bluuebunny/crossref_metadata_2025 huggingface dataset:
Post-treatment of UASB effluent in an expanded granular sludge bed reactor type using flocculent sludge
Authors: Kato M.T. , Florencio L. , Arantes R.F.M.
Published: May 2018

The performance of an EGSB (expanded granular sludge bed) reactor type using flocculent sludge was evaluated for the post-treatment of effluent from UASB reactor treating domestic sewage. A pilot-scale 157.5-L EGSB reactor was monitored during a 331-day period. The original concept of the EGSB reactor was based on granular sludge use and by applying of high upflow liquid velocities (Vup). However, even using flocculent sludge from a UASB full-scale (Mangueira Plant, Recife, Brazil), good mixing conditions and high retention of biomass were achieved. By applying a 4-h hydraulic retention time and Vup values up to 3.75 m/h, effluent chemical oxygen demand concentrations in the EGSB were below 87 mg/L and 55 mg/L, for total and filtered samples, respectively. Total suspended solid (TSS) concentrations in the effluent were below 32 mg/L. Good performance and stable reactor operation during the whole experimental period were observed. Therefore, the EGSB reactor type using flocculent sludge can also be used for post-treatment of very dilute anaerobic effluent from reactors treating domestic sewage.
A membrane assisted hybrid bioreactor for the post treatment of an anaerobic effluent from a fish canning factory
Authors: Oyanedel V. , Garrido J.M. , Lema J.M. , Méndez R.
Published: May 2018

An innovative membrane assisted hybrid bioreactor was used to treat a mixture of two streams produced in a fish canning factory: a highly loaded stream that had previously been treated in an anaerobic contact reactor, and a second stream with a relatively low COD and N concentration. Experiments were carried out during two experimental stages: an aerobic stage, which is focused in the study on the aerobic oxidation of ammonia and COD and a nitrification-denitrification stage in which the study was mainly focused on the removal of nitrogen. Results of the aerobic period pointed out that it was feasible to achieve ammonia and COD removals of around 99% at OLR of 6.5 kg COD/m3·d and NLR of 1.8 kg N-NH4+/m3·d. Specific nitrifying activities of up to 0.78 g N-NH4+/g protein·d and 0.25 g N-NH4+/g VSS·d, were recorded for the attached and suspended biomass, respectively. Around 50-60% of the nitrifying capacity of the reactor was a result of the nitrifying capacity of the biofilm. During the nitrification-denitrification stage 76% of nitrogen removal was attained at an NLR of 0.8 kg N-NH4+/m3·d. The biofilm nitrifying activity was not affected by the operating conditions of the system, as a result of the preferential consumption of COD by suspended biomass in the reactor. Thus, the combination of a hybrid system, with both suspended and attached biomass, and an ultrafiltration membrane module might be an alternative for treating wastewaters in compact biological systems. The intrinsic characteristics of the system made it feasible to operate at high OLR without problems related with the settling properties of the sludge or the drop in the nitrogen conversion. There were no solids in the effluent as a result of the use of the membrane filtration module.
Groyne fields – sink and source functions of “flow-reduced zones” for water content in the River Elbe (Germany)
Authors: Ockenfeld K. , Guhr H.
Published: May 2018

The role of man-made “flow-reduced zones” as a sink or a source of water content is unknown for the River Elbe, Germany. We measured and compared: a) the concentration of suspended matter at the inflow and the outflow of one special groyne field (“UFZ groyne field”) weekly for a period of two years; and b) the intensity of oxygen metabolism within several groyne fields and the main stream during a Lagrangian survey. Under discharge conditions near or below mean water, we found a significant reduction of suspended particulate matter and particle bound nutrients in the “UFZ groyne field”. In contrast, concentrations of most soluble water contents and chlorophyll a did not significantly change between in- and outflow. During the Lagrangian survey, pelagic production and respiration rates developed nearly identically in both the main stream and the adjacent groyne fields but oxygen time curves showed higher amplitudes for the groyne fields compared to the river. This higher net-oxygen production in the groyne fields is due to reduced water depth and reduced stream velocity. It enhances the concentration of oxygen in the main stream. The contrary results show the coexistence of both sink and source functions of “flow-reduced zones” in rivers.
Water quality in sugar catchments of Queensland
Authors: Rayment G.E.
Published: May 2018

Water quality condition and trend are important indicators of the impact of land use on the environment, as degraded water quality causes unwelcome changes to ecosystem composition and health. These concerns extend to the sea, where discharges of nutrients, sediments and toxicants above natural levels are unwelcome, particularly when they drain to the Great Barrier Reef World Heritage Area and other coastal waters of Queensland. Sugarcane is grown in 26 major river catchments in Queensland, most in environmentally sensitive areas. This puts pressure on the Queensland Sugar Industry to manage the land in ways that have minimum adverse off-site impacts. Sugar researchers including CRC Sugar have been associated with water quality studies in North Queensland. These include investigations and reviews to assess the role of groundwater as a pathway for nitrate loss from canelands in the Herbert Catchment, to find causes of oxygen depletion in water (including irrigation runoff) from Ingham to Mackay, to use residues of superseded pesticides as indicators of sediment loss to the sea, and to assemble information on water quality pressure and status in sugar catchments. Key findings, plus information on input pressures are described in this paper, and areas of concern and opportunities discussed.
Measuring the total value of a river cleanup
Authors: Alam M.K. , Marinova D.
Published: May 2018

