WO2001042171A2

WO2001042171A2 - A method and system for treatment of animal waste

Info

Publication number: WO2001042171A2
Application number: PCT/IL2000/000816
Authority: WO
Inventors: Dov Ingman; Vladymyr Ogenko
Original assignee: I.M.S. Innovative Material Solutions Ltd.
Priority date: 1999-12-07
Filing date: 2000-12-04
Publication date: 2001-06-14
Also published as: AU1729701A; WO2001042171A3; CN1433388A; HUP0203808A2; KR20020076242A; RU2002115636A; EP1248753A2; IL137735A0; PL356744A1; BR0016267A; CA2393492A1

Abstract

A process for treating liquid or semi-solid animal, including human, waste, and controlling malodor associated with same waste. The animal waste is collected into a receptacle, to form a waste pool. Particulate material which forms an interface layer over a top surface of the waste pool is introduced onto the animal waste pool floatable. The interface layer has multiple functions, based on its chemical composition and physical structure, and provides changes in the properties and composition of the upper pool layers and/or its interaction with the overlaying atmosphere. The interface layer is incubated in the waste pool for a time sufficient to yield an effect of either of the functions, while periodically, if necessary, replacing or replenishing the interface layer with new such particles.

Description

A METHOD AND SYSTEM FOR TREATMENT

OF ANIMAL WASTE

FIELD OF THE INVENTION

This invention relates to the field of waste management and particularly

to a method for the treatment of animal manure, including controlling

malodor associated with same waste, to compositions useful for such

treatment as well as to the uses of the products obtained by said

treatment.

BACKGROUND OF THE INVENTION

Animal waster including excreta, food remains, and animal bedding

typically accumulate in a husbandry of commercial animal production.

Such accumulated substances need to be properly managed. Animal

manure, particularly its odor and excessive nutrient concentrations, are a

serious and a growing problem, especially in the field of commercial

animal husbandry. There is a global need for the development and

improvement of waste management and odor control facilities and method

associated with animal husbandry, e.g. in the beef cattle industry, dairy

industry, poultry industry and in swine industry. Manure can be handled as a liquid, a semi-sohd or a sohd. The amount of

bedding and dilution water influences manure characteristics. These

characteristics affect the type of manure management system suitable for

waste treatment. Typically, solid manure is a combination of bedding and

feces. Semi-sohd manure is a combination of feces, urine and some bedding

and no extra liquid is added, while liquid manure has water added to form a

floatable mixture.

Many factors have to be considered when choosing the type of manure

management system for a specific animal production operation. These

include: the livestock type (cattle, hogs, poultry), the age and size of animal,

the feed required, the housing system, the bedding required or available, the

cropping practice of the area, proximity to waterways, proximity to

neighboring residential areas and the personal preference of the livestock

grower.

One of the most common and basic manure treatment facility is the lagoon

system, which may be used regardless of the animal managed in the

operation. Lagoons originated as a means of storing and conserving fertilizer

nutrients from the waste of animals up until the time it was applied directly

to the soil.

Lagoons act as digesters in which two major types of bacteria decompose

organic matter into liquids and sludge: anaerobic bacteria, typically present

in the intestinal tract of warm blooded animals and are active under oxygen-free conditions; and aerobic bacteria which are active only in the

presence of dissolved oxygen, resulting either from diffusion across the water

surface of the lagoon, or as a result of photosynthesis by algae. Lagoon

systems, however, yield a loss of nutrient value. Further, as malodors are

prevalent in most lagoon systems, frequent sludge removal is required,

especially if the lagoon is undersized for the operation and there is a need for

water level control and mechanical aeration systems to keep the lagoon in

operation. Such removal may increase the cost of the operation.

The malodors released from the manure present a major environmental

problem. Odor in hvestock operations is the direct result of the decay of

organic materials, be it feces or feed products and the resulting high

concentrations of ammonia, hydrogen sulfϊde, carbon dioxide, trace gases,

volatile organic compounds, methane dust and some pathogens.

The odor may be treated by ventilation, either by natural wind-propelled

ventilation, by mechanical ventilation using fans, ventilation, tunnels, etc.

Alternatively, the released odor may be reduced by the use of biofilters or

biomass filters, or by covering the storage structures (e.g., lagoon) with

either high density polyethylene materials or straw, corn stalks, etc., the

latter having the limitation that they become soaked with water and thus

sink, thereby contributing to manure sohd and odor problems in the storage

tank. US patent 3,884,804 deals with a method of treating animal wastes to

reduce odors produced by the decomposition of the organic materials in the

animal wastes. The following systems were discussed:

1. Contacegon particles, comprising sohd catalyst particles having surface

portions which are wetproofed by treatment with a hydrophobic material

, are floated on the surface of a watery mass containing the animal

wastes. The Contacogen particles promote the oxidation by air of the

odoriferous compounds produced by the degenerative breakdown of the

animal wastes. The Contacogen particles are sohd catalyst particles

which have been treated with a hydrophobic agents selected from the

group consisting of polytetrafluoroethylene, silicon resins and silica

colloids made hydrophobic by surface conversion to silicone. The catalyst

particles may be any substance presenting a large specific surface area

which has the property of catalyzing the oxidation by air of the

odoriferous compounds produced by the degenerative breakdown of

animal wastes. Activation carbon is such a catalyst.

