This invention relates to distribution of aqueous fluid into an underground soakage situation in such a way as to lessen the possibility of such an arrangement being eventually blocked by root growth.

5. The invention accordingly can reside in the method of distributing such aqueous fluid to achieve such purpose and also an arrangement including apparatus specifically of value in achieving both the arrangement and the method.

10. It is a well known and indeed enormously difficult problem that wherever aqueous fluid is introduced throug- h any passageway or conduits into an underground soakage situation that these seem to be highly vulnerable to being blocked by root growth from plants .

15. It is perhaps self evident that it is in the first instance of significant value to have roots in the vicinity and intimately mixed with a soakage area but at the same time it is generally considered intolerable to have this simply because the roots after a reasonably

20. short period of time seem inevitably to build up and eventually block any supply conduit to provide the aqueous fluid access to the soakage area.

The problem of course does not relate to any particular type of installation presently used but 25. relates to any installation where an aqueous fluid perhaps simply water, or in a more common case effluent from a septic treatment tank is to be disposed of or at least dispersed within surrounding soil which is first achieved by soakage.

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On investigation of many instances of root blockage conventional soakage distribution installations associat with septic tanks, I have noticed firstly a characterist shape of the roots as they bunch around specific are 5. associated, with the soakage areas and I secondly ha noticed a certain amount of dead growth mixed within t live roots so that the entanglement becomes more fixed a more difficult to subsequently remove.

It seems therefore that the promotion of growth a

10. the subsequent removal of water within a certain vicini may have an effect of killing some of the root en promoting blocking from the resultant dead roots stayi within the same location.

Also, considering the rate of root growth, t

15. capacity for certain conditions to attract root grow while other conditions would seem to deter root growth, have generally discovered a quite distinctive arrangeme which appears to in some senses completely go opposite conventional thinking with regard to soakage principles b

20. which in experiments conducted thus far have resulted very significant retardation of any root growth into vulnerable location with respect to blocking of a supp conduit and thereby promoting the possibility of havi even most aggressively growing roots of trees in the ve

25. adjacent vicinity of a water soakage area without at lea at the present time expecting to have to clear t passageways as often has hitherto been the case.

Indeed, with respect to a preferred embodiment, it would seem a significant period of time can now be achieved whereby soakage can be effected in the close vicinity of aggressively growing trees without rapid blocking of the 5. supply conduit by root growth into these and as has hitherto been explained "die back" of the roots.

A first discovery has been that root growth will only generally be promoted within a modest degree of saturation of the soil but is not promoted If the soil is generally 10. saturated and likewise if the soil is generally dry.

This character of soil which has sufficient moisture of an. adequate type to encourage root growth is generally called herein earth having a "field" capacity.

If then a system could be devised in which in terms of

15. time and terms of volume soil at field capacity could be kept to an absolute minimum, it may be then generally possible to inhibit root growth into the main area of the conduit and hence achieve the answer to the problem set.

It has been discovered how this field capacity area 20. can be kept to a minimum both in terms of time and in terms of volume and as such this has greatly inhibited potential root growth.

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V/IPO

It has been further discovered that certa characteristics of aqueous fluid such as when this in so instances emanates from a septic tank has a characterist which actively inhibits root growth seeking this particul

5. fluid.

I have discovered that this relates to the anaerob character of the fluid and according to this inventi there is proposed an arrangement and method whereby duri soakage the anaerobic character of the fluid is general

10. attempted to be maintained.

A further inhibiting factor has been found in that a airspace even though this is completely in the dark a withi_a a moist environment, there is a greater than selected „ percentage of carbon dioxide and or carb

15. monoxide then this also will inhibit root growth into th area. Accordingly, with liquid effluent, by having t liquid fed into a closed area, that working in the flu will continue to use such oxygen as remains within t fluid but at the same time expel such by-products as carb

20. dioxide into the enclosed airspace such that this th promotes a self induced inhibition to root growth in th other area.

Accordingly, by achieving inhibition in the three vulnerable areas namely the soil directly beneath the distribution passageway, inhibition of entry of roots into the fluid itself, and inhibition to roots into the airspace 5- above the liquid then it is generally realisable that for the first time known to the writer, it becomes feasible to provide soakage and indeed removal of aqueous fluid by using roots without these as actively as hitherto gaining 10• access to and blocking the supply conduit itself.

While each of these factors contribute to an advantage and the three contribute to significant advantage, it would appear that at least one of these in each case would promote inhibition and two out of the three would assist in

15. greater inhibition.

