bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimisation of control of river and sewage flows in the Great Culvert, England
Authors: Janssen R.H.A. , Mills S.M.
Published: May 2018

In response to the European Union Urban Waste Water Directive, primary and secondary treatment is being installed at Birkenhead Treatment Works on the Wirral Peninsula in the North West of England. The 3.26 m diameter, 3.5 km long Great Culvert conduit currently conveys both river and sewage flow, and discharges these into the Mersey estuary. To avoid unnecessarily treating river flow, River Birket flow will be diverted directly into the Mersey estuary at the upstream end of the Great Culvert. Sewage flows remaining in the Great Culvert will be pumped to the Birkenhead Treatment Works, and treated before discharge to the Mersey. During extreme storm events, excessive river flows will be released into the Great Culvert and into the Mersey by weirs and penstocks. An innovative approach was taken to investigate, develop, and optimise a control strategy of various pumps, weirs, and penstocks in the Great Culvert, with the aim of minimising unscreened discharges and flooding. By combining hydraulic and dynamic control modelling into one study, implementation and commissioning times were reduced. In addition, by exhaustive testing, it was possible to demonstrate to the Environment Agency that all reasonable measures were being taken to minimise flooding in the upstream catchment and discharges to the Mersey.
Water monitoring system for oil contamination using polymer-coated quartz crystal microbalance chemical sensor
Authors: Ueyama S. , Hijikata K. , Hirotsuji J.
Published: May 2018

A water monitoring system with a new chemical sensor for oil contamination was developed. The sensor had an organic polymer film on a quartz crystal microbalance (QCM). The organic film was a hydrocarbon polymer and had high affinities for the organic compounds of petroleum products such as gasoline, kerosene, diesel oil and fuel oil. The monitoring system was composed of a sampling part, a purging part, a humidity control part and a sensor part. The oil in contaminated river water could be detected whose threshold odour number (TON) was less than three. The detecting time was less than 5 min depending on the oil kindness. This system was tested using artificially contaminated river water with the oils, to be found that the sensitivity was kept steady for longer than 6 months with 400 detections of diesel oil and heavy oil. Moreover, the oil kind could be discriminated with only one sensor device by analyzing the desorption response curves obtained by flowing a clean air on the sensor instead of the purging air.
Phosphorus removal with membrane filtration for surface water treatment
Authors: Dietze A. , Gnirß R. , Wiesmann U.
Published: May 2018

Surface waters are often burdened with inflows of low quality water, so that drinking-water production, swimming or ground water charging must be restricted. To ensure the long-term use of such surface water it is necessary to treat the influents or the water used for ground water charging. The current treatment process for phosphorus and turbidity removal is a process combination called floc filtration. By using this conventional method it is possible to reduce the dissolved ortho-phosphate and the turbidity (particulate phosphorus) as well as the amounts of algae and pathogenic organisms to very low concentrations. The high degree of reduction is only achieved by a relatively high dosage of chemicals. A comparison will be made between this process, which represents the state-of-the-art, and the combination of precipitation/coagulation with micro-/ultrafiltration in dead-end filtration mode.
Surface aeration and a small footprint can be combined
Authors: Janssen P.M.J. , Meinema-Linders K. , Niermans R.P.
Published: May 2018

In densely populated areas new WWTPs will need to be designed on a relatively small area. This paper describes a deep Carrousel© (oxidation ditch) concept resulting in a “small footprint” for the aeration basin combined with an efficient and flexible oxygen input. To enable surface aeration in a deep Carrousel system, the basin was provided with so-called draft tubes, vertical cylinders located underneath aerators, almost extending down to the bottom. A draft tube enables the aerator to draw sludge/water mixture from the bottom of the tank, thereby ensuring proper oxygenation of the tank contents over the entire tank depth. The results of pilot-scale tests for verification of the performance of an aerator equipped with a draft tube are presented.

The full scale WWTP Leidsche Rijn, a compact “wrapped-around” Carrousel-3000 system where the draft tube technology is applied in a 7.5 metre deep basin, is described. Before the plant was put into operation a verification test for the aeration efficiency with clean water was carried out. The test showed that the draft tubes have no negative impact on the aeration efficiency of the surface aerators and justified the chosen design concept.
Respirometry-based on-line model parameter estimation at a full-scale WWTP
Authors: Spanjers H. , Patry G.G. , Keesman K.J.
Published: May 2018

This paper describes part of a project to develop a systematic approach to knowledge extraction from on-line respirometric measurements in support of wastewater treatment plant control and operation. The paper deals with the following issues: (1) test of the implementation of an automatic set-up consisting of a continuous laboratory respirometer integrated in a mobile trailer with sampling and dosing equipment, and data-acquisition and communication system; (2) assessment of activated sludge/sewage characteristics from sludge respirograms by model parameter estimation; (3) comparison of the parameter estimates with regular plant data and information obtained from supplementary wastewater respirograms. The paper describes the equipment and some of its measuring results from a period of one week at a large-scale wastewater treatment plant. The measurements were evaluated in terms of the common activated sludge modelling practice. The automatic set-up allowed reliable measurements during at least one week. The data were used to calibrate two different version of the model, and independent parameter estimates were obtained.
Improved design and optimization of aeration control for WWTPs by dynamic simulation
Authors: Alex J. , Binh To T. , Hartwig P.
Published: May 2018