2. Floating on the surface of a watery mass of animal wastes solid catalyst

particles selected from the group consisting of carbon and activated

carbon particles having surface portions of a hydrophobic material which

forms a discontinuous film thereon. The hydrophobic materials are

selected from the group described above. The size of carbon particles may

vary from about 10 micron (for a powder) to relatively large size granules

(about 1 cm). It was surprisingly found that hydrophobic particles of a smaller size than

10 microns are highly effective in treatment of liquid and semi-sohd

animal manure. More specifically, floatable hydrophobic particles having a

diameter of less than lμm in association with floatable, high porous

particles, having both hydrophilic and hydrophobic groups play an

important role in a highly effective management of animal waste.

More specifically, in accordance with the present invention, a new distinct

surface layer is formed (hereinafter referred to as the "interface layer")

over the upper face of the animal waste pool. Same interface layer has

multiple functions, based on its chemical composition and physical

structure, and provides changes in the properties and composition of the

upper pool layers. The interface layer may contain different components,

in accordance with the desired function to be achieved. Said components

are selected from the group comprising:

(a) floatable, substantially hydrophobic nano-range particles having a

diameter of less than 100 nm, and preferably, 2-40nm (hereinafter

referred to as "component A"). Such particles may be, for example,

modified silica ( for example, alkyl-silica), modified minerals (such as,

alkyl-mineral materials), and others.

(b) floatable, high porous (over 50% of the material consisting of pores)

particles having both hydrophobic and hydrophihc groups (hereinafter

referred to as "component B"). Such materials may be for example, perhte, claydite, plant-material residues (wood pieces, wood pulp,

sawdust, straw, etc.). Same particles, having a diameter of >lμm, may

optionally be associated with (1) said substantially hydrophobic

nano-range particles; with or without (2) substantially hydrophilic

nano-range particles (hereinafter referred to as "component C") having a

diameter of less than 100 nm, and preferably, 2-40nm. Such particles

may be, for example, silica, alumina, and other oxygen-containing

minerals; and/or (3) photo-catalysts capable of decomposing organic

material and malodors; and/or (4) aerobic bacteria capable of degrading

organic waste materials.

(c) active carbon particles in association with component A and/or

component B.

More specifically, component A represents nano-size, non-porous,

mechanically rigid and highly dispersable particles whereas component B

represents porous, micron-to-cm size, mechanically brittle particles.

Furthermore, a particle of component A has a huge outer convex surface

per volume or weight, whereas a particle of component B has a huge inner

concave surface due to the pores and holes.

Particles of component C have similar physical and mechanical properties

suach as particles of component A. In spite of the above differentiation between components A and B, both

particles may be of the same or different materials and they may be

subjected to the same or different pre-treatment procedures for rendering

hydrophobic and/or hydrophilic properties.

SUMMARY OF INVENTION

It is an object of present invention to provide a novel system and method

for the treatment of liquid and semi-solid animal waste. The animal

waste includes feces, typically also urine, and at times, also animals

bedding material and food remains. It is a further object of present

invention to provide a treatment means of same animal waste in a

receptacle suitable for collecting such waste. The receptacle may be a

receptacle which directly receives the animal waste preferably positioned

underneath the animal growing facility. Alternatively, the receptacle

may be a reservoir situated outside the animal growing facility to which

the animal waste is transferred through pipes or channels, by the use

gravity caused flow or various pumping arrangements, etc. the receptacle

containing the animal waste will be referred to herein as the "animal

waste pool".

It is yet an another object of present invention to prevent, reduce and/or

remove malodors typically associated with such animal wastes. The present invention provides, inter alia, a method and system for managing waste

associated with animal production, in which the organic substances and

malodor resulting therefrom are decomposed and/or adsorbed by a

particular porous particulate material of the invention. Consequently, a

farther object of present invention is the provide of fertilizer compositions

formed following a treatment of animal waste in accordance with the present

invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

In accordance with present invention, an interface layer is formed over the

upper face of the animal waste pool. This interface layer comprises

particulate matter which acts in changing the properties and composition

of the upper pool layer by virtue of the interface layer functional

properties. Such functional properties include one or more of the following:

(1) ability to adsorb organic matter present in the pool; (2) ability to

catalytically act in degrading volatile malodorous substances; (3) the

ability to form a barrier for malodor transfer from the pool to the

surrounding atmosphere while keep maintaining water evaporation

capability or, if desirable, (4) the ability to biologically degrade organic

waste through bacteria which are contained within the interface layer.

Consequently, the interface layer may demonstrate the following multiple

functions: 1. An interface layer consisting of component A:

Component A forms a semi-impermeable membranous barrier preventing

malodor transfer from the waste pool to the external atmosphere. Such a

barrier allows transfer of relatively small molecules (such as, for example,

water) from the pool to the surrounding atmosphere. In case of stabile

interface layer (consisting of, for example, methyl-sihca particles) it may

remain efficient in controlling odor for about a week before it loses its

mechanical stabihty. Whenever labile interface layer is formed (consisting

of, for example, n-butyl- silica particles) it may remain efficient for a

shorter time. However, the last case may fit better the procedures involved

in controlling odors released from continuously slow moving or flowing

waste pools.

