AU1001201A

AU1001201A - Composting of sewerage sludge (bio-solids) and other organic materials

Info

Publication number: AU1001201A
Application number: AU10012/01A
Authority: AU
Inventors: Ronald Coles; Peter Robert Rolliston
Original assignee: Individual
Current assignee: Individual
Priority date: 2000-01-04
Filing date: 2001-01-04
Publication date: 2001-07-05

Description

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION STANDARD PATENT COMPOSTING OF SEWERAGE SLUDGE (BIO-SOLIDS) AND OTHER ORGANIC MATERIALS Oe O The following statement is a full description of this invention including the best method of performing it known to me a-d 99ET20EG BO DISE6110 0313d 6-b,:Bl O uer +,0 This invention relates to the composting of difficult and\or noxious materials such as sewage biosolids and other organic materials in commercial quantities.

The successful composting of these and other materials has presented many problems in the past all of which have defeated the purpose of composting as the resulting smells, run ofl pathogen production and high failure rate nullified any advantages gained. This invention controls the composting environment by firstly isolating the correct materials either in a mixture or by them self and in a prepared state and inside a vessel designed for that purpose. The essential needs of the composting process are monitored and provided from out side of that environment and so ensuring control of the process and of the biproducts of the process.

EQUIPMENT

COMPOSTING VESSEL.

A composting vessel is a large semi-sealable container such as a shipping container (figure A) to which the following has been added:- 1. air injection (item 1) 2. drainage (item 2) 3. overhead sprinklers (item 3) 4. test points (item 4) air outlets (item *eo 1. Air injection is carried out in pipes placed at approximately 150-200 centres running parallel to each other, so covering the floor of the vessel. A flat floor gives best results but other floor shapes can be used. The pipes run from a manifold or manifolds and are sealed at one end. Several holes approximately 3mm diameter are drilled into these pipes at approximately 250mm centres so that the air coming from the holes will go upwards into the material mass. The hole centres are best staggered so that an even blanket of air is being forced into and through the composting materials. Spacing of the pipes and the hole centres will be determined by the materials to be composted and the compressed air available, the vessel size and its shape.

2. A drainage point is installed at the lowest point so that excess fluid will run off and be collected. This liquid is re-introduced into the vessel evenly and from the top and so spreading the bacteria responsible for the composting process evenly throughout the material. Excess liquid is drained away and stored for use or disposal.

ECd 99CTOE06 80 W01SI-110d M3138 Gir:BT TO uer 3. Overhead sprinklers are installed around the top of the vessel so that the entire compost mass can be moistened evenly with either the run-off liquid or fresh water. These sprinklers are located over head inside the vessel and produce a fine even spray.

4. Test points are installed around the vessel so that probes can be introduced for temperature and ph testing. These can be as simple as a hole so that probes can be inserted or as involved as permanently installed sensors.

Air outlets are required on the top of the vessel so that the introduced air may pass through the compost mass and out of the vessel. This can be directed through a bio-filter or the like to remove odour ifit is excessive.

MIXER

The first part of the process requires the composting materials to be mixed (when required) with suitable organic matter or matters to bulk up the mixture so as to allow air and moisture to travel through that mixture aiding the composting process. A mixing machine is required to mix these materials at the correct ratios and consistency to achieve the best raw material blends for the process. Testing of mixtures is required to obtain the most suitable materials and ratios.

AERATOR

The mixed materials have to be made friable and porous before they are put into the composting vessel. This can be done by putting the blended mixture into a hammer mill or a high-speed slinger disc or belt, which can then load the material directly into the composting vessel (figure The action of the sudden acceleration caused by these machines fragmentizes the material particles and so separating them creating the desired Smaterial consistency.

METHOD

The materials are mixed at ratios and types suitable for the process and the material types, which can only be determined by testing. This mixing is done in a mixer (previously described) which can be carried out in batch or continuous and this can be done at any time. There is usually no advantage in mixing other than at the time of loading the composting vessel and it can in fact be detrimental if done too far ahead of loading. This is then fed through an aerator (previously described) which rips the fibres and particles apart to form a light porous and aerated material that is loaded directly into the composting vessel The vessel is then closed and the process begins. The very basis of this process is to be able to hold and adjust the moisture, air (oxygen) and temperature *levels within the composting vessel to give the best possible environment for the 99CT20ES 80 WDIS11-10N H313d G*,:al To uer *to 3 composting process and hence bacteria to work. The daily monitoring of the temperatures will show the condition of the process and the destruction of unwanted pathogens (around 50deg Temperatures of 70deg C can be obtained. Moisture levels are also taken daily and moisture is added by way of the sprinklers until the most advantageous levels are obtained. The run off collected from the drain is reintroduced to the compost mass also by the sprinklers so as to eliminate run off to hold and increase the composting bacteria in the system. Air is then forced through the compost mass at pressures as to oxygenate the mixture. Air volumes and duration's determined for the mass by batch testing. The introduced oxygen influences the process positively but care should be taken not to cool the mass by excessive airflow. The escaping air is not released directly to atmosphere if aromas are strong but piped into a bio-filter where all smells etc are neutralized and is then returned to atmosphere. The cycle of moisture levels, temperatures, air injection and testing continues until the composting temperatures fall indicating the completion of the process. The vessel is then unloaded and the process repeated with such cycles taking approximately two weeks. In a 20 foot shipping container approximately 15 tons plus of solids can be composted at each cycle and with control of the process and the product.

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Claims

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