bluuebunny/crossref_metadata_2025 huggingface dataset:
RDX degradation using an integrated Fe(0)-microbial treatment approach
Authors: Wildman M. J. , Alvarez P. J.
Published: May 2018

RDX is a persistent and highly mobile groundwater contaminant that represents a major remediation challenge at numerous munitions manufacturing and load-assemblage-package facilities. This work presents proof of concept that permeable reactive iron barriers might be a viable approach to intercept and degrade RDX plumes. Specifically, RDX was rapidly reduced in aquifier microcosms amended with Fe(0) powder, and in flow-through columns packed with steel wool. The rate and extent of RDX degradation in microcosms was enhanced by anaerobic bacteria that feed on cathodic hydrogen (i.e., H2 produced during anaerobic Fe(0) corrosion by water). Apparently, the hydrogenotrophic consortium that exploits Fe(0) corrosion as a metabolic niche participated in the further degradation of heterocyclic intermediates produced by the reaction of RDX with Fe(0). Reductive treatment of RDX with Fe(0) also reduced its toxicity to microorganisms and enhanced its subsequent biodegradability under either anaerobic or anaerobic conditions. Therefore, a combined or sequential Fe(0)-biological treatment approach might improve treatment efficiency.
Development of hexachlorobenzene-dechlorinating mixed cultures using polysorbate surfactants as a carbon source
Authors: Yeh D. H. , Pavlostathis S. G.
Published: May 2018

The use of three nonionic polysorbate surfactants – Tween 60, 61 or 65 – as the sole carbon source to sustain methanogenesis and dechlorination, as well as the effect of long-term exposure of enriched cultures to these surfactants, was investigated through the development of three sediment-derived cultures. Over a one-year period, the carbon source in these cultures was gradually switched from glucose and methanol to surfactant only, while the surfactant concentration was increased from an initial concentration of 100 mg/L to 400 mg/L. In each feeding cycle, the surfactants were partially degraded and converted to methane. Transition from glucose to Tween surfactants as the electron donor did not affect the rate, extent, and pathway of HCB transformation. These surfactants sustained the reductive dechlorination of HCB even after one year of continuous addition to the enriched cultures. This study demonstrated that reductive dechlorination of HCB sustained by the fermentation of Tween surfactants is feasible. The results support the use of anaerobically degradable Tween surfactants for the biotransformation of polychlorinated organic compounds. In principle, these surfactants could be used to simultaneously increase the bioavailability of subsurface contaminants while serving as the carbon and electron source for microbial reductive dechlorination.
On the contribution of background sources to the heavy metal content of municipal sewage sludge
Authors: Koch M. , Rotard W.
Published: May 2018

The role of human excretion, drinking water, and deposition as a source of heavy metals to municipal sewage was investigated and compared with common levels in sludge for soil application. These sources contributed more than half of the copper (Cu), zinc (Zn), and lead (Pb) content of municipal sewage sludge for soil application, while other sources dominated the fluxes of chromium (Cr) and cadmium (Cd). Drinking water was an important source for Cu and Zn. Deposition contributed about 40% to the Pb flux. Faecal excretion commonly caused less than 10% of the heavy metal load, while urinary excretion was here a negligible heavy metal source.
Estrogenic influences of estradiol-17b, p-nonylphenol and bis-phenol-A on Japanese Medaka (Oryzias latipes) at detected environmental concentrations
Authors: Tabata A. , Kashiwada S. , Ohnishi Y. , Ishikawa H. , Miyamoto N. , Itoh M. , Magara Y.
Published: May 2018

Mature male medaka were continuously exposed to 0.005, 0.0–5 or 1.0 ppb of estradiol-17β (E2 or 0.1, 10 or 100 ppb of p-nonylphenol (NP) or bis-phenol-A (BPA). Female-specific proteins (Fsp) were induced in medaka exposed to 0.005 ppb of E2, 0.1 ppb of NP, or 10 ppb of BPA. Concentrations of 0.005 pbb of E2 and 0.1 ppb of NP corresponded to concentrations of these chemicals detected in river water in Japan. The abilities of the 3 chemicals to induce Fsp were E2> NP> BPA. Embryonic medaka were exposed to E2, NP and BPA under conditions of static-renewal for 200–230 days until pre-maturity. Survival ratios of medaka exposed to E2 and NP declined in concentrations more than 25 ppb and 50 ppb, respectively. The groups of medaka exposed to E2 had individuals with testis-ova or abnormal gonad. There was no male in exposure to 1.0 ppb E2. When exposed to 100 ppb of NP or BPA, abnormal gonad was also detected. Abnormal anal fin (female-like) was observed in male exposed to 100 ppb of NP. The LC50 values for each of the 3 chemicals were much higher than the concentrations detected in water in the environment—the 3 chemicals were considered to have no lethal effect on medaka in aquatic environments. However, exposures to E2 or NP at environmental concentrations induced Fsp. BPA also had the ability to affect medaka as an environmental estrogen, although its extrogenic activity was weaker than that of E2 or NP.
Comparison between estrogenicities estimated from DNA recombinant yeast assay and from chemical analyses of endocrine disruptors during sewage treatment
Authors: Tanaka H. , Yakou Y. , Takahashi A. , Higashitani T. , Komori K.
Published: May 2018

