Clean water and ecologically friendly industrial operations are more crucial than ever in the 21st century. As the human population in India grows exponentially, the requirement for proper drinking water and water management becomes a major topic in the city life of the country.
A facility or installation that is utilized to clean up polluted materials is referred to as a treatment plant. Additionally, these components might be solid, liquid, or semi-solid. Water purification is the primary purpose at these facilities, which consists of the removal of contaminants from untreated water to produce ingesting water that is pure enough for the most fundamental of its supposed uses, typically for human consumption or in water waste management.
India has the biggest number of people without access to clean water in the world—more than 163 million—despite having over 25% of its territory covered by water. India’s rural poor are very exposed to the impacts of severe weather events and climate change, which are also to blame for the pollution of water since 67% of the country’s population lives in rural regions and just 7% of those have access to clean water.
The population of the soon-to-be most populated nation in the world wastes almost 38,354 million litres of water per day, with an annual growth rate of 1.0%. Due to this massive water waste, approximately 70% of India’s water is polluted, affecting three out of every four Indians and contributing to 20% of the country’s disease burden.
Because untreated chemical compounds and pathogens in wastewater may impair the health of animals, plants, and birds that live in or near the water, wastewater and drinking water treatment have become a serious concern. It may harm people’s health by contaminating crops and drinking water. Treatment of wastewater is essential to maintaining the health of several diverse ecosystems. The wastewater treatment market is growing at a rapid rate in the country where the market was valued at USD 2100.00 million in the year 2021 and is expected to reach USD 4033.27 million by 2029, registering a CAGR of 8.50% during this forecast period.
Wastewater, properly treated, is a source of water for many purposes. Good wastewater treatment allows the maximum amount of water to be reused instead of going to waste.
Components & Working Process:
Based on their usage water treatment plants can be categorized into different kinds:
- Sewage Treatment Plant:
Wastewater is the water that originates from water used in domestic, agricultural, industrial as well as medical or transport activities.
Sewage often comprises a large amount of organic wastes, while it may also include inorganic pollutants. Before being disposed of, sewage water must be treated since, if permitted to enter water sources untreated, it has the potential to pollute the source in a very short period of time.The sewage treatment facility may also include household sewage or include industrial wastewater, depending on the size of the municipality or governing body of the area where it is situated.
- Bar Screening:
To avoid harming the facility’s pumps, valves, and other equipment, big objects must be removed from the influent.
The first process ensures the removal of large items from the influent to prevent damage to the facility’s pumps, valves and other equipment. The quality of the water is dictated by the Environmental Protection Agency(EPA) and the Clean Water Act. and wastewater facilities operate to specify permits by National Pollutant Discharge Elimination System.The expected standard, the Biochemical Oxygen Demand(BOD) of average wastewater effluent is 200 mg/L and the effluent after treatment is expected to be >30 mg/L.
The physical process of wastewater treatment begins with screening out large items that have found their way into the sewer system, and if not removed, can damage pumps and impede water flow. A bar screen is usually used to remove large items from the influent and ultimately taken to a landfill.
Grit removal by passing influent over or through a grit chamber.
To avoid harming pumps and equipment downstream, fine grit that enters the influent must be eliminated (or impact water flow). This grit has to be taken out of the grit chamber since it is too tiny to be filtered out. The heavier grit may sink to the chamber’s bottom thanks to different kinds of grit chambers (horizontal, aerated, or vortex), while the water and organic material go on to the next step in the process. Physically removing and discarding the grit from the chamber’s bottom.
- Primary Clarifier:
Initial separation of wastewater and solid organic materials.
Sludge or organic solids are pumped to a digestor or other location for processing, dried, and removal after they sink to the bottom of the tank. An essential sign of how well the clarifier is working is proper settling rates. The operator may alter the flow rate into the clarifier to change the settling rates and efficiency.Following grit removal, the influent enters massive main clarifiers, which separate out 25% to 50% of the influent’s solids. These sizable clarifiers (75 feet in diameter, 7.5 inches at the borders, and 10.5 feet in the centre, for instance) enable the cleaner influent to flow while allowing the heavier materials to drop to the bottom. A proper water flow is necessary for the primary clarification to be successful.The water quality downstream will suffer if the water flow is too rapid since the solids won’t have enough time to drop to the bottom. In the reverse scenario, the process upstream would be affected.
To promote the conversion of NH3 to NO3 and to give oxygen for bacteria to continue to multiply and develop, the air is pushed into the aeration tank or basin.Once converted to NO3, the bacteria remove/strip oxygen molecules from the nitrate molecules and the nitrogen (N) is given off as N2 gas.
