New Paper on Co-treatment of Acid Mine Drainage with Domestic Wastewater

In a new paper published by Theresa Hughes of the Water Technology Research Group the concept of treating acid mine drainage with conventional domestic wastewater using activated sludge has been shown to be a viable option. Using a synthetic drainage toxicity tests showed that activated sludge can withstand high proportions of AMD (EC50 19–52% AMD by volume). Laboratory-based sequencing batch reactors were also used to examine the treatability of AMD. Results from OUR inhibition tests on acclimatized activated sludge indicated that over a relatively short timescale (21 days), the activated sludge microbial community can adapt to AMD sufficiently so that shock loads of metals and acidity do not significantly inhibit OUR.
Theresa A. Hughes and N. F. Gray (2012) Acute and Chronic Toxicity of Acid Mine Drainage to the Activated Sludge Process. Mine Water and Environment, 31, 40–52 (DOI 10.1007/s10230-011-0168-y) Link

New Research Paper from the Water Technology Research Group.

The latest research paper from the Water Technology Research Group

Dubber, D. and Gray, N.F. (2011) The influence of fundamental design parameters on ciliates community structure in Irish activated sludge systems. European Journal of Protistology, 47, 274-286.

Abstract
The protozoan community in eleven activated sludge wastewater treatment plants (WWTPs) in the greater Dublin area has been investigated and correlated with key physio-chemical operational and effluent quality parameters. The plants represented various designs, including conventional and biological nutrient removal (BNR) systems. The aim of the study was to identify differences in ciliate community due to key design parameters including anoxic/anaerobic stages and to identify suitable bioindicator species for performance evaluation. BNR systems supported significantly different protozoan communities compared to conventional systems. Total protozoan abundance was reduced in plants with incorporated anoxic and anaerobic stages, whereas species diversity was either unaffected or increased. Plagiocampa rouxi and Holophrya discolor were tolerant to anoxic/anaerobic conditions and associated with high denitrification. Apart from process design, influent wastewater characteristics affect protozoan community structure. Aspidisca cicada was associated with low dissolved oxygen and low nitrate concentrations, while Trochilia minuta was indicative of good nitrifying conditions and good sludge settleability. Trithigmostoma cucullulus was sensitive to ammonia and phosphate and could be useful as an indicator of high effluent quality. The association rating assessment procedure of Curds and Cockburn failed to predict final effluent biological oxygen demand indicating the method might not be applicable to treatment systems of different designs.

PhD Student Wins Award

Congratulations to PhD Research Student Theresa Hughes of the water Technology Research Group, who won the best student paper award at the 2011 national meeting of the American Society of Mining and Reclamation held at Bismark in the USA for her paper 'Co-treatment of acid mine drainage with municipal wastewater using the activated sludge process: preliminary treatability studies.'  The paper has been published in the conference proceedings: Reclamation: Sciences Leading to Success edited by Professor  R.I. Barnhisel, pages 283-305, published by the ASMR, Lexington .

Successful PhD candidate

Congratulations to our colleague Donata Dubber for successfully defending her PhD thesis ‘The effect of anoxia and anaerobia on protozoan communities in activated sludge operation.’ Dr Dubber has already published a number of research papers on her study including

• Enumeration of protozoan ciliates in activated sludge: Determination of replicate number using probability Water Research 43, 3443-52;
• Replacement of chemical oxygen demand (COD) with total organic carbon (TOC) for monitoring wastewater treatment performance to minimize disposal of toxic analytical waste J. Journal of Environmental Science and Health Part A , 45, 1595-1600;
• The effect of anoxia and anaerobia on ciliate community in biological nutrient removal systems using laboratory-scale sequencing batch reactors (SBRs). Water Research, 45, 2213-26;
• The influence of fundamental design parameters on ciliates community structure in Irish activated sludge systems. European Journal of Protistology, In press.