This study discusses the estrogenicity and the extent of estrogenic effects, of sewage and treated sewage in public sewage treatment plants in Japan. The estrogenicity in this study was measured with a DNA recombinant yeast strain. Using this method, 43 chemicals that are suspected to have estrogen-like effects were measured and their estrogenicities were evaluated in terms of 17β-estradiol equivalents by comparison with the estrogenicity of 17β-estradiol. 17β-estradiol equivalents of influent and effluent sampled from 20 sewage treatment plants (STPs) were measured with this method. Because the concentrations of endocrine disruptors (EDs) in the STPs were monitored by the Ministry of Construction (MOC), the estrogenic effects estimated from the chemical data were obtained as a theoretical estrogenicity in terms of 17β-estradiol equivalent. The results suggest that STPs effectively reduce the estrogenicity and the theoretical estrogenicity during treatment, and that there were some differences between the estrogenicity assayed by the yeast and the theoretical estrogenicity in many STPs, particularly in influent sewage. Therefore, it is implied that unknown estrogen-like substances or antagonists might exist in influent sewage and treated sewage in STPs.
Catalytic wet air oxidation of p-nitrophenol (PNP) aqueous solution using multi-component heterogeneous catalysts
Authors: Yoon C.-H. , Cho S.-H. , Kim S.-H. , Ha S.-R.
Published: May 2018

This study investigated the decomposition of high strength p-nitrophenol (PNP) of 2,000 mg/l (3,400 mg of COD/1,250 mg of TOC) by catalytic wet air oxidation. Multi-component heterogeneous catalysts were used as catalysts for this purpose. The study results using a batch reactor showed that catalyst “D” (Mn-Ce-Zr 22.4 g plus CuSO4 1.0 g; Mn-Ce-Zr-Cu [CuSO4]) was more effective (56˜74%) than catalyst “A” (Mn-Ce-Zr 22.4 g) under the given conditions (O2 partial pressure of 1.0 MPa; temperature of 170˜190°C; 30 min of reaction time). The best result was obtained when 2 g of Mn-Ce-Zr-Cu [CuSO4] was used per 1L of PNP aqueous solution. COD and TOC removal efficiencies were 18% and 23% without catalysts during 20 min of reaction at 190°C. They were improved to 79% and 71% with 2 g/L of Mn-Ce-Zr-Cu [CuSO4] under the same conditions. The ratio of BOD5/COD was measured to evaluate biodegradability. It was 0.05 without catalyst and increased to 0.33 with 2 g/L of Mn-Ce-Zr-Cu [CuSO4] for 20 min of reaction.
Peroxidase-catalyzed removal of phenols from a petroleum refinery wastewater
Authors: Wagner M. , Nicell J. A.
Published: May 2018

The phenol content of a petroleum refinery wastewater was reduced below the discharge limit following treatment with horseradish peroxidase and H2O2. Approximately 58% of COD, 78% of BOD5, and 95% of toxicity were removed along with the phenols. As a result of treatment, phenols were transformed into less biodegradable compounds which could be removed by subsequent coagulation and precipitation. Optimization of the peroxide concentration led to 20% enzyme savings. The use of PEG and chitosan as protective additives resulted in 4 and 25-fold reductions in enzyme requirements, respectively. Phenol removal did not appear to be adversely affected by the presence of other hydrocarbons that are frequently present in refinery wastewaters.
Practical energy and water management through pinch analysis for the pulp and paper industry
Authors: Koufos D. , Retsina T.
Published: May 2018

In this paper we briefly describe pinch technology as a practical tool for effective energy management in the pulp and paper industry. Results indicate good steam savings. Recently pinch technology has been extended to water management. We have developed a customized methodology for the pulp and paper industry, to eliminate or reduce fresh water intake. Although the methodology is not fully developed it is a “proof of concept” that pinch principles can be applied to water related problems. The eventual combination of both thermal and water pinch will thus provide a structured and comprehensive approach for plant wide efficiency increase.
Removal and recovery of heavy metals from wastewaters by supported liquid membranes
Authors: Yang X. J. , Fane A. G. , MacNaughton S.
Published: May 2018

The removal and recovery of Cu, Cr and Zn from plating rinse wastewater using supported liquid membranes (SLM) are investigated. SLMs with specific organic extractants as the liquid membrane carriers in series are able to remove and concentrate heavy metals with very high purity, which is very promising for recycling of heavy metals in the electroplating industry. A technical comparison between the membrane process and the conventional chemical precipitation process was made.
Acrylonitrile removal from synthetic wastewater and actual industrial wastewater with high strength nitrogen using a pure bacteria culture
Authors: Wang C.-C. , Lee C.-M. , Cheng P.-W.
Published: May 2018

