Filtration media, system and method for the removal of phosphorus and coliforms

Abstract

A filtration media, system and method to passively remove phosphorus and coliforms from wastewater streams is provided. The filtration media system allows wastewater to enter via an inlet toward a diffusor, a filtration media and a filtration media support. The filtered wastewater exits through an outlet. In one aspect, the filtration media broadly comprises sand, activated alumina, peat moss or lime, or any combination thereof. In an exemplary embodiment, the dephosphatation media may further comprise about 20-65% filtration grade sand, about 7-14% granular activated alumina, about 25-50% peat moss and about 5-20% dolomitic lime. The filtration media system may be used in a wastewater treatment method to passively remove phosphorus and coliforms from sewage streams. The dephosphatation media system may be used to passively treat domestic, industrial and commercial sewage streams.

Claims

1) A filtration media to passively remove phosphorus and coliforms from wastewater or sewage streams comprising a material selected from the group consisting of sand filtering media, granular activated alumina, peat moss, dolomitic lime and any combination thereof.

2) The filtration media as defined in claim 1, the filtration media comprising: sand filtering media; granular activated alumina; peat moss; and dolomitic lime.

3) The filtration media as defined in claim 2, the filtration media comprising: between 20-65 vol % of sand filtering media: between 7-14 vol % of granular activated alumina; between 25-50 vol % of peat moss; and between 5-20 vol % of dolomitic lime.

4) The filtration media as defined in claim 3, wherein the sand filtering media comprises sand having: an effective diameter (D10) of between about 0.15 and about 1 mm; a uniformity coefficient (Cu) less than or equal to about 6; 3% or less of the particles have a diameter less than 80 μm; and 20% or less of the particles have a diameter greater than 2.5 mm.

5) The filtration media as defined in claim 2 wherein the dolomitic lime comprises a mixture of calcium carbonate and magnesium carbonate having a density of about 17.7±1.8 lb/m.sup.3.

6) The filtration media as defined in claim 2, wherein the granular activated alumina has a particle size of between about 0.6 mm and about 1.5 mm.

7) The filtration media as defined in claim 2, further comprising one or more other filtration material(s) suitable to remove phosphorus and coliforms from wastewater or sewage streams.

8) The filtration media as defined in claim 3, further comprising one or more other filtration material(s) suitable to remove phosphorus and coliforms from wastewater or sewage streams.

9) A filtration media system to passively remove phosphorus and coliforms from wastewater or sewage streams, the filtration media system comprising: a housing or container; an inlet; a filtration media; a filtration media support; and an outlet.

10) The filtration media system as defined in claim 9, wherein the filtration media comprises: sand filtering media; granular activated alumina; peat moss; and dolomitic lime.

11) The filtration media system as defined in claim 9, wherein the filtration media comprises: 20-65 vol % of sand filtering media: 7-14 vol % of granular activated alumina; 25-50 vol % of peat moss; and 5-20 vol % of dolomitic lime.

12) The filtration media system of claim 9, the filtration media further comprising a diffusing mechanism near or at the end of the inlet.

13) The filtration media system as defined in claim 12, wherein the filtration media comprises: sand filtering media; granular activated alumina; peat moss; and dolomitic lime.

14) The filtration media system as defined in claim 12, wherein the filtration media comprises: about 20-65 vol % of sand filtering media: about 7-14 vol % of granular activated alumina; about 25-50 vol % of peat moss; and about 5-20 vol % of dolomitic lime.

15) A method to passively remove phosphorus and coliforms from wastewater or sewage streams comprising: pumping and directing wastewater or sewage streams in the filtration media system as defined in claim 10; allowing the wastewater to infiltrate the filtration media and accumulate at the bottom of the filtration media system; and allowing the filtered water accumulated at the bottom of the filtration media system to exit via the outlet.

16) A method to passively remove phosphorus and coliforms from wastewater or sewage streams comprising: pumping and directing wastewater or sewage streams in the filtration media system as defined in claim 11; allowing the wastewater to infiltrate the filtration media and accumulate at the bottom of the filtration media system; and allowing the filtered water accumulated at the bottom of the filtration media system to exit via the outlet.

17) A method to passively remove phosphorus and coliforms from wastewater or sewage streams comprising: pumping and directing wastewater or sewage streams in the filtration media system as defined in claim 12; allowing the wastewater to infiltrate the filtration media and accumulate at the bottom of the filtration media system; and allowing the filtered water accumulated at the bottom of the filtration media system to exit via the outlet.

