NL2018100B1 - A method of reducing the chemical oxygen demand of water obtained by reverse osmosis - Google Patents

A method of reducing the chemical oxygen demand of water obtained by reverse osmosis Download PDF

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Publication number
NL2018100B1
NL2018100B1 NL2018100A NL2018100A NL2018100B1 NL 2018100 B1 NL2018100 B1 NL 2018100B1 NL 2018100 A NL2018100 A NL 2018100A NL 2018100 A NL2018100 A NL 2018100A NL 2018100 B1 NL2018100 B1 NL 2018100B1
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NL
Netherlands
Prior art keywords
permeate
reverse osmosis
water
sulfur compound
spraying
Prior art date
Application number
NL2018100A
Other languages
Dutch (nl)
Inventor
Willems Henk
Original Assignee
Vp Systems B V
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Vp Systems B V filed Critical Vp Systems B V
Priority to NL2018100A priority Critical patent/NL2018100B1/en
Priority to PCT/NL2017/050883 priority patent/WO2018124881A1/en
Application granted granted Critical
Publication of NL2018100B1 publication Critical patent/NL2018100B1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/02—Reverse osmosis; Hyperfiltration ; Nanofiltration
    • B01D61/025—Reverse osmosis; Hyperfiltration
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/58—Multistep processes
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F9/00—Multistage treatment of water, waste water or sewage
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/20—Treatment of water, waste water, or sewage by degassing, i.e. liberation of dissolved gases
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/42—Treatment of water, waste water, or sewage by ion-exchange
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
    • C02F1/441—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by reverse osmosis
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/68—Treatment of water, waste water, or sewage by addition of specified substances, e.g. trace elements, for ameliorating potable water
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F11/00—Treatment of sludge; Devices therefor
    • C02F11/12—Treatment of sludge; Devices therefor by de-watering, drying or thickening
    • C02F11/121—Treatment of sludge; Devices therefor by de-watering, drying or thickening by mechanical de-watering
    • C02F11/123—Treatment of sludge; Devices therefor by de-watering, drying or thickening by mechanical de-watering using belt or band filters
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/42—Treatment of water, waste water, or sewage by ion-exchange
    • C02F2001/425—Treatment of water, waste water, or sewage by ion-exchange using cation exchangers
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/10—Inorganic compounds
    • C02F2101/101—Sulfur compounds
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/10—Inorganic compounds
    • C02F2101/16—Nitrogen compounds, e.g. ammonia
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/30—Organic compounds
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
    • C02F2103/20—Nature of the water, waste water, sewage or sludge to be treated from animal husbandry
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2301/00—General aspects of water treatment
    • C02F2301/08—Multistage treatments, e.g. repetition of the same process step under different conditions

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Water Supply & Treatment (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Nanotechnology (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Hydrology & Water Resources (AREA)
  • Environmental & Geological Engineering (AREA)
  • Organic Chemistry (AREA)
  • Separation Using Semi-Permeable Membranes (AREA)
  • Treatment Of Water By Ion Exchange (AREA)

Abstract

A method of reducing the chemical oxygen demand of water obtained by reverse osmosis, said method comprising the steps of - subjecting water containing a sulphur compound to reverse osmosis resulting in a permeate comprising at least some of the sulphur compound, and - subjecting the permeate to a further purification step. To reduce the problem of the formation of a precipitate that increases cost for maintenance, permeate having - a pH of 3.0 to 6.5, and - a conductivity of less than 75 μSiemens/cm; is subjected to spraying in air.