2. An interface layer consisting of various combinations of

component A and component B:

The process for controlling malodors associated with liquid or semi-sohd

animal waste may result in providing useful fertilizers as by-products.

Several possibilities exist, among them are:

(a) Providing an organic-based fertilizer:

(I) An interface comprising a combination of component A (for example,

methyl- silica) and component B (for example, high porosive perlite) and optionally component C (for example, silica) to form an interface

layer in which a certain amount of nano-particles (components A and

optionally component C) are adsorbed onto the surface of porosive

particles (component B) which serve as carriers. Such an interface

layer, containing an appropriate amount of nano-particles, functions as

a semi-permeable membrane allowing the release of water vapors but

prevent release of other gases thus maintaining the malodors within

the pool isolated from the surrounding atmosphere. Water molecules of

the upper layer which are evaporated (in a subhmation-like process)

into the surrounding atmosphere, continuously substituted by other

water molecules coming from the liquid phase. Furthermore, the

addition of nano-range hydrophilic particles (component C) to a

combined particulate combination of components A and B provides an

improved semi-permeable interface layer due to the wet of nano-range

hydrophilic particles with the evaporated water to form a "wet-filter".

Such a treatment of the waste pool will result in a partial or complete

adsorption of organic material onto the interface layer. Consequently,

the interface layer, or its residual, containing the adsorbed organic

substance may be used, following its removal from the pool, as a carrier

for prolonged release organic ingredients and/or nutrients useful in

fertilization of various crops. It should be pointed out, that an interface layer that consists of

combination of component A and component B, and optionally

component C retains simultaneously hydrophobic character (provided

by components A and B) and hydrophilic character (provided by

component B and optionally by component C). The combination of

components A and B , and optionally C, is dependable on and

associated with physical forces. For example, the nano-range

substantially hydrophobic particles may be adsorbed, attached, or

attracted to component B particles by means of electrostatic forces,

such as Van-Der-Vaals forces. When particles of component C are

involoved, additional forces, such as hydrogen bonds, may be involved,

as well. However, it should be emphasized that the formation and

function of the interface layer is dependable upon the enormous

particle's surface area per volume, or weight (specific area). Thus, the

surface of 1 gram of nano-range particles has a surface area of 200

square meter and may reach twice this number. Consequently, a

combination of porous B particls with nano-range particles (such as, for

example, methyl-silica and perhte) contains a very high ratio of

surface area to volume, forms an equivalent interface layer that

functions similarly to the one described above.

It should be further emphasized, that it is desirable to wet by aqueous

solution of glycerine (or of a glycerine-like material), the floatable particulate material, consisting of particles of component B adsorbing

nano-range particles, to prevent the removal of powdery nano-range

particles while spreading the particulate material over the waste pool.

Such a wet treatment may include sprinkling of the particulate material

using solution drops, before use or during manufacturing process,

followed by hermetic packaging.

(II) An interface comprising particles of component A in association

with particles of component B, having photo-catalyst (for example,

Tiθ2) impregnated or adsorbed, either onto surface of particles of

component A and/or surface of particles of component B. Such an

interface layer, that may optionally contain particles of component C,

may consist of catalyst-bound nano-range substantially hydrophobic

particles (for example methyl-silica) adsorbed onto the surface of

particles of component B and/or catalyst-bound particles of component

B (for example, a high porous perhte) adsorbing onto particles of

component A, and/or catalyst-bound particles of component A adsorbed

onto surface of catalyst-bound particles of component B. The

photo -catalytic compound maintains the decomposition of malodors

evolved and/or reached to surface of the pool. Such a treatment of the

waste pool will result in a partial or complete adsorption of organic

material onto the interface layer. Consequently, the interface layer, or

its residual, containing the adsorbed organic substance may be used, following its removal from the pool, as a carrier for prolonged release

organic ingredients and/or nutrients useful in fertilization of various

crops.

(b) Providing an inorganic -based fertilizer:

A layer interface may comprise a combination of a proper amount of

component A, component B (containing an aerobic bacteria) and

optionally component C. Such an interface (containing, for example,

methyl silica adsorbed onto the surface of a high porous perhte in

which aerobic bacteria are implemented within its pores, and

optionally paticles of component C) functions as a semi-permeable

membrane allowing the release of water vapors while maintaining the

malodors within the pool isolated from the surrounding atmosphere.

Such a treatment of the waste pool will result in a partial or complete

adsorption of inorganic residual material remaining following the

bacterial decomposition of organic substances accumulated onto the

interface layer. Consequently, the interface layer, or its residual,

containing the adsorbed inorganic materials may be used, following its

removal from the pool, as a carrier for prolonged release inorganic

ingredients and/or nutrients useful in fertilization of various crops.

It should be pointed out that an interface layer comprising a

combination of component A, in association with a photo-catalyst, and component B containing aerobic bacteria, is well within the scope of

present invention, as well.

As a matter of principle, it should be emphasized that adding particles

of component C (nano-range hydrophilic particles) to a combination of

particles of components A and particles of component B will result in

adsorbance of hydrophilic particles of component C onto the surface

and within the pores of particles of component B. The combination of

these three components, provides additional advantages, such as an

increase of stability of the interface layer against outside mechanical

disturbance (winds, waves etc). Furthermore, the presense of

hydrophilhc particles on the surface and within pores of particles of

component B makes during the time the particles heavier due to

absorbing water from the waste pool and thus enhances the gases

anti-release pressure, resulted in reducing release of malodors to the

surrounding atmosphere.

