts involving persistent organic pollutants and endocrine disrupters, and their human and ecological impacts are causing serious anxiety. Many bioassays have been undertaken to evaluate the hazardous impacts of toxic chemicals dissolved in water. Reactive Oxygen Species (ROS) are well known to be involved in the toxicity of various chemicals. ROS are mostly generated in liver and cause oxidative damage to DNA, lipids and proteins, resulting in the failure of cellular functions. In order to develop an in vitro bioassay system to estimate ROS induced liver toxicity by chemicals, we investigated the lipid peroxidation, liver cell injury, and genotoxicity using the human hepatocellular carcinoma cell line, Hep-G2 (ATCC HB 8065), and applied it to 230 chemicals.
Dynamic behavior of suspended pollutants and particle size distribution in highway runoff
Authors: Furumai H. , Balmer H. , Boller M.
Published: May 2018

Continuous runoff quality monitoring was conducted for one month at urban highway drainage with an area of 8.4 ha. Dynamic change of suspended solids and heavy metal concentrations were investigated during first flush periods, taking the particle size distribution into consideration. Except for Pb, the concentrations of TSS and heavy metals in runoff were within the range of the EMC reported in recent highway runoff research. Particle-bound heavy metals (Zn, Pb, and Cu) accounted for more significant pollutant loads than soluble fractions. Their content decreased with increasing total SS concentration in runoff samples. The results of particle size distribution (PSD) analysis of runoff samples indicate that high TSS concentration samples contained coarser particles. Based on the PSD results, a stepwise wash-off phenomenon of TSS under varying runoff rate conditions was explained by the different washoff behavior of fine (< 20 mm) and coarser particles.
Characterization of natural organic matter in a shallow eutrophic lake
Authors: Thapa P.B. , Nakajima F. , Furumai H.
Published: May 2018

Natural organic matter (NOM) from five sampling stations of a shallow, eutrophic lake, Lake Kasumigaura was analyzed in four different seasons of a year by several NOM characterization methods including GPC and pyrolysis GC/MS with the objective of elucidating its characteristics as well as studying its temporal and spatial changes. A comparison was also made among the characteristics of NOM from this and two other lakes. The study showed that NOM in Lake Kasumigaura had comparable DOC, UVA260, and THMFP with that of Lake Inbanuma, but much higher than that of Lake Tsukui. Both molecular weight and polydispersities remained similar among those three sources but these values were significantly smaller in comparison with Suwannee River NOM. The similarity index analysis based on pyrochromatograms was useful to evaluate spatial and seasonal changes in NOM characteristics. Distinctive characteristics of NOM at KS1 (station near the mouth of Sakura River) were better explained by the difference in pyro-chromatograms rather than in general water quality. Except for KS1, the change in NOM characteristics in the lake water was found to be more pronounced in different seasons than at different locations.
Potential societal and economic impacts of wastewater nutrient removal and recycling
Authors: Randall C.W.
Published: May 2018

Because adequate nutrient controls were not established when there were past opportunities to do so, nutrient pollution of estuaries and coastal waters has resulted in the impairment of ecosystems and major reductions or collapse of fisheries at numerous sites around the world, resulting in major economical and societal impacts. The root of the problem is that the political policies and processes have permitted municipalities, developers, industries and farmers to expand and operate without paying the full cost of their activities, and this has been done at the expense of those who rely on the productivity and recreational value of our estuarine and coastal waters. Some governments have developed remedial nutrient control programs, but most of them have been under funded and inadequately enforced, resulting in small increments of progress that tend to be lost because of inadequate land use and immigration controls. It is believed that nutrient recovery and controlled reuse can provide a major tool for the control of nutrient pollution and should be widely implemented. Plans are currently being developed to promote widespread use of nutrient recovery and reuse in the Chesapeake Bay region of the USA. An example of phosphorus reuse is presented.
Exergy analysis of nutrient recovery processes
Authors: Hellström D.
Published: May 2018

In an exergy analysis, the actual consumption of resources in physical and chemical processes is calculated. Energy and chemical elements are not consumed in the processes - they are only transformed into other forms with lower quality. The principals of exergy analysis are illustrated by comparing different wastewater treatment systems for nutrient recovery. One system represents an end-of-pipe structure, whereas other systems include source separation of grey water, black water, and urine. The exergy flows analysed in this paper are those related to management and treatment of organic matter and nutrients. The study shows that the total exergy consumption is lowest for the system with source separation of urine and faeces and greatest for the conventional wastewater treatment system complemented by processes for nutrient recovery.
Magnetic separation of iron and heavy metals from water
Authors: Navratil J.D. , Shing Tsair M.T.
Published: May 2018

