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Powders-NOV09

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Greywater

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New Zealand

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Water balance

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Greywater

Caravans

 Phosphorus calculations

GREYWATER FROM CARAVANS

INTRODUCTION

You may need to read the terms and definitions for 'greywater' as outlined on previous pages. The most important issue to consider is the quality of the greywater with which you are concerned.  Greywater from caravans will generally include the kitchen sink wastewater as well as from the shower and hand basin, but may also include disposal of water from clothes that are washed in a bucket and the wastewater added to the total greywater load. What you do with the bucket of water in which you have washed some clothes is equally as important as the disposal of water from the shower or kitchen.

We, therefore, need to modify our general perception of greywater quality both in terms of quantity (litres per day) and chemistry (concentrations).  The greywater from a domestic residence is NOT the same as the greywater from a caravan either in volume or quality.  Indeed, because of the low water use in a caravan, but a similar use of soap (for showering) or kitchen chemicals (dishwashing detergents), oils and greases, the concentration of nutrients (nitrogen and phosphorus) and contaminants (sodium, bacteria and many other chemicals) is likely to be significantly different to the domestic situation.

QUALITY OF GREYWATER

Certainly caravaners are aware that the quality of town water may vary considerably from town to town. Some town water supplies are very soft and others very hard, depending upon the source of the water,  the geology of the aquifer (for bore and spring water) or geology of the catchment  (surface and river waters).  Therefore, the quality of the greywater will vary with each load of clean water taken on board.  Rainwater is essentially the same across the country and very soft. Minor variations in the small concentration of calcium and sodium in rain water will occur due to distance from the oceans.

Next items to consider are the type and quantity of additives to the water that occur when the clean water is used for showering, hand washing, clothes washing or in the kitchen. Do you use the same harsh chemicals in your touring as you do at home? Do you have the same range of bathroom chemicals - soaps, body washes, hair care products, deodorants, talcum powders, anti-dandruff treatments, hair dyes, as you do at home?  If so, have you considered how the greywater that you generate may be entirely different from other caravaners simply based upon the different chemical mix you generate.

I dare not use the term "environmentally friendly" because as soon as you do anything to the water it may become very unfriendly. As an example, you pour the hot water off the vegetables down the kitchen sink and this greywater dribbles out into a well prepared area on the adjacent soil, perhaps around a tree. The change in temperature of the water, the chemicals boiled out of the vegetables (we used to use this water to make soup) could hardly be called 'friendly' to an earthworm or ant - so let's avoid such terms.  Think of the consequences of the chemicals and address the disposal in a responsible manner.

The quality of the greywater becomes irrelevant when you ALWAYS discharge all your greywater at an approved 'dump point', where the greywater is added to a municipal sewerage scheme and treated with other domestic wastewater. It now becomes someone else's problem and it has had to be engineered to accept the blackwater slug.  The operative word is ALWAYS.  To do so, you must carry all the greywater you generated between approved dump points and not discharge any greywater to the general environment, including the bucket of water in which you washed your singlet and undies, or the cup of water you used when brushing your teeth - after all, it's all greywater.

However, touring is not as clear cut as having sufficient dump points to suit your itinerary. So you must consider the options for discharging your greywater, based upon its chemistry, not just the volume. Now you need to know what chemicals you have added.

I suggest that in preparing your lists of 'what should I take' and 'what don't I need to pack', you may find it a pleasant surprise when you can leave at home many of the chemicals you have been used to using in the home.  Look at the label of these products and discard any that contain products that may harm the soil environment - the ants, the worms, the soil bacteria and fungi, all of which are part of the production and degradation processes that occur in soils.

Does the toothpaste contain triclosan - a very strong antiseptic used in hospitals?  Have you left the chlorine bleaches at home?  Is the laundry product low in sodium?  Have you considered using the same liquid detergent for washing up and clothes washing (just different amounts for each)?. Be aware that while bicarb soda is nominated by many alternative cleaning advocates, bicarb soda is sodium bicarbonate (27% sodium) and it is the sodium that may be the problem. When you use laundry detergents that contain phosphorus, you have to be careful that in disposing of the greywater, that the greywater does not get into streams or waterways.   See under the various headings in "Laundry" to choose products that are low in both sodium and phosphorus as well as having a low pH. There are such products and these are the ones that would be better used when travelling.  Anti-dandruff treatments (selenium), zinc cream (zinc), anti-iching powders (zinc) and even talcum powder (aluminium) can be disastrous to the soil environment.

