problem1. One very significant element of landfill design is management of gas emissions.

i) Mention the two main gases produced in a landfill and describe how they are produced.

ii) describe how landfill gas can be managed.

iii) Describe the potential environmental and health risks allocated with landfill gas and suggest some safety measures to be adopted by landfill workers in this respect.

problem2. Information about the properties of wastewater is significant in design of waste water treatment plant. These properties can be categorized as physical, biological and chemical. describe three physical, three chemical and three biological properties of the wastewater, describing their significance.

problem3. Describe why biological processes are preferred to physico-chemical processes for removal of nitrogen in waste water.

problem4. describe the impacts of discharging effluents having high nitrogen content in environment.