bluuebunny/crossref_metadata_2025 huggingface dataset:
Participatory planning in river catchments, an innovative toolkit tested in Southern Africa and North West England
Authors: Tippett J.
Published: May 2018

The European Union Water Framework Directive (WFD) offers an unparalleled opportunity for improving river basin management. Active participation is essential for its delivery. “End-of-pipe” solutions will not deliver the improvements needed to achieve its ambitious goals. This research tested DesignWays, a toolkit for participatory planning, as a mechanism for maximizing the long-term social and environmental benefits of such stakeholder and community participation. It examined the emerging role of “planning for sustainability” in the context of river catchments. Sustainable management of water requires integration, and recognition of interconnections between systems at different levels of scale. This is an endeavour in which systems thinking provides useful tools. The development of DesignWays was a conscious attempt to embed ‘new paradigm’ living systems metaphors into a practical planning tool. This paper begins with a description of DesignWays and its development in Southern Africa. An outline of the context of the action research in North-West England is followed by a description of the stages of the process, with highlights of the outcomes. This research had two major outcomes: a contribution to theory through an in-depth exploration of the theoretical basis of participatory, ecologically informed design; and a contribution to practice through investigating DesignWays' potential to meet key challenges of the WFD. This research points to the importance of understanding participatory planning as a societal process, aiming to make the process engaging and meaningful. It has pointed to the need to see participatory planning and education for sustainability as an integrated process. It demonstrated the benefits of an iterative process in which planning at the landscape level of scale informs, and is informed by, work at the site level. It has shown that an approach consistent with a living systems paradigm can contribute to the development of more integrated, ecologically sound plans.
Mineralisation of hazardous organic compounds in a sludge reed bed and sludge storage
Authors: Nielsen S.
Published: May 2018

Linear alkylbenzene sulphonates (LAS) and nonylphenolethoxylates (NPE) may be detrimental to the environment if spread in inappropriately large concentrations. Mineralisation of LAS and NPE in mesophilic digested sludge was observed during a 9-month monitoring programme where three separate treatment methods were investigated. Sludge was treated in a sludge reed bed under aerobic conditions, by storage in a container under anaerobic conditions, and by storage in a sludge pile turned over mechanically at intervals to improve the oxygen influx. Treatment in a sludge reed bed was shown to be effective. Mineralisation of 98% of LAS and 93% of NPE was observed. Only limited mineralisation occurred on the surface of the sludge stored in a container. A reduction of LAS and NPE of 90% and 43%, respectively, was observed in the sludge which was stored in a pile and frequently turned.
Catchment-scale fluorescence water quality determination
Authors: Baker A. , Inverarity R. , Ward D.
Published: May 2018

Chemical water quality determinants and river water fluorescence were determined on the River Tyne, northeast England. Statistically significant relationships between nitrate (r=0.87), phosphate (r=0.80), ammonia (r=0.70), biochemical oxygen demand (BOD) (r=0.85) and dissolved oxygen (r=−0.65) and tryptophan-like fluorescence intensity were observed. The strongest correlations are between tryptophan-like intensity and nitrate and phosphate, which in the Tyne catchment derive predominantly from point and diffuse source sewage inputs. The correlation between BOD and the tryptophan-like fluorescence intensity suggests that this fluorescence centre is related to the bioavailable or labile dissolved organic matter pool. The weakest correlations are observed between tryptophan-like fluorescence intensity and ammonia concentration and dissolved oxygen. The weaker correlation with ammonia is due to good ammonia treatment within the wastewater treatment plants within the catchment, and that with dissolved oxygen due to the natural aeration of the river such that this is not a good indicator of water quality. Mean annual tryptophan-like fluorescence intensity, measured by both bench and portable spectrometers, agrees well with the General Water Quality Assessment as determined by the England and Wales environmental regulators, the Environment Agency.
Quantification of dioxin in the sieved fraction of river sediment
Authors: Ozaki H. , Taniguchi S. , Takanami R. , Shimomukai N. , Hamasaki T. , Sugahara M. , Giri R.R.
Published: May 2018

Dioxin pollution of aquatic sediments has been one of the important environmental problems in Japan. Grain size distribution and organic constituents may play important roles in dioxins contents in sediments, which have not been well investigated. This paper aims to quantify dioxins (PCDDs/Fs and co-PCBs) in sieved surface sediment fractions obtained from Kizu and Sumiyoshi Rivers in Osaka, Japan. The samples were prepared and analyzed following the ‘Manual of the Survey and Measurement of Dioxins in Sediment’ (Environment Agency of Japan, 2000). The results showed that TEQ concentrations of dioxins increased with decreasing grain size in sediment fractions. Sediment fractions with less than 20μm grain size showed the highest dioxin contents. Dioxins with five and six chlorine atoms dominated other congeners in less than 20μm fractions. The dioxin TEQ concentrations increased with total organic carbon (TOC), total carbon (TC), ignition loss (IL), total sulphur and nitrogen contents in the sediment fractions. Thus, reporting dioxin contents in sediments without considering grain size distribution may be erroneous, and conventional sedimentation and separation techniques might not be useful for treating contaminated sediments. This information can be useful for effective remediation of dioxin-contaminated sediments.
Taxing for stormwater drainage systems
Authors: Nascimento N. , Cançado V. , Cabral J.R.
Published: May 2018

