Daisy Hill (Victoria) – Trihalomethanes
7 & 8 July 2008 Daisy Hill Customer Tap – Maryborough System Trihalomethanes 0.440mg/L. Commissioning of chloramination plant in November 2008 for water quality improvements. Informed DHS. One Section 22 submitted for all THM non-compliances expected to occur
until 30 August 2009. (CHW Water Quality Report 2008/9)
7 October 2008 Daisy Hill Customer Tap – Maryborough System Trihalomethanes 0.360mg/L Commissioning of chloramination plant in November 2008. Informed DHS. One Section 22 submitted for all THM non-compliances expected to occur until 30 November 2008. (CHW Water Quality Report 2008/9)
2008/9 Daisy Hill THM’s 0.42mg/L
2007/8 Daisy Hill THM’s 0.51mg/L
2014/15: Daisy Hill Trihalomethanes 0.26ug/L
Trihalomethanes Australian Guideline Level 0.25mg/L
Why and how are THMs formed?
“When chlorine is added to water with organic material, such as algae, river weeds, and decaying leaves, THMs are formed. Residual chlorine molecules react with this harmless organic material to form a group of chlorinated chemical compounds, THMs. They are tasteless and odourless, but harmful and potentially toxic. The quantity of by-products formed is determined by several factors, such as the amount and type of organic material present in water, temperature, pH, chlorine dosage, contact time available for chlorine, and bromide concentration in the water. The organic matter in water mainly consists of a) humic substance, which is the organic portion of soil that remains after prolonged microbial decomposition formed by the decay of leaves, wood, and other vegetable matter; and b) fulvic acid, which is a water soluble substance of low molecular weight that is derived from humus”. Source: https://water.epa.gov/drink/contaminants/index.cfm
Daisy Hill – Victoria – Turbidity
2008/09: Daisy Hill (Victoria) – Turbidity 8.1 NTU (Maximum detection during year)
Chlorine-resistant pathogen reduction: Where filtration alone is used as the water treatment
process to address identified risks from Cryptosporidium and Giardia, it is essential
that filtration is optimised and consequently the target for the turbidity of water leaving
individual filters should be less than 0.2 NTU, and should not exceed 0.5 NTU at any time
Disinfection: A turbidity of less than 1 NTU is desirable at the time of disinfection with
chlorine unless a higher value can be validated in a specific context.
Aesthetic: Based on aesthetic considerations, the turbidity should not exceed 5 NTU at the
consumer’s tap.
Daisy Hill – Victoria – Total Dissolved Solids
2008/9: Daisy Hill (Victoria) – Total Dissolved Solids 1550 mg/L
2009/10: Daisy Hill (Victoria) – Total Dissolved Solids 850 mg/L
2010/11: Daisy Hill (Victoria) – Total Dissolved Solids 900 mg/L
2015/16 Daisy Hill Total Dissolved Solids 700mg/L
2016/17Daisy Hill Total Dissolved Solids 700mg/L
GUIDELINE
“No specific health guideline value is provided for total dissolved solids (TDS), as there are no
health effects directly attributable to TDS. However for good palatability total dissolved solids
in drinking water should not exceed 600 mg/L.
Total dissolved solids (TDS) consist of inorganic salts and small amounts of organic matter that are dissolved in water. Clay particles, colloidal iron and manganese oxides and silica, fine enough to pass through a 0.45 micron filter membrane can also contribute to total dissolved solids.
Total dissolved solids comprise: sodium, potassium, calcium, magnesium, chloride, sulfate, bicarbonate, carbonate, silica, organic matter, fluoride, iron, manganese, nitrate, nitrite and phosphates…” Australian Drinking Water Guidelines 2011
Daisy Hill – Victoria – Hardness
2008/09: Daisy Hill (Victoria) – Hardness 790mg/L
2009/10: Daisy Hill (Victoria) – Hardness 380mg/L
2010/11: Daisy Hill (Victoria) – Hardness 420mg/L
2013/14: Daisy Hill Hardness 210mg/L
2014/15: Daisy Hill Hardness 290ug/L
2015/16 Daisy Hill Hardness 390mg/L
2016/17: Daisy Hill Hardness 380mg/L
2018/19: Daisy Hill Hardness 220mg/L
GUIDELINE
“To minimise undesirable build‑up of scale in hot water systems, total hardness (as calcium
carbonate) in drinking water should not exceed 200 mg/L.
Hard water requires more soap than soft water to obtain a lather. It can also cause scale to form on hot water pipes and fittings. Hardness is caused primarily by the presence of calcium and magnesium ions, although other cations such as strontium, iron, manganese and barium can also contribute.”
Australian Drinking Water Guidelines 2011
Daisy Hill – Victoria – Iron
2008/09: Daisy Hill (Victoria) – Iron 0.37mg/L (Highest level only)
Based on aesthetic considerations (precipitation of iron from solution and taste),
the concentration of iron in drinking water should not exceed 0.3 mg/L.
No health-based guideline value has been set for iron.
Iron has a taste threshold of about 0.3 mg/L in water, and becomes objectionable above 3 mg/L. High iron concentrations give water an undesirable rust-brown appearance and can cause staining of laundry and plumbing fittings, fouling of ion-exchange softeners, and blockages in irrigation systems. Growths of iron bacteria, which concentrate iron, may cause taste and odour problems and lead to pipe restrictions, blockages and corrosion. ADWG 2011
Daisy Hill (Victoria) – Copper
2008/09: Daisy Hill (Victoriia) Copper 1.2mg/L
Based on health considerations, the concentration of copper in drinking water should not
exceed 2 mg/L.
Based on aesthetic considerations, the concentration of copper in drinking water should
not exceed 1 mg/L.
Copper is widely distributed in rocks and soils as carbonate and sulfide minerals.
Copper is relatively resistant to corrosion and is used in domestic water supply pipes and fittings. It is also used in the electroplating and chemical industries, and in many household goods. Copper sulfate is used extensively to control the growth of algae in water storages.
Copper is present in uncontaminated surface waters at very low concentrations, usually less than 0.01 mg/L. The concentration can rise substantially when water with a low pH and hardness remains in stagnant contact with copper pipes and fittings. Under these conditions, the concentration of copper can reach 5 mg/L or higher. In one extreme case overseas, a concentration of 22 mg/L was reported.
Daisy Hill (Victoria) – pH (alkaline)
Average pH: 2017-18: 8.8 pH units
Average pH: 2018-19: 8.7 pH units
Average pH: 2020-21: 8.7 pH units
Based on the need to reduce corrosion and encrustation in pipes and fittings, the pH of
drinking water should be between 6.5 and 8.5.
New concrete tanks and cement-mortar lined pipes can significantly increase pH and
a value up to 9.2 may be tolerated, provided monitoring indicates no deterioration in
microbiological quality.
pH is a measure of the hydrogen ion concentration of water. It is measured on a logarithmic scale from 0 to 14. A pH of 7 is neutral, greater than 7 is alkaline, and less than 7 is acidic.
One of the major objectives in controlling pH is to minimise corrosion and encrustation in pipes and fittings. Corrosion can be reduced by the formation of a protective layer of calcium carbonate on the inside of the pipe or fitting, and the formation of this layer is affected by pH, temperature, the availability of calcium (hardness) and carbon dioxide. If the water is too alkaline (above pH 8.5), the rapid deposition and build-up of calcium carbonate that can result may eventually block the pipe.