bluuebunny/crossref_metadata_2025 huggingface dataset:
Agricultural diffuse pollution from fertilisers and pesticides in China
Authors: Li Yong , Zhang Jiabao
Published: May 2018

Although contamination of waterbodies by nitrates and pesticides in rural regions as the main element of agricultural diffuse pollution has been gradually realised by agricultural and environmental scientists, and supported by rapidly growing pollution cases, it is still not considered a high priority environmental problem in China because of a lack of efficient monitoring programs to provide systematic analytical data. This paper brings together evidence in terms of surface water, groundwater and the agricultural ecosystem to show the current situation of water contamination related to excess applications of inorganic fertilisers and pesticides on arable land, research on the above topics, and the importance of understanding and support from both the public and government in association with further studies.
How ‘Green’ Are Aquaculture, Constructed Wetlands and Conventional Wastewater Treatment Systems?
Authors: Brix Hans
Published: May 2018

The term ‘green’ is nowadays widely used (and misused) in connection with many types of technologies. If a technology is ‘green’ it usually means that the technology requires less non-renewable energy sources than other alternatives. However, other parameters need to be considered as well, such as sustainability, recycling potential, treatment capacity and potential, conservation of ecosystems, etc. In this paper the energy requirements and nutrient recycling potential of constructed wetlands and wastewater aquaculture facilities are compared with that of conventional wastewater treatment technologies. The energy requirements of constructed wetlands are very low, but if significant reuse of nutrients is included (aquaculture), the energy requirements increase significantly and usually beyond the energy equivalent of the biomass produced. This is especially true in cold temperate climates where the aquaculture systems need to be housed in heated greenhouses and artificial light must be provided to secure operation throughout the year. In countries where fresh water itself is a limiting resource and where the economic capability may limit the use of artificial fertilisers, the reuse potential of wastewater may be more important. The potential for sustainable cropping of the plant biomass is excellent in tropical wetlands as the plants have a high productivity and a continuous growing season. In order to evaluate in more detail the ‘greenness’ of the different wastewater treatment technologies, the life-cycle approach might be applied. However, because constructed wetlands, besides the water quality improvement function, perform a multitude of other functions such as biodiversity, habitat, climatic, hydrological and public use functions, methodologies need to be developed to evaluate these functions and to weigh them in relation to the water quality issues.
Effects of agricultural activities on water pollution with nitrates and pesticides in the Central Valley of Chile
Authors: Donoso G. , Cancino J. , Magri A.
Published: May 2018

The objectives of this study are, first, to describe the present use of fertilisers between the Regions III and VIII of Chile, identifying the associated environmental impacts and their relationship with the predominant agricultural practices and climatic characteristics. Secondly, to simulate the transport of nitrates and pesticides in a dairy and breeding farm of the Central Valley of Chile, employing EPIC (USDA/ARS) in order to determine the importance of these contamination processes. In the North area of Chile, agricultural production generates soil and groundwater salinization problems due to low average rainfall and the use of highly efficient irrigation practices. In the Central zone, nitrate contamination due to agricultural diffuse pollution is evident; this is especially valid for groundwater contamination with nitrates. The South Central area suffers from eutrophication due to an increase in the nutrient levels in surface water. The simulation indicates that the dairy farm in the Central Valley of Chile has a soil loss of 5.02 tons/ha/year or of 14.67 tons/ha/year, based on MUSS or USLE estimates, respectively. It is important to point out that loss of NO3 and pesticides estimated by MUSS and USLE do not exceed maximum allowable standards.
Diffuse agricultural nitrate pollution of groundwaters in India
Authors: Agrawal G. D. , Lunkad S. K. , Malkhed T.
Published: May 2018

Nitrate pollution of groundwater due to urban waste and industrial effluents usually centres around cities. This study has shown that nitrate levels in groundwater over vast agricultural areas can be correlated with intensive irrigated agriculture, corresponding use of nitrogenous fertilizers and groundwater development, and consequent diffuse agricultural pollution has already endangered the safety of potable groundwater for future generations in both rural and urban areas. Chemical and bacterial treatment of groundwater for nitrate removal relies on advanced technology and is considered costly even in the developed world. In a country like India where economic resources are inadequate, action on the suggested preventive measures may be taken without delay at this stage when alarming trends have been recorded.
The Role of Ciliated Protozoa in Subsurface Flow Wetlands and their Potential as Bioindicators
Authors: Decamp O. , Warren A. , Sanchez R.
Published: May 2018

