bluuebunny/crossref_metadata_2025 huggingface dataset:
Runoff quality and pollution loadings from a tropical urban catchment
Authors: Yusop Z. , Tan L.W. , Ujang Z. , Mohamed M. , Nasir K.A.
Published: May 2018

Runoff quality draining from 17.14km2 urban catchment in Johor Bahru, Malaysia, was analysed. The land-use consists of residential (30.3%), agricultural (27.3%), open space (27.9%), industrial (8.1%) and commercial (6.4%) areas. Three storm events were sampled in detail. These storms produced stormflow between 0.84mm and 27.82mm, and peakflow from 2.19m3/s to 42.36m3/s. Water quality showed marked variation during storms especially for TSS, BOD and COD with maximum concentrations of 778mg/l, 135mg/l and 358mg/l, respectively. Concentrations of TOC, DOC, NH3-N, Fe and level of colour were also high. In general, the river quality is badly polluted and falls in Class V based on the Malaysian Interim National Water Quality Standards. Event Mean Concentrations (EMC) for various parameters varied considerably between storms. The largest storm produced higher EMC for TSS, NO3-N and SS whereas the smaller storms tend to register higher EMC for BOD, COD, NH3-N, TOC, Ca, K, Mg, Fe and Zn. Such variations could be explained in terms of pollutant availability and the effects of flushing and dilution. Based on a three-month average recurrence interval (ARI) of rainfall, the estimated event loadings (ton/ha) of TSS, BOD, COD, TOC, NH3-N and NO3-N were 0.055, 0.016, 0.012, 0.039, 0.010, 0.0007 and 0.0002, respectively. Heavy metals present in trace quantities. Storms with 3 months ARI could capture about 70% of the total annual loads of major pollutants.
Assessing the cost of groundwater pollution: the case of diffuse agricultural pollution in the Upper Rhine valley aquifer
Authors: Rinaudo J.-D. , Arnal C. , Blanchin R. , Elsass P. , Meilhac A. , Loubier S.
Published: May 2018

This paper presents an assessment of the costs of diffuse groundwater pollution by nitrates and pesticides for the industrial and the drinking water sectors in the Upper Rhine valley, France. Pollution costs which occurred between 1988 and 2002 are described and assessed using the avoidance cost method. Geo-statistical methods (kriging) are then used to construct three scenarios of nitrate concentration evolution. The economic consequences of each scenario are then assessed. The estimates obtained are compared with the results of a contingent valuation study carried out in the same study area ten years earlier.
Nitrogen fluxes on catchment scale: the influence of hydrological aspects
Authors: Zessner M. , Schilling Ch. , Gabriel O. , Heinecke U.
Published: May 2018

In two catchment areas with altogether eight subcatchments characterising different site-specific situations the interaction between anthropogenic activities (e.g. agriculture, nutrition and waste water management), nitrogen emissions and in stream loads as well as concentrations were studied in detail. Groundwater is the most important pathway for nitrogen inputs into surface waters. Denitrification in the soil/subsurface/groundwater system controls the amount of this input to a high extent. Key factors influencing this process are organic carbon availability, geology, precipitation and groundwater recharge rates as well as residence time in groundwater. The MONERIS emission model is a useful tool to quantify these relationships on (sub-)catchment scale. Areas where concentrations in groundwater (e.g. nitrate) tend to be higher due to little dilution with water and might be problematic in respect to limit values for drinking water, are much less relevant in respect to the loads transported to river systems and receiving seas, than regions with high precipitation. In cases with high water availability mainly high loads transported downstream and finally to the receiving sea are a considerable problem. Within a region mainly areas close to river systems contribute to nitrogen discharges to the river system because of the short residence times of the groundwater from these areas and - related to this - a lower influence of denitrification in the groundwater.
BTEX degradation in a cold-climate wetland system
Authors: Wallace S. , Kadlec R.
Published: May 2018

A pilot-scale subsurface vertical-flow wetland system was constructed at the former BP Refinery in Casper, Wyoming in order to determine benzene, toluene, ethylbenzene and xylene (BTEX) degradation rates in a cold-climate application. The pilot system, consisting of 4 cells, each dosed at a nominal flow rate of 5.4 cubic metres per day, was operated between August and December 2002. The pilot tested the effects of wetland mulch and aeration on system performance. Areal rate constants (kA values) were calculated based on an assumed three tanks in series (3TIS). The presence of wetland sod and aeration both improved treatment performance. Mean kA values were 244 m/yr for cells without sod or aeration, and improved to 356 m/yr for cells with sod and aeration. Based on the results of the pilot system, a full-scale wetland system (capable of operating at 6,000 m3/day) was started up in May 2003. The full-scale system achieved permit compliance within one week of startup, but is currently being loaded at only 45% of the design hydraulic load, and 15% of the design BTEX mass load, resulting in a mean kA value of ∼350 m/yr.
Potential of a tropical subsurface constructed wetland to remove phenol from pre-treated pulp and papermill wastewater
Authors: Abira M.A. , van Bruggen J.J.A. , Denny P.
Published: May 2018