A gram-negative rod-shaped bacteria (strain AAS6), capable of utilizing acrylonitrile as the sole source of both carbon and nitrogen, was utilized to investigate the removal of acrylonitrile in ABS resin manufacturing wastewater. Both synthetic wastewater, containing a high concentration of acrylonitrile, and actual wastewater obtained from an ABS manufacturing factory were used. The result indicated that strain AAS6 was capable of completely removing acrylonitrile from synthetic wastewater containing less than 889 mg/l acrylonitrile and from actual industrial wastewater containing less than 400 mg/l acrylonitrile. Whether in synthetic wastewater or actual industrial wastewater, strain AAS6 showed approximately the same ability for acrylonitrile removal and used acrylic acid, a metabolic by-product of acrylonitrile, as the carbon source and ammonium as the nitrogen source. The bacteria could not directly metabolize other chemicals found in the actual industrial wastewater. However, its metabolic activities were not inhibited by the presence of compounds such as butadiene, styrene or acrylonitrile-styrene polymer. Thus, this strain is expected to play an important role in aeration tanks for treating ABS resin manufacturing wastewater.
Use of computer simulation for cycle length adjustment in sequencing batch reactor
Authors: Mikosz J. , Plaza E. , Kurbiel J.
Published: May 2018

The city of Nowy Targ located in Poland's highland operates the WWTP with classic SBR technology. In winter some decrease in process efficiency was observed. The research described in the paper was aimed at using computer simulation to adjust SBR cycle length and structure in order to minimize the effects of low wastewater temperature on biological CNP removal. The simulations performed at 6°C wastewater temperature showed that switching from 6 to 8 hours cycle and extension of the aeration phase length from 2.75 to 5 hours will increase the effectiveness of biological nitrification and biological phosphorus removal. The change in practice will not affect COD value in the effluent. Based on the simulation results a new SBR operational strategy was proposed for Nowy Targ WWTP.
Implementation, study and calibration of a modified ASM2d for the simulation of SBR processes
Authors: Marsili Libelli s. , Ratini P. , Spagni A. , Bortone G.
Published: May 2018

An enhanced process model for SBRs has been developed. Though the basic mechanism largely draws on the Activated Sludge Model n. 2d, its new features are the splitting of the nitrification stage in a two-step process, according to the well known Nitrosomonas - Nitrobacter oxidation sequence, and an improved XPAO dynamics, involved in the anaerobic/aerobic phosphorus removal process.

The model was implemented through the DLL technique allowing complied C++ modules to be linked to an ordinary Simulink block diagram. The static sensitivity study revealed that if the parameter vector is partitioned into subsets of biologically related parameters and calibrated separately, the calibration procedure does not present particularly difficult aspects. Trajectory sensitivity showed also to which extent data collection could be optimised in order to improve calibration accuracy.

The study of the shape of the error functional generated by parameters couples allows a much more effective calibration strategy.
On-line control of a SBR system for nitrogen removal from industrial wastewater
Authors: Andreottola G. , Foladori P. , Ragazzi M.
Published: May 2018

In this study, laboratory-scale experiments were conducted applying the SBR activated sludge process to a wastewater from a wood factory operating on plywood production. Due to the fact that the wastewater is characterised with a high concentration of ammonia, the aim was to evaluate the nitrogen removal process with SBR system operating with a on-line control of ORP, pH and DO. The complete ammonia removal corresponded exactly to the “Ammonia Valley” in the pH versus time graphic. The ammonia removal efficiency in SBR was 99% at 20°C. The denitrification reaction was completed when in the ORP versus time graphic appeared the “Nitrate Knee”. From the experimental results the optimisation of the SBR cycle allowed the doubling of the applied load with respect to a not optimised cycle (performed in the same volume reactor), without a decrease in the removal efficiency. Moreover, the possibility of stopping the aeration just after the appearance of the Ammonia Valley allows an energy saving. The easy operation and the low cost make the SBR system an interesting option for the biological pre-treatment of plywood industry to be discharged into surface water.
The feasible sequential control strategy of treating high strength organic nitrogen wastewater with sequencing batch biofilm reactor
Authors: Cho B.-C. , Chang C.-N. , Liaw S.-L. , Huang P.-T.
Published: May 2018

The bio-kinetics and feasible sequential control strategy of treating high strength organic carbon and nitrogen wastewater were investigated by conducting the ABS manufacturing wastewater in a series of Sequencing Batch Biofilm Reactors (SBBRs). The on-line ORP, pH, and DO monitoring parameters were applied to identify the feature-points when ammonification, nitrification, and denitrification ends. The carbonaceous matter removal kinetics in the anaerobic and aerobic reaction stages can be expressed by the Michaelis-Menten equation. High efficiency of organic carbon removal and organic nitrogen ammonification in the anaerobic stage can eliminate the substrate competition and activation inhibition to nitrifying organisms in the following aerobic stage. In the sequencing nitrogen removal processes, the producing time and system ORP values of these feature-points have good function relationships with the influent COD loading rates of SBBR, which can be integrated into a set-point (set-time and set-ORP) sequential control strategy of nitrogen removal. The automatic control operation results revealed ORP was one of the major control parameters of the sequencing nitrogen removal process in SBBR system and high overall removal efficiency were obtained.
SBR as a relevant technology to combine anaerobic digestion and denitrification in a single reactor
Authors: Bernet N. , Delgenès N. , Delgenès J.-P. , Moletta R.
Published: May 2018

