bluuebunny/crossref_metadata_2025 huggingface dataset:
Drying kinetics and stabilization of sewage sludge in lagoon in hot climate
Authors: Idris A. , Yen O.B. , Hamid M.H.A. , Baki A.M.
Published: May 2018

A sludge lagoon has been adopted as a simple and cost effective method for dewatering of sludge. The processes occurring in a sludge lagoon include thickening, dewatering, storage and stabilization; all happening simultaneously. The objective of this study is to determine the dewatering and drying rates at pilot-scale which occur in a lagoon having different design configurations. Two types of sludge lagoons with different initial sludge depth (0.75 m and 0.375 m) were investigated to measure the drying behavior and drying efficiency. The first design is a sludge lagoon with a clay bottom where the dewatering mechanisms are decanting supernatant and evaporation. The second design is a sludge lagoon installed with a sand and underdrains system, where the dewatering mechanisms are filtration or draining and evaporation. Sludge drying kinetic models with high fitness were plotted to describe the sludge drying behavior. Drying of sludge in a sludge lagoon with a clay bottom can best be described by an exponential function. Whereas, drying of sludge in a sludge lagoon with sand and underdrains system followed a logarithmic function. A lagoon designed with sand and underdrains system and having shallower sludge depth was the most efficient. The reduction in volatile solids was lower than 4% during the study period. The drying process proceeded with an increase in dryness and decline in pH value.
The SOIL-N/WEKU model system – a GIS-supported tool for the assessment and management of diffuse nitrogen leaching at the scale of river basins
Authors: Wendland F. , Kunkel R. , Grimvall A. , Kronvang B. , Müller-Wohlfell D.I.
Published: May 2018

The SOIL-N/WEKU model system was developed to estimate groundwater-borne nitrogen inputs into river systems. The core of this model system is composed of a soil nitrogen leaching model (SOIL-N) and a groundwater residence time/denitrification model (WEKU). The application of the model system was carried out in the framework of the EU-project RANR (Regional analysis of subsurface nitrogen retention and its impact on the nitrogen export from land to sea) for a macroscale study river basin in Germany (the Uecker basin, ca. 2,400 km2) and a mesoscale study catchment area in Denmark (the Gjern basin, ca. 200 km2). For both catchment areas, the modelled average nitrogen loads leached into the groundwater were about 40 kg N/ha a, while the remaining groundwater-borne nitrogen intake to rivers was quantified to an average of about 2 kg/ha a. The comparison with observed groundwater-borne riverine nitrogen loads showed a very good agreement, proving the key role nitrogen retention in groundwater plays in the two catchment areas.
Effluent polishing via pasture irrigation in Harare, Zimbabwe
Authors: Nhapi I. , Mawere M. , Veenstra S. , Gijzen H.J.
Published: May 2018

Harare, the capital city of Zimbabwe, is experiencing eutrophication-related problems in its downstream potable water supply source of Lake Chivero. This is due mainly to poorly treated sewage effluent encroachment into upstream rivers, especially Marimba River. Crowborough Pasture Irrigation farm is in the Marimba sub-catchment area and has 305 hectares of irrigated pastures. Studies started from July 2000 to August 2001 focusing on the pasture's management of nutrients (nitrogen and phosphorus) and their impact on Marimba River. Water and nutrient balances were developed. Reduction efficiencies for this pasture were found to be 84% for TN and 54% for TP. Both the Crowborough sewage treatment works and the pastures are overloaded. It was therefore concluded that the current system is no longer sustainable economically and environmentally. From the results of our study we recommend that additional treatment units be constructed at Crowborough sewage treatment works to meet current flows. Moreover, pasture management needs substantial improvement. Nutrient recovery should be enhanced by regular harvesting of pasture grass and converting cow dung into an economic commodity as manure for neighbouring residents. Maize cultivation is also recommended to replace pasture grass as it is a local staple crop and has high nutrient uptake rates.
Integrated watershed approach in controlling point and non-point source pollution within Zelivka drinking water reservoir
Authors: Holas J. , Hrncir M.
Published: May 2018

An agricultural watershed involves manipulation of soil, water and other natural resources and it has profound impacts on ecosystems. To manage these complex issues, we must understand causes and consequences and interactions-related transport of pollutants, quality of the environment, mitigation measures and policy measures. A ten year period of economic changes has been analysed with respect to sustainable development concerning Zelivka drinking water reservoir and its watershed, where agriculture and forestry are the main human activities. It is recommended that all land users within a catchment area should receive payments for their contribution to water cycle management. Setting up the prevention principles and best management practices financially subsidized by a local water company has been found very effective in both point and non-point source pollution abatement, and the newly prepared Clean Water Programme actively involves local municipal authorities as well. The first step based on systems analysis was to propose effective strategies and select alternative measures and ways for their financing. Long term monitoring of nutrient loads entering the reservoir and hazardous events statistics resulted in maps characterising the territory including vulnerable zones and risk factors. Financing involves providing annual payments to farmers, who undertake to manage specified areas of their land in a particular way and one-off payments to realise proposed issues ensuring soil conservation and watershed ecosystem benefits.
Removal of phosphate by seafood processing wasted sludge
Authors: Lee S.M. , Choi B.J. , Kim K.H.
Published: May 2018

