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 Awarded to Water Technology Research Group Member

Congratulations to former Water Technology Research Group research student Donata Dubber who was awarded her PhD degree today.  The title of her thesis was  The effects of anoxia and anaerobia on protozoan communities in activated sludge operation. The study was supported by Science Foundation Ireland.

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.

Environ 2011

UCC main quadrangle
Copyright UCC

The 21st Irish Environmental Researchers’ Colloquium is being held in University College Cork (UCC) from Wednesday, April 6th to Friday April 8th, 2011. With over 300 researchers and delegates from a wide variety of scientific and engineering disciplines in attendance, this is Ireland’s largest annual environmental event. Postgraduate researchers from throughout Ireland share their research offering a unique opportunity to experience the latest ideas in environmental science and technology. Most of the researchers from the Water Technology Research Group will be in attendance at this year’s colloquium. List of presentations

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

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.