Two laboratory-scale sequencing batch reactors were used to study biological treatment of carbon and nitrogen in a new combined anaerobic-aerobic system. Piggery wastewater was used as a model effluent. The anaerobic reactor, fed with raw wastewater and nitrite/nitrate recycling from the aerobic reactor, carried out denitrification and anaerobic digestion of organic carbon. In the aerobic reactor, organic carbon removal and nitrification of ammonia to mainly nitrite occurred. Three recycle-to-influent ratios from1 to 3 were tested. The higher the recycle-to-influent ratio, the lower the concentrations of nitrogen oxides in the final effluent. Carbon removal efficiency was quite stable, whatever the ratio. However, the effect of this ratio was attenuated because of denitrification in the aerobic reactor, which increased the performances of the process. The use of sequencing batch reactors was essential to apply the configuration proposed, in order to combine denitrification and methanogenesis that require antagonistic conditions.
Exceptionally high-rate nitrification in sequencing batch reactors treating high ammonia landfill leachate
Authors: Doyle J. , Watts S. , Solley D. , Keller J.
Published: May 2018

The nitrogen removal capacity of a suspended culture system treating mature land fill leachate was investigated. Leachate containing high ammonium levels of 300-900 mg N/L was nitrified in a bench scale sequencing batch reactor. Leachate from four different landfills was treated over a two year period for the removal of nitrogen. In this time, a highly specific nitrifying culture was attained that delivered exceptionally high rates of ammonia removal. No sludge was wasted from the system to increase the throughput and up to 13 g/L of MLSS was obtained. Settleability of the purely nitrifying biomass was excellent with SVI less than 40 mL/g, even at the high sludge concentrations. Nitrification rates up to 246 mg N/(L h) (5.91 g N/(L d)) and specific nitrification rates of 36 mg N/(gVSS h) (880 mg N/(gVSS d)) were obtained. The loading to the system at this time allowed complete nitrification of the leachate with a hydraulic retention time of only 5 hours. Following these successful treatability studies, a full-scale plant was designed and built at one of the landfills investigated.
SBR technology in Germany - an overview
Authors: Teichgräber B. , Screff D. , Ekkerlein C. , Wilderer P. A.
Published: May 2018

The SBR technology is applied in about 1.3 % of the wastewater treatment plants (WWTP) in Germany. This caused the German Association for the Water Environment (ATV) to prepare the guideline ATV-M 210 to represent the state of the art for this type of WWTPs in Germany. The basic design parameters were derived from the standard ATV-A 131 for activated sludge plants to prepare a basis for the comparison of alternatives. In Bavaria numerous small WWTPs utilize SBR technology. Operational experiences show that these plants require specifically trained personnel. The plants produce effluents comparable to those of continuous flow plants in every respect. Hence the choice of system can be based on economic criteria.
From the lab to full-scale SBR operation: treating high strength and variable industrial wastewaters
Authors: Flapper T. G. , Ashbolt N. J. , Lee A. T. , O'Neill M.
Published: May 2018

This paper describes the path taken from client objectives through laboratory studies and detailed design to full-scale SBR operation and current research. Conventional municipal design principles have often been used to develop treatment processes for industrial wastewaters. The use of scientific trials to test design criteria offers the client a “tailor made” design fit for their particular wastewater character. In this project, a waste management company wished to upgrade their physical-chemical treatment plant to incorporate a biological reactor for treating a range of industrial wastewaters. Laboratory-scale trials were undertaken to determine appropriate design criteria for a full-scale biological process. These laboratory studies indicated that conventional design criteria were not appropriate and that a SBR configuration was optimal compared with an IDAR configuration. It was also found that a novel fungal:bacterial mixed liquor consortium developed, resulting in good effluent quality and settling properties. The treatment plant was able to be constructed and operational within a tight timeframe and budget, allowing the client to take advantage of a commercial opportunity. The plant has been operating since 1997 and meets its discharge conditions. By combining scientific studies with engineering principles, the end-user obtained a complete treatment plant to meet their specific needs. A further benefit of the laboratory trials is current research into the development of a fungal:bacterial SBR to treat industrial wastewaters. This offers ongoing knowledge to the operational full-scale SBR.
Opening speech of the 10th Stockholm Water Symposium
Authors: Skogsfors Sven-Erik
Published: May 2018

Competition for water resources must be turned to an involvement of all stakeholders in integrated water management development and in a global water conscience. We hope that our symposia and the World Water Week could continue, develop and be a yearly meeting-point where these visions are brought forward together with concrete actions.
Opening address of the 10th Stockholm Water Symposium
Authors: Larsson Kjell
Published: May 2018

One third of the world's population lives in countries with some level of water stress, a number that could increase to two thirds by the year 2025. Twenty percent of the world's population in 30 countries face water shortage, a figure that could rise to 30% of the world's population in 50 countries by 2025. One thousand freshwater fish species - and 1000 bird species - have been pushed to the edge of extinction by contamination of water.
Blanket development in a malting wastewater anerobic treatment
Authors: Martínez J. , López I. , Giani L. , Borzacconi L.
Published: May 2018

