THE
USE OF SEPTIC TANKS AGAINST INSTALLING A FULL SEWAGE PLANT
In the past it has been customary to install septic tanks, conservancy
tanks or even pit latrines in many applications such as: housing
developments, schools, toll plazas, hotels and hospitals.
Over
the years the advantages and disadvantages of these installations
have been learned and a revaluation of the alternatives is required
in order to ensure that the people using the facilities are given
the correct system to both accommodate their needs and expectations
as well as ensuring that the environment is kept under consideration.
As
development increases, it is more and more important to consider
our ground water and rivers, as they are the life-blood for many
of our communities.
The
use of any system which pollutes the ground can only be used in
areas where the geological conditions are such that soak away
of the polluted effluent can occur safely and over long periods
of time. The re-siting of soak-away areas is becoming expensive
and normally it is experienced that this is not done, resulting
in serious pollution of the area.
Areas
where the ground water is very high or where clay or rocky ground
is present, are not suitable for soak-aways, and septic tanks
or similar should be avoided at all costs. Dolomite areas are
another area where septic tanks are problematic.
In
case of septic tanks it should be taken into account that if the
septic tank looses it's biological balance (due to the ingress
of poisonous materials), they can discharge their full sludge
content into the soak away area, blocking the soak-away and resulting
in straight outflow of the effluent.
It
must also be remembered that the sludge in septic tanks has to
be removed almost on a yearly basis, depending on the size of
the tank. So although the septic tank may be the cheapest short-term
solution from a capital point of view, it does not give the users
the advantages they are looking for. If all aspects of the system
are not fully considered carefully and/or maintenance is not done
on a yearly basis, septic tanks can become an operational and
expensive problem.
It
is for these reasons that many septic tank installations have
shown problems in the past, whereas others have given the service
they were designed for.
The
use of conservancy tanks is from an environmental point of view
excellent, as no local pollution occurs. However with the current
pressure on operating costs on both municipalities and organisations,
the continuous emptying of conservancy tanks has become a financial
nightmare. If not emptied regularly, they become a major environmental
disaster, as untreated sewage will enter the soil.
Also
very often overlooked is that when plastic septic tanks are used
as conservancy tanks, these are not designed for running empty
underground. All plastic tanks are designed to operate full of
liquid only, and if emptied at a time of high water table, these
tanks will collapse.
The
use of small sewage plants is becoming more and more feasible
because of both the needs of the consumer, the needs of the environment
as well as the pressure of operating costs.
The
Siyageza range of sewage plants marketed under the trade name
Biogeza Systems offers a full range of plants designed
for the specific application, but still standardised so that costs
are minimised.
The
Biogeza Systems are low cost and easy to operate. They
do require a commitment by the end user to check the operation
regularly so that the plant remains operational. But as operation
is simple, any community large or small is able to maintain the
plant operational at all times.
The
system is based on an activated sludge design, which is the same
system used for larger sewage plants worldwide. The process is
simple and the efficiency can be guaranteed. The fact that complete
units can be supplied from R15 000 upwards, has opened many areas,
including individual houses.
Effluent is guaranteed under normal operational conditions to
be well within the current national and international specification
of General Standard, which is suitable for irrigation or discharge
in waterways.
If
one takes into account that the water produced by the plants can
be used for irrigation, the cost of the plant is usually covered
over a few years by the water savings for the community. As the
water is available, it is a bonus to be able to use it and even
if the water is essentially free, the fact that gardens can be
irrigated, improves the overall environment of the community.
The sludge produced by the plant can be dried on site and used
as fertiliser for gardens. A new dewatering system is being introduced
to make this operation even simpler.
The
new generation of Biogeza sewage plants thus offers the
designer and the user many opportunities:
- Improve the living conditions of our communities
- Reduce pollution of our country and our rivers and ground water
- Improving the health of our people by ensuring safe water supplies
- Reduce water costs
- Reduce collection costs of sewage
