Farm Ireland

Sunday 4 December 2016

Filtration systems a crucial part of keeping supply clean

Units can remove all major hazards

Bruce Lett

Published 15/06/2010 | 05:00

WATER is an essential requirement for both man and beast. Once a well is drilled, getting it to the surface and furnishing a reliable and safe supply can require some sophisticated equipment. The traditional system was an above-ground pump mounted on a steel pressurised tank with a bladder inside it.

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These were usually siphon-type pumping systems, of which there are many still out there -- you can still get them new.

Essentially, the electrically driven pump circulated water around a loop, down a small pipe and through a foot valve in the well and back up the larger pipe to the tank. There is more room for the water going back up the bigger pipe from the foot valve in the well and this creates a vacuum, drawing water out of the well and depositing it into the bladder in the pressurised water vessel.

The water pump fills this bladder until the preset pressure at the pressure switch is reached, thereby cutting out the pump motor. The air pressure in the steel tank then squeezes the bladder full of water to supply it around the farm or house.

As the bladder empties, the pressure drops inside the cylinder until the pressure switch again switches on the electrically driven pump to again refill the bladder. And so the pumping and supply process continues.

Today the submersible is perhaps the most common of all water pumps found across the country. They are as a rule extremely reliable and durable, capable of pumping large amounts of water over long periods of time. There is only one water pipe required down the well (plus power cable), so they are easier to install.

The pump is only one part of the water supply system; above ground is the pressure vessel and perhaps water treatment or filtration systems.

To get an idea of what water systems, in terms of filtration and treatment, are available and what they might cost, I called into Pat Conroy in Camolin, Co Wexford, who has many years' experience supplying and installing pumping and filtration systems.

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One of his customers had problems with bacteria in the water as well as iron and manganese. Pat equipped the supply with an iron/manganese filtration system and UV filter directly after the pump.

"Iron and manganese will cause a discolouration in clothes," explains Pat. "The filtration unit will take both out of the water supply."

The large blue cylinder contains a product called Crystal-Right, silica crystals that filter both iron and manganese contaminants out. To the right of this is a rectangular blue bin containing coarse granular salt.

"The iron/manganese filter requires maintaining. It uses the coarse granular salt to clean the Crystal-Right media in a back-wash system. This is automatically performed at night-time and the wash runs out to a drain," says Pat.

The cost will depend on the system installed, he explains.

"You are looking at around €1,350 to €1,550. An average domestic system will use about one 25kg bag (€9-10) of salt per month," he says.

"For lime and nitrates in the water there is a similar system to the iron/manganese unit which is about half the height but it uses a different media for lime and again a different media for nitrates. They all use salt for the back-washing cleaning system.

"Price installed is €800-900 for the lime or nitrates unit."

The UV filter fitted to his customers' water supply is used to kill harmful bacteria.

Pat explains: "Basically how the UV filter works is that there is a glass liner inside the unit with a UV bulb in it. The water passes over the glass liner and the UV light kills the bacteria."

There is some maintenance required for the UV filter as well.

"The UV filter has a pre-filter (white unit) which filters the impurities out of the water so they do not coat the glass and block the UV light. A cartridge in the pre-filter unit needs to be changed every three months. This costs about €6," Pat explains.

For people with acidic water problems, blue stains on sinks and short life of copper cylinders, Pat's solution is a dosing system. This is also fitted in the pump house before the water reaches the consumer.

The dosing system adds a measured amount of a liquid product called pH Plus to the water supply to adjust the pH. The installed price is around €800. A 20l drum of pH Plus costs in the region of €60.

In an application for a grant for a new well and water supply, the county council will test the water and could insist on the use of a treatment such as those above.

In the case of a farm supply, it would not be necessary to treat the supply around the farm, just the water for domestic consumption.

For an average 0.75hp domestic submersible water pump (including tank) installation Pat quoted me a price of €1,000 installed. For an average farm application with 1hp submersible pump and bigger tank Pat quotes about €1,200 installed. Prices vary depending on the depth of the well. All Pat's prices include VAT.

Irish Independent