bluuebunny/crossref_metadata_2025 huggingface dataset:
Extending thermophilic anaerobic digestion for producing class a biosolids at the greater vancouver regional districts annacis island wastewater treatment plant
Authors: Krugel Steve , Nemeth Leslie , Peddie Craig
Published: May 2018

The Greater Vancouver Regional District (GVRD) is a major regional agency managing wastewater collection and treatment for Vancouver, Canada and surrounding municipalities. As part of their $ 600 million program to upgrade 2 major plants to secondary treatment, the GVRD was faced with the requirement to produce a treated biosolids meeting the equivalent of a U.S. EPA Class A product to assure success of their new biosolids beneficial use program. Various alternatives to achieve a Class A product were evaluated in detail. The GVRD selected a new and innovative process which they termed extended thermophilic anaerobic digestion. The characteristics of this process which help achieve required pathogen kills are the thermophilic operating temperatures and the series operation of reactors, cutting the bleed-through of pathogens observed in conventional complete mix systems. The new thermophilic digesters have been in operation since 1996 and the flow-through vessels required to complete “extended” operation will be complete in late 1998.
Combined anaerobic treatment of wastewaters and sludges
Authors: Jeníček Pavel , Dohányos Michal , Zábranská Jana
Published: May 2018

One of the most recent and progressive reactor principles used in anaerobic wastewater treatment technology is a vertical compartmentalization, which is used in the USSB (Upflow Staged Sludge Bed) reactor. Thanks to its specific design and features the operation of such a reactor can be very flexible. Examples are given showing tested alternatives of operation with combined wastewater and sludge treatment. A high treatment efficiency and a very low specific sludge production was achieved with the operation of a technological system consisting of a USSB reactor and an aerobic biofilm reactor. In the USSB reactor wastewater and surplus sludge treatment can not only be combined but also anaerobic pretreatment and biological denitrification.
Investigations into and optimisation of the performance of sewage detention tanks during storm rainfall events
Authors: Kowalski R. , Reuber J. , Köngeter Jürgen
Published: May 2018

Combined Sewage Detention Tanks (CSDT) are components of combined sewage systems commonly used in Germany. A lack of knowledge of the processes occurring within these structures causes the engineer to apply conceptual approaches in the simulation of pollutant transport. The investigations presented were implemented in an integrated systematic way. Extensive analytical, experimental and numerical studies of steady and transient phenomena taking place in CSDTs were carried out simulating different levels of hydraulic load. The study of the flow field and the simulation of sedimentation and erosion under realistic conditions resulted in proposals for modification and optimisation of the function of CSDTs. A simple way of predicting the cleaning efficiency is presented.
Development and testing of a new design procedure for the control of aesthetic pollutants at combined sewer overflows
Authors: Balmforth D. J. , Blanksby J. R. , Brown C. , Rogerson C.
Published: May 2018

Two research projects identified the need for a new design guide and software to facilitate the design of combined sewer overflows. The purpose of the design guide and software is to enable the selection of the most cost effective arrangement of overflow and screens according to local circumstances. Strategies were developed to minimise the risk of those testing the design guide and software. Tests took place on a number of projects, one of which is the subject of an ongoing pre and post construction appraisal. The experience gained from the test projects is being fed back into the software development.
Determination of the vertical velocity distribution of floatables in CSOs
Authors: Cigana John , Couture Martin , Meunier Charles , Comeau Yves
Published: May 2018

Control of floatables, since April 1994, is one of the nine minimum controls required by the U.S.EPA (United States Environmental Protection Agency) for CSO (Combined Sewer Overflows) control policy compliance. Municipalities must control and intercept floatables at their overflow sites. Efficient interception of these floatables requires prior characterisation. To accomplish this floatables from the Montréal (Canada) region were intercepted during wet weather events. Many characteristics were analysed, but a special emphasis was given to the measurement of the vertical velocity of the floatables. This vertical velocity was measured using a column that could be rotated around its central axis. Results have shown that 80% of the intercepted floatables have a vertical velocity of over 0.07 m/s.
Characterisation and settling of solids in an open, grassed, stormwater sewer network detention basin
Authors: Jacopin Ch. , Bertrand-Krajewski J. L. , Desbordes M.
Published: May 2018

The objective of the study is to develop new operational management practices for detention tanks during rainfall events in order to limit flooding risk and, at the same time, to reduce pollutant discharges by optimising the settling process. This paper presents the results of the characterisation of settled particles in an open stormwater detention basin with grassed banks and bottom, installed on a separate stormwater network. Solids sampled in the bottom of the basin where the settling process is frequent and solids collected in sediment traps have a fine grain-size distribution close to those of suspended solids in stormwater. The distribution is related to the number and the duration of the flooding events. The pollutant loads are significant but the hydrocarbons and heavy metals concentrations are lower than concentrations measured in solids sampled in detention tanks situated on a combined sewer system.
Catchment “greening” using stormwater in Adelaide, South Australia
Authors: Argue John R. , Pezzaniti David
Published: May 2018