The role of ciliated protozoa in the root zone method of wastewater treatment was assessed by analyzing ciliate community structure in four experimental subsurface flow wetlands (planted or unplanted in either soil or gravel) and estimating Escherichia coli removal due to ciliate predation. A total of 22 different ciliate taxa were isolated from the four reed beds. The first third of each bed contained a higher abundance and diversity than the final third of the bed. There was a qualitative correlation between physicochemical conditions and ciliate community structure: microaerophilic species dominated the organic-rich and oxygen-poor environment of the unplanted soil bed; aerobic and facultative bacterivorous species dominated the better oxygenated gravel beds; a combination of these two communities was found in the planted soil bed. The average grazing rates of ciliates was around 5 times higher in the planted gravel bed (49 bacteria/ciliate/hour) than in the unplanted soil bed (9.5 bacteria/ciliate/hour). Taking into account the retention time and ciliate abundance, it was calculated that ciliates, by their predatory activities, are capable of removing up to 2.35 × 105 and 0.45 × 105E. coli in the first third of the planted gravel bed and unplanted soil bed, respectively. These results are discussed in relation to variation in E. coli removal kinetics. The potential for using ciliate communities as indicators of conditions within constructed wetlands is also assessed.
Capacity of Constructed Wetlands to Remove Parasite Eggs from Wastewaters in Egypt
Authors: Stott R. , Jenkins T. , Bahgat M. , Shalaby I.
Published: May 2018

The use of Gravel Bed Hydroponic (GBH) constructed wetlands for wastewater treatment and reuse in semi-arid climates has been evaluated in Egypt with respect to the removal of parasite eggs from domestic wastewaters.

Influent and effluent from established 100m GBH reed beds receiving partially treated wastewater, were analysed to establish daily parasite loading rates and removal performance of the system under normal operating conditions (201/min; intermittent 12h on/off flow regime.) The system was then challenged with high numbers of parasite eggs (Ascaris sp., Hymenolepis sp. and Toxocara sp.) equivalent to an influent of 100-500 eggs/1 and a daily loading rate of 1.0-7.2 × 106, representing up to a 110-fold increase over typical mean daily loading rates. Wastewater samples were collected from the inlet, at varying distances along the 100m bed profile, and the outlet. Sampling was also carried out at varying time intervals during the flow regime to determine the spatial and temporal removal of eggs along the bed.

In 100m long planted beds, there was significant removal of all selected parasite eggs with the majority being removed within the first 25m. No eggs were detected in the final effluent. These studies demonstrate that GBH wetlands have a capacity for efficient removal of parasite eggs and thus provide a reliable, low cost technology for treating effluent compliant with health related objectives for the treatment of wastewater intended for agricultural reuse.
Horizontal Subsurface Flow Gravel Bed Constructed Wetland with Phragmites Karka in Central India
Authors: Billore S. K. , Singh N. , Sharma J. K. , Dass P. , Nelson R. M.
Published: May 2018

Treatment performance of a field-scale horizontal subsurface (SF) constructed wetland (CW) was evaluated for removal efficiency of BOD, TSS, NH4-N, NO3-N, TKN and P from municipal wastewater emanating from a small community of residential areas in Ujjain, Central India. The SF wetland had a rectangular size and covered an effective surface area of 41.82 m2 with a water retention capacity of 18 m3. The SF medium was composed of a gravel bed supported below on a layer of puddled local clay and overlaid by a thin synthetic liner. CW was planted initially with locally grown grass, Phragmites karka. Plants placed in this rectangular design at the rate of 3 to 4 plants per m2 increased to 6157 plants within ten months producing a biomass of 121 tonnes ha−1. The influent was pretreated before entering the SF system, through two baffles; a grass covered small ditch, followed by a narrow tunnel of packed biofilmed boulders. Removal rates of TSS (48%), TKN (36%), NH4-N (22%) and NO3-N as zero percent were realised. An earthen channel provided initial pretreatment by a land treatment system. Average treatment performance after five months from this SF system recorded removal efficiencies of 78% for NH4-N, TSS; 58-65% for P, BOD and TKN. Effluent dissolved oxygen levels increased to 34% indicating existence of aerobic conditions in the rooted-gravel bed. The SF system overall results established: (a) very cost-effective treatment technology, (b) SF removal efficiency above 50% for BOD, NH4-N, TKN, and P. This SF system presents a unique design consideration compared with the land-intensive Kickuth standard system design.
Wastewater Treatment by Tropical Plants in Vertical-flow Constructed Wetlands
Authors: Kantawanichkul S. , Pilaila S. , Tanapiyawanich W. , Tikampornpittaya W. , Kamkrua S.
Published: May 2018

A subsurface vertical-flow laboratory scale wetland system was designed to investigate the wastewater treatment efficiency by Vetiveria zizanioides Nash, a common grass in Thailand. Diluted pig farm wastewater was fed intermittently. The removal efficiencies in terms of organic carbon, nitrogen and suspended solids were satisfactory under hydraulic and organic loading rates of 36 mm/d and 55 kgCOD/ha.d, respectively.

A comparison of the performance of the systems with Vetiveria zizanioides Nash and Cyperus flabelliformis Rottb. to treat domestic wastewater was made. It was found that both plants are suitable for wastewater treatment by vertical-flow constructed wetlands in tropical areas under hydraulic and organic loading rates within 121 mm/d and 198 kgCOD/ha.d, respectively.
Design and Hydraulic Performance of a Constructed Wetland Treating Oil Refinery Wastewater
Authors: Simi Anne L. , Mitchell Cynthia A.
Published: May 2018

This paper considers the hydraulics of a wetland constructed by BP Oil for polishing wastewater from their oil refinery at Bulwer Island, Australia. As this open water surface flow (SF) wetland has a novel design to enhance mixing, a tracer study was performed to analyse the hydraulic flow distribution through the wetland. It is a baseline study, following construction, prior to planting. As introduction to the study, details of the wetland design are provided, together with design justification.

