Fats, Oils and Greases, commonly known as FOG, are not broken down very well by anaerobic treatment. The FOG pre-treatment is an aerobic process which breaks the FOG down into materials which can be processed in the anaerobic digester.
Wastewater feedstocks such as various food processing wastewaters, municipal wastewater, and etc., often have very low (<2.5%) solids content with high liquid volumes resulting in very large digesters being necessary to treat them at the required HRT.
The feedstock concentrator allows us to cost effectively process feedstock streams which were previously much too costly to digest anaerobically due to their low solids contents and high volumes.
EXPLOSIVE CELL RUPTURE (ECR)
The ECR accepts particle size below 1mm and reduces particles to below 50 microns with the following benefits;
Feedstock particles are exploded which releases trapped organics or COD thereby increasing biogas yield while promoting biodegradation.
Feedstock is pasteurized and harmful pathogens such as salmonella and E.Coli are destroyed.
Feedstock is homogenized to create a consistent feedstock for microbial consumption.
Biogas can be produced from a broad range of feedstocks including organic waste materials and purpose developed feedstocks (i.e. Energy Crops). Feedstocks may be solids, slurries and either concentrated or dilute liquids. In fact, biogas can even be made from the left-over organic material from other bioenergy processes such as ethanol fermentation or biodiesel production.
The first step in our process is to get the feedstock into the correct form; the Pre-Treatment step. This step may involve one or more technologies to achieve the required form. The single most important goal is to reduce the particle sizes of the solids in the feedstock. This important as it enlarges the available specific surface over which biological reactions can occur, which has a knock-on effect on the process time and process efficiency.
Our feedstock pre-treatment systems break down the feedstock particle size to the point where communities of minute micro-organisms are able to easily digest the organic material which means that we can accelerate the time required for biological degradation and ensure very little if any organic material remains undigested. This is important for the rate of hydrolysis in anaerobic digestion (AD), where smaller particle sizes will result in a shorter retention time thus offering lower capital and operating costs.
Feedstock preparation can be a multistage process depending on the feedstock characteristics.
Large solids and inorganic material have to be removed and treated separately. Ligneous bedding material regularly occurring in animal manure is treated through enzyme hydrolysis while alkaline hydrolysis can be used to break down animal tissue.
Some feedstocks do not break down readily through the standard anaerobic process and hence need special treatment. Examples include; lignin (commonly found in animal bedding, spilt foods and woody biomass), some energy crops (purpose grown crops which usually contain between 5 and 20% ligno-cellulose), and feathers (a by-product of chicken abattoirs). The Enzyme Hydrolysis Pre-Treatment process breaks these tough organic substances down through a combination of heat and enzymatic actions.
The Alkaline Hydrolysis pre-treatment process is usually deployed at abattoirs to break down blood, animal carcases and bones through a catalysed thermo-chemical process which uses heat, water and a base catalyst to rapidly dissolve tissue. The end result is a liquid mixture of amino acids, small peptides, sugars, nutrients, soap and the mineral ash of the bones and teeth (calcium phosphate). Besides feedstock for the AD process, one can also recover tallow (saleable product) from this process.
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