An insertion of active carbon particles as a component (in addition to

either component A and/or component B, with or without component C) in

the interface layer provides some advantages such as, an increase in gases

adsorption (including malodors), in ionic materials adsorption, resulting in

removing an excess amount (which may be toxic) of N- and/or P- and/or K

- based inorganic compounds. Furthermore, black particles intend to

adsorb sunlight and consequently to heat the pool, resulting in enhancing the biological degradation processes. The particulate material which forms

an interface layer may be pre-treated in a manner so as to enable it to

float over the surface of the liquid for a period of time. Such a treatment

may include sintering (forming closed gas/air filled pores which render the

particulate material floatable); chemical modification of the particulate

material to make it carries the proper proportion of hydrophobic and/or

hydrophilic groups; binding catalytic compounds to the particulate

material; adsorbing particulate materials of various sizes to one another;

associating (impregnating, adsorbing etc.) the particulate material with

bacteria, typically aerobic bacteria, which then colonize the pores in the

material (pores are considered here as free spaces not only within the

particles, but also as spaces between neighbor particles . It should be

noted that an important requirement of the particulate material which

forms the interface layer is that it has an overall specific gravity less than

that of water so that it will remain afloat on the top surface of the waste

pool. With some of the particulate matter used as the interface layer

material, this may be a result of the porosity of the component B particles

and the sintering thereof to close some of the pores to form closed air

pockets. The porosity of the component B particles used in accordance with

the invention is typically above 50% and preferably within the range of

70-99%. At times, as already mentioned above, the interface layer-forming

particles may be treated by chemical binding or adsorption thereto

catalytic components, e.g. photo-catalysts. Examples of catalysts are heavy

metal complexes or oxides, such as titanium oxide (Tiθ2). The catalysts, if

present on the particles, serve for the degradation of volatile organic

matter released from the waste pool. This reduces the malodors which

are typically associated with animal waste. It should be noted that silica

or some minerals that have some catalytic properties by their own, may be

combined with other catalytic component to yield a more pronounced

effect.

The invention thus provides a method for treatment of liquid or semi-sohd

animal waste, comprising:

(a) collecting the animal waste into a receptacle, to form a liquid

or semi-sohd waste pool;

(b) introducing onto the waste pool a floatable particulate

material selected from the group comprising component A,

component B, active carbon or any combination thereof, with or

without catalysts and/or microorganisms, which forms an

interface layer over a top surface of said pool, said interface

layer having an effect on the composition of the pool's upper

layer or its interaction with the overlaying atmosphere; and (c) incubating said particulate material in said pool for a time

sufficient to yield said effect, while periodically, if necessary,

replacing or replenishing the interface layer with new such

said material.

Said effect may, in accordance with one embodiment, be the prevention or

reduction of malodors. For that purpose, the treatment in accordance with

present invention will proceed at least for a time until the waste material

solidified or otherwise change its properties to avoid malodor.

In accordance with another embodiment of present invention, said effect

comprises adsorption or degradation of organic matter in the upper layer.

The porous hydrophobic particulate material, which partially or

completely, forms the interface layer, adsorbing the organic material

within its pores and subsequently removing it from the upper layer of the

waste pool. This will give rise to depletion of organic material from the

pool's upper layers which gives rise to some drift of organic material from

lower layers to upper layers. If necessary, the interface layer may be

replaced or replenished with fresh interface layer forming material,

thereby retaining the capacity to continuously adsorb organic material

from the pools' upper layers.

The animal waste is treated to eventually obtain a particulate product

useful as an organic fertilizer. Such an interface layer-fertihzer composition, which is substantially detoxified is also within the scope of

the present invention.

It should be noted that the particulate materials used in the formation of

the interface layer are preferably nutritionally inert and valueless, and

only when having adsorbed thereon organic substances may be useful for

fertilization.

The system of the invention may also comprise black particles as means

for heating the animal waste to accelerate the waste treatment process.

Additional heating means may include, for example, waste treatment

facility covered by a greenhouse-like structure to obtain a greenhouse

heating effect.

Hydrophobic particulate material may be obtained by various procedures

known in the art. The procedure employed may depend, inter alia, on the

material from which the particulate material is made of. According to one

embodiment, at least part of the interface forming particles consist of one

or more materials selected from the group of compounds named "oxides"

and/or compounds containing oxide group(s), which typically contains

hydroxyl groups on their surface. The hydrogen atoms of the hydroxyl

groups may be substituted by hydrophobic groups, such as -alkyl,

-Si-(lower alkyl)3 and others. According to another embodiment of the process of present invention, the

covalent bonds of the hydrophobic groups are relatively stabile (for

example, when the alkyl is a methyl group) and consequently, there will

be no subsequent dissociation of the hydrophobic moieties from the

particulate material forming the interface layer and same particulate

material will continuously float at the top surface of the waste pool until

being manually removed. Methylation of hydroxyl groups, is a well know

procedure. In general, oxide particles, e.g. silica particles (Siθ2) are first

heated to remove physically adsorbed water therefrom, then, the particles

are reacted with a suitable reagent, such as, for example, n-butanol,

Cl-Si-(CH3)3 or poly-methylsiloxane at an elevated temperature, wherein

the hydrophobic group (-n-butyl or -Si-(CH3)3) substituting the hydrogen

atoms of the hydroxyl groups on the surface of the particles. The reaction

duration, concentration of methylating agent and temperature employed

during the reaction will determine the degree of methylation and

consequently, the floatation characteristics of the particle.