This article evaluates the possibility of creating a tax for urban drainage in order to make the system self-financing. Average costs of implementation and maintenance of the services were used to individualize the charges and definition of the tax. The conventional drainage system was evaluated along with a source control alternative, water detention in tanks on the lot. The magnitude of the values being charged varies in function of the impermeable surface and the density of the urban area. Preserving creeks in natural conditions and using source control approach, are all options with the advantages of lower investment and smaller burden for the users.
Enhancing phosphorus removal in constructed wetlands with ochre from mine drainage treatment
Authors: Heal K.V. , Dobbie K.E. , Bozika E. , McHaffie H. , Simpson A.E. , Smith K.A.
Published: May 2018

No single end-use has yet been identified that is capable of consuming the projected production of ochre (mainly iron (III) oxides) from mine drainage treatment. However, the high sorption capacity of ochre for phosphorus (up to 26 mg kg−1) means that it could be used in constructed wetlands to enhance phosphorus removal. Laboratory batch experiments showed that coarse-grained ochre removes 90% of all phosphorus forms from sewage effluent after 15 minutes of shaking. From a larger-scale experiment, it is estimated that constructed wetlands with an ochre substrate should remove phosphorus from sewage effluent for up to 200–300 years. The suitability of ochre for phosphorus removal is being investigated at the field scale in a wastewater constructed wetland (175 m2 area) in Berwickshire, UK. The hydraulic and treatment performance of the wetland were monitored for 15 months prior to installation at the inlet in November 2003 of a tank containing ∼1200 kg ochre. Results so far show that improved hydraulic design is required for ochre to increase the mean phosphorus removal efficiency of the system (27±28%), but potentially toxic metals (Al, Cd, Cr, Cu, Fe, Ni, Pb, Zn) have not been released from the ochre into the wetland outflow.
Wetland to pond treatment gradients
Authors: Kadlec R.H.
Published: May 2018

This paper presents information on the hydraulic efficiency of wetlands and ponds, and examines the differences and similarities between degrees of mixing, short-circuiting and dead zones. It reports the pollutant removal performance of over 50 wetlands and ponds over the range of macrophyte cover from 100% (densely vegetated wetlands) to 0% (ponds). Not surprisingly, there exist performance continua, characterized by a smooth transition from fully vegetated to unvegetated systems. Factors influencing the choice of ponds, wetlands or combinations are examined. Wetlands are more efficient, and can produce lower TSS. Both wetlands and ponds can provide BOD, FC and ammonia removal, with ponds being better choices at high loading rates.
Requirements and test methods for on site domestic wastewater treatment plants: the European standard (prEN 12566-3) compared to other international standards
Authors: Nonet S.
Published: May 2018

To ensure that domestic wastewater treatment plants run in an efficient and reliable way, certifications already exist while others will be implemented soon. To date, we have listed eight standards: four from European countries (Germany, Great Britain, The Netherlands and Norway), one project from the European Union, two from North America (USA and Quebec) and one from Australia and New Zealand together. The European procedure includes verification of structure stability, water tightness and treatment capacity at test centre (38 weeks). The American Standard sets minimal standards for materials, dimensioning, building and performances of the plants. It also highlights the information and minimum service that should be provided by the manufacturer and distributors. The review process relating to treatment performances shares major similarities with the EU project since both documents were elaborated almost simultaneously. Australia and New Zealand have adopted a series entitled On-site Domestic Wastewater Treatment Units made up of three parts. The third one integrates construction requirements and describes quite an interesting procedure to efficiently test the small plant: after approximately 13 weeks of testing (half the total duration), the aeration chamber (provided it exists) is filled with sludge from septic tanks to simulate its operation after several years. Overview of the treatment efficiency test procedures of the three main standards is given.
Effect of internal recycle rate on the high-strength nitrogen wastewater treatment in the combined UBF/MBR system
Authors: Ahn Y.T. , Kang S.T. , Chae S.R. , Lim J.L. , Lee S.H. , Shin H.S.
Published: May 2018

An anaerobic/aerobic system combining an anaerobic upflow-sludge bed filter (UBF) and an aerobic membrane bioreactor (MBR) was operated to enhance organic and nitrogen removal efficiency. The internal recycle rate, which is one of the most important operation factors that affects overall removal efficiency, was varied from 100% to 300% of the influent flow. Under these conditions, the overall removal efficiencies of organic and nitrogen and characteristics of membrane fouling in the combined system treating the synthetic wastewater including high concentration of organics and nutrients were studied. As a result, nitrogen removal efficiency was increased to 67% when the internal recycle rate was 300% of influent flow rate. As the internal recycle ratio increased from 100% to 200%, protein content decreased by 17% and carbohydrate content increased by 12%. However, there was no remarkable difference in total extracellular polymeric substances (EPS) content. At the high recycle rate of 300%, the surface charge of sludge was decreased while hydrophobicity (specific ultraviolet absorbance, SUVA) was increased. The differences in SUVA and surface charge were 11% and 1%, respectively. It is concluded that SUVA and EPS composition were important parameters affecting membrane fouling in the combined system.
Hydrogen sulphide production tests and the detection of groundwater faecal contamination by septic seepage
Authors: Roser D.J. , Ashbolt N. , Ho G. , Mathew K. , Nair J. , Ryken-Rapp D. , Toze S.
Published: May 2018