The paper reviews the goals of stormwater management adopted in Adelaide and declares a focus on harvesting of stormwater to replace mains water in irrigating areas landscaped with grass, flower beds and shrubs. Four categories of catchments are recognised according to their levels of pollution production - roof runoff and “low”, “medium” and “high” pollution runoff surfaces. Four case study examples of systems involving appropriate treatment trains are described, each one delivering harvested stormwater suitable for irrigation. Two examples are given of large roof areas draining to gravel-filled trenches providing “passive” irrigation to grassed surfaces and two examples of runoff from ground-level surfaces supplying cleansed recharge to small aquifer storage/recovery schemes.
Role of the biotic compartment in the transfer of zinc through the vadose zone - application to an infiltration system
Authors: Hébrard C. , Delolme C.
Published: May 2018

Relatively little is known about the influence of microorganisms which develop in urban stormwater infiltration basins on the transfer of heavy metals, whereas many reports have emphasized their importance in the mechanisms of retention or solubilization of these elements. We therefore examined the transfer of zinc solutions (2-20 ppm) at different pH (4-7) by columns of sterile sand or sand colonized with Pseudomonas putida. The shape of the elution curves shows that the biofilm adsorbed zinc, causing its elution to be retarded. Adsorption seemed to be reversible, except at pH 6 and 7, and non-instantaneous. Consequently, the stormwater infiltration speed may be of considerable importance.
A study of stormwater infiltration system feasibility and design
Authors: Alfakih E. , Barraud S. , Martinelli I.
Published: May 2018

There are numerous reasons, such the saturation of the existing downstream sewer system or its concentrate discharge impact on the receiving water, for using stormwater infiltration systems. However, their feasibility within an urban development project depends on physical soil characteristics and contamination risk, and also on socio-economic considerations. The choice should be based on multiple comparative evaluations. This paper is an overview of feasibility and decision criteria, taking stock of currently available models and approaches.
The cycling of nitrogen in the Danish agricultural sector and the loss to the environment
Authors: Jørgensen L. A.
Published: May 2018

The total nitrogen flow through the Danish agricultural sector can be obtained from surveys conducted using traditional national statistical methods. These surveys are conducted on a regular yearly basis primarily for national economic reasons. However, the same data can be utilised for the description and quantification of important environmental processes. One of these important environmental processes is the emission of nitrogen into the Danish marine area, since nitrogen is the limiting factor for primary production. A large part of the total emission is derived from agriculture. The total loss of nitrogen is calculated from the input/output model as the residual part and this loss is coupled to the different geographical regions in the country. The agricultural sector is regulated through EU and national regulations. These regulations are presented and commented on from an environmental perspective.
Agricultural diffuse pollution in Thailand
Authors: Tonmanee N. , Kanchanakool N.
Published: May 2018

Over the past two decades there have been a number of changes in Thailand, changes in the environment and quality of life for its people, changes in its communities and in the foundations of its economy. Before 1970, Thailand was a rural society in which local communities depended on the natural resources which surrounded them, and the national economy relied on the export of native crops. The sustainable use of resources was a fundamental aspect of rural life, people understood the interrelationships between the different components of their local environment and their activities which were defined by the need to protect their surrounding resources.

Agriculture is the major profession and source of income for the rural poor. Land degradation and soil depletion result in low crop yields and pollution of the environment; soil erosion and landslides are found in Thailand. Nutrient uptake by crops and loss by leaching is much greater than the nutrients applied. Hence soils become less productive and it results in more land requirement for food production. Forest land declines rapidly in hilly watershed areas.

Thailand is located in a tropical region and European countries are located in a temperate region. The climate is completely different, the temperature during summer in some European countries is probably almost the same as winter in Thailand. Not only is the climate in the two regions different, but land use and soil type are different also. These parameters have to be considered when studying the impact of agricultural diffuse pollution on the environment.

Research studies on agricultural diffuse pollution in water resources in Thailand show that nutrient loads and pesticide residues still do not exceed the standard level. However, there was a trend showing the increase of N-NO3 in water resources, in short-term monitoring of nutrients in the east of Thailand between 1988-1990 and 1993-1995. The result showed the increase of N-NO3 from 1.60 ppm to 2.54 ppm in the same watershed and landuse areas. If the use of fertilizers and pesticides in agriculture is increased without due consideration, Thailand will face the same problem as European countries.
Role of Scirpus Lacustris in Bacterial and Nutrient Removal from Wastewater
Authors: Soto F. , García M. , de Luís E. , Bécares E.
Published: May 2018

