bluuebunny/crossref_metadata_2025 huggingface dataset:
Liquid waste management strategies for coastal areas
Authors: Alpaslan M.N. , Dölgen D. , Akyarli A.
Published: May 2018

Liquid waste management in coastal areas is a challenging issue, because recipe solutions applied so far have not met the expectations fully. Therefore decision-makers, planners, engineers as well as the inhabitants of these places are looking for a better approach that will adequately handle the problem and perform reliable solutions. It is the aim of this paper to review the recent situation of liquid waste management for coastal areas in general, and discuss it from the point of view of Turkey in particular. A simple and applicable waste management strategy is also proposed in the paper and its merits are illustrated in a case study. Finally, anticipating the wide applications of such systems in coastal establishments, some recommendations are forwarded.
Nitrate in aquifers beneath agricultural systems
Authors: Burkart M.R. , Stoner J.D.
Published: May 2018

Research from several regions of the world provides spatially anecdotal evidence to hypothesize which hydrologic and agricultural factors contribute to groundwater vulnerability to nitrate contamination. Analysis of nationally consistent measurements from the U.S. Geological Survey’s NAWQA program confirms these hypotheses for a substantial range of agricultural systems. Shallow unconfined aquifers are most susceptible to nitrate contamination associated with agricultural systems. Alluvial and other unconsolidated aquifers are the most vulnerable and shallow carbonate aquifers provide a substantial but smaller contamination risk. Where any of these aquifers are overlain by permeable soils the risk of contamination is larger. Irrigated systems can compound this vulnerability by increasing leaching facilitated by additional recharge and additional nutrient applications. The agricultural system of corn, soybeans, and hogs produced significantly larger concentrations of groundwater nitrate than all other agricultural systems, although mean nitrate concentrations in counties with dairy, poultry, cattle and grains, and horticulture systems were similar. If trends in the relation between increased fertilizer use and groundwater nitrate in the United States are repeated in other regions of the world, Asia may experience increasing problems because of recent increases in fertilizer use. Groundwater monitoring in Western and Eastern Europe as well as Russia over the next decade may provide data to determine if the trend in increased nitrate contamination can be reversed. If the concentrated livestock trend in the United States is global, it may be accompanied by increasing nitrogen contamination in groundwater. Concentrated livestock provide both point sources in the confinement area and intense non-point sources as fields close to facilities are used for manure disposal. Regions where irrigated cropland is expanding, such as in Asia, may experience the greatest impact of this practice.
Runoff characteristics of pesticides from paddy fields and reduction of risk to the aquatic environment
Authors: Ebise S. , Inoue T.
Published: May 2018

Simultaneous rice-transplanting and subsequent application of pesticides to the paddy fields in the catchment of a rural river on weekends from late May to mid June caused high concentrations and high loadings of pesticides in the river. Imperfections in irrigation water management and the overflow discharge from paddy fields during heavy storm events increased the risk of drinking water contamination and threatened the aquatic ecosystems. Several pesticides were detected at nearly ten ppb in the biofilms on the river bed. In order to reduce the risks due to runoff pesticides, it is necessary to improve the management of irrigation and to strengthen the biodegradation capacity of biofilms on the river bed by maintaining a long retention time in drainage channels.
Nitrate leaching from construction sites to groundwater in the Nottingham, UK, urban area
Authors: Wakida F.T. , Lerner D.N.
Published: May 2018

Nitrate pollution has been identified as a major water quality issue in the UK. The aim of this project is to research the rate of nitrate leaching to groundwater that arises from construction works. The study area is situated in Nottingham UK, which is situated on the Triassic Sandstone aquifer. Soil samples up to a depth of 2.50 m were taken from three sites under construction and other land use. The results have shown a high variability in the concentrations of soil-nitrate. The reasons for this variability include soil type, past land use, soil treatment and type of vegetation prior to construction works. The average nitrogen load was 65 kg N ha−1 which is higher than the nitrate leaching observed when temporary grassland is ploughed during autumn. The highest nitrate concentrations were observed in an allotment site (133 kg N ha−1) due to the high amount of manure applied at this location. The construction practice of top soil stripping can produce a reduction of nitrate leaching because it removes the part of the soil that contains most of the potentially mineralizable nitrogen.
Comparison of the pollutant loads in dry and wet weather runoff in a southern California urban watershed
Authors: McPherson T.N. , Burian S.J. , Turin H.J. , Stenstrom M.K. , Suffet I.H.
Published: May 2018

This research compares the relative contributions of potential contaminants discharged in dry weather flow (DWF) and wet weather flow (WWF) from the highly urbanized Ballona Creek watershed (BCW) in southern California using empirical and deterministic models. These models were used to compare the loading of the following pollutants: total suspended solids, biochemical oxygen demand, total nitrogen, total inorganic nitrogen, total Kjeldahl nitrogen, total phosphorus, copper, lead, arsenic, nickel, cadmium, and chromium. The results indicate DWF contributes approximately 10–30% of the total annual flow discharged from Ballona Creek. The annual DWF volume was fairly consistent; the variation in DWF percentage contribution was dependent on the highly variable volume of WWF. The relative contribution to the annual pollutant load varied considerably between each pollutant. In general, the DWF load was found to be significant, especially in years with lower precipitation totals. The results from this investigation have identified the relative relationship between DWF and WWF loads in the BCW and will aid in the decision-making process during the development of an integrated DWF-WWF management plan and allocation of water pollution control funds between DWF and WWF management.
Removal of organics and nitrogen in sewage treatment using anoxic-aerobic recirculated filter
Authors: Tanaka S. , Suzuki A.
Published: May 2018