This paper introduces a model library based on the simulation environment MATLAB/SIMULINK which allows the simulation of the aeration system of an wastewater treatment plant (WWTP). The model library presented covers all parts of an aeration system starting with the compressor set over the common air rail, flow resistances through pipes, controllable valves, aeration membranes and ending last not least with the controllers involved. The main objective of the development of the simulation system is the design, test and the support of the installation of more predictable and efficient control concepts for the aeration system in WWTPs. An example is given to demonstrate the application of the simulation system and to promote a control scheme with a flexible reference value for the pressure at the common air rail based on a most open valve (MOV) concept.
International Report: Sludge management and related legislation
Authors: Leschber R.
Published: May 2018

This report comprises the present sludge management practices with special view to agricultural utilization in the European Union and some accessing countries in eastern Europe in comparison with countries from Asia, the United States of America, South Africa and Australia. Information is given on the respective legislation and on future trends.
Perceptions of sewage sludge
Authors: Tyson J.M.
Published: May 2018

In Europe the agricultural reuse of sewage sludge is controlled by Directive but the combined forces of statutory regulation and “market” regulation have made the task of exploiting the scientifically recognised agricultural reuse benefits of sewage sludge arduous to achieve. The paper examines the factors that have influenced the perception of sewage sludge by the public in the UK and how public perception can be exploited in order to achieve regulatory change.
A new real-time drinking water network mixing model for the control and command centre of the city of Paris
Authors: Montiel F. , Coutelan J. , Nguyen B.
Published: May 2018

The Paris drinking water system has the particularity of being supplied by many different sources: surface water from the Seine and Marne rivers and underground water from sixty-three springs. This diversity of origins of the water and the existence of a gridded network leads the company in charge of the production and the quality of the water in Paris, Sagep, to partly mix the water in the network. Knowing the impact of the mixing on the physical parameters, and consequently on the quality of this mixed water, Sagep had searched for a tool to control the water origins in the network in order to limit extreme changes. A study led Sagep to develop a new kind of real-time water mixing model.
Modelling and estimation of physical parameters in a sludge drying system
Authors: Albino D.S. , Barros P.R. , da Rocha Neto J.S. , van Haandel A.C. , Cavaicanti P.F.
Published: May 2018

In this paper is presented the study of a Sludge Drying System used to kill pathogenic organisms living in sludge. The system is modeled and the physical parameters thermal capacity, thermal resistance and thermal time constant are estimated using conventional estimation methods.
Genetic algorithms for the application of Activated Sludge Model No. 1
Authors: Kim S. , Lee H. , Kim J. , Kim C. , Ko J. , Woo H. , Kim S.
Published: May 2018

The genetic algorithm (GA) has been integrated into the IWA ASM No.1 to calibrate important stoichiometric and kinetic parameters. The evolutionary feature of GA was used to configure the multiple local optima as well as the global optimum. The objective function of optimization was designed to minimize the difference between estimated and measured effluent concentrations at the activated sludge system. Both steady state and dynamic data of the simulation benchmark were used for calibration using denitrification layout. Depending upon the confidence intervals and objective functions, the proposed method provided distributions of parameter space. Field data have been collected and applied to validate calibration capacity of GA. Dynamic calibration was suggested to capture periodic variations of inflow concentrations. Also, in order to verify this proposed method in real wastewater treatment plant, measured data sets for substrate concentrations were obtained from Haeundae wastewater treatment plant and used to estimate parameters in the dynamic system. The simulation results with calibrated parameters matched well with the observed concentrations of effluent COD.
Implementation of a wastewater treatment plant operation support tool based on on-line simulation
Authors: Jumar U. , Tschepetzki R.
Published: May 2018

The operators of modern wastewater treatment plants (WWTPs) are faced with increasing demands. Beyond the requirement to consistently meet discharge limits for pollutant loads, the cost efficiency of plant operation is becoming more and more important. This results in new challenges for automatic control and human control action. On-line simulation opens up interesting perspectives to provide comprehensive process information, serving as a base for optimised operation of WWTPs. This paper describes the development and application of a computer analysis and support tool for the large-scale municipal WWTP of the city of Magdeburg, Germany. It will show that by linking a simulation server to the Distributed Control System (DCS) relevant additional features for plant control arise. A good cost-benefit ratio of the system is achieved by using web techniques for implementing the software.
Measures and costs of integrated river basin management - the Wupper example
Authors: Kolisch G. , Londong J. , Renner J.
Published: May 2018

The implementation of the European Water Framework Directive entails additional costs in the areas of management, monitoring and water quality. As a first estimate, an attempt is made to assess the effects of implementation on the development of costs in a sub-basin, taking the Wupperverband as an example. The work and measures required are presented and the costs are assessed. On this basis, a cost estimate for the maximum time required for the implementation of the WFD is made. This takes into account all the relevant tasks in the area of the association with respect to rivers.
The Millennium Dome “Watercycle” experiment: to evaluate water efficiency and customer perception at a recycling scheme for 6 million visitors
Authors: Hills S. , Birks R. , McKenzie B.
Published: May 2018

Thames Water's “Watercycle” project at the Millennium Dome was one of the largest in-building recycling schemes in Europe, designed to supply up to 500 m3/d of reclaimed water for WC and urinal flushing. It catered for over 6 million visitors in the year 2000. Overall, 55% of the water demand at the Dome was met by reclaimed water. The site was also one of the most comprehensive studies ever carried out of water conservation in a public environment, evaluating a range of water efficient appliances and researching visitor perceptions of reclaimed water.

