New Research Theme Underway: New paper on Peat Filtration

There are many domestic treatment systems available but little real treatment data on existing systems carried out independently.    So our new research theme asks the question: How good are small-scale biological treatment systems?

Most studies on treatment systems have been done immediately post commissioning leading to over expectations of systems and generally poor performance evaluation which could result in long term environmental problems.

So just how well do these systems work?  The first paper in this series has just been published jointly with John Coady and there are 50 free downloads for the paper which became available online on September 3^rd 2014. Link:http://www.tandfonline.com/eprint/4E8eHpEkAB7T2Wjz4UPW/full

The full reference is:

N.F. Gray and  J. Coady (2014): Evaluation of full-scale vertical peat biofilters for treatment of septic tank effluents, International Journal of Environmental Studies, DOI:  10.1080/00207233.2014.954819

Septic tank charges and community advisory groups

A letter dropped through my letter box yesterday from Wicklow Council inviting me to register my household wastewater treatment system (if I have one) before February 1st, 2013. By last Friday only 2,500 households had registered their septic tanks. This is a huge disappointment to the Irish Government who had hoped that their €5 early registration fee incentive for early, set to end on the 28th of this month when the normal fee of €50 euro will come into force, would see the majority of systems registered. According to the CSO there are 497,281 septic tanks and household treatment units in the country, but this is probably a huge underestimation when holiday homes and more isolated dwellings are taken into account. Rural people are very concerned that the follow up inspections will force them into huge investments, with the added worry of unscrupulous individuals selling unnecessary upgrades and package systems to the unsuspecting owners, especially elderly who are most vulnerable in rural areas. My advice is to get registered now at the reduced rate and save yourself €45 as it is inevitable that all tanks will eventually be traced through ESB connections etc. The best approach to the inspections is to form community advisory groups to follow up on inspection reports and to help locals get the best advice and price on upgrades where necessary

Activated Sludge Foaming - New Publication

PhD student Martin Fryer and Professor Nick Gray of the Water Technology Research Group, based in the Centre for the Environment have published a new and precise method for estimating foam development in full scale aeration tanks in wastewater treatment plants. Foaming is a major problem in the operation of activated sludge treatment which is a biological process that treats 90% of wastewater in the developed world. The new methodology opens up the possibility of better foam prediction allowing more time for operators to prevent problematic foam occurring; as well as now being able to measure the effect of remedial action. The foaming Scum Index (FSI) has been presented in the latest issue of the Journal of Environmental Management.



Fryer, M. and Gray, N.F. (2012) Foaming Scum Index (FSI) – A new tool for the assessment and characterization of biological mediated activated sludge foams. Journal of Environmental Management , 110, 8-19. Doi:10.1016/j.jenvman.2012.05.009

Irish Water will become a subsidiary of Bord Gáis

The Government announced today that the new State water authority Irish Water will become a subsidiary of Bord Gáis (The State owned Irish Gas Company). The formation of a new State Water Authority is to be welcomed as it will for the first time facilitate the provision of water, sewerage and wastewater to be operated holistically. It may also allow Irish Consumers, for the first time, to have the same rights as water consumers in other countries and a proper route for the handling of complaints about water quality, something that is currently lacking in Ireland. On the whole the County Councils and Local Authorities have done an amazing job over the years and to some extent it is sad to see this come to an end. However, the senior management in County Councils didn’t rise to the challenge and have now lost one of their key roles.

In some areas local authorities have failed to react to the real needs of consumers and the poor provision in some areas, often linked with poor planning decisions, has left us with complex supply and sewage treatment problems. However, hidden away in water and wastewater treatment plants around the country we have a wealth of fantastic technical and operational personnel with extensive expertise, which I hope will now be allowed to play a more central role in the operation and management of our water services.

We must be very careful to remember that in all the hype about charges there are real public health issues at the core of this change as well as the environmental issues. Personally I would have preferred to have seen a standalone Water Authority similar to those in the UK prior to privatization based on regional areas where staff, equipment and expertise could be shared. Ireland is small enough to have based these on our existing River Basin Districts and to have had the catchment management functions associated with River Basin Management Plans also come under their auspices. Apart from knowing how to collect revenue and lay pipes, I am at a loss to know what Bord Gáis can bring to this critically important and technically very different industry.

The water industry represents a massive and continuous investment by the tax payer for over a century and it should not be allowed to be asset stripped by the private sector, although it is unlikely that with its small size, dispersed population and the complex arrangement with Group Water Schemes that it will prove to be an attractive investment for some time to come. I wish Water Ireland well, but hope that it creates a sustainable water infrastructure for the future and prosperity of Ireland.

Confusion Reigns Over Septic Tank Registration

County Councils throughout Ireland have been inundated with enquiries relating to how to register their home wastewater treatment systems. The best they have been able to do is to redirect enquiries to the Department of the Environment, Community and Local Government. The situation has become quite confused and much of the good will that was out there appears to be evaporating very quickly. The Government needs to clearly set out a proper timescale and mechanism for registration so that those who have septic tank and home treatment systems know what to do.  

The environ.ie website has some good advice to householders, which will form part of the new standards, that will help them prepare for inspections that are due to begin in 2013:

• Know where your tank is located;
• Visually examine your tank every year;
• Ensure only domestic waste water is treated in your tank;
• Ensure your tank only discharges from those points for which it was designed to discharge from;
• Ensure the effluent is not discharged to or does not rise to the surface of the ground;
• Ensure your tank is not discharging into streams/ditches;
• Desludge your tank when necessary, using an authorised waste collector;
• Ensure that your tank is not polluting and operation and maintenance is in compliance with the manufacturer’s manual, as appropriate.