The anoxic-aerobic recirculated filter (AARF) process was investigated on removal effciencies of organics and nitrogen with regard to loading rates, recirculation ratios of nitrified liquor and contribution of methane production and sulfate reduction in the treatment of the municipal sewage. The AARF process is composed of an anoxic filter for denitrification and an aerobic filter for nitrification and some of the nitrified liquor in the aerobic filter is recirculated to the anoxic filter. The AARF process successfully removed organics and nitrogen achieving high removal rates of 88% for COD and 64-74% for nitrogen. The recirculation ratio (Re) did not affect the COD removal efficiency but did affect the nitrogen removal, which was enhanced at a higher ratio (Re = 4). The methane production was not contributive to the COD removal but the COD consumed by the sulfate reduction was equivalent to 17% of total COD removed at Re = 2. We confirmed that the AARF process was applicable to the sewage treatment including nitrogen removal at a hydraulic retention time close to that of the conventional activated sludge process.
Evaluation of thermophilic anaerobic microbial consortia using fluorescence in situ hybridization (FISH)
Authors: Domingues M.R. , Araujo J.C. , Varesche M.B.A. , Vazoller R.F.
Published: May 2018

In this study we investigated the development of anaerobic biofilms in differential reactors and suspension cultures in batch reactors under thermophilic (55°C) conditions. FISH, SEM, chemical and chromatographic analysis were used. The differential reactors reached 99.6%, 92.3% and 6.7% of acetic acid, COD and sulfate removal efficiencies, respectively, after 166 h of incubation time. The batch reactor reached 95.6% and 31.8% of acetic acid and sulfate removal efficiencies after 675 h, respectively. FISH results showed that bacterial cells rather than archaeal cells dominated biofilms. These cells, detected with the Bacteria specific probe (EUB338), accounted for 61.1% (±3.6) of the DAPI-stained cells and resembled acetate-oxidizing rods and Desulfotomaculum morphologies. Archaeal cells, which hybridized to the Archaea specific probe (ARC915), were also detected in biofilm but they accounted for 36.7% (±2.9) of the DAPI-stained cells. These cells were similar to Methanosaeta-like and hydrogenotrophic methanogen rods. In the suspension culture, archaeal cells (58.0% ± 3.8) morphologically similar to Methanosarcina and hydrogenotrophic methanogen rods were predominant over bacterial cells (41.0% ± 4.5), which resembled acetate-oxidizing rods and Desulfotomaculum morphologies. The percentage of sulfate-reducing bacteria cells (SRB) ranged from 12.2% (±2.5) to 21.7% (±2.8) in the biofilms and from 13.3% (±3.6) to 21.7% (±4.3) of the DAPI stained cells in suspension culture.
Reductive biodegradation of 1,2-dichloroethane by methanogenic granular sludge: perspectives for in situ remediation
Authors: De Wildeman S. , Nollet H. , Van Langenhove H. , Diekert G. , Verstraete W.
Published: May 2018

Granular methanogenic sludge was able to dechlorinate 1,2-dichloroethane (1,2-DCA) to ethene in UASB reactors. Ethanol served as the sole carbon and energy source. The average dechlorination rate measured on the basis of ethene production varied between 1.7 and 2.1 μmol 1,2-DCA/(h.gVSS) (46.7 and 57.4 mg/L.d). In order to elucidate the microbial origin of this bioconversion, enrichment cultures of the methanogenic sludge were prepared with different carbon and electron sources: pyruvate, lactate, H2/CO2, ethanol and formate. Dithiothreitol (DTT) was the strong reductant in order to increase the negative redox potential in the media. A homo-acetogenic gram-positive strain could be isolated in the presence of formate. 16S rRNA of the isolated strain showed that the bacterium was closely related (99.7%) to Acetobacterium wieringae. The strain also grew on pyruvate, lactate, H2/CO2 and ethanol, although dechlorination rates of 1,2-DCA were at least 5 times higher when formate was the (only) electron source. Average conversion rates reached 3 μmol/(h.gdry cells) and appeared to relate to cometabolic biocatalysis on the corrinoid centers of the homo-acetogenic strain. Some perspectives of anaerobic in situ bioremediation of groundwater polluted with chloroethanes are presented.
The AF-BNR-SCP process as a way to reduce global sludge production: comparison with classical approaches on a full scale basis
Authors: Battistoni P. , Pezzoli S. , Bolzonella D. , Pavan P.
Published: May 2018

