bluuebunny/crossref_metadata_2025 huggingface dataset:
Wastewater Disposal by Sub-Surface Trickle Irrigation
Authors: Oron G. , DeMalach Y. , Hoffman Z. , Keren Y. , Hartman H. , Plazner N.
Published: May 2018

Field experiments were conducted to evaluate the reuse of domestic, secondary treated wastewater for irrigation of edible crops. Corn was irrigated under on-surface and subsurface trickle systems with effluent and compared with on-surface trickle irrigation applying fresh water.

The results indicate that under sub-surface trickle irrigation fruit contamination is minimal.
Control of Industrial Wastewater Discharges in the North West of England
Authors: Belshaw C. , Fisher T. J.
Published: May 2018

North Nest Water (NHW) manage a scheme to ensure the efficient control of industrial effluent discharges to protect the environment, the Company's assets, assist in meeting short- and long-term Water Quality objectives, whilst highlighting present and future problems.

Guidelines have been developed based on a policy of encouraging the treatment of industrial effluent in admixture with domestic sewage, provided that this can be satisfactorily achieved. Discharges of industrial effluent can be made only with the consent of the controlling Company and an extensive service for the reception and treatment of industrial effluent is offered.

The legal framework necessary to facilitate control, evolved over many years, has continued to develop and expand to encompass U.K. and European legislation. Aspects relevant to industrial effluent control and regulation are outlined and discussed.

Charging for the reception, conveyance and treatment of industrial effluent forms an important part of the control mechanism and ensures that industry pays a fair price for the service provided.

Increasing pressure to reduce inputs to the environment of dangerous substances has resulted in legislation, both national and international, which has a major impact on the business of waste water treatment. A description of the U.K. approach to the incorporation of European Community and North Sea conference requirements into its own legislative framework is included.
Sensory and Chemical Characterization of Fish Tainted by Exposure to Oil Sand Wastewaters
Authors: Koning C. W. , Hrudey S. E.
Published: May 2018

To investigate the potential for fish tainting from exposure to oil sands extraction wastewaters, rainbow trout were exposed to four different tailings pond wastewaters for a period of 24 hours. Subsequently, the fish were sacrificed, filleted and bile drawn from the gall bladder. Sensory analysis, performed by 10 pre-screened panelists, revealed that each of the four wastewater streams tainted the exposed fish to a detectable degree. Chemical analyses of the fish fillet, wastewater and fish bile revealed the presence of alkylated benzenes and phenols. The total level of phenols detected in the fish tissue was well above reported odour threshold levels. The additional presence of organic sulphur compounds identified in the wastewater suggests that they may also have contributed to the detected level of fish taint.
The Source of 2,6-Dibromophenol: Cause of an Iodoform Taint in Australian Prawns
Authors: Whitfield F. B. , Shaw K. J. , Walker D. I.
Published: May 2018

The presence of 2,6-dibromophenol in prawn meat in concentrations above 60 ng/kg produces a detectable iodoform-like flavour. This compound is usually accompanied by other bromophenols including .2- and 4-bromophenol, 2,4-dibromophenol and 2,4,6-tribromophenol. Previous studies have suggested that some marine algae and bryozoa from the Gutters region of Exmouth Gulf, Western Australia, were the possible sources of these compounds in the local endeavour prawn Metapenaeusendeavouri. Recently, a selection of eight marine algae, two bryozoa, a hydroid and eight sponges were collected from this region and were extracted by simultaneous distillation-solvent extraction. The extracts were analysed for bromophenols by high resolution gas chromatography-multiple ion detection-mass spectrometry. Quantitative data were obtained on individual compounds by the use of 3,5-dimethyl-2,4,6-trichloroanisole as an internal standard. 2-Bromophenol, 2,4- and 2,6-dibromophenol and 2,4,6-tribromophenol were shown to be present in all species and 4-bromophenol in all but two species of marine algae. The concentrations of these compounds varied from 0.1 µg/kg for 4-bromophenol in a marine algae to 240 µg/kg for 2,4,6-tribromophenol in a sponge. The highest concentration of 2,6-dibromophenol was found in a bryozoan (96 µg/kg) and the lowest in a marine algae (0.29 µg/kg). In general, there was about 30 times more of the latter compound in the bryozoa than in the algae. Sponges contained about one twelfth of that found in bryozoa. This paper discusses the significance of these results for the possible origin of 2,6-dibromophenol in endeavour prawns, taking into account the latest data available on the feeding habits of penaeid prawns.
Flavour Compounds in Weakly Polluted Rivers as a Means to Differentiate Pollution Sources
Authors: Jüttner F.
Published: May 2018