A 3 m3 pilot UASB reactor was operated with malting wastewater. In order to find the aggregation characteristics, the sludge concentration profile was determined throughout time. Reactor behaviour concerning the physical properties of the sludge can be evaluated using this procedure. Moreover, organic load per VSS can be calculated from this profile. The organic load based per VSS is more accurate as a design parameter than the volumetric load. Under the study conditions imposed the COD removal efficiencies achieved were about 85%. Organic loads of 0.6-0.7 kg COD/(kgVSS.d) were reached. After operating at 30°C, temperatures of 28°C and 15°C were tested, showing no decrease in COD removal efficiency. At week 15 the presence of granules was verified, and after that, sludge concentrations of 30-35 kg VSS/m3 were measured at the bottom of the reactor. The SVI of the granular sludge decreased to values below 20 mL/gVSS. The settlement velocity was 10 m/h, which is much greater than the recommended values for the settlement zone; therefore, no problems are to be expected in the settler regarding the sludge sedimentation. The biomass yield coefficient obtained was 0.10 gVSS/gCOD in agreement with literature values for brewering effluent.
Water scarcity and food security: alternative futures for the 21st century
Authors: Rosengrant M. W. , Cai X.
Published: May 2018

Water availability for agriculture - the major water user worldwide - is one of the most critical factors for food security in many regions of the world. The role of water withdrawals in irrigated agriculture and food security has been receiving substantial attention in recent years. This paper addresses key questions regarding water availability and food security, including: How will water availability and water demand evolve over the next three decades, taking into account availability and variability in water resources, the water supply infrastructure, and irrigation and nonagricultural water demands? What are the relationships among water scarcity, food production, and food security? How much of future food production will come from rainfed and irrigated areas? A global modeling framework, IMPACT-Water, is applied to explore answers to these questions using analysis.
Domestic sewage treatment in full-scale UASBB plant at Mangueira, Recife, Pernambuco
Authors: Florencio L. , Kato M. Takayuki , Cardoso de Morais J.
Published: May 2018

The anaerobic technology application for domestic sewage treatment in Pernambuco State (Brazil) is relatively recent. Some UASB reactors of less than 250 m3 were built in the Recife Metropolitan Region (RMR) in the 1990s. Mangueira (18,000 inhabitants) was the first neighborhood where the municipality built a plant with a bigger UASB reactor of 810 m3. It was intended to evaluate the performance and verify if such technology would be feasible. The objective would be the possible application of UASB reactors to the RMR, according to the new sewage master-plan under elaboration that would benefit about 3 million inhabitants.

The monitoring of the Mangueira UASB reactor over 30 months showed that satisfactory results were obtained. Three distinct operational phases occurred, in which efficiency varied from 60% up to 90% based on COD removal. The results were very dependent on the operation and maintenance, either in the plant or in the sewage collection. Significant amount of inert solids was measured inside the reactor. Despite the operational problems, the UASB was shown to be very robust and stable. Under high fluctuation of influent concentrations (150-750 mg COD/L) during the period, resulting in applied organic loading rate of 0.5 to 2.5 kg COD/m3.d, the average values of COD removal efficiency did not change significantly. An active biomass with specific methanogenic activity varying from 0.18 to 0.25 gCOD/gVSS.d was measured at the end of the period.
Commodification of water - the wrong prescription
Authors: Barlow Maude
Published: May 2018

The world faces a crisis of water stress and scarcity. This paper argues that current policies of economic globalization and privatisation are exacerbating environmental problems and that the real solutions will have a fundamentally different ethical basis
Denitrification on the top of UASB reactors of rice wastewaters
Authors: Lopes L. F. , Koetz P. R. , Santos M. S.
Published: May 2018

Parboiled rice industry is one of main food industries in the south of Brazil. The main parts of the processing are the humidification and gelatinization of the grain. This procedure increases the productivity and nutritive and cooking values of the product. Some of these industries in the region utilize upflow anaerobic sludge blanket (UASB) reactors as a biological treatment for carbon removal. For nitrogen removal, the proposed system aims to eliminate an extra denitrification reactor, making this step in the top of the UASB, an anoxic zone of the reactor. Nitrification was performed in aerated mixed reactor of 3,6 L. A fraction of the NR was recycled in the top of UASB reactor above the sludge blanket. Recycled ratio varied from 0; 1:0.5; 1:1.0; to 1:1.5. The maximum removal efficiency of NTK was 80%. The results confirm the viability of the proposed system for denitrification.
Anaerobic digestion of a nonionic surfactant: inhibition effect and biodegradation
Authors: Jiménez-González A. , Salazar-González M. , Gutiérrez-Rojas M. , Monroy O.
Published: May 2018

Nonionic surfactants are used worldwide in various industrial and household applications. Since these compounds are used in aqueous solutions, they primarily enter the environment through sewage and industrial wastewater treatment plants. The objective of this work was to evaluate the inhibitory effect of Triton X-100, a commercial nonionic surfactant, on the anaerobic digestion of lactose. Thus non-ionic surfactants acts as a non-competitive inhibitor with KI = 250 mgL−1 and a inhibition order of 2.4.

