Ambergris Caye Belize Resort Development - Department of ...

5.0 Wastewater Disposal
5.1 Nature of Wastewater
Chapter 5
Wastewater is a combination of the liquid and water carried wastes from residents,
commercial buildings, industrial plants, and institutions, together with any ground water,
surface water and storm water that may be present. It is expected that the wastewater
generated by the project will be that of Domestic wastewater.
Domestic wastewater is the spent water originating from all aspects of human sanitary
water usage. It typically institutes a combination of flows from the kitchen, bathroom and
laundry, encompassing lavatories, toilets, baths, kitchen sinks, dishwashers, and washing
machines. Domestic wastewater as the name implies, principally originates in residences,
commercial and institutional establishments and is also referred to as sanitary sewage.
5.2 Wastewater Characteristics
Raw or untreated sewage is mostly pure water. In fact, sanitary wastewater comprises
about 99.9 % water and 0.1% impurities. Most of these impurities are biodegradable
organic material and pathogenic microorganism. Sea water on the other hand is only
about 96.5 % water and 3.5 % impurities. Although sea water has more impurities than
sanitary sewage, it’s not the concentration but the type of impurities that’s important. For
this reason wastewater is characterized in terms of its physical, chemical and biological
composition.
The expected characteristics of the wastewater produced by the project site will be that of
a typical domestic housing development as shown in table 5.1. Fresh, aerobic wastewater
has been said to have the odor of kerosene or freshly turned earth. Fresh sewage is
typically gray in color as well.
*Table 5.1 Typical Composition of untreated domestic sewage
Weak Medium Strong
Constituent (all mg/l, except for settleable solids)
Alkalinity (as CaC03) 50 100 200
BOD 100 200 300
COD 250 500 1000
Total Suspended Solids (TSS) 100 200 350
Settleable Solids 5 10 20
Total Dissolved Solids (TDS) 200 500 1000
Total Kjeldahl Nitrogen (TON) 20 40 80
Total Organic Carbon (TOC) 75 150 300
Total Phosphorus 5 10 20
* adapted from Davis-Cromwell: Introduction to Environmental Engineering, pp 353
5-1