Tutorial Week 8 (2019 ) - werwer PDF

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Environmental Engineering (300737EE) Tutorial 8 Week 8 (2019)

1. The composition of solid waste from a residential community is as follows:

Component Combustibles: Paper & cardboard Food wastes Garden trimmings Others (textiles, rubber, etc.) Non-combustibles: Metal Glass Ash

Wet weight, %

Density, kg/m3

Moisture content (%)

Energy value kJ/kg

35 15 10 10

85 350 200 300

7 70 60 10

16,300 5,000 6,500 15,000

10 10 10

500 160 450

3 2 8

0 0 0

Estimate (a) the moisture content, (b) the density, and (c) the energy content of this waste. 2. In a city suburb, a typical household is provided with a bin of 270 L. Survey showed that the discarded waste density (average) is 100 kg/m 3. In this particular suburb it takes almost 3 hours to collect waste from all the houses in a single trip with the mean time to collect, dump and reach the next stop being 2 minutes. If a truck can compact the waste to a maximum density of 300 kg/m3 what can be its minimum volume?

V T=

V p× t a rt p

VT =volume of solid waste carried per trip by truck, m3 Vp = volume of solid waste per pickup or stop, m3/stop r = compaction ratio tp = mean time per collection stop + mean time to reach next stop, h ta = actual time spent on collection, h/trip 3. The following table indicates the projected end of year population and the respective waste generation rates. Assuming that the final compacted density of the waste in the landfill is 670 kg/m3, estimate the daily, and yearly volume of solid waste. It is expected to use a waste to cover ratio of 5:1. What volume of landfill is required for this scenario? If the total height of the landfill is expected to be no more than 10 m, estimate the required land area. Useful equation: Volume of landfill =

=

PEC Dc

P = population C = quantity of waste kg/capita.year

Dc = compacted density of waste E = Waste to cover ratio = Vw  Vc Vw = Vw = volume of waste, m3 Vc = volume of cover, m3

Year

2020

Projected end of year population ( x 1000) 30

2.1

2021

32

2.0

2022

34

1.8

2023

36

1.7

2024

38

1.6

2025

40

1.5

2026

42

1.4

2027

44

1.3

2028

46

1.2

2029

48

1.1

2030

50

1

Waste quantities kg/cap.d

4. List ten most common hazardous substances that can be found in a typical household....