Water management system

Abstract

An outdoor water management system including at least one reservoir configured to receive highly concentrated contaminated water, a weather proof cover, covering the reservoir to define at least one chamber and water vapour removal means, configured to remove evaporated water from the at least one chamber wherein the at least one chamber is configured to further concentrate the contaminated water while providing long-term weatherproof storage thereof.

Claims

1. An outdoor water management system comprising: a terminal reservoir configured to receive concentrated contaminated water; a weather proof cover, covering the terminal reservoir to define at least one chamber; and wherein the at least one chamber is configured to further concentrate the contaminated water by removing evaporated water from the at least one chamber while providing long-term weatherproof storage of the further concentrated contaminated water within the chamber.

2. The outdoor water management system of claim 1, comprising a plurality of reservoirs provided in series wherein contaminated water to be treated flows through each reservoir of the plurality of reservoirs to generate the concentrated contaminated water that is received by the terminal reservoir.

3. The outdoor water management system of claim 2 wherein the plurality of reservoirs comprise elongate, lined enhanced evaporation ponds with a depth of up to 100 mm.

4. The outdoor water management system of claim 2 configured to heat the contaminated water.

5. The outdoor water management system of claim 1 wherein the terminal reservoir is provided with a shaped roof with at least one entry to funnel wind across the reservoir or increase wind speed.

6. The outdoor water management system of claim 1 further including at least one nozzle configured to spray the contaminated water to enhance effective evaporating water surface area in the terminal reservoir.

7. The outdoor water management system of claim 2 wherein at least one of the plurality of reservoirs is a salinity gradient solar thermal pond.

8. The outdoor water management system of claim 1 wherein the terminal reservoir is provided with evaporated water vapor removed under a vacuum.

9. The outdoor water management system of claim 8 wherein the evaporated water vapour removed is then condensed.

10. The outdoor water management system of claim 2 wherein sub-surface pond water bubbling or sparging is used in at least one of the plurality of reservoirs.

11. The outdoor water management system of claim 2 wherein at least one of the plurality of reservoirs provided in series is shaped such that contaminated water drains to a low point for transfer to of the plurality of reservoirs provided in series.

12. The outdoor water management system of claim 2 wherein the reservoirs are elongate.

13. The outdoor water management system of claim 2 wherein the reservoirs are lined using high density polyethylene sheeting.

14. The outdoor water management system of claim 2 wherein the contaminated water enters each reservoir under gravity.

15. The outdoor water management system of claim 1, further comprising a pump to pump the contaminated water through the system.

16. The outdoor water management system of claim 15 wherein the pump is configured to pump water at a rate to add turbulence to the water in the reservoir and enhance evaporation.

17. The outdoor water management system of claim 1 further comprising an agitator, configured to agitate the contaminated water in the terminal reservoir.

18. The outdoor water management system of claim 1 wherein the contaminated water is heated within the terminal reservoir.

19. The outdoor water management system of claim 1 further including a salinity gradient solar pond to receive contaminated water to accelerate evaporation wherein the terminal reservoir is configured to receive hypersaline contaminated water from the salinity gradient solar pond and further evaporate it to a crystalline salt.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) Various embodiments of the invention will be described with reference to the following drawings, in which:

(2) FIG. 1 illustrates a water treatment system, according to an embodiment of the present invention for treatment of salinized and mineralised wastewater.

(3) FIG. 2 illustrates a cross sectional view of an evaporation pond of the water treatment system of FIG. 1;

(4) FIG. 3 illustrates a cross sectional view of the terminal storage pond of the water treatment system of FIG. 1 which contains crystalline salt;

(5) FIG. 4 illustrates a cross sectional view of a saline gradient solar pond (SGSP) of the water treatment system;

(6) FIG. 5 is a schematic illustration of the operation of enhanced evaporation with condensation in a pond of a preferred embodiment with a fixed roof.

(7) FIG. 6 is a schematic illustration of the operation of enhanced evaporation with condensation in a pond of a preferred embodiment with a retractable/expandable roof.