Within the Dome there were six identical core buildings housing the washrooms, which were equipped with a variety of different water-efficient devices for comparison. Water usage by the different appliances was monitored using a sophisticated metering and telemetry system. The importance of correct installation and maintenance of “high tech” water efficient devices was highlighted during the research programme, as some water wastage occurred due to poor installation. The results prove that metering should complement any large-scale water efficient system, so that any faults with the appliances can be quickly identified. The visitor survey showed very positive attitudes to the use of reclaimed water for non-potable uses.
Dynamic operating rules for water supply reservoirs in La Paz
Authors: Bender M.J. , Hranisavljevic D. , Bernardin R. , Bianchi R.
Published: May 2018

Dynamic operating rules have been applied to the drought-prone Andean water supply reservoirs near La Paz, Bolivia. The water supply reservoirs are not using conventional reservoir operating rule curves. Instead, dynamic operating rules opportunistically supply surplus water for soft demands, and proactively adjust the water supply before a drought causes a water shortage. The conventional approach of forcing water levels to follow a set rule curve is replaced with notions of tradeoffs between long-term reliability and short-term supply opportunities. Operators can customise the dynamic rules based on their tolerance of shortages, and can choose to operate more aggressively during wet periods. In this way, the dynamic rules offer a flexible tool for making short-term decisions while managing medium and long-term performance goals. In the case of La Paz, it is possible to utilise the water sources more efficiently in the short-term without significantly reducing the long-term water supply reliability. The dynamic rules will reduce the severity of future water shortages (if they occur) by 60%, and provide opportunities to increase the firm water supply by up to 8% without affecting the long-term reliability.
Nitrification in reed beds - capacity and potential control methods
Authors: Kayser K. , Kunst S. , Fehr G. , Voermanek H.
Published: May 2018

Vertical-flow reed beds (VFBs) are known to be very effective regarding nitrification. However, a generally accepted design formula for dimensioning reed beds for a controlled nitrification process has still not been found.

Especially for the purpose of nitrification a vertical-flow reed bed (VFB) has been installed following an existing unaerated pond-system. The paper presents the results concerning the limits of the VFB's performance as well as the main factors influencing the nitrification process gained by balancing the conversion rates under different loads. Even under high loads the VFB provides an excellent nitrification performance, which is mainly influenced by the wastewater temperature. The ammonia oxidation rate is about 90% at temperatures over 10°C; at temperatures below 5°C the average nitrification rate is still approximately 50%. The hydraulic load and the TKN load have almost no impact on this efficiency (the maximum load has been: 180 mm/d, 7.1 g TKN/(m2*d)). The redox potenial, which is continuously measured in the effluent of the reed bed, proved to be dependent on the current nitrification performance and the oxygen supply of the VFB, and therefore appears to be a suitable control parameter for the operation of VFBs.
Packed bed columns for high rate nitrogen and carbon removals
Authors: Ong S.L. , Hu J.Y. , Lee L.Y. , Ng W.J. , Song L.F.
Published: May 2018

Two packed bed column (PB) systems, namely anoxic-anoxic and anoxic-oxic were investigated for treatment of wastewater containing high concentrations of nitrogen (N) and COD. The anoxic-anoxic PB system was able to achieve N and COD removal rates of up to 6.70 kg N/m3.d and 26.02 kg COD/m3.d, respectively. The responding removal rates of the anoxic-oxic PB system were 7.41 kg N/m3 and 28.00 kg COD/m3.d, respectively. The N and COD removal efficiencies of anoxic anoxic PB system were in the range of 99.2-100% and 97.2-98.8%, respectively. The corresponding removal efficiencies of anoxic-oxic PB system were 97.5-100% and 98.6-99.4%, respectively. These findings showed that a PB system consisting of anoxic-oxic columns in series has a high capacity to remove nitrogenous and carbonaceous compounds even though the influent to the anoxic stage was oxygenated. Better system stability in terms of denitrification was, however, obtained with the anoxic-anoxic system.
Characterization of microbial community in nitrogen removal process of metallurgic wastewater by PCR-DGGE
Authors: Yoshie S. , Noda N. , Miyano T. , Tsuneda S. , Hirata A. , Inamori Y.
Published: May 2018

