We have provided some useful information for you to understand the various issues involved in treating sewage. The information provided here is brief. For more detailed technical literature and drawings regarding applications, installation, maintenance or specific options, please contact us. We have both internal and field sales staff who will be pleased to assist.

Prior to installation, there is a legal requirement to obtain a Consent to Discharge from the appropriate agency. We offer full assistance in this respect.

Sewage is the wastewater generated from various utilities in our homes and includes kitchen, laundry and bathroom sink, as well as what you flush down the toilet. It is essentially 99.7% water containing solids like food particles, oils, dirt and chemicals like detergents 0.03%. Dirty water from businesses and factories is also discharged into the Sewage Treatment system. This is known as trade waste. Most of the sewage from our homes and businesses flows via large underground sewer pipes to Sewage Treatment Plants, where it is treated to make it safe for release back into the environment.

Sewage usually carries pathogenic organisms that can transmit diseases to humans and other animals; contain organic matter that cause odor and nuisance problems; hold nutrients that may cause eutrophication of receiving water bodies; and can lead to eco-toxicity. Proper collection and safe, nuisance-free disposal of the liquid wastes of a community are legally recognized as a necessity in an urbanized, industrialized society. The reality is, however, that around 90% of wastewater produced globally remains untreated, causing widespread water pollution, especially in low-income countries.

Increasingly, agriculture is using untreated wastewater for irrigation. Cities provide lucrative markets for fresh farm produce. Agriculture has to compete for increasingly scarce water resources with industry and municipal users. Often there is no alternative for farmers but to use water polluted with urban waste, including sewage, directly to water their crops. There can be significant health hazards related to using water loaded with pathogens in this way, especially if people eat raw vegetables that have been irrigated and grown with polluted water / sewage.

Request a quote for your sewage treatment plant today. Indus offers best sewage treatment systems at low cost.

Per person / activity / day (unless otherwise specified)

Explanation for Domestic housing sewage generation
A treatment system for a single house with up to and including 3 bedrooms shall be designed for a minimum population (P) of 5 people.

The size of a treatment system for a single house with more than 3 bedrooms shall be designed by adding 1 P for each additional bedroom to the minimum single house value of 5 P, eg:

• House with 3 bedrooms = minimum 5 P systemhouse with 4 bedrooms = minimum 6 P system (5+1)

• House with 6 bedrooms = minimum 8 P system (5+3)

For groups of small 1 and 2 bedroom houses or flats

• Flat with 1 bedroom = allow 3 P

• Flat with 2 bedrooms = allow 4 P

A treatment system serving a group of houses shall be designed by adding together the P values for each house calculated independently, eg:

• For a group of two houses (3 and 4 bedrooms, respectively) the system shall be for a minimum of 11 P (5+6)

If the calculated total P for a group of houses exceeds 12 P then some reduction may be made to allow for the balancing effects on daily flow of a group of houses (round UP not down)

• Where the total is 13-25 P multiply the total by 0.9 to give an adjusted P value, e.g. if there are four four-bedroom houses the total P will be     24 P (4 x 6) and the adjusted P will be 22 P (24 x 0.9 = 21.6)

• Where the total is 26-50 P multiply the total by 0.8 to give an adjusted P value, e.g. if there are four three-bedroom houses and three four-       bedroom houses the total P will be 38 P (4 x 5 and 3 x 6) and the adjusted P will be 31 P (38 x 0.8 = 30.4)

Mains & Off-Mains Drainage

Houses are linked to a public sewer pipeline – You flush the toilet, water goes into municipal sewers / drains and have very little to worry about. This is Mains Drainage. In suburban and rural areas many homes are self-contained; there are no municipal underground drains to carry Sewage Treatment Plant ( STP)

. This has no connection to the public sewer system and is known as Off-Mains. 1) Users have to make their own arrangement to dispose Sewage Treatment Plant (STP)

On-site: Critical Factors to Consider

As the flow chart below shows, site assessment is a vital stage in the system selection process. A septic tank installation in unfavorable conditions is likely to result in failure and expense. To minimize assessment costs, particularly for sites which prove unsuitable, Indus recommends a 3 step STP procedure.

Step 1: Consultation & Visual Inspection

• Make an initial visual assessment of the land’s suitability for septic tank drainage:

• Consult the Environmental Regulator

• The drainage field should be sited on land sloping away from the property.

