A farmer sends maize waste to a digester. Fig. 1 shows the sealed tank and a pipe carrying biogas to a small generator. Microorganisms break down the waste ...
Question 1 Report
A farmer sends maize waste to a digester. Fig. 1 shows the sealed tank and a pipe carrying biogas to a small generator. Microorganisms break down the waste without oxygen. Table 1 gives gas measurements over four days.
| day | biogas volume / dm3 |
|---|---|
| 1 | 12 |
| 2 | 21 |
| 3 | 25 |
| 4 | 24 |
(a) Name the main fuel gas in biogas. [1]
(b) Use Table 1 to give the day with the greatest biogas volume. [1]
(c) Suggest why the digester must be sealed. [1]
(d) Give two advantages of using this fuel rather than sending the maize waste to landfill. [2]
Answer Details
(a) The main fuel gas in biogas is methane [1].
(b) The greatest biogas volume, \(25\text{ dm}^3\), was measured on day 3 [1].
(c) The digester is sealed to keep oxygen out and maintain anaerobic conditions, or to prevent gas escaping [1].
(d) Two valid advantages are:
- It uses waste material [1].
- It produces a renewable fuel [1].
- It reduces the volume of waste sent to landfill [1].
- Methane can be captured rather than escaping to the atmosphere [1].
Any two of these points gain [2].
Download The App On Google Playstore
Everything you need to excel in your exams