The ‘H2S test’ is being advanced for microbiological water quality testing where conventional coliform based methods are impractical or too expensive. It involves ambient temperature incubation of water samples with nutrient formulated to generate hydrogen sulphide when ‘faecal’ bacteria are present. Recently a WHO review identified several concerns including the limited number of comparative studies, formulation variability, and false positives and negatives. In response we have compared the H2S test's ability to detect and quantify faecal contamination in an aquifer impacted by septic tank leachfields with measurements obtained concurrently using conventional bacterial indicators, coliphages, faecal sterol biomarkers, Cryptosporidium and Giardia. Like these other analytes, H2S testing detected a contamination gradient ranging from high (septic liquid) to moderate (exfiltration zones), to background (e.g. domestic bores), corresponding to indicator removal + dilution by factors >106. Presence/absence tests could not distinguish between heavily and slightly contaminated waters, whereas multi-tube testing (e.g. 10 × 10 mL arrays) did. It was concluded that while the WHO review concerns are justified, the H2S test performance shows promise in sanitary survey work, can be improved by employing an mpn approach and has potential to aid in the protection of source water and identifying contaminated groundwater.
Equalization characteristics of an upflow sludge blanket – aerated biofilter (USB-AF) system
Authors: Jun H.-B. , Park S.-M. , Park J.-K. , Lee S.-H.
Published: May 2018

Equalization characteristics of the upflow sludge blanket – aerated bio-filter (USB-AF) were investigated with the fluctuated raw domestic sewage. Recycle of nitrified effluent from AF to USB triggered the equalization characteristics of the sludge blanket on both soluble and particulate organic matter. Increment of EPS in sludge blanket by nitrate recycle was detected and removal of turbidity and particulates increased at higher recycle ratios by bio-flocculation. Increased TCOD removal in the USB was due to both denitrification of recycled nitrate and entrapment of the particulate organic matter in sludge blanket. Capture of both soluble and particulate organic matter increased sludge blanket layer in the USB, which improved the reactor performances and reduced the organic load on the subsequent AF. Overall TCOD and SS removal efficiencies were about 98% and 96%, respectively in the USB-AF system. Turbidity in the USB effluent was about 44, 20 and 5.5 NTU, at recycle ratios of 0, 100 and 200%, respectively. Particle counts in the range 2–4 μm in the USB effluent were higher than those in influent without nitrate recycle, while particle counts in the range of 0.5–15 μm in the USB effluent decreased 70% at recycle ratio of 200%. The major constituent of EPS extracted from anaerobic sludge was protein and total EPS increased from 109.1 to 165.7 mg/g-VSS with nitrate recycle of 100%. Removal efficiency and concentration of T-N in the UBS-AF effluent was over 70% and below 16 mg/L, respectively.
Recent practices on wastewater reuse in Turkey
Authors: Tanik A. , Ekdal A. , Babuna F. Germirli , Orhon D.
Published: May 2018

Reuse of wastewater for irrigational purposes in agriculture has been a widely applied practice all around the world compared to such applications in industries. In most of the developing countries, high costs of wastewater treatment stimulate the direct reuse of raw or partly treated effluent in irrigation despite the socio-cultural objections in some countries regarding religious rituals towards consuming wastewater. In Turkey, reuse applications in agriculture have been in use by indirect application by means of withdrawing water from the downstream end of treatment plants. Such practices affected the deterioration of surface water resources due to the lack of water quality monitoring and control. However, more conscious and planned reuse activities in agriculture have recently started by the operation of urban wastewater treatment plants. Turkey does not face any severe water scarcity problems for the time being, but as the water resources show the signs of water quality deterioration it seems to be one of the priority issues in the near future. The industrial reuse activities are only at the research stage especially in industries consuming high amounts of water. In-plant control implementation is the preferred effort of minimizing water consumption in such industries. The current reuse activities are outlined in the article forming an example from a developing country.
Effectiveness of flow stabilization in small-scale wastewater treatment facilities
Authors: Nakajima J. , Tanaka R.
Published: May 2018

Household type Johkasous which have a flow stabilization function were surveyed on their performance. The water level, flow velocity and SS were measured after the maximum flow entering the anaerobic filter chamber with or without flow stabilization operation. In operation without the flow stabilization, the flow peak directly reached the biofiltration chamber and the flow rate kept at 1 cm/sec during 3–4 min in the connection baffle between the two anaerobic chambers. This suggested the possibility of sludge transfer from the first anaerobic chamber. Moreover the increase of SS in the second anaerobic chamber indicated sludge transfer from the second anaerobic chamber to the biofiltration chamber. In contrast, in operation with flow stabilization the relaxation of the water flow in the second anaerobic chamber and the biofilm chamber was verified. By the increase of the water level in the first anaerobic chamber, the flow stabilization performance was satisfactorily obtained. A model describing the change of the water level was developed and the calculated values and the measured value agreed well. The model will be useful in the design of the flow stabilization function.
2D numerical modelling of bed profile changes due to tsunami effects on near shore coasts: Kadikoy case study
Authors: Kabdasli M.S. , Kirca V.S. Ozgur , Aydingakko A.
Published: May 2018

