bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enhanced anaerobic degradation of mechanically disintegrated sludge
Authors: Baier Urs , Schmidheiny Peter 
Published: May 2018

Mechanical disintegration - wet milling - was chosen to physically disrupt cellular material. By breaking up microbial or plant cell walls intracellular carbon sources as well as nutrients are made available for further anaerobic digestion. Ball milling consistently showed better disintegration results than high speed cutter milling. With respect to solubilisation of COD a high degree of cell disruption could be achieved in a variety of aerobic and anaerobic sewage sludges, where the fraction of soluble COD could be changed from 1–5% in original sludges to up to 47% after wet milling. In distillery slops and brewery residues milling failed to enhance soluble COD significantly.
Anaerobic digestion testing showed a good digestability of the solubilized intracellular material and consistently enhanced overall COD-degradation of the sludges by a factor of 1.2–1.5. Net biogas production was enhanced in the same order of magnitude. Stabilised sludges showed a higher beneficial effect of wet milling than raw excess sludge.
Enhancement of sludge anaerobic digestion by using of a special thickening centrifuge
Authors: Dohányos Michal , Zábranská Jana , Jenícek Pavel 
Published: May 2018

The intensification method of anaerobic methane fermentation of sludges, based on the stimulation activity of cell lysate, was studied. The effect of lysate is caused by the still remaining activity of released enzymes and by the stimulating properties of other compounds that are present inside the cells. The use of cell lysate as a stimulating agent was examined in the laboratory experiments of anaerobic degradation of municipal raw sludge, excess activated sludge and a mixture of them. The cell lysate was prepared by a partial mechanical destruction of cells of the excess activated sludge by a special adapted thickening centrifuge.
The presence of aerobic cell lysate in thickened excess activated sludge causes a substantial increment in the methane yield and the biodegradability of thickened activated sludge in comparison with untreated excess sludge. The improvement of methane yield and biodegradability is influenced by the quality of input excess activated sludge and the parameters and efficiency of the thickening centrifuge. The improvement of methane yield from thickened activated sludge ranged from 8.1 to 86.4% dependent on the sludge quality. The improvement of methane yield from the mixture of thickened activated sludge and primary sludge ranged from 0 to 24%, and it was predominantly dependent on the fluctuating quality of primary sludge.
The advantages of the stimulation method with the cell lysate are the following: the improvement of the anaerobic biodegradability of organic materials treated, the acceleration of the degradation process, the increment of methane production, the lowering of digested sludge amount and the improvement of the energetic balance of the process.
Aerobic composting and anaerobic digestion of pulp and paper mill sludges
Authors: Jokela Jari , Rintala Jukka , Oikari Aimo , Reinikainen Olli , Mutka Kari , Nyrönen Timo 
Published: May 2018

The feasibility of aerobic vessel composting and anaerobic digestion for the treatment of pulp and paper mill sludges were studied. The composting studies made use of primary and secondary sludge from a de-inking and paper mill. In six parallely aerated 500 1 vessels with various carbon : nitrogen (C:N) -ratios, the most optimal performance was obtained with C:N -ratios of c. 22–35, while higher and lower ratios delayed the temperature increase. With the optimal ratios, the thermophilic stage was reached within 36 h, and the stage lasted for about seven days. In the scale-up study (18 m3 compost vessel), the thermophilic stage was reached within 24 h. An effective dehydratation of the mass was obtained as the total solids (TS) content of the compost increased from 31.3– to 63.8– within 21 days.
The anaerobic digestion of pulp and paper mill sludges was studied using two mesophilic 5 1 digesters, their feed sludges consisting of a mixture of municipal sewage sludge and primary and secondary sludge from a pulp and paper mill. With this feed mixture and with a loading rate of about 1.0 kg volatile solids (VS)/m3d a removal of about 27 to 40– VS and methane production of about 180 1/kgVSadded feed sludge were achieved during the 80 d study period.
The study showed that pulp and paper mill sludges are amenable to both aerobic composting and anaerobic digestion.
Reduction of fecal streptococcus and salmonella by selected treatment methods for sludge and organic waste
Authors: Jepsen Svend-Erik , Krause Michael , Grüttner Henrik 
Published: May 2018