The paper estimates the total value for the community of the cleanup of the Buriganga River. Dhaka, the capital of Bangladesh, was developed on the bank of the Buriganga River in the early 1600s. The river is now near dead mainly due to human interventions. The paper develops a hypothetical cleanup programme to improve the water quality, which will help the overall environment in and around the river. The value of this programme is estimated within the framework of total economic value; non-marketed benefits are measured through a contingent valuation survey and marketed benefits are estimated using market and shadow prices. The findings of the survey suggest that not only are a significant proportion of the residents willing to pay for the cleanup programme, but many are also willing to contribute in non-monetary ways (mainly their time). When the latter contribution is monetised, it represents 60% of the total value for the non-marketed benefits. The marketed benefits are estimated to represent 58% of the overall value of the cleanup programme (US$18.6 million/year). A failure to account for all benefits could lead to a gross underestimation of the desirability of providing public funding for the cleanup of dying rivers.
Who owns AustraliaÕs water – elements of an effective regulatory model
Authors: McKay J.
Published: May 2018

This paper identifies and describes a number of global trends in regulatory theory and legal scholarship. It points out the huge level of complexity demanded by globalisation and the unfortunate complication of this is that there is legal indeterminacy. The legal indeterminacy springs from the desire to amend and alter existing models. That has been the thrust of the Council of Australian Governments changes to adapt and add huge amounts of complexity to a flawed system. This paper argues that an effective water regulatory model requires a fundamental re-examination of the concept of water ownership and a capturing by the State of the right to allocate rainfall. This foundation is effective and the way forward to deal with the key issues in this transition phase. The second key element to an effective regulatory model is the concept of performance-based assessment. This requires information and schemes to be set up to work out ways to monitor and evaluate the performance of the utility on selected criteria. For Australia at present there is a dire lack of agreed criteria on these key issues and these have the potential to pull apart the whole process. The key issues are indigenous rights, governance issues, public participation, alteration of pre-existing rights and incorporation of environmental requirements.
Long term effects of temperature and substrate level on BNR with an external nitrification reactor
Authors: Ha J.S. , Choi E.
Published: May 2018

This study was conducted with a BNR (biological nutrient removal) process with an external nitrification and switching arrangement of anoxic and oxic stages. It was observed that the SPRR (specific phosphorus release rate) and SDNR(specific denitrification rate) were greatly affected by the organic loads, and SDNR had a higher temperature effect than other kinetic rates including nitrification. It was further observed that the stoichiometric values like PHA (poly hydroxyalkanoate) stored for P release and PHA consumed for P uptake also varied. Variations of % Px(phosphorus content) and PHA as intracellular matter suggest the PAOs were more active at lower temperatures with this process configuration, where more than 70% of NH4-N and phosphorus were removed at temperatures below 10°.
Laboratory scale and pilot plant study on treatment of toxic wastewater from the petrochemical industry by UASB reactors
Authors: Stergar V. , Zagorc-Končan J. , Zgajnar-Gotvanj A.
Published: May 2018

This research concentrates on the development of an integrated approach to evaluate the possibility of treating very concentrated (COD = 15–20 g/l) and toxic wastewater (nitro-organic effluent) from the petrochemical industry in UASB reactors. A newly developed method utilising a modified Micro-Oxymax respirometer was used to (1) evaluate the inhibitory effects of varying concentrations of nitro-organic effluent on anaerobic granular sludge and (2) to make the proposal of operational parameters for the start up of the continuous process. Subsequently, the continuous tests were undertaken using laboratory scale upflow anaerobic sludge bed reactors to test gradual adaptation of anaerobic biomass to nitro-organic effluent. Practical application of the experimental results of the laboratory-scale continuous tests was evaluated by running the UASB pilot plant. Acceptable COD removal efficiencies were obtained when nitro-organic effluent was diluted with a readily biodegradable substrate up to 80 vol % of nitro-organic effluent in the inlet. The COD removal was 90% and the methane production rate was 4.5 l/d. Wastewater was detoxified and no acute toxicity of the treated wastewater to the anaerobic biomass was detected. This research indicates that anaerobic digestion of the undiluted nitro-organic effluent was not feasible. However, it is possible to blend the nitro-organic effluent with another effluent stream and co-treat these effluents.
Effects of ferric ion on bioleaching of heavy metals from contaminated sediment
Authors: Chen S.Y. , Lin J.G. , Lee C.Y.
Published: May 2018

Bioleaching is one of the promising procedures for removal of heavy metals from contaminated sediments. The advantages of this biotechnology are that it is easy, efficient, less costly and friendly to the environment. However, the principal disadvantage of this process is its slow kinetics in metal solubilization, which may limit practical application of the bioleaching process. In order to enhance the rate and efficiency of metal solubilization, the ferric ion was used as a catalytic agent in the bioleaching process. It was found that the sediment pH apparently decreased in the bioleaching after addition of ferric ion. The metal solubilization increased quickly after the addition of ferric ion. The rate of metal solubilization was enhanced by the addition of ferric ion, especially for Cr and Pb. An increase in the amount of ferric ion added increased the final efficiency of metal solubilization. The highest final efficiency of metal solubilization was obtained in the bioleaching with 1 g/L of ferric ion. Besides, the growth of sulfur-oxidizing bacteria was not affected by addition of ferric ion in the bioleaching. It was concluded that the kinetics of metal solubilization were enhanced by addition of ferric ion in the bioleaching process.
Application of a membrane bioreactor system for opto-electronic industrial wastewater treatment - a pilot study
Authors: Chen T.K. , Chen J.N. , Ni C.H. , Lin G.T. , Chang C.Y.
Published: May 2018