Nonetheless if give enough time the sludge was able to degrade 79% of Triton at 0.1 gL−1 d−1 in a UASB reactor. An activity test of this sludge showed that Triton inhibited the acetogenic (both propionic and butyric) and acetoclastic activities, while there were high fermentative and hydrogenotrophic activities (80% and 95%, respectively).
Towards a recycling society: ecological sanitation - closing the loop to food security
Authors: Esray Steven A.
Published: May 2018

Heterogenous catalytic ozonation of 2-chlorophenol (2-CP) in the presence of γ-alumina as a solid catalyst has been investigated in this research. It showed that the rate for degradation of TOC could increase from 21% to 43%. The pseudo-first reaction constants of 2-CP could increase from 0.8688 min-1 to 0.1270, increasing by approximately 40%. At the same time, the consumption of ozone was only half that of ozone alone. This research also explored the effects of the catalyst dosage, pH values and removal kinetics of 2-CP. In addition, three consecutive running with the same catalyst revealed insignificant reduction of the activity. Furthermore, the elimination of toxicity was evaluated by Microtox® analysis. The detoxification was more stable and with good results.
Flotation technique with coagulant and polymer application applied to the post-treatment of effluents from anaerobic reactor treating sewage
Authors: Reali A. P.M. , Penetra R. G. , de Carvalho M. E.
Published: May 2018

This paper presents the results of a study performed with a lab-scale batch DAF unit fed with previously coagulated (with FeCl3 and/or cationic polymer) effluent from a pilot-scale expanded bed anaerobic reactor treating domestic sewage. The association between ferric chloride and polymers was studied, aimed at sludge reduction. Ferric chloride dosages ranging from 15 to 65 mg.l−1 and polymer dosages from 0.25 to 7.0 mg.l−1 were investigated. Flocculation conditions were kept constant: 20 min of time (Tf) and 80 s−1 of mean velocity gradient (Gf). Air requirement was kept to 19.0 g of air.m−3 wastewater, using 20% recycle ratio and saturation pressure at 450 kPa. When the anaerobic reactor was operating at steady state conditions, it was possible to reduce the FeCl3 dosage from 65 to 30 mg.l−1 after applying 0.4 mg.l−1 of non-ionic polymer, before the DAF process. For these dosages, 79% COD removal (residual of 23 mg.l−1), 86% total phosphate removal (residual of 0.9 mg.l−1) and 98% turbidity removal (residual of 2.6 NTU) were observed. Furthermore, the use of adequate polymer together with 30 mgFeCl3.l−1 leads to the production of high rising rate flocs.
Feasibility of a pilot-scale UASB/trickling filter system for domestic sewage treatment
Authors: Chernicharo C.A.L. , Nascimento M.C.P.
Published: May 2018

This paper presents the results of pilot system comprised of one UASB reactor followed by one trickling filter (TF). The UASB reactor had a volume of 416 litres, being operated at an average hydraulic retention time (HRT) of 4 hours. The trickling filter had a useful volume of 60 litres, being operated at hydraulic and organic loading rates varying from 3.4 to 30.6 m3/m2.d and 0.3 to 3.9 kgBOD/m3.d, respectively. These different operational conditions characterised eight research phases. Both reactors were fed with domestic sewage pumped directly from the main interceptor of Belo Horizonte City, Brazil.

After almost 16 months of continuous monitoring, the UASB/TF system produced very good results in terms of COD and BOD removal, and also very low solids concentration in the final effluent. The average results of COD and BOD removal varied from 74 to 88% and from 80 to 94%, respectively, sufficient to maintain the COD concentration in the final effluent in the range of 60 to 120 mg/L and the BOD values systematically below 60 mg/L. The overall averages of SS in the final effluent were kept below 30 mg/L.

The UASB/TF system is a very promising alternative for the treatment of domestic sewage in Brazil and other developing countries, since the system can be designed with very short hydraulic retention times, resulting in a very compact and low cost treatment unit. Besides, the energy consumption and the labour costs are minimal.
Domestic sewage treatment in a pilot system composed of UASB and SBR reactors
Authors: Torres P. , Foresti E.
Published: May 2018

The results obtained from the operation of a treatment system composed of an anaerobic (up-flow sludge blanket - UASB) reactor followed by an aerobic (sequencing batch - SBR) reactor treating domestic sewage are presented and discussed. The pilot plant was monitored during 6 months, aiming to obtain performance data on organic matter, nitrogen and phosphate removal under different operating conditions.

The UASB reactor was operated at a constant hydraulic detention time (θ) of 6 h while the SBR performance was monitored in four different duration cycles (24, 12, 6 and 4 h) corresponding to aeration times (AT) of 22, 10, 4 and 2 h, respectively.

COD and TSS overall removal efficiencies (Eo) up to 91% and 84%, respectively, were achieved independently on the aeration time applied to the SBR. In respect to nitrification and phosphate removal, AT was found to be a determinating operating parameter. TKN removal of approximately 90% was achieved for AT equal to or higher than 10 h; complete nitrification occurred for AT higher than 4 h; significant phosphate removal (72%) occurred only at the AT of 2 h. It was not possible to achieve simultaneous efficient removal of nitrogen and phosphate, under the operating conditions imposed on the treatment system.
Ozone treatment of textile wastewaters for reuse
Authors: Ciardelli G. , Capannelli G. , Bottino A.
Published: May 2018

Treatment of textile wastewaters by means of an ozonation pilot plant are described. Wastewaters used were produced by a dyeing and finishing factory and were first treated in an active sludge plant and filtrated through sand. In the appropriate conditions very high colour removal (95-99%) was achieved and the effluent could be reused in production processes requiring water of high quality as dyeing yarns or light colorations. Even if the chemical oxygen demand of treated waters was still in a range (75-120 mg/l, a decrease of up to 60%) that was usually considered to be too high for recycling purposes, recycling experiments were successful. The economical viability of the techniques implementation was also demonstrated and the industrial plant is currently under realisation under an EU financed project.