The volatile organic compounds of eight weakly polluted small rivers and brooks in SW Germany were studied by GC-MS. Special emphasis was placed on the differentiation between biogenic and anthropogenic sources and the use of particular compounds or patterns of compounds to characterize the pollution sources. Mono- and sesquiterpenes, which were liberated by wood processing industries, could clearly be distinguished from those which came from odorants of household detergents. In nearly every water sample geosmin was present while 2-MIB was not found in a single case. Nor-carotenoids were frequently observed in all river waters. The seasonal occurrence (summer) of 3-butenylisothiocyanate in several river waters was unexpected. Experiments with rape plants and soil from rape fields showed that this compound is leached from rape. However, the source of methylisothiocyanate that notoriously occurred in one river could not be established (acarizide or biogenic). Different patterns of esters were used to differentiate between the discharge of a paint manufacturer and a sewage treatment plant. Linear and cyclic hydrocarbons could be divided into a biogenic and anthropogenic fraction. Alkyl benzenes were found only in those rivers which were affected by industrial activities.
Biodegradation of 2-Methylisoborneol by Gravel Sand Filtration
Authors: Sumitomo H.
Published: May 2018

2-Methylisoborneol (MIB) and geosmin produced by blue-green algae were successfully removed in a new gravel filter plant. Small amounts of sludge were sampled from the filter layer and the bacteria able to decompose MIB were isolated from the sludge samples. By-products of the MIB degradation by these bacteria were also investigated. Among these bacteria, efforts were mainly focused on Pseudomonas fluorescens. The components of cell free extracts of this bacterium were studied in order to verify the biological reactions in vitro. 2-Methylenebornane, 2-methyl-2-bornene and isomers of these compounds were found to be a part of the by-products of the MIB degradation in the gravel filter.
Physiology of Geosmin Production by Anabaena circinalis Isolated from the Murrumbidgee River, Australia
Authors: Bowmer K. H. , Padovan A. , Oliver R. L. , Korth W. , Ganf G. G.
Published: May 2018

Chemical analysis and sensory assessment of river waters from the Murrumbidgee and Murray Rivers showed geosmin is an important odor compound. Experiments in culture using Anabaena circinalis isolated from the Murrumbidgee River, New South Wales, Australia showed that changes in chlorophyll per unit dry weight resulting from alterations in light intensity were paralleled by similar changes in geosmin/dry weight such that geosmin concentration was correlated with chlorophyll a over an extreme range of light conditions. A.circinalis was a prolific producer of geosmin, but a substantial proportion of the total geosmin was often retained intra-cellularly and released on sonication or treatment with copper. Therefore water treatment processes should avoid cell lysis.
Chemical Perception and Response of the Nile Tilapia to Geosmin
Authors: Kawamura G. , Nakaizumi H. , Motohiro T.
Published: May 2018

Chemical sensitivity of the Nile tilapia Tilapianilotica to geosmin was examined by the cardiac method. The fish showed cardiac deceleration in response to geosmin of various concentrations. The threshold of detection was found to be as low as 0.005 ng/l, which was lower than in humans by 3 orders of magnitude. Fish whose olfactory rosettes were removed also showed the cardiac response to geosmin, but the threshold increased by 2 orders of magnitude. This indicates that the olfactory organ can detect geosmin at very low concentrations, but that other chemoreceptors (taste buds and free neuromasts) are also important. When geosmin at concentrations of 0.04 to 40,000 ng/l was introduced into tanks, free swimming fish did not appear repelled nor attracted.
Protocol for Source Toxicity Evaluation
Authors: Eckenfelder W. W. , Lankford P. W.
Published: May 2018

Recent legislation in the United States is placing emphasis on the removal of priority pollutants and aquatic toxicity from industrial wastewaters. A protocol has been developed to select candidate technologies for specific effluent objectives. Wastewaters which are non-biodegradable and toxic are designated for source treatment. Design parameters for biological treatment are developed using a modified FBR test. The applicability of alternative physical-chemical technologies are discussed.
The Treatment of Wastewater from Coke Oven and Chemical Recovery Plants by Means of Bioferric Process – An Innovative Technique
Authors: Littleton X. , Ren Z.
Published: May 2018

The treatment of wastewater from coal-derived liquor is considered to be extremely difficult because of large quantities and fluctuating concentrations of toxic chemicals. This paper describes the performance of an innovative technique, - the Bioferric process as it compared to conventional activated sludge during pilot, semiscale and full-scale tests of wastewater treatment coke oven and chemical recovery plants.

Bioferric sludge uses the affinity of ferric hydroxide floc for the bacterial surface to create a dense, strong adsorptive and good settling sludge. As a result, the biomass can be operated at 7,000 to 9,000 mg/l, with SVI ranging between 50 to 90 and F/M ratios of 0.1. These levels can be realized without requiring additional oxygen. Due to the low F/M ratio, sludge production is markedly reduced. An additional benefit is iron-rich enhances sludge dewatering.

The pilot study showed that the bioferric process maintained average phenol removal at 99.93% even with influent cyanide as high as 40 mg/l. Especially under accidental spills, BOD, COD and cyanide removal were still at 98%, 81.3% and 98% respectively. In contrast, phenol, BOD, COD and cyanide removal were 80.7%, 19.7%, 25.8% and 72% respectively using conventional activated sludge. Full-scale tests confirmed the conclusions of the pilot study under conditions with high fluctuations of influent flow rate and toxic contents. They showed that the bioferric process always maintains a stable operation with effluent phenol, cyanide, BOD far below the required discharge standards and all at negligible increased cost.
Potential Problems Using the TCLP to Determine BDAT Compliance
Authors: Reynolds C. C.
Published: May 2018

A major result of the Land Disposal Restrictions (LDR) is that all listed hazardous wastes must be treated prior to land disposal. When evaluating treatment options, generators will want to know whether the treated waste meets the Best Demonstrated Achievable Technology (BDAT) criteria for land disposal. To avoid enforcement action and penalties, analytical data must confirm that the treated waste meets BDAT criteria.

