TECHNICAL FIELD
This invention relates to a method of converting organic waste materials including bio-organic and/or wastewater sludges into a soil amendment or fertilizer with a beneficial mix of macro and micro nutrients that can be used on agriculture land requiring an amendment or fertilizer with a neutral pH.
The invention is particularly useful in stabilizing the organic waste so that they can be safely utilized in combination with other micro and macro nutrient additives.
BACKGROUND AND PRIOR ART OF THE INVENTION
Municipal and industrial wastewaters contain significant quantities of phosphorus and nitrogen, and the removal of these nutrients has become an important facet of wastewater treatment.
In a wastewater treatment plant, phosphorus and nitrogen can be removed by both biological and physical chemical means. Biological means of nutrient removal are generally preferred, as they result in lower waste sludge production, produce a sludge that is more amenable to land application, and have the public perception that biological processes are more "environmentally friendly" than chemical processes.
Processes using biological mechanisms for phosphorus and nitrogen removal are generally referred to as biological nutrient removal.
Relevant prior art references for providing a full understanding of the use of bio-organic and wastewater sludges as beneficial soil or fertilizers for agricultural lands and processes for the production of treated sludges include U.S. Pat. Nos. 4,781,842; 4,902,431; 5,275,733; 5,417,861; 5,853,450; 5,853,590; 6,248,148 and 6,407,038; and references contained therein.
Of particular interest is U.S. Pat. Nos. 4,902,431 as it speaks to a process to further reduce pathogens, wherein lime or kiln dust and/or other alkaline materials are mixed with a wastewater organic waste in sufficient quantity to raise the pH of the mixture to 12 and above for at least two hours and drying the resulting mixture by simple aeration over a period of time. The lime or kiln dust and/or other alkaline materials helps create the pathogen reduction reaction but also acts as a desiccant
Of particular interest is also U.S. Pat. No. 5,853,590, which describes a method of treating waste water treatment plant sludge, to provide a stable product for use as a beneficial soil or fertilizer for agricultural lands with a resulting pH in the alkaline range.

This method includes the steps of:
a) mixing sludge with at least one alkaline material in an amount sufficient to raise the pH of the mixture to a level of at least 12 and to increase the percent of solids in the mixture to at least 40% by weight, and such that the odorant sludge organics and inorganics are bound to adsorbent particles of the alkaline material,
b) aerating and drying the mixture by agitation and heating to stabilize the mixture and increase the percent solids to at least 50% by weight, and
c) pasteurizing the dried mixture at a temperature at or above 52 degree. C by application of heat resulting from an exothermic reaction of the alkaline material with water in the sludge,
wherein step (b) is carried out in a mechanical means, and wherein the heat applied for drying in step (b) reduces the amount of additional heat required for pasteurization in step (c) thereby reducing the amount of alkaline material needed for the exothermic reaction in step (a).
It is widely known that the step (b) is required in order to get a final product that has an acceptable final water content of no more than 50%. It is also widely known that the water content of 25% or less is preferred for a final product that is distributed to the end markets by means of individual soil amendment or fertilizer bags.
Further interest is Canadian Patent No. 2,410,814, which describes an improved process over aforesaid U.S. Patent No. 5,853,590 wherein sufficient time is allowed under step (a) prior to step (b) to enable sufficient slaking of the alkaline material in the mixture to prevent or limit the production of fugitive dust during step (b). This is achieved by providing for further time for reaction of the water in the organic waste material with the alkaline material prior to the aeration and drying step 2.
However, although the manufacturing process described in the aforesaid patents US 5,853,590 and Canadian Patent No. 2,410,814 provides an improvement in the art found in earlier patents, it and all earlier arts suffer from:
a) a drawback of producing a final product that has a pH in the alkaline range and is therefore not a product that can be used effectively in lands or soils that do not need or cannot benefit from an alkaline additive,
b) high fugitive (ammonia being one) odors are produced when macro and micro nutrient additives are added to the mixture to improve the final macro or micro nutrient concentration of the final product,
c) high production costs where mechanical drying is used to reduce the water content of the final product to the acceptable range, and
d) low macro nutrient concentrations in the final product when the mechanical drying portion of the process is replaced by the addition of a desiccant material to reduce the water content of the final product to the acceptable range.
There is therefore a need for an improved process of treating sludge to provide a stable product that does not suffer from the aforesaid disadvantages and can be used on soils that do not or cannot benefit from an alkaline adjusting soil amendment or fertilizer.