A magnetic separation device is being developed for removal of iron and heavy metals from water. The device consists of a column of supported magnetite surrounded by a movable permanent magnet. The mineral magnetite, or synthetically prepared iron ferrite (FeO.Fe2O3), is typically supported on various materials to permit adequate water passage through the column. In the presence of an external magnetic field, enhanced capacity was observed in using supported magnetite for removal of actinides and heavy metals from wastewater. The enhanced capacity is primarily due to magnetic filtration of colloidal and nanoscale particles along with some complex and ion exchange sorption mechanisms. This paper will review some previous work on the use of magnetite for wastewater treatment and discuss the development and potential of the magnetic nanoscale filtration/sorption process for water treatment. Recent research results are also presented on preliminary experimental studies using the process with water samples containing iron.
A pesticide runoff model for simulating runoff losses of pesticides from agricultural lands
Authors: Li Y.R. , Huang G.H. , Li Y.F. , Struger J. , Fischer J.D.
Published: May 2018

An integrated modeling system was developed to predict runoff losses of pesticides from agricultural lands. The system is an integration of a mathematical model, a database system, and a geographic information system. Information on soil type, land use, land slope, watershed boundaries, precipitation, pesticide usage, as well as physical and chemical properties of pesticides have been input to a GIS, managed through a database, and used for further modeling studies. The modeling outputs were in turn put into the database, such that runoff patterns along with pesticides losses could be further simulated by using a database management system. The final results could then be visualized through GIS. The developed modeling system was applied to the Kintore Creek Watershed, Ontario, Canada, for simulating losses of atrazine from agricultural lands. A water quality monitoring project was carried out from 1988 to 1992 in the watershed to detect conditions of surface water pollution due to the use of pesticides. The modeling outputs were verified through the monitoring data, demonstrating reasonable prediction accuracy. The result indicated that the model provides an effective means for forecasting pesticide runoff from agriculture lands.
Impact of separate urine collection on wastewater treatment systems
Authors: Wilsenach J. , van Loosdrecht M.
Published: May 2018

Wastewater treatment should not only be concerned with urban hygiene and environmental protection, but development of a sustainable society must also be considered. This implies a minimisation of the energy demand and potential recovery of finite minerals. Urine contains 80% of the nitrogen (N) and 45% of the phosphorus (P) in wastewater. Separate collection and treatment would improve effluent quality and save energy in centralised biological nutrient removal (BNR). BNR processes are not optimal to treat water with very low N concentration resulting from separate urine collection. Relying on nutrient removal through sludge production, methanation of the sludge, subsequent nutrient removal from the digestion effluent results in optimised and more sustainable wastewater treatment. This paper quantitatively evaluates this option and discusses the potential.
Nitrification and autotrophic denitrification of source-separated urine
Authors: Udert K.M. , Fux C. , Münster M. , Larsen T.A. , Siegrist H. , Gujer W.
Published: May 2018

In laboratory experiments, source-separated urine was stabilised with nitrification and denitrified via nitritation and anaerobic ammonium oxidation. The highest total ammonia concentration in the influent was 7,300 gN/m3, the maximum pH 9.2. In a moving bed biofilm reactor (MBBR) with Kaldnes® biofilm carriers, we stabilised urine as a 1:1 ammonium nitrate solution. The maximum nitrification rate was 380 gN/m3/d corresponding to 1.7 gN/m2biofilm/d. Nitrite ammonium solutions were produced in a continuous flow stirred tank reactor (CSTR) with 4.8 days sludge retention time (SRT) at 30°C and in a sequencing batch reactor (SBR) with more than 30 days SRT. Nitrate build-up was negligible in both reactors. Nitritation rates were 780 gN/m3/d in the CSTR and 280 gN/m3/d in the SBR, respectively. However, shortening the cycles would increase nitritation in the SBR. High concentrations of nitrous acid, salts, and presumably hydroxylamine suppressed nitrite oxidation in the nitritation reactors. In all three nitrification reactors, maximally 50% of the influent total ammonia was oxidised without pH control. None of the common inhibition or limitation approaches could explain why ammonia oxidation always stopped at pH values around 6. In a batch experiment, we showed that source-separated urine can be denitrified autotrophically by anammox bacteria.
Optimization of phosphorus precipitation from swine manure slurries to enhance recovery
Authors: Burns R.T. , Moody L.B. , Celen I. , Buchanan J.R.
Published: May 2018