(8) FIG. 7 is a schematic illustration of the operation of a system of a preferred embodiment on moderately sloping ground with a number of ponds in series.

(9) Preferred features, embodiments and variations of the invention may be discerned from the following Detailed Description which provides sufficient information for those skilled in the art to perform the invention. The Detailed Description is not to be regarded as limiting the scope of the preceding Summary of the Invention in any way.

DESCRIPTION OF EMBODIMENTS

(10) FIG. 1 illustrates a water treatment system 100, according to an embodiment of the present invention. The water treatment system 100 is particularly suited to concentrating salts (salinized and mineralised wastes) from water, but may also be used to separate other dissolved and suspended solids from water.

(11) As described in further detail below, the system 100 utilises and array of enclosed evaporation ponds, which are configured to enhance evaporation using sprinklers and heating, and from which vapour is condensed to water for beneficial use. The resultant waste concentrate is then safely stored nearby in a storage and evaporation pond where it is easily retrieved as needed

(12) The system 100 is described with reference treatment of water from a high natural groundwater salinity/mine tailings dam or from a reverse osmosis, forward osmosis, membrane distillation, thermal distillation, ion exchange or other primary water treatment desalination system used individually or in some combination

(13) These dams usually contain water with salinities ranging from about 2000 to 60000 mg/L Total Dissolved Solids (TDS). In other embodiments, brine from membrane distillation units having up to about up to about 200,000 mg/L TDS may be treated. The skilled addressee will, however, readily appreciate that any suitable brine, mineralised or otherwise contaminated water may be treated.

(14) Initially, salinized/mineralised wastes from the “brine” dam 105 is pre-processed in a pre-processing module 110. The pre-processing may comprise heating of the brine, the addition of chemicals or additives to the brine, or removal of suspended solids (SS) or turbidity or specific toxic or other chemistries pre accelerated evaporation. Brine heating under pre-processing in 100 can be from SGSP, transfer of water using a plurality of small pipes versus one large pipe and parabolic mirror super-heated salts.

(15) The pre-processed brine is then provided to a plurality of evaporation ponds 115 which rapidly evaporate and concentrate the brine into a hypersaline state and to recover the evaporated water for beneficial use. The evaporation ponds 115 are coupled to the pre-processing module 110 in parallel by a plurality of pipes 120, which are also configured to primarily pre-heat the brine, remove any specific problem micro-chemistry and possibly filter additional SS. In particular, the pipes 120 are advantageously dark in colour, and thus configured to be heated by the sun, and may extend across a UV attractive material.

(16) Furthermore, the pipes 120 may be associated with a parabolic solar mirror, or other heater, to heat the water in transit to accelerated evaporation. Similarly, the pipes 120 may comprise 13-19 mm polyethylene pipes which travel large distances on HDPE sheeting or on beds of fine basalt aggregate or granular alumina to augment the heating of pipes 120 and thus the water therein.

(17) The evaporation ponds 115 are long and narrow, and may be up to 125 m long. The ponds 115 are configured to operate best when the brine (or waste water) is at a depth of up to about 100 mm, as this increases direct solar heating efficiency, and may heat the water by about 6-15° C. during the day, depending on season. In any event, the ponds 115 are capable of containing brine at a depth of about 1.5-2 m if needed.

(18) Conduit 150 or a waste removal system is provided to remove the waste products from evaporation ponds 115 to the

(19) As best illustrated in FIG. 2, the evaporation ponds 115 comprise a reservoir 205, in which contaminated water 210 is held, and a weather proof cover 215, covering the reservoir 205 to define a chamber.

(20) Floating sprinklers 220 (individual or in latticed formation) are provided on the contaminated water 210 and is configured to spray water in the chamber from a plurality of nozzles. The sprinklers 220 are low pressure, low trajectory, uniform droplet sprinklers. The cover 215 prevents the sprayed water from leaving the chamber and contaminating the environment, regardless of environmental considerations such as wind.

(21) The cover 215 is formed of UV stabilised, transparent plastic, which is about 1.5 mm thick and is supported by a frame. The cover 215 is retractable, to provide evaporating wind and human access to the reservoir 205.