New Publication on Activated Sludge Protozoa

Donata Dubber, a PhD student with the Water Technology Research Group, has just published a paper on the effect of anoxia and anaerobia on ciliate communities in BNR systems. The key outputs of the study were: (i) aeration conditions play a major role in how protozoan communities develop; (ii) activated sludge ciliates display different tolerances to anoxia/anaerobia; (iii) short times of anoxia enhance protozoan community complexity; (iv) with anaerobic conditions protozoan community complexity and abundances decrease; and finally (v) to ensure optimum performance lengths of anaerobia should be as short as possible.  The research is funded by Science Foundation Ireland.

The full reference is: Dubber, D. and Gray, N.F. (2011) The effect of anoxia and anaerobia on ciliate community in biological nutrient removal systems using laboratory-scale sequencing batch reactors (SBRs). Water Research, 45, (6), 2213-2226.   doi:10.1016/j.watres.2011.01.015

Science Spin March 2011

The March 2011 edition of Science Spin, Ireland's own Science magazine, is now available. Link

Review on Acid Mine Drainage Treatment

Link

Theresa Hughes, a PhD researcher with the Water Technology Research Group  has just published a review on acid mine drainage treatment in the new book Mine Drainage and Related Problems edited by Brock C. Robinson. The full reference is:

Hughes, T.A. and Gray, N.F. (2010) Effectiveness and Sustainability of Active and Passive Systems for the Treatment of Acid Mine Drainage and the Recovery of Metals: A Review, In Mine Drainage and Related Problems (ed. B.C. Robinson) pp. 1-69 Nova Science, New York

Persistent organic pollutants (POPs)

Persistent organic pollutants (POPs) are man-made compounds that can stay in the environment for many years and can accumulate in fatty tissue. The Stockholm Convention in 2005 added nine more compounds to the “dirty dozen”. These POPs include pesticides which are organochlorine compounds such as aldrin, chlordane, DDT, dieldrin, endrin, heptachlor, hexachlorobenzene, mirex, alpha and beta hexachlorocyclohexane (also by-products), chlordecone, and lindane. Industrial chemicals such as PCBs, hexachlorobenzene (also a pesticide), hexabromobiphenyl, hexa- and heptabromodiphenyl ether (commercial octabromodiphenyl ether), pentachlorobenzene, perfluorooctane sulfonic acid and its salts perfluorooctane sulfonyl fluoride, tetra- and pentabromodiphenyl ether (commercial pentabromodiphenyl ether), and unintentional by- products compounds: polychlorinated dioxins and furans. These highly toxic substances are released into the environment though several human activities and travel long distances via air and water. The total distribution of POPs concentrations in water around the world is unknown. For that reason, Dr. Lorena M Rios of the Department of Natural Sciences, University of Wisconsin-Superior, is guest editing a special edition of the on-line journal Water and has issued a call for papers where you can share your research results of these POPs in water and related research in order to make available information about their global environment transport. Closing date 30th April, 2011.

Drinking Water and Health: A Collection of New Research Papers

A wide range of exciting research papers have been published in Dinking Water and Health a special edition of the on-line International Journal of Environmental Research and Public Health  edited by Professor N.F. Gray from Trinity College Dublin. Leading researchers from around the world have contributed papers.

Reviews:
• New Perspectives in Monitoring Drinking Water Microbial Quality Mª José Figueras and Juan J. Borrego

• Human Health Risk Assessment of Pharmaceuticals in Water: Issues and Challenges Ahead Arun Kumar, Biao Chang and Irene Xagoraraki

• Inadequately Treated Wastewater as a Source of Human Enteric Viruses in the Environment Anthony I. Okoh, Thulani Sibanda and Siyabulela S. Gusha

• Water Microbiology. Bacterial Pathogens and Water  João P. S. Cabral

Original Research Papers:
• An Assessment of the Interindividual Variability of Internal Dosimetry during Multi-Route Exposure to Drinking Water Contaminants  Mathieu Valcke and Kannan Krishnan

• Determinants of Use of Household-level Water Chlorination Products in Rural Kenya, 2003–2005 Amy E. DuBois, John A. Crump, Bruce H. Keswick, Laurence Slutsker, Robert E. Quick, John M. Vulule and Stephen P. Luby

• Determinants of Arsenicosis Patients’ Perception and Social Implications of Arsenic Poisoning through Groundwater in Bangladesh M. Mizanur Rahman Sarker

