Wetlands - Natures Kidneys

When we see a natural wetland system, we tend to see an area of beauty, teeming with plant and animal life. These wetlands are areas that naturally collect water from ground runoff, streams and rivers. Along with this water comes natural 'pollution', animal and plant waste, decomposing matter etc.

A natural wetland has an inherent ability to reduce the impurities in the waters. Wetlands have been shown to reduce levels of Biochemical Oxidation Demand, Suspended Solids, Nitrogens, Pathogens, Metals, Phosphates and Trace Organics.

UMMERA Constructed Wetlands - The Purpose
The objective of the Ummera Smoked Products wetland system is to emulate a natural system, harnessing both natural 'pollution' mentioned above and liquid waste from the smokery to create an aesthetic, low cost, yet effective treatment facility, which compliments the natural local flora and fauna.

The system is supported by complimentary technologies, which aid the natural process.

It is important to note that our Ummera effluent is almost totally organic in nature, and is therefore very suitable for wetland treatment.

The Ummera wetland system is designed to produce a final effluent with a BOD of below 5mg/l, this is equivalent to the standard of 'fresh' water required in salmanoid rivers. This is cleaner than present measures of water quality in the Argideen River.

System Description
The system comprises of three main components

1. Septic Tank: The first stage of the process uses sedimentation (reducing solids quickly) and anaerobic action to start the sewage reduction process. This primary treatment is very effective, reducing sewage strength by up to 50%.

2. Aerobic Facultative Pond: This pond is designed to allow aerobic conditions to develop in the wastewater, encouraging algal growth, in preparation for passing into the actual wetland surface flow system.

3. Surface Flow Wetland 'Ponds': The wetlands receive oxygen and algal rich sewage from the aerobic pond. As this flows through the series of wetland ponds a series of natural activities 'purifies' the sewage.

· Settleable and Suspended Solids that have not been removed in the pre-treatment (septic tank) are removed by filtration and sedimentation, as the liquid moves slowly through the pond system. Sedimented sludges are subject to microbial action.
· Sludge and Soluble Organics are mostly degraded by microbes (growing on plant stems). The gas transfer up (CO2) and down (O2) the plant stem assists the process. Whilst some nutrient is taken up by plants, this is not a major part of the process.
· Nitrogen is primarily removed by microbial Nitrification-Denitrification mechanisms and Volatilisation in open water areas.
· Pathogens are also removed by filtration and sedimentation. Throughout the wetland they are generally subject to hostile conditions (including natural UV light) leading to high die off.

It can be seen that the system is simple, low cost and aesthetically pleasing. It fits well with the local environment, complimenting the natural wetland in which it is located. The size of the system acts as a buffer for varying amounts of wastewater; the lack of mechanical or electrical plant reduces breakdown risk.

For operations of our type and size, constructed wetlands would appear to be an excellent alternative technology.