The volume of the wetland active zone is estimated as 70% of the total wetland capacity, which compares very favourably with the active volume expected in flat-bottomed ponds. The large amount of dispersion observed along the length of the wetland bed approaches that of a well-mixed system, supporting the claim that this novel bed structure enhances mixing. We expect to at least retain, and possibly improve the degree of mixing by alternating planted shallow zones with unplanted deep zones.

The first stage of experimental work at this wetland involves creating a baseline of hydraulic data on which to build a mass balance model of the wetlands performance. Tracer studies will be repeated on the planted, mature wetland to determine the changes to flow, which might occur in the operating system. Together with wetland performance results, these studies will underpin investigations into the pollutant removal mechanisms at BP Oil's Bulwer Island wetland.
Flow Pattern Analysis of Constructed Wetlands Treating Landfill Leachate
Authors: Rash Jonathan K. , Liehr Sarah K.
Published: May 2018

Three series of tracer studies were performed on three constructed wetlands at the New Hanover County Landfill near Wilmington, North Carolina, USA. One vegetated free water surface wetland (FWS-R), one vegetated subsurface flow wetland (SSF-R), and one unvegetated control subsurface flow wetland (SSF-C) were studied. A conservative tracer, lithium chloride, was used to study the chemical reactor behavior of these wetlands under normal operating conditions. Results indicated that short-circuiting is quite common in SSF wetlands, while FWS wetlands are well-mixed and not as subject to short-circuiting. These results were obtained from and reinforced with tracer measurements at interior points in these wetlands, analysis of residence time distributions from two different formulations, and the construction of residence volume distributions. The short-circuiting in the SSF wetlands can be attributed to the following: (1) Vertical mixing is inhibited by a combination of physical barriers and density gradients caused by rainfall and runoff dilution of the upper layer; and (2) Leachate is drawn from the bottom of the wetland, causing it to further prefer a flow path along the bottom.
Impact of Heavy Metals on Denitrification in Surface Wetland Sediments Receiving Wastewater
Authors: Sakadevan K. , Zheng Huang , Bavor H. J.
Published: May 2018

Denitrification in sediment-water systems is a predominant process in the removal of nitrogen from wetlands and sediments receiving recycled water. In this study the impact of cadmium (Cd), copper (Cu) and zinc (Zn) on denitrification was examined for a wetland sediment receiving recycled water. Results from the study showed that application of 100 mg Cd kg−1 sediment had no effect (P<0.05) on denitrification (161±2.7 mg N kg−1 sediment) compared to the control (162±2.4 mg N kg−1 sediment) which did not receive Cd, Cu or Zn. Addition of 100 mg Cu or Zn kg−1 sediment significantly increased denitrification (170±1.8 and 168±2.7 mg N2O-N kg−1 sediment for Cu and Zn, respectively) compared to the control treatment. Addition of Cd, Cu or Zn at 500 or 1000 mg kg−1 sediment significantly decreased (P<0.05) total denitrification compared to the control and treatments, which received 100 mg Cd, Cu or Zn kg−1 sediment. For a given heavy metal concentration the largest denitrification inhibition occurred with Cd (30.9%) followed by Zn (24.9%) and Cu (18.9%) over a period of seven days. The amount of ammonium in the sediment water increased in all treatments receiving Cd, Cu or Zn and the concentration increased as the concentration of Cd, Cu or Zn increased in the sediment-water environment. For a given heavy metal concentration, the largest increase in ammonium occurred in treatments receiving Cd (31.1±0.9 mg N kg−1 sediment) followed by Zn (24.8±0.5 mg N kg−1 sediment) and Cu (17.0±0.3 mg N kg−1 sediment). Denitrification inhibition was linearly related to the concentration of ammonium in sediment water (r2=0.928). In general, the study showed that the addition of Cd, Cu or Zn inhibited denitrification and increased the concentration of ammonium in the sediment-water environment.
Optimisation of the Hamburg wastewater treatment plants by dynamic simulation
Authors: Ladiges Gösta , Günner Christian , Otterpohl Ralf
Published: May 2018

At present the combined wastewater treatment plants Köhlbrandhöft/Dradenau serve approx. 1.85m PE for the treatment of Hamburg wastewater. It is planned to add a further 250,000 PE and therefore it is necessary to carry out optimisation measures. With the help of an extensive project for dynamic simulation, the necessary comparative tests were carried out.

Various variants for the optimisation were tested and compared on the basis of 14-day and annual hydrographs. The results show clear differences in the performance of the variants. The dynamic simulation was able to provide very useful results on the basis of which decisions have been made on the most suitable measures to be taken in practice.