There is a need for developing low cost, easily and abundantly available, yet efficient, adsorbents for the removal of phosphates during the tertiary treatment of wastewater. The wasted sludge from a cuttlefish processing factory prepared on a laboratory scale has been used to evaluate its performance for phosphate adsorption. The material has been shown to be a good alternative adsorbent. As much as 90% phosphate removal by the prepared sludge is possible in about 20 h under the test conditions. Phosphate removal is seen to increase with decreasing adsorbent particle size, increasing the relative concentration of phosphate to sludge and increasing adsorbent dose. Models for predicting phosphate removal incorporate operational variables such as the ratio of phosphate to wasted material and adsorbent dose. These models also manifest high values of the correlation coefficients. Calcium phosphate precipitation in the present experimental system is not a significant phosphate removal mechanism.
Land application technique for the treatment and disposal of sewage sludge
Authors: Zain S.M. , Basri H. , Suja' F. , Jaafar O.
Published: May 2018

Some of the major concerns when applying sewage sludge to land include the potential effect on pH and cation exchange capacity; the mobility and the accumulation of heavy metals in sludge treated soil; the potential of applying too much nutrients and the problems associated with odors and insects. The main objective of this study is to identify the effects of sewage sludge application on the physical and chemical properties of sludge treated soil. Sewage sludge was applied to soil at various rates ranging from 0 L/m2 to 341 L/m2. In order to simulate the natural environment, the study was carried out at a pilot treatment site (5.2 m × 6.7 m) in an open area, covered with transparent roofing material to allow natural sunlight to pass through. Simulated rain was applied by means of a sprinkler system. Data obtained from sludge treated soil showed that the pH values decreased when the application rates were increased and the application period prolonged. The effect of sewage sludge on cation exchange capacity was not so clear; the values obtained for every application rate of sewage sludge did not indicate any consistent behaviour. The mobility of heavy metals in soils treated with sludge were described by observing the changes in the concentration of the heavy metals. The study showed that Cd has the highest mobility in sludge treated soil followed by Cu, Cr, Zn, Ni and Pb.
Application of locally available materials for the treatment of organic polluted water
Authors: Salim M.R. , Othman F. , Imtiaj Ali Md. , Patterson J. , Hardy T.
Published: May 2018

Several types of water treatment technologies including adsorption are now being used to treat polluted water. In this paper the removal of phenol by adsorption will be discussed. Activated carbons are successfully applied for purification of potable water and the removal of organic pollutants in wastwater. This paper is concerned with a low cost approach to treating waste water that is significant especially for those countries where oil palm is an available agricultural product like Malaysia, Ivory Coast, Nigeria, Thailand, Papua New Guinea. In the coastal region coconut is an available agricultural product and activated carbon prepared using coconut shell is also an economical method of water treatment. The materials used in this study were Commercial Activated Carbon (CAC), prepared from coconut shell and Modified Oil Palm Shell (MOPAS) of 1 to 2 mm diameters. The surface area of CAC and MOPAS was 38.5 m2/g and 38.2 m2/g respectively and the iodine number was determined as 674 and 454 for CAC and MOPAS, respectively. From the study the result shows above 70% removal efficiency for 5 mg/L and 40% removal efficiency for 20 mg/L of phenol solution. The performance efficiency will be discussed based on batch test, following Freundlich adsorption isotherm.The results indicate that CAC exhibits a higher adsorptive capacity (Kf of 0.079) as compared to MOPAS (Kf of 0.048). Hence a better removal efficiency for CAC at lower concentration of phenol. Results from column tests show a better adsorptive capacity for CAC (2.73) as compared to MOPAS (2.48).
Limits of anaerobic biodegradation
Authors: Field J.A.
Published: May 2018

The main factors responsible for anaerobic recalcitrance are reviewed. Anaerobic recalcitrance is associated with hydrocarbons lacking functional groups, branched molecules (gasoline oxygenates), aromatic amines and aromatic sulfonates. The most recalcitrant compounds are high molecular weight non-hydrolyzable polymers such as plastic, lignin and humus, which cannot be taken up by cells. Recently new capabilities of anaerobic microorganisms have been discovered to degrade compounds previously considered to be recalcitrant. For example, anaerobic bacteria initiate the degradation of alkylbenzenes and alkanes with an unusual addition reaction with fumarate, forming a hydrocarbon-succinate adduct. Finally, new evidence indicates that the most recalcitrant compounds (humic substances) are not so inert and can play important roles in aiding the biodegradation of other compounds by serving as an electron acceptor or redox mediator.
Relationship between partition of heavy metals in sewage sludge and elution of heavy metals
Authors: Ito A. , Kusanagi J. , Matsukura T. , Aizawa J. , Umita T.
Published: May 2018

