Kinds of water treatment:

Septic tank disposal systemsWater treatment plants

Innovative systems are being developed to reclaim wastewater waters so that they can be used to irrigate fields, parks or golf courses.

Some developers also say that rather than hiding the wastewater plants, they should come to expect sewage to be reclaimed at small cost producing flowers and shrubs in a park-like setting.

WASTEWATER TREATMENT

22 million systems in operationHalf a million new systems are added per

year30 percent of the people in the US use septic

systems

FACTS ABOUT SEPTIC TANK SEWAGE DISPOSAL SYSTEM

Geologic factors that can affect the suitability of a septic tank disposal system:

Type if soilDepth of the water tableDepth to bedrockTopography

Reasons why most septic tanks fail:Poor soil drainage

Stages of wastewater treatment:Primary treatment

Screening Sedimentation

Secondary treatment Activated sludge Disinfection of the wastewater

Advanced treatment Chemicals Sand filters or carbon filters

WASTEWATER TREATMENT PLANTS

A troublesome aspect of wastewater treatment is the handling and disposal of sludge.

The amount of sludge produced in the treatment process is conservatively estimated as about 54 to 112 grams per person per day, and sludge disposal accounts for 25 to 50 percent of the capital and operating cost of the treatment plant.

Sludge handling and disposal

To convert the organic matter to a relatively stable form

To reduce the volume of sludge by removing liquid

To destroy or control harmful organismsTo produce by-products whose use or sale

reduces cost of processing the sludge

Sludge handling and disposal objectives:

Final disposal of a sludge:

IncinerationBurying it in a landfillUsing it for soil reclamationDumping it in the ocean

The process of recycling liquid waste called the wastewater renovation and conservation cycle

WASTEWATER RENOVATION

WASTEWATER TREATMENT AS RESOURCE RECOVERY

Problems faced by this new technology in being more widely used:

We have a tremendous investment in more traditional wastewater treatment plants and are familiar with them.

There is a general lack of economic incentives to provide for new technologies

There is a general lack of personnel capable of designing, building and operating these systems. However, as more universities are developing true environmental engineering programs, this problem may be rectified