During work on the project the creation of a project team consisting of representatives from the works (planning and operational staff) and the simulation expert, who cooperated intensively in working on the ideas and concepts, proved invaluable. It meant that wide-ranging possibilities for optimisation were tried out and plausible results achieved.
Components of a model-based operation system for wastewater treatment plants
Authors: Obenaus Frank , Rosenwinkel Karl-Heinz , Alex Jens , Tschepetzki Ralf , Jumar Ulrich
Published: May 2018

This report presents the main components of a system for the model-based control of aerobic biological wastewater treatment plants. The crucial component is a model which is linked to the actual processes via several interfaces and which contains a unit which can immediately follow up the current process state. The simulation calculation of the model is based on data which are yielded by on-line measuring devices. If the sensors should fail at times, there are available a number of alternative concepts, some of which are based on the calculations of artificial neural networks or linear methods.
Modelling of an alternating oxidation ditch system
Authors: Stamou A. , Katsiri A. , Mantziaras I. , Boshnakov K. , Koumanova B. , Stoyanov S.
Published: May 2018

This paper presents a mathematical model for an alternating oxidation ditch system, performing carbon oxidation-nitrification, denitrification and settling. The model consists of 1-dimensional mass balance (convection-dispersion) equations, based on the IAWPRC activated sludge model No 1. The data used for the calibration and the application of the model, are collected from a pilot plant. The present work consists of 3 parts. In the first part a brief description of the pilot plant is made. The second part deals with a short presentation of the basic equations and the boundary conditions of the model. The calibration and application of the model with the corresponding conclusions are contained in the third part. In the calibration, the values of the dispersion coefficient, E, and the correction factors α and β of the equation of the aeration equipment (rotors) have been determined equal to E=170000 m2 day−1, β=0.85 and α=0.3 and 0.825, for the operation of the rotors in the low and high speed, respectively. The application of the model shows that predicted effluent concentration values are in a very good agreement with experiments.
Modeling the actors in water supply systems
Authors: Tillman D. , Larsen T. A. , Pahl-Wostl C. , Gujer W.
Published: May 2018

A methodology is developed to reveal the dynamics of behavior and interactions among actors (stakeholders) in water supply systems and their effect on the technical network and the ecological and socio-economic environment. An agent-based model is under construction which allows to simulate different scenarios of the actors' behavior and to compare the results with observed phenomena (stylized facts) of Swiss cities. First results further clarify the significance of demand trend analysis. We envision the model in a final stage as being helpful to tackle the task of illuminating the diffusive claims, expectations and interactions of the actors involved. Knowledge about these processes is crucial to uncover bottlenecks hindering the sustainable development of our water supply systems into the future.
Water saving potential of domestic water reuse systems using greywater and rainwater in combination
Authors: Dixon A. , Butler D. , Fewkes A.
Published: May 2018

For a sustainable urban future, society must move towards the goal of efficient and appropriate water use. Reuse of domestic greywater and rainwater has a significant role to play in this task. In this study, rainfall time series have been used in conjunction with estimates of domestic water appliance usage generated by the Monte-Carlo simulation technique to predict long term system performance. Model results show that changes in the attributes of household occupancy, roof area, appliance type and storage volume affect the water saving efficiency of a single store reuse system. Considering greywater and rainwater in combination, the greatest rate of increase of efficiency with storage size occurs in the range 0-100 litres. Further analysis of small volume storage and reuse indicates that savings of up to 80% of the WC flush water can be made with less than 50 litres storage. However, the collection of rainwater in addition to greywater in a single store reuse system offers little improvement in water saving efficiency. Small volume domestic water reuse systems lend themselves to application in the urban housing environment and therefore offer potential in the move towards a more sustainable city.
Sustainable water usage systems: models for the sustainable utilization of domestic water in urban areas
Authors: Terpstra P. M. J.
Published: May 2018

Present water usage of our society cannot be considered sustainable; too much water of high quality is taken from the eco-systems and to much polluted water is discharged. Part of this problem is due to domestic water usage. In the past decade a number of technical measures on appliance level have been developed to reduce domestic water consumption and the efficiency of chemicals used has been increased to enable lower dosages. But further reductions are needed. Reuse and/or recycling water within the domestic system could, in theory, lead to further reductions. Models for integration and cascading of domestic water flows that have been developed are discussed. It is shown that water usage systems with various levels of integration and cascading can lead to significant reductions in domestic water consumption and thus lower the environmental impact of domestic water usage.
Textile wastewater reuse in northern Italy (COMO)
Authors: Rozzi A. , Malpei F. , Bonomo L. , Bianchi R.
Published: May 2018

An extensive research programme has been carried out on advanced treatment of secondary effluents discharged by centralized activated sludge treatment plants fed on mixed textile/domestic effluents in order to produce a final effluent suitable for reuse in the textile factories. Activated carbon adsorption or membrane filtration (ranging from microfiltration to reverse osmosis) have been investigated at pilot plant scale in order to determine the most economical and performing advanced treatment. The increase in concentration of refractory pollutants and of salts discharged in the final effluents because of water recycling within the textile processes have been evaluated by relevant mass balances. A techno-economical analysis on the proposed treatment is also presented.
Experiments on membrane filtration of effluent at wastewater treatment plants in the Netherlands
Authors: van der Graaf J. H. J. M. , Kramer J. F. , Pluim J. , de Koning J. , Weijs M.
Published: May 2018

In the Netherlands interest in advanced treatment is increasing now that almost all wastewater treatment plants apply full biological treatment and nutrient removal. Membrane filtration of WWTP-effluent appears to be a very promising method to remove suspended solids and, in addition, bacteria and viruses. Experiments with a pilot unit consisting of a dual media prefilter and a membrane filter, containing capillary membranes with a pore size of 0.01 μm (ultrafiltration) and working in a semi dead-end mode, gave rather promising results. A flux of 90 l/m2.h was achieved after optimizing the cleaning procedures (TMP 0.6 bar, recovery > 90%). Experiments with microfiltration (transverse flow module) based on the cross-flow principle were successful only at high cross flow velocities (flux 100 l/m2.h, TMP 0.5 bar, recovery 80%).