18) A method to passively remove phosphorus and coliforms from wastewater or sewage streams comprising: pumping and directing wastewater or sewage streams in the filtration media system as defined in claim 13; allowing the wastewater to infiltrate the filtration media and accumulate at the bottom of the filtration media system; and allowing the filtered water accumulated at the bottom of the filtration media system to exit via the outlet.

19) A method to passively remove phosphorus and coliforms from wastewater or sewage streams comprising: pumping and directing wastewater or sewage streams in the filtration media system as defined in claim 14; allowing the wastewater to infiltrate the filtration media and accumulate at the bottom of the filtration media system; and allowing the filtered water accumulated at the bottom of the filtration media system to exit via the outlet.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The above and other aspects, features and advantages of the invention will become more readily apparent from the following description, reference being made to the accompanying drawings in which:

[0016] FIG. 1 is an illustration of an embodiment of a dephosphatation system and media;

[0017] FIG. 2 is a plot of an exemplary method of dephosphatation showing the phosphorus concentration as a function of the weeks in both inlet and outlet streams;

[0018] FIG. 3 is a plot of the fecal coliforms content in an exemplary method of dephosphatation, the plots presenting the fecal coliforms concentration as a function of the number of weeks of the exemplary method at both inlet and outlet streams; and

[0019] FIG. 4 is an illustration of an embodiment of a dephosphatation system and media shown with exemplary dimensions.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0020] A novel dephosphatation media for phosphorus removal will be described hereinafter. Although the invention is described in terms of specific illustrative embodiments, it is to be understood that the embodiments described herein are by way of example only and that the scope of the invention is not intended to be limited thereby.

[0021] For purposes of the present application, “dephosphatation system” refers to a system that allows phosphorus and coliforms present in the effluent of a wastewater treatment system to be captured for removal purposes. The expressions “dephosphatation media”, “filtration media” and “filtering media” are used interchangeably and generally refer to media used to capture and remove phosphorus and coliforms, in accordance with the present invention.

[0022] Now referring to FIG. 1, an embodiment of a dephosphatation system 100 is shown. The system 100 comprises a housing 105 or container, an inlet 110, such as an entry conduit, a filtration media 130, a filtration media support 140 and an outlet 160. The system 100 may further comprise a diffusing mechanism 120 near or at the end of the inlet 110.

[0023] In a typical embodiment, the wastewater or contaminated liquid may be pumped or otherwise directed to the top of the filtration media via the entry conduit 110. The diffuser 120 is located in the top portion of the housing 105 and is generally adapted to distribute the wastewater evenly on the top surface 115 of the filtration media 130.

[0024] The wastewater then flows in a generally downward direction through the filtration media 130. The filtered water eventually accumulates in the bottom portion 150 of the filtration system 100 after passing through the filtration media support 140. The filtered water that has accumulated at the bottom of the filtration system will exit the system via the outlet conduit 160 when the volume of filtered water in the bottom portion 150 of the filtration system 100 reaches the outlet conduit 160. The filtered water may then be distributed through conduits or pipes or contained and removed.

[0025] The filtration media 130 may comprise filtration media materials selected from the group consisting of sand, activated alumina, peat moss, lime, and any combination thereof. The filtration media may further comprise one or more other media material(s) suitable for removing phosphorus and coliforms originating from wastewater or sewage streams.

[0026] In one exemplary embodiment, the filtration media 130 may comprise: [0027] about 20-65 vol % of a sand filtering media; [0028] about 7-14 vol % of granular activated alumina; [0029] about 25-50 vol %, of peat moss; and [0030] about 5-20 vol % of dolomitic lime comprising a mixture of calcium carbonate and magnesium carbonate.

[0031] In another exemplary embodiment, the sand filtering media has the following characteristics: [0032] an effective diameter (D10) between about 0.15 and about 1 mm; [0033] a uniformity coefficient (Cu) being less than or equal to about 6; [0034] about 3% or less of the particles having a diameter less than about 80 μm; and [0035] about 20% or less of the particles having a diameter greater than about 2.5 mm.

[0036] In yet another embodiment, the dolomitic lime mixture may further have a density of about 17.7±1.8 lb/m.sup.3 with an uncertainty of about 10%.