The primary goal of wastewater treatment is to break down organic material by promoting and accelerating the natural activity of bacteria. The aeration tank is where it all starts. The aeration tank’s main purpose is to pump oxygen into the tank to promote the breakdown of any organic material (and the development of bacteria) and to guarantee that the process has adequate time. The tank may be aerated by pumping and diffusing air into it, or by vigorous agitation that aerates the water. The optimal circumstances are created throughout this phase to promote bacterial growth.Oxygen levels lower than 2 ppm will cause the bacteria to die off and reduce the plant’s effectiveness. Monitoring of dissolved oxygen is essential at this stage of the plant. Measurements of Ammonia and Nitrate are often used to assess how well bacteria convert NH3 to N2.Biochemical Oxygen Demand is the primary factor used to assess oxygen in wastewater treatment plants (BOD). BOD is a substitute
indication for the volume of organic material that is present and is used to assess how well organic material is broken down. To guarantee proper organic material decomposition, further tests are performed, including those that measure the pH, temperature, dissolved oxygen, total suspended particles, water flow rate, etc.
Ongoing and accurate monitoring is crucial to ensure the final required BOD.
- Secondary Clarifier:
To enable any leftover organic matter to settle out of treated water flow, treated wastewater is pushed through a secondary clarifier.
As the influent leaves the aeration process, it enters a secondary clarifier, where any extremely minute particles (or fines), as in the primary clarifier, drop to the bottom of the tank. These tiny particles, also known as activated sludge, are mostly made up of living bacteria. To boost the bacterial concentration, aid in their growth, and quicken the breakdown of organic material, some of this activated sludge is reintroduced to the aeration tank. The surplus gets thrown away.
The water, flowing through the secondary aeration clarifier must contain fewer pollutant materials and should be reaching towards the effluent specifications.
- Chlorination (Disinfection):
To eradicate any leftover germs in the contact chamber, chlorine is introduced in this step.
It is necessary to analyse the departing effluent for the presence or absence of bacteria and to disinfect the water since the aeration stage increases the concentration of bacteria. This makes sure that germs in quantities greater than those allowed won’t be discharged into the environment. The most prevalent and affordable kind of disinfection is chlorination, although ozone and UV disinfection are also gaining favour. Before releasing chlorine into the environment, it is crucial to evaluate the free-chlorine levels to make sure they are within permissible ranges.
- Water Analysis & Testing:
Testing of pH level, Ammonia, Nitrates, Phosphates, dissolved Oxygen and residual Chlorine levels, ensuring the less harmfulness of the water released.
Final testing is performed to confirm that the effluent exiting the plant complies with permit requirements, even though testing is ongoing throughout the wastewater treatment process to guarantee adequate water flow, clarity, and aeration. If a plant doesn’t comply with the permit discharge limits, the operator in charge may be fined and/or imprisoned.
- Proper Effluent Disposal:
Ensuring the proper disposal of the effluent.
Since the purified water cannot be combined with the source of drinking water, effective disposal is just as crucial to sewage management as good treatment of the water. Of the light of this, appropriate and vigilant disposal in water reservoirs is also a crucial operation.
Other Suitable Processes:
UV Disinfection: Ultraviolet lamps emit UV light which destroys the DNA of bacteria. This process is also used as a replacement for the chlorination process.
- Effluent Treatment Plants(ETPs): The majority of the time, industrial wastewater is cleaned at effluent treatment facilities. They deal with industrial effluent, which is the wastewater produced as a result of various companies. In industries where there is a high probability of significant chemical contamination in the effluent, ETPs are often helpful. Just like STPs, ETPs also involve various stages of water treatment like primary, secondary and tertiary treatment.In an effluent treatment plant, the entire treatment process is divided into two stages, primary and secondary.
- Primary Treatment: Wastewater is briefly stored during primary treatment in a setting tank where heavier particles sink to the bottom and lighter solids float to the top.Once settled, these materials are held back while the remaining liquid is discharged or moved through to the more rigorous secondary phase of wastewater treatment.
Additionally, these enormous tanks often include mechanical scrapers that continuously move the sludge that has accumulated at the bottom of the tank to a hopper where it is pumped to sludge treatment facilities.
- Secondary Treatment: Secondary wastewater treatment is more thorough than primary treatment and is intended to significantly reduce the biological component of the waste via aerobic biological processes.
By bringing common biodegradable pollutants down to acceptable levels, secondary wastewater treatment enables a safer discharge into the local ecosystem.
It’s done in one of three ways.
- Biofiltration: To guarantee that any extra sediment is removed from the wastewater, biofiltration employs sand filters, contact filters, or trickling filters.
- Aeration: A long procedure called aeration adds air to wastewater to raise the oxygen saturation level. The aeration procedure usually takes up to 30 hours, although it is quite efficient.