The membrane bioreactor (MBR) system has become more and more attractive in the field of wastewater treatment. It is particularly attractive in situations where long solids retention times are required, such as nitrifying bacteria, and physical retention is critical to achieving more efficiency for biological degradation of pollutants. Although it is a new technology, the MBR process has been applied to industrial wastewater treatment for only the past decade. The opto-electronic industry, developed very fast over the past decade in the world, is a high technological manufacturing industry. The treatment of the opto-electronic industrial wastewater containing a significant quantity of organic nitrogen compounds, with a ratio over 95% in organic nitrogen (Org-N) to total nitrogen (T-N), is very difficult to meet the discharge limits.

The purpose of this research is mainly to discuss the treatment capacity of high-strength organic nitrogen wastewater, and to investigate the capabilities of the MBR process. A 2 m3/day capacity MBR pilot plant consisting of anoxic and aerobic tanks and a membrane bioreactor was installed for evaluation. The operation was continued for 130 days. Over the whole experimental period, a satisfactory organic removal performance was achieved. The COD could be removed with an average of over 94.5%. For TOC and BOD5, the average removal efficiencies were 96.3 and 97.6%, respectively. The nitrification and denitrification were also successfully achieved. The effluent did not contain any suspended solids. Only a small concentration of ammonia nitrogen was found in the effluent. The stable effluent quality and satisfactory removal performance mentioned above were ensured by the efficient interception performance of the membrane device incorporated within the biological reactor. The MBR system shows promise as a means of treating very high organic nitrogen wastewater without dilution. The effluent of TKN, NOx-N and COD can fall below 20 mg/L, 30 mg/L and 50 mg/L.
Production of biopesticides using wastewater sludge as a raw material - effect of process parameters
Authors: Tirado Montiel M.L. , Tyagi R.D. , Valero J.R. , Surampalli R.Y.
Published: May 2018

Production of Bacillus thuringiensis (Bt) based biopesticide was studied using hydrolysed or raw wastewater sludge as a raw material. The sludge hydrolysis was carried out at different pH (2, 4 and 6). The sludge after hydrolysis was sterilised at 121°C for 30 minutes. The effect of temperature, pH and agitation speed on growth and toxin production was also investigated. The pH in the shake flask was controlled by adding 0.1 M TRIS buffer. The progress of the biopesticide production process was monitored by measuring viable cell count (VC), spore count (SC) and entomotoxicity (Tx). The entomotoxicity was measured against spruce budworm. Control of pH substantially increased the entomotoxicity of the final product. Increased agitation speed resulted in higher VC, SC and Tx values.
Control of Cryptosporidium with wastewater treatment to prevent its proliferation in the water cycle
Authors: Suwa M. , Suzuki Y.
Published: May 2018

The outbreak of Cryptosporidiosis in 1996 in Japan is thought to have been enlarged by the proliferation of Cryptosporidium in the water cycle from wastewater to drinking water through the river system. From this experience, the wastewater system must have functions to remove Cryptosporidium oocysts effectively. Efficiencies of wastewater treatment processes to remove oocysts were investigated using pilot plants receiving municipal wastewater. An activated sludge process and a following sand filter showed removal efficiencies of 2 log and 0.5 log, respectively. Poly-aluminium chloride dosage improved the efficiencies by 3 log for the activated sludge process and by 2 log for the sand filter. Chemical precipitation of raw wastewater with poly-aluminium chloride could achieve 1 to 3 log removal according on the coagulant concentration.
The effect of chlorination of estrogenic chemicals on the level of serum vitellogenin of Japanese Medaka (oryzias latipes)
Authors: Tabata A. , Miyamoto N. , Ohnishi Y. , Itoh M. , Yamada T. , Kamei T. , Magara Y.
Published: May 2018

Mature male medaka were continually exposed to four chemicals, p-n-nonylphenol (p-n-NP), p-nonylphenol (p-NP), bisphenol-A (BPA) and 17b-estradiol (E2) to evaluate their estrogenic activities in the laboratory. In order to understand the effect of the chlorination that is applied widely in water and waste-water treatment, the above chemicals were chlorinated and then exposed to mature male medaka. Furthermore, in the case of vitellogenin, a is a female specific protein induced by the exposure to test waters containing the above chemicals after 5 weeks, medaka was returned to uncontaminated tap water to determine whether male medaka have a self recovery function from the effect of estrogenic chemicals.

Much greater vitellogenin compared to the background levels were induced in the male medaka by separate exposure to 100 μg/L of p-NP, 1,000 μg/L of BPA and 0.05 μg/L of E2. The levels of vitellogenin increased with increasing exposure periods. The relative potencies of these chemicals descended in the order of E2 >> p-NP> BPA.