OBJECTS OF THE INVENTION
It is an object of the present invention to provide a process of treating sludge that:
a) eliminates the mechanical drying step, so as to lower final product costs,
b) lowers the pH of the final product so that the final product has a neutral pH or only slightly alkaline, and
c) minimizes the negative impact on final product odors and textures resulting from the addition of macro and micro nutrient containing additives to increase the macro and micro nutrient concentration of the final product.
It is yet another object of the present innovation to provide a stable, pathogen free beneficial product that can be produced using a mobile production facility or a permanent production facility.
SUMMARY OF THE INVENTION
According to the present invention, there is provided an improved process for the conversion of organic waste material into a stable, pathogen free, neutral or moderately alkaline product for use as a beneficial soil amendment or fertilizer for agricultural lands.
According to another aspect, the invention also allows for the final product to have improved macro and micro nutrient concentrations.
According to a further aspect of the invention, the mechanical drying step can be eliminated by mixing in a material that has both acidic and desiccant properties, such that:
1. the desired chemical and physical product qualities needed for the final product are achieved,
2. the macro and micro nutrient content of the final product is achieved resulting in the final mixed material having more beneficial agricultural uses and,
3. the release of noxious fugitive odors during the production process is better managed especially where the final mixed material is placed in bags for shipment.
According to yet a further aspect of the invention, the process will produce a final end product is at least no more than 25% water by wet weight and is a stable, pathogen free, neutral or moderately alkaline product that can be used as a beneficial soil amendment or fertilizer for agricultural lands.

DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to an improved process for the conversion of organic waste material into a stable, pathogen free, neutral or moderately alkaline product for use as a beneficial soil amendment or fertilizer for agricultural lands.
The present invention particularly relates to the final product to have improved macro and micro nutrient concentrations.
This invention also relates to a process that will produce a final end product is at least no more than 25% water by wet weight and is a stable, pathogen free, neutral or moderately alkaline product that can be used as a beneficial soil amendment or fertilizer for agricultural lands.
The present innovation qualifies as a pathogen reduction method in Part 503 of the USA Environmental Protection Association Environmental Regulations and Technology -Control of Pathogens and Vector Attraction is Sewage Sludge.
Further, the product is qualified as EQS by meeting Table 3 pollutant limits in Part 503 of the USA Environmental Protection Association Environmental Regulations and Technology - Control of Pathogens and Vector Attraction is Sewage Sludge.
Surprisingly, the inventors have discovered that the mechanical drying step in the current teachings can be eliminated by mixing in a material that has both acidic and desiccant properties, such that:
1. the desired chemical and physical product qualities needed for the final product are achieved,
2. the macro and micro nutrient content of the final product is achieved resulting in the final mixed material having more beneficial agricultural uses and,
3. the release of noxious fugitive odors during the production process is better managed especially where the final mixed material is placed in bags for shipment.
Accordingly, the invention provides an improved process for the conversion of organic waste material into a stable, pathogen free, neutral or moderately alkaline product for use as a beneficial soil amendment or fertilizer for agricultural lands.
The invention also allows for the final product to have improved macro and micro nutrient concentrations.
The invention provides an improved process which includes the steps of
(a) mixing the organic waste material with a highly reactive alkaline material and a desiccant material in an amount sufficient to:
a. raise the solids content of the mixed material to at least 60% W/W;
b. raise the pH to at least 8
c. let the mixed material rest for 24 hours;