The binding of the hydrophobic group may, if so desired, forms a relatively

unstable bond, which in the presence of water, may undergo hydrolysis to

release the corresponding alcohol. For formation of a relatively unstable

bond, a similar treatment may be performed, however at lower

temperatures and using different reagents, such as for example, alcohol of

the general formula R-OH (R represents low alkyl) to form the relatively

unstable bond -Si-O-R, wherein the hydrophobic group is subsequently hydrolyzed to release the corresponding alcohol (R-OH). Consequently, the

hydrolyzed particulate material may regain in time its hydrophilic nature,

and as a result it may sink into the aqueous medium. Furthermore, the

dissolved alcohol may inhibit any bacterial degradation (in particular,

anaerobic) occurring in the anoxic areas of the liquid, thereby minimizing

the conversion of the organic substances in the waste into methane gas.

Such inhibition is desirable to prevent full degradation of organic

substances which become adsorbed onto the particulate material, thus

permitting the use of these organic material-carrying compositions, for

example, as fertilizers.

It should be pointed out that optionally, and when so desired, the

hydrophobic groups may be bound to the hydroxyl groups by means of

non-covalent binding, for example, hydrogen bonds. Such a link, or

association, is within the scope of present invention, as well.

It will be appreciated by the artisan that the interface layer formed at the

top surface of the waste pool may contain particulate material treated by

more than one of the above described prior treatments or equivalents

thereof or by any other one or more treatments to render the particulate

material floatable. Thus, a particle may be both sintered and carry

chemically bound hydrophobic groups thereon. Further, the interface layer may comprise particulate materials having different levels of

hydrophobicity.

The particulate materials of the invention may be treated silica particles,

treated mineral particles and/or treated plant material residues, all of

which are known to contain a significant content of oxygen atoms and

hydroxyl groups on their surface. Further, the particles may be of a porous

hydrophobic polymer, such as hydrophobic polyesters or any other porous

material which is, or may be treated to become, a floatable material.

Within the scope of the present invention, mineral particles include, but

are not limited thereto, silica minerals, e.g. perlites, clay minerals, e.g.

bentonite and claydite or alumina minerals or any other mineral being

porous and containing a significant content of oxygen. Plant material

residues include, but are not hmited thereto, husk straw, peat, dry stems,

sawdust, etc.

According to an additional embodiment of present invention, the volatile

materials released from the waste pool are decomposed by a catalytic

component present in the interface layer at the top surface of the waste

pool. Such catalytic components are preferably photo-catalysts which are

known to the person versed in the art. They include, but are not hmited

thereto, heavy metal complexes, such as non-poisonous complexes of Fe,

Cu, Co, or Ni or metal oxides, such as Tiθ2 or AI2O3. The catalytic components may be either dispersed in the interface layer or be adsorbed

onto the porous particulate material. One way of adsorbing the catalytic

components onto the porous particulate material is by means of

electrostatic interactions. This may be accomplished by spraying the

mixture of particulate material and catalytic component with a hot and

dry air (optionally ionized), which gives rise to build-up of electrostatic

charges onto the particle surface.

The particulate material of the invention may be of various sizes ranging

from nano-range particles having a diameter of less than lμm

(components A and C), preferably in the range of 2-50 nm The particulate

material of the invention may be of various sizes ranging from nano-range

particles having a diameter of less than lμm, and particles having

diameter larger than lμm (component B), including particles having a

diameter in the range of millimeters to several centimeters. Due to their

small size the nano-range particles have a relatively greater surface area

comparing to particles of component B and therefore they suppose to

exhibit preferable floating capabilities. However, nano-range particles are

porous-less and their very small size may result in their drawn away from

the waste pool by air movement. Thus, according to the present invention

it is preferable that the nano-range particles be adsorbed onto surface of

floatable component B particles. The adsorption of nano-range particles

onto surface of component B particles may be achieved, for example, in the manner described above in connection with the adsorption of catalytic

components onto the particulate material or by any other suitable means

for association of the two types of particulate materials.

According to a further embodiment of the invention, the interface layer

may further comprise active carbon particles (e.g. graphite, charcoal

particles). Active carbon particles are known as having the capabihty of

absorbing gases and may thus prevent, or at least reduce, the amount of

noxious odors released from the waste pool. Further, as such particles are

typically black, they may function to absorb sunlight and heat the pool

facilitating the biological degradation process. At times, the system may

comprise other or additional heat-absorbing particles, such as dark-colored

rubber particles (may be prepared from used tires). Heating means with a

greenhouse-like cover structure may also be used for waste pool warming.