[0037] The granular activated alumina is generally known in the art to remove fluoride present in wastewater streams. In the present invention, granular activated alumina may be used to remove phosphorus and coliforms from wastewater streams as demonstrated in the present invention. Although the activated alumina is commercially available in different sizes, tests demonstrated that the mesh 14×28, equivalent to a particle size of between about 0.6 and about 1.5 mm, is advantageous for the application of the present invention.

[0038] The following examples are shown as a result of several tests and typical physical and chemical analysis.

Example 1—Activated Alumina Typical Chemical Analysis

[0039] In the present example, typical alumina chemical analyses are shown in Table I.

TABLE-US-00001 TABLE I TYPICAL CHEMICAL ANALYSIS Constituents Weight % Soda as Na.sub.2O 0.4 Iron as Fe.sub.2O3 0.015 Silicon as Si 0.02 Titanium as TiO.sub.2 0.002 Loss on Ignition 5.5-6.0

Example 2—Activated Alumina Typical Physical Properties

[0040] In the second example, typical alumina physical properties are shown in Table II.

TABLE-US-00002 TABLE II TYPICAL PHYSICAL PROPERTIES Bulk Density (g/cm.sup.3) 0.67 Specific Surface Area (m.sup.2/g) 350-380 Pore Volume (cm.sup.3/g) 0.44 Static water adsorption (%) 19-22 At 60% relative humidity and 20° C.

Example 3—Uptake Capacity

[0041] In a third example, the removal uptake capacity of typical contaminants is shown below in Table III The capacity to remove phosphorus is expressed as mg of phosphate, PO.sub.4, per gram of filtration media. The capacity to remove phosphorus reaches values of up to 40 mg/g. The filtration media also removes other contaminants such as arsenic, fluoride, lead, zinc and selenium.

TABLE-US-00003 TABLE III UPTAKE CAPACITY Arsenic (As) 10 mg/g Fluoride (F) 14 mg/g Phosphate (PO.sub.4) 40 mg/g Lead (Pb)  5 mg/g Zinc (Zn) 15 mg/g Selenium (Se) 2.5 mg/g 

Example 4—Dolomitic Lime

[0042] In a fourth example, the composition of typical dolomitic lime expressed as vol % is shown in Table IV.

TABLE-US-00004 TABLE IV MINIMAL ANALYSIS GUARANTEE Calcium (Ca) 29% Magnesium (Mg)  6% Oxyde de calcium (CaO) 41% Oxyde de magnesium (MgO) 10% Calcium carbonate (CaCO.sub.3) 70% Magnesium carbonate (MgCO.sub.3) 20%

Example 5—Phosphorus Removal Results

[0043] Now referring to FIG. 2, a plot of the exemplary results obtained using the system 100 is shown. The plot shows the concentration of phosphorus as a function of the number of weeks of the process at the inlet and outlet areas. FIG. 2 generally shows the performance of the filtration media in removing phosphorus from a wastewater feed stream. As the total phosphorus inlet concentration (expressed as mg of phosphate, PO.sub.4, per volume of solution) increased in the feed stream up to 2.5 mg/L, the phosphorus outlet concentration remained fairly low even after 26 weeks of operation.

Example 6—Fecal Coliform Removal Results

[0044] Now referring to FIG. 3, a plot of the exemplary results obtained using the system 100 is shown. The plot shows the concentration of fecal coliforms as a function of the number of weeks of the process at the inlet and outlet areas. FIG. 3 generally presents performance levels of the filtration media in removing fecal coliforms from a wastewater feed stream at different times during the process. As the concentration of fecal coliforms varied up to 700 CFU/100 mL, the exit concentration remained fairly low during 23 weeks of operation.

Example 7—Filtration Media

[0045] FIG. 4 shows a specific embodiment of the filtration media 130 inside de filtration system 100 in which the filtration media 130 has a diameter ranging from about 45 cm to about 65 cm and a height ranging from about 90 cm to about 130 cm. One of skill in the art will appreciate that the dimensions of the filtration media may be altered in infinite ways without departing from the nature and scope of the invention.

[0046] The methods apparatus and systems of the present invention may be used to treat wastewater streams as well as sewage wastewater streams originating from septic tanks by removing phosphorus and coliforms.

[0047] While illustrative and presently preferred embodiments of the invention have been described in detail hereinabove, it is to be understood that the inventive concepts may be otherwise variously embodied and employed and that the appended claims are intended to be construed to include such variations except insofar as limited by the prior art.