The increasing utilization of waste water sludge and source-separated organic household waste in agriculture has brought the quality aspects into focus, among others the hygienic aspects. In this study, the reducting effect on Fecal Streptococcus (FS) and Salmonella of different methods for stabilization and methods for further treatment of sludge and organic waste has been investigated. The most common methods for stabilization, i.e. aerobic and anaerobic stabilization, only reduce the indicator organisms by approximately 1 logarithmic decade. Methods for further treatment of sludge and organic waste have shown reductions of microorganisms allowing for unrestricted utilization in agriculture, meeting the product control: FS below 100/g and no Salmonella detected.
The effect of storage of sludge at summer and winter temperature respectively has been investigated. At temperatures (around 20°C) significant reductions of Salmonella were found, while the die out at low temperatures (below 10°C) was limited. FS was not reduced systematically during storage, and therefore, FS is not usable as indicator organism for the hygienic properties of sludge during storage.
Application of air backflushing technique in membrane bioreactor
Authors: Visvanathan C. , Yang Byung-Soo , Muttamara S. , Maythanukhraw R. 
Published: May 2018

The optimum air backflushing and filtration cycle was investigated for a 0.1 μm hollow fiber membrane module immersed in an activated sludge aeration tank. It was found that 15 minutes filtration and 15 minutes air backflushing gave the best result both in terms of flux stability and net cumulative permeate volume. Although this cyclic operation could not completely remove the clogging, this process improved the flux by up to 371% compared to the continuous operation.
During the long term runs, three different hydraulic retention times (HRT) of 12, 6 and 3 hours, corresponding to 0.16, 0.32 and 0.64 m3/m2.d of permeate flux respectively, were investigated. Stable operation was obtained at the HRT of 12 hours. Decrease in HRT led to rapid formation of a compact cake layer on the membrane surface thus increasing the transmembrane pressure. It was also noted that filtration pressure increases with increase in bioreactor MLSS concentration. With operation time, the MLVSS/MLSS value decreased without significant effect on the process performance, indicating that inorganic mass constantly accumulated in the bioreactor. All the experimental runs produced more than 90% removal of COD, and TKN. In terms of physical, chemical, biological and bacteriological parameters, the membrane bioreactor effluent was superior to the conventional activated sludge process.
Biological nitrification of kraft wastewater
Authors: Bryant Curtis W. , Barkley W. A. , Garrett Michael R. , Gardner David F. 
Published: May 2018

A program of batch, continuous-flow, and field pilot tests have been conducted to measure the extent and stability of nitrification in kraft wastewater. Laboratory batch tests measured the extent and rate of ammonia removal from kraft wastewater. Controlled variables included aerated stabilization basin (ASB) location, temperature, pH, ammonia concentration, black liquor content, bicarbonate content, and presence of acclimated nitrifying bacteria. Findings were that (a) moderate wastewater temperature (22-35°C), pH near 7.3, and black liquor spill control prevented slowing of nitrification, and (b) provision of acclimated nitrifying bacteria (by appropriate recirculation methods) dramatically reduced the residence time needed for nitrification in kraft ASBs. Laboratory-scale, fixed-film, continuous-flow tests were used to investigate dynamic responses to changes in wastewater composition and flow. Results demonstrated that the nitrifying films were not ‘damaged’ by 4- or 24-hour step increases in influent ammonia, but the films could not respond quickly enough to substantially dampen out the effect on effluent quality.
A pilot 4-stage rotating biological contactor (RBC) was installed at an ASB to test the nitrification of kraft wastewater under actual process variations. The results during the 11-month run were: (a) the RBC demonstrated capability to consistently and substantially reduce NH4-N concentration below 1 mg/L, (b) about one month was needed to establish effective treatment, and (c) effective treatment was sustained at a maximum hydraulic loading rate of 0.11 m3/day per m2.
Laboratory studies on the temperature-phased ASBR system
Authors: Welper Lana L. , Sung Shihwu , Dague Richard R. 
Published: May 2018