Yet further, the interface layer may comprise bacteria, preferably aerobic

bacteria, carried within the pores of the component B particles for

biological degradation of the organic substances in the animal waste. The

bacteria are typically contained in pores having a diameter in the range

from about 1 to about 50 μm, while smaller pores, having a diameter in

the range of nanometers may function as trap means for the organic

substances (the organic substances will be adsorbed in these traps by

hydrophobic interaction). Thus, organic and inorganic materials are

trapped in the bacteria-free pores. The aerobic bacteria will lead to the partial decomposition of the organic

substances which may at times be desirable. The bacteria may originate

from the waste in which bacteria is inherently present or from

impregnation of the particles with such bacteria prior to their introduction

into the waste-containing pool. Any available suitable bacterial cultures

may be used for either impregnation, adsorption or growing (followed by a

dry-lyophilization process) within of the pores of the particulate material.

The method of the invention may be a batch process, wherein waste is

introduced into the receptacle before beginning of the treatment, or a

continuous process, wherein animal waste is continuously, or periodically,

added to the pool. In any case, the interface layer forming material may be

replaced or replenished with new particulate material several times

during the waste treatment procedure. The interface layer and its

particulate material is preferably collected, optionally dried, and may then

be subsequently used as prolonged-release fertihzing compositions as

described above. The advantage of such fertilizer compositions is that the

organic substances accumulated in the pores of the particulate material

are released into the soil in a slow release manner.

The following examples are provided merely to illustrate the invention and

are not intended to limit the scope of the invention in any manner. EXAMPLES

Preparation of butylated silica nano-particles

Sihca nano-range particles (diameter of 2-50 nanometer) were modified by

reacting the same with n-butanol to yield hydrophobic butylated sihca

particles silica- [Si- 0 -n-butyl] _n (hereinafter referred to as butyl-silica).

Excess of butanol was removed from the reaction system by evaporation.

The particles were then heated at 200-260°C followed by their cooling at

room temperature to yield a white powder-like particulate material.

Urine treatment with butyl- sihca nano-range particles

Nano-range n-butyl silica particles (2-25nm) were introduced step-wise

(eight portions of 2 gr. each) into a beaker containing a sample of swine

urine (200 ml), until obtaining a snow-like interface layer at the top

surface of the liquid. After each addition of the particles the system was

mixed for 2-3 min. The initial pH of the system was 6.0, and the treatment

was carried out at 18° C, with air humidity of 65%.

The malodors associated with the urine were substantially eliminated

after 30 minutes. After 24 hours the liquid within the beaker obtained a

pasty-like structure, substantially free of odors (pH of the liquid was 7.0).

After an additional week, the pasty like substance lost 50% of its weight as

a result of water evaporation and became an odorless lumpy powder. After additional two weeks, the material within the beaker became dry and had

a powder-like structure (32 gr) comprised of the particles carrying organic

substances, including about 16% (by weight) of ureic acid.

These results indicate that the particles were able to withdraw from the

urine the organic substances, prevent the formation and release of odors

from the hquid and provide substantially clear water, which evaporated

from the system.

Preparation of methylated nano-range particles

Sihca particles (diameter of 2-250nm) were treated to carry methyl groups

on the surface thereof by reacting the same with trimethylchlorosilane

under gaseous conditions, for an 1 hr, at 250-300°C, during which

hydrochlori.de was released from the system.

The efficiency of the above described butylated or methylated sihca

particles, a combination of such particles, or a combination thereof with

component B particles was determined.

Results

The efficiency of the following particles in preventing the formation and

release of malodors was determined: silica- [Si-0-Si-(CH3)3]n (hereinafter

referred to as CH3-silica); CH3-silica + n-butyl-silica (50%: 50%); perlite (having a diameter of 2-3 mm and a porosivity of 95%) + CHβ-Silica

(98%:2%); claydite (having a diameter of 1.5-3 mm and porosivity of 50%)

+ CHβ-Silica (98%:2%); and active coal particles (having diameters of

3-7mm) + CHβ-Silica particles (98%:2%). The B particles were dried at

temperature of 105 -120 C.

The treated alkyl-silica particles were adsorbed onto the mineral derived

or coal particles by electrostatic interactions. The tests were conducted as

described above. Samples of pig urine and/or pig excrements were placed

in a beaker, onto which the particulate material(s), was (were) introduced.

The samples included urine alone or urine mixed with water (v/v 1:4); pig

excrements alone or excrements mixed with urine (1:1). The time after

which odors were no longer discernible above the interface layer was

measured. Table I provided the results obtained for each type of particles

and samples:

Table I

In each sample, the interface layer was effective until total sample dried

out. At the end of the process, the dry material in each case includes

organic substances absorbed unto the interface layer creating a crust-like

yellow-brownish solid layer. No malodor was detected, during the entire

process.

These results show that in the presence of the particulate material of

present invention, the formation and release of malodors associated with

the animal manure was eliminated after a short period of time.

CH.₃-silica particles: a crust was formed at the top of the system with all

samples. This crust layer becomes visible in 1-2 days and gets its final

crumbly appearance when the sample is dried-out (within 10-20 days).

C₄Hg-silica particles: After about 24 hours a paste-like layer was formed at

the top surface of the samples, after which a powder-like material

containing ureic acid (16%) was obtained. The system containing urea and

water became dry after about 12 days. Samples containing pig excrements

became a lumpy material wherein the organic material is adsorbed onto

the particulate material. When the sample contained a mixture of

excrements and urea, the lumpy material was coated with a powder-like

substance.

