ENVIRONMENTAL ENGINEERING

Dry Weather Flow

Dry weather flow

the flow through sewers available during non-rainfall period. It consists of domestic sewage and waste water sewage.

Storm water flow

the additional flow occurring during the rainy season. It consists of runoff from roofs, streets or open spaces during rainfall.

Dry weather flow

the quantity of wastewater that flows through a sewer in dry weather when no storm water is present in the sewer.

it is also called as sanitary sewage

80%

The quantity of waste water is assumed to be ____% of the quantity of water supply when no extra water enters the sewer.

150 L

ewer is an underground carriage system that takes impure water from houses and commercial buildings through pipes to treatment units and they should be designed for a minimum of ____ litres of waste water per capita per day.

200

The size of the town is 15,000. What is the density of population per hectare

30 years

The main and branch sewer is designed for the population that may occur at the end of one generation of ___ years. This period of ___ years is called a design period.

Infiltration

the process in which ground water unfiltrate into the sewers. It increases the load on the treatment work.

Exfiltration

is the process which indicates the flow of waste water from the sewer into the ground.

0.2-0.28m³/hectare/day

The rate of infiltration is expressed as litres per hectare of area per day. The rate of infiltration lies in the range of ______