Roman House, Sector No. 1, Plot No. 7 & 9, Chheda Nagar Road No. 4, Off. Service Road,

Chembur, Mumbai 400089

Monday to Saturday

10am to 7pm


Rainwater Harvesting

The rainwater that falls on the roof is pure, but since it comes in contact with various surfaces on its way to the storage units, some dust and leaves may get carried away with it. This can be reduced if the terrace is swept before the rains. However, even if some dust or leaves go into the sump, they do not cause any harm as long as the water is boiled before consumption.

Various filters can be utilised to remove such suspended pollutants from the rainwater collected to make it safer for consumption.

  • Catchment areas that include roofs of buildings and open spaces.
  • Storage units that can be a barrel, a tank or even a sump.

Conveyance mechanism which transports the water falling on the catchment area to the storage unit.

As per the law, you need to store or recharge 20 litres for every sq.m of roof area and 10 litres for every sq.m of non-roof (ground surfaces such as parking, backyard) area. This is for plot sizes of 40x60 sq.m or more. For e.g. if your home has about 100 sq.m of roof area, and about 50 sq.m of non-roof area, then you will need to create capacity for at least 2500 litresof water. If you are using a 1000 litre tank to store rainwater for immediate use, you can connect the overflow to a 4000 litre (3 feet x 20 feet) recharge well.

The benefits include:

  • Flood mitigation: Appropriately designed recharge structures in open public spaces, will help keep the roads from flooding. When water is not allowed to leave the premises, the chances of it choking up the roads are minimal.
  • Increasing groundwater levels: Marked improvement of both the quantity as well as the quality of the groundwater in areas which have implemented rainwater harvesting
  • Greater water availablity: Rainwater collected in storage tanks is available as and when needed
  • Prevents soil erosion and flooding especially in urban areas


  • Catchment areas that include roofs of buildings and open spaces.
  • Storage units that can be a barrel, a tank or even a sump.

Treatment of sewage is based on a method provided by nature, i.e by using microbial action. When a steady consistent supply of air is pumped into a tank containing sewage which has been screened to remove all floating debris and non soluble contents in sewage, microbes which are present in it get activated. These microbes are present in the sludge which makes up a substantial part of sewage, and they consume the pollutants in the sewage while the air supply brings them to life and keeps them alive and multiplying.

This is a time tested system called the world over as the 'Activated Sludge Process (ASP)'. It is the oldest system world wide and is the most used process world over. An STP based on this aerobic process will consist of the following major stages of treatment :

  • Primary Treatment: In this stage, raw sewage is screened to remove floating debris/ insoluble impurities such as plastic bags, leaves, twigs, paper,etc.
  • Secondary Treatment: In this stage, oxygen(air) is mixed into the sewage to activate the microbes which consume the pollution load and which then become sludge (biomass) . Aerated sewage and sludge are than separated so that the sludge can be removed and de-watered/ dried for disposal. The sludge can be used as compost in a garden. The water free from sludge is sent to a clear water tank(also called clarified water tank).
  • Tertiary Treatment: Clarified water is filtered through a pressure sand filter and an activated sand filter to remove any remaining suspended impurities and a substantial portion of the BOD & COD present in it. Finally it is disinfected to kill all the bacteria present in it by either chlorination or ozonation or with ultra violet light. This tertiary treated water is then pumped into a dedicated set of storage tanks from where it is used to flush toilets, wash roads, yards and for gardening.
  • A majority of the STPs in India are based on this ASP system in its most basic form. Such STPs are highly susceptible to input fluctuations (a frequent feature in India) and this results in a lot of untreated sewage and other related problems.

Other processes available :

  • A fairly recent system called the MBR system (membrane bio reactor system) which is a superior system is becoming very popular. It is a very compact waste treatment system that combines biological decomposition with membrane separation of the sludge (biomass).The membrane compacts & concentrates the sludge making for a far more compact design than the ASP system described above(it combines the secondary and tertiary treatment in one single step). Further it produces far less sludge too. Best of all ,it is not so sensitive to input load fluctuations like the ASP system.However, an MBR system requires skilled operators, though it can be automated to cut out operator error and poor operation.
  • DEWATS (Decentralised Water Treatment System) is a combination of anaerobic treatment with aerobic treatment. It is a low cost system and requires no operator intervention unlike the ASP. This process has no moving parts and it can even provide methane gas from the anaerobic part of the system which can be used for cooking. The DEWATS system was developed keeping in mind the needs of developing economies where it is difficult to get skilled operating personnel for conventional ASP based STPs. Treated water from DEWATS will still require tertiary treatment for re-use/recycle,and this part of the system (tertiary treatment) needs operators.