Description

Octrooicentrum
Nederland
Θ 2018100 © BI OCTROOI (21) Aanvraagnummer: 2018100 © Aanvraag ingediend: 30/12/2016 (51) Int. CL:
C02F 1/44 (2017.01) C02F 1/42 (2017.01) C02F 1/20 (2017.01)
Aanvraag ingeschreven: (73) Octrooihouder(s):
23/07/2018 VP-SYSTEMS B.V. te America.
(43) Aanvraag gepubliceerd:
- (72) Uitvinder(s):
Henk Willems te America.
(Dj Octrooi verleend:
23/07/2018
(74) Gemachtigde:
(45) Octrooischrift uitgegeven: ir. W.J.J.M. Kempes te Hilversum.
25/07/2018
54) A method of reducing the chemical oxygen demand of water obtained by reverse osmosis (Dj A method of reducing the chemical oxygen demand of water obtained by reverse osmosis, said method comprising the steps of
- subjecting water containing a sulphur compound to reverse osmosis resulting in a permeate comprising at least some of the sulphur compound, and
- subjecting the permeate to a further purification step.
To reduce the problem of the formation of a precipitate that increases cost for maintenance, permeate having
- a pH of 3.0 to 6.5, and
- a conductivity of less than 75 pSiemens/cm;
is subjected to spraying in air.
NL Bl 2018100
Dit octrooi is verleend ongeacht het bijgevoegde resultaat van het onderzoek naar de stand van de techniek en schriftelijke opinie. Het octrooischrift komt overeen met de oorspronkelijk ingediende stukken.
A method of reducing the chemical oxygen demand of water obtained by reverse osmosis
The present invention relates to a method of reducing the chemical oxygen demand of water obtained by reverse osmosis, said method comprising the steps of
- subjecting water containing a sulphur compound to reverse osmosis resulting in
- a retentate, and
- a permeate comprising at least some of the sulphur compound; and
- subjecting the permeate to a further purification step.
In the art it is known to process water using reverse osmosis for various reasons. An important field of application is the purification of effluent water before it can be safely discharged. The effluent typically contains organic molecules, for example bio-organic molecules such as proteins, amino acids or degradation products thereof. They may be capable of passing through the reverse osmosis membrane and thus could end up in the environment if the permeate were discharged. However, discharge is problematic because the chemical oxygen demand (COD) of the permeate is too high. Thus it is known in the art to subject the permeate to a further treatment to lower the COD, but achieving the required low COD level adds considerably to the expense. In addition, introducing oxygen into the oxygen-depleted water results into sulphur-containing precipitates causing maintenance problems .
The object of the present invention is to provide a simple and cost-effective method of reducing the chemical oxygen demand of permeate obtained by reverse osmosis.
To this end, a method according to the preamble is characterized in that with the permeate comprising at least some of the sulphur compound having
- a pH of 3.0 to 6.5, and
- a conductivity of less than 75 pSiemens/cm;
the further purification step involves spraying the permeate comprising at least some of the sulphur compound in air.
Without wishing to be bound by any particular theory, it is believed that the presence of the sulphur-comprising compound is the explanation for the difficulty experienced to reduce the chemical oxygen demand to the desired extent. Oxygenating permeate by introducing air according to the state of the art results in an inconvenient sulphur-comprising precipitate. The inventor has found that by spraying in accordance with the method according to the present invention, volatile sulphur compounds, such as H2S, are released from the spray droplets into the atmosphere. This reduces the sulphur concentration to a level where the formation of sulphur-comprising precipitate is reduced. It should be noted that its concentration in air is sufficiently minor to be environmentally acceptable. Also, the quick rise in oxygen concentration may contribute to the prevention of inconvenient precipitate.
In the method according to the present invention, the permeate will typically be subjected to a pre-treatment to adjust at least one of the pH and the conductivity, for example by cation-exchange. It is preferred that ammonium is reduced to a concentration of less than 1 mg/L before spraying the permeate, more preferably to a concentration of less than 0.5 mg/L
The nozzle used for spraying is preferably a so called hollow cone nozzle.
The nozzle used for spraying is preferable a nozzle capable of with a spraying angle of at least 90°. It is possible to spray downward, sideways or upward. Upward spraying can adversely affect the efficient collection of sprayed water, in particular in case of wind.
Typically, the droplets will travel at least 2 meters through the air, preferably at least 3 meters, before they are collected.
Spraying in air is preferably done outdoors.