Experimental microcosms using macrophytes were set up to determine the role of the plants and their rhizosphere in the removal of nutrients and fecal indicators from rural wastewater. Scirpus lacustris was grown in hydroponic culture and in siliceous gravel to compare them with the efficiency of gravel beds without macrophytes. Design parameters for the different experiments were as follows (surface loads in g/m2/d): 1.1-6.4 BOD, 0.8-1.6 VSS, 0.3-3.5 TN, 0.1-0.3 TP; hydraulic load 4-7 cm/d; and retention time 4-8 d. Organic carbon removal was not significantly correlated to the presence of S. lacustris. The removal of phosphorus and nitrogen was enhanced in the presence of plants, even with extremely low C:N ratios. The presence of S. lacustris was responsible for 30% of TN and 20% of TP removal in summer. Probably due to changes in plant activity, removal efficiencies for these nutrients increased 10% from spring to summer. Concerning pathogen removal, efficiencies of gravel beds with macrophytes were significantly higher than those from the other treatments, reaching up to 99.999%.
Combination of a Well Functioning Constructed Wetland with a Pleasing Landscape Design in Nairobi, Kenya
Authors: Nyakang'o J. B. , van Bruggen J. J. A.
Published: May 2018

The constructed wetland consists of a combination of a sub-surface horizontal flow system (VSB) planted with Typha, followed by a series of three pond systems planted with a variety of plants, including ornamental plants. The plant species include Typha, Cyperus latifolius, Cyperus papyrus, Hydrocotyle, Hydrocleis and Pontederia. The wetland is treating wastewater from a restaurant (The Carnivore) and a swimming pool resort with recreational facilities (Splash), both in Nairobi, Kenya.

The wetland is designed to treat wastewater as well as to provide an aesthetically pleasing and environmentally sensitive landscape with ponds and ornamental plants for recreation. The 0.5 ha wetland is designed for 1,200 population equivalents, and has a high treatment efficiencies for BOD5, SS, COD, faecal coliforms, Kj-N, NH4-N and o-PO4 of 98, 85, 96, 99, 90, 92 and 88% removal.

An attempt has been made to determine a mass balance for the system. Most of the nitrogen and phosphorus is deposited in the soil of both the subsurface horizontal flow constructed wetland and the ponds. Some nitrogen is removed by denitrification, only 6% of it is retained by the plants. The sediments play therefore, a major role in the removal of the nutrients. The constructed wetland attracts many birds (128 bird species have been reported) and amphibians. The overall impression of the wetland is that the dual function of beauty and wastewater treatment is achieved.
Support of sewage processing by an online simulation
Authors: Kolisch G. , Londong J. , Haupt M. , Hulsch C.
Published: May 2018

A program surface was created to simulate the effluent behavior of a sewage plant online by coupling the dynamic simulation with the process system. Standard software was used and the activated sludge process was described by the IAWQ activated sludge model no. 1. A method was developed, by which the 13 substance groups of the IAWQ model are calculated on a few online values (Q, BOD-M3, NH4-N) with the use of multivariate regressions. Using the average values from 15 min cycles, a continuously updated inflow file for the simulation of the sewage plant is created. Additional to the online simulation a prediction simulation can be performed, based on the current online-state. This allows projection of the effluent concentration in different inflow situations.
Design of rural water systems using dynamic models
Authors: Lobbrecht A. H.
Published: May 2018

The properties of main water ways and infrastructure of rural water systems are often determined by very general design methods. These methods are based on standards that use only little information of the actual water system. Most design methods applied in the Netherlands are based on land use and soil texture. Standards have been developed on the basis of generalized properties of water systems. Details of the actual layout of the water system and the way in which that system is controlled, are usually not incorporated. Present-day dynamic simulation programs and the computer power currently available enable more detailed modeling and incorporation of location-specific data into models. Such models can be used to design the water system and can include real data. A model-based design method is introduced, in which the actual situation of the water system is taken into consideration as well as the way in which the water system is controlled. Stochastics concerning the operation and availability of controlling infrastructure are included in the method. Models can be evaluated by including real data. In this way the actual safety of the water system, for example during floods, can be determined. Water-quantity design criteria can be incorporated as well as water-quality criteria. Application of the method makes it possible to design safe water systems in which excess capacities are avoided and in which all requirements of interest are met. The method, called the ‘dynamic design procedure’, can result in considerable savings for water authorities when new systems have to be designed or existing designs have to be reconsidered.
Optimal treatment and rational reuse of water in textile industry
Authors: Terras C. , Vandevivere P. , Verstraete W.
Published: May 2018

Because of the increasing water shortage in Flandres (Belgium), it will be necessary to switch over to alternative industrial water supply sources. The reuse of a part of the effluent requires the development and application of advanced water purification treatments in combination with process control. The current technologies under development in the frame of an EU-project are outlined. The latter project covers an integrated process for the provision of recycled water of guaranteed quality with minimum emissions. The whole process is divided into three modules; a sensor protected aerobic stage (SPAS), an anaerobic treatment (ANASORB) and a holistic polishing (HOLIPOL) module. The modules are flexible in application and can be used separately or together. The case of a jeans finishing plant in which a total recycling system at full scale is operated, is discussed.
Potential of closed water systems on dairy farms
Authors: Willers H. C. , Karamanlis X. N. , Schulte D. D.
Published: May 2018