CH..-silica + butyl-silica: The sample became dry after a week. A lumpy

material containing the organic substances adsorbed onto the particulate material was obtained with the sample containing excrements, and

covered with a powder like substance, when the sample contained also

urine.

Perhte -t- CHa-silica: A powder-like material was obtained when using

urine or a mixture of urine and water It took 14 days until total dry-out at

the room conditions. A lumpy material was obtained in the case of samples

containing excrements which was coated with a powder like material

when the sample contained also urine. All individual samples got dry

within 2-3 weeks. Particulate material of the interface layer, dissolved

copmounds, solids and organic substances created a sohd crust.

Claydite + CHa-silica: A paste like (increased viscosity) layer was formed

at the top surface of the samples after 3-4 days of incubation. During the

treatment the viscosity has increased due to water evaporation while the

remaining liquid form a kind of thick colloid thixotropic paste which

became thicker and thicker until it was completely dried- out.

Active carbon + -CHa-particles: a clear separation between the aqueous

phase and organic phase was observed, especially in the case using

samples containing urine and water. In this case, no increase in medium's

viscosity was observed and active carbon which have adsorbed organic

materials sunk to the bottom. As a result, the liquid has steadily became

clearer and lost its black color.

Claims

CLAIMS:

1. A process for treating liquid or semi-solid animal, including human,

waste, and controlling malodor associated with same waste, comprising:

(a) collecting said animal waste into a receptacle, to form a waste

pool;

(b) introducing onto said animal waste pool floatable, particulate

material which forms an interface layer over a top surface of

said waste pool; said interface layer has multiple functions,

based on its chemical composition and physical structure, and

provides changes in the properties and composition of the

upper pool layers and/or its interaction with the overlaying

atmosphere. The interface layer, in accordance with the

desired function to be achieved, may contain at least one

component, selected from the group comprising:

(I) floatable, substantially hydrophobic nano-range

particles having a diameter of less than lOOnm, and

preferably 2-40 nm (referred to as "component A");

(II) floatable, porous particles having both hydrophobic

and hydrophilic groups (referred to as "component

B"). Same particles, having a diameter of >lμm, may

optionally be associated with (I) said substantially

hydrophobic nano-range particles; with or without (2) substsntially hydrophihc nano-range particles

(referred to as "component C") having a diameter of

less than lOOnm, and preferably, 2-40nm; and/or (3)

photo -catalysts capable of decomposing organic

substances and malodors; and or (4) aerobic bacteria

capable of degrading organic waste materials;

(HI) active carbon particles in association with component

A and/or component B;

(c) incubating said interface layer in said waste pool for a time

sufficient to yield an effect of either of said functions, while

periodically, if necessary, replacing or replenishing the

interface layer with new such particles.

2. A process according to claim 1, wherein said component B is a high

porous particle having 50-95% porosity.

3. A process according to claiml, wherein said floatable component A

particle is inherently hydrophobic or is an originally hydrophilic particle

pre-treated to render it substantially hydrophobic.

4. A process according to claim 3, wherein said particle is selected from the

group of non-porous compounds named "oxide" and/or oxide-group(s) -

containing substances.

5. A process according to claim 3, wherein said particle is alkyl-silica.

6. A process according to claim 1, wherein said floatable component B

particle containing both hydrophobic and hydrophilic groups, or inherently

hydrophobic or hydrophihc particle pre-treated to render it partly

hydrophilic or partly hydrophobic, respectively.

7. A process according to claim 6, wherein said particle is selected from

the group of porous compounds named "oxide" and/or oxide-group(s) -

containing substances.

8. A process according to any of claims 1 to 7, wherein either component A

and/or component B and/or component C particles are selected from the

group comprising mineral-derived particles.

9. A process according to claim 8, wherein said mineral particle is selected

from the group comprising silica minerals, alumina minerals and clay

minerals.

10. A process according to claim 9, wherein said sihca mineral is pertile

and said clay mineral is bentonite or claydite.

11. A process according to claim 10, wherein component B is selected from

the group comprising perhte, bentonite and claydite.

12. A process according to claim 7, wherein component B is a plant

material residue comprising amorphous oxide.

13. A process according to claim 12, wherein said plant residue is selected

from the group comprising husk straw, peat, dry stems and sawdust.

14. A process according to claim 6, wherein said pre-treatment of

component B particles included sintering of the porous particulate

material to form air-filled pockets therein, which render the particles

floatable.

15. A process according to claims 3 and 6, wherein said pre-treatment

includes chemical binding of hydrophobic groups at least on the surface of

said particle.

16. A process according to Claim 15, wherein said pre-treatment is

alkylation of functional groups present on the surface of said particles.

17. A process according to claim 1, wherein said interface layer comprises

catalytic components, for catalytic decomposition of volatile substances

released from said animal waste; said catalytic component is introduced

onto the particulate material before or after introduction of said

particulate material into said pool, or while being adsorbed onto said

particulate material.

18. A process according to claim 17, wherein said catalytic component is a

photo-catalytic component, being a complex or an oxide of a heavy metal.

19. A process according to claim 18, wherein said heavy metal complex

comprises a non-posinous heavy metal selected from Fe, Cu, Co, or Ni.

20. A process according to claim 18, wherein said metal oxide is Tiθ2 or

Al₂O .

