Selectech
Page 1 of 4
[WEBLINK]
September 2014 Newsletter
Take a Look at the latest image
of the Antarctic Ozone Hole
Positive Indications from the
UN Environment Programme
and the World
Meteorological Society
Report by ScienceDaily
Thanks to concerted international
efforts, our ozone layer is well on
track to recovery. This does not
mean that challenges do not remain
ahead, but it is good news!
Without the Montreal Protocol and
associated agreements, atmospheric
levels of ozone depleting substances
could have increased tenfold by
2050. According to global models,
the Protocol will have prevented 2
million cases of skin cancer annually
by 2030, averted damage to human
eyes and immune systems, and
protected wildlife and agriculture,
according to UNEP.
The phase-out of ozone depleting
substances has had a positive spinoff for the global climate because
many of these substances are also
potent greenhouse gases.
The images above show the Antarctic ozone hole on September 16 (the International
Day for the Preservation of the Ozone Layer) in the years 1979, 1987, 2006, and 2011.
The first two maps are based on data from the Total Ozone Mapping Spectrometer
(TOMS) on the Nimbus-7 satellite. The other two maps are made with data from the
Ozone Monitoring Instrument on the Aura satellite. Though taken by different
instruments, the data sets have all been cross-calibrated and reanalyzed by scientific
models.
Credit: Images from NASA animation by Robert Simmon, using imagery from the
Ozone Hole Watch
"On September 23, the UN
Secretary General will host Heads of
State in New York in an effort to
catalyse global action on climate.
The Montreal Protocol community,
with its tangible achievements, is in
a position to provide strong evidence
that global cooperation and
concerted action are the key
ingredients to secure the protection
of our global commons," said Achim
Steiner of the UNEP.
View detail at ScienceDaily
Optimise your Chlorification Process
Monochloramine as a Secondary Disinfectant
Selectech
Page 2 of 4
Monochloramine has been used as a water disinfectant since the 1900's and is popular as a secondary
disinfectant in water, rather than the only disinfectant. Monochloramine takes longer to disinfect water
than does chlorine, so it is seldom used as a primary disinfectant. It's also much less efficient at
deactivating pathogens. The stability of monochloramine is what makes it a useful addition.
According the the EPA, monochloramine use has expanded recently because of new drinking water
regulations that have been developed to limit the amount of disinfection byproducts.
What is monochloramine?
Monochloramine is formed when chlorine, and then ammonia, is added to water, in sequence. In
ammonia, a hydrogen atom is substituted by a chlorine atom to form NH2Cl.
It is a less effective disinfectant than chlorine, but is more stable. Monochloramine lasts longer in water
systems than chlorine.
Advantages:
z
Mainly used as a second disinfectant in water to provide a longer lasting residual level of disinfectant
z Produces fewer potentially harmful disinfection byproducts than Chlorine
z Lower decomposition rate makes it useful in killing longer lasting biofilms in pipes, bacteria and the
organisms that cause Legionnaire's Disease
z Less tendency to react with organics in the water and form taste and odour causing compounds
Just like chlorine, high levels of monochloramine in water can be toxic. Levels are strictly regulated by
local governing bodies.
Free ammonia and monochloramine can both be tested with the Lovibond® MD100 Photometer.
Criteria in South Africa:
Monochloramine in Drinking water:
≤ 3 mg / litre
* SANS 241-1: 2011 Drinking Water Standards
Why test for Ammonia?
Ammonia is highly soluble in water. One volume of water will dissolve 1 300 volumes of NH3. Ammonia
reacts with water to form a weak alkaline.
Most Ammonia in the environment comes from fertilizers (sometimes in the form of Ammonium salts such
as Sulfate and Nitrate. Large amounts are used in the production of nitric acid, urea and Nitrogen
compounds. It is found in ice and refrigerated plants. It is used in household cleaning to remove
carbonate from hard water. Since Ammonia is a decomposition product from urea and protein, it is found
in wastewater. Many water treatment processes add ammonia to form monochloramine as part of the
disinfection process. Aquatic life also contribute to ammonia levels in a stream.
NH3 is the principle form of toxic Ammonia. It has been reported toxic to fresh water organisms at
Selectech
Page 3 of 4
concentrations of 0.53 to 22.8 mg / litre. Toxic levels are both pH and temperature dependent. Toxicity
increases as pH decreases and also as temperature decreases.
Fish exposed to low levels of Ammonia are more susceptible to bacterial infections, have low growth and
are stressed. Tissue changes in their gills, liver and kidneys may also occur. Ammonia is a killer when
present in higher concentrations and many unexplained losses have been caused by Ammonia. Toxic
concentrations of Ammonia in humans may cause loss of equilibrium, convulsions, coma and death.
Ammonia should be tested regularly and corrective measures taken as soon as ammonia is detected, to
prevent loss of aquatic life.
Criteria in South Africa:
Ammonia levels in ponds and fish tanks should be zero. When it is present, the fish in the system should
not be fed until the problem is corrected. In small systems, a water change will help and in larger ponds,
a 0-20-0 fertilizer may help.
Wastewater*
1.0mg / litre for discharge of effluent water to rivers
10.0mg / litre for discharge of effluent water to other areas
* DWA – Requirements for the Purification of waste water or effluent, Act No. 991 – 18 May 1984
Drinking water*
< 1.5 mg / litre Ammonia as N
* SANS 241-1: 2011 Drinking Water Standards
Erratum
In the article "Lead and Copper in Drinking Water" in the July
Newsletter, the Criteria we used for the South African water
standards (wastewater and drinking water) were outdated
(SANS 2005). I apologise for this error. Thank you to Sarel
Pieterse, the Head of the Water Laboratory, Cape Town
Municipality, for pointing this out.
Lovibond®
MD100
CODE: LO276070
These Standards were, in fact, improved on in SANS 241-1:
2011 South African National Standard drinking Water.
Here is the correct and updated verion:
Criteria in South Africa:
Lead
Copper
Wastewater:
Wastewater:
0.1 mg / litre for
discharge of effluent
water to rivers
0.02 mg / litre for
discharge of effluent
water to rivers
Selectech
Page 4 of 4
0.1 mg / litre for
discharge of effluent
water to other areas
1.0 mg / litre - for
discharge of effluent
water to other areas
Drinking water:
Drinking water:
Hand-held photometer that
is ideal for fast and
accurate testing of Free
Ammonia and
Monochloramine in water.
≤ 10 µg / litre
≤ 2000 µg / litre
More detail & specifications
More detail about SANS 241:2011 Drinking Water Quality
Compliance and 2014 Blue Drop Limits from DWA
Postal Address:
PO Box 532
Allensnek
1737, South Africa
This email was sent to [EMAIL],
If you would like to be removed from the
mailing list please click on the link below.
Unsubscribe
CONTACT US NOW FOR A
QUOTE
Send To A Friend
Update your profile
(Change your email address, name and more)
Tel: 011 - 475 8565
Fax: 011- 475 8530
Cell: 082- 475 8565
Email: [email protected]