This study was aimed at the investigation of tsunami effects on the seabed profile as these may be important for coastal structures, like sea outfalls or breakwaters. Tsunamis are well known with huge wave heights and destructive effects on the coastal region. A 2D numerical model was set using the software, COSMOS to calculate the cross-shore sediment transport and to evaluate profile changes in the coastal seabed. The study area is Kadikoy region, a densely populated industrial coastal area in South East Istanbul. The model was run for different kinds of tsunami waves. Not only the bed profile changes, but also the wave heights, breaker depths, peak wave bottom orbital velocities, wave set-up and cross-shore sediment transport rates were determined. The results indicated that, at a water depth around 40–50 m, some tsunamis were found to have a wave height of order of 15 m, which became about 5 m at a depth of 10 m. The wave set up near the coast was about 1.5–2 m. The results also implied that tsunami waves, with their destructive nature, could lead to dramatic vertical changes of the seabed.
Integrated modelling of conventional pollutants and organic contaminant fate in rivers: a microcosm study
Authors: Deksissa T. , Vanrolleghem P.A.
Published: May 2018

A new conceptual dynamic integrated model is presented which can be used to describe both conventional pollutants and organic contaminant fate in rivers. The model is designed to assess the short-term fate of organic contaminants in two compartments (bulk water and benthic sediment), taking into account the effect of nutrient dynamics. The biodegradation submodel was refined using a microcosm (artificial river) study and Linear Alkylbenzene Sulphonate (LAS) as an example. Based on data generated during the microcosm study, the model was calibrated and validated in both steady state (continuous constant load) and dynamic (pulse load) conditions. The results show that the simulated data set agrees well with the measured data set. Furthermore, thorough investigation of the model output sensitivity to the model inputs was made, and the results show that the fate of LAS is sensitive to the following model input variables: ammonia nitrogen, dissolved oxygen, microbial biomass and readily biodegradable soluble COD, and the model parameters mainly related to the biodegradation submodel. The model provides good understanding of the interaction between conventional pollutants and organic contaminants fate in rivers.
Setting-up a cost recovery system for the largest wastewater treatment plant in south-east Asia
Authors: Lønholdt J. , Jørgensen P. Elberg , O'Hearn D.
Published: May 2018

A tariff system has been set up for the largest wastewater treatment plant in South-East Asia, the Samut Prakarn Wastewater Treatment Plant south of Bangkok, which is currently under completion. Fully functional the plant will have a design capacity for 500,000m3 per day and will service a combined residential and industrial area with approximately 600,000 residents and 2,300 factories. The tariff system, which includes a tariff model, is based on water consumption and BOD load. As background for setting the tariffs a comprehensive monitoring system including an industrial permitting system has been developed. The paper presents the background and rationale for setting up the system as well as the objective, scope and content of the tariff system and the industrial permit system. Further, the feasibility of introducing cost recovery systems, which is widely accepted in developing economies on the conceptual level and to some extent implemented at the legal and regulatory level, but has yet to be implemented at large, is discussed.
Technical-economical evaluation of the operation of oxidation ditches
Authors: Ghermandi A. , Bixio D. , Thoeye C. , De Gueldre G.
Published: May 2018

The optimisation of the economic performance is a central aspect in the management of wastewater treatment plants. A model-based procedure was developed that could provide a clearly enunciated and concise way of reporting to the stakeholders on how well the assets are performing and can perform, separating the firm inefficiency from the effect of the treatment. The applied modelling method is conventional considering current modelling research practice, but very good from practical point of view in that it is applicable utilising existing plant data, i.e. without the use of additional measuring campaigns. This paper illustrates the validity of the developed procedures through the evaluation of the performance of oxidation ditches.
Some observations on the effects of accumulated benthic sludge on the behaviour of waste stabilisation ponds
Authors: Banks C.J. , Heaven S. , Zotova E.A.
Published: May 2018

The effect of accumulated bottom sludge on water column characteristics was studied in two pilot-scale ponds. Parameters measured were ammonia, nitrate, phosphate, COD, suspended solids, dissolved oxygen (DO), temperature and light intensity. The de-sludged pond showed a stronger correlation between DO, light intensity, nutrients and suspended solids with the controlling factor being availability of nitrogen. This was less apparent in the pond with sludge where nutrient levels were higher and more complex mechanisms controlled biomass concentration. Water column characteristics in the two ponds converged rapidly in 7–10 weeks, however, due to accumulation of fresh sludge.
Wastewater stabilisation ponds: sludge accumulation, technical and financial study on desludging and sludge disposal case studies in France
Authors: Picot B. , Sambuco J.P. , Brouillet J.L. , Riviere Y.
Published: May 2018

