REP - Certified Renewable Energy Professional Bioenergy and Waste-to-Energy Questions and Answers

Question 1

A waste-to-energy facility is evaluating thermochemical conversion technologies for a feedstock primarily composed of mixed plastics and non-recyclable paper.
To maximize the production of a versatile, combustible gas mixture (syngas) that can be used to generate electricity in a gas engine, which of the following technologies would be most suitable?

Accepted Answer

Gasification

Answer

Anaerobic Digestion

Answer

Pyrolysis

Answer

Mass-Burn Incineration

Question 2

Which of the following is the correct sequence of the four primary stages in the anaerobic digestion process for biogas production?

Accepted Answer

Hydrolysis, Acidogenesis, Acetogenesis, Methanogenesis

Answer

Acidogenesis, Hydrolysis, Methanogenesis, Acetogenesis

Answer

Methanogenesis, Acetogenesis, Hydrolysis, Acidogenesis

Answer

Acetogenesis, Methanogenesis, Acidogenesis, Hydrolysis

Question 3

A renewable energy professional is assessing the environmental impact of a proposed mass-burn waste-to-energy incinerator. Which of the following is a primary environmental concern that requires significant investment in advanced pollution control systems for such a facility?

Accepted Answer

Formation and release of dioxins, furans, and heavy metals

Answer

High water consumption for cooling towers

Answer

Noise pollution from waste delivery trucks

Answer

Land degradation from ash disposal

Question 4

What is the key operational difference between pyrolysis and gasification in the context of waste-to-energy conversion?

Accepted Answer

Pyrolysis occurs in the complete absence of oxygen, while gasification uses a limited amount of oxygen.

Answer

Pyrolysis uses high pressure, while gasification operates at atmospheric pressure.

Answer

Pyrolysis is a biological process, whereas gasification is a chemical process.

Answer

Pyrolysis is exclusively for liquid biomass, while gasification is for solid biomass.

Question 5

A municipality is planning to generate energy from the organic fraction of its solid waste, which includes food scraps, yard trimmings, and wastewater sludge. They aim to produce a renewable natural gas (RNG) for injection into the local gas grid and a nutrient-rich soil amendment. Which bioenergy process is best suited for these goals?

Accepted Answer

Anaerobic Digestion

Answer

Refuse-Derived Fuel (RDF) combustion

Answer

Plasma Arc Gasification

Answer

Hydrothermal Liquefaction

Question 6

Which of the following is considered the primary rate-limiting step in the anaerobic digestion of fibrous or complex solid organic waste?

Accepted Answer

Hydrolysis

Answer

Methanogenesis

Answer

Acetogenesis

Answer

Acidogenesis