Heavy metals in sewage sludge were classified into three partitions associated with extracellular and intracellular organic matters and the residue before and after different elution processes of heavy metals from the sludge. Alkalization of the sludge to pH 11 decreased the content of Cu in the three partitions and that of Ni in extracellular organic and residual ones. Acidification of the sludge to pH 3 decreased the content of Cd, Mn, Ni and Zn in all of the partitions and that of Cu in the intracellular organic one. A further decrease in the pH to 2 caused a decrease in the content of Cu in extracellular organic and residual partitions and that of Ni in the inorganic one. The addition of ferric sulfate to the sludge effectively lowered the content of Cd and Cu in extracellular organic and inorganic partitions under acidic conditions. These results would give information on a selection of the method for removing heavy metals from the sludge.
Influence of electron donors and acceptors on the bioremediation of soil contaminated with trichloroethene and nickel: laboratory- and pilot-scale study
Authors: El Mamouni R. , Jacquet R. , Gerin P. , Agathos S.N.
Published: May 2018

Laboratory- and pilot-scale studies were conducted in order to adjust and optimize the in-situ conditions for bioremediation of a soil contaminated with trichlororethene (TCE) and nickel. Results from laboratory studies showed that the indigenous microorganisms of the soil were limited by the type of electron donor. A better TCE dechlorination was obtained when the electron donor was composed of a mixture of methanol and lactate, as compared to that with methanol alone. Addition of up to 10 mM of sulphate as external electron acceptor (in combination with TCE) and with a mixture of methanol and lactate as electron donor had no significant effect on the TCE reducing activity of indigenous microorganisms of the soil, while higher concentrations (15 and 20 mM) yielded a lower dechlorination. Long term operation of a large pilot-scale soil reactor demonstrated the feasibility of a single-process in situ soil remediation. Results showed that, on one hand, TCE was progressively and stepwise reduced to cis-dichloroethene (DCE), vinyl chloride (VC) and finally to ethene, using only the indigenous microorganisms of the soil. On the other hand, stimulating the activity of sulphate-reducing bacteria of the soil with the addition of sulphate as electron acceptor was efficient in precipitating nickel as nickel sulphide.
Minimization of sludge production in biological processes: an alternative solution for the problem of sludge disposal
Authors: Deleris S. , Geaugey V. , Camacho P. , Debellefontaine H. , Paul E.
Published: May 2018

A combined system associating activated sludge and ozonation was evaluated for the treatment of urban wastewater. Experiments have shown that 70% reduction in sludge production can be reached (compared to a reference system running in low loaded conditions Yobs = 0.28 g VSS.g COD-1) by applying an ozone dosage of 0.05 g O3/g VSStreated. Recycling of the ozonated sludge to the aeration tank induces a slight increase in effluent COD, but the biological treatment performance is maintained. Nitrification capabilities are not altered by the sludge reduction process and active biomass measurements revealed that autotrophic biomass seems to be less affected than the heterotrophs. Significant improvements in sludge settling characteristics are observed.
The IWA Anaerobic Digestion Model No 1 (ADM1)
Authors: Batstone D.J. , Keller J. , Angelidaki I. , Kalyuzhnyi S.V. , Pavlostathis S.G. , Rozzi A. , Sanders W.T.M. , Siegrist H. , Vavilin V.A.
Published: May 2018

The IWA Anaerobic Digestion Modelling Task Group was established in 1997 at the 8th World Congress on Anaerobic Digestion (Sendai, Japan) with the goal of developing a generalised anaerobic digestion model. The structured model includes multiple steps describing biochemical as well as physico-chemical processes. The biochemical steps include disintegration from homogeneous particulates to carbohydrates, proteins and lipids; extracellular hydrolysis of these particulate substrates to sugars, amino acids, and long chain fatty acids (LCFA), respectively; acidogenesis from sugars and amino acids to volatile fatty acids (VFAs) and hydrogen; acetogenesis of LCFA and VFAs to acetate; and separate methanogenesis steps from acetate and hydrogen/CO2. The physico-chemical equations describe ion association and dissociation, and gas-liquid transfer. Implemented as a differential and algebraic equation (DAE) set, there are 26 dynamic state concentration variables, and 8 implicit algebraic variables per reactor vessel or element. Implemented as differential equations (DE) only, there are 32 dynamic concentration state variables.
Start-up of a thermophilic methanol-fed UASB reactor: change in sludge characteristics
Authors: Paulo P.L. , Jiang B. , Roest K. , van Lier J.B. , Lettinga G.
Published: May 2018

Experiments were performed to study the change in sludge characteristics and sludge granulation during the start-up of a thermophilic methanol-fed upflow anaerobic sludge bed (UASB) reactor. The laboratory scale reactor, was inoculated with thermophilic granular sludge and operated at 55°C over 130 days at organic loading rates (OLR) varying from 2.7 to 47 gCOD.L−1.d−1. Physical characterisation was performed for both the seed and the cultivated sludge. Results demonstrated that a good quality, well settleable granular sludge was cultivated and retained in the reactor, allowing an OLR of 47 gCOD.L−1.d−1 with 93% of methanol removal, where 79% was converted into methane. Using a community analysis of the cultivated consortia, high numbers of rod-shaped hydrogenotrophic methanogens were enumerated. Biomass washout coincided with a high specific gas load, but was not detrimental to the system in the conditions tested.
Removal of 3-chlorobenzoate using an upflow anaerobic sludge blanket reactor under light conditions
Authors: Sawayama S. , Tsukahara K. , Yagishita T.
Published: May 2018