The metallurgic wastewater generated from the processes of recovering precious metals from industrial wastes contains high concentrations of nitrogen compounds such as ammonia and nitric acid and of salts such as sodium chloride and sodium sulfate. Biological nitrogen removal from this wastewater was attempted by a circulating bioreactor system equipped with an anoxic packed bed and an aerobic fluidized bed. The anoxic packed bed of this system was found to effectively remove nitrite and nitrate from the wastewater by denitrification at a removal ratio of 97%. As a result of denitrification activity tests at various NaCl concentrations, the sludge obtained from the anoxic packed bed exhibited accumulation of nitrite at 5.0 and 8.4% NaCl concentrations, suggesting that the reduction of nitrite is the key step in the denitrification pathway under hypersaline conditions. The microbial community analysis by denaturing gradient gel electrophoresis (DGGE) of PCR-amplified 16S ribosomal DNA (rDNA) fragments revealed that the community diversity varied in accordance with water temperature, nitrate-loading rate and ionic strength. When particular major DGGE bands were excised, reamplified and directly sequenced, the dominant species in the anoxic packed bed were affiliated with the beta and gamma subclasses of the class Proteobacteria such as Alcaligenes defragrans and Pseudomonas spp., respectively.
Decolorization of reactive bright red K2G dye: electrochemical process catalyzed by manganese mineral
Authors: Liu H.-J. , Qu J.-H.
Published: May 2018

This paper presents the results of the decolorization of azo dye K2G by the electrochemical process catalyzed by manganese mineral. It is proved that the MnOOH(s), main component of the manganese mineral, can catalyze the electrochemical process and enhance the decolorization efficiency. X-ray powder diffraction spectrum shows that the content of MnOOH(s) has not been changed at the end of the reaction. The effects of initial pH value, current density, concentration of electrolyte on the decolorization efficiency of the dye were investigated in detail. The initial pH effect on the decolorization efficiency of K2G dye is found not to be significant. The optimum current density is 0.26A/dm2. In addition, a proposed catalyzing mechanism of manganese mineral is discussed in this paper.
Phosphate removal and recovery by a novel electrolytic process
Authors: Sakakibara Y. , Nakajima H.
Published: May 2018

The possibility of removing and recovering phosphate from wastewater by a novel electrolytic process was investigated experimentally. In the process, ion electrodes are immersed in synthetic wastewater and direct current (DC) is applied to coagulate phosphate on the surface of the anode. Experimental results demonstrated that at electric current densities ranged from 0.001 to 0.1 mA/cm2, phosphate was removed and recovered as phosphate-rich aggregates formed on the anode surface. Decreases in phosphate concentration at bulk liquid were in fairly good agreement with the amounts of phosphate in the aggregates. Moreover, the removal rate of phosphate was increased with increasing electric current. In addition, as heavy metal anions such as Cu2+ deposit on the counter electrode (cathode), it was thought that relatively pure phosphate could be obtained by the present process.
Isolation and examination of copper removing bacteria from activated sludge culture
Authors: Fukushi K. , Babel S. , Xuan H.
Published: May 2018

Experiments were carried out to isolate metal removing bacteria from activated sludge culture and test the metal removal capability of isolated bacteria. Two concentrations of copper solution (CuCl2) used to select the copper-tolerance level of each isolate were 0.05 mM and 2.5 mM. Experimental data showed that isolates could be obtained by using non-selective medium (NSM) in the presence of copper. The isolates were displayed on agar plates with diverse colonial morphological characteristics. A maximum uptake of 81 mg/g dry cell mass was observed at an initial copper concentration of 50 mg/l. The minimum uptake was 9 mg/g dry cell mass. Copper uptake efficiency by isolates from NSM with 0.5 mM CuCl2 was significantly different with those from NSM with 2.5 mM CuCl2.
Characterization of an algae-lytic substance secreted by Bacillus cereus, an indigenous bacterial isolate from Lake Kasumigaura
Authors: Nakamura N. , Nakano K. , Sugiura N. , Matsumura M.
Published: May 2018

In order to develop a practical biological strategy for water bloom-control in Lake Kasumigaura, indigenous algae-lytic bacteria targeting Microcystis spp. (the dominant cyanobacteria), was first carried out. Some basic lytic characteristics of the isolates concerning the biological and physico-chemical factors in actual water environments were then investigated. Fifteen algae-lytic bacteria were successfully isolated using the double layer method. The isolate showing the highest lytic activity was identified as Bacillus cereus based on the 16SrRNA sequence. Extracellular products of B. cereus were found to be responsible for algae-lytic activity. Algae-lytic assay tests using bacterial supernatants pre-treated under several conditions indicated that the majority of the effective algae-lytic substances were either hydrophilis or hydrophobics with a carbon number less than 18, and with molecular weight less than 2000 Da. The algae-lytic activity of the bacterial supernatant was found to be enhanced under alkaline conditions, but it was lost under acidic conditions. This pH specific characteristic is advantageous for application in water bloom environments where the pH is usually in the alkaline region.
Preservation of human cell bioassay device for the on-site evaluation of environmental waters
Authors: Shoji R. , Sakai Y. , Sakoda A. , Suzuki M.
Published: May 2018