Many BDAT criteria are based on the constituent concentration in the Toxicity Characteristic Leaching Procedure (TCLP) extract of the waste. Since the TCLP uses an acidic solution to leach the waste constituents, reported results may be influenced by hydrolysis, interfering compounds or laboratory contamination. Sufficient quality assurance samples must be analyzed for the data to be court defensible.

This paper proposes methods for minimizing analytical problems and obtaining representative data. A case illustrates several of the problems and related solutions.
Transformation of Wastewater in Sewer Systems – A Review
Authors: Nielsen Per Halkjaer , Raunkjær Kamma , Norsker Niels Henrik , Jensen Niels Aagaard , Hvitved-Jacobsen Thorkild
Published: May 2018

Many chemical, physical and biological transformations of wastewater in sewer systems may take place and cause significant changes in the composition during transportation. This paper focuses on the methods for measuring changes in wastewater composition (organic matter, dissolved oxygen, nitrogen and sulfur compounds), characteristics for changes in wastewater composition and empirical equations for oxygen uptake rates, sulfide production rates and BOD removal rates in both pressure mains and gravity sewers. Simple and more complicated biofilm models are evaluated for use in sewer systems, but so far no suitable advanced model for sewer biofilms exists, due to a lack of quantitative information about the transformations in such high-loaded multispecies biofilms.
Metabolism of Organic Substances in Anaerobic Phase of Biological Phosphate Uptake Process
Authors: Matsuo Tomonori , Mino Takashi , Sato Hiroyasu
Published: May 2018

Biochemical mechanisms of anaerobic uptake of organic substrate by anaerobic-aerobic activated sludge were investigated experimentally. As the organic polymers stored in the cell, 3H2MB and 3H2MV were newly identified besides PHB and PHV. Conceptual pathways for the formation of PHA (polyhydroxyalkanoates) were postulated. It was suggested that the conversion of glycogen into PHA should be important for the mechanisms of biological excess phosphate removal.
Optimizing Nitrogen Removal Reactor Configurations by On-Site Calibration of the IAWPRC Activated Sludge Model
Authors: Lesouef A. , Payraudeau M. , Rogalla F. , Kleiber B.
Published: May 2018

This paper describes a modified version of the IAWPRC model and the techniques used to calibrate it on site. Growth rate of autotrophic bacteria and the inert wastewater fractions were measured by simple methods, both in laboratory pilots and on full scale.

Model predictions were compared to full scale results in large plants (> 100 000 P E). Measured autotrophic growth rates ranged from 0.3 to 0.65 1/d, depending on wastewater toxicity. Most model constants compared well with original IAWPRC proposals, and several wastewater types were identified. Parameters to establish a suspended solids balance are given.

Different configurations of plants for nitrogen removal were investigated, including conventional recirculation, sludge reaeration (RDN) and step feed alternate zone denitrification.
Estimation of Kinetic Parameters of Heterotrophic Biomass under Aerobic Conditions and Characterization of Wastewater for Activated Sludge Modelling
Authors: Kappeler J. , Gujer W.
Published: May 2018

To predict the behaviour of biological wastewater treatment plants, the Activated Sludge Model No. 1 is often used. For the application of this model kinetic parameters and wastewater composition must be known. A simple method to estimate kinetic parameters of heterotrophic biomass and COD wastewater fractions is presented. With three different types of batch-tests these parameters and fractions can be determined by measuring oxygen respiration. Our measurements showed that the maximum specific growth rate µmax of heterotrophic biomass depends on temperature, reactor configuration and SRT. In typical wastewater treatment plants of Switzerland the amount of readily biodegradable substrate was generally small (about 9 % of the COD in primary effluent). The same method can also be used to determine kinetic parameters of nitrifying biomass.
Nitrification Kinetics in Single-Sludge Biological Nutrient Removal Activated Sludge Systems
Authors: Randall C. W. , Pattarkine V. M. , McClintock S. A.
Published: May 2018

Nitrification kinetics as a function of mixed liquor temperature were compared for a conventional fully-aerobic activated sludge system and a system accomplishing biological nutrient removal (BNR) by incorporation of anaerobic and anoxic zones using the UCT configuration. The systems treated the same municipal wastewater and both had flow rates of 151 L/day. The nitrification rates were greater in the nutrient removal system compared to the conventional system as long as the aerobic MCRT was above the minimum for complete nitrification. It was concluded that BNR systems require less aerobic volume than fully aerobic systems to accomplish nitrification because the aerobic biomass concentration is greater in the BNR systems, particularly if the UCT configuration is used. Nonetheless, BNR systems require more total volume to accomplish complete nitrification than fully aerobic systems, and the volume differential increases as mixed liquor temperatures decrease.
Control Parameter Variations in an Anaerobic Fluidised Bed Reactor Subjected to Organic Shockloads
Authors: Mathiot S. , Escoffier Y. , Ehlinger F. , Couderc J. P. , Leyris J. P. , Moletta R.
Published: May 2018

A pilot fluidised bed reactor was subjected to shockloads using wine distillery wastewater. The parameters' response was recorded. Parameters analysed in the gaseous phase were : H2, CH4, CO2 and gas production; in the liquid phase : pH, temperature, TOC and VFA.