The ultrafiltrate showed an excellent quality with the absence of suspended solids and bacteria. Finally, low costs for energy (NLG 0.02/m3 (1 NLG = 0.5 US$)) and chemicals (NLG 0.01/m3) were calculated. Further optimization will facilitate the applicability of membrane filtration in the near future.
Variability of roof runoff quality
Authors: Förster Jürgen
Published: May 2018

The variability of the pollution of roof runoff was investigated considering a variety of possibly influencing factors. Runoff samples were taken from an experimental roof system that allows the comparison of five different roof materials at urban background conditions, and from house roofs at five different locations in the town of Bayreuth, Germany. It was found that local sources (e.g. PAH from heating systems), dissolution of the roof systems' metal components, and background air pollution are the main sources of runoff pollution. Its variability is extremely high in between different roofs (up to three orders of magnitude) and high within as well as in between single precipitation events. The first flush is often heavily polluted and should be treated in an appropriate way. Roofs with metal surfaces should not be connected to infiltration facilities as concentrations of copper and zinc by far exceed various toxicity threshold values.
Full scale experience with tannery water management: an integrated approach
Authors: Wiegant W. M. , Kalker T. J. J. , Sontakke V. N. , Zwaag R. R.
Published: May 2018

In this article, an overview is given of the proposed and actual activities that are undertaken to reduce the pollution from the approximately 180 tanneries in Kanpur, Uttar Pradesh, India. As a part of an action plan to reduce the pollution of the river Ganga, this project includes in-house measures to reduce the output of chromium by the tanneries, and pre-treatment at the tanneries to reduce the solids content of the wastewater and to facilitate maintenance of the sewer system. A treatment plant consisting of two Upflow Anaerobic Sludge Bed (UASB) reactors, followed by a post-treatment facility, reduces the wastewater pollution by approximately 80% of BOD, COD, and TSS. However, sulphide output is still high, owing to the high sulphate concentrations in the wastewater. The sludge produced during the operations is projected to be used as a fertilizer.
The role of anaerobic digestion of domestic sewage in closing the water and nutrient cycle at community level
Authors: Zeeman G. , Lettinga G.
Published: May 2018

Decentralised sewage treatment is more and more considered to be a sustainable way of waste(water) treatment. Three different options for the on-site treatment of sewage in combination with VFY (Vegetable, Fruit and Yard waste) with anaerobic treatment as a central technique are presented. The collection system and therewith the composition and concentration of the sewage will determine the type of anaerobic technology and the process conditions to be applied. Model calculations are made for determining the HRT to be applied in a UASB system at an obliged SRT at a certain temperature.
Psychrophilic anaerobic treatment of low strength wastewaters
Authors: Rebac Salih , van Lier Jules B. , Lens Piet , Stams Alfons J. M. , Dekkers Freddy , Th. M. Swinkels Koen , Lettinga Gatze
Published: May 2018

Psychrophilic (2 to 20°C) anaerobic treatment of low strength synthetic and malting wastewater was investigated using a single and two module expanded granular sludge bed (EGSB) reactor system. The chemical oxygen demand (COD) removal efficiencies found in the experiments exceeded 90 % in the single module reactor at an organic loading rate up to 12 g COD dm−3 day−1 and a HRT of 1.6 h at 10-12°C ambient temperature using influent concentrations ranging from 500 to 800 mg COD dm−3. When a two module EGSB system was used at the temperature range 10-15°C, soluble COD removal and volatile fatty acids removal of 67-78% and 90-96% were achieved, respectively, and an OLR between 2.8-12.3 kg COD m−3 day−1 and a HRT of 3.5 h. The second module serves mainly as a scavenger of non-degraded volatile fatty acids (VFA) from the first module. The optimal temperatures for substrate conversion of reactor sludge, after it has been exposed to long term psychrophilic conditions, were similar to those of the original mesophilic inoculum. The specific activities of the sludge in the reactor increased in time by a factor 3, indicating enrichment of methanogens and acetogens even at low temperatures. By adapting the process design to the expected prevailing conditions inside the reactor, the loading potentials and overall stability of the anaerobic high-rate process may be distinctly improved under psychrophilic conditions. The results obtained clearly reveal the big potentials of anaerobic wastewater treatment under low ambient (10-12°C) temperature conditions for low strength wastewaters, very likely including domestic sewage.
Assessment of alternative wastewater treatment approaches in guangzhou, China
Authors: Tao Y. X. , Hills P.
Published: May 2018

The city of Guangzhou, in Guangdong Province, China, faces major problems in the development, implementation and application of a comprehensive water pollution control strategy. Since the 1980s, discharges of industrial wastewater and domestic sewage have increased dramatically, resulting in a continuing deterioration in the quality of urban water bodies. The Pearl River, which passes through the city, is now seriously polluted and water quality in many sections fails to attain even the lowest national surface water quality standards. The 19 urban creeks in the city are also badly polluted, and Guangzhou is facing a water shortage due to pollution of its supply sources.