The paper considers also the possible improvement of ozone diffusion by means of membrane contactors realised in a second pilot plant, in order to further reduce operating costs of the technique. With respect to traditional systems, the gas/liquid contact surface is much higher being that of the membrane. Ozone at the interface is therefore immediately solubilized and potentially consumed with no additional resistance to the mass transfer.
The role of chemical oxidation in combined chemical-physical and biological processes: experiences of industrial wastewater treatment
Authors: Bertanza G. , Collivignarelli C. , Pedrazzani R.
Published: May 2018

In this work, some experiences are described concerning the application of chemical oxidation in the treatment of industrial wastewaters in combination with other chemical-physical and/or biological processes. In the first case, two different wastewaters from saturated and unsaturated polyester resin production were considered. In a second case, optimal process conditions were assessed for the treatment of a wastewater deriving from polystyrene production. A third experience dealt with a comparison among different processes (flocculation, Fenton process, ozonisation, oxidation by means of ozone and hydrogen peroxide, oxidation by means of hydrogen peroxide and UV radiation), for the pretreatment of two industrial wastewaters (the first one being produced in a textile factory, the second one coming from detergent manufacturing). The evaluation of different processes was carried out by means of laboratory scale tests, considering treatment efficiency (organic substance removal, changes in wastewater biodegradability) and parameters (chemicals and energy consumption, sludge production) which play an important role in cost determination.
Dynamic phosphorus mass balance modeling of large watersheds: long-term implications of management strategies
Authors: Cassell E. A. , Kort R. L. , Meals D. W. , Aschmann S. G. , Dorioz J. M. , Anderson D. P.
Published: May 2018

The principles of mass balance, compartment-flux diagramming, and dynamic simulation modeling are integrated to create computer models that estimate phosphorus (P) export from large-scale watersheds over long-term futures. These Watershed Ecosystem Nutrient Dynamics (WEND) models are applied to a 275,000 ha dairy-documented watershed and a 77,000 ha poultry-dominated watershed in northeastern USA. Model predictions of present-day P export loads are consistent with monitoring data and estimates made using P export coefficients. For both watersheds P import exceeds P export and P is accumulating in the agricultural soils. Agricultural and urban activities are major contributors to P export from both watersheds. Continued urban growth will increase P export over time unless wastewater management is substantially enhanced and/or rates of urban growth are controlled. Agriculture cannot rely solely on the implementation of increasingly stringent conservation practices to reduce long-term P export but mustconsider options that promote P input/output balance. The WEND modeling process is a powerful tool to integrate the diversity of activities in watersheds into a holistic framework. Model outputs are suited to assist managers to explore long-term effects of overall watershed management strategies on P export in comparison to environmental and economic goals.
Novel heterogeneous catalysts in the wet peroxide oxidation of phenol
Authors: Ovejero G. , Sotelo J.L. , Martínez F. , Gordo L.
Published: May 2018

Catalytic wet peroxide oxidation (CWPO) of diluted aqueous solutions of phenol has been studied over a series of heterogeneous catalysts at 100°C under 1MPa air pressure. Several catalysts were prepared and tested including zeolitic materials exchanged with metallic ions such as Fe and Cu and different mixed oxides. Likewise, a Fe-TS- zeolite was synthesised by isomorphous substitution of Si atoms by Fe and Ti into the MFI zeolitic framework through hydrothermal synthesis of wetness-impregnated Fe2O3-TiO2-SiO2 xerogels. This material showed a complete phenol removal and TOC reduction of up to 68% under the reaction conditions, with a low leaching of iron species as compared to Fe-exchanged zeolitic materials. Perovskite of type LaTi0.45Cu0.55O3 was also tested, showing copper leaching of 22%, with a TOC conversion of 93% and total phenol removal. The capacity of Fe and Cu containing catalysts to promote free radicals in the presence of H2O2 as well as the thermal decomposition of the oxidant under the reaction conditions have also been studied. In the absence of hydrogen peroxide, Fe and Cu catalysts were not effective in order to decrease TOC content.
Control of non-point source pollution by a natural wetland
Authors: Kao C. M. , Wu M. J.
Published: May 2018

Wetland creation and restoration is a reliable and efficient technology for the remediation of contaminated water. Knowledge from the natural wetland systems would be necessary to enhance the operational efficiency of constructed wetlands. In this study, a mountainous wetland located in McDowell County, North Carolina, USA was selected to demonstrate the effects of the natural filtration and restoration system on the maintenance of surface water quality. The hydraulic retention time (HRT) for the wetland was 10.5 days based on the results from a dye release study. Water quality monitoring of the wetland was conducted from May to August 1997. One major storm event and baseline water quality samples were collected and analyzed. Analytical results indicate that this wetland removed a significant amount of non-point source (NPS) pollutants [more than 80% N removal, 91% of total suspended solid removal, 59% of total phosphorus removal, and 66% of chemical oxygen demand (COD) removal] caused by the studied storm event. Sediment accretion monitoring results indicate that the accretion rate in the wetland was only 4 mm/year. Therefore, the wetland would require 100 years to fill at the measured sediment accretion rate. The high organic content of sediments (16%) indicates that the wetland is building the characteristic organic layer on the bottom of the wetland. Results from this study would be very useful in the maintenance of natural wetlands and design of constructed wetlands for water treatment.
Impacts of agrochemical fertilizer on the aquatic environment of paddy fields in Vietnam
Authors: Ha S.-R. , Dung P. A. , Lee B.-H.
Published: May 2018

