Fuel source and method of forming same from blending wastewater contaminants with biomass leftovers while cleansing wastewater

Abstract

A blending of sludge, grease and/or fats extracted from wastewater with biomass leftovers to form a fuel. The biomass leftovers may be pulverulent wood charcoal, pulverulent cellulose, vegetable oil, vegetable alcohol or any combination. The sludge, grease and fats are extracted while cleansing the wastewater of contaminants. The fuel may be burned to produce heat to drive a steam turbine. The cleansed water may flow to drive a water turbine. If a current population of bacteria cannot be sustained by the amount of contaminants in fresh supplies of the wastewater alone at a particular time, the previously extracted sludge may be used to supplement to help sustain the bacteria population. Likewise, when the amount of contaminants in fresh supplies of the wastewater exceeds what is necessary for the current population of bacteria to sustain itself, such excess may be extracted for use later or blended to form the fuel.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to forming fuels from a mixture of wastewater pollutants/contaminants and biomass leftovers, preferably during cleansing of wastewater. The pollutants/contaminants are extracted from wastewater preferably with mechanical devices, such as grease traps and sludge dewatering devices.

2. Discussion of Related Art

Wastewater treatment from residential sources requires the processing of organic based sludge, grease and fats. The grease may be, for instance, in the form used vegetable cooking oils and residue from cosmetic products such as face creams, body oils, etc. The fats may include animal fats.

Conventional wastewater treatment facilities use mechanical, chemical and biological processes to treat the organic based sludge, grease and fats. U.S. Pat. No. 6,767,464, whose contents are incorporated by reference, identifies various mechanical, chemical and biological processes employed conventionally to cleanse wastewater of contaminants.

Indeed, U.S. Pat. No. 6,767,464 recognizes that grease, fats and oils are discharged into water treatment systems, and grease and fat traps are sometimes employed to remove these materials. Costs are incurred at regular intervals for the removal and disposal of grease and fats from these traps, especially by users processing food. For the treatment of grease, fats and oils, the enzyme lipases, lipase releasing bacteria or bacteria capable of breaking down grease and fats could be used. These would convert the grease, fats and oils to glycerine, fatty acids, mono- and diglycerides. The breakdown products can then be diverted to the aerobic or anaerobic regions of the waste water treatment system, and can perform as an additional source of electron donor or carbon for nitrification or denitrification.

U.S. Pat. No. 6,709,593, whose contents are incorporated by reference, notes that the sludge is conventionally dewatered in a mechanical dewatering device, e.g., a filter press or decanter centrifuge, and the dewatered sludge is sent for final disposal.

The present inventor notes that the extraction of pollutants or contaminants from wastewater with mechanical processes, in contrast to chemical or biological processes, is a relatively inexpensive way to gather such contaminants, although chemical and biological processes are still necessary to cleanse the wastewater of toxic levels of the contaminants. Conventional wastewater treatment systems call for disposal of the mechanically extracted contaminants or for further chemical or biological processing of them. Disposal may, for instance, be at a landfill or in a natural body of water such as the ocean. Such disposal, obviously, is environmentally undesirable and generally entails paying a tipping fee to the operator of the disposal site or barge.

There are over 350 species of oleaginous, or oil-producing plants and thousands of sub-species. Two types of oil presses are used in both small and large scale vegetable oil processing. The most common type of oil press is the screw press. This press uses a large scale diameter screw inside a metal housing. The oil seed is fed into the top of the press and falls into the churning screw. As the seed is churned into a mash by turning threads of the screw, the oil is squeezed from the meal, or cake. The protein cake from the oilseed oozes from the side of the press and the vegetable oil dribbles from the bottom of the press.

Screw presses are available in sizes ranging from table-top models that produce 8 kilograms of seed per hour (2 liters of oil) to industrial models which can produce 4,000 kilograms of oil per day. Screw presses are available in electrical and Diesel powered models. Screw presses tend to be slow. A ram press is more efficient oil press design. This press uses a hydraulic piston inside of a cylinder to crush the oilseed. Ram presses can be powered by hand, by an electric motor, or by a Diesel engine.

After a vegetable oil is pressed, it is left to settle for a few days in horizontal settling tank. The vegetable gums and pieces of meal cake settle to the bottom of the tank. If it is to be used as a fuel, it should be pumped through a series of filters. Usually it is a four stage process, starting with 150 micron mash, then 70, then 25 and lastly a 10 micron fuel filter.