Different shockloads were applied : short but intensive shockloading, long shockloadings; temperature variations; change of nature of substrate (wine distillery wastewater was replaced by glucose). Generally speaking, the parameters' response was short (less than one hour).

The specific parameters of the gaseous phase and pH can be used for the optimal control of the fermentation process.
Thermophilic Anaerobic Digestion of Vinasse in Pilot Plant UASB Reactor
Authors: Souza M. E. , Fuzaro G. , Polegato A. R.
Published: May 2018

Vinasse from sugar-cane alcohol production is generated in great amounts in Brazil and is disposed on soil “in natura”. Only a few distilleries use mesophilic anaerobic digestion, so far, for gas recovery and vinasse treatment or conditioning, due to an unfavorable economical balance.

Thermophilic anaerobic digestion was studied in a large-scale pilot-plant (75 m3 UASB reactor), since vinasses are generated at high temperatures, and no experiments on this subject are reported in the literature, except for a few laboratory assays using pure substrates and other wastewaters.

This work demonstrates the feasibility of sugar-cane vinasse thermophilic anaerobic digestion in UASB reactors.

The reactor was operated for 280 days, as far as possible like a full-scale plant; at applied organic loading rates of 25-30 kg COD/m3.day, 72% COD removal and 10 Nm3gas/m3.day could be achieved. Granulation of the sludge was essential in order to maintain good stability of the process; almost no soda was necessary for pH control.

For full-scale implementation, re-start of the thermophilic process, after several months without feeding, has to be studied yet.
Anaerobic Degradation of Municipal Wastes in Landfill
Authors: Attal A. , Akunna J. , Camacho P. , Salmon P. , Paris I.
Published: May 2018

The objective of this study was to analyze the degree of decomposition of municipal solid waste (MSW) placed in a landfill site and, based on this analysis, to propose an investigatory procedure to be used to assess the energetic potential of any site.

A sampling technique was developed in order to reduce the size of the MSW sample to 25-30 kg with an acceptable error of 20 %. Profiles of the strata were established which have shown a well ordered structure in horizontal layers corresponding to different MSW ages. The location of the two drill holes were chosen consequently. A sample per MSW age was carried out for each drill hole. Their degradation states were measured using an accelerated biodegradability test which also gives the methane potential.

For all samples, the evolution of four parameters, temperature, % CH4, % VSS and methane potential, were analysed as a function of their age. Anaerobic microbial activity was detected in the top layer of the landfill, showing that refuse starts as soon as deposited to undergo anaerobic transformation. Indeed, the % CH4 reaches its maximum value of 60 % between 5 and 10 m. Temperature increases from about 26°C to 50°C in the first 15 m and stays at this maximum value. That shows that municipal wastes are degraded under mesophilic and thermophilic conditions.

Two relations between waste age and % VSS, and waste age and the energetic potential have been demonstrated. The % VSS represents about 65 % of the dry mass for the fresh wastes and is quite low for the 6 year-old refuse. This rapid waste transformation rate could be due to optimal conditions for anaerobic activity existing in the landfill. The methane potential is proportional to waste age, almost zero for the 6 year-old refuse and greater than 45 1.kg.−1 for fresh wastes. These results show that a simple and rapid measurement of the % VSS of an unknown sample could be a good indication of its age and its degradation state.

As a result of this study, a two-step procedure has been developed that enables an evaluation of the energetic potential of a landfill site. The first step is to collect all the general information on the site, thus providing an initial estimate of the decomposition degree within the mass of the waste. The second step is then to confirm this estimation by sampling and analysing a few samples taken at shallow depths.
Dry Anaerobic Conversion of Municipal Solid Waste by Means of the Dranco Process
Authors: Six W. , De Baere L.
Published: May 2018

The Dranco process has been developed for the conversion of solid organic wastes, specifically the organic fraction of municipal solid waste (MSW), to energy and a humus-like final product, called Humotex. The Dranco process can be compared to landfill gas production, accelerated by a factor 1000. A Dranco installation with a digester of 808 m3 treating 10,500 tons of source separated waste per year will be constructed in 1991 at Brecht, Belgium. A description of the plant is elaborated. A demonstration plant of 56 m3 has been in operation for several years in Gent, Belgium using mixed garbage as a feedstock. The operating temperature in the digester is 55°C and the total solids concentration is ca. 32%. The mean gas production rate is 3.33 Nm3 CH4/m3reactor.day. The volumetric loading is 17.3 kg COD/m3reactor.day and the COD reduction is 55%. The gas production process is finalized in 3 weeks. The final product is dewatered and further stabilized in a 10 day aerobic post-treatment. The Humotex is free of pathogens. Low concentrations of heavy metals can only be obtained through separate collection of garbage. The Dranco process then also focusses on the digestion of source separated waste such as vegetable, fruit, garden and non-recyclable paper waste.
High Rate Anaerobic Digestion of Wool Scouring Wastewater in a Digester Combined with Membrane Filter
Authors: Hogetsu A. , Ishikawa T. , Yoshikawa M. , Tanabe T. , Yudate S. , Sawada J.
Published: May 2018