• Different Length (DL) qPCR for Quantification of Cell Killing by UV-induced DNA Damage Knut Rudi, Irina Hagen, Bente Carina Johnsrud, Guro Skjefstad and Ingun Tryland

• Factors Associated to Endemic Dental Fluorosis in Brazilian Rural Communities Efigênia F. Ferreira, Andréa Maria D. Vargas, Lia S. Castilho, Leila Nunes M. Velásquez, Lucia M. Fantinel and Mauro Henrique N. G. Abreu

• Incidence and Distribution of Microfungi in a Treated Municipal Water Supply System in Sub-Tropical Australia Noel B. Sammon, Keith M. Harrower, Larelle D. Fabbro and Rob H. Reed

Metal Variability in Sewage Sludge (Biosolids) to Agriculture Land

Sewage sludge (biosolids) disposed to agricultural land in Ireland need only be analysed once a year if disposed to agricultural land for plants of <100,000 PE according to the Code of Good Practice For the Use of Biosolids in Agriculture published by the Department of the Environment and Local Government in 2008. Metals in Irish sludges have decreased over the past 20 years resulting in their widespread use in agriculture with 76% of the 60,000 t DS produced each year now going to farmland. In a recent study done by Elizabeth Whitney of the Water Technology Research Group, the variability of sludge metal concentrations from 12 wastewater treatments plants was examined every two weeks for up to six months. The sludges showed wide variability as measured by the coefficient of variation (CV) over time with each plant with at least one metal where the CV was >50% over that period. Mean plant CV (and range) of the metals studied were Cr 29.5% (11-91%), Cd 48.0% (3-118%), Cu 73.4% (4-168%), Pb 26.5% (6-115%), Ni 46.5% (6-267%) and Zn 26.7% (6-100%). High CV values were generally indicative of an increasing or decreasing trend. However, on some occasions periods of high metal concentration were recorded indicating an intermittent source. The results show that significant variation in sludge metal concentrations occur over time and that in order to ensure safe disposal to agricultural land, the required certificates issued to farmers containing details of metals in the sludge should be either the actual metal concentrations in sludge applied or at least the upper (90 percentile) limit values based on recent monthly samples in order that correct and safe loading rates can be calculated.

Replacing COD with TOC

A new study published by Donata Dubber of the Water Technology Research Group.

Chemical oxygen demand (COD) is widely used for wastewater monitoring, design, modelling and plant operational analysis. However this method results in the production of hazardous wastes including mercury and hexavalent chromium. The study examined the replacement of COD with total organic carbon (TOC) for general performance monitoring by comparing their relationship with influent and effluent samples from 11 wastewater treatment plants. Biochemical oxygen demand (BOD5) was also included in the comparison as a control. The results show significant linear relationships between TOC, COD and BOD5 in settled (influent) domestic and municipal wastewaters, but only between COD and TOC in treated effluents. The study concludes that TOC can be reliably used for the generic replacement of both COD (COD = 49.2 + 3.00*TOC) and BOD5 (BOD5 = 23.7 + 1.68*TOC) in influent wastewaters but only for COD (COD = 7.25 + 2.99*TOC) in final effluents.

Dubber, D. and Gray, N.F. (2010) Replacement of chemical oxygen demand (COD) with total organic carbon (TOC) for monitoring wastewater treatment performance to minimize disposal of toxic analytical waste. J. Environ. Sci. Health, Part A, 45, (12), 1595-1600.

Group water schemes reviewed

One in five Irish households is not connected to public mains with over 5,500 group water schemes serving 10% of the population.  In her review, just published in the journal European Water, Jennifer Brady examines the structure, the merits and potential disadvantages of the group water scheme model and looks to its future within the Irish water supply industry. Online paper link.  To find out more about Jennifer's research click here.

New book launched

The latest edition of the textbook Water Technology: An introduction for Environmental Scientists and Engineers (740pp) written by Professor Nick Gray of the Centre for the Environment  has been released today. Co-published by Butterworth-Heinemann and IWA Publishing the new third edition has been extensively updated and expanded, and is supported by a dedicated website and blog: http://www.irelandswater.com/. The book is also available on-line.