The possibility of 3-chlorobenzoate removal from water using an upflow anaerobic sludge blanket (UASB) reactor without the addition of any extra dechlorinating culture under light conditions has been studied on a laboratory scale. Benzoate removal was observed in the first three months of operation under light conditions, but the 3-chlorobenzoate removal was not observed. After three months of operation under light conditions, the 3-chlorobenzoate concentration in the UASB reactor effluent gradually decreased to less than 1 mg·L−1. The 3-chlorobenzoate concentration in the effluent did not increase under dark conditions. The DOC concentration in the effluent decreased according to the removal of the 3-chlorobenzoate by the UASB granules. These results indicated that granules in the UASB reactor provided the 3-chlorobenzoate removability after 80–100 d of adaptation to the 3-chlorobenzoate, and that the UASB reactor is useful for 3-chlorobenzoate removal.
Vermicomposting of sewage sludge: a new technology for Mexico
Authors: Cardosa Vigueros L. , Ramírez Camperos E.
Published: May 2018

In Mexico 31% of the treatment plants have a flow less than 60 l/s. This study offers a simple and economical alternative through vermicomposting to resolve the management of sewage sludge and water hyacinth for these small treatment plants. This study was developed with laboratory and pilot scale systems. In the laboratory Eisenia foetida survival was quantified. They were fed three doses of sludge and water hyacinth and different percentages of humidity were applied. The production of worm cocoons was quantified as biomass production and the reduction in the TV/STS ratio as an indicator of stability. To install the pilot system the mixture with the highest cocoon production was chosen. In the pilot test the effect of the worm population density on the waste degradation was observed, the experiment was divided into five modules, four with densities from 2.5 to 15 kg/m2 and one module without worms that served as a blank test. Results: the best mixture was 70% sewage sludge and 30% water hyacinth, with 80% humidity and an average production of 298 cocoons/kg of vermicompost. There were no significant differences in the TVS/TS reduction between the different modules with worms, but in the blank test module there was no reduction. The Type A vermicompost obtained, with non-restricted use, 900 fecal coliforms NMP/g, 0.0 helminth ova/g, highly organic (60% M.O.), high concentration of total nitrogen (2.5%), phosphorus (0.96%) and cationic exchange capacity (60.2 meq/100 g), which indicates that soil fertility would increase if used in agriculture.
Influence of pulsation on start-up of UASB reactors
Authors: Franco A. , Gresia G. , Roca E. , Rozzi A. , Lema J.M.
Published: May 2018

The aim of this work is to study the influence of pulsation on the start-up of lab-scale UASB reactors. Pulsation was produced by an Elastic Membrane Pulsator (EMP). The application of this device in previous works improved the performance of continuous fixed-bed fermentors and reduced the formation of preferential pathways, the retention of gas metabolites within the bed and the resistance to mass transfer. These characteristics seem to be suitable for feeding UASB reactors. In this work, the influence of pulsation frequency was studied in two pulsed UASB reactors operated in parallel with a non-pulsed one. One of them (P1) operated at high frequencies (periods of 50 and 200 s between each pulsation) and the other (P2) at low frequencies (periods of 3600 and 900 s between each pulsation). An important improvement of the removal efficiency for pulsed reactors with respect to the non-pulsed one was obtained. The structure of the biomass was observed at the end of the process by scanning electron microscopy. In general, granulation of biomass was improved when operating in pulsing form.
Anaerobic degradation of BTEX in a packed-bed reactor
Authors: de Nardi I.R. , Varesche M.B.A. , Zaiat M. , Foresti E.
Published: May 2018

A bench-scale horizontal-flow anaerobic immobilized biomass (HAIB) reactor was assayed aiming to verify its performance in degrading benzene, toluene, ethylbenzene and xylene (BTEX). A 138-ml HAIB reactor filled with polyurethane foam matrices containing immobilized anaerobic biomass was initially fed with synthetic substrate containing protein, carbohydrates and lipids. Thereafter, BTEX degradation was evaluated in the presence of the co-solvents ethanol and lineal alkylbenzene sulphonate (LAS), in two sequential experiments. The inlet BTEX concentration ranged from 1.3 to 27.0 mg/L of each compound and outlet concentrations were lower than 0.1 mg BTEX/L for both the experiments with ethanol and LAS. An active enriched microbial consortium was observed in the reactor, containing BTEX-degraders, and also acetogenic, acetotrophic and hydrogenotrophic microorganisms. The results from the most probable number (MPN) tests indicated a decrease in the number of methanogenic archae, while the number of anaerobic microorganisms in the biofilm was maintained during the experimental period. Methanogenic archae were found to represent less than 0.5 % of the total anaerobic organisms in the biomass inside the reactor.
State of the art and future perspectives of thermophilic anaerobic digestion
Authors: Ahring B.K. , Mladenovska Z. , Iranpour R. , Westermann P.
Published: May 2018