Vitellogenin levels inducible by these chemicals were drastically reduced as a result of the chlorination for 24 hours. However, a moderate increase in hepatocyte somatic index (HSI) meant the hepatic fatness was observed as a result of chlorination. It is not clear at this stage whether or not the formation of chlorination by-products is responsible for this moderate increase in HSI.

The vitellogenin concentration of male medaka exposed to chemicals for 5 weeks decreased gradually after return to the uncontaminated water. However, the vitellogenin concentration did not return to the initial normal levels even after 5 weeks.

A clear relationship between the serum vitellogenin concentration and the hepatic vitellogenin concentration was also found. Since quantitative analytical procedures for hepatic vitellogenin are easier than those of the serum vitellogenin, measuring the estrogenic effect using the measurement of vitellogenin in liver is recommended.
Road salts in urban stormwater: an emerging issue in stormwater management in cold climates
Authors: Marsalek J.
Published: May 2018

Potential impacts of road salting on the environment have increased by the introduction of certain stormwater management practices. Specific impacts are discussed for four such practices, infiltration facilities, oil and grit separators, stormwater ponds and constructed wetlands. The main concerns about the hazards of chloride-laden stormwater discharges include contamination of groundwater, leaching out of trace metals, densimetric stratification and poor vertical mixing in ponds, direct and indirect toxic effects, benthic drift and reduced biodiversity. The associated environmental risks need to be reduced by chloride source controls, and prevention of excessive chloride accumulations by appropriate design and operation of stormwater facilities in winter months.
Correlations of extractable heavy metals with organic matters in contaminated river sediments
Authors: Tsai L.-J. , Ho S.-T. , Yu K.-C.
Published: May 2018

In southern Taiwan, almost all the main rivers have been contaminated by anthropogenic heavy metals and organic matters. The main pollution sources include agricultural, industrial, and domestic activities. River sediments potentially have large capacities to accumulate heavy metals and organic matters when the river water flows through it. The sediments sampled from high contaminated river (the Yenshui River) and moderately contaminated rivers (the Tsengwen, Chishui, Potzu, and Peikang Rivers) were used to realize correlations between each kind of aqua regia extractable heavy metals (Co, Cr, Cu, Zn, Ni, Pb, Mn, and Fe) and organic matters in vertical sediment cores. Organic matters and aqua regia extractable heavy metal concentrations, analyzed by strong acid-digested extraction, were determined in vertical profile segments from downstream sediments of the five rivers. Sum of six aqua regia extractable heavy metals (Co, Cr, Cu, Zn, Ni, and Pb) were below 3,000 mg/kg in sediments of the Yenshui River, and below 500 mg/kg in the other four rivers' sediments. Strongly positive correlations (r = 0.83-0.95) between each kind of aqua regia extractable heavy metals and organic matters (concentration range between 0.6 to 3.8%) were observed in sediments of the Yenshui River. The slopes of the linear regressive lines approximated the average metal complexation ratios with organic matters in the sediments. In sediments of the other four rivers, smaller positive correlation coefficients between aqua regia extractable heavy metals and organic matters (below 2.6%) were observed. The complexation ratios derived from the four moderately polluted river sediments were smaller than those derived from the highly contaminated river sediments, indicating that the importance of organic matters in the accumulation of heavy metals in river sediments.
Biodegradation of MTBE and BTEX in an aerobic fluidized bed reactor
Authors: Pruden A. , Sedran M. , Suidan M. , Venosa A.
Published: May 2018

An aerobic fluidized bed reactor (FBR) was operated for the removal of methyl tert-butyl ether (MTBE) and benzene, toluene, ethylbenzene, and p-xylene (BTEX) from water. The reactor was seeded with a mixed culture adapted to MTBE. Granular activated carbon (GAC) was used as the biological attachment medium. Influent MTBE to the reactor was 7.8 mg/L MTBE, with a flow rate of 22.7 L/day, and an empty bed contact time of 1 hour. The acclimation period required was relatively short, about 30 days before reaching an average stable effluent concentration of 18.5 ± 10 μg/L. BTEX was introduced to the feed at an equivalent chemical oxygen demand (COD) as the MTBE at day 225 and was biodegraded spontaneously with no apparent acclimation period required. The average influent of each of the four BTEX compounds was about 2 mg/L, and the range of the average effluent concentrations was 1.4-2.2 μg/L. After achieving 180 days of stable performance with BTEX addition, the total flow rate to the reactor was gradually increased by 20% increments to 160% of the original flow (36.4 L/day). Increases by 20% and 40% had no apparent effect on reactor performance, but increase by 60% required 30 days before effluent quality returned to previous values. Composition of the culture was monitored throughout operation of the reactor using denaturing gradient gel electrophoresis (DGGE). The culture consisted of Flavobacteria-Cytophaga and organisms with high similarity to the known MTBE degrader PM1.
Biodegradation of the energetic compound TNT through a multiple-stage treatment approach
Authors: Davel J. , Suidan M.T. , Adrian N.
Published: May 2018