According to a favourable embodiment, the permeate comprising at least some of the sulphur compound contains ammonium-ions and is subjected to cation-exchange before the step of spraying the permeate.
This allows for the water to contain a reduced amount of ammonium, which has been found to help to reduce the sulphur-related problems .
According to a favourable embodiment, the cation-exchange resin is equilibrated with an acid having a pKa of 2 or less, preferably 1 or less.
Such a cation-exchange material is more efficient at removing ammonia from the liquid.
According to a favourable embodiment, spraying in air involves spraying at a height of at least 4 m above a collection area, the height being preferably at least 6 m.
This has been found to be a cheap and effective way of spraying and of collecting the water after spraying. Nozzles will be preferably be pointing downward to reduce the collection area. The collection area may be a pool.
According to a favourable embodiment, the pH of the permeate comprising at least some of the sulphur compound is between pH of 3.5 to 5.5, preferably between 4 and 5.
It has been found that this promotes the reduction of the sulphur concentration .
According to a favourable embodiment, the permeate comprising at least some of the sulphur compound has a conductivity of less than 35 pSiemens/cm, preferably less than 20 pSiemens/cm, and more preferably less than 15 pSiemens/cm.
It has been found that this promotes the reduction of the sulphur concentration .
According to a favourable embodiment, water comprising material of biological origin is subjected to the reverse osmosis to result in the water containing a sulphur compound.
The biological origin may for example be biological material in effluent from the food industry.
According to a favourable embodiment, the water comprising material of biological origin is derived from excrement from animals.
Treatment of liquid manure or water from solid or semi-solid manure is an important field of application for the present invention, serving as a source of water comprising a sulphur-comprising compound. Typically, for semi-liquid or solid manure, solid material is separated using a filter belt press.
According to a favourable embodiment, at least one cation chosen from calcium and magnesium is added.
This allows for discharge of the purified water into the environment. It has been found that when the purified water is discharged into water of a river or creek, the presence of the cation prevents the formation of a haze (precipitate) caused by the high level of dissolved oxygen present in the purified water according to the present invention. Preferably both cations are added.
According to a favourable embodiment, the purified water is remineralised by passing the purified water over rock material, preferably dolomite.
Thus the remineralisation is performed at very low cost and without any complicated means for process control necessary. Dolomite has been found to be well suited. The rock material comprises for example pieces of rock, which may be present in the collection area. Alternatively, the rock material may be present in a tank into which water from the collection area is passed.
The present invention will now be illustrated with reference to the drawing where
Fig. 1 depicts a flow diagram of an embodiment of the method according to the present invention.
Fig. 1 shows a flow diagram of an embodiment of the method according to the present invention.
To reduce allow discharge of water obtained from liquid pig manure onto the surface water, the method involves the following steps
I) Reverse osmosis with a first reverse osmosis unit 110 essentially as disclosed in NL2007041. It comprises a first reverse osmosis membrane ill that is a 99% salt rejection membrane.
II) Reverse osmosis of the permeate of step I) with a second reverse osmosis unit 120. It comprises a second reverse osmosis membrane 121 that is a 99% salt rejection membrane. The retentate was passed back to the first reverse osmosis unit 110 of step I).
III) Reverse osmosis of the permeate of step II) with a third reverse osmosis unit 130. It comprises a third reverse osmosis membrane 131 that is a 99% salt rejection membrane. The retentate was passed back to the second reverse osmosis unit 120 of step II).
IV) Ion-exchange of the permeate of step III) using a cation-exchange unit 140 containing cationic resin, equilibrated with HC1 as a strong acid to remove ammonium.
V) Spraying of the liquid that passed the cation-exchange material of the cation-exchange unit 140 in air using a spray device 150 comprising downwardly facing nozzles on a pole and at a height of 6 meters. The droplet size was smaller than typical rain drops but a fine spray is not desirable because it is taken away with the wind too easily .
VI) Contacting water collected after spraying in step V) in a remineralization unit 160 comprising a tank filled with lumps of dolomite .
Several experiments were performed using the above steps. The results of one of these experiments are given below, demonstrating the 5 reduction in the chemical oxygen demand (COD).