(b) mixing the product resulting from (a) above with:
a. a further desiccant that contains some beneficial macro or micro
nutrients, and
b. other materials that are not necessarily desiccants, but contain
beneficial macro and micro nutrients.
The process will produce a final end product is at least no more than 25% water by wet weight and is a stable, pathogen free, neutral or moderately alkaline product that can be used as a beneficial soil amendment or fertilizer for agricultural lands.
Preferably, step (a) comprises pasteurizing the resulting mixed material such that the pathogens resident in the organic material are killed.
Essential goals achieved through step (a) are:
1. destruction of the pathogens in the waste organic material by raising the pH and ambient temperature of the mixed material,
2. raising the solids levels of the mixed material such that, when that mixed material is then mixed again with further desiccants, the resulting final product is such that it allows for the ease of application to agricultural lands, and
3. enhancing the macro and micro nutrient concentration of the final
product.
Essential goals achieved through the addition of other additives in step (b) are:
1. increase in the macro and micro nutrient concentrations in the final product,
2. lowering of the pH value of the final mixed product, and
3. raising the solids levels of the product to allow for ease of application to agricultural lands.
Surprisingly, the inventors have found that for step (a), the addition of a low-reactivity material, e.g. cement-kiln dust, lime-kiln dust and/or flyash, or other similar materials whose main purpose is to bulk up the solids of the mixture, along with a high-reactivity material, e.g. quicklime or slaked lime, whose main purpose is to raise the temperature and pH of the mixture in certain combinations meets the goals described above without the pH having to be raised to the 12 range as taught in prior art applications.
By judicial selection of the amount of the high-reactivity material in conjunction with a suitable amount of the low-reactivity material, the desired goals of the present invention are achieved.
The term "low reactivity" means low efficacy with respect to temperature and pH increases in both time and value while "high reactivity" means high efficacy with respect to temperature and pH increases in both time and value.

Preferably, the ratio of the low reactive alkaline material to the high reactive alkaline material is selected from the range 10:1 to 8:1 by volume, more preferably from 10:1.
Dosage of the low reactive materials will vary depending on the water content of,the waste organic material. The higher the water content of the waste organic material, the higher the low reactive alkaline material dosage and visa versa. Preferably, the combined water content of the mixed material resulting from step (a) is no more than 30% by wet weight.
The amount of the low-reactive material (fly ash for instance) required in step (a) is advantageously increased over the amount of use in prior art applications.
Of particular benefit in the practice of the invention is that the mixed material resulting from step (a) can be further improved:
1. by lowering the pH of the material to more of a neutral or slightly alkaline level, and
2. increasing the macro and micro nutrient concentration of the material to improve the final product agronomic value without the production of fugitive produce any noxious odors, or any other negative physical characteristic.
The process according to the invention comprises the steps and apparatus shown in Figure 3 is suited to:
(a) eliminate mechanical drying step (and attendant conveying units), and
(b) to include an additional mechanical mixing process that:
a. adds a further desiccant, and
b. adds needed macro and micro nutrients.
EXAMPLES
Example 1:
The inventive process involves 2 steps:
(a) the organic waste material is mixed using a mechanical continuous mixing
machine (1) with a highly reactive alkaline material and a low reactive
alkaline material in an amount sufficient to:
a. raise the solids content of the mixed material to at least 60% W/W;
and
b. raise the pH to at least 8
c. let the resulting mixed material rest for 24 hours;
(b) the product resulting from (a) above is them mixed using a mechanical
continuous mixing machine (5) with:
a. a further desiccant that contains some beneficial macro or micro nutrients, and

b. other materials that are not necessarily desiccants, but contain beneficial macro and micro nutrients
DESCRIPTION OF THE DRAWING
In order that the invention may be better understood, a preferred embodiment will now be described by way of example only, with reference to the accompanying drawing, wherein:
FIG. 1 is a diagrammatic representation of a process and apparatus, according to the invention.
FIG. 1, shows the present innovation wherein:
(a) the organic waste material(A) is mixed using a mechanical continuous mixing
machine (1) with a highly reactive alkaline material(2) and a low reactive
alkaline material (3) in an amount sufficient to:
a. raise the solids content of the mixed material to at least 60% W/W;
and
b. raise the pH to at least 8
c. let the resulting mixed material rest for 24 hours;
(b) the product(B) resulting from (a) above is them mixed using a mechanical
continuous mixing machine (5) with:
a. a further desiccant (4) that contains some beneficial macro or micro
nutrients, and
b. other materials that are not necessarily desiccants, but contain
beneficial macro and micro nutrients
Diagram Key:
1 & 5 : Mechanical Mixing Process
2: Highly Reactive Alkaline Material
3: Low Reactive Alkaline Material
4: Nutrient Rich Additives
6: Heat Pasteurization
A: Organic Waste Material
B: Final Product
In step (a), the low reactive alkaline material comprising flyash is dispensed from a silo, while high-reactive second alkaline material can be fed into the mixer using a number of mechanical (silo) or manual processes.