An ester is a hydrocarbon chain that, for certain compounds such as alcohol or amine, will bond with another molecule. A vegetable oil molecule is made of three esters attached to a molecule of glycerin. Vegetable oil is called a triglyceride. Vegetable oil is also called glycerol esters. About 20% of a vegetable oil molecule is glycerin. Glycerin makes vegetable oil thick and sticky. To transform vegetable oil into fuel, vegetable oil must go through the process of transesterification.

It would be preferable to find a use for the mechanically extracted contaminants that avoided the necessity to either dispose of them or further chemically or biologically treat them to render them non-toxic. Indeed, it would preferable to transform them into an energy source while purifying or cleansing wastewater.

SUMMARY OF THE INVENTION

One aspect of the invention relates to the addition of an additive to render extracted wastewater contaminants (domestic sludge, grease, fats) useful as a fuel source. The additive is preferably biomass leftovers such as pulverulent wood charcoal, pulverulent sawdust or other types of pulverulent wood or cellulosic based materials, such as from biomass. By pulverulent, the intent is to cover powder or fibrous forms.

Preferably, a sufficient quantify of the biomass leftovers is added to the mixture of the mechanically extracted wastewater contaminants to allow pressure from a press to be apply to form an ingot from the combination of mixture and additive. The ingot may be burned as a fuel source. If desired, lavender or other scents may be added to the contaminants after their mechanical extraction to neutralize their odors.

A further aspect of the invention concerns forming a source of energy while cleansing wastewater of contaminants. The source of energy is formed by blending extracted grease and/or fats, extracted dried sludge and leftover biomass. The grease and sludge are separately extracted from the waste water. The biomass leftovers may be pulverulent wood charcoal, pulverulent cellulose, vegetable oil, vegetable alcohol, or any combination thereof. Vegetable alcohol refers to ethanol alcohol, methanol alcohol, a combination of each, or other forms of alcohol derived from vegetable oil after undergoing transesterification.

Another aspect of the invention concerns compensating for fluctuations in demand for wastewater treatment by extracting sludge during times when that amount of sludge in fresh supplies of wastewater exceeds that necessary to sustain current population levels of bacteria in a water purifying region of the invention so as to either reuse the sludge later or blend it into a fuel. The sludge is returned during times when the amount of sludge in fresh supplies of wastewater is insufficient to sustain the current population levels of the bacteria in the water purifying region.

BRIEF DESCRIPTION OF THE DRAWING

The drawing is a schematic representation of wastewater purification, blending of extracted contaminants from the wastewater with leftover biomass to form a fuel mixture, and electricity generation from the turning of a water turbine with purified wastewater and from the turning of a steam generator from generating steam through the burning of the blended fuel mixture.

DETAILED DESCRIPTION OF THE INVENTION

The drawing shows a wastewater treatment and energy production system. It may be useful to consider the system to be subdivided into regions. The regions include an entry region, a water purifying region, a sludge drying region, a blending region, power generation regions, and a discharge region. The entry region includes a lifting pump 10 that pumps wastewater to a desired level within the water purifying region, such as within a basin. Mechanical cleansing equipment, such as a grease trap 20, is used to trap grease and/or fats in the wastewater. The trapped grease and/or fats are pumped or otherwise discharged to a grease tank 30 for storage.

The water purifying region may have capability for pollution water treatment 40, which may include conventional mechanical, chemical and/or biological cleansing treatments. For instance, such treatments may occur within a basin or vessel having an area containing aerobic and anaerobic bacteria (for biological treatment), an area containing cationic, anionic, and/or non-ionic polyelectrolyte flocculants (chemical treatment) and an area containing a clarifier 50 (mechanical treatment) that allows waste particulate matter to settle. A recirculating pump 60 may be used to recirculate the wastewater in the pollution water treatment 40. It may pump excess sludge to a sludge silo 70 for storage during times when there is an ample supply of fresh sludge in wastewater to sustain aerobic and anaerobic bacteria. It may pump sludge back to the pollution water treatment 40 from the sludge silo 70 if needed to sustain the anaerobic or aerobic bacteria during times when the amount of sludge in fresh wastewater is less than that necessary to sustain the aerobic or anaerobic bacteria. Such times are determined based upon whether fresh supplies of the wastewater alone contain sufficient quantities of contaminants for the bacteria to feed upon.