The state of the art of thermophilic digestion is discussed. Thermophilic digestion is a well established technology in Europe for treatment of mixtures of waste in common large scale biogas plants or for treatment of the organic fraction of municipal solid waste. Due to a large number of failures over time with thermophilic digestion of sewage sludge this process has lost its appeal in the USA. New demands on sanitation of biosolids before land use will, however, bring the attention back to the use of elevated temperatures during sludge stabilization. In the paper we show how the use of a start-up strategy based on the actual activity of key microbes can be used to ensure proper and fast transfer of mesophilic digesters into thermophilic operation. Extreme thermophilic temperatures of 65°C or more may be necessary in the future to meet the demands for full sanitation of the waste material before final disposal. We show data of anaerobic digestion at extreme thermophilic temperatures.
Novel anaerobic process for the recovery of methane and compost from food waste
Authors: Han S.-K. , Shin H.-S. , Song Y.-C. , Lee C.-Y. , Kim S.-H.
Published: May 2018

Multi-step sequential batch two-phase anaerobic composting (MUSTAC) process was used to recover methane and composted material from food waste. The MUSTAC process consists of five leaching beds for hydrolysis, acidification and post-treatment, and an upflow anaerobic sludge blanket (UASB) reactor for methane recovery. This process involves the combined methods of sequential batch operation and two-phase anaerobic digestion for simple operation and high efficiency. Rumen microorganisms are inoculated due to their enhanced cellulolytic activity. Each leaching bed is operated in a sequential batch mode. Five leaching beds are operated in a multi-step mode with a two-day interval between degradation stages. Acidified products in the leachate from the leaching beds are converted to methane in the UASB reactor. The MUSTAC process demonstrated that it was capable of removing 84.9% of volatile solids (VS) and converting 85.6% of biochemical methane potential (BMP) into methane at 10.9 kg VS/m3·d in 10 days. Methane gas production rate was 2.31 m3/m3·d. The output from the post-treatment of residues in the same leaching bed without troublesome moving met the Korean regulation on compost, indicating that it could be used for soil amendment.
Effect of carbon dioxide and ammonium removal on pH changes in polishing ponds
Authors: Cavalcanti P.F.F. , van Haandel A. , Lettinga G.
Published: May 2018

If nutrient removal is to be obtained in ponds treating sewage, the pH must be raised so that ammonia can desorb and phosphates can precipitate. In this paper it is shown that the pH increase in ponds can be predicted quantitatively from simple stoichiometry, taking into consideration physical and biological carbon dioxide removal, ammonia stripping and calcium carbonate precipitation. Biological CO2 removal by photosynthesis is identified as the main process to effect pH increase in ponds. The rate of pH increase and consequently the required retention time depend on the net rate of CO2 consumption, the extent of ammonium stripping, the characteristics of the influent (alkalinity and pH) as well as factors concerning the environment (temperature) and dimensions (depth) of the pond. A high pH (range 9 to 10) can be obtained in about 5 days if digested sewage is used (low organic material concentration), climate conditions are favourable and the pond is shallow (< 0.5 m deep).
Kissimmee River restoration: a case study
Authors: Whalen P.J. , Toth L.A. , Koebel J.W. , Strayer P.K.
Published: May 2018

Channelization of the Kissimmee River transformed a 167 km meandering river into a 9 metre deep, 75 metre wide, 90 km drainage canal (C-38) that is compartmentalized with levees and water control structures into a series of five stagnant pools. Channelization dramatically changed water level and flow characteristics, drained 21,000 hectares of floodplain wetlands and severely impacted fish and wildlife populations. A $500 million dollar restoration project will restore the ecological integrity of the river-floodplain system by reconstructing the natural river channel and reestablishing hydrologic processes. Sixty expectations have been established to quantify the ecosystem's recovery. The first phase of reconstruction was completed in February 2001 and included movement of 9.2 million cubic metres of earth to backfill 12 km of C-38, the explosive demolition of one water control structure, construction of two sections (2.4 km) of new river channel, and reestablishment of 24 contiguous km of river. Numerous social, political, and technical challenges have been encountered during the project's evolution. Recommendations are provided for future restoration projects.
Investing in river health
Authors: Bennett J.
Published: May 2018

Rivers provide society with numerous returns. These relate to both the passive and extractive uses of the resources embodied in river environments. Some returns are manifest in the form of financial gains whilst others are non-monetary. For instance, rivers are a source of monetary income for those who harvest their fish. The water flowing in rivers is extracted for drinking and to water crops and livestock that in turn yield monetary profits. However, rivers are also the source of non-monetary values arising from biological diversity. People who use them for recreation (picnicking, swimming, boating) also receive non-monetary returns. The use of rivers to yield these returns has had negative consequences. With extraction for financial return has come diminished water quantity and quality. The result has been a diminished capacity of rivers to yield (non-extractive) environmental returns and to continue to provide extractive values.