Biodegradation of the energetic compound 2,4,6-trinitrotoluene (TNT) and its intermediate 2,4,6-triaminotoluene (TAT) was investigated in this study. From previous investigations, a relationship between the biological utilization of ethanol as co-substrate for the reduction of TNT under anaerobic conditions was proposed using an anaerobic fluidized-bed reactor (AFBR). In this study, the theoretical co-substrate requirement for reduction of TNT to TAT was further investigated through the systematic lowering of the ethanol loading to the reactor. Near complete reduction to TAT was observed up to a critical ethanol loading point, as well as the production of methane from the limited excess available ethanol. Once ethanol deficient loading conditions were established, the increased presence of incompletely reduced degradation intermediates, such as 2,4-diamino-6-nitrotoluene, and even TNT, was observed. The cessation of methanogenesis confirmed that no excess ethanol was available. Degradation of the TAT intermediate in the reactor effluent was investigated using two second-stage reactors under oxidizing conditions. The first was an aerobic activated sludge reactor, and the second was a denitrifying fluidized-bed reactor (DenFBR). The aerobic reactor was successful in lowering the chemical oxygen demand (COD), but complete removal of TAT was not accomplished. Because of TAT polymerization and auto-oxidation under aerobic conditions, it was difficult to confirm to what extent of TAT removal was biological. In the DenFBR, incompletely reduced TNT intermediates were not successfully degraded, but strong evidence existed for the degradation of TAT. This is the first known report of second stage degradation of TAT under denitrifying conditions.
Heterogeneous ultrasonic destruction of aqueous organic contaminants
Authors: Suri R.P.S. , Kamrajapuram A.
Published: May 2018

Sonolysis is emerging as an effective advanced technology for destruction of organic pollutants in wastewater. The focus of this study is to investigate the potential of enhancing the sonochemical destruction of aqueous organics. Increasing the contaminant destruction rate will reduce the reaction time, and possibly reduce the cost of treatment. For this purpose, the effect of H2O2 and/or silica in the presence of ultrasound is examined for destruction of 2-chlorophenol (2-CP). The effect of silica dosage (1, 5, 10, and 20 g/L), peroxide dosage (50, 75, and 100 mg/L), and pH (3,7,and 11) is examined. Low solution pH provided higher destruction of 2-CP. The presence of peroxide or silica enhanced the destruction of 2-CP. The optimum silica dosage was 5 g/L. 100 mg/L of peroxide and 5 g/L of silica present together enhanced 2-CP sonolytic destruction by a factor of approximately 2 as compared to 2-CP destruction with ultrasound only.
Inactivation of E. coli and helminth eggs in aerobic and anaerobic effluents using UV radiation
Authors: de Lemos Chernicharo C.A. , de Castro Silva J.C. , Zerbini A.M. , Godinho V.M.
Published: May 2018

This paper evaluates the performance of a simplified bench-scale UV-photoreactor used to inactivate Escherichia coli and eggs of Ascaris lumbricoides. The photoreactor consisted of a tubular unit constructed with PVC tube, 100 mm diameter and 45 cm total height, with a low-pressure mercury lamp adapted in the centre of the tube. The reactor was tested to disinfect the effluents from a trickling filter and from an UASB reactor, both fed with domestic sewage. The results showed an excellent performance of the photoreactor, with very high E. coli inactivation efficiencies being observed for the aerobic effluent (in the range of 4 to 5 log-units, for doses varying from 50.7 to 13.6 mW.s.cm−2) and also for the effluent from the UASB reactor (usually above 4 log-units, for doses of 20.3 and 13.6 mW.s.cm−2). In relation to the inactivation of helminth eggs, it was observed that UV radiation significantly affected the development of eggs of Ascaris lumbricoides, with the better results being obtained for radiation times of 40 and 60 seconds (doses of 13.6 and 20.3 mW.s.cm−2, respectively), when approximately 65% of the eggs remained in the stage of single cell and only 9 to 10% were able to fully develop to the stage of motile larva.
RIONET: a water quality management tool for river basins
Authors: Reuter H. , Krause G. , Mönig A. , Wulkow M. , Horn H.
Published: May 2018

The water quality management tool RIONET for river basins has been developed with regard to the EU Water Framework Directive. The management tool can simulate the water quality in catchment basins not only in the dimension of a single river but in whole river networks. A submodel of the IWA River Water Quality Model No. 1 is used in RIONET. The river model is based on the assumption that self purification processes in the river takes place both in the benthic biofilm and the bulk water phase. Laboratory experiments with sediment cores underline the major role of the benthic biofilm. The input parameters of the management tool such as volumetric flow rates from waste water treatment plants and flow velocities and discharge in the main river and its tributaries can be loaded directly from geographic information systems (GIS). The subcatchment basin of the river Bode in Saxon Anhalt was used for test runs of RIONET.
Development of seaweed biomass as a biosorbent for metal ions
Authors: Lau T.C. , Ang P.O. , Wong P.K.
Published: May 2018

Three seaweed species collected from Hong Kong waters were screened for their adsorption abilities for Cu2+, Ni2+ and Zn2+; and Ulva lactuca having the highest metal ion removal capacity (RC) was chosen for further study. Effects of algal biomass and medium pH on the metal ions RC of Ulva lactuca were determined and optimized. Under the optimal conditions of the corresponding metal ions, the algal Cu2+, Ni2+ and Zn2+ RCs were 65.54, 21.00 and 49.54 mg/g, respectively. The presence of other cations and anions affected the metal ions adsorption by the seaweed. The effect was dependent on the combination between the target metal ions and other cations/anions. The kinetic study revealed that the adsorption of Cu2+, Ni2+ and Zn2+ by Ulva lactuca fitted the Langmuir isotherm. Comparing with 0.1 M HCl, citric acid, thiourea, EDTA and HNO3, 0.1 M H2SO4 efficiently recovered close to 100% adsorbed metal ions from Ulva lactuca. In three successive adsorption-desorption cycles, reduction in metal ion RCs was found in the second and third cycles, but almost all adsorbed metal ion could be recovered.
Degradation of halogenated aliphatic compounds utilizing sequential anaerobic/aerobic treatments
Authors: McCue T. , Hoxworth S. , Randall A.A.
Published: May 2018