The paper presents a comparison between the performances of two full scale wastewater treatment plants operating in Italy, considering the mass balances including P treatments, and results coming from an analysis of 16 similar plants in Europe and USA, in order to evaluate sludge overproduction due to chemical P removal adoption. Specific production of 9.5 and 12.5 kgTS/P.E.y were found for a BNR and denitrification plant scheme respectively. These results were compared, on a mass balance basis, with the performances coming from the adoption of the integrated waste/wastewater cycles, in which OFMSW fermentation is used as C source to promote BNR performances and P removal from anaerobic supernatants as struvite crystals. ASM2 simulations are used to verify the advantages coming from this approach in terms of sludge reduction. A complete mass balance of the process is carried out, and it is shown that this last process allows us to achieve the lowest sludge production among the processes considered, coupling this with the economic benefits coming from OFMSW disposal and struvite crystallisation.
The influence of calcium on granular sludge in a full-scale UASB treating paper mill wastewater
Authors: Batstone D.J. , Landelli J. , Saunders A. , Webb R.I. , Blackall L.L. , Keller J.
Published: May 2018

Calcium precipitation can have a number of effects on the performance of high-rate anaerobic performance including cementing of the sludge bed, limiting diffusion, and diluting the active biomass. The aim of this study was to observe the influence of precipitation in a stable full-scale system fed with high-calcium paper factory wastewater. Granules were examined from an upflow anaerobic sludge blanket reactor (volume 1,805 m3) at a recycled paper mill with a loading rate of 5.7–6.6 kgCOD.m−3.d−1 and influent calcium concentration of 400–700 gCa.m−3. The granules were relatively small (1 mm), with a 200–400 μm core of calcium precipitate as observed with energy dispersive X-ray spectroscopy. Compared to other granules, Methanomicrobiales not Methanobacteriales were the dominant hydrogen or formate utilisers, and putative acidogens were filamentous. The strength of the paper mill fed granules was very high when compared to granules from other full-scale reactors, and a partial linear correlation between granule strength and calcium concentration was identified.
Treatment of winery wastewater by an anaerobic sequencing batch reactor
Authors: Ruíz C. , Torrijos M. , Sousbie P. , Lebrato Martínez J. , Moletta R. , Delgenès J.P.
Published: May 2018

Treatment of winery wastewater was investigated using an anaerobic sequencing batch reactor (ASBR). Biogas production rate was monitored and permitted the automation of the bioreactor by a simple control system. The reactor was operated at an organic loading rate (ORL) around 8.6 gCOD/L.d with soluble chemical oxygen demand (COD) removal efficiency greater than 98%, hydraulic retention time (HRT) of 2.2 d and a specific organic loading rate (SOLR) of 0.96 gCOD/gVSS.d. The kinetics of COD and VFA removal were investigated for winery wastewater and for simple compounds such as ethanol, which is a major component of winery effluent, and acetate, which is the main volatile fatty acid (VFA) produced. The comparison of the profiles obtained with the 3 substrates shows that, overall, the acidification of the organic matter and the methanisation of the VFA follow zero order reactions, in the operating conditions of our study. The effect on the gas production rate resulted in two level periods separated by a sharp break when the acidification stage was finished and only the breaking down of the VFA continued.
Co-digestion of domestic kitchen waste and night soil sludge in a full-scale sludge treatment plant
Authors: Yoneyama Y. , Takeno K.
Published: May 2018

A study was made on the domestic kitchen waste and night soil treatment performance of a full-scale sludge treatment plant. The sludge treatment at this plant was by thermophilic methane fermentation. The initial treatment, mesophilic to thermophilic fermentation, was able to be started up within a short time by adjusting the amount of influent waste. Thermophilic methane fermentation was carried out for five months (May–October) and the performance under a mean residual time of 22 days indicated a VTS decomposition of 42%, gas generation of 54–1,610 m3/day (average: 755 m3/day), and a mean methane concentration of 60%. The methane gas was used to generate power in the plant and the amount of power generated by methane gas was highest in October (average of 1,200 kWh/day). This was equivalent to about 7% of the power consumed at the entire sludge treatment plant. The BOD/NH4-N of the activated sludge influent water was lower, compared to a case where there is no recycle flow, due to the recycle flow from the methane fermentation process. There was, therefore, a tendency for an increase in the amount of methanol charged into the secondary denitrification tank. However, the quality of the effluent was satisfactory (BOD< 10 mg/L, SS< 5 mg/L, and T-N< 25 mg/L). Study results indicated that it was possible to implement a full-scale plant for recovering organic waste.
The challenge of faecal sludge management in urban areas - strategies, regulations and treatment options
Authors: Ingallinella A.M. , Sanguinetti G. , Koottatep T. , Montangero A. , Strauss M.
Published: May 2018