You will be surprised when you start checking the labels on the chemicals you pack.  It's a bit like looking for 'sugar' marked on food products. When you start looking you realise how prolific some of the nasty chemicals are.  Look out for the products marked as 'antiseptics', 'anti-bacterials', 'kills germs', 'sanitises', 'disinfects'.  They all mean that these products will kill, or harm, the soil environment in some way. And just because a product contains 'citric acid' or 'eucalyptus' doesn't mean that it will not affect the soil microbes or the plants.  Just be aware!

Bucketing Greywater
In most states, an exemption to the disposal of greywater exists when that greywater is collected in a bucket and spread manually on lawns and gardens. Greywater from the shower, the bath tub or the laundry water is able to be spread without any approval from local government.  There are no conditions on how that water is to be collected, carried (other than in a bucket), spread (at what rate of application (litres per square metre)), or how often it is spread over the same small area of lawn or garden. One can take the wash water from the washing machine complete with its chemical load of detergent and dispose of it in the garden, provided you do so using a bucket or two.  However, in NSW it is illegal to pump the water out of the same clothes washing machine and spread it over the surface of the lawn or garden using a pipe.  Why?  Who knows?   I certainly don't see the distinction when you may be talking about the exact same quantity and quality of water from the same source.

For the caravaners, one would expect the same exemption to apply.  That is, provided you bucket the greywater onto adjacent lawns, gardens, trees or shrubs, all should be okay and you can spread the greywater over the surface of the soil. I hope that you would do so with some consideration of the consequences of that greywater not entering a stream or river, or not causing the water to pool.  I also hope that you will have removed coarse solids from the greywater, by filtration, that may attract vermin (rats, flies, mosquitoes).

OPTIONS FOR GREYWATER DISPOSAL (outside commercial caravan parks)

Option 1. Collect all wastewater generated within the caravan in a dedicated greywater tank. Only discharge that greywater at an approved dump point, including water used to flush the tank and delivery pipe.  This option means that you now have to carry all your greywater to a dump site - perhaps driving miles off your predetermined course because of the scarcity of approved dump site.  What do you do when you cannot off-load the greywater?  Doesn't that means you have to have an alternative position - discharge to land.

Option 2. Collect the wastewater from the kitchen for storage in the greywater tank, firstly removing as much of the solids as possible.  Discharge this load at an approved dump point.  Discharge the shower water onto the ground away from your caravan and other future users of the camping site.  This option means that you are carrying only a small portion of your daily water use, usually the worst for quality because of fats and greases and washings of vegetables.

Option 3. Follow 'best management practices' in the generation of greywater, its pre-treatment and ultimate discharge to the environment to minimise risk to public health and the environment. Many would consider this the 'pro-active' approach, considering the opportunities and minimising the risk.  Thus, when Option 1 fails, you have an alternative that you could have used in the first place, except where local disposal is prohibited.  This option doesn't prevent you from installing an effluent tank and using it when circumstances demand, but it does make you aware of your responsibilities in local discharge situations.

Option 4. Do nothing and wait for the regulators to force you to undertake either expensive modifications or site exclusions you will live to regret. Contribute to be part of the solution, not the reason for regulation. Don't expect the regulators to have your interests at heart, or to even understand your motivations for caravaning.  And once regulations are passed, don't expect them to be changed.  I have been waiting since 1998 for the NSW Government to address some of the inaccuracies in their domestic wastewater guidelines - I haven't been holding my breath.

BEST MANAGEMENT PRACTICE (Option 3)

From my experience with collection, treatment and disposal of all types of wastewater, not just what some consider the innocuous greywater from a caravan, creating a set of 'best management practices' is the preferred option. After careful consideration of the type of greywater and various disposal options, opportunities for 'environmentally responsible' disposal can be  decided simply on a set of tick and flick criteria based upon the best available information for the water quality and location.  These 'best management practices' can cover many situations from no disposal to a free for all, but with each disposal being carried out in an environmentally responsible manner.  That means having regards to the quantity and quality of the greywater you are discharging, and minimising the public health aspects, environmental consequences and local area aesthetics for each disposal event.

 

THIS DOCUMENT IS A WORK IN PROGRESS