The capacity of a pilot project subsurface flow constructed wetland in the tropics to remove phenol from pre-treated pulp and paper mill wastewater was studied under varying hydraulic retention times (HRT) with batch loading. Initial 15 months results indicate that removal efficiencies for phenol were variable but on average reached 60% at 5-day HRT and 77% at 3-day HRT. It was thought that the longer retention time might have caused oxygen and nutrient deficiencies, which may have reduced removal performance. Although phenol was sometimes not detectable in the wetland outflow, on average values over the experimental period did not meet set national guidelines. In the ongoing study, the impact of varying hydraulic retention time and/or loading rate on the removal of phenols will be evaluated and the main removal process established.
Processes in vertical-flow reed beds: nitrification, oxygen transfer and soil clogging
Authors: Kayser K. , Kunst S.
Published: May 2018

Vertical-flow reed beds (VF) with intermittent feeding are extremely reliable regarding aerobic processes. For a save operation with high nitrification rates and without soil clogging it is essential to preserve aerobic conditions in the filter. The challenge is to keep aerobic conditions in the filter without oversizing the system (economical aspects). It is very difficult to determine the current oxygen content in the filters because it ultimately results from complex interactions of a large number of different influencing parameters such as loading rate, degree of clogging, temperature, and hydraulic behaviour of the reed bed. To gain better knowledge of this complex system, different tests and examinations were carried out over several years. Focusing on the questions of identification and the description of conversion and transport processes (water/gas), a full-scale treatment plant under clogged and non-clogged conditions was investigated in detail. Additionally soil column test were carried out. The results make it possible to describe some of the processes and their interactions in the filter body. Recommendations for a safe and controlled operation can be derived.
Quantification of sewer exfiltration using the anti-epileptic drug carbamazepine as marker species for wastewater
Authors: Fenz R. , Blaschke A.P. , Clara M. , Kroiss H. , Mascher D. , Zessner M.
Published: May 2018

The anti-epileptic drug carbamazepine was used as marker species in wastewater to identify and quantify sewer exfiltration. In several studies carbamazepine turned out to be hardly removed in wastewater treatment and not or just slightly attenuated during bank infiltration. Concentrations in wastewater are generally 1000 times higher than the limit of quantification. In contrast to many other marker species a “young” drug as carbamazepine is discharged to the environment only by wastewater. The results from this study carried out in Linz, Austria indicate an average exfiltration rate, expressed as percentage of the dry weather flow that is lost on the city-wide scale, of 1%. This rate is lower than sewage losses reported in most other studies which attempted to quantify exfiltration on the basis of groundwater pollution. However, it was also possible to identify one area with significant higher sewage losses.
Pilot-testing an alternative on-site wastewater treatment system for small communities and its automatic control
Authors: Hong S.-W. , Choi Y.-S. , Kim S.-J. , Kwon G.
Published: May 2018

The pilot test of a new alternative for small wastewater treatment system has been conducted for two years. It consists of a hybrid bioreactor and the expert system including the programmable logic controller and human-machine interface. In order to monitor its status, the real-time data was transferred from the remote station to the central station via a wireless local area network. More efficient and stable performances were observed at automatic operating mode compared with the manual. On an average, COD, SS, T-N and T-P concentrations in the effluent from the hybrid bioreactor were less than 14, 7, 12 and 0.9 mg/L, respectively. According to the result from laboratory experiments, the quality of treated wastewater with chemical coagulation process followed by sand filtration was enough to be utilized again if a final disinfection step is included.
Effluent quality from 200 on-site sewage systems: design values for guidelines
Authors: Charles K.J. , Ashbolt N.J. , Roser D.J. , McGuinness R. , Deere D.A.
Published: May 2018

The quality of effluent from an on-site sewage treatment system is a critical factor in designing the disposal area and, hence, ensuring the sustained performance of the system. Contaminant concentrations in effluent are typically specified in regulatory guidelines or standards; however, the accuracy of these guideline values are brought into question due to the poor performance of septic tanks and the high failure rates of disposal systems reported here and elsewhere. Results from studies of septic tank effluent quality indicated that the effluent is of poorer quality than currently suggested by guidelines. Aerated wastewater treatment systems were found to perform to accreditation guidelines; however, insufficient nutrient data is presently available to assess nutrient loads. It is proposed that the 80th percentile of system performance be adopted as the design value for sizing effluent disposal areas to minimise failure associated with overloading. For septic tanks this equates to 660 mg L−1 SS, 330 mg L−1 BOD, 250 mg L−1 TN and 36 mg L−1 TP.
Evaluating the application of a decision support system in identifying adequate wastewater treatment for small communities. A case study: the Fluvia River Basin
Authors: Alemany J. , Comas J. , Turon C. , Balaguer M.D. , Poch M. , Puig M.A. , Bou J.
Published: May 2018

The identification of adequate wastewater treatment for small communities is a complex problem since it demands a combination of data from different sources, such as aspects of the community and landscape, the receiving environment and the available wastewater treatment technologies. The Catalan Water Agency (Agència Catalana de l'Aigua) considered using an EDSS (Environmental Decision Support System) as a tool to help water managers select the most adequate treatment for the urban wastewater of nearly 3,500 small communities in Catalonia (Spain). From that moment, EDSS was applied to all the river basins in Catalonia. In this paper the authors present the results obtained for the 76 small communities located in one of these river basins: the Fluvia River Basin. The characteristics of the community used in the reasoning process of the EDSS, the list of selected wastewater treatment alternatives, the technical environmental justification for the selected treatments and the reasons for discarding, favouring or disadvantaging them are presented. Finally, some results for the Fluvia River Basin are compared with those obtained in other Catalan river basins with different characteristics in order to evaluate which are the significant features in identifying adequate wastewater treatments.
Nutrient reduction evaluation of sewage effluent treatment options for small communities
Authors: Beavers P.D. , Tully I.K.
Published: May 2018

