Archive for August, 2009

Boosted reverse osmosis filter for farms

Friday, August 21st, 2009

One of the problems with many homes in rural areas is that there is not enough pressure from pressure pumps to run a reverse osmosis filter system. Reverse osmosis filters work by pushing water against a very fine membrane. Only a proportion of the water, usually 1/4 to 1/3 gets through, leaving behind most salts and other contaminants.  The rest of the water with the contaminants goes to waste.

A boosted RO system for rural homes.

A boosted RO system for rural homes.

RO systems are designed to remove a large proportion of most contaminants from water including salts and chemicals. The result is very clean water. RO works more efficiently with reasonably clean water like rain water tank or spring water.

The picture is of a boosted RO I made up. It is in the lab and produces rinsing water for the lab and also drinking water for the house. Output is about 108 l/d. It uses a 24 gpd membrane. 50 gpd membranes are also commonly used. The prefilter is just a 1 micron sediment cartridge. The second cartridge is a 1 micron carbon block cartridge. This cartridge is designed to reduce tastes, smells and protozoan pathogens. Here are some results for the lab RO system.

Before filter After filter
DOC* by UVA 254 nm 2.1 ppm 0
Conductivity 87 microS/cm 7.4 microS/cm

* DOC = Dissolved Organic Carbon. DOC is directly proportional to UVA at 254 nm for most waters. Here an estimate of DOC is made based on an approximate relationship derived from published data from a variety of waters.

There are no detectable dissolved organics getting through and the salts level has been significantly reduced. RO membranes can also reduce bacteria in the water but I haven’t tested bacteria reduction yet.

For a range of water filters to suit both town and country applications see Water Doctor water filters.

Trip to Mt Erica

Monday, August 17th, 2009

Last weekend I joined a few of my ex Rover friends from the Yallourn Capt Hurley Rover Crew on a trip up “The Mountain”. The mountain is Mt Erica in Gippsland. Most of us are in our late 50’s or early 60’s. We have mostly known each other for over 40 years.

Mt Erica Aug 09

Our numbers were a bit down this year but here are the diehards at the summit of Mt Erica.

The Captain Hurley Rover crew built the JW McMahon hut on Mt Erica over many years starting from 1938. Its a basic but comfortable mountain retreat. It has given generations of scouts and other groups the opportunity to take time out in a relatively unspoilt and remote area in a safe way. From Mt Erica we can look down on the expansive Latrobe Valley with its several coal fired power stations. So close but a world away. The water on the mountain tends to be fairly clear with relatively low numbers of bacteria. In other similar hilly areas I’ve measured low organics in water using UV but this is mostly humic material.

There wasn’t much snow around this year. Global warming perhaps? Its often difficult to use scientific knowledge to prove that one factor is causing another so arguments tend to go round in circles. In the medical field there have been attempts to move towards a type of diagnosis that attempts to describe the patient’s current ‘situation’ and to infer how the patient’s overall condition has developed. Its like trying to explain something and the explanation is a model that is further tested and refined. Part of that refinement is through the treatments themselves.  Perhaps environmental problems could be tackled the same way.

We spent a pleasant couple of days together with no electricity (well except for batteries to play the iPod), no emails, no showers and only the company of Boris the resident Lodge rat.