The Chlorine Institute

There are so many interesting an informative websites in cyberspace now that it is hard to keep track. An interesting one for me is the Chlorine Institute which works with the Chlor-alkali industry. Chlorine is synonymous with water and wastewater disinfection, although it has enormous industrial applications. But those of you interested in the use of chlorine and its derivatives for water disinfection should check out this large and informative site. There is a particularly interesting section on Emergency Response. Link.

Perchlorate In Irish Drinking Water a Potential Cause of Hyperthyroidism?

Attention is increasingly being focused on perchlorate in drinking water as prolonged exposure is known to suppress thyroid function. The sources of perchlorate in Ireland are quite limited but one area that urgently needs investigation is the use of sodium hypochlorite for water treatment. Other potential sources are household bleach and sodium hydroxide.

Sodium hypochlorite is a very common method of disinfecting water especially in smaller drinking water suppliers. The quality, storage and use of these chemicals varies considerably. When used it will dissociate to produce some perchlorate ions. Wherever sodium hypochlorite and sodium hydroxide are used there is a potential for perchlorate release into the environment.

A study carried out by NSF International in the US, and published in the Journal of the American Water Works Association found that perchlorate was found in 90% of sodium hypochlorite used at water treatment plants with the concentration increasing as the sodium hypochlorite aged. Their conclusions were: “For utilities that routinely use their sodium hypochlorite within 45 days of manufacture, the contribution of perchlorate is likely to be negligible, unless there is some contamination of the original ingredients. Utilities or small systems that store sodium hypochlorite for longer periods may encounter significant levels of perchlorate in the finished drinking water. To minimize the perchlorate risk, sodium hypochlorite should be stored in the dark, at cool temperatures, diluted if possible, and used within a few weeks of manufacture. Storage tanks and piping should also be emptied of aged material and flushed to minimize the potential for contamination.” Link

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.

Inspecting Septic Tanks

New regulations coming into place next year will require all septic tank systems in Ireland to be inspected.  Here is a interesting video from the US looking at some problems associated with tank assessment.

Waste Framework Directive: Public Consultation

Ireland is in the process of bringing the EU Waste Framework Directive (2008/98/EC) into Irish law through the provision of new regulations.  The Department of Environment, Heritage and Local Government are now calling for comments and/or submissions on the draft regulations.  These must be forwarded to Gerry Byrne by 26 November, 2010 as Member States must complete the process by 12 December.  To access the draft regulations use this link.

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.