Small communities that are sewered by either package sewage treatment plants or on-site sewerage facilities are finding that the ground and surface waters are being contaminated. Nitrogen, which typically is not removed in these conventional systems, is a major concern. This project evaluated the capability of four sewage treatment technologies to reduce the amount of nitrogen being discharged in the effluent to the receiving environment. The four sewage treatment processes evaluated include a recirculating sand filter, biofilter, slow sand filter and constructed subsurface flow wetland. These processes were evaluated for their capability to reduce nitrogen, phosphorus, BOD5 and TSS. The primary objective of the project was to evaluate the capability of these treatment processes to reduce nitrogen using biological processes nitrification and denitrification. This paper reports on the performance of these processes to reduce nitrogen. The study demonstrated that the biofilter was capable of removing from a primary treated influent 40% of the total nitrogen. For the same quality influent the recirculating sand filter was capable of removing 35% of the total nitrogen. Secondary treated effluent was fed to the slow sand filter and the subsurface flow wetland. There was a 52% reduction in total nitrogen through the wetland however there was virtually no reduction in total nitrogen through the slow sand filter.
Long-term evolution and trends of the hydrological and hydrochemical parameters in Bulgarian Black Sea waters during the period 1992–2000
Authors: Dineva S.
Published: May 2018

The dynamics of chemical parameters in the Bulgarian Black Sea during the 1990s reflects the complex relations in the ecosystem itself and the influence of the Danube water discharge, which is a major climatic and anthropogenic factor for the Western Black Sea. Analyses of hydrological (temperatures, salinity) and hydrochemical (dissolved oxygen, oxygen saturation, nitrite nitrogen, nitrate nitrogen) data collected during the period 1992–2000 in the 30-miles zone offshore along the Bulgarian Black Sea coast were carried out in the framework of the “DANUBS” project. In the period 1995–2000 gradually the winters were becoming warmer, the springs colder and the summers were short and hot. The long-term averages show spatially a minimum of salinity in front of the Cape Galata at 10 miles offshore, whereas in front of the Cape Emine the salinity increases gradually from the coast towards the 30-miles zone offshore. In the late 1990s very low summer values or even complete absence of inorganic nitrogen in the Bulgarian Black Sea were registered. Seasonally the oxygen varied in broad terms, however on average the surface waters were saturated or slightly oversaturated with oxygen. There was a regular decrease in oxygen concentrations with depth.
Ion exchange with natural zeolites: an alternative for water softening?
Authors: Cinar S. , Beler-Baykal B.
Published: May 2018

Possibility of using natural zeolites for water softening was investigated. Quantitative data regarding separation of calcium from water at various levels of hardness through ion exchange with the ammonium selective natural zeolite clinoptilolite is reported. Capacity of the zeolite towards calcium removal in the presence of ammonium at low concentrations and calcium at higher concentrations, and breakthrough characteristics are presented. The results have revealed that removal of calcium, and hence hardness, through ion exchange with clinoptilolite under those circumstances is a promising alternative, with surface capacities reaching 11 mg calcium/g clinoptilolite.
Changes in waste stabilisation pond performance resulting from the retrofit of activated sludge treatment upstream: part II – management and operating issues
Authors: Sweeney D.G. , O'Brien M.J. , Cromar N.J. , Fallowfield H.J.
Published: May 2018

Bolivar Wastewater Treatment Plant (WWTP) was originally commissioned with trickling filter secondary treatment, followed by waste stabilisation pond (WSP) treatment and marine discharge. In 1999, a dissolved air flotation/filtration (DAFF) plant was commissioned to treat a portion of the WSP effluent for horticultural reuse. In 2001, the trickling filters were replaced with activated sludge treatment. A shift in WSP ecology became evident soon after this time, characterised by a statistically significant reduction in algal counts in the pond effluent, and increased variability in algal counts and occasional population crashes in the ponds. While the photosynthetic capacity of the WSPs has been reduced, the concomitant reduction in organic loading has meant that the WSPs have not become overloaded. As a result of the improvement in water quality leaving the ponds, significant cost savings and improved product water quality have been realised in the subsequent DAFF treatment stage. A number of operating issues have arisen from the change, however, including the re-emergence of a midge fly nuisance at the site. Control of midge flies using chemical spraying has negated the cost savings realised in the DAFF treatment stage. While biomanipulation of the WSP may provide a less aggressive method of midge control, this case demonstrates the difficulty of predicting in advance all ramifications of a retrospective process change.
Virus removal in a pilot-scale ‘advanced’ pond system as indicated by somatic and F-RNA bacteriophages
Authors: Davies-Colley R.J. , Craggs R.J. , Park J. , Sukias J.P.S. , Nagels J.W. , Stott R.
Published: May 2018