Accordingly there is advantage in using merely one of these concepts although it is significantly desirable to use all three.

In providing an arrangement by which these general

20. proposals can be achieved, it is interesting that it would seem that the arrangement of distribution passageways goes totally contrary to that which has been hitherto accepted as the norm.

To explain this further, I now propose that a soaka distribution passageway beneath the ground be arranged th the aqueous fluid fed into this will in effect pool at t initial entrance to the passageway which can be achieved 5. providing that the soakage floor of the distributi passageway rises as it leaves a distribution location.

This of course goes quite counter to convention teaching in which it is considered that distribution ov as great an area as possible by perhaps continual 10. allowing the total area to be used and for the liquid to distributed regularly and caused to flow over the who area is the preferred method.

The pooling effect can be achieved by providing plurality of successively arranged dams or weirs so th

15. the aqueous fluid is held in a dam condition with respe to a first weir until it reaches an upper level of the we and only then will proceed over to start to fill the seco weir area. As the height of the liquid rises, this wi hold all of the fluid back until collectively the heig

20. reaches the height of the second weir which arrangeme will have the result of causing a greater head of wat above the initial soakage area which will cause this push the water, out further into the sides of the passagew but limit access of the liquid to the next segment.

According to my experiments, such an arrangement significantly lessens the area of ground directly below a soakage passageway which will thereby be kept at field capacity this being as compared to previous techniques.

5 _# I have also found that by using such a pooling technique, and by ensuring that the water introduced over the soakage area from a relatively small surface area this has the effect of inducing more side soakage with the result that as the aqueous fluid soaks out to the side of

]_ _Q# the passageway this then enters ground which Is generally porous and connected to atmosphere through the porous structure of the soil and by reason of capillary attraction in the soil and by reason of this access through the porous structure, the water comprising the aqueous fluid becomes

3_5 _^ exposed to a significant quantity of air and becomes oxygenated that is aerobic and furthermore because of the character of the distribution there is much less saturation of the soil and the plants whether this be a tree or other growing plant can thereby proceed in conventional soil

20. structure and reach the deeper water which has reached a level of oxygen content sufficient to be of use to these roots .

It is of course a feature of the arrangement described that where the aqueous fluid is indeed a liquid effluent 25. from a sewage outflow typically from a septic tank or the like, this is conventionally active with bacteria actively growing within the effluent and the effect of this is to conventionally to use any available oxygen so rendering the liquid anaerobic.

Any exposure of the liquid to air and especially a turbulence or causing the effluent to flow through the a can change this anaerobic character and even sma quantities of oxygen are found to change this charact 5. significantly and to change the liquid from one that wi inhibit attraction of roots to one which will attract root

It is therefore a feature of this invention that t arrangement by which the fluid is fed to the soaka distribution passageway and through the passageway such 10. to minimise such disturbance and of course this significantly assisted by the pooling concept and providing weirs whereby to limit flow of the fluid ov roughened soakage ground which inherently cause turbulenc eddying and hence pick-up of oxygen.

5 _Φ Typically, the weirs are so shaped that they a inclined to the vertical so that any water or efflue flowing thereover will be caused to flow in as streamlin manner as is possible rather than being caused to free fa through the atmosphere.

20. The next problem relates to keeping the atmosphe that is the space above the soakage area and specifical above liquid introduced into the soakage distribution ar such that 'this also will inhibit root growth thereinto.

•

It has been discovered that by simply introducing or keeping this atmosphere replete with an adequate inhibiting gas and carbon dioxide seems to have this function, then once again not only is there no capability for support of 5. roots within the area but it seems that the roots themselves are inhibited from entering the space itself.

Accordingly this is best achieved by simply providing that the space as such is generally closed to atmosphere and is so arranged that even if there is an accesss to

10. atmosphere, this will not promote any throughflow ventilation.

Because it is sometimes necesssary in installations of this ^" type that access vents necessary, it is a preferable feature that the entrance into the distribution chamber be

15. such that as soon as the aqueous fluid is introduced into this, this will in effect close this off from acces to atmosphere so that in the least, whenever there is aqueous fluid within the system of even minor quantities, the distribution passageway will be effectively closed to

20. atmosphere.

It will be noted by those familiar with this art, that there would seem to be an apparent difficulty in providing such an arrangement in that there is an effective airlock by sealing what is in effect a closed end passageway into

25. which one must introduce fluid.