We have already developed a novel disposable bioassay device based on the low-density lipoprotein (LDL) uptaking activity of human hepatoblastoma Hep G2 cells in our previous work. However, this device is not readily applicable to evaluate river water toxicity on-site because it cannot be preserved for more than one week. In this work, we developed the method for preservation of the device to enable it to be preserved for at least one month. The device can be supplied to individual environmental sites without any facilities for cell culture. We can evaluate river water toxicity by 2 hours of exposure after thawing. Therefore, this kind of device could be a promising tool for daily water quality management.
Seasonal variations in growth rate of phytoplankton in Hakata Bay, Japan
Authors: Nakashima M. , Lee I.-C. , Kusuda T.
Published: May 2018

Recently, water pollution with high concentrations of organic matter has occurred frequently in Hakata Bay. It is said that a high level of primary production provides much organic matter and affects water quality of the bay, and it is proved by the appearance of phytoplankton throughout the year. In this study, we simulated variations of phytoplankton population with a box-type model using monthly data in a long-term measurement and we analyzed the final growth rate changes of phytoplanktons that explain the conditions for its appearance. Consequently, we found that the final growth rate varies with pattern of half-year periodicity and water temperature and/or ambient nutrient controls the final growth rate to be low every January and July.
Spatial and dynamic simulation for Miyun Reservoir waters in Beijing
Authors: Jia H. , Cheng S.
Published: May 2018

In order to assist the water quality management in Miyun Reservoir, a spatial and dynamic simulation model system was built. In the model system, GIS was integrated with the WASP5 model. The integrated model system was then calibrated and verified in different sets of field data. The result showed that the integrated model system could characterize the Miyun Reservoir waters. Two scenarios were then designed and analyzed with the integrated model system. It was indicated that the water quality would improve if the cage fishery was banned, the algae blooms might occur in Miyun Reservoir if the low water stage ocurred but loads remained unchanged.
Adsorption characteristics of benzene on biosolid adsorbent
Authors: Hung-Lung C. , Chen T.-C. , Tsai M.-C. , Chen Y.-L.
Published: May 2018

This study selected biosolids from a petrochemical wastewater treatment plant as the raw material. The sludge was immersed in 0 to 5 mol l-1 of ZnCl2 solutions and pyrolyzed at different temperatures. When the sludge was pyrolyzed for 30 min at temperatures of 400, 500, 600, and 700°C, the corresponding surface area of the biosolid adsorbent was 46, 401, 921, and 727 m2/g, respectively. Pore size analysis indicated that the mesopore (20 to 500 Å) contributed more than the macropore and micropore in the sludge pyrolytic residue. When the benzene influent concentration was 800 ppmv, the adsorption capacity ranged from 59 to 164 mg/g for different biosolid adsorbents. A larger BET surface area and smaller average pore diameter yielded a larger benzene adsorption capacity.
Treatment of domestic sewage in a combined UASB/RBC system. Process optimization for irrigation purposes
Authors: Tawfik A. , Zeeman G. , Klapwijk A. , Sanders W. , El-Gohary F. , Lettinga G.
Published: May 2018

A Rotating Biological Contactor (RBC) was fed with raw domestic wastewater or anaerobic effluents. The experiments were conducted at increasing operational temperatures viz. 11, 20 and 30°C to assess the potential increase in removal efficiencies for the different COD fractions (CODtotal, CODsuspended, CODcolloidal and CODsoluble), E. coli and in the nitrification rate. The results clearly show that, the RBC at HRT of 2.5 h and OLR of 47 gCOD/m2.d provided a very high residual CODtotal value of 228 mg/l when treating domestic wastewater. This was not the case as compared to the results obtained for the system when operated at the same HRT but at lower OLR's of 27, 20 and 14.5 g COD/m2.d with a UASB effluent at operational temperatures of 11, 20 and 30°C respectively. The residual CODtotal values amounted to 100, 85 and 72 mg/l in the final effluents. Moreover, a high removal of ammonia and low residual values of E. coli was found for the RBC when treating a UASB effluent at operational temperature of 30°C as compared to the situation for treatment of domestic wastewater and UASB effluent at lower temperatures of 11 and 20°C. It can be concluded that an efficient pre-treatment of sewage implies a substantial reduction of OLR applied to the RBC and consequently improves the residual of CODtotal, ammonia and E. coli in the final effluent. Therefore, this study supports using a combined system UASB/RBC for treatment of domestic wastewater for reuse in irrigation.
Coagulation of humic-kaolin-pacl aggregates
Authors: Lin W.W. , Sung S.S. , Lee D.J. , Chen Y.P. , Chen D.S. , Lee S.F.
Published: May 2018

Water treatment residual flocs are fractal-like aggregates made of many initial aggregates. We investigated in this study the coagulation dynamics for the humic-mineral-polyaluminium chloride (PACl) aggregates using small-angle light scattering techniques and the free-settling test. In contrast to reports in the literature, the presence of humic acid did not lead to a loose floc. Not only the time evolution of the coagulation dynamics, but also the final floc characteristics are only mildly affected by the humic acid. However, the strength of the formed floc does decline with humic acid, which leads to a turbid supernatant with high level of organics.
Nutrient removal using anaerobically fermented leachate of food waste in the BNR process
Authors: Lee C.Y. , Shin H.S. , Chae S.R. , Nam S.Y. , Paik B.C.
Published: May 2018