Claims (10)

CONCLUSIESCONCLUSIONS 1. Werkwijze voor het verminderen van de chemische zuurstofbehoefte van water verkregen door omgekeerde osmose, waarbij de genoemde werkwijze de stappen omvat vanA method for reducing the chemical oxygen demand of water obtained by reverse osmosis, said method comprising the steps of - het aan omgekeerde osmose onderwerpen van water dat een zwavel-verbinding bevat resulterend in- subjecting reverse osmosis to water containing a sulfur compound resulting in - een retentaat, en- a retentate, and - een permeaat dat ten minste een deel van de zwavel-verbinding omvat;- a permeate comprising at least a part of the sulfur compound; enand - het onderwerpen van het permeaat aan een verdere zuiveringsstap; met het kenmerk, dat met het permeaat dat ten minste een deel van de zwavel-verbinding omvat met- subjecting the permeate to a further purification step; characterized in that with the permeate comprising at least a portion of the sulfur compound with - een pH van 3,0 tot 6,5, en- a pH of 3.0 to 6.5, and - een geleidbaarheid van minder dan 75 pSiemens/cm;- a conductivity of less than 75 pSiemens / cm; de verdere zuiveringsstap het in lucht sproeien omvat van het permeaat dat ten minste een deel van de zwavel-verbinding omvat.the further purification step comprises spraying in air the permeate comprising at least a portion of the sulfur compound. 2. Werkwijze volgens conclusie 1, waarbij het permeaat dat ten minste een deel van de zwavel-verbinding omvat ammonium-ionen bevat en voorafgaand aan de stap van het sproeien van het permeaat aan kationen-uitwisseling wordt onderworpen.The method of claim 1, wherein the permeate comprising at least a portion of the sulfur compound contains ammonium ions and is cation-exchanged prior to the spraying of the permeate. 3. Werkwijze volgens conclusie 2, waarbij de kationen-uitwisselingshars is geëquilibreerd met een zuur dat een pKa van 2 of minder, bij voorkeur 1 of minder heeft.The method of claim 2, wherein the cation exchange resin is equilibrated with an acid that has a pKa of 2 or less, preferably 1 or less. 4. Werkwijze volgens een der voorgaande conclusies, waarbij het in lucht sproeien, sproeien inhoudt op een hoogte van ten minste 4 m boven een verzamelgebied, waarbij de hoogte bij voorkeur ten minste 6 m is .A method according to any one of the preceding claims, wherein spraying in air involves spraying at a height of at least 4 m above a collection area, the height preferably being at least 6 m. 5. Werkwijze volgens een der voorgaande conclusies, waarbij de pH van het permeaat dat ten minste een deel van de zwavel-verbinding omvat tussen een pH van 3,5 tot 5,5 ligt, bij voorkeur tussen 4 en 5.A method according to any one of the preceding claims, wherein the pH of the permeate comprising at least a part of the sulfur compound is between a pH of 3.5 to 5.5, preferably between 4 and 5. 6. Werkwijze volgens een der voorgaande conclusies, waarbij het permeaat dat ten minste een deel van de zwavel-verbinding omvat een geleidbaarheid heeft van minder dan 35 pSiemens/cm, bij voorkeur minder dan 20 pSiemens/cm, en met meer voorkeur minder dan 15 pSiemens/cm.The method of any one of the preceding claims, wherein the permeate comprising at least a portion of the sulfur compound has a conductivity of less than 35 pSiemens / cm, preferably less than 20 pSiemens / cm, and more preferably less than 15 pSiemens / cm. 7. Werkwijze volgens een der voorgaande conclusies, waarbij water dat materiaal van biologische oorsprong omvat aan de omgekeerde osmose wordt onderworpen en resulteert in het water dat een zwavel-verbinding bevat.A method according to any one of the preceding claims, wherein water comprising material of biological origin is subjected to the reverse osmosis and results in the water containing a sulfur compound. 8. Werkwijze volgens conclusie 7, waarbij het water dat materiaal van biologische oorsprong omvat is afgeleid van de uitwerpselen van dieren.The method of claim 7, wherein the water comprising material of biological origin is derived from the excrements of animals. 9. Werkwijze volgens een der voorgaande conclusies, waarbij ten minste één kation gekozen uit calcium en magnesium wordt toegevoegd.The method of any one of the preceding claims, wherein at least one cation selected from calcium and magnesium is added. 10. Werkwijze volgens conclusie 9, waarbij het gezuiverde water wordt geremineraliseerd door het gezuiverde water over rotsmateriaal te leiden, bij voorkeur dolomiet.The method of claim 9, wherein the purified water is remineralized by passing the purified water over rock material, preferably dolomite. 1/1 o1/1 o τ— σ> LLτ— σ> LL
NL2018100A 2016-12-30 2016-12-30 A method of reducing the chemical oxygen demand of water obtained by reverse osmosis NL2018100B1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
NL2018100A NL2018100B1 (en) 2016-12-30 2016-12-30 A method of reducing the chemical oxygen demand of water obtained by reverse osmosis
PCT/NL2017/050883 WO2018124881A1 (en) 2016-12-30 2017-12-29 A method of reducing the chemical oxygen demand of water obtained by reverse osmosis

Applications Claiming Priority (1)

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NL2018100A NL2018100B1 (en) 2016-12-30 2016-12-30 A method of reducing the chemical oxygen demand of water obtained by reverse osmosis

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Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3547190A (en) * 1968-06-13 1970-12-15 Shell Oil Co Apparatus for treating waste water associated with hydrocarbon production
US4482459A (en) * 1983-04-27 1984-11-13 Newpark Waste Treatment Systems Inc. Continuous process for the reclamation of waste drilling fluids
CA2723092A1 (en) * 2008-05-02 2009-11-05 Kinetico Incorporated Process for re-mineralizing water deficient in magnesium
NL2007041C2 (en) 2011-07-05 2013-01-08 Henk Hendrikus Jacobus Theophilus Willems MEMBRANE DEVICE FOR THICKING A LIQUID FLOW AND ACCORDING DEVICE FOR RECYCLING AGRICULTURAL WASTE.

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