In urban centres of industrialising countries, the majority of houses are served by on-site sanitation systems such as septic tanks and unsewered toilets. The faecal sludges (FS) collected from these systems are usually discharged untreated into the urban and peri-urban environment, posing great risks to water resources and to public health. Contrary to wastewater management, the development of strategies to cope with faecal sludges, adapted to the conditions prevailing in developing countries, have long been neglected. The authors describe the current situation and discuss selected issues of FS management. A proposal is made for a rational setting of sludge quality or treatment standards in economically emerging countries. The authors stipulate that regulatory setting should take into account local economic, institutional and technical conditions. Defining suitable treatment options as critical control points in securing adequate sludge quality is better than setting and relying on numerical sludge quality standards. A separate section is devoted to the practice and to regulatory aspects of (faecal) sludge use in Argentina. An overview of treatment options, which may prove sustainable in less industrialized countries is provided. Planted sludge drying beds are one of these options. It has been piloted in Thailand for four years and details on its performance and operation are presented along with data on the hygienic quality of treated biosolids.
European policy on biodegradable waste: a management perspective
Authors: Gómez Palacios J.M. , Ruiz de Apodaca A. , Rebollo C. , Azcárate J.
Published: May 2018

The main characteristics of the European environmental policy are reviewed. Focusing on EU policy on waste, the paper presents the principles on which EU waste management is founded, particularly the waste hierarchy. In this hierarchy, priority shall be given to prevention of the generation of wastes and of its hazardousness. Secondly, the reuse and the recovery of materials (recycling), which implies the separation of waste at source involving consumers in the scheme of waste management. Priority should be given to material recycling over energy recovery. The less desirable option is the disposal of waste. The paper reviews specific directives on organic waste management, following the scheme of the waste hierarchy, together with the general trends observed in producing common regulations for all types of organic residuals. Afterwards, key issues and measures for the implementation of a feasible strategy for organic residuals management, e.g. quality requirements and quality assurance, are discussed. Finally, there is a view from a manager's perspective on the current EU policy, public acceptance and suitable waste management operations.
Paying for healthy rivers
Authors: Pigram J.J.J.
Published: May 2018

Concerted efforts are being made at state and federal levels to restore Australia's rivers and waterways to a healthy condition. Yet, there is little consensus on what constitutes a ldquo;healthy river” and even less on how to achieve this, or how far to go towards restoration. Some advocate removal of storages and weirs along rivers to revert to some natural state. Others, particularly water users, question the trade-offs involved in leaving more water in the rivers and how the costs of restoration are to be met. At present it seems that the major share of the costs is borne by irrigators, with the wider community essentially enjoying a “free-ride”. This situation is justified on the basis of the impactor pays principle whereby water diversions, primarily for irrigation, are held to have contributed most to degradation of the river systems. The alternative - beneficiary pays principle - is of more relevance where demands are made on resource users to mitigate environmental impacts or bring about environmental improvements, eg. healthy rivers, where the beneficiaries are the wider public and the general community. Many resource users are voluntarily undertaking action on private land to conserve biodiversity and achieve sustainability. In these circumstances, the cost-sharing principle should apply, with governments, interest groups and the community contributing to the investment required to attain the desired resource condition objectives.
The use of rapid environmental assessment techniques to monitor the health of Australian rivers
Authors: Greenwood-Smith S.L.
Published: May 2018

River managers require tools to assess the ecological condition of waterways and prioritise management strategies. As benchmarking the condition of an entire waterway with detailed surveys is often not practical, Rapid Environmental Assessment Techniques have been developed to provide an indication of the state of a river's health, both rapidly and at a low cost. In this investigation, three such techniques, developed recently in Australia, are applied to the same creek in order to compare the outcomes and the levels and types of resources required for their application.

The output from the three indices ranges from descriptive to statistically analysed data, making them difficult to compare directly. Overall, the three indices all report that the sample creek had relatively poor health. The results from the Victorian Index of Stream Condition and New South Wales' Pressure, Biota, Habitat Stream Assessment appear to correlate well.

An important finding of the investigation is the variation in the resources required to apply each assessment technique. Generally, the resource demands increase with the requirement for a higher level of scientific rigour. The methods are either relatively inexpensive and rapid to undertake or more resource intensive, yet thorough in the data collected. A two step process incorporating the techniques in a cost-effective manner is recommended.
Ecological condition of central Australian arid-zone rivers
Authors: Choy S.C. , Thomson C.B. , Marshall J.C.
Published: May 2018

Australian arid-zone rivers are known to be ecologically variable and go through “boom and bust” cycles based on highly variable and unpredictable flow regimes. They are facing increasing pressure from land and water resources development and, whilst they are considered to be still in relatively good condition, no studies have yet been carried out to verify this. Such baseline studies are crucial if we are to assess any ecological changes in response to development and management interventions. The ecological condition of four of these endorheic rivers (Georgina, Diamantina, Cooper-Thomson and Bulloo) flowing into the Lake Eyre and Bulloo Basins in central Australia was assessed using several criteria (level of human influence, habitat condition, water chemistry and aquatic macroinvertebrate composition). Using criteria based on the level of human influence, most of the sites were assessed to be relatively unimpacted (reference) condition. The most discernible and widespread impact was riparian and bank damage by stock access. However, the level of this impact was considered to be only moderate.