The objective of this research was to determine if either methanogenic or sulfidogenic reductive dechlorination could survive an alternating anaerobic/aerobic sequence to biologically transform halogenated aliphatic hydrocarbons (HACs), specifically tetrachloroethylene (PCE), trichloroethylene (TCE), cis-1,2 dichloroethylene (cDCE), trans-1,2 dichloroethylene (tDCE), 1,1 dichloroethylene (1,1DCE) and vinyl chloride (VC). This ability was considered to be a necessary prerequisite for complete anaerobic/aerobic mineralization of halogenated aliphatic hydrocarbons by a single microbial consortia. Chlorinated solvents, which are among the most common groundwater contaminants, have been partially dechlorinated using single-stage anaerobic environmental treatment strategies. Various types of bacteria typically reductively dechlorinate PCE and TCE to cDCE and VC in an anaerobic environment, including methanogens, sulfidogens, and homoacetogens. The problem lies in the fact that reductive dechlorination typically leads to an accumulation of daughter compounds (cDCE, VC) which are more toxic than their parent compounds (PCE, TCE). Furthermore, PCE and (to a lesser extent) TCE, are resistant to dechlorination in aerobic environments. In contrast, VC and cDCE are readily oxidized co-metabolically in an aerobic environment by methanotrophic bacteria, and others using oxygenases (e.g. toluene oxidizers). Results from this research showed that both methanogenic and sulfidogenic reductive dechlorination could resume after transient exposures to both oxygen and hydrogen peroxide (H2O2). In fact, for cycles as frequent as 10 days between aerobic treatment cycles, reductive dechlorination was observed to resume at rates at least as rapid as microcosms not exposed to aerobic treatments.
Risk assessment of a dam-break using GIS technology
Authors: Seker D.Z. , Kabdasli S. , Rudvan B.
Published: May 2018

Flood disasters cause massive loss of human lives and immense damage to the infrastructure and economic activities, not only in Turkey but also all over the world. Governments consider several long-term and short-term precautions for flood control. The numerical simulation of dam-break problems could be accomplished with geographic information systems and innovation maps. Spread of the flood wave after a dam break can be predicted using these enabling technologies. This kind of advanced modelling technology is becoming an inevitable tool for the decision-making process. Data produced by GIS are used as initial values for FLDWAV. ArcView GIS has been used to produce a Digital Elevation Model and visualization of dam-break effects and propagation of a possible flood wave. Using GIS techniques and hydrologic modelling software, possible effects and damage of a dam-break flood have been investigated and results were simulated to show significant dam break effects on the region.
Color removal ability of a streptomycin resistant decolorizing strain Rhodococcus erythropolis (ATCC 4277.1)
Authors: Hu T.-L.
Published: May 2018

Rhodococcus erythropolis (ATCC 4277.1) is a streptomycin resistant mutant of ATCC 4277, which can decolorize the sulfonated azo dye of Orange II and Amido Black. Pseudomonas luteola is a decolorizing strain, which was isolated from sludge resulting from the treatment of dyeing wastewater. This study had two purposes: 1) to determine the color removal capacity of R. erythropolis (ATCC 4277.1) for Red 22, V2RP and RP2B dyes; and 2) to compare the decolorization capability of R. erythropolis (ATCC 4277.1) to that of P. luteola, a wild type decolorizing strain.

R. erythropolis (ATCC 4277.1) grew well in broth containing the azo dyes of Red 22, V2RP or RP2B, and the color of azo dyes could be removed within five days of incubation. The total percentage of color removal was 70%, 30% and 23%, respectively. Color removal by R. erythropolis occurred through a process of degradation, since after five day's incubation in a dye containing broth, the color of R. erythropolis cells remained the same as their original pinkish white color. Comparison of the color removing ability between R. erythropolis and P. luteola showed that the specific color removal (SCR) of R. erythropolis was 1.52 mg of RP2B degraded per gram of dried cells, and that of SCR of P. luteola was 31.7 mg, which was 30 fold higher than that of R. erythropolis.
Measuring in-stream productivity: the potential of continuous chlorophyll and dissolved oxygen monitoring for assessing the ecological status of surface waters
Authors: Jarvie H.P. , Love A.J. , Williams R.J. , Neal C.
Published: May 2018