Advanced pond systems (APS), incorporating high-rate ponds, algal settling ponds, and maturation ponds, typically achieve better and more consistent disinfection as indicated by Escherichia coli than conventional waste stabilisation ponds. To see whether this superior disinfection extends also to enteric viruses, we studied the removal of somatic phages (‘model’ viruses) in a pilot-scale APS treating sewage. Measurements through the three aerobic stages of the APS showed fairly good removal of somatic phage in the summer months (2.2 log reduction), but much less effective removal in winter (0.45 log reduction), whereas E. coli was removed efficiently (>4 logs) in both seasons. A very steep depth-gradient of sunlight inactivation of somatic phage in APS pond waters (confined in silica test tubes) is consistent with inactivation mainly by solar UVB wavelengths. Data for F-RNA phage suggests involvement of longer UV wavelengths. These findings imply that efficiency of virus removal in APS will vary seasonally with variation in solar UV radiation.
Light attenuation parameters for waste stabilisation ponds
Authors: Heaven S. , Banks C.J. , Zotova E.A.
Published: May 2018

Effective modelling of shallow water ecosystems, including waste stabilisation ponds, is strongly dependent on the availability of good estimates of the light attenuation coefficient k (m−1). Experimental data is presented on its determination using purpose-built laboratory apparatus with a near-parallel halogen light source and an array of photodiodes allowing measurements of irradiance at different depths. The equipment was used to compare k values from 4 different pure cultures, and mixed cultures of algae taken from a pilot-scale WSP. Laboratory values were compared with in situ measurements in the pond. At concentrations above 50 mg l−1 the relationship between k and suspended solids is non-linear; k also varied with depth. This could be modelled by a single equation, suggesting similarity of response in different cultures. At shallow depths and low suspended solids concentrations k values are variable and hard to measure reliably. The results highlight the need to standardise on a method for the measurement and reporting of k values if these are to be widely applicable in the development of pond models.
Optical characteristics of waste stabilization ponds: recommendations for monitoring
Authors: Davies-Colley R.J. , Craggs R.J. , Park J. , Nagels J.W.
Published: May 2018

The optical character of waste stabilization ponds (WSPs) is of concern for several reasons. Algal photosynthesis, which produces oxygen for waste oxidation in WSPs, is influenced by attenuation of sunlight in ponds. Disinfection in WSPs is influenced by optical characteristics because solar UV exposure usually dominates inactivation. The optical nature of WSPs effluent also affects assimilation by receiving waters. Despite the importance of light behaviour in WSPs, few studies have been made of their optical characteristics. We discuss simple optical measures suitable for routine monitoring of WSPs (including at sites remote from laboratories): optical density of filtrates – an index of dissolved coloured organic (humic) matter, visual clarity – to provide an estimate of the beam attenuation coefficient (a fundamental quantity needed for optical modelling) colour (hue) – as an indicator of general WSP ‘condition’ and irradiance attenuation quantifying depth of light penetration. The value of optical characterisation of WSPs is illustrated with reference to optical data for WSPs in NZ (including high-rate algal ponds) treating dairy cattle wastewater versus domestic sewage. We encourage increased research on optical characteristics of WSPs and the incorporation of optical measures in monitoring and modelling of WSP performance
Sustainable management of leakage from wastewater pipelines
Authors: DeSilva D. , Burn S. , Tjandraatmadja G. , Moglia M. , Davis P. , Wolf L. , Held I. , Vollertsen J. , Williams W. , Hafskjold L.
Published: May 2018

Wastewater pipeline leakage is an emerging concern in Europe, especially with regards to the potential effect of leaking effluent on groundwater contamination and the effects infiltration has on the management of sewer reticulation systems. This paper describes efforts by Australia, in association with several European partners, towards the development of decision support tools to prioritize proactive rehabilitation of wastewater pipe networks to account for leakage. In the fundamental models for the decision support system, leakage is viewed as a function of pipeline system deterioration. The models rely on soil type identification across the service area to determine the aggressiveness of the pipe environment and for division of the area into zones based on pipe properties and operational conditions. By understanding the interaction between pipe materials, operating conditions, and the pipe environment in the mechanisms leading to pipe deterioration, the models allow the prediction of leakage rates in different zones across a network. The decision support system utilizes these models to predict the condition of pipes in individual zones, and to optimize the utilization of rehabilitation resources by targeting the areas with the highest leakage rates.
Reduction of odors from a facultative pond using two different operating practices
Authors: Truppel A. , Camargos J.L.M. , da Costa R.H.R. , Filho P. Belli
Published: May 2018

This paper presents the results of a proposed intervention to deal with the odor problems of a sewage treatment works (STW), which is located near a populated area. The STW consists of a facultative pond. Since this pond functions under close to anaerobic conditions, unpleasant odors are emitted. In this respect, two possible ways to deodorize the pond were evaluated. Firstly, the recirculation of effluent using 1/6 of the flow stream followed by aeration of the pond with a reduced power aerator. In order to study the efficiencies of the deodorization methodologies chemical analyses of the gases NH3 and H2S, olfactometric analyses and evaluation of the environmental perception of the population in relation to the odors originating from the STW, were carried out for each experimental situation. The results showed a significant reduction in odors when aeration with reduced power equipment was utilized in combination with recirculation of effluent in the pond. Reductions in emissions of H2S from 0.1345 mg/m3 to 0.0083 mg/m3 and of NH3 from 0.021 mg/m3 to 0.0073 mg/m3 were obtained. To analyze the behavior of the pond, its planktonic community was investigated, with a difference in species for the situations with and without odor being observed.
A new installation for treatment of road runoff: up-flow filtration by porous polypropylene media
Authors: Lee B.C. , Matsui S. , Shimizu Y. , Matsuda T. , Tanaka Y.
Published: May 2018