Most aquatic macroinvertebrates found in the area are considered to be opportunistic and tolerant of a wide range of environmental conditions, but with their life histories known to be linked to flow conditions. Their trophic guild was dominated by collectors and predators. The AusRivAS modelled observed to expected values of macroinvertebrate composition indicated that there were differences in ecological condition between sites (e.g. different waterholes) and between times (e.g. seasons and years). Overall, 75% of sites were assessed to be good condition with the remainder being mildly impaired.

Water chemistry of the sites was characterised by high spatial and temporal variability with low conductivity and alkaline pH, relatively high turbidity, total nitrogen and total phosphorus, and wide-ranging dissolved oxygen. Given the high variability in water quality and ecological condition within a catchment, there was little evidence of any overall difference in these factors between the catchments. However, given that the hydrology of each river system is distinctly different, one might expect some differences in ecological structure and function at finer scale. Periods of hydrological isolation (eg. to allow natural dryouts) as well as the maintenance of natural connectivity (eg. instream, overbank and floodplain wetting) are both necessary for the maintenance of ecological integrity of these systems.
Present state of food and feed cycle and accompanying issues around Japan
Authors: Ukita M. , Prasertsan P.
Published: May 2018

Nitrogen (N) and phosphorus (P) cycles of food and feed, and the regulation systems for industrial wastewater are studied. The rate of domestic supply of food in Japan is 41% in 1970, 32% in 1990, and 29% in 1998 for N and 33%, 29%, and 28% for P, excluding grass feed. Among 3 countries, Japan, USA and Thailand, Japan is in the most difficult state to recycle food wastes to farmland. Comparing the estimated load of wastewater from food processing industries with the estimated load according to the budget study for N and P cycles, the tentative criteria of wastewater of food processing for P seem to be loose, and de-nitrification might be considered in every stage of N cycles. New regulation of industrial wastewater recently proposed in Japan may induce the chance for environmental business to remove N and P.
Important limitations in the modeling of activated sludge: biased calibration of the hydrolysis process
Authors: Insel G. , Karahan Gül Ö. , Orhon D. , Vanrolleghem P.A. , Henze M.
Published: May 2018

The merit of activated sludge models depends on the accuracy and reliability of the information they contain on the wastewater to be treated and the biochemical mechanisms involved. In most advanced calibration studies, respirometry i.e. the measurement of the oxygen utilization rate, (OUR), provides the majority of the required experimental database. However, currently used procedures still involve a number of basic and practical problems. Model evaluation of the OUR data may generate a distorted image of the processes involved. Hydrolysis is the most important, yet the most vulnerable process as far as the experimental assessment of accurate kinetic parameters is concerned. This study intends to provide an overview of major experimental limitations in the modeling of activated sludge, with emphasis on the appropriate experimental design for the assessment of the hydrolysis rate.
Field test of methane fermentation system for treating swine wastes
Authors: Kataoka N. , Suzuki T. , Ishida K. , Yamada N. , Kurata N. , Katayose M. , Honda K.
Published: May 2018

A methane fermentation system for treating swine wastes was developed and successfully demonstrated in a field test plant (0.5 m3/d). The system was composed of a screw-press dehydrator, a methanogenic digester, a sludge separator, an oxidation ditch (OD) and composting equipment. A performance evaluation was carried out regarding physical pre-treatment using the screw-press dehydrator, methane fermentation for pre-treated slurry, and post-treatment for digested effluent by OD. Total solids (TS) and chemical oxygen demand (CODCr) removal by the screw-press pre-treatment were 38% and 22%, respectively. Properties of the screenings were as follows: water content 57%, ignition loss 93%, specific gravity 0.33. The pretreated strong slurry was digested under mesophilic conditions. Digestion gas (biogas) production rate was 25 m3/m3-slurry (NTP) and methane content of the biogas was 67%. CODCr removal of 65% with methane fermentation treatment of the slurry operating at 35°C was observed. No inhibition of methane fermentation reaction occurred at the NH4+-N concentration of 3,000 mg/l or less during methane fermentation by the system. Mass balance from the present pilot-scale study showed that 1m3 of mixture of excrement and urine of swine waste (TS 90 kg/m3) was biologically converted to 25 m3/m3-slurry (NTP) of biogas (methane content 67%), 100 kg of compost (water content 40%, ignition loss 75%), and 0.80 m3 of treated water (SS 30-70 mg/l).
A strategy in wastewater treatment process for significant reduction of excess sludge production
Authors: Shiota N. , Akashi A. , Hasegawa S.
Published: May 2018

A novel wastewater treatment process (S-TE PROCESS®) with significantly reduced production of excess sludge has been developed. The process consists of two different stages, one for a biological wastewater treatment and the other for a thermophilic aerobic digestion of the resulting sludge. A portion of return sludge from the wastewater treatment step is injected into a thermophilic aerobic sludge digester (TASD), in which the injected sludge is solubilized by the action of thermophilic aerobic bacteria. The solubilized sludge is returned to the aeration tank in the wastewater treatment step for its further degradation. Pilot-scale facilities of the S-TE process and the conventional activated sludge process as a control, both treating the same industrial wastewater, were comparatively operated for totally 270 days. As a result, 93% reduction in overall excess sludge production was achieved in the S-TE operation. The SS solubilization rate in TASD was stable at around 30%. Only a slight increase in the effluent SS and TOC concentrations was observed compared with those of the control facility. Otherwise the removal efficiency of TOC was approximately 95% for both plants. A full-scale plant treating domestic sewage was operated for three years, showing 75% reduction of overall excess sludge production. It was concluded that the new process was feasible.
A hybrid two-phase system for anaerobic digestion of food waste
Authors: Wang J.Y. , Xu H.L. , Tay J.H.
Published: May 2018