The performance and sludge diminution property in wool scouring wastewater treatment of an anaerobic process in combination with an ultrafiltration membrane (UFM) was evaluated. With regard to TOD removal, both mesophilic (37°C) and thermophilic (53°C) digestion, without UFM, showed the same trend of decreasing sharply from about 90 % to 30 % in proportion to the increasing TOD loading rate from 3 to 45 kg/m3· d. When a digester was provided at the effluent line of a reactor with UFM separator, about two times higher concentration of biomass was retained and the quality of the effluent improved remarkably due to better filtration. TOD and grease removal improved remarkably from 45 to 90 % and 37 to 99 % respectively, at a TOD loading rate of 15 kg/m3 · d in both fermentative temperatures. Further, the effective recirculation system of rejected liquid from UFM was studied to diminish the quantity of sludge generated. The study revealed that 33 % of the incoming SS was biodegraded under the recirculation system for rejected liquid from UFM to reactor, while 17 % was achieved in one pass through the system at the same TOD loading rate. Deterioration in the flux rate of UFM was observed for the first 40 days of operation from 37 to 23 l/m2 · h which then gradually decreased to 17 l/m2 · h after 210 days of service.
An Experimental Study on the Transport of Sediment in Sewer Pipes with a Permanent Deposit
Authors: Perrusquía G. S.
Published: May 2018

An experimental study of the transport of sediment in a part-full pipe was carried out in a concrete pipe. The experiments were confined to bedload transport. The purpose of this study was to analyze the flow conditions that characterize the stream traction in pipe channels and their relationship to flow resistance and sediment transport rate. Three procedures used in this kind of experimental study were tested and found valid: 1) the vertical velocity distribution near the sediment bed can be described by the velocity-defect law, 2) the side wall elimination procedure can be used to compute the hydraulic radius of the sediment bed, and 3) the critical shear stress of the sediment particles can be obtained by using Shields' diagram. A relationship to estimate bedload transport, based on dimensional analysis, was proposed. This was expressed in terms of both flow and particle parameters as well as geometric factors. Further experimental work is recommended before this relationship can be fully incorporated in a simulation model for the analysis of storm sewers.
Characterization of Suspended Solids in Urban Wet Weather Discharges
Authors: Chebbo G. , Bachoc A.
Published: May 2018

The objective of this study is to reach a better understanding of the main characteristics of urban stormwater discharge pollution, by providing information on:–paniculate pollution, its importance in relation to dissolved pollution and its abatement through decantation,–the grain size, the specific mass and the settling velocity of these solids.

The first part of this paper is given over to the presentation of the sites chosen and of the experimental methods put into operation.

In the second part we go on to analyze the results obtained for ten rainfall events over four different sites, according to their geographical position, to the type of network and to the size of the catchment basin. It is quite clear from the results obtained that the solids are the main vector of pollution. These solids are very fine (median diameter = 25 to 44 µn) and generally have a very high settling velocity (median settling velocity = 4 to 11 m/h). Thus it can be stated that decantation represents an efficient method to combat the pollution in urban stormwater discharge and this has been proved experimentally.
Bacterial Die-Off from Sewage Discharged through Submarine Outfalls
Authors: Bravo J. M. , de Vicente A.
Published: May 2018

The decrease of the concentrations of the indicator microorganisms of faecal pollution from the discharge point of sewage was studied in the marine area affected by the sewage discharges through three submarine outfalls located in the Southern Mediterranean coast of Spain. A noticeable decrease of the concentrations of the microbial indicators was observed after sewage disposal to the sea. Although the physical dilution affects the bacterial population levels, this process is not enough to justify the microbial decrease observed; for this, the biological inactivation process plays an important role in the microbial die-off in seawater. A bacterial reduction higher than 98% during the wastewater ascent towards the marine surface was achieved. These values imply a high bacterial inactivation during the initial dilution in addition to the physical process. Also, a fast decrease of the bacterial concentrations was observed from the upwelling point of wastewater at the sea surface; however faecal streptococci show a clearly longer survival than coliforms in the sea environment. On the other hand, the highest values of T90 and K were observed in summer.
Improvement of Bathing Water Quality by Reduction of Urban Outlets: Case Study for the Beach of Rødvig, Denmark
Authors: Jensen M. , Linde-Jensen J. J.
Published: May 2018

This paper describes a PC-package for simulation of bathing water quality. The actual case reported is the beach of Rødvig, SE Zealand, Denmark. The package computes time series and frequency distributions for E.coli, the indicator organism for bathing water quality. Point sources of pollution from combined sewer overflows (CSO) are computed from historical rain series and the existing MOUSE-package (Modelling Of Urban Sewers). Pollution from dry weather flow (DWF) (eg. purification plants) is also included. The bathing water model is based on time series for flow, dispersion and decay and is calibrated from measured frequency distributions in 4 stations within the period 1981-1986. A standard deviation factor STDe = 2.4 is achieved inbetween measured and computed distributions. Best fit values are obtained for 1) scaling factors er and es for pollution from CSO and DWF respectively, 2) diffuse (non-point) E.coli pollution Ed and 3) dispersion parameters Cb1 and Cb2 in the direction of coastline and vertical hereto. The calibrated model has revealed that an area of 102 ha along the beach exceeds the statistically acceptable quality line for bathing water. The paper presents 4 proposals for improving the quality by reducing the pollution from CSO and DWF, and/or by using an outfall pipe further into the sea for CSO.
Green Point Sewage Disposal Options
Authors: Fijen A. P. M. , Marsden M. G.
Published: May 2018