We installed a new device on a paved road to treat runoff from a roadway surface. All the stormwater runoff was transferred into the device and the runoff equivalent to 10mm/hr or less was treated. The treatment method consists of sedimentation and up-flow filtration with porous polypropylene (PPL) processes. The treated runoff was discharged into the existing storm drainage pipe. The average removal efficiency of the initial runoff at the beginning of rainfall which has high pollution intensity was about 90% for SS, about 70% for COD, about 40% for total phosphorus (T-P), about 80% for Pb and Cd, about 70% for Zn, Cu, Mn and Cr, and about 60% for polycyclic aromatic hydrocarbons (PAHs). The overall removal efficiencies of the experiment that ran for four months remained >60% of SS, >40% of COD, >60% of heavy metals, and >40% of PAHs. The PPL is excellent for removing smaller size particulates of suspended solids, which originate basically from diesel exhaust, as well as larger size particulates from automobile tires, asphalt roads, and other accumulated source(s) of clay and sand, etc.
Isolation of Salmonella sp. in sludge from septage treatment plant
Authors: Sanguinetti G.S. , Ferrer V. , García M.C. , Tortul C. , Montangero A. , Koné D. , Strauss M.
Published: May 2018

Waste stabilization ponds (WSP) are an often-used option to treat faecal sludges collected from on-site sanitation systems. Since agricultural use is one of the most attractive options for sludge disposal, specific guidelines on the hygienic sludge quality must be fulfilled, such as for viable helminth eggs and Salmonella sp. Although Salmonella isolation methods are well known for other types of samples, they are not suitable for faecal sludge. The reason can be attributed to the co-existence of a native bacterial sludge flora masking Salmonella development, especially if this bacteria is present at low concentrations. In order to select the best methodology for Salmonella recovery from septage sludge, different culture media were assayed at different incubation periods and temperatures. The proposed methodology for Salmonella recovery from sludge can be summarised as follows: (1) enrichment in Rappaport-Vassiliadis broth at 43°C, 48 hours, and (2) isolation in XLD agar at 40°C, 24 hours. Identification of suspected colonies by biochemical tests: TSI, LIA, urease and serological confirmation with Group O Antigen.
Development of on-site fish exposure system placed in water quality monitoring stations along a river
Authors: Higashitani T. , Miyajima K. , Nakada N. , Yasojima M. , Tanaka H. , Suzuki Y.
Published: May 2018

Estrogen-like substances have been suspected to cause feminization of wild fish in rivers in Japan. To elucidate the influence of estrogen-like substances on fish in river, we have started to develop the on-site continuous fish exposure system using medaka Oryzias latipes that were placed in water quality monitoring stations along a river. Adult male medaka were exposed to the river water in a glass exposure tank placed in the monitoring stations. Flow rate of water and water temperature were controlled at 30L/hour and 26°C respectively, and a light: dark cycle was maintained 16:8 hours. A commercial diet free from phyto-estrogens was fed 4 times in a day using automatic feeder. After 2-week exposure, hepatic vitellogenin concentration of each male medaka was measured. The exposure tests were repeatedly performed at both the upstream and the downstream of sewage treatment plants along the River Tama which is a representative urbanized river in Japan. At the control site Haijimabashi monitoring station, vitellogenin was not detected in male medaka. On the other hand, at the Ishihara monitoring station which is the most downstream in this test area, every male medaka were produced vitellogenin in the test performed in the spring of 2004. As the results of the water quality analysis, it could be inferred that the estrone derived from effluents of sewage treatment plants caused the feminization of male medaka. The reason why the concentrations of the estrone and the estrogenic activity using DNA recombinant yeast varied in proportion to the electric conductivity of river water measured at the water quality monitoring station. Furthermore, after continuous 2-week exposure, the vitellogenin production of male medaka was reduced similar to the decrease of the concentrations of the estrone and the estrogenic activity of river water.
Integrated natural treatment systems for developing communities: low-tech N-removal through the fluctuating microbial pathways
Authors: Shipin O. , Koottatep T. , Khanh N.T.T. , Polprasert C.
Published: May 2018

Integration of natural treatment systems (NTS) (WSP, wetlands etc.) with each other as well as with advanced unit processes (biofiltration) offers a second lease of life to NTS. Long-term full and pilot scale experience in South Africa and Thailand have shown that contrary to a common view, a low tech N-removal from municipal and light industrial wastewater is a reality for a developing community The high treatment efficiency is ascribed to interplay of N-related processes complementing each other. The present FISH-based (Fluorescence In Situ Hybridization) approach to microbial community structure is a pioneering effort in the field of NTS. It establishes interrelationships between major N-removing groups (aerobic and anaerobic ammonia oxidizers (ANAMMOX), denitrifiers) within integrated systems and links them to the high treatment performance. Seasonally fluctuating presence of the ANAMMOX bacteria (0–2.5% of total bacterial numbers) in the NTS (free surface flow wetland) is reported for the first time. Their numbers correlate with metabolically dependent ammonia-oxidizers (2.0–3.0%) but not with stable overall Planctomycetes population (4.5–5.1%). As a result of the flexible microbial structure the robust low cost removal down to TN <10 mg/L is routinely feasible at the loading rates ranging from 0.005 to 0.08 TN kg/m3/day.
Behavior of cellulose-degrading bacteria in thermophilic anaerobic digestion process
Authors: Syutsubo K. , Nagaya Y. , Sakai S. , Miya A.
Published: May 2018