A hybrid two-phase system, consisting of a solid waste reactor as the acidification reactor and a wastewater reactor, i.e. an upflow anaerobic sludge blanket (UASB) reactor, as the methanogenic reactor, for anaerobic digestion of food waste was investigated. After the pre-acidification stage, COD and total VFA removals in the methanogenic phase were in the ranges of 74-93% and 77-100%, respectively, while leachate COD and total VFA concentrations in the acidification phase decreased by 95% and 97-99%, respectively. Some 99% of the total CH4 generated was from the methanogenic phase with the CH4 content of 68-70%. About 77-79% of TOC, 57-60% of volatile solids and 79-80% of total COD were removed. The results of this laboratory-scale study show that the hybrid two-phase anaerobic batch reactor system is suitable for effective conversion of food waste into CH4 and CO2. The hybrid two-phase system can be further developed into an effective and efficient way to enhance waste stabilization in operating bioreactor landfills.
Effect of solution parameters on the removal efficiency of humic substances by a reuse material
Authors: Adou A.F.Y. , Muhandiki V.S. , Shimizu Y. , Matsui S.
Published: May 2018

This paper provides an overview of the ability of polypropylene (PPL), a synthetic polymeric adsorbent made from reused plastic material. The removal of humic substances (HS) in a solution pretreated with dedoxyltrimethylammoniumbromide (DDTMAB), a cationic quaternary ammonium compound (QAC), was studied under various conditions. The removal of HS was achieved in its solute complexed form but also as suspended solids. The conditions of the HS solution, which fluctuation was suspected to have an impact on the performance of the adsorbent, were tested. The parameters investigated included the pH, the initial concentration of the surfactant, and the presence of suspended solids in solution. The results of the laboratory scale experiments showed that PPL removal efficiency of HS is strongly pH dependant with higher removal achieved at pH greater than 7. However, the shift for pH above 7 induced an increase in the optimum doses of DDTMAB as more and more deprotonated HS become available to react with DDTMAB. Ionic strength did have the opposite effect: the increase of ionic strength by addition of NaCl decreased PPL removal of HS.
Fouling of reverse osmosis and nanofiltration membranes by diary industry effluents
Authors: Turan M. , Ates A. , Inanc B.
Published: May 2018

Fouling experiments of nanofiltration (NF) and reverse osmosis (RO) are reported for treatment of the effluent of chemical-biological treatment plant and the original effluent of dairy industry respectively. In the experiments, a thin film composite type of spiral wound was used and fitted with flowmeters and pressure sensors. The feed water was stored into a feed tank and passed a fine filter and was pumped to membrane. Brine and permeate were recirculated back to the feed tank. Membrane fouling was investigated with 16 and 30% water recovery of a single membrane at different pressures and flowrates for RO and NF membranes respectively. Fouling is evaluated with a relationship between relative flux (J/Jo) which is the ratio of the flux at any time during the fouling test to the initial flux and relative resistance (Rf/Rm) which is the ratio of fouling (cake) layer resistance to clean membrane resistance. Turbidity, conductivity, chemical oxygen demand (COD), total suspended solids (TSS) and total hardness were measured in the feed and permeate side of each membrane. The effluent total hardness concentrations of chemical-biological treatment plant were found greater than the influents. The results are presented in terms of the relative flux as a function of time related to hydrodynamic conditions and pollution characteristics of wastewater. The permeate water flux of RO membrane decreases more rapidly than NF membrane. the relative flux decreases with increasing the fouling layer resistance, Rf onto membrane surface. 50% the drop of permeate flux was observed for RO and NF membranes after 50 h and 80 h of operation, respectively. The fouling rate increases with an increase in the concentration of the wastewater constituents in the dairy industry. The relative flux decreased 10 and 20% with increasing chemical oxygen demand (COD) from 5,000 mgl−1 to 10,000 mgl−1 and from 45 mgl−1 to 450 mgl−1 for RO and NF membranes, respectively after 45 h of time. Fouling of membranes resulted in 100% increase of specific energy consumption as the relative permeate fluxes of NF and RO membranes decreased 30 and 40% respectively. The average of specific energy consumption was obtained at 6 and 10 kWhm−3; consequently, operational costs were estimated at U.S. $0.45 m−3 and U.S. $0.75 m−3 for NF and RO units respectively. Also, operational cost for chemical-biological treatment was found at U.S. $0.30 m−3.
Water and wastewater minimization plan in food industries
Authors: Ganjidoust H. , Ayati B.
Published: May 2018