A river is like any other asset. With use, the value of an asset depreciates because its productivity declines. In order to maintain the productive capacity of their assets, managers put aside from their profits depreciation reserves that can be invested in the repair or replacement of those assets. Society now faces a situation in which its river assets have depreciated in terms of their capacity to provide monetary and non-monetary returns. An investment in river “repair” is required. But, investment means that society gives up something now in order to achieve some benefit in the future. Society thus has to grapple with the choice between investing in river health and other investments - such as in hospitals, schools, defence etc. - as well as between investing in river health and current consumption - such as on clothes, food, cars etc. A commonly used aid for investment decision making in the public sector is benefit cost analysis. However, its usefulness in tackling the river investment problem is restricted because it requires all benefits and costs to be measured in dollar terms, and many of the benefits arising from investments in river health are non-monetary.

In this paper, techniques that enable non-monetary values to be estimated in dollar terms are described. Applications of the techniques to the estimation of the environmental values of rivers are demonstrated. The values estimated are used to demonstrate the extent of returns that are possible from investing in river health.
Environmental value transfer: an application for the South East Queensland waterways
Authors: Robinson J.J.
Published: May 2018

Economic valuations of the environmental resources provided by the waterways of South East Queensland are required for the evaluation of proposed environmental management strategies. Due to time and funding constraints it is unlikely that the environmental resources for each tributary of the river system will be subject to individual and explicit valuation. This paper reviews the literature about the validity of environmental benefit transfer, identifying the protocol for undertaking such a study. It then describes a study designed to transfer the estimated value of water quality improvements for the Bremer River to other waterways in South East Queensland. The study addresses some of the shortcomings of stated preference techniques to value the environment, including improving the quality of the information provided to survey respondents and the reliability of their responses by adopting a citizens' jury approach to the valuation exercise. In addition, the study is expected to provide the results in a form that will facilitate the estimation of a demand function for water quality improvements that will be meaningful for environmental value transfer to other sites with similar water quality issues.
Community data - where does the value lie? Assessing confidence limits of community collected water quality data
Authors: Nicholson E. , Ryan J. , Hodgkins D.
Published: May 2018

Waterwatch is a national community-based monitoring network that aims to involve community groups and individuals in the protection and management of waterways. Waterwatch Victoria has the dual objectives of catchment education and water quality monitoring. The educational outcomes are evident, with the Waterwatch programme facilitating over 9,000 students to monitor more than 2,000 sites in waterways in 2000. This paper aims to assess the scientific value of community-collected data, through examining differences between Waterwatch data and professionally collected data. The study looked at all aspects of volunteer data collection, including data confidence protocols, equipment, and data analysis. All professional data was collated by the Victorian Water Quality Monitoring Network (VWQMN). The parameters examined in this study were turbidity, electrical conductivity (EC), pH and total phosphorus.

The level of agreement between community-collected data and professional data varied temporally and spatially. Waterwatch data for EC and pH appeared to be very similar to professionally collected data. Equipment used by Waterwatch volunteers for turbidity and total phosphorus appeared to be limited in accuracy to moderate ranges. Overall the VWQMN professionally collected data showed less variance, suggesting greater variability, potentially due to inaccuracies, in volunteer collected data.
Runoff characteristics of nutrients from citrus fruit grove and its effects on water area
Authors: Nishimura F. , Watanabe M. , Takahashi R. , Akase T.
Published: May 2018

In this study, field observations are carried out in order to make clear the runoff characteristics of pollutants from citrus fruit grove, especially nutrients such as nitrogen, phosphorus and other inorganic materials. Long-term observation in the test fields continued for more than 7 months and detailed observations during one rainfall are also carried out. From these observations, the following results are obtained. 1) Nitrogen concentration in grove soil leachate is usually in a range of 25 to 45 mgN/L, and the main component is nitrate, whereas phosphorus concentration is in a range of 0.1 to 0.8 mgP/L and the main component is phosphate. Concentration of nutrients is higher than that in environment around it. 2) Runoff loading rate of any materials from grove soil can be unified and expressed as a power function of the flow rate. In this case, runoff style of each material is characterized by the power coefficient βx. 3) It is understood that the runoff characteristics are affected by the pH and rate of rainfall, and the ways of affecting the runoff characteristics are different in each material. 4) It is also suggested that detailed investigations are required to estimate the effect of pollutant runoff because the runoff characteristics are widely changed by the rainfall characteristics.
The production of D-xylose by enzymatic hydrolysis of agricultural wastes
Authors: Cho C.H. , Hatsu M. , Takamizawa K.
Published: May 2018

Agricultural wastes, rich in D-xylose content, were hydrolyzed using the mixed crude enzymes produced by Penicillium sp. AHT-1 and Rhizomucor pusillus HHT-1. Shells of pistachio, peanut, walnut, chestnut, barley brans and sunflower seed peels, were used as raw or pretreated forms. Pretreatment was performed by milling or steam explosion. Enzymatic hydrolysis after steam explosion was more effective than milling processing. More than 13 g of D-xylose was produced from 100 g of milled pistachio shells, walnut shells, sunflower seed peels and peanut shells (less than 0.5 mm size) by the action of mixed enzyme solutions. A maximum of 36 g of D-xylose was produced from 100 g of milled pistachio shells when mixed enzyme solution, containing 3,000 U and 33 U per g of substrate with xylanase and β-xyosidase activities, respectively, was applied. The ratio of the enzymatic hydrolysis as compared to acid hydrolysis in this finding was 100%.
PHA (polyhydroxyalkanoate) production potential of activated sludge treating wastewater
Authors: Takabatake H. , Satoh H. , Mino T. , Matsuo T.
Published: May 2018

