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Waste Stablinzation Ponds

Waste Stablinzation Ponds

Multi-cell WSP system comprises of three types of ponds Anaerobic  ponds Facultative ponds and Maturation ponds. Types of ponds Usually a WSP system comprises a single series of the aforementioned three ponds types or several such series in parallel. Anaerobic and facultative ponds are designed...
DESIGN CRITERIA OF AERATED LAGOON

DESIGN CRITERIA OF AERATED LAGOON

Detention Time The basis of design Of aerated lagoon can be hydraulic retention time (HRT) as well as the mean cell residence time or solids retention time (SRT). Typical design value of HRT as well as SRT (0c), for suspended growth aerated lagoon varies from about 3 to 6 days, while for...
ADVANTAGES AND DISADVANTAGES OF WSP SYSTEMS

ADVANTAGES AND DISADVANTAGES OF WSP SYSTEMS

Advantages of WSPs are Lagoon systems can be cost-effective to design and construct in areas where land is inexpensive. They use less energy than most waste water treatment methods. They are simple to operate and maintain and generally require only part-time stuff. They can handle intermittent use...
Maturation Ponds

Maturation Ponds

Maturation ponds (low-cost polishing ponds), which generally follow either the primary or secondary facultative pond, are primarily designed for tertiary treatment, i.e., the removal of pathogens, nutrients and possibly algae. They are very shallow (usually 0.9 – 1 m depth), to allow light...
TYPES OF SEWERS

TYPES OF SEWERS

Need for Alternate Types of Sewers Installation of conventional sewerage system is not possible in many situations due to the following reasons:  The per capita water supply (including the local and individual sources) to the population is less than the minimum requirement of water supply for the...
SEWERS DESIGN CRITERIA

SEWERS DESIGN CRITERIA

Depth of Flow The sewers are always designed for the partial flow conditions. The purpose of maintaining partial flow in sewers is to maintain an open channel flow condition and to provide space above surface of sewage for ventilation. Sewers may be designed to run for a depth of flow of d, which...
SELECTION OF PIPE MATERIALS

SELECTION OF PIPE MATERIALS

The following factors should be considered in the selection of pipe materials for sewers: Technical factors Length of pipes: Individual pipe lengths vary considerably across the range of pipe materials. Leaking pipe joints are common source of infiltration and so minimizing the number of joints...
CORROSION IN SEWERS

CORROSION IN SEWERS

Causes for Crown Corrosion Bacteria in the slime under flowing sewage convert sulphates in the sewage into sulphides. Sulphides in the liquid make their way to the surface of the sewage and released into the sewer atmosphere as hydrogen sulphide (H2S) gas. H2S gas in atmosphere makes contact with...
RAIN FALL

RAIN FALL

The intensity of rainfall is the rate at which the rain is falling and it is expressed in cm/hr. For example, during a particular event of rainfall occurred for 10 minutes the quantity of rainfall is 2 cm, then the intensity of rainfall of that rain event is 12 cm/hr. 5 cm/ hr intensity of rainfall...
ESTIMATION OF SEWAGE FLOW AND STORM RUNOFF

ESTIMATION OF SEWAGE FLOW AND STORM RUNOFF

SOURCES OF WASTEWATER The wastewater is generated from domestic, industrial and agricultural activities. From domestic sources the wastewaters are generated from toilet known as excreta or black water and from kitchen and bathroom as sullage or gray water. If excreta and sullage are mixed together...
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