Laboratory experiments were conducted using magnesium chloride (MgCl2·6H2O, 64% solution) to force the precipitation of phosphorus and reduce the concentration of soluble phosphorus (PO43-) in two swine wastes. One of the swine wastes tested contained a high concentration of PO43- (initially ≈1,000 mg/L), and the other swine waste tested contained a low concentration of PO43- (initially ≈230 mg/L). The precipitation reactions were performed to determine the required reaction time, pH, magnesium addition rate and seed material for future precipitate recovery work. For the high and low concentration waste, a 10-minute reaction time at a pH of 8.6 was sufficient to remove 98 and 96% of the PO43- from solution. A molar ratio of Mg2+:PO43- of 1.6:1 was determined to be effective for PO43- removal from both the low and high strength wastes. At a molar ratio of 1.6:1, the PO3- in the high concentration waste was reduced from 590 to 12 mg/L. In the low concentration waste, the PO43- concentration was reduced from 157 to 15 mg/L. Seeding the reaction did not significantly enhance the recovery process.
A new phosphate-selective sorbent for the Rem Nut(r) process. Laboratory investigation and field experience at a medium size wastewater treatment plant
Authors: Petruzzelli D. , De Florio L. , Dell'Erba A. , Liberti L. , Notarnicola M. , Sengupta A.K.
Published: May 2018

P-control technologies for municipal wastewater are essentially based on “destructive” methods, that lead to formation of concentrated solid-phases (sludge), usually disposed-off in controlled landfills. Ion exchange, as a “non-destructive” technology, allows for selective removal and simultaneous recovery of pollutants, which can be recycled to the same and/or related productive lines. In this context, the REM NUT® process removes nutrient species (HPO4=, NH4+, K+) present in biologically oxidised municipal effluents and recovers them in the form of struvites (MgNH4PO4; MgKPO4), premium quality slow release fertilisers. The main limitation to the extensive application of this ion exchange based process is the non-availability of selective exchangers for specific removal of nutrient species. This paper illustrates laboratory investigation and pilot scale development of a so-called “P-driven” modified REM NUT scheme based on a new phosphate-selective sorbent developed at Lehigh University, PA, USA.
Phosphate recovery from sewage sludge in combination with supercritical water oxidation
Authors: Stendahl K. , Jäfverström S.
Published: May 2018

Supercritical Water Oxidation (SCWO) is an innovative and effective destruction method for organics in sewage sludge. The SCWO process leaves a slurry of inorganic ash in a pure water phase free from organic contaminants, which opens possibilities for a simple process to recover components like phosphates from the sewage sludge. In a continuous pilot plant for the SCWO process digested sludge has been treated. The ash has been extracted in lab scale with both caustic and acids in order to recover phosphates. By leaching the ash with caustic, 90% of the phosphorus could be separated as a sodium phosphate solution. By treating the sodium phosphate solution with lime, calcium phosphate was precipitated and caustic recovered and circulated back to the leaching process.
Carbon and nitrogen removal from tannery wastewater with a membrane bioreactor
Authors: Goltara A. , Martinez J. , Mendez R.
Published: May 2018

A 3.5 L Membrane Sequencing Batch Reactor (MSBR) was used for the treatment of a wastewater coming from the beamhouse section of a tannery. The wastewater, produced after the oxidation of sulphide compounds, contained average COD and ammonium concentrations of 550 and 90 mg/L respectively. The system was operated for a period of 150 days, with no sludge removal during the whole period of operation. The biomass concentration inside the reactor varied considerably, with maximum values close to 10 g/L at the end of operation. Low biomass yield values were achieved probably due to the low feed/microorganisms (F/M) ratio. An important accumulation of organic matter in the reactor was noticed, although the COD effluent was not affected due to the permeation through the membrane. The nature of this organic matter is finally discussed. Removal efficiencies close to 100% in ammonium and 90% in COD were achieved and the TN removal efficiency ranged from 60 to 90%.
Nitrogen removal from tannery wastewater by protein recovery
Authors: Kabdaşli I. , Ölmez T. , Tünay O.
Published: May 2018

Nitrogen removal from wastewaters has gained importance in recent years. In this paper protein precipitation and recovery potential of leather tanning industry wastewaters were experimentally evaluated. A protein profile for all sources was prepared. Liming was determined to be the most important protein source. Composite samples were made up to assess the protein precipitation applications. Isoelectric pH precipitation yielded around 50% protein removal between the optimum pH interval of 2.1-3.8. FeCl3 proved to be a very effective means of protein removal providing over 60% efficiency. Polyelectrolyte precipitation did not yield satisfactory results. Magnesium ammonium phosphate precipitation followed by acid precipitation of protein provided 85% ammonia removal in addition to 50% protein removal.
Fouling and cleaning of microfiltration membrane in municipal wastewater reclamation
Authors: Xing C.-H. , Wen X.-H. , Qian Y. , Sun D. , Klose P.S. , Zhang X.Q.
Published: May 2018

