Q.
a) Explain the following two (2) methods of disposing the collected rubbish:-
i) Open dumping
ii) Land filling (10 marks)
b) Using suitable diagrams, explain the underground sewerage systems for the combined and separate system. (15 marks)
(25 marks, 2011 Q7)
A.
(a) Disposing collected rubbish
(i) Open dumping. In most unregulated countries, open dumping is the most inexpensive way of rubbish disposal. Rubbish is left on open ground and it poses public health problems.
The definition of 'open dump' by U.S. Environmental Protection Agency is:
Open Dump
'An uncovered site used for disposal of waste without environmental controls.'
Abandoned piles of household garbage, bags of yard waste, appliances, old barrels, used tires, and demolition debris such as lumber, shingles, pipes and asbestos can threaten the health of humans, wildlife, and the environment. Known as open dumps, these sites can be found throughout Illinois -- heaped at the bottom of ravines, in empty lots and pastures, and along roadsides. An open dump is an illegal waste disposal site and should not be confused with a permitted municipal solid waste landfill or a recycling facility. If allowed to remain, open dumps often grow larger, and may attract dumping of both solid and hazardous wastes.
Open dumps pose the following health, safety, and environmental threats:
- Fire and explosion
- Inhalation of toxic gases
- Injury to children playing on or around the dump site
- Disease carried by mosquitoes, flies, and rodents
- Contamination of streams, rivers and lakes
- Contamination of soil and groundwater
- Contamination of drinking water
- Damage to plant and wildlife habitats
- Decrease in the quality of life to nearby residents and the local community
Open dumps create a public nuisance, divert land from more productive uses, and depress the value of surrounding land.
Open dumps are locations where illegally dumped, abandoned piles of waste and debris are left in noticeable quantities. Fines are a common punishment for a person caught dumping at an open dump. Open dumps are commonly found in forests, backyards and abandoned buildings. Open dumps are sometimes removed shortly after they are created, but most will persist for an indefinite period of time when the site is situated in the wilderness or in public space without adequate public services.
... a multi-family dumpsite of any size or content. Open dumping is illegal under the Resource Conservation and Recovery Act (RCRA). The hazards of open dumping can include the release of toxics and heavy metals to the air and water; the increased presence of disease vectors such as rodents and insects; and physical hazards such as hypodermic needles, poisonous gases, and/or piercing objects.
Ref:
Wikipedia search 'open dumping', available at
https://en.wikipedia.org/wiki/Illegal_dumping
(ii) Land filling.
Similar question was asked in 2015 Q6i
(b) Combined and Separate Sewerage System
Similar question was asked in
In short, the difference between combined sewer from separate sewer is the mixture of soil and waste pipes (human and kitchen waste) with storm pipe which drains the rain water.
Hence, the combined underground sewerage system is of higher risk of contamination when stormy drain overflow during heavy downpour. This is because the mixture of waste (including human waste) with the surface over run of water during rain fall can backflow during stormy seasons as the drainage cannot cope with the volume of water.
Ref:
Earlier posts.