In the winter of 1989 severe seas destabilised the 1 700 metre long marine outfall at Green Point which had been commissioned in 1985. Divers had to detach a large section of the outfall to prevent further damage occurring. This resulted in virtually untreated sewage effluent being discharged 280 metres from the rocky shoreline. Public outrage and severe criticism from the media resulted in an emotional and environmentally sensitive issue having to be handled with considerable political and professional skill to enable the determination of the most appropriate solution for Green Point. Independent consultants were appointed by the Cape Town City Council to study basically two options to rectify the situation; reinstating the marine outfall or constructing a conventional sewage treatment plant in close proximity to a densely populated coastal area. This paper discusses the marine option in detail and the advantages and disadvantages of both marine and land options as well as the public involvement and the adopted decision making process. After a comprehensive investigation had identified and explored all aspects and after the public had been fully involved and consulted, the Cape Town City council accepted the City Engineer's recommendation with a vote of 33 to 1, in favour of a new marine outfall.
Modelling Microbial Concentrations from Multiple Outfalls Using Time-Varying Inputs and Decay Rates
Authors: Bell R. G. , Munro D. , Powell P.
Published: May 2018

In New Zealand, there are now increasing demands being placed on outfall investigations to accurately predict the fate of microbial contamination from proposed outfall options. In this context, a detailed numerical model study of proposed twin outfalls for the cities of Wellington and Lower Hutt focused on realistically simulating the dispersion and decay of faecal indicator bacteria. This meant including the effects of treatment level, adverse winds, light attenuation in the water column, time-varying discharge and decay rates, anticipated changes in the choice of faecal indicator bacteria, and the close proximity of two large outfalls. The relative importance of these input parameters in determining outfall lengths are discussed along with suggestions for future microbiological research; in particular the need for further microbial survival field experiments.
Quality Control of Numerical Models of Marine and Estuarine Effluent Outfalls
Authors: Copeland G. J. M.
Published: May 2018

Quality Control procedures were developed and implemented on behalf of a UK water company for the procurement of a suite of numerical models of advection and dispersion from effluent outfalls. The paper explains the need for quality control and describes the methods employed. These were a set of technical audits and performance trials. Some interesting technical issues arose from this work. These examined: the sensitivity of shoreline solutions to variations in parameter values; showed that simulations must be of sufficient duration to reach convergence; showed that the surface wind creates a shear dispersion effect which has an important effect on an effluent plume; and investigated the choice of diffusion coefficients with reference to along and across tide diffusivities and the need for consistency between nested models.
Unsteady Flow and Saline Intrusion in Long Sea Outfalls
Authors: Larsen T. , Burrows R. , Engedahl L.
Published: May 2018

The internal hydraulics of the multiport diffuser section in long sea outfalls has been studied by laboratory experiments and numerical modelling. The study has run for five years as a coordinated effort at both the University of Liverpool and the University of Aalborg. The investigations have covered such phenomena as saline intrusion, wave influence and unsteady flow caused by pump operation. Results show that numerous flow regimes exist depending on the boundary conditions. Numerical models have been developed to simulate the flow field in the diffuser section and some of the most interesting phenomena, in particular the wave induced saline intrusion, can now be modelled satisfactorily. Some aspects of the behaviour relating to very low fresh water discharges, e.g. unsteady flow when saline wedges are present, are still not very well described.
The Use of Micro/Ultrafiltration for the Removal of Oil and Suspended Solids from Oilfield Brines
Authors: Zaidi A. , Simms K. , Kok S.
Published: May 2018

Brine generated at offshore and onshore oil recovery facilities is generally treated for removal of oil and suspended solids to meet process and regulatory requirements. Microfiltration (MF) and Ultrafiltration (UF) have been proposed as effective and cost-competitive alternatives to conventional oil removal technology.

Recent studies in this field were reviewed to identify current trends and technical obstacles to the implementation of MF/UF technology for oilfield brine treatment. The most extensively demonstrated membrane technology for oilfield brine treatment in North America is a tubular ceramic microfiltration system which employs backflushing and chemical pretreatment. Two commercial installations of this technology are now in place, however, long term viability is uncertain.