This paper overviews the water pollution problem of Guangzhou. Existing approaches to wastewater treatment are evaluated using an Analytic Hierarchy Process (AHP) and a form of cost-effectiveness analysis. Problems associated with different approaches are explored. Options to improve the effectiveness of wastewater treatment are proposed. The paper seeks to demonstrate that in Guangzhou, the most effective approach to wastewater treatment involves the use of small and medium-scale treatment facilities. This is in contrast to the situation in many other parts of the world where greater emphasis has been placed on the development of large-scale facilities for wastewater collection, transport and treatment.
Sustainability criteria as a tool in the development of new sewage treatment methods
Authors: Mels Adriaan R. , van Nieuwenhuijzen Arjen F. , van der Graaf Jaap H. J. M. , Klapwijk Bram , de Koning Jaap , Rulkens Wim H.
Published: May 2018

In The Netherlands a research project is presently conducted, which has the objective to identify new, more sustainable sewage treatment scenarios which are based on physical-chemical pretreatment. After collecting possible treatment scenarios by means of literature research and contacts with international experts the identified scenarios are evaluated on sustainability and costs. For evaluating the sustainability, the following sustainability criteria (derived from the Life Cycle Assessment methodology) are used: energy balance, final sludge production, effluent quality, the use of chemicals and space requirement (footprint). Within this paper the use of these criteria is illustrated and discussed by means of two example scenarios and a reference scenario. The calculation results for the two example scenario's show that physical-chemical pretreatment leads to energy saving when biological post treatment is applied. Besides, more energy can be generated through sludge digestion, due to an increased sludge production. However, the increased particle removal also leads to an increased final sludge production after digestion which will have to be disposed of and to a relatively high consumption of chemicals.
Assessment of the sustainability of alternatives for the disposal of domestic sanitary waste
Authors: Ashley R. M. , Souter N. , Butler D. , Davies J. , Dunkerley J. , Hendry S.
Published: May 2018

When attempting to assess the relative sustainability of a process or practice, it is important to be able to use measures which are appropriate. Sustainability can be viewed at different levels. At one level for any given process, the closing of cycles in terms of resource use and outputs (products and waste) may be an aspiration, and make that process in itself sustainable. However, the process may be intrinsically unsustainable when considered within a broader context accounting for all of the economic, ecological and socio-political implications. Traditionally sustainable indicators have been used as a measure to assess increasing or decreasing sustainability, following detailed analyses to define what the appropriate indicators should be. A current UK project investigating the options for the most sustainable means of disposal of domestic sanitary wastes requires measures to assist in the evaluation of the options. This paper reviews the use of indicators in the context of the current project and municipal water systems, and illustrates how an integrated approach may be envisaged incorporating economics, life cycle analysis and risk assessment as part of a framework to assist decision makers when deciding whether changes to systems or practices are likely to be more or less sustainable. A major conclusion is that any moves to introduce sustainable systems can only be made in conjunction with the system users - the public, who must be involved in the formulation of any new practices which require a change in lifestyle.
The Drinking Water Taste and Odor Wheel for the Millennium: Beyond Geosmin and 2-Methylisoborneol
Authors: Suffet I. H. (Mel) , Khiari Djanette , Bruchet Auguste
Published: May 2018

The “Taste and Odor Wheel” developed over the last 15 years has been updated to include new compounds identified in the eight classes of odorants, four tastes, and one mouth feel/nose feel category. Over the last 10 years, other types of odors have been identified, in addition to chlorinous and ozonous odors of disinfectants, the earthy compound geosmin, and the musty compound 2-methylisoborneol (2-MIB). Sophisticated instrumental analysis, e.g., gas chromatography/mass spectrometry (GC/MS), and sensory analysis, e.g., flavor-profile analysis (FPA), have been successfully combined with sensory GC to identify various odorants.
Bio-P and non-bio-P bacteria identification by a novel microbial approach
Authors: Bond Philip L. , Keller Jürg , Blackall Linda L.
Published: May 2018