Treatment of high-strength industrial wastewater with the temperature-phased anaerobic sequencing batch reactor (ASBR) system has shown positive results in laboratory scale studies. The system achieved COD removals as high as 95% and 90% for soluble and total COD, respectively, up to COD loadings of 22 g COD/L/day. Non-fat dry milk was used as a synthetic substrate.
The system consisted of two reactors operated in series at different temperatures. Phase I of the system was operated at 55°C and the Phase II was operated at 35°C. The total hydraulic retention time in the system was 18 hours (6 hours in the Phase I and 12 hours in the Phase II). The temperature-phased system incorporates advantages of both thermophilic treatment (high reaction rates) and mesophilic treatment (higher quality effluent) while minimizing the disadvantages such as odors commonly associated with thermophilic treatment and lower treatment rates of mesophilic treatment.
This study was conducted using ASBRs. The ASBR was developed at Iowa State University by R.R. Dague. This process allows biomass to increase in the reactors and provides an environment for granulation to occur. Although the ASBR was used for these studies, the temperature-phased process is applicable to other anaerobic treatment processes as well.
Treatment of raw sewage in a temperate climate using a UASB reactor and the hanging sponge cubes process
Authors: Agrawal Lalit K. , Ohashi Yasuhiro , Mochida Etsuo , Okui Hiroyuki , Ueki Yasuko , Harada Hideki , Ohashi Akiyoshi 
Published: May 2018

The treatability of raw sewage in a temperate climate (wintertime around 10–20°C) using an upflow anaerobic sludge blanket (UASB) reactor and the hanging sponge cubes process was evaluated. After being seeded with digested sewage sludge, a 47.1 L UASB reactor was continuously operated for more than 2 years by feeding raw sewage, which had average COD around 300 mg/L (41% soluble). During summertime at an HRT of 7 h, effluent COD approximately 70 mg/L total, 50 mg/L soluble and BOD5 20 mg/L total, 12 mg/L soluble was obtained. During wintertime also, treatment efficiency and process stability was good.
With the hanging sponge cubes process using the effluent of the UASB reactor treating raw sewage, the following results were obtained. The ammonia oxidation rates of 1.9 and 3.5 g NH4-N·m−2·d−1 in a downflow hanging sponge cubes biofilter, under natural air intake only were obtained during wintertime and summertime, respectively. With post-denitrification and an external carbon source, 84% in average N (NO3+NO2) was removed with an HRT of less than 1 hour and in the temperature range of 13 to 30°C using an upflow submerged hanging sponge bed bioreactor, under anaerobic conditions. The overall system using a UASB reactor and the hanging sponge cubes process could be quite an attractive treatment alternative.
Storm water quality modelling, an ambitious objective?
Authors: Ahyerre M. , Chebbo G. , Tassin B. , Gaume E. 
Published: May 2018

As a consequence of the awareness of the pollution impact of storm sewer overflows, managers need tools to evaluate and control stormwaters according to water quality criteria. After an experience of 25 years in storm water quality modelling, very few models are widely and regularly used. According to managers this is due to their cost and their low level of accuracy.
The generation and the transport of the pollution in urban systems during a storm event are very complex because they concern many media and many space and time scales. Nevertheless, a typology of the existing models shows that this complexity has been inscribed into the models. This tendency towards complexity makes sewer quality models difficult to put into operation and three main difficulties can be underlined: doubtful mathematical formulation of processes, uncertainties on input and calibration data, difficulties and cost of calibration.
Further research is needed to improve the modelling approach and basic knowledge, and we think that a clear distinction should be made between management tools and research models.
Landfill codisposal of pentachlorophenol (PCP)-treated waste wood with municipal solid waste
Authors: Pohland F. G. , Karadagli F. , Kim J. C. , Battaglia F. P. 
Published: May 2018