Lack of an adequate database on both membrane/brine interaction and long term system operations have mitigated against the development of predictive models and correlations necessary to design membrane processes for removal of oil from oilfield brine. The key technical obstacles to cost effective application of membranes include low average flux rates, flux degradation and uncertain membrane life. Concerns regarding integration of membrane processes at oilfield brine treatment facilities include sensitivity to variations in flow and oilfield brine characteristics, handling of waste streams generated using chemical pretreatment and requirements for extensive prefiltration.
Development of the Slurry Precipitation and Recycle Reverse Osmosis (SPARRO) Technology for Desalinating Scaling Mine Waters
Authors: Pulles W. , Juby G. J. G. , Busby R. W.
Published: May 2018

Conventional desalination technologies such as electrodialysis reversal and reverse osmosis cannot be directly used to economically treat those waters encountered in the South African gold mining industry which are scaling with regard to calcium sulphate. The Chamber of Mines of South Africa Research Organisation therefore decided, in the early 1980's, to undertake research into the development of seeded reverse osmosis technology for treating scaling mine waters. This research culminated in the development of foe Slurry Precipitation and Recycle Reverse Osmosis (SPARRO) technology. Extensive pilot plant investigations were undertaken and it was shown that the SPARRO process is technically capable of producing a high quality product water at water recoveries of around 95 per cent. Problems were encountered, however, with fouling of the tubular cellulose acetate membranes, resulting in declines in the flux rate. It is postulated that the fouling is mainly due to the presence of quartzitic suspended material, although the mechanism of fouling cannot be explained. Further research is being undertaken to clarify the potential fouling mechanisms and to optimize the membrane cleaning regimes. The capital cost for a 46.3 1/s (4Ml/d) SPARRO plant has been estimated at R16.2 million, with an estimated operating cost of R 1.48/m3 of product water.
Current Status of Contamination by Persistent Organochlorines in the Lower Chao Phraya River, Thailand
Authors: Tabucanon M. S. , Watanabe S. , Siriwong C. , Boonyatumanond R. , Tanabe S. , Iwata H. , Tatsukawa R. , Ohgaki S.
Published: May 2018

Water and sediment samples collected from the lower Chao Phraya River and a canal along the river during 1988 - 1991 were analyzed to determine the current status of contamination by organochlorine pesticides, such as HCHs, DDTs, aldrin, dieldrin and chlordanes. Aldrin and dieldrin had high frequencies of occurrence in water samples. The medians of concentrations of these pesticides were approximately one order of magnitude larger than total HCHs and total DDTs. Residue levels of these pesticides varied significantly. Relatively higher levels of aldrin were observed in the upstream; in contrast, residue levels of DDTs were higher in urban area. These phenomena seem to relate to the spraying purpose of these pesticides. Decreasing trends in the residue levels of pesticides during monitoring periods, however, were not observed clearly. Residue levels of organochlorines in the sediment samples were in the order of magnitude of PCBs, DDTs, chlordanes and HCHs.
Sorption of Anionic Pentachlorophenol (PCP) in Aquatic Environments: The Effect of pH
Authors: Shimizu Y. , Yamazaki S. , Terashima Y.
Published: May 2018

The sorption of pentachlorophenol (PCP, pKa’ = 4.75) onto natural solids from aqueous phase was investigated by batch sorption experiments. The experimental aqueous phase was prepared for set values of pH (2 to 12) and ionic strength (0.1 M). Experimental results indicated that the sorption decreased with increasing pH over the entire pH range tested. A simple mathematical model, based on the hypotheses that the sorption coefficients of non-ionized and ionized species are different and the pH has only negligible effect on the natural solid characteristics, was applied to the pH range between 6 and 8, and the sorption coefficients (Kd) of both species were estimated. The Kd of ionized species (phenolate anion) was smaller than that of non-ionized species. The Kd of both species had poor correlation to the organic carbon content of natural solids. The Kd, however, correlated well with the swelling clay content and cation exchange capacity of natural solids. These results indicated that the sorption of PCP was not controlled by the organic carbon referenced hydrophobic sorption. For broader pH range (i.e., below 6 or above 8), the dependence of the natural solid characteristics on pH must be additionally included in the model.
Examination for Degradation Paths of Butyltin Compounds in Natural Waters
Authors: Watanabe N. , Sakai S. , Takatsuki H.
Published: May 2018

Examination of individual degradation paths (biodegradation and photolysis) of butyltin compounds (especially tributyltin: TBT) in natural waters was performed. Biodegradation of TBT and dibutyltin (DBT) in an unfiltered sea water in summer is rather fast; their half life is about a week. But pretreatment with glass fiber filter makes the half life of TBT much longer (about 80 days). Photolysis of TBT in sea water by sun light is rapid (half life is about 0.5 days), and faster than in distilled water or in fresh water. Degradation rates of each process for TBT are calculated in various conditions of sea water, and contribution rates are compared. Biodegradation will be the main degradation process in an “SS-rich” area such as a marina, but photolysis will exceed that in a “clean” area. Over all half lives of TBT in sea water vary from 6 days to 127 days considering seasons and presence of SS.
Polar Organic Pollutants on Their Way from Waste Water to Drinking Water
Authors: Schröder H. Fr.
Published: May 2018

The examination of pollutants in waste-, surface- and drinking water by sum parameters like COD, BOD or TOC gives no information about their toxicity or behaviour in the drinking water treatment process. As many pollutants leaving sewage treatment plants are polar and/or thermolabile, gas Chromatographic (GC) separation coupled on-line with a mass spectrometer (MS) is not applicable to this problem. Newly established analytical methods like high performance liquid chromatography (HPLC) in on-line combination with mass- (MS) or tandem mass spectrometers (MS/MS) using soft ionization techniques like thermospray (TSP) would help to solve these problems.