In practice, it is to be understood that the soaka ground itself essentially porous and to this extent t entrance of a fluid into the passageway when considered a chamber, will tend to cause expulsion of the air with 5. the passage through the natural infiltration through t ground enclosing at least part of the passageway.

Obviously however this will be slow and this in itse provides a good buffer so as to inhibit rapid movement fluid into the distribution chamber and hence this assis 10. in keeping the fluid in the case of effluent anaerobic.

It is to be noted, that whereas in a preferr arrangement, the passageway for distribution is risin where there are a plurality of weirs and preferably the held by an enclosing upper cowl, the actual floor of t 15. distribution providing the soakage can fall with respect the entrance although the effect with the weirs will be though the floor itself was rising in that the water wi be restrained and kept as a pool by reason of the weirs the entrance.

20. According to one form of this invention then it can said to reside in an installation for effecting dischar of aqueous fluid beneath the ground and removal by soaka in the vicinity of growing roots in the ground capable the said aqueous fluid, the arrangement being characteris

25. according to this invention in that there is an aqueo fluid supply passageway to a below the ground distributi location, and at least one passageway extending from

said distribution location said passageway being adapted to distribute aqueous fluid fed therein from the distribution location so as to maintain the fluid in a generally quiescent state and at a head above a soakage surface over 5. any soakage area whereby to minimise in terms of volume of ground and of time soakage ground wet out at field capacity directly below the passageway.

Preferably such an arrangement in ^' order to inhibit root growth into the space above any liquid within the 10. passageway is closed to atmosphere this being then adapted either by reason of the character of the aqueous fluid fed into the passageway or otherwise to hold a gaseous mixture such "as to inhibit such root growth or attraction of roots into the area.

5 _, As previously explained, this could involve a high concentration of carbon dioxide either seperately introduced or by reason of the natural bacterial activity within the fluid especially where this is an effluent from a septic tank situation.

20. According to a further preferred form of this invention, there is proposed apparatus for incorporation as above described beneath the ground especially to assist in the case that the aqueous fluid is sewage effluent, the apparatus being characterised according to this invention

25. by including a cowling being at least substantially of constant cross section throughout its length and generally being in the form of an upturned U-shape that is with the open mouth of the U-shape lowermost and, at spaced intervals along such length of the cowling, barricades

30. extending

between the two oppositely positioned side walls of t cowling, the barricades being discontinuous between t upper inner surface of the cowling and the top of t barrier so as to provide in effect a weir and the lower 5. the edge- of the barrier being such as to assist providing sealing effect with respect to ground onto which it i placed whereby to assist in providing a damming or we effect.

According to a further preferred arrangement, t 10. inlet into at least one of the distribution includes a substantially vertical passageway at or toward lower end of which is the inlet to the passageway the upper roof of which and sides of which ar defined by a cowling having the characteristics a 15. previously described herein and being arranged so that t distribution passageway is closed to atmosphere except b way of the entrance of access.

For a better understanding of the invention it wil now be described with relation to a preferred embodiment i 20. being emphasised that this is a specific description t which the invention is not intended to be limited wit respect to detail.

This preferred embodiment is described with th assistance of drawings in which FIG 1 is a cross sectiona 25. view showing beneath the ground, an arrangement accordin to the preferred embodiment of this invention, FIG 2 is perspective with partly cut away portions of a cowling wit a plurality of spaced apart barricades located therealon as used in the embodiment as shown in FIG 1 and FIG 3 is

30 cross sectional view transverse to that shown in FIG showing in this case typically positioned plants thes being shown very schematically above a distributio passageway incorporating the cowling as shown in FIG 1.

Referring especially to FIG 1, the installation shown below the ground level 1 includes a septic tank facility 2 and in conventional manner a distribution outlet from this shown at 3 and this leads into an arrangement which is

5. incorporated into a generally back filled trench 4.

The arrangement for back filling essentially incorporates the steps of digging a trench and then simply returning to the trench thus dug the soil taken from the trench which however has of course been broken up and

10. caused to become more porous.

The back filled trench is defined generally by the lines-5 and 6.

Within the back filled area then there is provided an inspection conduit 7 which is vertical and extends to a 15. base location 8.

Leaving off from this inspection conduit 7 is a distribution passageway 9 which is shaped and defined by reason of a cowling 10 which includes at spaced intervals therealong barricades 11.

20. --- ^~ one preferred instance which is typical and limiting the length, of the distribution passageway 9 is approximately 8 metres and the height internally of the passageway is 100 millimetres with the height of each weir being 50 millimetres with an approximate width of 100

25. millimetres.

