Chemistry: molecular biology and microbiology – Apparatus – Bioreactor
Reexamination Certificate
2000-01-12
2002-03-05
Redding, David A. (Department: 1744)
Chemistry: molecular biology and microbiology
Apparatus
Bioreactor
C435S290400, C071S011000
Reexamination Certificate
active
06352855
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field of the Invention
This invention relates to reduction and contained decomposition of organic waste material, and more particularly, to a unitized process and apparatus for reducing and in-vessel composting raw food waste and biodegradable eating utensils and trays, yard waste, and newspapers, in combination with associated organic packing materials such as cardboard and paperboard containers, into two useful compost components, one liquid and one relatively dry.
2. Background of the Invention
According to published sources, in all, the United States generates approximately 208 million tons of municipal solid waste per year. Public and private sectors, alike, are facing increasing cost and difficulty in disposing of their enormous and increasing tonnage of solid waste and garbage in an environmentally sound and economically acceptable manner. Historically, refuse or garbage has been collected and disposed of by one of several inexpensive means, such as open burning, dumping in waterways, or dumping in common landfills.
As the ecological impact of such practices became evident, the demand for safer practices grew. Three methods emerged as environmentally suitable means for safe refuse disposal: (1) sophisticated landfills with costly structures and controls designed to prevent leaching into surrounding ground water; (2) controlled incineration; and (3) composting in which the compost product has a reduced toxicity suitable for subsequent disposal in a landfill. However, according to data from the United States Environmental Protection Agency, the number of operating landfills in the U.S. has dropped by more than half in the past ten years.
Although municipal incinerators are more environmentally friendly than they were a generation ago, they continue to release gases and solid particles that may harm human health, damage property, and kill plants. The biggest components of all municipal solid waste are compostable; yard waste, corrugated boxes, and food waste.
The benefits of composting have long been known. Though not a fertilizer, it is a useful soil conditioner that improves texture, air circulation, and drainage. Compost moderates soil temperature, enhances nutrient and water-holding capacity, decreases erosion, inhibits weed growth, and suppresses some plant pathogens. High quality compost is being used for and marketed as a soil amendment and as mulch for landscaping, farming, horticulture, and home gardens. Compost can also be used as landfill cover or in land reclamation projects.
There is a large body of art relating to in-vessel composting, some providing useful descriptions of the basic biological process. Existing in-vessel composters typically have one or more of the following general short-comings. (1) the system is too complex and the cost to purchase and operate is cost prohibitive to small businesses and organizations, (2) the system requires an extended processing time of generally greater than three weeks, such that the necessary capacity of the system becomes cumbersome and/or restrictive, or (3) the process produces output material which is less than 60% composted when removed from the vessel, requiring additional composting and processing time prior to curing.
There remains a need for an affordable, simple to operate, energy efficient, in-vessel composting system that substantially reduces the volume and weight of the input materials, and processes a useful end product of commercial value.
SUMMARY OF THE INVENTION
Disease-suppressive compost is not made by accident. It comes about by carefully monitoring the atmosphere inside of a composting vessel to ensure that the temperature, moisture, and oxygen levels are all maintained at proper levels throughout the entire process. Varying species of bacteria present in the composting vessel will break down and organic materials into the output compost mixture. And, as temperatures rise and fall in the compost, different bacterial species will become more or less active. Psychrophilic bacteria, mosophilic bacteria and thermophilic bacteria each operate best within specific temperature ranges. Furthermore, with sufficient oxygen, microorganisms produce energy, grow quickly, consume more material and make nutrients available for plant growth. Without oxygen, aerobic bacteria die off and anaerobic bacteria take over. They will break down the material, but more slowly, and with an accompanying unpleasant odor. Offensive odors are produced only when the material in the system is allowed to become anaerobic, not a normal condition in the practice of this invention.
To provide a simple, reliable, efficient, in-vessel composting system, it is most useful to optimize the apparatus to a selected, well-defined waste stream, thus reducing the processing variables and simplifying the apparatus and operation. This technique offers the user a composting process and apparatus that produces a more consistent, higher quality, nutrient rich, end product.
The invention, in it's simplest form, is an integrated or unitized reduction and composting process and system for the recycling of food waste and associated organic waste materials such as cardboard and paper board packaging materials, into a nutrient-rich liquid compost “tea” and bulk organic end product that are manageable, useful, and inoffensive. This waste stream provides an abundance of nitrogen and moisture, both important in the process. The amount of carbon and moisture absorbing bulk input can be varied, based on process conditions, by adding supplemental organic materials such as cardboard and paper board. The invention will accept traditional bulking agents such as sawdust and wood chips if desired, but is specifically designed to shred corrugated cardboard, found in many waste streams such as that of restaurants and supermarkets, to optimum size for the composting process of the invention.
The system is tolerant of a limited amount of incompatible solid contaminants that may be present in particular applications or installations. The invention utilizes a continuous four-step process which has approximately a three week throughput cycle, consisting of shredding to the optimal particle size, then mixing and composting the bulk materials through a three step, in-vessel process, while draining the excess liquid at the first stage and reprocessing it into compost tea through the finished bulk product. The apparatus is self-contained to provide for continuous input of raw waste, generating a bulk output of nutrient-rich, organic liquid and bulk compost materials of significantly less total volume and weight than the input materials.
Particle size is an important aspect of the composting process. If the waste particles are too large, the relatively small ratio of surface area to mass inhibits the start of the process. Shredding the material at the point of input offers a large advantage in this respect. On the other hand, if the input material is shred too small, porosity and the ability of the material to be aerated is greatly diminished. As a result, bacteria is less able to act. For the waste stream to which this invention is directed, an optimal particle size has been determined to be about 3 cubic inches. A shredder in the infeed stage provides for this requirement.
After the shredder sizes the input material, the material is directed into the first chamber of a three-chambered rotating drum. While three different drums would offer some flexibility in the control of the process, one drum and drum drive provides efficiency in the design that is reflected in cost and simplicity. A drainage mechanism in the first chamber diverts excess liquid into a batched, bypass system for later processing through the finished bulk compost product into compost tea. The drum and liquid handling systems are encased in an insulated enclosure, assuring that there will always be a surplus of heat. The apparatus is arranged on a base frame with the drum oriented horizontal, again contributing to simplicity.
Periodic and temperature-based drum r
Asmus Scott J.
Maine Vernon C.
Redding David A.
LandOfFree
In-vessel composting process and apparatus does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with In-vessel composting process and apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and In-vessel composting process and apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2861369