This paper presents an investigation on fouling and cleaning of a tubular microfiltration membrane for municipal wastewater reclamation. A bi-level complex model, namely channel clogging and pore plugging, was introduced to elucidate the fouling mechanism. Based on 135 days of microfiltration of activated sludge, a preventive method for channel clogging was reasonably proposed and proven to be effective. Without channel clogging, the operation period was observed a five-fold increase on average, reaching 3-4 weeks. To remove pore plugging, a multi-step chemical cleaning was employed and further optimized in terms of temperature and alkaline concentration. Generally, the chemical cleaning could restore the membrane permeability to higher than 90%.
Waste stabilisation pond developments in New Zealand
Authors: Archer H.E. , Mara D.D.
Published: May 2018

Waste stabilisation ponds have been a popular form of wastewater treatment in New Zealand both for large cities and small communities. Over 100 systems have been constructed ranging in size from over 500 ha to less than 0.1 ha. The largest pond system in New Zealand was at Manukau, Auckland and consisted of four ponds with a total of 530 ha. However, ongoing odour and midge releases and an algae parasite problem plus a requirement to reduce ammonia and total nitrogen in summer, led to the decision to decommission the ponds and allow the area to revert to tidal mudflats. The second largest pond system is at Christchurch and totals 226 ha. In contrast to Manukau, the Christchurch ponds have not caused significant odours and final effluent quality has been good. Christchurch has two parallel trains each with three ponds in series. It is proposed to retain and develop the ponds into a seven cells in series arrangement to reduce short-circuiting.

Odour emissions from the Manukau and Christchurch ponds have been measured by the use of olfactometry. Dispersion of odours has been modelled and the extent of “odour travel” determined on a statistical probability basis using actual meteorological data. It can be demonstrated that residential areas can co-exist with ponds, which are not overloaded, with separation distances of 200 metres.
Waste stabilisation ponds in extreme continental climates: a comparison of design methods from the USA, Canada, northern Europe and the former Soviet Union
Authors: Heaven S. , Lock A.C. , Pak L.N. , Rspaev M.K.
Published: May 2018

The paper presents a brief review of the application of WSPs in extreme climates where ice formation occurs during winter. Design standards and methods are compared and different systems are described. Design equations developed by the US EPA and normative standards from the former Soviet Union are compared in a simple example using typical wastewater and performance characteristics. The results are similar except at low temperatures, where the Soviet method can give pond depths outside the prescribed limits. The paper examines construction and operational aspects of extreme climate WSPs, comparing North American, Northern European and Russian standards. It considers why WSP systems have not been widely adopted in Russia and the NIS, and looks at the advantages these systems may have in countries in economic transition.
A multivariate calibration procedure for UV/VIS spectrometric quantification of organic matter and nitrate in wastewater
Authors: Langergraber G. , Fleischmann N. , Hofstädter F.
Published: May 2018

A submersible UV/VIS spectrometer for in-situ real-time measurements is presented. It utilises the UV/VIS range (200-750 nm) for simultaneous measurement of COD, filtered COD, TSS and nitrate with just a single instrument. A global calibration is provided that is valid for typical municipal wastewater compositions. Usually high correlation coefficients can be achieved using this standard setting. By running a local calibration improvements concerning trueness, precision and long term stability of the results can be achieved. The calibration model is built by means of PLS, various validation procedures and outlier tests to reach both high correlation quality and robustness. This paper describes the UV/VIS spectrometer and the calibration procedure.
Determination of sewer roughness and sediment properties using acoustic techniques
Authors: Horoshenkov K.V. , Ashley R.M. , Blanksby J.
Published: May 2018

Measurements have been carried out to determine the effect of porous sediments in a pipe on the attenuation and spectrum of the airborne acoustic field. The results show that the presence of even a relatively thin sandy layer results in a considerable increase in the acoustic attenuation over the broad frequency range. The measured value of the relative attenuation is in the range of 0.6 dB/m. The effect of the sediment on the acoustic spectrum is the reduction in energy of the propagating modes, which is an easily detectable phenomenon. These results pave the way for the development of the instrumentation for non-invasive characterisation of the parameters of sediments in wastewater systems.