To evaluate the impacts of agrochemical fertilizer application on the aquatic environment of paddy fields in tropical regions, 7.04 ha of paddy field situated in northern Vietnam were selected as a study area. The fate of nutrient constituents was surveyed through a questionnaire as well as analytical observation. Taking the major environmental components of the paddy field into account, a mass-balance flow regarding fertilizing constituents such as nitrogen and phosphate was built up and used to estimate the contribution of fertilizer to paddy field water pollution. In the mass-flow analysis, the randomness of fertilizer used by local farmers is incorporated within the conventional input-output model. For the control volume of soil in 0–40 cm below paddy plot surface, the estimated average concentrations in soil were 1.8 ppm for inorganic nitrogen and 1.3 ppm for inorganic phosphate on the assumption of 50% non-excessive probability. From the reasonable consistency of the deduced concentrations of nutrients with observed ones, not only the mass balance of fertilizing substances but also the impacts of fertilizer on the paddy field aquatic environment in Vietnam could be understood. On the results from nutrient mass-balance analysis, it was found that 11.3–13.3 kg N/ha would percolate into the underground aquifer that is linked to surface channel flow in the vicinity of the paddy plots and affect the irrigation water quality. The nutrient portion in the materials harvested as grain and straw occupied 58% of total dosed nitrogen and 75.6% of total supplied phosphorus.
Interactions of hypochlorite ion and humic acid: photolytic and photocatalytic pathways
Authors: Gonenç D. , Bekbolet M.
Published: May 2018

Photolytic and photocatalytic interactions of hypochlorite ion and humic acid are investigated under various conditions. Humic acid oxidation by aqueous chlorine under dark conditions are expressed in terms of first order reaction kinetics. Upon irradiation (300 nm < λ < 400 nm), photolysis of aqueous chlorine affect the removal efficiency of humic acid via oxidation. TiO2 sensitised photocatalytic oxidation conditions reveal an increase in the TOC removal rate of humic acid in the presence of aqueous chlorine. Under the specified conditions, increasing the photocatalyst loading up to 1.0 mg/mL markedly increase the TOC removal rate.
Photocatalytic degradation of leather dye over ZnO catalyst supported on alumina and glass surfaces
Authors: Sakthivel S. , Neppolian B. , Palanichamy M. , Arabindoo B. , Murugesan V.
Published: May 2018

The photocatalytic degradation of leather dye, Acid green 16, has been investigated over a ZnO catalyst supported on two different materials, namely alumina and glass beads (3-5 mm diameter). Sunlight was used as the energy source. The alumina-supported ZnO outperformed the glass-supported ZnO under identical operational conditions suggesting that the dye molecules are adsorbed on the alumina supports to make a high concentration environment around the loaded ZnO. The degradation efficiency was greater at pH = 4 compared to other acidic and neutral pH. Also, the degradation efficiency was a little bit higher in alkaline medium, which correlates with the adsorption behaviour of acid green 16 on the alumina supported ZnO. The influence of inorganic oxidants like H2O2, FeCl3 and Fenton reagent on the degradation efficiency were systematically studied. The decolourisation and extent of degradation of the dye were determined by UV-VIS spectroscopy and COD reflux methods, respectively. Complete mineralisation of the dye was conformed by High performance liquid chromatography (HPLC) analysis.
Concentrating versus non-concentrating reactors for solar photocatalytic degradation of p-nitrotoluene-o-sulfonic acid
Authors: Parra S. , Malato S. , Blanco J. , Péringer P. , Pulgarin C.
Published: May 2018

The photocatalytic oxidation of the non-biodegradable p-nitrotoluene-o-sulfonic acid (p-NTS) in homogeneous (photo-Fenton reactions) and heterogeneous (with TiO2) solutions has been studied at a pilot-scale under solar irradiation at the Plataforma Solar de Almeria (PSA). In this study two different reactors were tested: a medium concentrating radiation system (Heliomans, HM) and a non-concentrating radiation system (CPC). Their advantages and disadvantages for p-NTS degradation have been compared and discussed. The degradation rates obtained in the CPC collector are around three times more efficient than in the HM collectors. However, in both systems, 100% of the initial concentration of p-NTS was removed. Kinetic experiments were performed in both systems using TiO2 suspensions. During the photodegradation, the disappearance of p-NTS was followed by HPLC, the mineralization of the solution by the TOC technique, the evolution of NO3-, NO2-, and SO4= concentration by ionic chromatography, the toxicity by the standard Microtox® test, and the biodegradability by BOD5 and COD measurements. The obtained results demonstrated the utility of the heterogeneous catalysis (using TiO2 as catalyst) as a pretreatment method that can be followed by a biological process.