Description

Under the New Zealand Drinking Water Standards 2005 any presence of coliforms is unacceptable for human consumption.

PROBLEM:
Roof water – Rainwater
Faecal matter due to birds, possums, cats, mice etc. on exposed roofs and guttering is likely to contain pathogenic organisms. Dust, dirt and general organic matter such as leaves and moss can collect on the roof and in the guttering. If you are like most of us and only clean out the guttering once a year then you will know about the putrid decaying matter that can build up. This produces a very nutrient rich ‘broth’ that encourages bacterial growth in storage tanks.

Surface water – Springs, streams, rivers, lakes and dams
This water is usually the most heavily contaminated with micro-organisms. Often the water is also more turbid than collected rainwater due to high suspended solids and silt from surface run-off, particularly after heavy rainfall. Faecal matter from wildlife, birds, and farm animals present in the catchment area, is likely to find its way into the water supply, and this always contains disease causing organisms.

Ground water – Springs, wells, bores
This water can often be contaminated by run-off, stock, underground seepage from septic tanks, oxidation ponds, or other sources. Faecal matter from wildlife, birds, and farm animals present in the catchment area, can also find its way into the water supply, and this always contains disease causing organisms.

SOLUTION:
The Ministry of Health recommends a 2-barrier approach for providing safe drinking water. The simplest solution for automatic, and nonchemical additive treatment regularly being adopted these days is cartridge filtration followed by Ultraviolet (UV) disinfection. This is a simple in-line system that is installed into the existing plumbing at the point of entry to ensure that all water is automatically treated and of potable grade.