(22) The cover 215 defines an arched roof over the reservoir 205, and includes vapour outlets 225 near an apex of the arched roof. As illustrated in FIG. 1, the vapour outlet 225 is coupled to a condenser 125 for condensing water from the vapour. The condensed water is then stored in a tank 130, for later use.

(23) The vapour outlets 225 are located periodically along a length of the cover 215, and the condensate may be removed from the outlets 225 through a negative pressure differential. This may be achieved by providing below atmospheric pressure at the condenser 125. The use of the cover 215 and low pressure outlets 225 leading to the condenser 125 increases evaporation rates in the reservoir 205.

(24) The extracted vapour may be beneficially used in households or the community more generally. As such, embodiments of the present invention are particularly useful in areas adjacent to sea water or other bodies of currently unused saline/mineralised waters. As an illustrative example, the condensed water may be used as potable water, for irrigation, for domestic consumption or for blending with waste water to lower salinity sufficiently for irrigation of salinity tolerant crops on suitable soils.

(25) The cover 215 also includes heating inlets 230, through which heated water air and, optionally, heated water can be provided if this augments rates of accelerated evaporation (both pipeline systems being insulated). As illustrated in FIG. 1, the heating inlets 230 are coupled to a heater 135 from which the heated air (via a radiator) or directly pumped heated water is provided. The heater 135 may comprise a heat sink and heat transfer means, as outlined below.

(26) The reservoir 205 may be formed in the ground by a grader and/or or scraper. The grader or scraper may be laser guided, which provides an accurate even depth. The reservoir 205 is high-density polyethylene (HDPE) lined, which prevents the contaminated water 210 from leeching into the environment.

(27) The reservoir 205 includes a planar base 205a, from which sidewalls 205b upwardly and outwardly extend. The reservoir 205 may be graded such that it slopes slightly towards one end. As higher salinity water naturally sinks to the floor underlying fresher water, the sloped base 205a allows hypersaline water to naturally move to a low point from which it can pumped (or fed by gravity) to other evaporation ponds 115 or a storage pond.

(28) The evaporation ponds 115 are illustrated as being coupled in parallel in FIG. 1. However, in alternative embodiments, the evaporation ponds 115 may be coupled in series (such that the waste water is progressively concentrated), or in a combination of series and parallel.

(29) The evaporation ponds 115 are coupled to a storage pond 140 which is configured to receive the hypersaline waste water from the evaporation ponds 115, and further evaporate it in a structure capable of providing long-term, weatherproof, sealed storage of the concentrate. The storage pond 140 may also be used for short or medium-term storage prior to commercial use, if desired.

(30) As best illustrated in FIG. 3, the storage pond 140 comprise a reservoir 305, in which the highly concentrated contaminated water 310 is held, and a weather proof cover 315, covering the reservoir 305 to define a chamber, much like the evaporation ponds 115.

(31) A lattice of floating sprinklers 320 is provided on the contaminated water 310 and is configured to spray water in the chamber from a plurality of nozzles. The sprinklers 320 are, similar to the sprinklers 220, and thus low pressure, low trajectory, uniform droplet sprinklers. The cover 315 prevents the sprayed water from leaving the chamber and contaminating the environment, regardless of environmental considerations such as wind, and shelters the contaminated water 310 from the elements.

(32) The cover 315 is, much like the cover 215, formed of UV stabilised, transparent plastic, which is about 1.5 mm thick, is supported by a frame, and is retractable. Similarly, the cover 315 defines a roof over the reservoir 305, and includes vapour outlets 325 located periodically along a length of the cover, near an apex of the arched roof, and are coupled to the condenser 125 for condensing water from the vapour.

(33) The extracted vapour may be mixed with the vapour of the evaporation ponds, or be injected separately into a common condensation process, and may be used beneficially as described above. Similarly, in alternative embodiments, separate condensers may be used for the evaporation ponds and storage ponds.