A more sustainable water management on dairy farms is necessary because of rising tap water production costs and exhaustion of groundwater resources in an increasing number of areas. Alternative water sources like rain water collected from roofs and yards and effluents from on-site wastewater treatment should be considered. The objective of this paper is to discuss options for closed water systems on dairy farms. Animal drinking and cleaning of milking equipment are major water demands on dairy farms. In some regions large volumes are needed for grassland irrigation or manure flushing. Treatment of dairy farm wastewater in constructed wetland systems seems to produce good quality effluents. The most plausible options for closed water systems on dairy farms are the collection and use of rain water and treatment and reuse of wastewater for irrigation, manure flushing and animal drinking water. Whether effluents are safe to be used as animal drinking water should be subject to further research.
Source control in urban sanitation and waste management: ten systems with reuse of resources
Authors: Otterpohl Ralf , Albold Andrea , Oldenburg Martin
Published: May 2018

This paper is a follow up of one presented by Otterpohl et al. (1997) in Water Science & Technology. This extension emphasises the responsibility of the professionals in waste- and wastewater management for future development. It shows a lists of 10 technological options for sanitation with source control. The political discussion about future sanitation systems seems to lack input of those working on further development. Even Agenda 21 is a complete failure in this respect - sadly, in a core subject for survival of future generations. The main task of sanitation besides highest hygienic standards is to keep soil fertile.

Sanitation with the mixing up of food and water cycles washes all those substances out to the seas that are extremely harmful there (accumulation) and extremely necessary on the land (depletion of fertility and fossil resources). New integrated sanitation and waste management systems will mostly have to respect different qualities of matter from human settlements: blackwater with biowaste, greywater, stormwater runoff and non-biodegradable waste. Based on this distinction, nine differentiating and one mixing systems with resources management are presented. Some of them require careful examination in selected pilot projects.
A set of indicators for the assessment of temporal variations in the sustainability of sanitary systems
Authors: Lundin M. , Molander S. , Morrison G. M.
Published: May 2018

The sustainability of an urban water system was studied by application of a set of indicators that focuses on environmental issues and the efficiency and performance of the technical system. Temporal variations of indicators reflecting freshwater resources, drinking water, wastewater and by-products, were investigated for the water and wastewater system in Göteborg. Extended time series of precise data were available for quantitative indicators such as water consumption, energy use and discharge loadings. Qualitative indicators such as drinking water quality, sewage sludge quality and ecosystem status were more difficult to assess, a situation complicated by variations in criteria set in different countries. Although large urban water systems are often considered unsustainable, the set of indicators demonstrate that the water and wastewater system in Göteborg has moved towards a more sustainable status; recycling of nutrients to agriculture remains, though, a major concern.
Metabolism of enhanced biological phosphorus removal and non-enhanced biological phosphorus removal sludge with acetate and glucose as carbon source
Authors: Sudiana I. M. , Mino T. , Satoh H. , Nakamura K. , Matsuo T.
Published: May 2018

Four anaerobic-aerobic sequencing batch reactors were operated with either acetate or glucose as the main carbon sources under phosphorus poor or rich conditions. Limited phosphate loading may suppress the development of polyphosphate accumulating organisms (PAOs) leading to establishment of microbial communities without polyphosphate accumulation. These microbial communities were dominated by glycogen accumulating organisms (GAOs). PAO communities were established under the P rich loading conditions. Both PAO and GAO sludges clearly show that acetate absorption was accompanied by glycolysis with subsequent accumulation of PHAs. Glucose was anaerobically converted to PHAs and glycogen. Glycolysis in PHA synthesis was indicated by the presence of a PHA component polymer, 3-hydroxyvalerate (3HV). It is suspected that synthesis of 3HV is via formation of the intermediate metabolite Propionyl-CoA which consumes reducing power and enables microorganisms to maintain intracellular reduction oxidation potential. When glucose was injected, acetate and propionate were detected in the bulk solution suggesting that fermentation may have taken place. Respiratory quinone analyses and fluorescent in situ hybridization with an RNA targeted oligonucleotide probe revealed that there was no significant difference in microbial communities among the sludges tested.
Flavor Profile Analysis and GC/MS Detection of Phenolic Iodinated Disenfection Byproducts in Drinking Water for the USA Space Program
Authors: Dietrich Andrea M. , Mirlohi Susan , DaCosta Willian F. , Dodd Jennifer Peters , Sauer Richard , Homan Mark , Schultz John
Published: May 2018