Previously, we found that the newly isolated Clostridium sp. strain JC3 became the dominant cellulose-degrading bacterium in thermophilic methanogenic sludge. In the present study, the behavior of strain JC3 in the thermophilic anaerobic digestion process was investigated quantitatively by molecular biological techniques. A cellulose-degrading experiment was conducted at 55 °C with a 9.5 L of anaerobic baffled reactor having three compartments (Nos. 1, 2, 3). Over 80% of the COD input was converted into methane when 2.5 kgCOD m−3 d−1 was loaded for an HRT of 27 days. A FISH probe specific for strain JC3 was applied to sludge samples harvested from the baffled reactor. Consequently, the ratio of JC3 cells to DAPI-stained cells increased from below 0.5% (undetectable) to 9.4% (compartment 1), 13.1% (compartment 2) and 21.6% (compartment 3) at day 84 (2.5 kgCOD m−3 d−1). The strain JC3 cell numbers determined by FISH correlated closely with the cellulose-degrading methanogenic activities of retained sludge. A specific primer set targeting the cellulase gene (cellobiohydrolaseA: cbhA) of strain JC3 was designed and applied to digested sludge for treating solid waste such as coffee grounds, wastepaper, garbage, cellulose and so on. The strain JC3 cell numbers determined by quantitative PCR correlated closely with the cellulose-sludge loading of the thermophilic digester. Strain JC3 is thus important in the anaerobic hydrolysis of cellulose in thermophilic anaerobic digestion processes.
Analysis of community structures in anaerobic processes using a quantitative real-time PCR method
Authors: Yu Y. , Lee C. , Hwang S.
Published: May 2018

The methanogenic community structures of four different anaerobic processes were characterized using a quantitative real-time PCR with group-specific primer and probe sets targeting the 16S rRNA gene (rDNA). The group specific primer and probe sets were developed and used to detect the orders Methanosarcinales, and the families Methanosarcinaceae and Methanosaetaceae. Two separate sets targeting the domains Archaea and Bacteria were also used. Each microbial population in different anaerobic processes was determined and the relative abundance in the system was compared with each other. Dominant methanogenic populations and the community structures in the processes were varied by hydraulic retention time and acetate concentration. This indicates that the real-time PCR method with the primer and probe sets is a promising tool to analyze community structures in anaerobic processes.
Molecular analysis of Desulfitobacterium frappieri  pcp-1 involved in reductive dehalogenation of pentachlorophenol
Authors: Villemur R. , Beaudet R. , Lanthier M. , Gauthier A. , Boyer A. , Thibodeau J. , Lépine F. , Duguay M. , Pagé-Bélanger R.
Published: May 2018

Desulfitobacterium are Gram positive, spore-forming, strictly anaerobic bacteria, that belong to the Firmicutes, Clostridia, Clostridiales, and Peptococcaceae. Most known members of the genus Desulfitobacterium have the ability to dechlorinate several halogenated compounds by a mechanism of reductive dehalogenation and use them as electron acceptors to generate energy (halorespiration). Desulfitobacteria are therefore perfect candidates to be used in bioremediation treatments of environment polluted with halogenated compounds. Understanding the physiology and the molecular mechanisms of these bacteria will help to develop better bioremediation systems. This report summarizes works that have been done in our laboratories with D. frappieri PCP-1 on reductive dehalogenases, genes encoding these dehalogenases and their expression, and the development of lab-scale PCP-degrading reactors using this bacterium.
Start-up of bio-hydrogen production reactor seeded with sewage sludge and its microbial community analysis
Authors: Gong M.L. , Ren N.Q. , Xing D.F.
Published: May 2018

Start-up of a continuously stirred tank reactor for bio-hydrogen production under different initial organic loading rate (OLR) of 3, 7 and 10 kgCOD/m3 d, respectively, was carried out with sewage sludge as inoculum. Molasses wastewater was used as substrate and hydraulic retention time was kept at 6 h. This study aimed to assess OLR on the formation of fermentation types and the structure of microbial communities during the start-up period. It was found that at an initial OLR of 7 kgCOD/m3 d and an initial biomass of 6.24 gVSS/L, an equilibrial microbial community of ethanol-type fermentation could be established within 30 days. The observed average specific hydrogen production rate was 276 mLH2/gVSS d, which was 40% higher than that of the one acclimated with 3 kgCOD/m3 d. Based on denaturing gradient gel electrophoresis profiles, significant microbial population shifts took place at the first 15 days, but a longer period up to 30 days was required to establish a microbial community with stable metabolic activity.
Influences of pH and hydraulic retention time on anaerobes converting beer processing wastes into hydrogen
Authors: Lay J.J. , Tsai C.J. , Huang C.C. , Chang J.J. , Chou C.H. , Fan K.S. , Chang J.I. , Hsu P.C.
Published: May 2018