Nutrients removal efficiencies highly depend on the presence of biodegradable organic carbon in the biological nutrient removal (BNR) process but most domestic wastewater in Korea has shown a low C/N ratio and has a small amount of biodegradable COD (chemical oxygen demand). On the other hand, about 11,577 tons of food waste that contains a lot of organic material has been produced in Korea per day. The feasibility and applicability of anaerobically fermented leachate of food waste (AFLFW) as an external carbon source was examined in the laboratory-scale BNR process at different operation conditions with synthetic wastewater and domestic sewage. As the addition of AFLFW increased, the average removal efficiencies of SCOD, T-N, T-P changed from 96%, 60%, and 2% to 90%, 77%, and 67%, respectively. From anoxic nitrate utilization tests, it was observed that once the readily biodegradable COD (especially VFAs) was depleted, the denitrification rate reduced from 8.2 mg NO3-N/g VSS/hr to 0.7 mg NO3-N/g VSS/hr. From the molecular size distribution test, it was concluded that about 60% of soluble COD in effluent, which was considered to originate from AFLFW, had a large molecular size (> 30kDa) that was not used by microorganisms.
Destruction of model organic pollutants in water using ozone, UV and their combination (Part I)
Authors: Teo K.C. , Yang C. , Xie R.J. , Goh N.K. , Chia L.S.
Published: May 2018

The experimental results showed that ozone (O3) oxidation is an effective means to destroy phenolic organic pollutants present in water. High removal efficiencies can be readily achieved for most of the model compounds fortified in aqueous matrices within a reasonable time frame. This study also included the oxidation of phenolic compounds using ozone in combination with ultraviolet (UV) irradiation. The extent of mineralization measured in terms of the losses in total organic carbon is promoted by the joint action of ozone and UV in comparison with using ozone alone.
Conversion of pollutants to fertilisers: ion exchange synthesis of potassium sulphate from acidic mine waters
Authors: Muraviev D.
Published: May 2018

The paper reports the results obtained by the development of ion exchange synthesis of K2SO4 from the natural acidic mine waters (AMW) of Rio Tinto area (Huelva, Spain). The process flowsheet includes several sequential stages permitting production of potassium sulphate and desalinated water along with the recovery of four metals.
Dissolved air flotation clarification of activated sludge and wastewaters from chemical industry
Authors: Jokela P. , Immonen J.
Published: May 2018

Wastewaters from separate chemical factories are treated together in an extended aeration activated sludge plant. The factories produce chemicals for paper industry (e.g. starch), latexes and animal feed. The components of the wastewaters include styrene, tertiary butanol and vinyl acetate. Activated sludge is clarified by sedimentation. During winter time, when the water temperature was 3-12°C, the clarification deteriorated causing carry over of suspended solids containing COD. Enhancement of suspended solids and COD removals was studied in a dissolved air flotation jar test unit. Flotation trials were conducted for activated sludge, sedimentation treated final effluent (tertiary treatment) and separate wastewater fractions. The need for chemicals, flocculation and amount of recycle water were judged according to the achieved removals. Dissolved air flotation was found well suited for the clarification of activated sludge, but not technically and economically feasible for the clarification of the wastewater streams before the activated sludge treatment.
Setting-up a control simulation strategy for a sequencing batch reactor (SBR): application to municipal wastewater
Authors: Casellas M. , Dagot C. , Stelmach S. , Pons M.N. , Baudu M.
Published: May 2018

The use of a simulation model for setting up a control strategy for a sequencing batch reactor necessary for treating municipal wastewater is described. The model used is the ASM no 1 model. The objective of the pollution control treatment is the removal of carbon and nitrogen; the optimisation is concerned with the improvement in the biological removal of nitrogen. After experimental identification of the initialisation variables, the model enables different SBR control scenarios to be tested (time variation for each process) leading to the total elimination of nitrogen. The best simulation was tested in a laboratory reactor. On that scale, it was noted that denitrification is an endogenous process. Lastly, the control strategy was tested on a semi-industrial pilot working in a pollution control plant. Other control scenarios can be devised and tested by simulation, in order to improve the productivity of the reactor.
Isolation of naphthalene-degrading bacteria from tropical marine sediments
Authors: Zhuang W.-Q. , Tay J.-H. , Maszenan A.M. , Tay S.T.-L.
Published: May 2018

Oil pollution is a major environmental concern in many countries, and this has led to a concerted effort in studying the feasibility of using oil-degrading bacteria for bioremediation. Although many oil-degrading bacteria have been isolated from different environments, environmental conditions can impose a selection pressure on the types of bacteria that can reside in a particular environment. This study reports the successful isolation of two indigenous naphthalene-degrading bacteria from oil-contaminated tropical marine sediments by enrichment culture. Strains MN-005 and MN-006 were characterized using an extensive range of biochemical tests. The 16S ribosomal deoxyribonucleic acid (rDNA) sequence analysis was also performed for the two strains. Their naphthalene degradation capabilities were determined using gas chromatography and DAPI counting of bacterial cells. Strains MN-005 and MN-006 are phenotypically and phylogenetically different from each other, and belong to the genera Staphylococcus and Micrococcus, respectively. Strains MN-005 and MN-006 had maximal specific growth rates (μmax) of 0.082 ± 0.008 and 0.30 ± 0.02 per hour, respectively, and half-saturation constants (Ks) of 0.79 ± 0.10 and 2.52 ± 0.32 mg per litre, respectively. These physiological and growth studies are useful in assessing the potential of these indigenous isolates for in situ or ex situ naphthalene pollutant bioremediation in tropical marine environments.
A GIS-based modeling system for petroleum waste management
Authors: Chen Z. , Huang G.H. , Li J.B.
Published: May 2018