Reactions of iodine and phenol were investigated to determine which iodophenols were produced and their odor properties. The research was performed in support of the USA space program that applies iodine to disinfect potable water for spacecraft use. Higher concentrations (50 mg/l) and higher iodine:phenol (e.g. 10:1) ratios resulted in the formation of greater iodophenol concentrations and higher substituted iodophenols. The reactions were fast and nearly complete within 1 hour. For pH 5.5 and 8 and all iodine:phenol ratios, formation of monosubstituted compounds indicated that 2-iodophenol was favored over 4-iodophenol. At the intermediate iodine:phenol ratios of 1:1 and 2:1, substantial amounts of the diiophenols formed and persisted for up to 32 days. The diiodophenols were not detected at iodine:phenol ratios of 0.2:1 and 10:1. The compound 2,4,6-triiodophenol was the major product formed at a 10:1 iodine:phenol ratio and the formation of this trisubstituted phenol appeared nearly complete. Odor evaluation indicated that the iodophenols have much lower odor threshold concentrations (OTC) than phenol. The 2- and 4- iodophenol had OTC values of ≅ 1 and 500 μg/l, respectively, with odors described as “medicinal, phenol, chemical”.
A comparison of different concepts of the running-in of nitrification and denitrification in activated sludge plants
Authors: Nowak O. , Kühn V. , Müller V.
Published: May 2018

Two different concepts of the running-in (without inoculation) of activated sludge plants for nitrification and denitrification have been tested on two pilot plants for the extension of a municipal WWTP. During the running-in period, the aeration tank of one pilot plant was fully aerated, whereas the other pilot plant was operated with an anoxic section of 20%. It could be shown that the installation of anoxic zones during the running-in period leads to a higher nitrite peak as compared to complete aeration of the whole volume of the aeration tank. Hence, it is highly recommended to aerate the whole biological reactor, until complete nitrification is achieved. Furthermore, it was found that the activated sludge of the fully aerated pilot plant was not capable of the reduction step of nitrite to gaseous nitrogen. This indicates that for ‘full’ denitrification the heterotrophic biomass has to be adapted to ‘regular’ anoxic conditions at first.
The use of dynamic BNR and two-dimensional clarifier modelling to investigate nitrogen removal at Eastern Treatment Plant, Melbourne, Australia
Authors: Messenger J. R. , Smith J. C. , Tetreault M. J. , Vitasovic C. , Zhou S. , Scott P. , Kozicki M.
Published: May 2018

The use of process and two-dimensional clarifier modelling to investigate the implications of upgrading Melbourne Water's Eastern Treatment Plant to a nitrification/denitrification process is discussed. Results indicate that the existing clarification capacity is sufficient for the increased solids loading arising from operation at a nitrifying sludge age but that the existing diffuser system may need to be replaced in order to achieve the required oxygen transfer rate. The impact of step feeding into unaerated zones to reduce the aeration tank suspended solids concentration and to achieve denitrification is discussed and the installation of baffles to improve the performance of peripheral feed clarifiers is suggested.
Distribution-Generated Taste-and-Odor Phenomena
Authors: Khiari Djanette , Bruchet Auguste , Gittelman Thomas , Matia Lleonard , Barrett Sylvia , Suffet I. H. (Mel) , Hund Ruth
Published: May 2018

The objectives of this study were to investigate various distribution conditions that directly affect the production of tastes and odors, identify the chemical causes, and develop guidelines to help water utilities solve or prevent these types of problems. This paper presents four case studies of taste-and-odor problems generated in distribution systems. Two types of problems will be presented, (1) problems that occur in association with pipe or reservoir lining material leaching into the water and (2) problems that are caused by a continuation of chemical reactions in the water within the distribution system. The sensory method used was flavor profile analysis (FPA) and the chemical methods were closed loop stripping analysis (CLSA) or liquid-liquid extraction (LLE) coupled with gas chromatography/mass spectrometry (GC/MS). Bromophenols and bromodichloroiodomethanes were found to be the cause of the medicinal odors, while alkyl benzenes and naphthalene were found to be associated with the oil-base paint type of odors.
Retrofitting an existing trickling filter plant to BNR standard - Selfs Point, Tasmania's first
Authors: Morgan Scott , Farley Ray , Pearson Rob
Published: May 2018

Hobart City Council has three separate wastewater catchments. Prior to 1997 one catchment discharged untreated sewage to the Derwent River estuary. The State environmental authority required this wastewater to be treated to nutrient removal standard. Following extensive investigations to determine options, Council decided to transfer this wastewater to the existing Selfs Point trickling filter plant. Augmentation of this facility to biological nutrient removal standard was selected to meet the more stringent licence conditions. Council required the new treatment process to utilise current best industry practice, to have proven performance and to make best use of the existing infrastructure, while maintaining cost effectiveness.

This paper discusses the rationale for incorporating trickling filters into the process specification. It also describes the maximal use of previously existing plant, with over 90% incorporated into the design. A significant feature is that the anaerobic digesters have been retained to ensure good biosolids stabilisation.