The position of each weir then is such that it has inclination of approximately 45 with respect to t direction of elongation of the cowling 10 so as to promo gentle streamlined flow of any water flowing over ea

5. barricade.

Each barricade 11 is made from plastic and is attach in suitable manner in- the preferred embodiment by a bo and nut shown at 13 to the sides of the cowling 10 whi comprises as is shown especially in FIG 2 and in the oth 10. Figures as a U-shaped member in cross section with location its open mouth lower most so as to provide betwe each barricade a soakage location area which of course directly the contact area for aqueous fluid within t distribution passage 9.

15. The upper end of the distribution passage way 9 shown at 14 and as is shown, this is closed simply by bei covered with earth so that provided there is fluid as shown in FIG 1 at 15 within the lower end of t distribution passage way 9 then this forms a seal a

20. entraps air within the upper end of the distributi passage way 9.

This then describes in simple terms the installati from which it will be seen that the installation is bo very simple to instal and economic in being made fr 25. materials that can be eminently simple and long lasting an underground environment such as described a furthermore as has been described, using

O..IPI

the techniques described, the concept promotes inhibition of significant root growth into the distribution passage way areas .

This can mean of course that the overall size of the 5. installation can be considerably reduced because trees having significant water take up capacity can be planted in the close vicinity of this installation and these will produce a significant take up of the water without of course in dry times tending to enter the distribution areas 10. themselves and thus by reason of die back or otherwise block the distribution channels as such.

.An important factor as to why the installation is effective can be understood by reference to simulated wet out area indications and in FIG 1 there is shown a line 16 15. which indicates what might be termed a field capacity boundary showing a typical saturation boundary limit of soil directly below the passage way 9. _

It will be noticed that this generally proceeds almost directly downward and indeed soakage distribution is

20. achieved more by reason of causing the soakage to distribute out from the side of the area directly below the soakage passage way 9.

OK?I

This is shown especially in FIG 3 in which there is shown a dotted pattern outline showing an expected saturation distribution pattern below and out to the sides of the distribution channel.

5. The point is that as the liquid proceeds to both sides 16 and 17 it will tend to rise to a large extent by capillary action within the soil as it distributes out and accordingly is exposed to free air held within the soil and of course accessible to atmosphere.

10. As this occurs more and more, the liquid takes up more oxygen and of course becomes aerobic and is thereby both useful to the roots of a plant and the roots are not inhibited by the liquid.

-The embodiment can of course also reside in the

15. method of effecting removal of aqueous fluid by soakage into the ground by including the step of introducing such aqueous fluid into apparatus having the characteristics as described in such a way as to close off the passage way from access to atmosphere and by

20. reason of the contents of the aqueous fluid and bacterial action or otherwise such as the introduction externally of retardant gas, have within the closed space above the liquid within the distribution soakage passage way a content of gas such as carbon dioxide of

25. sufficiently high concentration to inhibit growth of roots therein.

The invention can also reside in a cowling to be used in an installatin of the type described having the characteristics as shown namely having an up turned U-shape and 5. having a plurality of weirs spacedly located thereupon.

With respect to the preferred embodiment this is shown in the illustrations as having a rising inclination from the entrance but it can be horizontal 10. or even slightly falling the effect being much the same because of the weirs providing the holding effect.

In FIG 1 of the preferred embodiment in a typical system, the boundary shown at 16

15. is shown where introduction of water over a period of time is less than a full quota typically during a season inwhich this will be the case, and soakage will be very effective and there is shown a second

20. boundary at 17 which will show a typical distribution pattern when the passageway is effectively filled with fluid.

Once again it is shown as a typical steep curve and in practice this seems to be 25. the case at least in this direction whereas to the side because of the greater depth of free water above the soakage surface promotes this distribution.

It will -be obvious that a system such as that described can be used in co¬ operation with conventional installations in which perhaps for large installations a conventional installation can be used as an over flow or back up facility.

It will be further quite apparent that whereas in

10. relation to the specific application, sewage effluent has been used and has some value in relat-ion to the soakage arrangement, the same concepts can be used inrelation to normal water distribution where plants are

15. to be provided with water inthe normal way of irrigation.

At least then in the widest concept, it is not conceived that this invention is limited to merely effluent as the aqueous 20. fluid.

There is however some difficulty with respect to anaerobic character of the liquid but , of course sewage effluent is not the only way of effecting or obtaining an

25. anaerobic character to water.

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