(34) The storage pond 140 may include one or more agitators 330, along a base 305a of the reservoir 305, to agitate the contaminated water 310. This is particularly useful in breaking crystals and crusts that may form on the contaminated water 310, and can further enhance evaporation.

(35) The agitators 330 may be configured to operate continuously or periodically, and at a variable or fixed rate. The agitators 330 may be mechanical, utilise an inlet of the storage pond 140 (e.g. that contaminated water is sprayed in at high pressure to agitate the other water therein), or agitate the water/crystals/slurry by any suitable means.

(36) The storage pond 140 includes welded HDPE sheet which lines bunds 335 and the floor of the pond as one continuous sheet that extends along a length of the reservoir, and above ground level 340. The bunds 335 ensure that the contaminated water does not leak from the pond 140, and provides increased storage. The bunds may be formed of compacted soil.

(37) The reservoir 305 may be formed in the ground by a laser guided grader or scraper, as outlined above, and be HDPE lined, or more preferably double lined, which protects (as required by best practice and environmental regulation) from the contaminated water 310 leaching into the environment. The reservoir 305 may be formed above ground with suitable insulated materials to restrict heat loss.

(38) The reservoir 305 includes a planar base 305a, from which sidewalls 305b upwardly and outwardly extend. The reservoir 305 is about 1.5 m deep (i.e. the base 305a is about 1.5 m below ground), 2.5-4 m wide at the base 305a with 1:1 grade (45 degree) walls 305b extending upwardly and outwardly therefrom. The bunds 335 are advantageously about 1.5 m high (i.e. 1.5 m above ground). The entire pond 140 (including bund) is thus about 8.5-10 m wide at an upper edge, and about 3 m deep.

(39) The length of the pond 140 is variable depending on the waste water feed rate, the waste chemistry, the rate of evaporation to dry solid and harvesting requirements, but is typically in the order of about 50 m. These ponds can be increased in number as the demand to safely store crystalline salt increases.

(40) The contaminated water is held in the pond as long as desired, and the resulting highly saline solution and/or crystals (or solids) may be extracted when needed for external beneficial use using a solids removal model 145. The solids removal module 145 may be mechanical, comprise a pump, or utilise any suitable process for the removal of highly saline water and/or crystals, including a sludge or slurry thereof. Most highly saline water in 145 will be recycled to the basal layer of the SGSP via a suitable pump.

(41) In the case of high sodium salts, such product may have high value in the chemical industry, and crystalline salt may be used in stockfeed or fertiliser/soil amendment markets. Hypersaline or crystalline salts may be potentially combined with other wastes to make building products or other commercial materials. Alternatively, the salts or crystals may be permanently (or semi-permanently) encapsulated.

(42) The system and components described above is preferably driven by renewal energy, and even more preferably solar and wind driven. In the event of commercialisation of electrical potential energy differences between the EZ zones and bulk water of water storages this energy may be extracted via suitable electrodes for additional system power. As such, the system can be installed adjacent to a mine tailings dam, or other suitable contaminated water source, without needing to be coupled to a power network.

(43) In a preferred embodiments, solar panels or heliostats are associated with, and thus power pumping, heat exchange, operational and environmental monitoring, condensation and saline/mineralised product export components of the system. This reduces the amount of electrical cabling required, and increases redundancy in the system. As an illustrative example, the floating sprinklers described above may be associated with floating solar panel, which avoids the need for cabling to other components.

(44) In the case of solar or wind power, the system preferably also includes batteries and inverters, for the storage of energy therefrom for the reliable supply of constant energy for 240/415 V pumps, compressors requiring constant power input. This enables the system to operate when it is dark or not windy. In the case of expandable/retractable roofs which may be closed and opened on average two times per day in overcast/low to high rainfall conditions requiring up to a 3 KW power supply for 3 minutes per roof movement. These short duration actions would be more cost-effectively executed by a network of one or more small diesel generators which are switched on and off remotely by the cloud based information system driven critical environmental triggers involving acceptable/unacceptable relative humidity, incident solar radiation and barometric pressure indicators from the site weather station. Solar panel/battery/inverter systems for such discontinuous power demand is not recommended. Solar panel/direct 12 volt pumping from saline waste water source to brine pond would be suitable up to 20 m head and 20,000 L/day applications for small projects. For larger projects solar panel/battery/inverter powered pumping systems are preferred.

