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. 

Dangerous gases from Septic Tanks

A number of people have emailed me concerning fumes from septic tanks.  The problem with all stored organic wastewaters that go anaerobic is that large quantities of hydrogen sulphide and methane will be produced.  These gases are much heavier than air and displace the air within the tank, so once opened, the gas will rise from the tank and form a dense layer around the manhole at ground level. Hydrogen sulphide is very dangerous and as I said earlier odourless at high (lethal) concentrations so there is always a potential problem.  The key thing here is to ensure that all septic tanks are cross vented.   Cesspools or sealed septic tanks are highly dangerous in this regard.  The most dangerous scenario is where the tank is in a hollow or the entrance is contained in a riser or in a building so that the gas can build up. Never climb into a tank which has only been partially emptied unless you are sure it has been vented with air.  Most complete treatment systems such as the Biocycle are continuously vented via the aeration system, so that such gases should not build up.  However, if you are working in this area, and some of you who emailed me are, you should always have a gas detector.  It is worth the investment.  For more information see Link and more safety information see Link.

Fumes from stored sewage claims life

The sad new that one man has died and a second has been taken to hospital when they were overcome by fumes while emptying a commercial septic tank in East Cork has reminded us all of the dangers of working with stored sewage.  Always be aware of the danger of fumes when working alongside or inside tanks and chambers, over open manholes and in all enclosed spaces where sewage, sludge or slurry is present. Please remember always to be vigilant and carry a gas detector unit with you. Hydrogen sulphide can render you unconscious in seconds and is undetectable at lethal concentrations.

Weil’s Disease (Leptospirosis)

Olympic rowing champion Andy Holmes died last week after contracting Weil’s disease (leptospirosis).  This tragic news highlights the risk to all those working with water and sewage, and of course those who use inland water for recreation, from this waterborne bacterial disease.  Globally up to 10 million people contract the disease each year, although the number of reported cases of the disease in the British Isles is around 100-150 people annually, with farmers, sewage workers, freshwater ecologists and water sport participants (i.e. canoeists, wind surfers and rowers) all in the high risk category.  Advice on safe working practices for those engaged in freshwater monitoring and research can be found in sections 9.2.3 and 13.6 in Water Technology.  The primary infection route for leptospirosis is through damaged skin. So no matter how minor the damage may be (e.g. scratches, rashes etc.) ensure that the area is covered by an effective waterproof barrier if there is a possibility that the skin will come into contact with water potentially contaminated with rat urine (i.e. almost all surface waters). For more information Link.

US Water Infrastructure to be Upgraded

US EPA has announced a new national policy to deal with its aging water infrastructure.  The policy intends to upgrade systems using a range of sustainable options that will be able to deal with the potential storm water issues caused by climate change as well replacing aging systems. Link New York alone has  12,000 km of sewer most now fairly old and either overloaded or in need of replacement. Recently a plan was unveiled to spent $1.5 billion on upgrading their sewerage system to reduce CSOs dumping in excess of 110 billion litres of contaminated water each year into New York surface waters. This upgrade will include a range of sustainable urban drainage options from  green roofs to porous pavements to reduce the volume of surface water going to sewer.