21. A process according to claim 1, wherein said component C particles are

22. A process according to claim 1, wherein said interface layer conists of

particles of component A and C adsorbed onto the surface of particle of

component B.

23. A process according to claim 1, wherein said interface layer comprises

active carbon particles or carbon-derived substances introduced into said

waste pool before or after introduction of said particulate material or while

being adsorbed onto said particulate material.

24. A process according to claim 1, wherein component A and C particles

having the diameter of 2-50 nm.

25. A process according to claim 1, wherein component B particles having

a diameter in the range of 1 μm to 5 cm.

26. A process according to claim 1, wherein said interface layer comprises

a combination of component A and component B particles.

27. A process according to claim 26, wherein said interface layer

comprising 1-5% (by wt.) component A and 95-99% (by wt.) component B.

28. A process according to claim 1, wherein component B particles

containing bacteria active in degradation of organic, and/or other

biodegradable, substances in said animal waste.

29. A process according to any one of the preceding claims, being a

batch-wise process.

30. A process according to any one of the preceding claims, comprising

continuously or periodically addition of animal waste to said receptacle.

31. A floatable, particulate material containing at least one component,

selected from the group comprising:

(a) floatable, substantially hydrophobic nano-range particles having a

diameter of less than 100 nm, and preferably, 2-40 nm (referred to

as "component A");

(b) floatable, porous particles having both hydrophobic and

hydrophilic groups (referred to as "component B"). Same particles,

having a diameter of >lμm, may optionally be associated with (1)

said substantially hydrophobic nano-range particles; with or without (2) substantially hydrophihc nano-range particles

(referred to as "component C") having a diameter of less than

lOOnm, and preferably, 2-40nm; and/or (3) photo-catalysts capable

of decomposing organic substances and malodors; and/or (4)

aerobic bacteria capable of degrading organic waste materials;

(c) active carbon particles in association with component A and/or

component B;

which after being introduced onto a pool containing hquid or

semi-sohd animal, including human, waste forms an interface

layer over a top surface of said waste pool; said interface layer has

multiple functions, based on its chemical composition and physical

structure, and provides changes in the properties and composition of

the upper pool layers and/or its interaction with the overlaying

atmosphere.

32. A floatable particulate material, according to claim 31, having 50-95%

porosity.

33. A floatable particulate material, according to claim 31, being

inherently hydrophobic or being treated to render at least part

thereof hydrophobic.

34. A floatable particulate material, according to claim 31, wherein said

particle is selected from the group of compounds named "oxide"

and/or oxide-group(s) - containing substances.

35. A floatable particulate material, according to claim 31, comprising

silica-derived particles.

36. A floatable particulate material, according to claim 31, comprising

mineral- derived particles.

37. A floatable particulate material, according to claim 36, wherein said

mineral is selected from the group comprising sihca minerals,

alumina minerals or clay minerals.

38. A floatable particulate material, according to claim 37, wherein said

silica mineral is perlite and said clay mineral is bentonite or claydite.

39. A floatable particulate material, according to claim 31, comprising

plant material residues.

40. A floatable particulate material, according to claim 39, wherein said

plant material residues are selected from husk straw, peat, dry

stems and sawdust.

41. A floatable particulate material, according to claim 31, wherein said

particles are subjected to a pre-treatment.

42. A floatable particulate material, according to claim 41, wherein

component B porous particles are subjected to a pre-treatment

including sintering of at least part of said pores to form air-filled

pockets therein which renders said material floatable.

43. A floatable particulate material, according to claim 41, wherein said

treatment includes chemical binding of hydrophobic groups at least

to the surface of said particulate material.

44. A floatable particulate material, according to claim 31, comprising

nano range-particles having a diameter of 2-50 nm.

45. A floatable particulate material, according to claim 31, comprising

particles having a diameter in the range of 1 μm - 5 cm.

46. A floatable particulate material, according to claim 31, 44 and 45,

wherein said nano range-particles are adsorbed onto particles

having a diameter in the range of 1 μm - 5 cm, prior to introduction

thereof onto said animal waste pool.

47. A floatable particulate material, according to claim 31, wherein

component C is S-O2, AI2O3 or Tiθ2.

48. A floatable particulate material, according to claim 31, wherein said

nano-range particles of component A and component C are

adsorbed onto surface of particles of component B

49. A floatable particulate material, according to claim 31, wherein said

nano-range particles of component A and component C are

adsorbed onto surface of active carbon or carbon-derived particles.

50. A floatable particulate material, according to claim 31, carrying

adsorbed onto particle surface catalytic components, for catalytic

decomposition of volatile substances, including malodors.

51. A floatable particulate material, according to claim 50, wherein said

catalytic components are a heavy metal complex or oxide thereof.

52. A floatable particulate material, according to claim 51, wherein said

heavy metal complex comprises a non-posinous heavy metal

selected from Fe, Cu, Co or Ni.

53. A floatable particulate material, according to claim 51, wherein said

metal oxide is Tiθ2 or AI2O3.

54. A floatable particulate material, according to claim 31, wherein

component B particles containing bacteria active in degradation

of organic, and/or other biodegradable, substances.

55. A fertilizer composition obtained during, and/or following, and/or as a

result of a process for treating liquid or semi-solid animal, including

human, waste, and controlling malodor associated with same waste,

according to any of the preceding claims.