Organic Waste Treatment Techniques

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Questions and Answers

What is the primary use of biogas produced from anaerobic digestion of sludge in large wastewater treatment stations?

Fuel for boilers and internal combustion engines

What are the three main types of organic materials used to produce ethanol?

Sugarcane and molasses, cassava, corn and potato, and wood or agricultural residues

What is the calorific value of ethanol?

7.13 kcal/g or 29.26 kJoule/g

What is the primary use of micro-algal production in aquacultural reuses?

Production of single-cell protein Signup and view all the answers

What percentage of protein is contained in algal cells produced during wastewater treatment?

About 50% Signup and view all the answers

What are aquatic macrophytes used for after harvesting?

As animal feed supplements or in producing compost fertilizer Signup and view all the answers

What are chitin and chitosan isolated from?

Shells of crustaceans, such as shrimps and crabs Signup and view all the answers

What are some of the applications of chitin and chitosan?

Wastewater treatment, food additives, disinfectants, and soil conditioners Signup and view all the answers

What is the primary component of municipal solid waste in low- and middle-income settings?

Organic waste Signup and view all the answers

What is the environmental impact of methane generated from illegal and uncontrolled disposal of solid waste?

Contributes to global heating, 87 times more than CO2 Signup and view all the answers

What is the result of biowaste attracting animals and disease vectors?

Puts human health at risk Signup and view all the answers

What are the three factors that influence the feasibility of an organic waste treatment approach?

Technical feasibility, economic feasibility, and social impact Signup and view all the answers

What is the primary benefit of recycling bio-waste?

Contributes to economic and environmental sustainability Signup and view all the answers

What is the result of anaerobic biowaste degradation?

Generation of methane Signup and view all the answers

Why is biowaste treatment important?

To prevent environmental and health risks Signup and view all the answers

What is the equivalent global warming potential of one kilogram of food waste disposed of in dumpsites and landfills?

Burning one liter of petrol Signup and view all the answers

What is the main objective of organic waste treatment?

To treat the wastes and reclaim valuable substances present in the wastes for possible reuses. Signup and view all the answers

What is the highest temperature that can be reached in the centre of the windrows during windrow composting?

70°C Signup and view all the answers

What is the main difference between in-vessel composting and windrow composting?

In-vessel composting uses rotating vessels instead of windrows. Signup and view all the answers

What is the role of earthworms in vermicomposting?

They feed on the waste and generate earthworm castings. Signup and view all the answers

What are the three products generated by slow pyrolysis?

Solid (char), liquid (bio-oil), and gaseous products Signup and view all the answers

What is the range of temperatures required for slow pyrolysis?

300-600°C Signup and view all the answers

What is the name of the emerging technology that involves the use of flies for organic waste treatment?

Black Soldier Fly (BSF) processing Signup and view all the answers

What is the first step in the vermicomposting process?

Aerobic degradation of organic matter by microbial communities Signup and view all the answers

What is the main difference between a rapid thermophilic digester and a normal biodigester?

A rapid thermophilic digester works six to ten times faster than a normal biodigester. Signup and view all the answers

What is the temperature range maintained in a thermophilic digester?

55-65°C Signup and view all the answers

What is the product of rapid thermophilic digestion that can be used on soil?

biofertilizer Signup and view all the answers

What is the most common application of thermophilic aerobic digestion?

treatment of sewage sludges in the wastewater industry Signup and view all the answers

What is the benefit of using enzymes over chemical catalysts in wastewater treatment?

reduces the formation of by-products and significant energy inputs Signup and view all the answers

What is the advantage of using immobilized enzymes in organic waste recycling?

degradation activity even under non-ideal environments Signup and view all the answers

What is an example of an enzyme that can be used to produce biodiesel?

esterases Signup and view all the answers

What is the benefit of integrating various waste treatment technologies?

optimum use of resources Signup and view all the answers

What are chitin and chitosan used for?

Components in manufacturing of cosmetic and medicinal products Signup and view all the answers

What is the self-purification process in wastewater?

Microbial activities decomposing and stabilizing organic compounds Signup and view all the answers

What is the purpose of injecting wastewater into wells?

To produce good quality water through filtration and microbial activities Signup and view all the answers

What is one of the most common ways of organic waste recycling?

Giving agricultural and food waste to animals as food Signup and view all the answers

What are the advantages of recycling food through animal feed?

Reduced pressure on landfills, reduced methane production, and no need to convert waste Signup and view all the answers

What is the purpose of rendering?

Converting waste animal tissues into stable and usable forms Signup and view all the answers

What is the process of rendering?

Exposing waste animal tissues to high temperature and pressure to destroy pathogens Signup and view all the answers

What are the products of rendering used for?

Solid particles used in pet food, and fat used in soap making Signup and view all the answers

Study Notes

Organic Waste Treatment Techniques

Organic waste, also known as biowaste, makes up a significant fraction of municipal solid waste in low- and middle-income settings, often exceeding 60% of total waste.
Improper disposal of organic waste leads to methane generation, which has a significant impact on global warming, with methane's contribution to global warming being 87 times higher than CO2 in the near term.

Factors Influencing Feasibility of Organic Waste Treatment Approaches

Technical feasibility: considers land area, skills, and capacity required to implement and operate the technology, as well as waste feedstock quantity and quality.
Economic feasibility: includes capital and operational costs, revenue streams from product sales, and job creation.
Social impact: considers health threats, job creation, and other social aspects of the technology.

Importance of Bio-Waste Treatment

Bio-waste naturally degrades through biological activity, which may occur aerobically or anaerobically.
Proper treatment of bio-waste is crucial to reclaim valuable substances, including carbon, nitrogen, phosphorus, and other trace elements.

Examples of Bio-Waste Treatment Technologies

Windrow composting: biodegradable waste is piled up in long heaps, reaching temperatures of up to 70°C, contributing to pathogen and weed seed elimination.
In-vessel composting (and bin-composting): uses rotating vessels to accelerate the composting process, improving aeration.
Vermicomposting: uses microorganisms and earthworms to degrade organic matter, generating earthworm castings.
Slow pyrolysis: decomposes organic material at high temperatures (300-600°C) in the absence of oxygen, producing solid, liquid, and gaseous products.
Black Soldier Fly processing: uses black soldier fly larvae to break down organic waste, generating valuable products.
Aquacultural reuses: involves the production of micro-algae, aquatic macrophytes, and fish using organic waste.
Indirect reuse of wastewater: wastewater can be discharged into rivers or streams, allowing for self-purification through microbial activities.
Animal feed: agricultural and food waste can be fed to animals as a simple and efficient method of waste recycling.
Rendering: converts waste animal tissues into stable and usable forms like feed protein.
Rapid thermophilic digestion: rapidly ferments organic waste using microorganisms at high temperatures, producing a biofertilizer.
Immobilized enzyme reaction: uses enzymes to degrade organic waste, allowing for important modifications like oxidation, hydrolysis, and phosphorylation.

Integrated and Alternative Technologies

The integration of various waste treatment technologies can be implemented to optimize resource use, with the waste of one process serving as raw material for another.

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Description

Learn about organic waste, also known as biowaste, and its treatment techniques. Discover how illegal disposal of biowaste contributes to methane emissions and global heating.