Pentachlorophenol (PCP) has been used as a biocide and preservative for wood power poles and crossarms. If disposed in landfills, the natural capacity of landfills to transform hazardous constituents to less hazardous or inert substances may also apply to such PCP-treated materials. The principal reaction of interest in the anaerobic environment of a landfill is reductive dechlorination.
The fate and transformation of PCP-treated wood was investigated in simulated landfill bioreactors operated under single pass leaching and leachate recirculation. The wood samples consisted of 2% of the total mass by weight loaded into the bioreactors. The PCP leaching potential was examined at varying pH conditions with TCLP and Soxhlet extractions. Adsorption of PCP to the synthetic solid waste was used to determine its role in immobilizing leachate PCP. Routine indicator parameters were used to describe the acidogenic and methanogenic phases of landfill stabilization. Leached PCP was transformed without inhibitory effects on landfill stabilization, thereby affirming the acceptability of such a codisposal practice.
Enhancement of hydroxyl radical generation by phenols and their reaction intermediates during ozonation
Authors: Utsumi Hideo , Han Sang-Kuk , Ichikawa Kazuhiro 
Published: May 2018

Generation of hydroxyl radicals, one of the major active species in ozonation of water was directly observed with a spin-trapping/electron spin resonance (ESR) technique using 5,5-dimethyl-1-pyrrolineN-oxide (DMPO) as a spin-trapping reagent. Hydroxyl radical were trapped with DMPO as a stable radical, DMPO-OH. Eighty μM of ozone produced 1.08 X 10-6M of DMPO-OH, indicating that 1.4% of •OH is trapped with DMPO. Generation rate of DMPO-OH was determined by ESR/stopped-flow measurement. Phenol derivatives increased the amount and generation rate of DMPO-OH, indicating that phenol derivatives enhance •OH generation during ozonation of water.
Ozonation of 2,3-, 2,5-, 2,6-dichlorophenol gave an ESR spectra of triplet lines whose peak height ratio were 1:2:1. ESR parameters of the triplet lines agreed with those of the corresponding dichloro-psemiquinone radical. Ozonation of 2,4,5- and 2,4,6-trichlorophenol gave the same spectra as those of 2,5- and 2,6-dichlorophenol, respectively, indicating that a chlorine group in p-position is substituted with a hydroxy group during ozonation. Amounts of the radical increased in an ozone-concentration dependent manner and were inhibited by addition of hydroxyl radical scavengers. These results suggest that p-semiquinone radicals are generated from the chlorophenols by hydroxyl radicals during ozonation. The p-semiquinone radicals were at least partly responsible for enhancements of DMPO-OH generation.
Pesticides - friend or foe?
Authors: Richardson Mervyn 
Published: May 2018

Pesticides, where used correctly, can save up to 40% in crop losses; however, when pesticides are mal-, mis-or over-used the environmental and public health consequences can be very considerable. The United Nations has issued a list of chemicals that are banned or severely restricted in use; many of the chemicals on this list are pesticides. Whilst the use of highly persistent pesticides such as DDT has proved very effective in the eradication of diseases such as malaria, the adverse effects to the natural environment have been devastating - whole populations of birds have been eliminated.
Within the former Soviet Union, the use of highly persistent pesticides was widespread; this has resulted in contamination of both crops, with pesticide residues well in excess of internationally acceptable maximum residue limits, and water resources to such high level that remediation through natural processes will take decades, or by xenobiotic or physicochemical processes will be extremely costly. This is an extraordinary situation as the former Soviet Union had one of the most stringent of environmental regulation - the GOST regulations; unfortunately these were not pragmatic and rarely applied. When in the Ukraine in 1994, I heard that farmers where paid for every application made; the result was crops, soil, water and the environment were highly contaminated, and in some cases the land became barren. Currently, the situation in some countries is that no pesticides are being applied because under the new market conditions farmers cannot afford to purchase pesticides. In Armenia in July 1995, one could not purchase fruit which was not diseased.
The effects of mis-use of pesticides are known to cause very serious adverse effects to human health: in some countries children are exhibiting excessive cancer incidences; crops found to be highly contaminated with up to five different pesticides are being condemned, often being burnt in the fields. As these crops in all probability contained now banned and highly persistent pesticides, mere burning at low temperatures is producing even more toxic dioxins, furans, etc. This leads to both air and soil contamination. One answer would be for the farmer to be obliged to pay for high-temperature incineration in a high-tech incinerator in a developed country, which, subject to prior informed consent, could cost US $5000/tonne.
However, the application of modern pesticides in accordance with manufacturers' specifications can incur none of these problems; this presentation will outline how pesticides can be used judiciously.
A systematic approach to optimal upgrading of water and waste water treatment plants
Authors: Rosén Björn , Morling Stig 
Published: May 2018