Continuous (hourly) measurements of dissolved oxygen and chlorophyll (determined by fluorimetry) were made for an inter-linked lowland river and canal system. The dissolved oxygen data were used to estimate daily rates of re-aeration, photosynthesis and respiration, using a process-based analytical technique (the Delta method). In-situ fluorimeter measurements of chlorophyll were ground-truthed on a fortnightly basis using laboratory methanol extraction of chlorophyll and spectrophotometric analysis. Water samples were also analysed for algal species on a fortnightly basis. The river and canal exhibited very similar rates of photosynthesis and respiration during the summer of 2001, despite much higher chlorophyll concentrations and total algal counts, indicating that benthic algae and/or aquatic macrophytes may be making an important contribution to photosynthesis rates in the river. Suspended algal populations in the canal are dominated by planktonic species, whereas the river has a higher proportion of species which are predominantly benthic in habitat. The river exhibited higher rates of respiration, reflecting a higher organic loading from external (e.g. sewage effluent) sources.
Prediction of climate change effects on fish communities in the Mackinaw River watershed, Illinois, USA
Authors: Herricks E.E. , Bergner E.R.
Published: May 2018

As part of an integrated assessment of multiple sector impacts produced by predicted changes in climate we have integrated a set of models, which provide predictions of fish populations under changing flow and temperature regimes. The core of the approach is the U. S. Fish and Wildlife Service Physical Habitat Simulation Model (PHABSIM). PHABSIM estimates habitat conditions based on flow, which are life stage specific. The output from PHABSIM is used to model fish populations, considering both flow and a temperature threshold, which affects spawning date. Water temperatures were modelled based on air temperature. The resulting assessment tool provides the means to evaluate the effect of multiple stressors produced by climate change scenarios. The model has been used to estimate smallmouth bass (Micropterus dolomieui) populations for representative reaches of the Mackinaw River, Illinois. The model has been used to illuminate population effects of changing flow and temperature under historical climate/weather conditions, as well as under climate change scenarios. The integrated models in the assessment tool have provided a useful addition to watershed management, improving our capacity to evaluate natural resources impact at temporal scales typical of climate change, and management response systems.
Nitrification of high strength ammonia wastewater and nitrite accumulation characteristics
Authors: Kim D.J. , Chang J.S. , Lee D.I. , Han D.W. , Yoo I.K. , Cha G.C.
Published: May 2018

Biological nitrogen removal via the nitrite pathway in wastewater treatment is very important in saving the cost of aeration and as an electron donor for denitrification. Wastewater nitrification and nitrite accumulation were carried out in a biofilm airlift reactor with autotrophic nitrifying biofilm. The biofilm reactor showed almost complete nitrification and most of the oxidized ammonium was present as nitrite at the ammonium load of 1.5 to 3.5 kg N/m3·d. Nitrite accumulation was stably achieved by the selective inhibition of nitrite oxidizers with free ammonia and dissolved oxygen limitation. Stable 100% conversion to nitrite could also be achieved even under the absence of free ammonia inhibition on nitrite oxidizers. Batch ammonium oxidation and nitrite oxidation with nitrite accumulating nitrifying biofilm showed that nitrite oxidation was completely inhibited when free ammonia is higher than 0.2 mg N/L. However, nitrite oxidation activity was recovered as soon as the free ammonia concentration was below the threshold level when dissolved oxygen concentration was not the limiting factor. Fluorescence in situ hybridization analysis of cryosectioned nitrite accumulating nitrifying biofilm showed that the β-subclass of Proteobacteria, where ammonia oxidizers belong, was distributed outside the biofilm whereas the α-subclass of Proteobacteria, where nitrite oxidizers belong, was found mainly in the inner part of the biofilm. It is likely that dissolved oxygen deficiency or limitation in the inner part of the nitrifying biofilm, where nitrite oxidizers exist, is responsible for the complete shut down of the nitrite oxidizers activity under the absence of free ammonia inhibition.
Enhanced nitrogen removal in SBRs bypassing nitrate generation accomplished by multiple aerobic/anoxic phase pairs
Authors: Katsogiannis A.N. , Kornaros M. , Lyberatos G.
Published: May 2018

A lab-scale SBR was used for the study of nitrogen removal from a synthetic wastewater with an ammonium-nitrogen concentration of 50 mg/L. The react phase of the reactor operation was divided into three sets of consecutive aerobic and anoxic periods with a duration ratio of 1:3 (20 min aerobic and 1 h anoxic phase). Under these operating conditions, nitrogen removal was achieved via nitrite i.e. no nitratification (oxidation of nitrite to nitrate) and hence no denitratification (reduction of nitrate to nitrite) was taking place in the aerobic and anoxic phase, respectively. This was attributed to the suppression of the nitrite-oxidizers activity due to the short aerobic phase duration. This presumption was supported by the ever decreasing amount of nitrate-nitrogen generated in the react phase during the transient, even when the activated sludge of the reactor was supplemented with additional nitrite-oxidizers. On the other hand, denitrification was mainly based on stored carbon sources, as long as the organic carbon (provided in the form of acetate) was never accumulated during the anoxic/anaerobic fill phase of the reactor operation.
Efficiency of the Activated Sludge Model no. 3 for German wastewater on six different WWTPs
Authors: Wichern M. , Lübken M. , Blömer R. , Rosenwinkel K.-H.
Published: May 2018

In 1999, the Activated Sludge Model No. 3 by the IWA Task Group on Mathematical Modelling for the Design and Operation of Biological Wastewater Treatment was presented. The model is used for the simulation of nitrogen removal. The simulations in this paper were done on the basis of a new calibration of the ASM 3 by Koch et al., with the easily degradable COD measured by respiration. For modelling of EBPR the BioP-Module of Rieger et al., was used.

