Biomass engineering is generally considered to be the addition of micro-organisms to a system in order to improve the biological function of that system. The addition is often made to improve a biological waste water treatment plant, but may also be made to other biodegradation processes such as soil remediation or composting.
Biomass engineering is also referred to as bioaugmentation, biosupplementation, bacterial augmentation, bacterial supplementation, biomass augmentation and inoculum addition.
Micro-organisms include bacteria and are often referred to as microbes, bugs or cultures. Fungi are also micro-organisms and play an important role in biomass engineering.
What can Biomass Engineering Do?
Products for biomass engineering are available for a number of biological waste water treatment problems, including products for addition to:
They can also be used for degreasing sewers and for clearing oil spills
Specific uses of products in biological waste water treatment plants are detailed below:
Biological Start Up of Treatment Plants
Normally waste water treatment plants are inoculated with micro-organisms which are present in the waste water itself and in the air around the plant. Frequently sludge is introduced from a near-by plant or from a selected plant treating similar type of waste water.
Adding specific micro-organisms at relatively high concentrations can accelerate the start-up process by introducing bacteria which are capable of degrading the components of the waste water.
This type of application of the product is usually very successful and enables a quick, clean and relatively cost effective start-up to be achieved. When newly constructed plants are involved it is often the case that the construction company wish to complete the biological commissioning as a matter of urgency to obtain payment for the work.
Improving BOD and COD Removal
Products with a broad range of activity may help overall organic removal, as measured by the Biochemical Oxygen Demand (BOD) and the Chemical Oxygen Demand (COD). These products are often designed for certain industrial waste waters e.g. dairies, petrochemical refineries, chemical manufacturing etc.
Control of Bulking Sludge
The phenomenon of poorly settling activated sludge, usually due to the presence of high numbers of filamentous micro-organisms, is termed “bulking”. Bioaugmentation products containing bacteria able to out-compete, or in certain cases biologically suppress, filamentous bacteria can be of great assistance in curing bulking.
It is generally considered that the condition of bulking is a function of several selective pressures and that very often it is not possible to modify all of these selective pressures to counter the problem. In such cases biomass engineering may prove to be the only realistic option offering some form of control.
Odours are often associated with sulphate reducing bacteria (SRB’s) that produce hydrogen sulphide. Bioaugmentation products containing microbes able to convert hydrogen sulphide to sulphur may be used to resolve such problems.
Elimination of Foaming and Scum Formation
Foams and scum on the surface of aeration and settlement tanks, are not only unsightly but, may reduce oxygen transfer efficiencies, prevent cooling of high temperature effluents, prevent waste gases escaping to the atmosphere and can be indicative of poor treatment. The causative agents may also be filamentous organisms or chemicals. Bioaugmentation products may be used to counter either type of foaming. It is important to ascertain with cause, where possible, and target the product accordingly.
Nitrification is the oxidation of ammonia to nitrite and nitrate by autotrophic bacteria. This is a particularly sensitive biological process which can easily be inhibited or completely destroyed by toxic chemicals. Because the microbes which carry out the reactions are slow growing and temperature sensitive loss of nitrification may take many days to recover. The introduction of nitrifying cultures can be effective in reducing the time lag or in increasing the concentration of active bacteria to raise the level of nitrification.
Improving Degradation of Xenobiotics
Xenobiotics are compounds which are new to the environment and are often produced by the synthetic chemical industry. Because these man made compounds are not familiar to nature they are often difficult to degrade as few naturally occurring micro-organisms can deal with them. Cultures developed in the laboratory by exclusive feeding on these xenobiotics can be used to provide greater degradation capacity in waste water treatment plants.
Reducing Sludge Production Rates
The production of sludge can give rise to disposal problems. As a result the minimisation of sludge yield can be very important in waste water treatment. the use of bioaugmentation products containing micro-organisms with high respiration rates but relatively slow growth rates can be very effective in reducing the volume of sludge requiring removal from the treatment system.
Increasing Methane Production
When anaerobic digesters begin to fail, methane production falls. Bioaugmentation may be able to arrest this and is considered as a safe option for the sensitive anaerobic digestion process.
The accumulation of organic solids in holding tanks, facultative lagoons and balancing systems can be problematic. Use of micro-organisms which are able to digest the accumulated solids can be effective in breaking down the organic material and allowing it to be returned the aqueous phase where the rate of degradation is much faster.
The use of aggressive cleaning chemicals in food preparation areas, wash-rooms, etc., in the quest for hygiene, tends to make life pretty difficult for the bacteria that populate the septic tank. This may be overcome by reducing the excessive use of the cleaning chemicals and reviving the bacterial population by introducing products containing bacteria which have greater resistance to the chemicals.
Products containing micro-organisms able to produce lipase enzymes and surfactants can clear grease from drain lines sewers.