To convert high-solids organic wastes (3% w./w.) to high-value hydrogen, a full factorial experimental design was employed in planning the experiments for learning the effects of pH and hydraulic retention time (HRT) on the hydrogen production in a chemostat reactor using waste yeast obtained from beer processing wastes. For determining which experimental variable settings affect hydrogen production, predictive polynomial quadratic equation and response surface methodology were employed to determine and explain the conditions required for high-value hydrogen production. Experimental results indicate that a maximum hydrogen production rate of 460 mL/gVSS/d was obtained at pH=5.8 and HRT=32 hours. Moreover, hydrogenase targeted RT-PCR results indicate that Clostridium thermocellum and Klebsiella pneumoniae predominated.
Fermentative hydrogen production in a system using anaerobic digester sludge without heat treatment as a biomass source
Authors: Shizas I. , Bagley D.M.
Published: May 2018

Hydrogen produced from anaerobic fermentation of organic matter is a sustainable energy source. Anaerobic hydrogen-producing systems have been typically seeded with heat-treated inocula to eliminate hydrogen-consuming methanogens. This can be both energy- and economically-intensive. In this work, operational parameters were modified to determine if operating a reactor at low pH (5.5) and low SRT (10 hours) would result in a hydrogen-producing system free of methanogens using anaerobic digester sludge with no heat treatment as an inoculum. Initially, the reactor exhibited a hydrogen productivity of approximately 7.9% when fed glucose. After purging was begun with 10% CO2/90% N2, the hydrogen productivity increased to >20% for the first day. Hydrogenotrophic methanogens then established themselves in the reactor, reducing the hydrogen productivity in the second non-purged phase by 80%. The operational controls examined were not sufficient to eliminate hydrogen-consuming methanogens for longer than approximately one week, and thus further methods must be developed.
Thermal pre-treatment of primary and secondary sludge at 70 °°C prior to anaerobic digestion
Authors: Skiadas I.V. , Gavala H.N. , Lu J. , Ahring B.K.
Published: May 2018

In general, mesophilic anaerobic digestion of sewage sludge is more widely used compared to thermophilic digestion, mainly because of the lower energy requirements and higher stability of the process. However, the thermophilic anaerobic digestion process is usually characterised by accelerated biochemical reactions and higher growth rate of microorganisms resulting in an increased methanogenic potential at lower hydraulic retention times. Furthermore, thermal pre-treatment is suitable for the improvement of stabilization and could be realized at relatively low cost especially at low temperatures. The present study investigates the effect of the pre-treatment at 70 °C on thermophilic (55 °C) anaerobic digestion of primary and secondary sludge in continuously operated digesters. Thermal pre-treatment of primary and secondary sludge at 70 °C enhanced the removal of organic matter and the methane production during the subsequent anaerobic digestion step at 55 °C. It also greatly contributed to the destruction of pathogens present in primary sludge. Finally it results in enhanced microbial activities of the subsequent anaerobic step suggesting that the same efficiencies in organic matter removal and methane recovery could be obtained at lower HRTs.
Oxidative and thermo-oxidative co-treatment with anaerobic digestion of excess municipal sludge
Authors: Cacho Rivero J.A. , Madhavan N. , Suidan M.T. , Ginestet P. , Audic J.-M.
Published: May 2018

The effect of oxidative and thermo-oxidative co-treatment of excess municipal sludge was investigated. A mixture of primary and waste activated sludge was anaerobically treated using two different configurations: i) two stages and ii) a single stage with recycling. Oxidative or thermo-oxidative co-treatment placed in between the reactor or in the recycle line was studied. A two-stage configuration with no co-treatment served as a control and resulted in 50.1% overall solids removal. Compared to the control, an increase in solids removal of 10.8 and 2.7% was observed when oxidative co-treatment was placed between reactors and in the recycle line respectively. When thermo-oxidative co-treatment was placed between the two stages or in the recycle line an increase in solids removal of 25.1 and 26.9% respectively was observed. The performances of the different configurations were also evaluated with parameters such as COD, TKN, ammonia, and fecal coliform concentration.
Membrane-coupled anaerobic digestion of municipal sewage sludge
Authors: Pierkiel A. , Lanting J.
Published: May 2018

Membrane-coupled anaerobic digestion utilizes a concept of simultaneous sludge digestion and thickening. Membranes may successfully be applied to eliminate the need for thickening polymers and avoid their likely inhibitory effect on anaerobic biomass. A 550 L completely mixed anaerobic digester was operated under mesophilic conditions (35 °C). Two ultrafiltration membrane systems were evaluated for their potential in membrane-coupled anaerobic digestion: vibrating and cross flow. A volatile solids reduction of 59% was achieved at an average mixed liquor suspended solids concentration of 1.8%. The substrate utilization rate was 1.3 d−1. The vibrating membrane operated at a flux of 1.6–2.0 m3/m2-d and the tubular membrane fluxes in the range 3.4–3.6 m3/m2-d.
Effect of biological additives and micronutrients on the anaerobic digestion of physicochemical sludge
Authors: Noyola A. , Tinajero A.
Published: May 2018