Culturing bacteria from activated sludge with enhanced biological phosphorus removal (EBPR) has strongly implicated Acinetobacter with the process. However, using fluorescent in-situ hybridisation (FISH) probing to analyse microbial populations, we have shown evidence opposing this widespread belief. We describe the phosphorus (P) removing performance and microbial population analyses of sludges obtained in a laboratory scale EBPR reactor. Two sludges with extremely high P removing capabilities were examined, the P content of these sludges was 8.6% (P sludge) and 12.3% (S sludge) of the MLSS. Identification of bacteria using FISH probing indicated both sludges were dominated by microbes from the beta proteobacteria and high mol% G+C Gram positive bacteria. Acinetobacter could make up only a small proportion of the cells in these sludges. Sludge with extremely poor P removal (P content of 1.5%, referred to as T sludge) was then generated by reducing the P in the influent. Bacteria resembling the G-bacteria became abundant in this sludge and these were identified using FISH probing. The anaerobic transformations of the T and P sludges correlated well with that of the non-EBPR and EBPR biological models respectively, indicating that bacteria in the T sludge have the potential to inhibit P removal in EBPR systems.
Bench-Scale Evaluation of Adsorptive Processes for Taste and Odors Control Using Rapid Small-Scale Column Tests and Flavor Profile Analysis
Authors: Crozes G. , Hagstrom J. , Suffet I. H. , Young C.
Published: May 2018

The City of Appleton, Wisconsin operates an 800 l/s Drinking Water Treatment Plant (WTP). Lake Winnebago serves as the source water which experiences algae blooms that are typically accompanied by severe taste and odor (T&O) episodes. Historically, raw water quality in the summer months prevents the full capacity from being achieved despite the use of potassium permanganate, powdered activated carbon (PAC) and granular activated carbon (GAC) filters. Thus, the City proceeded with a study of various treatment processes to mitigate the T&O problems experienced during the summer months. The relatively short duration of T&O episodes and extensive experimental plan necessitated a bench-scale testing for rapid evaluation of various oxidation and adsorptive processes.

This paper presents a review of the effect of carbon type, dosage, contact time, and application point on the performance of PAC in controlling odors. In addition, the effect of GAC type and empty bed contact time (EBCT) on removal of T&O compounds were evaluated using a rapid small scale column test (RSSCT).
Characterisation of the bacterial consortium involved in nitrite oxidation in activated sludge
Authors: Burrell Paul , Keller Jürg , Blackall Linda L.
Published: May 2018

A sequencing batch reactor (SBR) was operated to selectively grow a nitrite oxidising microbial community and was called the nitrite oxidising SBR (NOSBR). The nitrite oxidising characteristics of the reactor biomass were studied as well as the microbial composition. Molecular biological methods of clone libraries were used to evaluate the microorganisms in both the seed sludge and in the NOSBR sludge. We have found that the nitrite oxidation in the NOSBR was due the presence of bacteria from the Nitrospira phylum and not because of the presence of Nitrobacter which were in very low numbers in the NOSBR and not detected in the seed sludge. We hypothesize that the unknown nitrite oxidising bacteria in wastewater treatment plants are a range of species related to Nitrospira moscoviensis. A suite of primers were developed from the clone sequence data and used in a diagnostic polymerase chain reaction to prove the presence of these novel nitrite oxidisers in a range of full scale and laboratory scale activated sludge plants.
Biosynthesis of Bromophenols in Marine Algae
Authors: Flodin C. , Whitfield F. B.
Published: May 2018

The green marine alga Ulva lactuca is known to contain high concentrations of bromophenols. However, the biosynthetic pathways of their formation is not known. This study was aimed at identifying possible precursors of bromophenols. The bromophenol content and bromoperoxidase activity were measured in the alga collected every month from January to August 1997. Bromoperoxidases were extracted and incubated with various possible precursors of bromophenols and brominated reaction products were identified by gas chromatography-mass spectrometry. The results show that U. lactuca contains a bromoperoxidase which can convert phenol, 4-hydroxybenzoic acid and 4-hydroxybenzyl alcohol to bromophenols. L-tyrosine and 4-hydroxybenzaldehyde could not be converted to bromophenols. Bromophenol content and bromoperoxidase activity exhibited a seasonal variation with high productivity in summer and low in winter.
Efficacy of Bank Filtration for the Removal of Fragrance Compounds and Aromatic Hydrocarbons
Authors: Jüttner F.
Published: May 2018

The elimination of fragrance compounds by bank filtration was studied in a suboxic aquifer. Fragrance compounds were the major volatile organic compounds (VOC) in river water (Neckar / SW Germany) and were accompanied by aromatic hydrocarbons. Typical fragrance compounds were menthol, limonene, a-terpineol, 4-tert.-butylcyclohexanol and 4-tert.butylcyclohexanone. Bank filtration reduced the concentrations of these compounds near to or below their detection limit. The reduction of concentrations in the aquifer was primarily found in the first meters from the river. The concentrations of the aromatic hydrocarbons were reduced to nanogram per liter levels.
Evaluation of a Taste and Odor Incident on the Ohio River
Authors: Noblet J. , Schweitzer L. , Ibrahim E. , Stolzenbach K. D. , Zhou L. , Suffet I. H.
Published: May 2018