Waste stabilisation pond treatment was widely developed during the 1980s in France, where there are now over 3,000 plants. Desludging the ponds has now become essential. In 19 primary facultative ponds, in operation for 12–24 years, the net average sludge accumulation rate was 19 mm/yr. The average per capita accumulation rates ranged from 0.04–0.148 m3/person.year (mean of 0.08 m3/person.year). In primary facultative ponds the volume of sludge represented 15–39% of the total volume of the basin. A filling rate above 30% necessitates desludging. In France, a desludging interval of 15 years is recommended for primary facultative ponds. The cost evaluation of desludging and landspreading showed differences according to the desludging technique used. Desludging after emptying the water had an average cost of 38 €/m3 of sludge with 10% dry solid (range from 20 to 83 €/m3). Under-water desludging was 50% more expensive. Although desludging is carried out only after several years of operation, its cost must be allowed for in the annual operation and maintenance costs of the process. It can be estimated to be 3 €/person.year. Even with this additional cost, waste stabilisation pond treatment remains less expensive than other treatment processes.
Evaluation of sludge from pond system for treatment of piggery wastes
Authors: Zanotelli C.T. , Costa R.H.R. , Perdomo C.C.
Published: May 2018

Stabilization ponds used for the treatment of piggery wastes accumulate sludge over time, which is commonly used in agriculture. The objective of this study was to evaluate the agronomic potential of this kind of sludge. The samplings were collected in two different phases. The first in two anaerobic ponds (AP1 and AP2) and in one facultative pond with 5 transverse baffles and, the second in the same facultative pond with aeration. The removed sludge of AP1 and AP2 was characterized as rich sludge in volatile solids and with low stabilization, there was a great accumulation of the total phosphorus in the sludge of AP2. The facultative pond presented greater retention of nutrients in the sludge in relation to the anaerobic ponds. The annual accumulation of sludge was 13.3 cm/year in the AP1 and 6.70 cm/year in the AP2, while in the pond with aeration this was on the average of 0.5 cm/year, due to the aeration regime. The sludge can be used as a fertilizer in agriculture, if the chemical characteristics of the soil are taken into account so as to avoid the accumulation of nutrients and damage to plants.
Treatment of wastewater containing high phenol concentrations using stabilisation ponds enriched with activated sludge
Authors: Ramos M.S. , Dávila J.L. , Esparza F. , Thalasso F. , Alba J. , Guerrero A.L. , Avelar F.J.
Published: May 2018

Treatment of wastewater containing high phenol concentrations (up to 4,000 mg/l, 1,600 kg/ha.d) in laboratory-scale stabilisation ponds enriched with activated sludge was studied. Phenol was biodegraded efficiently, even when fed as the sole carbon source. At influent concentrations of 1,000, 1,300, 1,600, 1,900, 2,500, 3,000 and 4,000 mg/l of phenol (loading rates of 400, 520, 640, 760, 1,000, 1,200 and 1,600 kg phenol/ha.d), the phenol removal efficiencies were 92, 89, 81, 81, 76, 65 and 22%, respectively. At 4,000 mg/l of phenol, the enriched ponds were significantly inhibited. The maximum phenol removal rate observed was 780 kg/ha.d, which is 7.7 times higher than the maximum value reported for attached-growth waste stabilisation ponds. All along the experiments, the enriched ponds showed removal rates 1.8–20.5 times higher than the values observed in control pond (not enriched). The results suggest that enrichment is an effective method to increase xenobiotic removal rates of stabilisation ponds.
Comparison of maturation ponds and constructed wetlands as the final stage of an advanced pond system
Authors: Tanner C.C. , Craggs R.J. , Sukias J.P.S. , Park J.B.K.
Published: May 2018

The treatment performance of a maturation pond (MP), the typical final polishing stage of an Advanced Pond System (APS), is compared with that of a surface-flow constructed wetland (CW) over 19 months. Both received ∼67 mm d−1 of wastewater after passage through upstream stages of the APS. The MP, with greater sunlight exposure, had higher algal biomass (and associated suspended solids) than the CW, showed higher dissolved oxygen (DO) concentrations and greater diurnal variation in DO and pH. Neither polishing stages reduced nutrients markedly, with the CW exporting slightly more NH3-N and DRP, and less NO3-N than the MP. Disinfection was more efficient in the MP (geometric mean 1 log load removal, 12 MPN (100 ml)−1) compared to the CW (0.47 log load removal, 53 MPN (100 ml)−1). Incorporation of a final rock filter (28% of area) reduced median solids levels to <10 g m−3 in both the MP and CW. A hybrid between MPs and CWs with alternating zones of open-water (for enhanced disinfection and zooplankton grazing of algal solids) and wetland vegetation (promoting sedimentation and denitrification, and providing refugia for zooplankton) may provide more consistent effluent quality that either stage alone.
A dispersion based model for anaerobic digestion of solid cattle wastes in a stratified thermophilic accumulation system
Authors: El-Mashad H.M. , van Loon W.K.P. , Zeeman G. , Bot G.P.A. , Lettinga G.
Published: May 2018

A dynamic model has been developed to describe the anaerobic digestion of solid cattle waste in an accumulation system (AC). To calibrate the model an experiment was carried out at a lab-scale AC at 50 °C. The predicted methane production shows a very good agreement (i.e. R2=0.998) with the experimental data. However less agreement is evident for the intermediates. After model validation the model was applied to study the effect of different aspect ratios on the system performance. An optimum aspect ratio of 2–3 could be determined.
UASB treatment of liquid residues from grass bioraffination
Authors: Baier U. , Delavy P.
Published: May 2018