The main purposes of wastewater treatment systems are to remove organic pollutants, but it would be very attractive if there were a way to recover the organic pollutants as valuable organic materials. One of the possible ways to recover organic pollutants in wastewater is to convert them into polyhydroxyalkanoates (PHAs), which are biodegradable plastics. In this study, 18 activated sludge samples in 4 wastewater treatment plants (WWTPs) in Tokyo, Japan, were evaluated for their potential to produce PHAs by aerobic batch experiments with excess supply of acetate as the sole carbon source. The activated sludge samples tested had the capability to accumulate PHA up to 18.8% of dry cell weight on average, with the range of 6.0% to 29.5%. The results showed that the maximum PHA content was dependent on the influent more than on the operational conditions of the activated sludge, and that conventional activated sludge produced PHA as much as anaerobic-aerobic activated sludge did. The PHA content achieved in this study is still low, and further improvement is needed to put into practice the recovery process of organic pollutants as biodegradable plastics by activated sludge.
Toxicity assessment on combined biological treatment of pharmaceutical industry effluents
Authors: Inanc B. , Calli B. , Alp K. , Ciner F. , Mertoglu B. , Ozturk I.
Published: May 2018

This paper describes the wastewater characterization and aerobic/anaerobic treatability (oxygen uptake rate and biogas production measurement) of chemical-synthesis based pharmaceutical industry effluents in a nearby baker's yeast industry treatment plant. Preliminary experiments by the industry had indicated strong anaerobic toxicity. On the other hand, aerobic treatability was also uncertain due to complexity and unknown composition of the wastewater. The work in this study has indicated that the effluents of the pharmaceutical industry can be treated without toxicity in the aerobic stage of the treatment plant. Methanogenic activity tests with anaerobic sludge from the anaerobic treatment stage of the wastewater treatment plant and acetate as substrate have confirmed the strong toxicity, while showing that 30 min aeration or coagulation with an alum dose of 300 mg/l is sufficient for reducing the toxicity almost completely. Powdered activated carbon, lime and ferric chloride (100-1,000 mg/l) had no effect on reduction of the toxicity. Consequently, the pharmaceutical industry was recommended to treat its effluents in the anaerobic stage of the nearby baker's yeast industry wastewater treatment plan at which there will be no VOC emission and toxicity problem, provided that pretreatment is done.
Effect of chemical treatment on soluble residual COD in textile wastewaters
Authors: Dulkadiroglu H. , Dogruel S. , Okutman D. , Kabdaşlı I. , Sözen S. , Orhon D.
Published: May 2018

The effect of chemical treatment on the magnitude of soluble residual COD in the biological treatment effluent is investigated for knit fabric finishing wastewater. Bentonite is selected for its potential to remove soluble COD together with color and particulate components. Chemical treatment using bentonite, when applied prior to biological treatment removes around 40% of the biodegradable as well as soluble inert COD initially present in the wastewater. As a chemical post-treatment, it acts as a polishing step, removing particulate matter and a minor portion of around 20% of the remaining soluble COD. These findings suggest chemical pre-treatment as a better alternative for the optimization of soluble COD removal.
Factors affecting colour removal from reactive dye bath by ozonation
Authors: Kabdaşlı I. , Ölmez T. , Tünay O.
Published: May 2018

A reactive dye bath sample containing a mixture of dyes was ozonated and colour removal was obtained in a relatively short time of 30 min at 605 mgl-1 of ozone utilisation. The factors affecting ozonation were assessed by comparing the results of dye bath and synthetic samples. Results from dye bath and synthetic dye solution ozonation were found to be significantly different. NaCl and Na2CO3 were determined to have a slight effect only on the initial rate of ozonation. However, the effect of the chelating agent in terms of both time and ozone dose was significant and explained the differences between the results of the dye bath and dye solution ozonation.
The effect of pre-ozonation on the H2O2/UV-C treatment of raw and biologically pre-treated textile industry wastewater
Authors: Arslan Alaton Í , Balcıog I.A.
Published: May 2018

Advanced chemical oxidation of raw and biologically pretreated wastewater by ozonation, H2O2/UV-C treatment and the successive combination of ozonation and H2O2/UV-C oxidation was investigated. For the raw textile wastewater, the application of successive O3 + H2O2/UV-C oxidation enhanced the COD and TOC removal efficiency of the H2O2 (50mM)/UV-C process by a factor of 13 and 4, respectively. In case of the biotreated textile wastewater, the preliminary ozonation step increased COD removal of the H2O2(10mM)/UV-C treatment system from 15% to 62%, and TOC removal from 0% to 34%, but did not appear to be more effective than applying a single ozonation process in terms of TOC abatement rates. Enhancement of the biodegradability was more pronounced for the biologically pre-treated wastewater with a two fold average increase in the BOD5/COD ratio for the studied chemical oxidation systems.
Biological treatability of a corn wet mill effluent
Authors: Eremektar G. , Karahan-Gul O. , Germirli-Babuna F. , Ovez S. , Uner H. , Orhon D.
Published: May 2018