Two additives (lyophilized bacilli and enzymes) and a solution of micronutrients (Fe, Co, Ni and Mo) were tried separately and in combination, in order to assess their effect on the anaerobic digestion of waste sludge from an enhanced primary treatment (EPT) of municipal wastewater. Three batch tests were carried out in serological bottles. In the first test, addition of bacilli increased production of methane from day 11 and at day 17 the production was 95% greater than the control. In that experiment, the concentration of volatile fatty acids (VFAs) was 1,391 mg/L, 40% lower than the control. In the second test, the combination of micronutrients with bacilli, reached from the first days a better methane production than the control, 167% higher in day 17. At the end of the experiment, this combination achieved a lower concentration of VFAs and a greater percentage of volatile solid removal than the rest of the treatments. The third test was based on an experimental design in order to statistically determine the best doses of bacilli additive and micronutrients. The anaerobic thermophilic digestion of sludge from aluminium sulfate EPT will be improved with the addition of Fe: 4.5 mg/g VS, Ni: 0.75 mg/g VS, Co: 0.45 mg/g VS, Mo: 0.09 mg/g VS and bacilli additive: 12 mg/g VS.
Phosphate inhibition on thermophilic acetoclastic methanogens: a warning
Authors: Paulo P.L. , dos Santos A.B. , Ide C.N. , Lettinga G.
Published: May 2018

The inhibitory effect of phosphate on acetoclastic-methanogens was investigated for three different thermophilic (55 °C) anaerobic consortia. When 70 mM of phosphate was tested, acetoclastic methanogens was completely inhibited in “Eerbeek” sludge which is dominated by Methanosaeta-like methanogens. For the “Hoogezand” sludge the specific methanogenic activity dropped by 79%, indicating that any of the acetate-consuming methanogens present in the sludge was more resistant to the phosphate applied. The results demonstrated that the inhibitory effect of phosphate may affect both methane production rate and final methane concentration and might also be time dependent. This study indicates that the degree of inhibition is species-dependent, and even more resistant species may be affected during long-term experiments. Such inhibition is a matter of concern for researchers since misleading conclusions might be taken from growth and specific methanogenic activity tests when considerable concentrations of phosphate buffer are used and no interference is expected.
Treatment of a low concentration industrial chemicals mixture in an UASB reactor
Authors: Castilla P. , Leyva A. , García U. , Monroy O. , Meraz M.
Published: May 2018

A wastewater containing a mixture of methanol, isopropyl alcohol, ethylene glycol, acetic anhydride, methyl, ethyl and isopropyl acetate, acrylic acid, butyl and methyl acrylate, o, m and p-xylene and styrene was fed to an UASB reactor. Isopropanol addition diminished the removal efficiency to 60% and required a long adaptation time for its total mineralization. When acrylic acid was added to the mixture, the removal dropped to 83% and recovered after 40 days. As for the rest of the substrates, p-m-o-xylene addition had no effect on reactor performance, although in batch assays it showed low mineralization. Also the effect of volumetric organic load on removal efficiency was followed up. After diminishing the HRT to 4 and 3 h yielding 4.8 and 6.5 gCOD L−1 d−1, removal efficiencies decreased to 79 and 74% respectively.
Phenolic refinery wastewater biodegradation by an expanded granular sludge bed reactor
Authors: Almendariz F.J. , Meraz M. , Olmos A.D. , Monroy O.
Published: May 2018

Refinery spent caustics (SC) were diluted with sour waters (SW) in a ratio 1:7, neutralized with CO2 (SC/SWCO2) and 83% of H2S was striped during this procedure, remaining an aromatic portion that contained 2123, 2730 and 1379 mg L−1 of phenol, p-cresol and o-cresol, respectively. The mixture was treated anaerobically in an EGSB reactor fed with 1.5 gCOD L−1 d−1, without mineral supplements causing loss of COD removal efficiency that dropped to 23%, methane production ceased and no phenol or cresols were biodegraded. The EGSB experiments were resumed by feeding the reactor with nutrients and phenol at 1.0 gCOD L−1 d−1. The mixture SC/SWCO2 added to the phenol load, was step increased from 0.10 to 0.87 gCOD L−1 d−1 maximum. When total organic load was increased to 1.6, COD removal efficiency was 90% and at the highest load attained, 1.87, efficiency dropped to 23% attributed to the toxic effect produced by cresols.
Robust interval-based regulation for anaerobic digestion processes
Authors: Alcaraz-González V. , Harmand J. , Rapaport A. , Steyer J.P. , González-Álvarez V. , Pelayo-Ortiz C.
Published: May 2018

A robust regulation law is applied to the stabilization of a class of biochemical reactors exhibiting partially known highly nonlinear dynamic behavior. An uncertain environment with the presence of unknown inputs is considered. Based on some structural and operational conditions, this regulation law is shown to exponentially stabilize the aforementioned bioreactors around a desired set-point. This approach is experimentally applied and validated on a pilot-scale (1 m3) anaerobic digestion process for the treatment of raw industrial wine distillery wastewater where the objective is the regulation of the chemical oxygen demand (COD) by using the dilution rate as the manipulated variable. Despite large disturbances on the input COD and state and parametric uncertainties, this regulation law gave excellent performances leading the output COD towards its set-point and keeping it inside a pre-specified interval.