Why choose best anaerobic digestion equipment?
Anaerobic digestion has been instrumental in the transformation of wastewater treatment plants (WWTPs) into water resource recovery plants (WRRFs).
Biogas, a renewable, clean, and green energy source, is made from the by-product formerly known as "waste gas." Some plants have generated enough electricity to feed renewable natural gas (RNG) into a pipeline and/or transmit power back to the grid.
Starting the anaerobic digestion process in a tank with some primary and secondary sludge doesn't take much. To grow, break down sediments, and make biogas, the entering bacteria only need an oxygen-free, homogeneous, warm habitat for roughly 15-20 days. The tank must be COVERED, MIXED, and HEATED in order for this to happen.
Inefficiencies, process problems, and catastrophic breakdowns can all be avoided by choosing the proper sort of digester cover, mixer, and heating system, and then successfully using the equipment.
What is the best type of digester cover?
Many factors influence this decision, and each facility or project has its own set of motivations.
Primary digesters were traditionally combined, heated, kept at a constant volume, and covered with a fixed steel cover. Secondary digesters were neither mixed nor heated, and liquid level changes from biosolids dewatering and/or transport were accommodated by buoyant or gasholder coverings.
Storage, Containment, or Both for Biogas?
A digester cover may appear straightforward at first glance, a structure that rests atop (or in) a tank to keep biogas in and oxygen out. These steel or membrane structures are gastight and under pressure. Some designs include biogas storage, which can be used as renewable energy.To preserve the outer membrane structure and pressurise the biogas, dual membrane gasholder digester covers use high-strength, PVC-coated textiles and inflation fans. Separate from the digester, this technology can also be used for standalone biogas storage.
Choose the Best Digester Mixer by Mixing It Up!
Digester mixers have become safer, more effective and more reliable as mixing technology has improved and progressed.Experience and widely established digester mixer design rules of thumb play a big role in choosing the right mixer. Advanced methods, like as computational fluid dynamics (CFD), struggle to represent the intricate interactions of particles, grit, liquids, and gas found in digester sludge.
A design that works-
1: Mixing with a Draft Tube
Draft tube mixers are axial-flow pumps with a high flow rate and low head that are built specifically for digesters. They can be put through the cover or the side of the digester tank and are reversible so they can pump up or down. These versions come with a warranty and usually last ten years before bearings and seals need to be replaced. This can be done on-site, and the mixer can be up and running again in a matter of hours.
2: Mixing by Pump
Pump and nozzle or jet mixing is a straightforward method that works best for highly variable-level digesters (or holding tanks).
3: Mixing in Linear Motion
Linear motion mixers are a relatively recent mixing technique that has gained popularity as a low-energy, non-rotational alternative.
4: Mixing of gases
On digesters with a constant liquid level, the "bubble cannon" method (gas shot into a draught tube) can be useful.
Maintain optimum conditions by keeping it hot!
Effective heating, mixing, and feeding regimes can all help to keep the process running well. Heat exchangers are used in most anaerobic digesters to transmit heat from hot water to sludge without mixing the liquids. A boiler or a combined heat and power (CHP) engine heats the water. The latter, often known as cogeneration, uses biogas to generate renewable electricity.
Raw sludge is fed directly into the digester (as gradually and regularly as feasible), and heat is added by cycling the tank contents through a heat exchanger. To prevent the sludge from becoming too hot, which can hinder the biology or "bake" sludge onto the tube walls, flow and temperature must be considered.
When it comes to selecting and managing a digester, there are numerous variables to consider. Understanding the equipment can help you reach project-specific goals, handle operational needs, and keep your digesters operating effectively in the long run, whether you're working on a large biogas-to-energy upgrade, a bio-solids management project, or simply need to replace an old cover.
To deal with all such issues or install a wastewater or water treatment plant at your premise, call us!