Iran is one of the countries located in a dry and semi-dry area. Many provinces like Tehran are facing problems in recent years because of less precipitation. For reduction in wastewater treatment cost and water consumption, many research works have been carried out. One of them concerns food industries group, which consumes a great amount of water in different units. For example, in beverage industries, washing of glass bottles seven times requires large amounts of water but use of plastic bottles can reduce water consumption. Another problem is leakage from pipelines, valves, etc. Their repair plays an important role in the wastage of water. The non-polluted wasted water can be used in washing halls, watering green yards, recycling to the process or reusing in cooling towers. In this paper, after a short review of waste minimization plans in food industries, problems concerning water consuming and wastewater producing units in three Iranian food industries have been investigated. At the end, some suggestions have been given for implementing the water and wastewater minimization plan in the companies.
Filamentous bacterial population dominance in activated sludges subject to stresses
Authors: Gaval G. , Duchène P. , Pernelle J.-J.
Published: May 2018

Evolution of a filamentous bacterial population was monitored on four wastewater treatment pilot plants subject to stresses which have consisted of oxygen deficiencies and/or loading shocks. Fluorescent in situ hybridization (FISH) was used to perform filaments identification and quantification. Results obtained on the different pilot plants have led us to conclude that independently of the nature of the stresses, a single filamentous bacteria species was involved in the increase of the sludge volume index associated to the filamentous growth. In addition, when serial stresses were used, substitutions in dominant filamentous populations occurred: if another filament began to proliferate it caused the regression of the one which dominant.
Biological iron oxidation-reduction and the effects on sulfur oxidation-reduction, denitrification and poly-P accumulation in an anaerobic-oxic activated sludge
Authors: Yamamoto-Ikemoto R. , Komori T. , Matsui S.
Published: May 2018

Iron oxidation and reduction were examined using the activated sludge from a municipal plant. Iron contents of the activated sludge were 1–2%. Iron oxidation rates were correlated with the initial iron concentrations. Iron reducing rates could be described by the Monod equation. The effects of iron reducing bacteria on sulfate reduction, denitrification and poly-P accumulation were examined. Iron reduction suppressed sulfate reduction by competing with hydrogen produced from protein. Denitrification was outcompeted with iron reduction and sulfate reduction. These phenomena could be explained thermodynamically. Poly-P accumulation was also suppressed by denitrification. The activity of iron reduction was relatively high.
Phylogenetic and physiological characterization of a “Nostocoida limicola”-like organism isolated from activated sludge
Authors: Schade M. , Beimfohr C. , Lemmer H.
Published: May 2018

Ten strains of “Nostocoida limicola”-like organisms were isolated from a municipal wastewater treatment plant with minor industrial effluent. The near complete 16S rDNA sequences were determined for four strains to analyze the position of the organisms within the phylogenetic tree. All four isolates showed the same 16S rRNA sequence and cluster within the green non sulfur bacteria. Hybridization with oligonucleotide probe AHW183 designed complementarily to diagnostic regions of the 16S rRNA sequences showed a positive reaction with all isolated strains. Hybridization of activated sludge samples with probe AHW183 indicates the filamentous “Nostocoida limicola”-like bacteria commonly to occur inside the sludge flocs and to hardly be detected within the flocs without a specific staining. On HA-medium all strains grow as long coiled, unbranched and unsheathed filaments which usually stain Gram positive and show a variable Neisser reaction. The isolates grow well in liquid HA-medium at COD values between 1 to 4 g O2 l−1 and a pH range from 6.0–7.8. No growth is detected in liquid R2A-medium and several synthetic mineral salts media containing various carbon and nitrogen sources.
The “Nostocoida limicola” story: resolving the phylogeny of this morphotype responsible for bulking in activated sludge
Authors: Seviour R.J. , Liu J.-R. , Seviour E.M. , McKenzie C.A. , Blackall L.L. , Saint C.P.
Published: May 2018

On the basis of 16S rRNA sequence analyses of several isolates of “Nostocoida limicola” from activated sludge plants in Australia and other countries, it is clear that “N. limicola” I, II and III are not three morphological variants of a single bacterium but at least three phylogenetically different bacteria. Data show that “N. limicola” I are members of at least two genera in the low mol% G+C Gram-positive bacteria, while some isolates of “N.limicola” II belong to the high mol% G+C Gram positive bacteria, and “N.limicola” III is a member of the Planctomycetales. Design and application of 16S rRNA targeted probes for each to biomass samples suggests that their phylogeny is more diverse than pure culture studies would suggest.
An integrated approach to analyse biofilms of a full scale wastewater treatment plant
Authors: Martín-Cereceda M. , Pérez-Uz B. , Serrano S. , Guinea A.
Published: May 2018

