About Sewage Treatment

You are new to domestic sewage treatment?

When you are considering upgrading your home, replacing failed septic tank / soak-away, or including a sewage treatment system in the design of your new home, a domestic sewage package plant should be considered an investment. However, you would need to scratch through a myriad of the different systems out there in the market, some may be ideal which will offer you genuine peace of mind, but others are nothing more than expensive septic tanks. And you will only know which - soon after the lawn has grown back.

And then there are those systems that are so complicated that trained technicians are required to service the plant every time. Load-shedding and power surges adversely affect electronics and specialist equipment, and are no more reliable than most other systems. They just become difficult to manage, particularly when the homeowner has left the overseeing of the system to the grounds man, or garden service.

So, sewage treatment systems should be simple electrical & mechanical designs.

The Stink Factor

When deciding what would be great looking equipment for your garden / factory / office / estate, you would be excused if you felt you didn’t want to see it. Hide it, bury it, surround it with bushes, and this we understand. These things stink, and it’s a reminder of what we waste. It is not something we need to see every day - right?

Wrong! In today’s lifestyle, we have come to the reality that our waste has some value, and particularly our domestic wastewater. Several Scarab clients have included our sewage systems as features when selling their properties, and it certainly is an asset, even offering images of the system.

Then, the fact that Scarab systems recycle all the wastewater in the house, to be reused for gardens, lawns, flower beds, washing cars and even return to toilets, for re-flushing, makes ownership of package treatment plants so attractive.

And the stink factor – yes, this has some negative perceptions, as sewage does stink. But only when it’s sewage. Once sewage becomes properly aerated, (the aerobic stage) the smell stops, leaving an almost odourless condition - an earthy smell. Quite pleasant! When raw sewage is open to the air, will it smell. The large municipal systems (WWTW) do smell, since they are primarily open sewers, and this technology is classified as “activated sludge”. Very few package plants are based on this technology, since no household is prepared to have open sewers outside their kitchen. This technology is best suited for large municipal flows from towns and cities.

So, if your system stinks, its not working.

The Right Size

Deciding on the correctly sized system, will be your first objective. All systems will be designed on type of sewage, and volumes (usually litres per day) and quoted as a daily flow (24 hours) since this is when the full day's cycle in calculated, including peak periods (breakfast, lunch and dinner) and the off peaks (mid-morning and mid-night). We use the SABS National Building Regulations (NBR) guidelines on water use. NBR suggests that each person could use up to 250 litres of water per day, which includes washing, showers, toilet, laundry cooking etc. A three bed-roomed house could have up to 6 people living there, and this water usage is around 1500 litres per day. Hotels, camp sites, retirement villages and hospitals have their own consumption rates.

But, speak to us and we will give you your daily water use figures.

Assets & Liabilities

If sewage treatment package plants are an asset, should we bury them? I would think not. Some designs promote an underground system, with neat plastic lids (inspection covers). One wonders what a lawnmower does to plastic thingies hiding in the grass. And when the 10-ton honey sucker arrives to de-sludge (this is a part of maintenance on all systems - even Scarab !) and fails to see plastic thingies covered near in the flower bed. If you going to spend the (un)reasonable fee for a sewage system, you would want to see the darn thing, right? And should there ever be a problem, and it leaks, you won’t know. You will continue to believe your asset is safe, and saving water, meanwhile its leaking. Serious repairs could require digging up your magical lawn, removing the system, and returning it back to operation. And in the meantime, raw sewage is floating into the neighbour's property.

All water is an asset, particularly when you have already paid for it, so keep it in a safe place.

Plastic Septic Tanks

Buried septic tank failures

We do have requests for plastic sewage treatment plants / septic tanks to be buried, and we understand the reasoning. However, based on our many years of experience, civilworks (concrete & clay) is the only reliable, safest, long term solution. Its easier (and cheaper) digging holes and burying plastic tanks, and anyone can do it. However, even the professionals get this wrong, as seen above. If you going to spend on a sewage system, get it right the first time. For advice, give us a call.

Buried Concrete & Plastic sewage systems

These underground sewage systems are favourites in Australia, but they are so much different. All our (SA) systems are either plastic, or fibre glass, but Ozzies are concrete, weighing maybe 6 tonnes. When they go in, they don’t ever come out. They don’t leak, implode, crack or float out the ground. But, they are a terrible design. Those down under are not too concerned about water quality.

“If it pretends to work, we will pretend to care”.

Sewage System

Sewage treatment system

Sewage System in Australia

Steel and Sewerage

Some sewerage treatment systems are supplied using shipping containers, and / or mild steel frameworks. Special coatings have been applied to metal parts, in the factory, which is essential, and offers great oxidization (rust) protection – while in the factory. These systems, do, however leave the factory, travel maybe 5000 - 10 000 kilometers, on dirt and dusty potholed tracks, through war zones, and flooded rivers to reach a remote mine-site in the African bush, where they get off loaded and reassembled using local inhabitants, without any damage to this coating? After 3 / 4years, the system is a rust bucket, and would require replacement – yet again. Manhandling these sewage systems in the factory are pretty easy, but on the remote mine-site, craneage is a must. The alternative - roto-moulded (plastic) tank systems, are easily manhandled into position. And they don’t rust, ever.

Most sewerage systems are manufactured using plastic roto-moulded tanks, although there are a few fibre-glass designs The roto-plastic base-material is flexible, U-V stabilized, tough and does not oxidize easily. The plastic itself is resistant to chemicals, sewage contaminants, and toxic / corrosive gasses. These tanks are easily welded, cut, and even shaped, often on site. We have repaired a few of our Scarab systems after damage occurred during delivery, and quite successfully.