• There should be adequate access for de-sludging vehicles.

• Any stream, well, borehole or spring on-site can affect the positioning of the unit.

• The site area and proximity of the site boundaries will help determine whether an adequate Sewage Treatment Plant (STP) drainage field can   be installed.

• Water loving plant species could indicate poor STP drainage.

Step 2: The Trial Hole

(Proceed with step 2 only if step 1 results are favorable)

• Well drained soil is usually brown, reddish or yellow. Grey or blue subsoil often means heavy clay or poor drainage.

• The position of the water table must not rise to within 1 mtr of the Effluent Treatment plant
distribution trench.

• There should be at least 0.5 metre of suitable subsoil available below the base of the distribution trench.

Step 3 – Percolation Testing

(Proceed with step 3 only if step 2 results are favorable)
Now that results of Steps 1 & 2 are favorable, it is essential that you carry out a percolation test in accordance with BS 6297 and building regulations. The percolation test will indicate soil porosity values. Excessively rapid percolation can threaten groundwater resources, whilst very slow percolation can result in surface water logging. Percolation test results will help you decide on the area of land needed to provide a sustainable drainage field. Conclusions In the site shown, the left hand soil profile shows:

• A low water table

• Suitable subsoil

• Advantageous topography

• Good access

• Adequate land area

These indicators, when combined with satisfactory percolation, would all suggest that a septic tank system may be sustainable. On the right side of the site a high water table, shallow subsoil and heavy clay suggest that percolation testing results will be unsatisfactory and an alternative disposal system should be installed. Indus will provide further advice.

Types Of Waste Water Treatment Plant – Aerobic & Anaerobic

Aerobic, as the title suggests, means in the presence of air (oxygen); while anaerobic means in the absence of air (oxygen). These two terms are directly related to the type of bacteria or microorganisms that are involved in the degradation of organic impurities in a given wastewater and the operating conditions of the bioreactor. Therefore, aerobic Waste Water Treatment Plant processes take place in the presence of air and utilize those microorganisms (also called aerobes), which use molecular/free oxygen to assimilate organic impurities i.e. convert them in to carbon dioxide, water and biomass. The anaerobic treatment processes, on other hand take place in the absence of air (and thus molecular/free oxygen) by those microorganisms (also called anaerobes) which do not require air (molecular/free oxygen) to assimilate organic impurities. 1) The final products of organic assimilation in anaerobic Waste Water Treatment Plant are methane and carbon dioxide gas and biomass.

From the summary in Table 1, it can be concluded that it is not anaerobic or aerobic Waste Water Treatment Plant, but a combination of the two types of the technologies that give an optimum 3) Configuration for those Waste Water Treatment Plant applications where the organic impurities are at a relatively higher concentration.
• We are the best waste water treatment plant manufacturers in India.

• We also offers waste water treatment equipment at reasonable cost

Aerobic Biological Treatment of Sewage can further be categorized into Suspended Growth and Attached Growth.

In suspended growth, bacteria remains in suspension in water and grows. It also attaches to the bottom and side wall of the aeration tank. This limits the growth of bacteria. Extended aeration is one of the popular and most widely used Suspended Growth processes.

Attached growth is a more modern development wherein various plastic media are submerged in sewage within the aeration tank so that bacteria will attach and grow much faster. Submerged Aerated Filter (SAF), Submerged Aerated Fixed Film (SAFF), Rotating Biological Contact Filter (RBC) are some of the variants of this Attached Growth process. While this helped the growth of bacteria, it also resulted in troubles like excess growth of bacteria on the media surface requiring media cleaning and was obstructing air flow within the aeration tank.

These twin problems were solved by the modern process called “Moving Bed Bio Reactor (MBBR)”. In MBBR circular plastic media (usually 22 mm dia) is introduced into aeration tank. This media provides huge surface area for bacterial growth. Typical surface area is about 350 to 400 square meters for each cubic meter of media. This media has gears on outer surface which forces its rotation in aeration tank due to the aeration from tank bottom. This helps the dislodging of dead bacteria while providing sufficient air to live bacteria.

A toilet is not a rubbish bin.What goes in your toilet, and down your sinks and drains, will affect the environment. Even though sewage is treated, some household items that get into sewerage system can still end up in rivers and the ocean. Often municipal sewers get chocked due to the rubbish thrown in to toilets. You can help protect the environment by considering the items that shouldn’t go down the sink or toilet.