What are the advantages and disadvantages of anaerobic digestion?
As wastewater is processed in wastewater treatment plant, organic sludge is produced; this sludge must be further treated before being disposed of. Primary settling tanks, which are used to remove settleable, particle solids, and secondary clarifiers (settling basins), which are used to remove surplus biomass production generated in secondary biological treatment units, both generate sludge.
Sludge disposal from wastewater treatment operations is a costly and time-consuming issue.
The following are some of the sludge disposal methods:
(1) Sludge volume reduction, mostly through the elimination of water, which accounts for 97–98% of the sludge;
(2) Reduction of the sludge's volatile (organic) content, which eliminates nuisance situations by lowering putrescibility and reduces health risks by lowering microbe levels; and
(3) The final disposition of the remnants.
Sludge digestion by aerobic bacteria
Aerobic sludge digestion is one method for reducing the organic content as well as the volume of sludge. Microorganisms can oxidise a considerable part of the organic materials in sludge to carbon dioxide and water under aerobic conditions. The method reduces the amount of solids in the air by around half.
Batch or continuous flow operations are possible with aerobic sludge digestion plants. Sludge is introduced to a reaction tank in batch operations while the contents are constantly aerated. The sludge’s are aerated for two to three weeks after the tank is filled, depending on the type of sludge. The sediments and liquids are separated after the aeration is turned off.Solids in the range of 2–45 percent are eliminated, and the clarified liquid supernatant is decanted and recycled to the wastewater treatment facility. An aeration tank is used in a continuous flow system, followed by a settling tank.
In the absence of sludge from primary treatment units, aerobic sludge digestion is typically used only for biological sludge’s from secondary treatment units. The most prevalent application is for the treatment of sludge’s that have been discarded by extended aeration systems (which is a modification of the activated sludge system). Because no external food source is present, the microbes must rely on their own cell contents for metabolic needs, a process known as endogenous respiration.The residual sludge is mineralized, with the remaining organic elements consisting of cell walls and other non-biodegradable cell fragments.
Anaerobic digestion's benefits and drawbacks
A: The following are some of the advantages:
(1) Ease of operation and maintenance;
(2) Reduced capital expenditures;
(3) In the supernatant, decreased levels of biochemical oxygen demand (BOD) and phosphorus;
(4) Less impact from disturbances such as harmful interferences or variations in loading and pH;
(5) There is less odour;
(7) A reduction in soluble grease and hexane;
(8) Increased value of sludge fertiliser;
(9) Retention times that are shorter; and
(10) A viable option for small wastewater treatment plants
B: The following are some of the disadvantages:
(1) Greater running expenses, particularly energy expenditures;
(2) Very temperature-sensitive
(3) There are no beneficial byproducts produced by anaerobic digestion, such as methane gas;
(4) The ability to dewater in order to reduce sludge volume;
(5) Less volatile solids decrease; and
(6) The economics of larger wastewater treatment plants are adverse.
What can Netsol Water provide?
Netsol Water is a significant water and wastewater treatment firm in India, offering WTP, WWTP, STP, and ETP manufacture, among other services. We've made it our mission to save the planet. The company creates equipment’s and is committed to providing practical solutions that help businesses flourish. We are committed to providing our valued customers with hands-on service, expert counselling, and training.\