Selfs Point has shown that retrofitting a trickling filter plant to BNR performance can be very cost effective where existing facilities are in good condition.
Colorimetric Approach to Cyanobacterial Off-Flavor Detection
Authors: Miller Dwight , Conte Eric D. , Shen C. Y. , Perschbacher Peter W.
Published: May 2018

A colorimetric method to quantify methylisoborneol and geosmin in water and fish flesh based on a spot test by Wood and Snoeyink was developed. To test water samples, one liter of filtered water is pumped through a solid phase extraction device and the off-flavor eluted from the device with toluene. The toluene is combined with a 1 percent vanillin in concentrated sulfuric acid and agitated for 30 min to produce the color change. The standard solution is yellow and at increasing concentrations of 2-methylisoborneol or geosmin the color changes from light orange to blood red. Extraction from 1 liter of water results in a sensitivity of 1 ppb. This is suitable for quality control of seafood. For use in measuring action levels (high and low ppt levels for aquaculture and drinking water, respectively), extraction from greater volumes will be required.
Horizontal Distribution of Geosmin in a Reservoir before and after Copper Treatment
Authors: Sklenar K. S. , Horne A. J.
Published: May 2018

Extracellular geosmin, chlorophyll a, and Anabaena circinalis filament density were measured at several stations on the surface of Lake Perris, a 1.62 × 108 m3 (131,450 acre-ft) reservoir in southern California, before and after the reservoir was treated with copper sulfate. Samples were collected from 22 stations within three hours the day before copper was applied by helicopter to the reservoir, which was undergoing an odorous Anabaena bloom. The day after the copper application, 19 stations were sampled over the same short period of time to see how the copper application affected parameter distribution on the reservoir surface. The presence of higher geosmin concentrations in some areas of the lake after copper treatment suggests that additional geosmin was released into the water when Anabaena cells were lysed by the copper.
Factors Affecting the Stability and Behavior of Grassy Odors in Drinking Water
Authors: Khiari Djanette , Young Connie C. , Amah Ginachi , Ye Quanfang , Atasi Khalil , Huddleston Judith , Suffet I. H. (Mel)
Published: May 2018

The presence of grassy-type odors in drinking water has frequently been determined by flavor-profile analysis (FPA). Previous work (Khiari et al., 1995) has identified cis-3-hexen-1-ol and cis-3-hexenyl acetate as the causes of these odors in laboratory experiments. Both chemicals possess very similar characteristics; however, cis-3-hexenyl acetate has a much lower odor threshold concentration (OTC) than its corresponding alcohol. In this study, both chemicals were identified by both sensory and chemical analyses separately or in combination in natural and treated waters. It was also found that the sensory and chemical characteristics of samples with grassy odors have a tendency to change upon storage and shipment. Hydrolysis was determined to be a major controlling mechanism for the degradation of cis-3-hexenyl acetate and the formation of cis-3-hexen-1-ol in aqueous solution. The kinetics of the hydrolysis of cis-3-hexenyl acetate to cis-3-hexen-1-ol was evaluated in bench-scale experiments. These studies showed the concentration of cis-3-hexen-1-ol and cis-3-hexenyl acetate to be strongly pH-dependent. This study shows that preservation by refrigeration and adjustment of pH to 4.6 were important steps to be taken when quantitation of the compounds is needed. However, the samples should be analyzed as quickly as possible.
Fate of Conventional/Priority Organic Pollutants Associated with Wastewater Reuse in Soil Irrigation in Kuwait
Authors: Al-Muzaini Saleh , Ghosn Ahmad A.
Published: May 2018

Soil contamination from conventional/priority organic pollutants associated the reuse of wastewater for agricultural irrigation in selected sites in Kuwait is assessed in this paper using a laboratory pilot plant designed for this purpose.

The permeated wastewaters included industrial and tertiary treated wastewaters from different industrial and wastewater treatment plants in Kuwait. Tab (potable) water will be also used as a reference base.

The investigated soil sites covered representative agricultural areas in Kuwait including Al-Wafra, Al-Abdally and Sulaibiya agricultural sites. The soil characteristics in these sites are presented.

The preliminary results of pilot plant tests for Abdally area soils are discussed herein and related conclusions and remarks are outlined.
Modeling biochemically driven mineral precipitation in anaerobic biofilms
Authors: Cooke A. J. , Rowe R. K. , Rittmann B. E. , Fleming I. R.
Published: May 2018

A numerical model links the build-up of mineral precipitate (primarily CaCO3) and the anaerobic activity of biofilms, which occur in granular material permeated with leachate from a municipal solid waste landfill. The model represents the porous-media flow system as a collection of elements in which each element acts as a separate, fixed-film reactor. The model represents biofilm growth for microorganisms carrying out acetogenesis of propionate and methanogenesis of acetate. It also directly links substrate utilization to mineral precipitation and accounts for the accumulation of inert biomass on the porous media at any time or position along the length of the column. Thus, the model describes the ecological interactions among fermenters, methanogens, inert biomass, and mineral precipitate. Although substrate utilization by the active microorganisms drives the entire system, mineral precipitate becomes a dominant component in the biofilm.
Modeling cometabolic biodegradation of organic compounds in biofilms
Authors: Champagne Pascale , Parker Wayne J. , Van Geel P.
Published: May 2018