More information at link.

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.

Decarbonisation at UK Wastewater Utilities

An article by Mark Kowalski and Line Poinel of WRc caught my eye today. It deals with the problem of energy use at UK treatment plants. Seventy five percent of their operational carbon dioxide emissions are coming from the use of electricity via the National Grid. The industry are committed to offsetting 20% of this by 2020 by a greater use of renewables. The article is published in the autumn edition of Water and Sewerage Journal.  Link

Crap in a Bag Could Change the World?

Introducing the Peepoo. This is a novel approach to improving sanitation while at the same time creating useful biomass and fertilizer. The use of night soil has been exploited by farmers for centuries, but the introduction of the Peepoo is a clever idea to prevent disease transmission and to generate income in developing countries.
The Peepoo is a biodegradable plastic bag 14 x 38 cm which people use as a portable toilet. The bag contains urea powder which reacts with the urine and faeces helping decomposition but also raising the pH. Pathogens are inactivated within 2-4 weeks depending on the temperature. The bioplastic is made from a mixture of aromatic co-polyesters and polylactone acid (PLA), with small additives of wax and lime. With time these degrade in the soil to release the N and P as well as adding vital water retaining biomass to the soil. As fertilizer is expensive in developing countries many local suppliers of Peepoo bags pay a small refund if the bag is returned full. These are then stored in heaps and allowed to slowly degrade producing a sellable nutrient enriched biomass for local farmers. One person using the bags for a year is equivalent to an artificial fertilizer loading of 6 kg urea 2 kg Total P and 1 kg potash.

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.

New Wastewater Treatment Plant for North Dublin

Fingal County Council has identified nine possible sites for its new wastewater treatment plant to serve North Dublin County. This will also include a new sewerage network and a marine outfall.   It is holding a number of public consultations days at their offices in Swords.  Further details can be accessed at their website. 

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 .

World Water Week

Each year the Stockholm International Water Institute (SIWI) hosts World Water in Stockholm. Since 2009 the massive event which consists of a large range of seminars, workshops, lectures and visits has been dealing with the issues around Responding to Global Changes. This year the main theme is Water in an Urbanising World. You can be involved by using the extensive official website. Link

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.

Some Thoughts on the E.coli Outbreak in Germany

I suppose the many hundreds of students who have attended my introductory lectures on wastewater treatment can attest to my call for the past thirty years for microbial standards to be placed on wastewater treatment plants, and in particular to focus more closely on pathogen removal during treatment.  Wastewater treatment plants, especially activated sludge reactors, are ideal places for new strains of bacteria and antibiotic resistance to develop.  Our simple barrier approach to pathogen control based largely on dilution of effluents and the disinfection of drinking water has served us well, but the reuse of wastewater effluents, contaminated surface and ground waters are all direct routes to the food chain.  While the source of the current outbreak of E. coli  in Germany remains unknown, we should not rule out the very high possibility of such a link.  The need for better operational management coupled with final effluent disinfection to deal with pathogen release from treatment plants must be put on the agenda for a revised Urban Wastewater Directive, where emphasis is placed equally on both environmental and public health protection. 

Willows for wastewater treatment



On of many infected and dead willows



Infected willow now completely dead

Infected plant showing signs of die back

Healthy plant



There is much interest in the use of willows as part of the treatment sequence for single houses.  I have planted a small stand of the Common Osier Salix viminalis around the base of the percolation area from my septic tank. The objective is to encourage evapotranspiration during summer and to provide a barrier between the treatment area and the boundary of my property.  The stand is now about eight years old and last year many of the trees began to show signs of infection.  This year the infection (fungal) has spread and about a third of the trees have now died. Although I have replanted, I am concerned that this infection will spread. Has anyone else come across this problem?

PhD Scholarship with Water Technology Research Group

Applications are sought from suitably qualified candidates (plant science, experimental biology, environmental science) to work on a 4 year PhD studentship entitled Sustainable nutrient and metal removal from domestic and industrial wastewaters using Lagarosiphon major and other submerged macrophytes under temperate conditions. Application deadline is 13 May 2011 and all applications must be made through: Link The studentship will be based with the Water Technology Research Group based inTrinity College Dublin at the Centre for the Environment.

MSc Students Visit Swords STW

Francis O'Hagan and the MSc
students examining the final effluent

The students of the MSc course in Environmental Science were given VIP treatment when they visited Swords Sewage Treatment Works operated by Fingal County Council.  We were shown around by plant supervisor Mr Francis O’Hagan who gave a very useful insight into the management and operation of a modern wastewater treatment plant. The incredibly low odour at the plant coupled with an excellent final effluent is a huge credit to all the staff of this local authority run plant.

New Publication of Foam Potential Measurement

Accurate measurement of foaming at activated sludge plants can be subject to large variation. In this study foam measurements are reviewed and two approaches to foam potential assessment are compared. The paper, written jointly by Martin Fryer and Eoghan O’Flaherty of the Water Technology Research Group at Trinity College Dublin, is available on open access at Link.

The full reference is: Fryer, M., O’Flaherty, E. and Gray, N.F. (2011) Evaluating the Measurement of Activated Sludge Foam Potential. Water, 3(1), 424-444. doi:10.3390/w3010424. Free download

New PhD studentship

A new four year PhD studentship is available with the Water Technology Research Group from September 1st 2011 funded by the Irish Government under the National Development Plan 2007-2013. The project explores the question Can submerged aquatic macrophytes be used under temperate conditions to provide a low-carbon sustainable treatment solution for a range of conventional and problematic wastewaters? The project will be examining a range of native and invasive species, including Lagarosiphon major. Further details can be found here.