Treating water means making it safe to return to the environment. ‘Safe’ has different definitions from country to country but basically you know when your sewerage water or ‘grey water’ is insufficiently cleaned when there are always seagulls around the local sewage outfall. Maybe some authorities consider that feeding fish is part of the chain in waste degradation, but fish do not necessarily live on harmful bacteria so this is going to be detrimental to water quality and health.
Water treatment, no matter where you are in the World, employs exactly the same processes seen in nature. There are systems that, to the untrained eye, don’t actually appear to be a water treatment facility at all, because they just look like a series of reed-beds, ponds and lakes. It’s a pity that these ponds are dug in such mathematical shapes really. Usually, these natural systems cater for low flows of effluent from villages and small populations and for remote locations there are some man-made devices that contain nature’s capacity to degrade our waste. The natural solutions are the ones embraced and promoted by this site but it is a sad fact that with the sheer number of people on the planet, we would easily inundate ourselves with our wastes if there were no effluent systems operated on a city scale.
Nonetheless, these city wide treatment plants are responsible for the treatment of the vast majority of our effluent and there is good news that they are becoming more effective through technology. But before I go into a brief explanation of municipal systems, let’s look at how nature deals with her wastes and how we take advantage of this.
Small Scale Systems
Nature can handle raw pollution very well thank you very much. Nature is devoted to handling life and death on a massive scale and mankind has developed systems that are in tune with just how much death nature can cope with without actually affecting it negatively. Clearly, our human activities end up concentrating our waste so much that nature’s processes would cease, although we do help nature’s processes by removing as much of the obvious effluent as possible. This is called primary treatment and basically this is the removal of waste that can be picked up with a machine. Remember that the process is all about being able to reclaim as much water as possible and then being able to remove bacteria from that water.
Simply speaking, the secondary treatment of this sieved water involves using natural ponds or man-made tanks to allow more of the undesirable particles to settle to the bottom and for the resulting water to return to nature. These are some of the systems typically available to handle effluent from just one house up to a small community.
Reed Bed Systems:
www.arknursery.ie - reed-bed filtration IRELAND
www.ltluk.com - natural wastewater treatment UK
www.waterrecycling.com - water treatment US
If you have access to areas of land then have a look at:
www.drip-tech.com - wastewater treatment through soils US
www.humboldt.edu/~ere_dept/marsh/flow1.html - the story of a water droplet through a natural water treatment system in the US. Easy to understand.
For typical man made systems see:
www.johnstonsmith.co.uk - typical effluent treatment systems UK
www.thenaturalhome.com/septic.html - septic tanks and home wastewater treatment US
In The Bahamas, waste is passed through a cess tank and then fed directly back into the ground albeit at a lower level than the drinking water is extracted. As the water percolates through the rock, it is cleaned of enough waste to render it fit for drinking and all the tests prove it. There are many ways to treat water it seems.
Once the treated water goes through the rain, rivers, reservoir cycle and ends up back in your pipes, you may wish to treat the water further by purification, not because the original human pollutants are still left in the water, but because nature has a habit of producing locally abundant ‘toxins’ that may affect your water. The benefits of Ultra Violet light and Ozone have recently come to the fore concerning removing bacterial pollution and there are some other easy to fit devices you can see in our Products section. Some of the most modern technology for home treatment is from Sylvan at www.sylvansource.com
In circumstances where waters become polluted in rivers and lakes, and in the sea from oil companies, the clean-up is a bit harder to do. This site is not going to delve into what is termed remediation, or cleaning the mess up, but there seem to be other ways that we can further improve our environment. I remember hearing a guy telling me that his company was developing a seaweed product to help clean up the seas simply because he had noticed that the sea around his cliff top home was always much clearer than anywhere else and that he had gone on to prove the powers of seaweed were significant. I can’t find those specific details but here’s some food for thought.
www.g-forse.com/ - ash blocks make reef come alive
www.taskelp.com - seaweed as a fertiliser
Municipal Systems
Municipal systems ultimately use nature itself to cleanse our wastes except that nature’s activities have essentially been squeezed into a supremely efficient production line. Filter beds full of porous stone alive with amoebas, protozoans and fungi get fed on our waste and hey presto, the end product gets returned to nature. Still, reducing 10000 gallons of pure and unadulterated @@@@ to more or less drinking water is no mean feat.
Firstly, the effluent (a mixture of kitchen and bathroom waste – grey water, and human waste – black water) arrives by pipeline after being pumped from various collection points in the sewerage system. Blockages can be very frustrating. Similar to the small scale systems, it is screened to remove large items which are then taken to the municipal tip. The secondary system in nature’s way is to allow the concoction time to settle, whereas our industrial fast track process adds chemicals that cause the various particles to flocculate or stick together, making them easier to remove mechanically. I have also seen the use of a specially constructed deep shaft. As the effluent falls, further separation occurs and the resulting mess at the bottom can be divided into liquids which pass into the filter beds, or sludge, which is cleaned away for removal to another bacterial process which actually converts it to compost. Yes that’s true. Now eat your carrots.
www.greywater.com - a unique approach from Sweden.
Most of the degradation of this sludge happens in digesters. What a great name and yes they do produce gas. Either the sludge goes into an airtight tank where it degrades anaerobically (without oxygen) with one type of bacteria and produces methane, or it goes into an aerobic (with oxygen) tank with other bacteria and produces the usual bacterial waste of CO2. In nature’s way, the anaerobic digestion takes place at the bottom of the pond, with no oxygen, or aerobically with algae on the surface. Those bubbles you see that you reckon are frogs are just bubbles of methane escaping. Large municipal systems capture the methane for CHP power plants or to burn it off. Methane is a greenhouse gas and considered six times worse than CO2.
Meanwhile, the liquid part is fed into the filter beds which can be aerated and heated to improve their performance, and after being tested to reach a certain quality (content of undesirable bacteria) the water, as it can now be called, is then passed into nature via the infamous sewage outfall. In periods of heavy rain the whole system can become inundated and to relieve the flow, there is a bypass in place where raw sewage can avoid treatment and end up directly in the sea.
Understanding the Anaerobic and the Aerobic processes can be seen at:
www.biotank.co.uk/aerobic.htm
This is the system that has been used in the UK to return its previously disgusting beaches to ones that get awards for cleanliness. And it has not taken that long really but it has cost a lot of money.
Problems arise when the microbial life in the filter beds gets poisoned because petrol spillages, industrial chemicals and heavy metal pollution somehow enter the sewerage system. Our effluent systems are well attuned to removing our natural wastes but not so, the various carcinogens and gender changing compounds for which we have the chemical industry to thank. Someone once referred to this ‘necessary’ pollution as progress. Getting rid of these compounds is difficult because they never degrade.
The good news is that the technology that has been used to clean up especially polluted sites like old chemical factories (bioremediation), is now being introduced into the most modern effluent plants. Using membranes and biofilms to do this is not really experimental bit it is hardly mainstream just yet. For the meantime then, we will just have to accept that increasing levels of cadmium in our blood will continue. And mercury and chrome and lead. Brains and organs are excellent places to find heavy metals. In the next section on Water Quality it seems evident that our pollution is not just confined to heavy metals.
www.bioremediationgroup.org/ - remediation technology
The only advice needed if you are part of the municipal sewerage system is to treat it responsibly. Don’t put inorganic things down the toilet and ask your mother to stop using bleaches and chemicals as much as she does. Clean her house and oven may be, but if someone in the family has Tourette’s syndrome then use her chemical consumption as the reason for this. Try anyway.