A dynamic model that describes the biodegradation of secondary substrates through oxygenase reactions in biofilms has been developed. The model incorporates intracellular reducing power, in the form of NADH, as a link between the rate of utilization of primary substrates and the biodegradation of secondary substrates. The reaction kinetics were integrated into a diffusive biofilm model with internal and external mass transfer limitations and then combined into a continuous flow reactor model. Preliminary evaluation of the model has demonstrated that mass transfer limitations substantively reduced the removal of the secondary substrate as compared to a suspended growth reactor with an equivalent mass of biomass. A sensitivity analysis revealed that model predictions of the removal of secondary substrate were highly sensitive to the parameters describing the availability of reducing power and to the compound-specific biodegradation kinetic parameters.
Application of biofiltration in the crude oil processing industry
Authors: Sekoulov I. , Brinke-Seiferth S.
Published: May 2018

For the purification of industrial waste water from the crude oil processing industry, a multiple stage treatment plant is recommended. Biofiltration takes place as a secondary treatment stage. Under plug-flow conditions residual compounds can be treated efficiently with a reduced power requirement. Specialized microorganisms, utilizing compounds which are not readily biodegradable, are immobilized on burned clay. Usually toxic peaks do not inhibit the microorganisms in the biofilm. This depends on the short retention time of the water in fixed bed systems and on the characteristic of the biofilm. Dissolved, colloidal or particulate non-biodegradable substances will be adsorbed on the biofilm and can be removed by backwashing the reactor. A description of the treatment plants at BP-oiltech Hamburg and Shell Refinery Hamburg is given. The design of the fixed film reactors is discussed.
Particle size analysis for improved sedimentation and filtration in waste water treatment
Authors: Tiehm A. , Herwig V. , Neis U.
Published: May 2018

Size distributions of particle mass, chemical oxygen demand (COD) and phosphorus at four municipal waste water treatment plants were investigated by fractionation of samples through 0.1-8.0 μm polycarbonate filters and 32-125 μm sieves, respectively. Particle size analysis of primary and secondary effluents at each plant showed significantly different size distribution functions. These distribution functions remained constant with respect to time under dry weather conditions so they can be considered as characteristic patterns for each sample location. Advanced treatment by deep bed filtration can be improved by taking into consideration the distribution pattern in the secondary effluents. In raw sewage and primary effluents 45-90% of COD and 35-80% of phosphorus were associated with suspended solids. In the secondary effluents particulate COD drops to 14-45% but particulate phosphorus increases to 55-80%. Conclusions are drawn for a better design of advanced contaminant reduction in connection with suspended solids removal processes.
Effect of 1,1,2,2-Tetrachloroethane on the Performance of Upflow Anaerobic Sludge Bed (UASB) Reactors
Authors: Navarrete M. , Rodríguez N. , Amils R. , Sanz J. L.
Published: May 2018

Chlorinated aliphatic hydrocarbons (CAH) are important environmental pollutants since they are industrially used for a wide variety of applications. Chlorinated hydrocarbons are cited as important contributors to the inhibition of anaerobic digestion. In this work, the effect of 1,1,2,2-tetrachloroethane (TCE) on the performance of upflow anaerobic sludge bed (UASB) reactors fed with sucrose synthetic wastewater has been studied. According to the results obtained it can be concluded the possibility to use UASB reactors with granular sludge to treat industrial wastewaters with a continuous content of TCE up to a concentration of 130 mg/l or with incidental punctual discharges of high concentration of the toxicant up to 400 mg/l. In all cases in which the activity of the reactor was inhibited a fast recuperation was observed.
In Situ Anaerobic Treatment of Leachate in Landfill Bioreactors
Authors: Pohland F. G. , Kim J. C.
Published: May 2018

Landfills often serve as ultimate receptors for residential, commercial and industrial wastes. Both hazardous and nonhazardous wastes may be codisposed, but with potential threats to public health and the environment if not properly managed. Therefore, an understanding of the fundamental attenuating mechanisms determining mobilization and potential transport and fate of codisposed waste constituents is needed to direct the selection of appropriate landfill operational and management strategies. By focusing on changes in leachate and gas characteristics during codisposed loadings of organic and inorganic hazardous wastes, the potential treatment capacity of bioreactor landfills with leachate containment and in situ recirculation could be demonstrated.
Excess Sludge Discharge Frequency for UASB Reactors
Authors: Cavalcanti Paula Frassinetti Feitosa , Medeiros Erly Joan Souto , Silva Jean Kanuto Menezes , van Haandel Adrianus
Published: May 2018

Like all biological wastewater treatment systems, the UASB reactor produces sludge that accumulates in the reactor. Since the storage capacity is limited, the sludge will eventually be discharged together with the effluent, when the reactor is full of sludge. To avoid the discharge of sludge in the effluent, it is necessary that excess sludge be discharged periodically from the reactor before its storage capacity is exhausted. For minimum operational costs it is preferable to have large discharges with a low frequency. On the other hand the discharges cannot be excessive in order to avoid deterioration of the reactor performance after the discharges.