In 2001 the first green biorefinery started operation in Switzerland with a design load of 5,000 tons dm of grass per year and a combined output of fibres (0.4 tons per ton input), protein (160 t/t) and bioenergy (500 kWh/t). Bioenergy was produced in a 570 m3 UASB reactor which has been monitored intensively during its first year of operation. Anaerobic treatment of liquid residues with >80% degradation of organics was shown up to high f/m ratios and loading rates of 12–15 kg COD/m3 d and specific biogas production of 0.5–0.65 Nm3 of gas per kg of COD added. A mass flow analysis of solids and pellets leads to the conclusion, that due to a low sludge bed volume of only 16% of the reactor combined with a low actual organic loading of 1.5 kg COD/m3 d there was a restricted adsorption and a low degradation of substrate solids.
Multi-wavelength fluorometry for anaerobic digestion process monitoring
Authors: Morel E. , Santamaria K. , Perrier M. , Guiot S.R. , Tartakovsky B.
Published: May 2018

Applicability of multi-wavelength fluorometry for anaerobic digestion process monitoring was investigated in a 3.5 L upflow anaerobic sludge bed (UASB) lab-scale reactor. Both off-line and on-line monitoring of key process parameters was tested. Off-line emission spectra were measured at an angle of 90° to the excitation beam using a cuvette. On-line measurements were carried out using a fiber optic probe in the external recirculation line of the digester. Fluorescence spectra were correlated to available analytical measurements to obtain partial least square regression models. An independent set of measurements was used to validate the regression models. Model estimations showed reasonable agreement with analytical measurements with multiple determination coefficients (R2) between 0.6 and 0.95. Results showed that off-line fluorescence measurements can be used for fast estimation of anaerobic digestor effluent quality. At the same time, the on-line implementation of multi-wavelength fluorescence measurements can be used for real-time process monitoring and, potentially, for on-line process control.
Effect of inoculum and sludge concentration on viscosity evolution of anaerobic granular sludges
Authors: Pevere A. , Guibaud G. , van Hullebusch E. , Lens P. , Baudu M.
Published: May 2018

The rheological behaviour of granular sludges (diameter 20–315 μm) originating from different anaerobic reactors was carried out using rotation tests. The sieved granular sludges suspensions display a non-Newtonian rheological behaviour and the limit viscosity was therefore used as a rheological parameter. The values obtained, which depend on the shear rate used, were strongly influenced by the total suspended solids (TSS) content of granular sludge and an exponential relation was found between the TSS and the rheological parameter limit viscosity. The increase of viscosity as a function of TSS content of the granular sludge as well as the increase of granule size underlines the importance of the interaction between granules in the evolution of this rheological parameter. Significant differences in granular sludge limit viscosity were found for granular sludge of different origins. All measurements performed with 10 g.l−1 TSS granular sludge indicate the ability of the chosen rheological parameter to describe different granular sludge quality.
Model analysis for nitrogen effluent from upland field constructed with under-drain
Authors: Shiratani E. , Yoshinaga I. , Singh R.K.
Published: May 2018

A mathematical model to estimate nitrogen (N) effluent from an upland field cultivated with barley, where under-drain pipes were installed 60 cm below the field surface, was developed and N effluents for several rainfall patterns during the cultivation period were analysed. The model is composed of the water drainage model and N cycle model. The water drainage model is made up of Sugawara's tank model in which the field is divided into two soil types, permeable soil and impermeable soil, and macro pore. The N cycle model can calculate the N reactions including nitrification, denitrification, mineralization, immobilization, urea hydrolysis and N transportation in the field. By using this model, N effluents caused by rainfall were analysed and characteristics of N effluent were clarified. The under drainages caused by heavy rains which occur around 60 days after fertilization contribute greatly to the amount of N effluent load during a cultivation period. Also, split application of fertilizer is not effective for the reduction of N effluents under any cultivation conditions, especially in winter crops. A large quantity of N effuses out of the field because the major portion of rainfall in a cultivation period occurs in the latter half of the period.
Management of regional German river catchments (REGFLUD) impact of nitrogen reduction measures on the nitrogen load in the River Ems and the River Rhine
Authors: Kunkel R. , Bogena H. , Goemann H. , Kreins P. , Wendland F.
Published: May 2018

The REGFLUD-project, commissioned by Germany's Federal Research Ministry (BMBF), addresses the problem of reducing diffuse pollution from agricultural production. The objective of the project is the development and application of multi-criteria scientific methods, which are able to predict diffuse pollution in river basins subject to economic feasibility and social acceptability. The selected river basins (Ems and Rhine basins) cover a variety of landscape units with different hydrological, hydrogeological and socio-economic characteristics. This paper focuses on the analysis of the effects of certain policy measures to reduce diffuse pollution by nitrogen. For this purpose a model system consisting of an agricultural sector model, a water balance model and a residence time/denitrification model was developed and applied. First results indicate a wide range of annual nitrogen surpluses for the rural areas between less than 10 kg N/ha up to 200 kg N/ha or more depending on the type and intensity of farming. Compared to the level of nitrogen surpluses the level of nitrogen inputs into the surface waters is relatively moderate because of degradation processes during transport in soil and groundwater. Policy impact analysis for a nitrogen tax and a limitation of the livestock density stress the importance of regionally tailored measures.
Propagation of uncertainty in diffuse pollution into water quality predictions: application to the River Dender in Flanders, Belgium
Authors: Vandenberghe V. , van Griensven A. , Bauwens W. , Vanrolleghem P.A.
Published: May 2018