With an urgent need for effective management of petroleum-contaminated sites, a GIS-aided simulation (GISSIM) system is presented in this study. The GISSIM contains two components: an advanced 3D numerical model and a geographical information system (GIS), which are integrated within a general framework. The modeling component undertakes simulation for the fate of contaminants in subsurface unsaturated and saturated zones. The GIS component is used in three areas throughout the system development and implementation process: (i) managing spatial and non-spatial databases; (ii) linking inputs, model, and outputs; and (iii) providing an interface between the GISSIM and its users. The developed system is applied to a North American case study. Concentrations of benzene, toluene, and xylenes in groundwater under a petroleum-contaminated site are dynamically simulated. Reasonable outputs have been obtained and presented graphically. They provide quantitative and scientific bases for further assessment of site-contamination impacts and risks, as well as decisions on practical remediation actions.
On-line monitoring equipment for wastewater treatment processes: state of the art
Authors: Vanrolleghem P.A. , Lee D.S.
Published: May 2018

A (non-exhaustive) survey of new and existing technologies for the monitoring of wastewater treatment plants is presented. Emphasis is given to the way these sensors can provide insight in the ongoing (bio-) processes. Three different uses for sensors can be found: for monitoring (operator support), in automatic control systems and as tools for plant auditing/optimization/modelling by consultants. From this, sensors have been classified in two basic types: (i) reliable, simple and low maintenance sensors for day-to-day monitoring and control and (ii) advanced, higher maintenance sensors that are used in auditing, model calibration and optimisation. The paper is organized according to the typical unit processes of biological wastewater treatment systems: anaerobic digestion, activated sludge, nutrient removal and sedimentation. Attention is drawn to a number of practical problems associated with the use of sophisticated sensors in the harsh (dirty) conditions of wastewater treatment processes. The use of autocalibration and built-in sensor checks, cleaning systems and reliable sample preparation units is illustrated. The paper ends with a discussion of the applicability of the different sensors.
Under-performance evaluation and rehabilitation strategy for waste stabilization ponds in Mexico
Authors: Lloyd B.J. , Leitner A.R. , Vorkas C.A. , Guganesharajah R.K.
Published: May 2018

Fourteen high altitude (>2,500 m amsl) small Waste Stabilisation Pond systems (WSPs) commissioned during the last 12 years in the State of Mexico in Mexico, were built to a common 3-stage design. Each system is comprised of 2 parallel series of bio-digesters, anaerobic and facultative ponds. All fourteen WSP systems produce poor quality effluents, and eight studied in more detail did not meet any of the national standards for discharge to rivers or the standards required for reuse. The under-performance of these WSPs is underlined by the anaerobic condition of the upper reaches of the Lerma river which receives the sewage from the towns served by these treatment plants.

Preliminary surveillance diagnostics identified fundamental operational problems in all eight WSP systems located in the upper Lerma catchment. The results of an intensive secondary diagnostic performance evaluation on one system were used to identify the reasons for under-performance. Under-performance was caused by under-design, hydraulic short-circuiting, adverse environmental conditions and poor operation and maintenance. A strategy for improvement of design and operation to meet national standards is presented.
Combined photosynthesis and mechanical aeration for nitrification in dairy waste stabilisation ponds
Authors: Sukias J.P.S. , Craggs R.J. , Tanner C.C. , Davies-Colley R.J. , Nagels J.W.
Published: May 2018

New Zealand has 16,500 dairy farms (avg. 220 cows), with cows kept on pasture throughout the year. During the 9-month dairy season, the cows are milked twice a day (averaging 2.5-3 h per day in the dairy parlour). Urine and faecal wastes deposited in the dairy parlour are washed away with high pressure hoses, using large volumes of water. A common method of treatment is in simple two-pond (anaerobic/facultative) lagoon systems, which remove about 95% of suspended solids and BOD5, but only 75% of total-N prior to discharge. High concentrations of ammoniacal-N in the effluent can cause toxicity to aquatic organisms in receiving waters. Mechanical aeration of the second (facultative) lagoon to promote nitrification improves effluent quality by reducing oxygen demand and potential ammonia toxicity to streamlife. Mechanical aeration however is associated with considerable mixing, which may prevent algae from optimising photosynthesis in the facultative lagoon. A series of experiments was undertaken which tested the efficiency of mechanical aeration and then attempted to combine it with daytime algal oxygen production in order to maximise ammonia conversion to nitrate, while minimising costs to the farmer. An experimental facility was developed by dividing a large facultative lagoon into two, producing a matched pair of lagoons, operated in parallel with influent flow split equally. Over successive dairy seasons, various aeration regimes were compared. Continuous aeration promoted nearly complete nitrification of the ammoniacal-N (99% removal), and effluent BOD was approximately halved. However the continuous mixing reduced algal biomass, and thus daytime algal photosynthesis. Night-only aeration permitted greater algal photosynthesis to occur, as well as halving electrical power consumption. Ammoniacal-N removal reduced to 90% (10 g m-3 remaining in the effluent), while BOD removal was also lower than in the continuously aerated lagoon (59 and 69% respectively). Providing a series of biofilm attachment surfaces for nitrifying bacteria by suspending geotextile material close to the surface in the pond in consistently aerobic water resulted in improved ammoniacal-N removal efficiency (93%) with night aeration, but still lower removal than continuous aeration.
Performance of constructed wetland for highway runoff treatment
Authors: Bulc T. , Sajn Slak A.
Published: May 2018