Six German wastewater treatment plants were simulated during this research to test the existing set of parameters of the models on various large scale plants. It was shown that changes for nitrification and enhanced biological phosphorus removal in the set of biological parameters were necessary. Sensible parameters and recommended values are presented in this article. Apart from the values of the changed biological parameters, we will in our examination discuss the modelling of the different activated sludge systems and the influent fractioning of the COD. Two plants with simultaneous denitrification in the recirculation ditch (EBPR) are simulated, one with preliminary dentrification, one with intermittent denitrification (EBPR), one with cascade denitrification (EBPR), and one pilot plant according to the Johannesburg-process (EBPR) which was simulated over a period of three months.
Elevated precursor 16S rRNA levels suggest the presence of growth inhibitors in wastewater
Authors: Stroot P.G. , Oerther D.B.
Published: May 2018

Conventional activated sludge systems require bacteria to grow to avoid washout through decay and routine solids wasting. Recently we developed a procedure targeting precursor 16S ribosomal RNA to measure the in situ growth activity of phylogenetically defined microbial populations, and this procedure was used to study the growth of bacteria in activated sludge systems. The current study significantly expands this previous work by quantifying levels of precursor 16S ribosomal RNA within individual cells of pure cultures of bacteria exposed to various culture conditions. Initially, three ranges (Type I, Type II, and Type III) of precursor 16S ribosomal RNA levels were defined by whole cell fluorescence in situ hybridization of a pure culture of Acinetobacter calocaceticusT prepared in three culture conditions. Low levels of precursor 16S ribosomal RNA (Type I) corresponded to a stationary phase culture prepared overnight in Luria-Bertani medium. Intermediate levels of precursor 16S ribosomal RNA (Type II) corresponded to a culture transferred into fresh Luria-Bertani medium, and high levels of precursor 16S ribosomal RNA (Type III) corresponded to a culture treated with the growth inhibiting antibiotic chloramphenicol. Subsequently, the abundance of individual cells of each Type were measured in four different pure cultures after exposure to 0.45-mm filtered primary effluent collected from four different conventional activated sludge treatment plants in Cincinnati, OH, USA. Individual cells of each Type were observed in the culture of A. calcoaceticusT exposed to each of the four primary effluents. Only Type I cells were observed in cultures of A. johnsoniiT, A. johnsonii strain 210a, and Escherichia coliT exposed to each of the four primary effluents. These results suggest that the growth of A. calcoaceticusT was inhibited by an unidentified component of filtered primary effluent present in each of the four wastewaters; whereas the growth of A. johnsoniiT, A. johnsonii strain 210a, and E. coliT were not inhibited. These results have significance for understanding the growth of phylogenetically defined microbial populations within activated sludge treatment systems. If the pattern of elevated p16S rRNA levels observed in A. calcoaceticusT is prevalent in many microbial populations in activated sludge systems, this may have implications for preventing washout of critical microbial populations that may be experiencing growth inhibition.
Relationship between flocculation of activated sludge and composition of extracellular polymeric substances
Authors: Wilén B.-M. , Jin B. , Lant P.
Published: May 2018

Activated sludge flocs are a flocculated mass of microorganisms, extracellular polymeric substances (EPS) and adsorbed organic and inorganic material. The structure of the flocs is very heterogeneous and flocs with very different properties and morphologies may occur, depending on the conditions in the activated sludge treatment plant and wastewater composition. Present thinking suggests that cations, such as calcium, create cationic bridges with EPS excreted by the bacteria and thereby hold the various floc constituents together. However, due to the complex and heterogeneous nature of activated sludge, the mechanisms have neither been thoroughly investigated nor successfully quantified. A better understanding and description of the biological flocculation process is necessary in order to establish more efficient operational strategies. The main aim of this study was to get a comprehensive and unique insight into the floc properties of activated sludge and to assess the relative impact of chemical and physical parameters. A variety of sludges from full scale treatment plants with different settling properties were characterised. The interrelationships between floc parameters such as composition of EPS, surface properties and floc structure, and their effect on the flocculation and separation properties were assessed. The results indicate that the EPS, both in terms of quantity and quality, are very important for the floc properties of the activated sludge. However, presence of filaments may alter the physical properties of the flocs considerably. The EPS showed positive correlations to sludge volume index (SVI) if only sludges with low or moderate numbers of filaments were included. The surface properties were more affected by the composition of the EPS than by the number of filaments. The EPS showed positive correlation to negative surface charge and a negative correlation to relative hydrophobicity and flocculation ability. The negative correlation between flocculation ability and amount of EPS was surprising. The shear sensitivity, measured as degree of erosion of flocs when subjected to shear, was more affected by floc size and number of filaments than amount of EPS.
Elimination costs for different wastewater compounds
Authors: Schulz A. , Obenaus F. , Egerland B. , Reicherter E.
Published: May 2018

The present report presents the system and discusses the results of the cost calculation for the reduction/elimination of different wastewater and sludge compounds. These costs were calculated for different types of processes at 102 wastewater treatment plants of Emschergenossenschaft/Lippeverband and Aggerverband. Comparing enhanced biological phosphorus removal and precipitation, one of the results indicates that in general the costs for elimination of one kilogram of phosphorus are lower in the plants in which only chemical precipitation is used for P reduction. Further results of the cost calculation will be presented with a discussion of their possible influence on planning decisions.