Primary Biological Processes
There are two key interlinked biological processes our core bionomicTM wastewater technologies provide optimized controlled habitat for: Anaerobic digestion and subsequent water rehabilitation by micro-algae. In order to put these into perspective, let us first look at the basics how nature deals with ‘organic waste’.
Once nature has identified ‘organic wastes’ – probably better defined as “organic dead matter” – microbes go to task on digesting and disassembling the material into its constituents. There are aerobic, anaerobic as well as some ‘in-between’ microbes that participate. The microbial colony mix depends largely on the origin and location of the matter. In the cycle of life it is these microbes responsibility to make sure that nutrients and building blocks are recovered and made available to the next life-cycle organism in line. Indigestible materials become part of soil structures while nutrients are mineralized for uptake.
When nature deals with water bound organic dead materials, things are only slightly different. Dead matter is ‘shredded’ by multicellular organisms and other mechanics with the resulting materials then processed by mostly anaerobic microbes into their basic components. Indigestibles eventually find their way to the bottom of some body of water while nutrients are mineralized and flushed along for uptake by the next organism in line – typically a photosynthetic organism that uses those nutrients to build biomass.
The first part of this process – the decomposition and digestion is commonly referred to as anaerobic digestion. Anaerobic digestion resulting in biogas and mineralized fertilizer is the result of a very complex symbiotic working relationship between several microbial colonies. The interplay between these colonies are shown in simplified form in the graphic on the right.
Theoretical biogas yields can be calculated in accordance with the stoichiometric formula below, which covers pretty much all unadulterated organic materials in our food chain.
A primary output of anaerobic digestion is CH4 – methane – which we know under the name: “Natural Gas.” Since the microbes also produce a certain amount of CO2, the produced gas is commonly referred to as biogas. We can use this gas for energy generation in a combined heat and power plant – also known as C.H.P..
Considering that all organic materials in our food chain can be defined in terms of carbohydrates, lipids and proteins, we can further qualify and calculate theoretical yields based on those three ‘food groups’
Actual biogas yield depends on a multitude of factors but in summary form and for general guidance, practical yield potentials can be expressed in terms of liters of biogas produced per kg of dry organic matter ‘digested’ at a certain temperature profile over time.
Based on the stoichiometry and the actual tabulated average gas yields, we can fairly quickly and reasonably estimate biogas energy potentials for virtually any organic source or substrate. – including organically laden wastewater. Since we are using the biogas for energy generation and are oxidizing the CH4 to CO2, we can also estimate our direct GHG mitigation potential.
Our optimized anaerobic digester cascade with a multistage proprietary reactor does not have any moving parts to minimize energy requirements and provides optimum habitat without cross-flows to make sure that maximum decomposition and optimum biogas production is achieved, while nutrients are mineralized for downstream availability to the next stage – rehabilitation by micro-algae.
Water Rehabilitation by Micro-Algae
In nature, once organic materials have been digested and nutrients mineralized, micro-algae are the first ‘takers’ of the nutrients to produce biomass in direct proportion to the nutrients available.
The output from our anaerobic cascade is a clarified nutrient solution, which provides an ideal growth medium for micro-algae. Our reactor technologies provide optimized habitat for algae to make best use of dissolved nutrients and the CO2 from the flue gas of our biogas based energy generation by C.H.P.
Micro-algae can be incredibly fast ‘assimilators’ of nutrients under the influence of correctly proportioned CO2, temperature and light. Our proprietary algorithm is designed to reduce and balance dissolved nutrients to healthy levels and oxygenate the water to between six and eight mg/l. The biomass produced by the algae, which we harvest, contains carbohydrates, lipids and proteins depending on original nutrient content and species of algae employed. Certain algae we can use are able to produce a relatively large amount of lipids to the tune of one barrel per 3000 cubic meters of water rehabilitated. In addition, approximately half a barrel of nutrient rich algae ‘cake’ consisting of carbohydrates and proteins is produced. The uses for the lipids are obvious and the balance – the algae cake – can be used as green fertilizer or , depending on chemical composition, as mineral feed supplement in aquaculture or livestock husbandry.