Reed Bed Sewage Treatment System is an extremely eco friendly system where sewage is allowed into a constructed water body where certain kinds of aquatic plants are planted which absorb atmospheric oxygen. and let this out through their roots thereby providing the oxygen to feed the microbes which will clean up the sewage. This system does however require a tertiary treatment system if the treated sewage is required for anything more than gardening. Its drawback is that it requires a lot of land to function and this is a major disadvantage in a world where space is at a premium. One major advantage is that it requires virtually no electricity to operate if the flow of raw and treated sewage is by gravity.

About four to six weeks from start up. You can accelerate this by seeding the unit with the sludge from an operational aerobic sewage treatment system.

Solar Plant

A: The size of the system is usually directly proportional to the amount of power you use. As part of the proposal process Sunlight Electric will perform a site assessment, analyze at least twelve months' worth of utility statements, and raise the question of near-term (3-5 year) expansion and business plans. With that information, taking into account the specifications and limitations of the components, Sunlight Electric will present recommendations for your input and feedback the goal of making sure you feel the ultimate path chosen is ideal.

It depends. Roof-mounted tends to be less expensive as they require no support structures and are most often not visible to passersby. On the other hand, ground-mounted systems can usually be oriented and tilted to optimize production. Through understanding your business and your needs, Sunlight Electric will present a solution that optimizes for your business and your needs.

A: Unlike the early days of solar power when systems had to be sized for peak loads, a grid-connected PV system seamlessly switches to draw from the utility grid when needed. As such, Sunlight Electric uses an annual production target, averaging out sunnier days with cloudy days.

A: Is back-up power critical to your business? For most businesses, the answer is “no” and if you don't have a back-up solution today, an ordinary grid-connected PV system will leave you in the same position. However, if you require back-up power or are looking to upgrade your business's disaster preparedness, Sunlight Electric can design a battery storage solution for your PV system to automatically switchover in the event of a power outage. Most customers inquire about batteries and ultimately choose to do without based on cost.

Stp/Grey Water Treatment

Do not store greywater! Learning to use greywater can feel counter-intuitive because the rules for irrigating with fresh water do not apply. You can store fresh water or rainwater for later use, but greywater should be used as soon as possible after it’s produced. In pumped systems with a temporary surge tank greywater should not stay in it for more than 24 hours. Unlike rainwater and fresh water, greywater has nutrients and organic matter from soaps and dirt. As these start to decompose they use up the oxygen in the water, which begins to smell very bad. It is possible to treat the greywater for storage, but this is impractical in most situations because fresh greywater is generated on a daily basis.

Dishwashers are not usually a good sources of greywater because the detergents for dishwashers are typically high in salt, which is harmful to plants and soils. If you are able to find a dishwasher detergent that does not have salt or boron in it, then the greywater can be reused. If you don’t have a sewer/septic option, and can’t find “plant friendly” detergents, direct greywater to a dedicated portion of the yard and plant with salt tolerant plants. If your state doesn’t consider kitchen water “greywater,” than a system using dishwater water will not be code compliant.

There are two main rules to follow to protect the environment.

  • Send nothing toxic down the drain.
  • Do not allow greywater to enter a fresh water source, like a creek, stream, or river, or high groundwater table. Biodegradable material will compost on the land, but will contaminate a creek. Nutrients will fertilize plants on land, but will cause algae to grow and rob water of oxygen, harming aquatic organisms.
  • Use biodegradable products that are salt and born free (which harm plants and the soil)
  • Vermi-Composting

    Vermi-composting is an aerobic process which means with oxygen. A properly managed worm bin will not have an offensive odour. If there is a bad odour, it is usually an indication of aerobic (lack of oxygen) conditions. Often this is the result of over feeding the worms. Having too much food in your worm bin can push the air out. Simply remove any large pieces of food that the worms haven't go to yet. Gently "fluff" the bedding to increase air circulation. A bad ordour may also occur if the worm bin is too wet.

    Fruit flies can be an annoying if not managed properly. Fruit flies are attracted to exposed fruit in a worm bin. The first defense against these critters is to make sure all food stuffs are buried under the bedding. The worms will eat the bedding, so if you are having a hard time burying you food simply add some more shredded paper on top.
If you already have a bad infestation, you can use a vacuum to suck up any flies (be sure to empty vacuum bag right away or the flies will make there way out again). Then remove the top inch or two of the bedding. This will get rid of any fruit fly eggs that have been deposited in you bin.

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