A rotating biological contactor (RBC) system operating in a full-scale wastewater treatment plant has been described by several approaches accounting for performance, composition and structure of biofilms in three stages through biological wastewater treatment (RBC1, RBC 2, RBC 3). RBC biofilms were effective in removing the BOD loading from 13 g BOD5 d−1 m−2 in RBC 1 to 6 g BOD5 d−1 m−2 in RBC 3. Analysis of biofilm composition showed: i) the volatile solids were similar in the three RBCs (0.6 g m−2 VS per g m−2 of TS); ii) the protozoan and metazoan biocenosis was mainly made up of ciliated protozoa, which were most abundant in RBC 2 (1.84 × 106 ciliates g−1 VS). Relationship between ciliate species and physical-chemical profile of the system by cluster analysis indicated that the species Acineria uncinata, Amphileptus punctatus, Cinetochilum margaritaceum and Holosticha mancoidea were associated with the best RBC performance; iii) the exopolymeric matrix of the three RBC biofilms was mainly constituted by proteins, although humic substances, polysaccharides, uronic acids and DNA were also found. Analysis of biofilm structure by confocal microscopy indicated changes in biofilm organisation with depth. Results have been brought together and a graphic representation of the composition and architecture of RBC biofilms is presented.
Quantification of functional groups in activated sludge by microautoradiography
Authors: Nielsen J.L. , Nielsen P.H.
Published: May 2018

Different functional groups of bacteria in activated sludge from a Danish municipal wastewater treatment plant were investigated and quantified on the basis of their ability to take up acetate under different electron acceptor conditions. The number of bacteria in the different functional groups was quantified by microautoradiography or by fluorescence in situ hybridization (FISH). Uptake of radiolabeled acetate was tested under conditions where oxygen, nitrate, ferric iron, and sulfate served as electron acceptors and under methanogenic conditions. Ammonia-oxidizing bacteria and nitrite-oxidizing bacteria were enumerated by applying oligonucleotide probes (FISH). 80% of the total DAPI count hybridised with a mixture of bacterial probes. Most baceria were able to take up acetate with oxygen or nitrate as electron acceptors (74 and 71% of all DAPI-stained bacteria, respectively). The very similar numbers indicate that the alternating aerobic and anoxic conditions in the wastewater treatment plant investigated favoured the presence of facultative aerobic and denitrifying heterotrophic bacteria. The number of bacteria able to take up acetate under anaerobic conditions was around 8% of the total DAPI count. About half of these were able to take up acetate and store it and were thus probably phosphate-accumulating organisms. The remaining 4% of anaerobic acetate-consuming bacteria were mainly iron reducers. By incubating the sludge samples with specific inhibitors against sulfate reduction and methanogenic activity, it was found that sulfate reducers and methanogenic bacteria constituted approximately 1% and less than 0.5% of the total DAPI count, respectively.
Genomic fingerprinting of the 16S-23S gene spacer region suggests that novel Acinetobacter isolates are present in activated sludge
Authors: Carr E. , Seviour R.J. , Gürtler V.
Published: May 2018

The taxonomic status of the genus Acinetobacter is currently confused and the role of these organisms in activated sludge is poorly understood. Currently unidentified isolates of Acinetobacter from activated sludge were fingerprinted by making use of polymorphisms in their 16S-23S rDNA spacer region. The PCR amplified 16S-23S rDNA spacer region was digested with five different restriction enzymes to further differentiate between the isolates. The resulting band patterns were very diverse and the data suggests that the activated sludge isolates are different to the known genomic species of Acinetobacter which are predominantly clinical isolates. The results of this study imply the existence of yet unrecognised species of Acinetobacter in activated sludge.
Bulking sludge solved?!
Authors: Kruit J. , Hulsbeek J. , Visser A.
Published: May 2018

At present there is still no final theory explaining the bulking of activated sludge. Previous investigations showed that the sludge settling properties become better and more stable when more plug flow conditions are implemented in wastewater treatment plants for biological nutrient removal. In this research the effect of the process configuration (4 wwtps with fully biological nutrient removal) on the sludge settling properties has been investigated. The results show that a separate anoxic reactor can not avoid the presence of LCFA for the growth of M. parvicella in the anaerobic reactor. A SVI < 120 ml/g could be achieved by: implementation of a separate anoxic reactor with plug flow conditions, introducing of a strictly anaerobic reactor (UCT-modification), implementation of an extra anoxic/aerobic reactor, maintaining a high oxygen concentration (> 1.5 mg/l) and creating a low ammonium concentration (< 1 mg/l) in the aerobic reactor.
Influence of the nutrient balance on biofilm composition in a fixed film process
Authors: Hendrickx T.L.G. , Meskus E. , Keiski R.L.
Published: May 2018

An attached fungal growth has appeared in a fixed biofilm process at the waste water treatment plant of the City of Oulu, Finland. Due to the filamentous morphology of the fungi, biofilm support material is easily washed out. The appearance is believed to be the result of the unbalanced availability of nutrients, where phosphorus has been identified as the key component. Experimental work concentrated on the influence of phosphorus on the fungal growth. Bench scale experiments showed that a higher uptake of phosphorus for the removal of organic material is possible, which also resulted in a suppression of the fungal growth by bacterial biomass. The results were confirmed by experimentation in a full-scale biofilter. Addition of extra phosphoric acid to the biofilter influent resulted in a biofilm where the fungal growth is less pronounced. The fungal growth is believed to be competitive with the desired bacterial growth. It is possible to keep the fungal growth within limits by changing the conditions in favour of the bacterial growth, thus avoiding the operational problems connected with the filamentous fungi.