The comparison of GC- and LC/MS-spectra demonstrates increasing polarity beginning at the waste water treatment and ending at the drinking water treatment. It was possible to identify and quantify selected compounds, and elimination efficiency could be reviewed by comparing overview spectra.

The knowledge about the existence of these compounds in waste-, surface- and drinking water requires strategies for elimination, avoidance or degradation.
Evaluation of Mutagenicity of Municipal River Water Concentrated Using XAD Resin Column Method
Authors: Nakamuro K. , Ueno H. , Sayato Y.
Published: May 2018

The physico-chemical and mutagenic properties of organic concentrates from the Yodo river water were investigated using XAD resin column method with XAD-2, XAD-4 and XAD-8 under various adsorptive and desorptive conditions. XAD resin concentrates showed to be directly and indirectly frameshift mutagenic. Organic mutagens in the Yodo river water were almost absorbed to XAD-2 resin and then desorbed effectively with CH2Cl2. The physico-chemical properties of these concentrates were acidic and hydrophobic. Additionally organic mutagens which possess basic and hydrophilic properties may contribute to the mutagenicity.
Biodegradation Rate of Chloroethylene in Soil Environment
Authors: Yagi O. , Uchiyama H. , Iwasaki K.
Published: May 2018

Degradation rates of PCE and TCE were determined in lotus, rice and vegetable field soils. The lotus field soil had the highest ability to degrade tetrachloroethylene(PCE) and trichloroethylene(TCE). The values of T50(50% degradation time) in L-1 lotus soil were 8 and 15 days for PCE and TCE under the substrate concentration of 5 µg in 50ml of soil solution. PCE was biologically transformed to TCE in all soils. The material balance of PCE depletion and TCE production were determined. The degradation rates of PCE and TCE were significantly influenced by temperature and substrate concentration.
Ecotoxicological Contribution for the Economic Evaluation of Water Pollution Control Strategies
Authors: Vighi M.
Published: May 2018

A strategy for the control of environmental pollution should be based on three fundamental steps: a- assessment of the environmental aspects of the problem (exposure to pollutant chemicals, damages to man and the environment, etc ); b- economic evaluation (costs and benefits from chemical usage, evaluation of damages, etc ); c- institutional aspects (adoption of environmental standards, regulations, etc. ). Thus, an efficient collaboration between environmental and social sciences is of paramount importance in environmental decision making. To reach this objective it is essential to know exactly what kind of information can be produced by each science.

In this paper an integrated ecotoxicological approach, able to produce descriptive as well predictive results, is presented. Its application to an exercise of collaboration between ecotoxicology and socio-economical sciences is discussed. From this point of view, the case history of herbicide contamination of groundwater in Italy is described.
Carcinogenic Micropollutants in Drinking Water - Risks and Regulation
Authors: Fawell J. K.
Published: May 2018

A number of common contaminants in drinking water, arising as by-products of chlorination or from industrial pollution, have been shown to cause cancer in laboratory animals. The initiating event in the process of chemical carcinogenicity is usually considered to be the induction of a mutation in the DNA of a somatic cell. The process theoretically may not have a threshold. There are however some substances which are capable of producing cancer in animal studies but which cannot be shown to have genotoxic activity. The former are usually regulated by estimating the concentration in drinking water which gives rise to an acceptable risk of additional cancers in exposed populations. The mathematical models used in the process have many built in assumptions and will usually overestimate the true risk which could be zero. The latter, non-genotoxic carcinogens, are considered to operate through a mechanism which has a threshold and are usually regulated by applying uncertainty, or safety, factors to the no observed effect level in animal studies. Carcinogens often occur in water in mixtures and at present we have no appropriate means of taking this into account. However there is a sufficient margin of safety built into the regulatory approach to be confident that drinking water is not a significant source of cancer in most populations.
Study of the Nature of the By-Products Formed and the Risks of Toxicity when Disinfecting a Secondary Effluent with Ozone
Authors: Langlais B. , Legube B. , Beuffe H. , Doré M.
Published: May 2018

Among the disinfection processes of urban waste water, ozonation and UV irradiation are fast gathering interest. To avoid what happened with chlorine it is necessary to have a look at the formation of by-products and the risks of toxicity when such processes are used. We were already working on this type of problem in 1984, although we did not make a point of communicating in extenso the results obtained during a 2-year period of pilot plant and laboratory studies at La Roche sur Yon (Vendée, France). The present paper reminds of the changes in chemical nature of the effluent after an ozonation from 6 to 12 g O3/m3 resulting in an abatement of fecal coliforms and fecal streptococci to the extent of 3 to 4 logarithmic units. No evidence of compounds known for their toxicity was brought to light.

The toxicity tests performed on fish (Brachydanio rerio) and crustacean (Artemia nauplii) showed that the secondary effluent upstream or dowstream of the ozonation did not have toxic effects on the used biological material except for the fish when strong ammonia nitrogen concentrations occur. The toxicity tests performed on green algae (Scenedesmus subspicatus) showed that ozonated effluent seemed less conductive to algal growth than non ozonated effluent.