- Oxidation Ponds: This technique, which is often employed in warmer areas, takes advantage of natural water bodies like lagoons, enabling wastewater to travel through for a predetermined amount of time before being held for two to three weeks.
Importance of Water Treatment:
One of the most important natural resources on the earth is clean water, which is necessary for life. Given the ongoing droughts and water shortages in many parts of the globe, wastewater, which is essentially wasted water, is also a significant resource. However, wastewater must first undergo treatment since it includes a number of dangerous compounds and cannot just be dumped outside. Therefore, wastewater treatment is crucial to both protecting the environment from contaminants and restoring the water supply.
- Restoring The Water Supply: A worldwide drought map will show you that there is just not enough water in many parts of the planet. All communities, particularly those with limited water resources, need to make sure they have efficient water treatment systems in place so that treated water can always be recycled or added back to the water cycle.
- Protecting The Planet: Contaminants from both household and business usage may be found in wastewater. Wastewater contains bacteria and chemical substances that, if left untreated, may be harmful to the health of birds, plants, and animals that live in or close to water. It may harm people’s health by contaminating crops and drinking water. The treatment of wastewater is essential for maintaining the well-being of many ecosystems.
If properly handled, wastewater may serve as a supply of water for a variety of uses. The greatest quantity of water may be utilised instead of being wasted thanks to effective wastewater treatment.
There are four distinct plant sizes for wastewater treatment facilities. The size of plants may be indicated in the amount of treated water used each day while taking into consideration the equivalent population.
Depending on the size, destination and automation of the processing, the water treatment plants have been differentiated into four categories.
- Autonomous Water Treatment Plant
- Small Wastewater Treatment Plant
- Medium-Sized Wastewater Treatment Plant
- Large Wastewater Treatment Plant
The following diagram shows
The following table lists the most likely and typical collection of features for the many potential configurations:
Even though sewage water management and treatment must be one of the most important things to consider while operating and maintaining civic life, the sector nonetheless encounters some significant difficulties on a daily basis.
High levels of sludge generation and power usage are the major problems in the sector. The following are the major problems, faced by the sector:
- Huge Power Demand: Energy consumption is one of the largest expenses in operating a wastewater treatment plant. Wastewater treatment is estimated to consume 2-3% of a developed nation’s electrical power or approximately 60 TWh (terawatt hours) per year. In municipal wastewater treatment, the largest proportion of energy is used in biological treatment, generally in the range of 50-60% of plant usage.
This massive demand for power results in a significant quantity of energy, which further enables the facility to carry out its regular
- Frequent Power Outages: Wastewater treatment plants have the important job of filtering and cleaning wastewater from multiple
sources. Wastewater can include numerous contaminants. Therefore, it is important for the plant to be operational on a whole-day basis. However, the plants often experience power interruptions due to the daily need for electricity. Recent occurrences like the March ’22 coal shortfall have caused a power deficit in the nation, causing the grid’s capacity to fall short of the demand.
The most common disruption in a wastewater treatment system is losing electricity because of a power outage. When a wastewater plant loses power and filtration or purification systems require electricity to operate, the systems will cease to run unless there is a backup generator or alternative energy source.
Some of the plant’s systems may function normally during a power outage, but as the duration of the outage lengthens, issues might develop:
- Gravity Outlet Systems: A gravity outlet system allows water to flow out of the sewage treatment plant naturally. In the event of a power cut, the system will not back up( fill up with water ) because of the natural flow out of the tank. Therefore, it is not urgent if power fails, if the power outage becomes longer, water quality will slowly deteriorate as bacteria in the system will die off.
- Pumped Outlet System: Occasionally, a pump is required to raise the water out of the treatment facility. This occurs if the ditch or stream is at a higher elevation than the underground pipes. Because pumped outlet systems lack a natural means for water to escape the treatment facility, more vigilance is advised in the case of a power outage. If you have a pumped outlet system and the power is off for a brief while, you shouldn’t worry too much since the system has enough capacity for a few standard toilet flushes. Please be aware that if it fails for an extended length of time, the water levels in the system will ultimately increase, and you may end up with sewage on your lawn.
- Sludge Production: Sludge is the residue generated during physical, chemical and biological treatment. A major environmental challenge for wastewater treatment is the disposal of excess sludge produced during the process. Excessive sludge results in floating sludge which contaminate and affects the entire BOD process.
- Usage of Diesel Generators: As a constant power supply is a need for treatment facilities, diesel generators are required during power outages. Using an excessive number of diesel generators results in excessive carbon emissions, further degrading the environment as the daily cost of fuel rises.