Thus, fluctuations in wastewater demand over time may be compensated to sustain the bacteria. Excess contaminants (sludge) that are beyond what is needed to sustain the bacteria population at current levels are extracted. Some portion of the excess is pumped back at a later time when the amount of contaminants in the wastewater is less than what the bacteria population needs to sustain itself at current levels. Such an ability prevents unwanted expansion of the bacteria population during peak demand times beyond what can't be sustained for long and prevents a sudden drop in the bacteria population at other times. The sludge extraction may be performed by mechanical techniques, which are cheaper to use than chemical or biological techniques.

The sludge drying region includes a sludge drying network 80 that dries the excess sludge from the sludge silo 70 and discharges the dried sludge to a stocking tank 90. A blender 100 is provided to blend together grease from the grease tank 30, dried sludge from the stocking tank 90 and biomass leftovers 110. The biomass leftovers may be pulverulent wood charcoal, pulverulent cellulose, vegetable oil, vegetable alcohol, or any combination thereof. Vegetable alcohol refers to ethanol alcohol, methanol alcohol, a combination of each, or other forms of alcohol derived from vegetable oil after undergoing transesterification.

The power generating region may be considered to have two aspects. The first includes an incinerator 120 that burns the mixture from the blender 100 to transform water into steam to drive a steam turbine 130 having an electric generator to generate electricity as the steam turbine is driven. The second includes a sand filter 140 that filters water leaving the purifying region and includes a water turbine 150 driven by the filtered, purified water to generate electricity with an electric generator that generates the electricity as the water turbine is driven. The water discharging through the water turbine may enter a discharging region to be further treated with a conventional ultraviolet treatment 160, depending upon whether the water is to be drinkable or used for agricultural purposes. If the water is merely be to discharged back into the same stream that the lifting pump 10 diverted the water initially, then the ultraviolet treatment 160 may not be needed.

While the foregoing description and drawings represent the preferred embodiments of the present invention, it will be understood that various changes and modifications may be made without departing from the scope of the present invention.

Claims

1. A method of energy production while cleansing wastewater of contaminants, comprising

cleansing wastewater of contaminants by extracting the contaminants from wastewater that render the wastewater unhealthy for human consumption, the contaminants including sludge and including at least one of grease and fats; and

realizing energy production by forming a fuel source, the fuel source being formed from drying the extracted sludge, and blending together the at least one of grease and fats, the dried sludge and biomass leftovers, the biomass leftovers being selected from a group consisting of pulverulent wood charcoal, pulverulent sawdust, pulverulent cellulosic materials, vegetable oil, vegetable alcohol, and any combination thereof.

2. A method of claim 1, wherein the realizing of the energy production includes burning the fuel source to produce heat.

3. A method of claim 2, wherein the realizing of the energy production includes driving a steam turbine with the produced heat to generate power.

4. A method of claim 1, further comprising cleansing the wastewater with a treatment process selected from a group consisting of a mechanical treatment process, a chemical treatment process, a biological treatment processes and any combination thereof, and filtering the cleansed wastewater.

5. A method of claim 4, wherein the realizing of the energy production includes driving a water turbine with the filtered, cleansed wastewater to generate power.

6. A method of claim 5, wherein the realizing of the energy production further includes burning the fuel source, transforming water into steam with heat generated from the burning of the fuel source, driving a steam turbine with the steam to generate further power.

7. A method of claim 6, wherein the realizing of the energy producuon further includes converting the power and the further power into electricity.

8. A method of claim 1, further comprising compensating for changes in wastewater demand by using a population of bacteria to digest additional contaminants in the wastewater;

determining whether fresh supplies of the wastewater alone are sufficient to sustain the population of the bacteria with sufficient quantities of the contaminants to feed upon and, if not supplementing the fresh supplies of the wastewater with the extracted sludge.

9. A method of claim 8, further comprising ceasing the extracting of the sludge while supplementing the fresh supplies of the wastewater with the extracted sludge.

10. A method of claim 9, further comprising resuming the extracting of the sludge after ceasing the supplementing when the determining finds that the fresh supplies of the wastewater alone have become sufficient to sustain the bacteria with sufficient quantities of the contaminants to feed upon.

11. A fuel source for energy production, comprising

a blend of biomass leftovers and extracted wastewater contaminants that render the wastewater unhealthy for human consumption, the contaminants includling dried sludge and including at least one of grease and fats; the biomass leftovers being selected from a group consisting of pulverulent wood charcoal, pulverulent sawdust, pulverulent cellulosic materials, vegetable oil, vegetable alcohol, and any combination thereof, the blend forming a fuel source that is combustible to burn.