This study describes a taste and odor event which occurred along the Ohio River during 1989 involving rinse water from a resin manufacturer that contained chemicals which reacted to form 2-ethyl-4-methyl-1,3-dioxolane (2EMD). The events under which the chemical was formed and transported from the resin manufacturing facility to the sewage treatment plan to the Ohio River are described. Taste and odors were detected in water supplies as far as 137 miles downstream from the point of discharge. Due to its hydrophilic nature, 2EMD was not sufficiently removed by the wastewater treatment plant using activated sludge treatment nor by drinking water treatment facilities downstream, even those which utilized granular activated carbon. 2EMD (consisting of cis:trans isomers, stable at a ratio of about 60:40) was the major component of the odor of the drinking water found in samples of the local water distribution system. An FPA panel described the synthesized cis/trans 60:40 isomer ratio of 2-ethyl-4-methyl-1,3-dioxolane as having a medicinal sweet or sickening sweet smell which matched the odor found in the samples from the impacted sites (resin manufacturer and drinking waters downstream).
The Use of Solid Phase Microextraction (SPME) to Monitor for Major Organoleptic Compounds Produced by Chrysophytes in Surface Waters
Authors: Watson Susan B. , Brownlee Brian , Satchwill Trevor , McCauley E.
Published: May 2018

An efficient extraction method is needed to measure trace levels of taste and odour compounds in surface waters. This is usually accomplished by costly and involved analytical procedures. We have developed a simpler alternative, using a commercially available microextraction apparatus (SPME). With this technique we successfully monitored trace levels of some target organoleptics (unsaturated aldehydes e.g. heptadienal, nonadienal, and related compounds) which commonly cause aquatic taste and odour. We identified these compounds in culture material, and analyzed for them during the development of odourous chrysophyte blooms in two ponds. Preliminary work has also found a good recovery of some important off-flavour terpenoids (e.g. geosmin and MIB). SPME is labour and cost efficient, and therefore appealing to water treatment facilities for detection and monitoring. In addition, SPME requires only small sample volumes, and is therefore suitable for culture work.
Identification of a Woody-hay Odor-causing Compound in a Drinking Water Supply
Authors: Young Connie C. , Suffet I. H. (Mel) , Crozes Gil , Bruchet August
Published: May 2018

β-Cyclocitral and geosmin have been identified as the chemicals responsible for causing hay/woody and earthy odors in Lake Winnebago, respectively. Initial identifications of off-flavors were made by the GC-MS with an MS spectral library and sensory-GC analysis and the identifications were confirmed by GC retention time and MS spectral matches to the known standard compounds. A Weber-Fechner plot has been developed for β-cyclocitral and its three odor descriptors, fresh grass, hay/woody, and tobacco-like, which were observed at different concentration ranges.
Nitrogen loss in a nitrifying biofilm system
Authors: Helmer C. , Kunst S. , Juretschko S. , Schmid M.C. , Schleifer K.-H. , Wagner M.
Published: May 2018

In a biological contactor that is part of the biological pretreatment of landfill leachate in Mechernich (Germany) nitrogen elimination of 60% or more was observed under low dissolved oxygen (DO) conditions. Ammonia was converted without accumulation of nitrite and with only little nitrate production. Interestingly, due to limited supply with organic substrate in the system, this observation cannot simply be explained by a combination of conventional autotrophic nitrification and heterotrophic denitrification. In situ hybridization with 16S rRNA-targeted probes revealed the presence of large microcolonies of at least three different types of ammonia-oxidizing bacteria in those biofilm regions where extremely high nitrogen losses occurred. These results were confirmed by comparative sequence analysis of biofilm-derived amoA (encoding the active-site polypeptide of ammonia-monooxygenase) clones for molecular fine-scale analysis of the ammonia-oxidizing population. In batch tests inoculated with biofilm material nitrogen loss occurred without dosage of organic substrate at a DO concentration of 1 mg/l. The simultaneous presence of ammonia and nitrite in the reactor induced the process of complete nitrogen elimination. N2 was identified to be the gaseous end product of the reaction. These results indicate that under low DO concentrations autotrophic ammonia-oxidizers might be the causative agents of the observed nitrogen loss by performing aerobic/anoxic denitrification with nitrite as electron acceptor and ammonia (or perhaps hydroxylamin) as electron donor.
Integrated Wastewater Treatment Plant Performance Evaluation Using Artificial Neural Networks
Authors: Hamoda Mohamed F. , Al-Ghusain Ibrahim A. , Hassan Ahmed H.
Published: May 2018

Proper operation of municipal wastewater treatment plants is important in producing an effluent which meets quality requirements of regulatory agencies and in minimizing detrimental effects on the environment. This paper examined plant dynamics and modeling techniques with emphasis placed on the digital computing technology of Artificial Neural Networks (ANN). A backpropagation model was developed to model the municipal wastewater treatment plant at Ardiya, Kuwait City, Kuwait. Results obtained prove that Neural Networks present a versatile tool in modeling full-scale operational wastewater treatment plants and provide an alternative methodology for predicting the performance of treatment plants. The overall suspended solids (TSS) and organic pollutants (BOD) removal efficiencies achieved at Ardiya plant over a period of 16 months were 94.6 and 97.3 percent, respectively. Plant performance was adequately predicted using the backpropagation ANN model. The correlation coefficients between the predicted and actual effluent data using the best model was 0.72 for TSS compared to 0.74 for BOD. The best ANN structure does not necessarily mean the most number of hidden layers.