An experimental investigation was carried out at pilot scale to establish the influence of the magnitude of excess sludge discharge on the performance of UASB reactors, treating municipal sewage. UASB reactors were operated at hydraulic retention times (HRT) of 4 and 8 h, and excess sludge discharges of varying magnitude were applied. The performance and operational stability of these reactors after the discharges were observed and the sludge accumulation and unintentional discharge (wash-out) with the effluent were determined. During periods of steady state without excess sludge discharge, the sludge production was determined from the settleable solids in the effluent.

The data show that for discharges of up to 50% of the sludge mass in reactors with HRT = 4 hours and 60% with HRT = 8 hours, the reactor efficiency and operational stability were affected very little and only during the first few days after the discharge. Discharges of up to 80% of the sludge did not cause instability, but a reduction of the COD removal efficiency was observed during 1 to 2 weeks after the discharge. Independent of the magnitude of sludge discharge, the effluent pH remained in the narrow range of 6.8 to 7.0 and the ratio between alkalinity (average 275 ppm CaCO3) and VFA concentration (average of 28 ppm HAc) was always very high so that there was never a danger of souring of the reactor contents. Based on the obtained experimental data an operational procedure for optimisation of excess sludge discharges was developed.

It is believed that along with the favourable natural conditions during the experimental investigation (average temperature of 27°C), the observed reactor stability can be attributed to a large extent to the design of the used phase separator, which is much more efficient than the conventional one. It is possible that results with a conventional UASB reactor would have been different.
Prediction of sediment build-up from analysis of physical network data
Authors: Gérard C. , Chocat B.
Published: May 2018

The localization of solid deposits in sewerage networks is basically due to clearly identified structural causes: shallow slope, loops, geometry of pipes, special structures, etc. Our purpose is to analyse the major role played by the structure of the network itself in localisation and development of the deposits it conveys.

The conceptual model proposed determines the theoretical risk of sediment build-up in each section of the sewerage network. It is a set of simple parametrized expert rules (and/or, if/then) based on the fact that silting-up is mainly a conjunction of several causes, and therefore occurs in preferential locations. These rules are then implemented by processing each section in three separate and successive stages: assessment of the different criteria used to estimate the vulnerability of the network, i.e. its likelihood of trapping solids at specific locations; assessment of the different criteria used to estimate hazard, i.e. the probability that there are effectively some solids to be trapped; combination of vulnerability and hazard rankings used logical operators, thereby classifying theoretical sediment build-up risk as very high, high, average, low, very low. The model's performance compared to measurements are: 67% accurate forecasts (zero theory-measurement deviation), 25% average forecasts (1 or 2 classes deviation), 8% incorrect forecasts (3 or 4 classes deviation).
Adsorption of Humic Substances onto β-FeOOH and its Chemical Regeneration
Authors: Teermann I. P. , Jekel M. R.
Published: May 2018

Removing humic substances is a challenge for process engineering in drinking water treatment. Various processes have been developed in the past. However, due to problems in efficiency, waste disposal or high operating costs, the search for new solutions still persists. In this investigation we tested a new sorbent, a highly active granulated iron hydroxide with the β-FeOOH modification, regarding its adsorption capacity and regenerability.

Three fulvic acids were used differing in molecular weight distribution and calcium content. Iron hydroxide showed high adsorption capacities for each of these fulvic acids. The dependency of adsorption on pH was comparatively small, whereas calcium improved DOC removal especially at pH-values higher than 6. Larger fulvic acid molecules were preferably adsorbed. Calcium free sodium hydroxide solution allowed complete regeneration. In a pilot plant study kinetic restrictions were obvious due to pore exclusion of high molecular weight substances. However the good results concerning adsorption capacity and regenerability encourage us to enlarge the pore sizes of β-FeOOH granules.
Application of genetic algorithms and fuzzy control to a combined sewer pumping station
Authors: Yagi S. , Shiba S.
Published: May 2018

In the present study, fuzzy logic control and genetic algorithms are applied to achieve improved pump operations in a combined sewer pumping station. Pumping rates are determined by fuzzy inference and fuzzy control rules corresponding to input variables. Genetic algorithms are used to automatically improve the fuzzy control rules through genetic operations such as selection, crossover and mutation. The effects of different fitness functions and learning conditions are investigated using a stormwater runoff model. It is found that current pump operations can be improved by adding the sewer water quality to the input variables and to the fitness function; the improved operations can reduce not only floods in the drainage area but also pollutant loads discharged to the receiving waters.