(45) According to certain embodiments, the system is controlled by an intelligent controller. The controller may choose when to feed water into the evaporation and/or storage ponds, and when to operate tightly controlled above water body aerosol production to enhance effective evaporation surface area condenser or opening and closing of rainfall exclusion roofs. The controller may choose at what rate waste water can be continuously fed during the day to maintain a constant evaporation volume, either under gravity or low pressure pumping from header tank to LEPs via numerous 13 mm PE tubes on an insulated HDPE narrow strip base or recharged daily to a prescribed average depth. Similarly, the jets producing accurate size droplets/aerosols may continue to operate while still efficient (i.e. water is evaporating), or operate at certain times of day. The controller would send alerts to the site operator and other designated recipients when abnormal system behaviour was detected eg. changed flow rates indicating a leakage or changed current flow or operating temperature of water and vacuum pumps, compressors, extractor fans and electric motors which expand and retract rain exclusion roofing.

(46) In some embodiments, the heater 135 comprises a plurality of 13 mm polyethylene pipes on or embedded in a high heat retention medium and/or a saline gradient solar pond or thermal energy sink potentially augmented by a parabolic mirror water heating system.

(47) FIG. 4 illustrates a high saline heating pond 400, according to an embodiment of the present invention. The high SGSP pond 400, receives hypersaline brine from the evaporation ponds 115 or crystalline salt from elsewhere, and uses solar energy to heat entrained saline water up to 100° C. The heated brine water is then a) circulated through insulated piping to and from long, narrow, shallow evaporation ponds (LEPs) to exchange such heat with evaporating water via uninsulated pipework accelerated evaporation via an uninsulated pipe and as well as to b) heat air chamber wind if this augments evaporation through an efficient chamber air temperature management above the total pond evaporating water surface. The same heated air, heated water and compressed air bubbling management system (when entrained salinities exceed 40,000 mg/l TDS) FIG. 1, pond 140, can be used to accelerate the production of marketable crystalline salt from hypersaline solutions, or more specifically in storage pond 140 or pond 300.

(48) In particular, the SGSP is lined with a HDPE liner 405, to define a chamber for receiving the hypersaline water 410. As solar energy falls on the heating pond 400, it heats the water adjacent to the bottom of the pond (1 m depth normally). When water at the bottom of the pool is heated, it does not mix readily with the lower salinity water above it in the Non-Convective Zone (NCV). As such, layers are formed, where the high-salinity lower layer is heated up to 80° C. normally, peaking at about 100° C. and annually averaging 65° C., while the low-salinity water above it is much cooler (e.g. about 50° C.). This hot, salty water can then be pumped from the bottom of the pond 400 using a conduit 415 as a source of thermal energy for use in heated water returning to shallow evaporating water pond 200 or via insulated polyethylene or polypropylene pipes exchanging heat in 400 NCZ and LCZs and then releasing such heat in pond 200 volumes as part of a continuous cycle.

(49) An insulated layer 420 is provided surrounding HDPE liner 405 (or between the double liners), to prevent heat transfer to the earth.

(50) In some embodiments, there may be no need for condensed water. In such case the vapour may be released to atmosphere.

(51) In an alternative embodiment of the present invention, the storage ponds 140 may be provided with reduced evaporation pond 115 capacity prior to hypersaline water entering 140 for production of crystalline waste salt. This is particularly useful when ion exchange (IX), reverse osmosis (RO), or IX/RO or thermal distillation or multi-effects distillation or membrane distillation is used to provide primary water desalination treatment producing a brine waste water stream.

(52) While the above description has focused on saline water, in other embodiments the system may be modified to suit biological waste, such as animal and human waste. In such case, the waste may be mechanically pressed to produce a semi-solid material having a water content of about 20-30% and an eluate.