The uncertainty of water quality predictions caused by uncertainty in the inputs related to emissions of diffuse pollution is analysed. An uncertainty analysis of the effects of diffuse pollution is essential to compare the cost and benefits of measures to lower those emissions. We focus on diffuse nitrate pollution due to fertiliser use. Using an efficient Monte Carlo method and Latin Hypercube sampling, the contribution to the overall uncertainty by each of the inputs is calculated. The modelling environment is ESWAT, an extension of SWAT, which allows for integral modelling of the water quantity and quality processes in river basins. The diffuse pollution sources are assessed by considering crop and soil processes. The crop simulations include growth, uptake of water and nutrients and several land management practices. The in-stream water quality model is based on QUAL2E. The spatial variability of the terrain strongly affects the non-point source pollution processes. The methodology is applied to the Dender basin in Belgium. Eight inputs have significant influence on the time that the nitrate content in the river is higher than 3 mg/l. The uncertainty analysis indicated wide uncertainty bounds (95% percentile bounds differ up to ±50% from the average NO3 predictions).
Impact of RO-desalted water on distribution water qualities
Authors: Taylor J. , Dietz J. , Randall A. , Hong S.
Published: May 2018

A large-scale pilot distribution study was conducted to investigate the impacts of blending different source waters on distribution water qualities, with an emphasis on metal release (i.e. corrosion). The principal source waters investigated were conventionally treated ground water (G1), surface water processed by enhanced treatment (S1), and desalted seawater by reverse osmosis membranes (RO). Due to the nature of raw water quality and associated treatment processes, G1 water had high alkalinity, while S1 and RO sources were characterized as high sulfate and high chloride waters, respectively. The blending ratio of different treated waters determined the quality of finished waters. Iron release from aged cast iron pipes increased significantly when exposed to RO and SI waters: that is, the greater iron release was experienced with alkalinity reduced below the background of G1 water. Copper release to drinking water, however, increased with increasing alkalinity and decreasing pH. Lead release, on the other hand, increased with increasing chloride and decreasing sulfate. The effect of pH and alkalinity on lead release was not clearly observed from pilot blending study. The flat and compact corrosion scales observed for lead surface exposed to S1 water may be attributable to lead concentration less than that of RO water blends.
Removal of endocrine disruptors using homogeneous metal catalyst combined with nanofiltration membrane
Authors: Kim J.H. , Kwon H. , Lee S. , Lee C.H.
Published: May 2018

Chemicals that are known or suspected of being endocrine disrupting chemicals (EDCs) have received increased attention over the past decade for their potential presence in drinking water sources. This study focuses on the development of a hybrid system that combines the advantages of nanofiltration (NF) and homogeneous catalytic oxidation, which include compactness, operational facilitation, high treatment efficiency, and selective reaction capability. Iron(III)-tetrasulfophthalocyanine (Fe-TsPc) was employed as a homogeneous metal catalyst to degrade bisphenol-A (BPA), a representative EDC. The treatment efficiency of BPA as well as operational characteristics of the hybrid system was investigated to examine the applicability of this technique to decrease the concentration of EDCs in drinking water. Fe-TsPc homogeneous catalyst revealed a remarkable activity in degrading BPA under acidic condition. The high rejection of Fe-TsPc catalyst in the feed stream by the membrane for its large molecular weight (976 Da) and functional group (SO3− X4) allowed the continuous use of the catalyst for BPA oxidation reaction. The NF with Fe-TsPc/H2O2 hybrid system turned out to have higher BPA treatment efficiency comparing with the NF-only system since the hybrid system reduced BPA concentration in the feed stream by catalytic destruction of BPA as well as it mitigated concentration polarization on the surface of the membrane.
Effect of organic loading rate on a wastewater treatment process combining moving bed biofilm and membrane reactors
Authors: Melin E. , Leiknes T. , Helness H. , Rasmussen V. , Ødegaard H.
Published: May 2018

The effect of moving bed biofilm reactor (MBBR) loading rate on membrane fouling rate was studied in two parallel units combining MBBR and membrane reactor. Hollow fiber membranes with molecular weight cut-off of 30 kD were used. The HRTs of the MBBRs varied from 45 min to 4 h and the COD loading rates ranged from 4.1 to 26.6 g COD m−2 d−1. The trans-membrane pressure (TMP) was very sensitive to fluxes for the used membranes and the experiments were carried out at relatively low fluxes (3.3–5.6 l m−2 h−1). Beside the test with the highest flux, there were no consistent differences in fouling rate between the low- and high-rate reactors. Also, the removal efficiencies were quite similar in both systems. The average COD removal efficiencies in the total process were 87% at 3–4 h HRT and 83% at 0.75–1 h HRT. At high loading rates, there was a shift in particle size distribution towards smaller particles in the MBBR effluents. However, 79–81% of the COD was in particles that were separated by membranes, explaining the relatively small differences in the removal efficiencies at different loading rates. The COD fractionation also indicated that the choice of membrane pore size within the range of 30 kD to 0.1 μm has very small effect on the COD removal in the MBBR/membrane process, especially with low-rate MBBRs.
Evaluation of MBR effluent characteristics for reuse purposes
Authors: Oota S. , Murakami T. , Takemura K. , Noto K.
Published: May 2018