Highways have a long-term impact on the environment, therefore a sustainable approach to their design is vital. In the spring of 2001 a pilot constructed wetland (CW) system was set up at a section of the northeast-southwest motorway in Slovenia. It was designed for a critical flow of 11.75 l/s for 0.75 ha of catchment area. It consisted of a sedimentation basin covering an area of 36 m2 and a CW of 85 m2. The CW was filled with sand media and planted with reeds. Performance efficiency of the system was evaluated from summer to autumn 2001. Some of the physical and chemical parameters monitored varied noticeably. Removal efficiency was 69% for suspended solids, 97% for settleable solids, 51% for COD, 11% for BOD5 and 80% for Fe. Heavy metals such as Cu, Zn, Cd, Ni and Pb were below limited level at the inflow with reduction efficiency in the system of over 90%. Concentrations of N and P showed a limited level of nutrients for biological processes. Results of the study suggest that CW could be an alternative for highway runoff treatment. Further long-term investigations are needed to provide more data on their proper design.
Hybrid treatment systems - anaerobic ponds and trickling filters in Zimbabwe
Authors: Broome J.M. , Morris P.M. , Nanthambwe J.G.
Published: May 2018

The most economic combination of unit treatment processes for a new sewage treatment works in Zimbabwe was found to be anaerobic ponds followed by trickling filters. The regulations governing irrigation with treated effluent permitted the omission of humus tanks or further treatment. Two stage anaerobic ponds are desludged by gravity through fixed sludge outlet pipework. Sludge is disposed of by irrigation of a Eucalyptus plantation. Novel features of the inlet works and pond outlets are also described. The works has functioned for eight years without major problems, but the assumption that humus tanks or settling ponds were not required may have been mistaken. The sludge removal system has worked well. Without the sludge pipework, it is estimated that desludging of the primary ponds would have been required after two years of operation, but they have now operated successfully for eight years. The combination of anaerobic ponds and trickling filters should be considered where land availability or site conditions make facultative ponds difficult or expensive to construct.
The impact of urban discharges on the health-related microbiological quality of untreated surface water: can catchment management solve the problem?
Authors: Jagals P. , Griesel M.
Published: May 2018

Results showed that surface resource water quality in the study catchment was generally of a poor health-related microbiological water quality. This was due to poor quality discharges received from urban developments in the catchment. The quality results implied that several water uses in the catchment would impact negatively on the health of the users. Current developments in setting Resource Quality Objectives to manage the quality of the resources involved do not provide for the various water uses. The particular Catchment Management Agencies would, therefore, not be in a position to judge the health-related status of their surface water resource quality objectively. To alleviate this problem, tentative water-use classifications as well as microbiological criteria are proposed.
Sedimentation and prefermentation of domestic wastewater in a fixed bed biofilm reactor
Authors: Cuevas-Rodríguez G. , Tejero-Monzón I.
Published: May 2018

This investigation was undertaken with the aim of developing a new wastewater prefermentator reactor in order to increase the percentages of sedimentation, hydrolysis and prefermentation of all the organic matter present in the raw wastewater, using only one unit of pre-treatment. The study was carried out using a pilot fixed bed biofilm reactor of 43.3 L in net volume. HRT of 0.5, 1, 2 and 4 h were applied. The reactor has been operating for 403 days during which it has been fed on raw wastewater from the city of Santander, in Spain. The results showed that it is possible to carry out the sedimentation and prefermentation of the organic matter contained in the raw wastewater in this reactor. The TSS average elimination percentage was higher than 50% during the whole testing period. The highest percentage of TSS retained in the reactor was 70% with a HRT of 4 hours and a flow rate of 0.3 m/h. The maximum CODTotal elimination percentage was 30% for any of the four OL tried. The CODParticulate average solubility was greater than 40%. About 44% of the CODDissolved in the effluent consisted of VFA. The highest concentration of VFA measured in the effluent was 44 mg COD/L, applying a HRT of 1 h. The average acidising was slightly higher than 30%. The acetic, propionic, butyric and valeric acids were the species of VFA detected, the acetic acid being the one present in a larger amount (>50%). The production rate of VFA increases as the HRT decreases.