- Excessive Amount of Chemicals: Insufficient amounts of necessary chemicals, such as phosphorus, nitrogen, ammonia, etc., may render the sewage treatment facility inoperable. There are numerous ways to reduce COD (Chemical Oxygen Demand), including the removal of nitrogen through the denitrification process.
So, What is The Solution?
With the development of technology, human society is moving more and more toward renewable energy. Solar energy must be used to meet the sector’s future energy demands since natural resources like coal and natural gas are finite and will ultimately run out. Solar power plants are also the most dependable renewable energy source.
With ever-rising population growth, the need for power in the seed processing industry is higher than ever.
SunShell Power provides rooftop solar solutions for all seed processing plants. Solar modules have a 25- year life expectancy and need no maintenance, making the plant a stable power source.
For water treatment plants, we offer two types of solar solutions:
- Grid-connected Solar Rooftop Plant
- Solar Street Light
Grid-Connected Solar Rooftop Plant (On-Grid):
Grid-connected solar power plant with little maintenance and accessible net-metring capability, as well as a credit system based on power banking. This sort of power plant is excellent for establishments with high demand and infrequent power outages.
Even though in SunShell Power, every solar power plant is important and valuable for us, for the water treatment plant, we would highly suggest the authority install on-grid solar power plants. From our previous experiences, we have pointed out several points from which we have declared the Grid-connected plant to be a clear winner:
- These systems are ideally suited for very high power usage and for lowering energy expenditures,
- On-grid plants can be installed with or without net metering,
- On-grid systems are very cost-effective and easy to install,
- As there is no battery backup in the system, there are fewer chances of battery failure and hence the maintenance is minimal which can be helpful in the busy environment of the processing unit.
- The most dependable renewable energy source is generated by on-grid power plants.
The average payback of a grid-connected solar power plant in a seed processing plant is around 3.5-4.5 years, although it can change based on the electrical load of the plant.
- Solar Street Lights: As a water treatment plant’s complex is large and frequent operations, maintenance, and checkups are a routine occurrence, sufficient lighting is a crucial issue. The majority of seed processing facilities include storage areas where expensive and dangerous chemicals are kept in big quantities. They also have sludge management departments that need daily maintenance and inspection. These are the areas where solar lights may be used as nighttime safety equipment.
- Two in One (Semi-integrated): Used for a variety of purposes, these are easy to install and are low-maintenance.
- Solar Mini Mast: Best for places with unstable power sources, uses green energy and needs almost maintenance.
Waste and sewage water treatment plants require a huge amount of electricity to keep up their operations. Not only producing green energy, but also auditing the energy consumption is also an important aspect.
Energy auditing is an energy assessment. This assessment looks at how energy flows through a structure, process or system in order to minimize energy input while preserving or increasing human comfort, health, and safety. According to the definition of ISO 50002 standard, an energy audit is a systematic analysis of energy use and energy consumption within a defined energy audit scope, in order to identify, quantify and report on the opportunities for improved energy performance.
There are three types of energy audits:
- Walk-Through Audit,
- Energy Diagnosis,
- Investment Grade Audit.
Depending on the purpose and potential savings the type of energy audit is chosen.
If the priority is to identify potential savings and further studies a walk-through audit is recommended whereas if the intention is to invest a large amount of money in energy efficiency measurement an Investment Grade Audit is done.
- Energy Auditing helps reduce costs in the facility,
- It helps reduce environmental damage and pollution,
- If any energy is active then it can be detected.
Become A part of The Green Future:
India has set a goal of having net-zero emissions by the year 2070 while the rest of the world makes plans to become carbon neutral. The government is providing a number of programmes and laws for solar installations; it is our responsibility to do our bit to help this green goal,a success.
In the wastewater treatment industry, solar power plants indeed have a huge potential, as the majority of the waste and water treatment is done during the rush period which is the day-time and the process requires a lot of power and the plant should be powered by green energy.
Water treatment plants around the world are switching to solar by installing solar rooftop plants. In Jordan Valley, the Tal-Al-Mantah wastewater treatment plant has installed a ground-mounted solar power plant which delivers 90% of the treatment plant’s electricity requirements.
The state government of Gujarat has sanctioned solar projects worth Rs. 13.61 crores for water treatment facilities. With this sum of money, up to 15 water treatment and/or sewage treatment facilities for 11 municipal treatment plants might be built.
Given that the state only takes up 6.39% of India’s geographical space and has access to just 2.28% of the nation’s water supplies, it is critical that the water-strapped state consider the possibility of recycling treated wastewater.
Additionally, there are other options available for other regions of the nation where wastewater may be treated utilizing renewable resources.By 2030, the Indian Central Government hopes to have installed 500 GW of renewable energy. Therefore, it is imperative that industry transition to solar power in order to make the earth greener by lowering its carbon impact.