In step (b), the further desiccant and the other materials that are not necessarily desiccants, but contain beneficial macro and micro nutrients can be fed into the mixer (5) using a number of mechanical (silo) or manual processes.
Step (a) and Step (b) are physically separated by allowing the mixed material resulting from step (a) rest for a minimum of 24 hours so as to allow the organic waste material to fully mix and settle with both the high reactive and low reactive alkaline material.
Although this disclosure has described and illustrated certain preferred embodiments of the invention, it is to be understood that the invention is not restricted to those particular embodiments. Rather, the invention includes all embodiments which are functional or mechanical equivalence of the specific embodiments and features that have been described and illustrated.
It will be readily apparent to one skilled in the art that varying substitutions and modifications may be made to the invention disclosed herein without departing from the spirit of the invention. Thus, it should be understood that although the present invention has been specifically disclosed by the preferred embodiments and optional features, modification and variation of the concepts herein disclosed may be resorted to by those skilled in the art, and such modifications and variations are considered to be falling within the scope of the invention.
It is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of "including," "comprising," or "having" and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. It must be noted that, as used in this specification and the appended claims, the singular forms "a," "an" and "the" include plural references unless the context clearly dictates otherwise.

CLAIMS
We Claim:
1. A process to convert organic waste materials into a soil amendment or fertilizer
with a beneficial mix of macro and micro nutrients that can be used on agriculture
land, wherein the process includes the steps of:
Step (a):
i. mixing the organic waste material with a highly reactive alkaline
material and a desiccant material in an amount sufficient to: ii. raise the solids content of the mixed material to at least 60% W/W;
and iii. raise the pH to at least 8 iv. let the mixed material rest for 24 hours;
Step (b) mixing the product resulting from (a) above with: v. a further desiccant that contains some beneficial macro or micro
nutrients, and vi. other materials that are not necessarily desiccants, but contain
beneficial macro and micro nutrients.
2. A process as claimed in claim 1, wherein one of the alkaline materials used in step (a) is a low-reactive material that is also a desiccant.
3. A process as claimed in claim 1, wherein one alkaline material is selected from the group consisting of low reactive alkaline materials such as cement-kiln dust, lime-kiln dust and flyash.
4. A process as claimed in claim 1, wherein the second alkaline material used in step (a) is a high-reactive material.
5. A process as claimed in claim 4 wherein the second alkaline material used in step (a) is selected from the group consisting of quicklime and slaked lime.
6. A process as claimed in claim 1, wherein the ratio of the low reactive alkaline material to the high reactive alkaline material is such that the pH does not raise higher than 8 in the mixed material resulting from step (a).
7. A process as claimed in claim 1, wherein the material containing the macro and micro nutrients and used in step (b) does not react with the mixed material from step (a) so as to produce noxious fugitive odours.
8. A process as claimed in claim 1, wherein the material containing the macro and micro nutrients used in step (b) has sufficient acidic properties so as to render the product of step (b) as a pH of neutral or slightly alkaline (no more then pH of 8).

9. A process as claimed in claim 1 wherein the material containing the macro and micro nutrients used in step (b) has water content so as to render the product of step (b) as a product containing no more than 25% water by wet weight.
10. A process as claimed in claim 1, wherein the material containing the macro and micro nutrients used in step (b) does not have the chemical components that will cause further conversion of the nitrogen found in the product of Step (a) and the production of fugitive noxious odours.
11. A process as claimed in claim 1, wherein the waste organic material is selected from the group consisting of any organic waste material including raw primary wastewater sludge, enhanced primary treated sludge, digested wastewater sludge, secondary wastewater sludge, combined wastewater sludge, a product of industrial process that includes microbial cells or components, bioorganic sludges, organic sludges and mixtures thereof.
12. The portable and fixed apparatus for the conversion of organic waste materials into a soil amendment or fertilizer with a beneficial mix of macro and micro nutrients that can be used on agriculture land requiring an amendment or fertilizer with a neutral pH in which the process as claimed in claim 1 is carried out.