(53) The resulting eluate may be concentrated, as describe above, to provide a concentrated nutrient rich liquid fertiliser. The remaining solid/semi-dry matter can then be dried in evaporation ponds, similar to the ponds 115 describe above, but without sprinklers. Instead, rollers may be used to ted the matter to increase evaporation.

(54) Once the solid matter is below about 10-15% in water content, it may be raked sideways in the pond where it can be baled into small or large square bales.

(55) Similarly, high sugar or high protein waste food products may be diced and then mechanically pressed to generate fluid and solid/semi-dry matter, which is processed in a similar manner to the biological waste described above. The concentrated eluate (fluid) from this process is particularly valuable as a livestock stockfeed supplement. High sugar carrot tops are particularly suitable for this process, but any high sugar or high protein waste food products may be used.

(56) This systems and methods described above are particularly relevant in managing salinized and mineralised waste waters in agriculture and horticulture, mining, gas, petroleum production sectors, as well as in municipal and rural water supply. While specific embodiments are described, the systems and methods are able to be easily adapted to suit the needs of other sectors, such as the human, animal, agro-processing waste sectors in reducing waste management costs, enhancing the recycling of nutrients for food production and in some cases for converting food industry wastes to valuable stock feeds.

(57) Embodiments of the invention may accelerate the evaporation of waste water following primary desalination treatment of moderately to highly saline groundwater by other technologies referred to in [0106], and provide safe, low cost, accessible storage of derived inorganic, metallic and non-metallic salts. This also enables subsequent commercialisation of such salts where a market exists.

(58) The recovery of vapour from vacuum applied to the clear plastic roofing enhances evaporation, and excludes rainfall from diluting the waste waters and provides the resource to condense and produce a pure water condensate/distillate for beneficial use.

(59) Embodiments of the invention described above are low cost (eg up to $4000/ML for recovering evaporation condensate for beneficial use and for storing crystalline waste salt in the system temporarily (where a commercial market exists) or permanently where no market exists. Where a commercial market exists for waste salt and including the re-processing of valuable entrained minerals, this can significantly reduce the net cost of the total process per ML of waste water treated. The process is totally, sustainable in being able to completely remove contaminants from water and safely store such wastes in perpetuity, if necessary. The closest commercial enhanced evaporation competitors to the fully optioned process with potential condensate/distillate for beneficial use are solar powered multi-effects distillation, new emerging commercial membrane distillation processes or reverse osmosis, forward osmosis or thermal distillation processes all with supporting high energy crystallisers costing in the region of $20000 to $30000/ML of treated waste water.

(60) The commercialisation of the above described embodiments may significantly benefit the economic viability of coal seam gas, coal, and other mining industries as well as high value agriculture and horticulture and regional municipalities constrained by current lack of affordable treatment of saline surface waters or saline groundwaters, which otherwise have high processing costs associated with the salinised/mineralised waste water produced. Furthermore, as embodiments of the present invention provide long term storage of such waste, whereby the environmental risks associated with developments in the renewable and non-renewable resources sector is greatly reduced. This can include systems where non-compliant mines have been abandoned but are now able to rehabilitated and re-activated as waste management is now affordable.

(61) Where groundwater is too saline to grow high value crops, the groundwater may be processed using the above described methods and systems to generate condensate/low salinity water, which can be used to dilute saline groundwater to a level suitable to specific crops. Furthermore, the sale of any salts associated with this process may offset part of the cost associated with operating or installing such systems. In such case, the use of such systems may improve the soil quality over time through removal of salt therein.

(62) In the present specification and claims (if any), the word ‘comprising’ and its derivatives including ‘comprises’ and ‘comprise’ include each of the stated integers but does not exclude the inclusion of one or more further integers.

(63) Reference throughout this specification to ‘one embodiment’ or ‘an embodiment’ means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearance of the phrases ‘in one embodiment’ or ‘in an embodiment’ in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more combinations.

(64) In compliance with the statute, the invention has been described in language more or less specific to structural or methodical features. It is to be understood that the invention is not limited to specific features shown or described since the means herein described comprises preferred forms of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims (if any) appropriately interpreted by those skilled in the art.