One of the advantages of MBR is its excellent effluent quality, which is suitable for a wide range of reuse purposes. We investigated the characteristics of MBR effluent and evaluated them based on the Japanese guideline for the reuse of treated wastewater. As the result, MBR effluent showed qualitative characteristics that satisfy the requirement except chromaticity for recreational purpose. Further treatment, such as by ozone or activated carbon, will be required to remove the remaining color. MBR shows high removal efficiency of bacteria and other hazardous microorganisms such as Cryptosporidium.

We investigated the removal efficiency of virus by MBR using coliphage as an alternative index. The results showed that high removal efficiency for coliphage could be obtained by MBR. The removal mechanism appears to be that coliphage are attached to the activated sludge and thus rejected by the membrane together with activated sludge particles. With regard to the endocrine disrupters, no significant differences were observed between MBR and CAS in the removal of main endocrine disrupters.
Biodegradation of phenol at low temperature using two-phase partitioning bioreactors
Authors: Guieysse B. , Autem Y. , Soares A.
Published: May 2018

Two-phase partitioning bioreactors offer many advantages for the removal of toxic pollutants. In particular, such systems can be loaded with very large quantities of pollutants without risks of microbial inhibition, they are self-regulated and they prevent the risks of hazardous pollutant volatilisation during aerobic treatment. However, their potential has never been tested at low temperatures. Phenol biodegradation by a cold adapted Pseudomonas strain was therefore tested at 14 or 4°C using 2-undecanone, diethyl sebacate or 2-decanone as organic phases in a two-phase partitioning bioreactor. The three solvents were biocompatible at 14°C but evidence was found that diethyl sebacate was biodegraded by the bacteria and this solvent was not tested further. Although only 2-decanone was suitable at 4°C, phenol biodegradation was more efficient in 2-undecanone at 14°C, reaching a maximum volumetric rate (based on the volume of aqueous phase) of approximately 1.94g/L·day after 47h of cultivation. In 2-decanone at 14°C, evidence was found that phenol degradation was limited by the release of biosurfactants, which increased the solubility and toxicity of the solvent in the aqueous phase inhibiting microbial activity. This study therefore shows that pollutant removal at low temperature is feasible but that the production of biosurfactants can have a negative impact on the process and must be taken into consideration when selecting the organic solvent. Future work should therefore focus on the selection of solvents suitable for use at temperatures below 14°C.
High-rate wastewater treatment combining a moving bed biofilm reactor and enhanced particle separation
Authors: Helness H. , Melin E. , Ulgenes Y. , Järvinen P. , Rasmussen V. , Ødegaard H.
Published: May 2018

Many cities around the world are looking for compact wastewater treatment alternatives since space for treatment plants is becoming scarce. In this paper development of a new compact, high-rate treatment concept with results from experiments in lab-scale and pilot-scale are presented. The idea behind the treatment concept is that coagulation/floc separation may be used to separate suspended and colloidal matter (resulting in >70% organic matter removal in normal wastewater) while a high-rate biofilm process (based on Moving Bed™ biofilm reactors) may be used for removing low molecular weight, easily biodegradable, soluble organic matter. By using flotation for floc/biomass separation, the total residence time for a plant according to this concept will normally be <1 hour. A cationic polymer combined with iron is used as coagulant at low dosages (i.e. 1–2mg polymer/l, 5–10mg Fe/l) resulting in low sludge production (compared to conventional chemical treatment) and sufficient P-removal.
The discharged excess sludge treated by Oligochaeta
Authors: Wei Y. , Liu J.
Published: May 2018

To overcome unstable worm growth, a new worm-reactor was developed for oligochaete growth. The bench scale of this worm-reactor was used to treat the discharged excess sludge from a pilot activated sludge system, and experiments were carried out to investigate the sludge reduction induced by Oligochaeta. Due to difficult getting free-swimming worms such as Aeolosoma hemprichicii and Nais elinguis, Tubifex tubifex was thus selected and inoculated in Reactor 1 at the start-up phase except the control reactor (Reactor 2). Tubifex occurred in Reactor 1 throughout the operation period after its inoculation, and mainly attached on the carriers and aggregated on the bottom of the worm-reactor. Free-swimming worms such as Aeolosoma hemprichicii, Nais elinguis, and Aulophorus furcatus were found in both reactors since the 35th day. Microscopic investigation showed that these free-swimming worms naturally produced in the pilot activated sludge system, and entered into both reactors along the discharged sludge. Results clearly showed that the average sludge reduction in Reactor 1 was 59%, much higher than that in the control. The characteristics of sludge settling was improved by worm growth, but was not too much. High ammonia nitrogen concentration in influent sludge was toxic to worms, and then inhibited worm growth. Both the total inorganic nitrogen and phosphorus releases into effluent sludge were observed in Reactor 1, but such increases were not heavy.