Most of the future works in water and waste water treatment systems will involve the upgrading of existing facilities, for better performance and/or higher capacity. For the efficient implementation of any project, an upgrading strategy should be used, based on careful studies of the local conditions and the defined objectives to be reached.
The paper presents a systematic approach to upgrading with emphasis on treatment plant extension, without investing in large volumes, by more efficient use of existing facilities, illustrated by some cases. The importance of real competition in obtaining a cost-effective implementation is stressed.
Assessing management options for wastewater treatment works in the context of life cycle assessment
Authors: Dennison F. J. , Azapagic A. , Clift R. , Colbourne J. S. 
Published: May 2018

This paper presents the preliminary results of a Life Cycle Assessment (LCA) study comparing different wastewater treatment works, operated by Thames Water Utilities Ltd. in the UK. Fifteen works have been studied, representing a range of size and type of treatment works. Five management regimes for centralising sludge treatment and disposal were analyzed in the context of LCA to provide guidance on choosing the best practicable environmental option (BPEO).
Consideration of Global warming potential indicates that the four proposed management regimes with centralisation of sludge for treatment and disposal, as adopted by Thames Water Utilities Ltd., is an environmental improvement upon the current practice. One of these options, that of complete centralisation and composting of sludge prior to disposal, exerts the least environmental impact with respect to Global warming potential. This suggests that the adoption of composting at Crawley is environmentally preferable to increasing the digestion facility at this works.
Effect of controlled drainage and tillage on soil structure and tile drainage nitrate loss at the field scale
Authors: Tan C. S. , Drury C. F. , Soultani M. , van Wesenbeeck I. J. , Ng H. Y. F. , Gaynor J. D. , Welacky T. W. 
Published: May 2018

Conservation tillage has become an attractive form of agricultural management practices for corn and soybean production on heavy textured soil in southern Ontario because of the potential for improving soil quality. A controlled drainage system combined with conservation tillage practices has also been reported to improve water quality. In Southwestern Ontario, field scale on farm demonstration sites were established in a paired watershed (no-tillage vs. conventional tillage) on clay loam soil to study the effect of tillage system on soil structure and water quality. The sites included controlled drainage and free drainage systems to monitor their effect on nitrate loss in the tile drainage water.
Soil structure, organic matter content and water storage in the soil profile were improved with no-tillage (NT) compared to conventional tillage (CT). No-tillage also increased earthworm populations. No-tillage was found to have higher tile drainage volume and nitrate loss which were attributed to an increase in soil macropores from earthworm activity. The controlled drainage system (CD) reduced nitrate loss in tile drainage water by 14% on CT site and 25.5% on NT site compared to the corresponding free drainage system (DR) from May, 1995 to April 30, 1997. No-tillage farming practices are definitely enhanced by using a controlled drainage system for preventing excessive nitrate leaching through tile drainage. Average soybean yields for CT site were about 12 to 14% greater than the NT site in 1995 and 1996. However, drainage systems had very little effect on soybean yields in 1995 and 1996 due to extremely dry growing seasons.