Corn wet mill effluents are studied in terms of their characteristics relevant for biological treatment. They have a high COD of mainly soluble and biodegradable nature, with practically no soluble inert components. They generate a relatively high level of soluble residual metabolic products, which affects the choice of the appropriate biological treatment and favors aerobic activated sludge process. Experimental assessment of process kinetics yields typical values. Hydrolysis of the slowly biodegradable COD, the rate limiting step for the utilization of substrate, is characterized by an overall rate coefficient, which is within the range commonly associated for the hydrolysis of starch.
Oxidation-reduction potential (ORP) regulation of nutrient removal in activated sludge wastewater treatment plants
Authors: Li B. , Bishop P.
Published: May 2018

Redox potential (ORP) regulation of nutrient removal in aeration tanks was tested for one year in three activated sludge wastewater treatment plants in Cincinnati, OH. The experiment results show a good relationship between ORP values and nutrient removal. Macro-biodegradation and sorption of substrate by activated sludge can significantly increase wastewater ORP, indicating the improvement of redox status of the bulk liquor. DO higher than 1.0 mg/L is necessary for good biodegradation and the improvement of liquid redox status. ORP values at higher temperatures (Twater=20–26°C) were lower than ORP values at lower temperatures (Twater=14–19°C), caused by the lower oxygen saturation capacity in wastewater and the more rapid oxygen consumption by microorganism under warmer conditions. Nitrification occurred at higher ORP values (380 mV) than did organic substrate oxidation (250mV). This verifies that different metabolic processes dominate in different ORP ranges. The pilot-scale experiment results demonstrate that the wastewater ORP values continued to increase throughout the whole 6-hour cycle when the influent COD was higher than 1,000 mg/L. For influent with low COD (40–120 mg/L), the wastewater ORP values did not increase in the second 3 hours of the cycle, during which time the microbial-biodegradation within the activated sludge floc dominated. High DO concentrations (6–8 mg/L) did not help improve the redox status. In fully-aerated wastewater, oxygen deeply penetrated into the activated sludge flocs, and microorganisms biodegraded the substrates within the flocs. Endogenous metabolism predominated.
The significance of denitrifying polyphosphate accumulating organisms in biological nutrient removal activated sludge systems
Authors: Hu Z.-R. , Wentzel M.C. , Ekama G.A.
Published: May 2018

In this paper the advantages and disadvantages of denitrifying PAOs (polyphosphat accumulating organisms) in conventional BNRAS (biological nutrient removal activated sludge) and external nitrification BNRAS (ENBNRAS) systems are evaluated, with experimental data exhibiting a range of anoxic P uptake from low (<10%) to very high (>60%). The results indicate that the specific denitrification rate of the PAOs on internally stored PHB COD is about 1/5th of that of the “ordinary” heterotrophic organisms on SBCOD, and the PAOs contribute little (maximum 20%) to the denitrification in BNRAS systems even when the anoxic P uptake is high (60% of the total P uptake). Considering the unpredictable nature of anoxic P uptake and the reduction in BEPR it causes compared with aerobic P uptake BEPR, it is concluded that anoxic P uptake does not add a significant advantage to the BNR system.
Population dynamics in wastewater treatment plants with enhanced biological phosphorus removal operated with and without nitrogen removal
Authors: Lee N. , la Cour Jansen J. , Aspegren H. , Henze M. , Nielsen P.H. , Wagner M.
Published: May 2018

The population dynamics of activated sludge in a pilot plant with two activated sludge systems, both designed for enhanced biological phosphorus removal (EBPR), but one of them with (BNP) and the other without (BP) nitrogen removal, was monitored during a period of 2.5 years. The influent water to the pilot plant was periodically manipulated by external addition of phosphorus (P), acetate and glucose, respectively. The population dynamics and the in situ physiology were monitored by quantitative fluorescence in situ hybridization (FISH) and microautoradiography. Significant P removal was observed in both systems throughout the whole period, with significant increases of the P removal when substrates were dosed. The activated sludge in both systems contained large amounts of dense clusters of gram-negative, methylene-blue staining coccoid rods during the whole period. A large part of the clusters belonged to the β Proteobacteria, whereas the rest of the clusters belonged either to the Actinobacteria or to the α Proteobacteria. The relative abundance of Rhodocyclus-related bacteria in the activated sludge varied significantly in both systems during the whole period (from 6 to 18% in BNP, and from 4 to 28% in BP). However, no statistically significant correlation of the Rhodocyclus-related nor any of the other investigated bacterial groups to the P content of the activated sludge (correlation for all groups investigated was always < 0.5) was observed. A significant 33Pi uptake was observed by the β Proteobacteria (part of them Rhodocyclus-related, the identity of the rest unknown) and the Actinobacteria. However, not all of the Rhodocyclus-related bacteria showed 33Pi uptake. The P removal in the investigated plants is thus believed to be mediated by a mixed population consisting of a part of the Rhodocyclus-related bacteria, the Actinobacteria and other, yet unidentified bacteria.