SUSTAINABLE WASTEWATER TREATMENT

WASTE WATER• Wastewater is any water that has been affected in quality. It can be

described as contaminated water or “sick Water”.

• Wastewater can originate from homes, industrial and factory waste, commercial or farming activities, surface runoff or storm water.

• Surface run off can include anything from harmful substances that wash off from roads, parking lots or rooftops.

• Wastewater is harmful to human health if not treated properly after being disposed into the environment.

WASTE WATER• Sewage is usually treated at a wastewater treatment plant.

• Wastewater begins from toilets, shower room, laundry room and kitchen sinks.

• Also, water used for washing and cleaning purposes such as for gardens, swimming pools, washing machine and storm water is included in wastewater but not specifically sewage water.

Wastewaters can be categorised as

• DOMESTIC WASTEWATER :Used water discharged from the residential, commercial and industrial area of a city and collected though the sewage system.

• INDUSTRIAL WASTEWATER:Generated from medium to large scale industriesManufacturing industries produce a large volume of wastewaters

WASTEWATER MANAGEMENT

• Water is one of the most important natural resources that we have on Earth. Water is used for not only homes, but also for businesses, institutions and industries and many more.

• The increase in human population and boom in industry all over the world means the discharge of wastewater is also increasing at a rapid level

• Therefore the management of wastewater should be more sustainable and efficient.

WASTEWATER MANAGEMENT• Effective wastewater management means to reduce the level of

pollutants in wastewater before it is being discharged into the environment without harming human health or to the natural environment

• In rural settings, water is discharged naturally by the sun, vegetation and soils

• In urban settings water needs to be discharged by appropriate technology because of natures inability to handle large volumes of wastewater

Types of Wastewater collection

There are two types:• Centralised System:Centralised system is a large scale water collection system that collects water from many types of users for treatment at one or multiple sites.

• Decentralised System:Decentralised system is an on-site system which collects wastewater from individual users or small groups of users from neighbourhoods or residential areas.

SUSTAINABILITY

• A sustainable approach gives many benefits to not only the environment but also improve food security, health and a country’s economy as a whole

• A sustainable way to manage wastewater is to recycle and re-use water.

• For eg: waste water can be used over and over again for a cooling plant, also recycled wastewater can be used for construction and concrete mixing.

AWARENESS & PREVENTION• Big companies & stakeholders should take initiative to raise awareness

for wastewater management.

• Water is a scarce resource and therefore needs to be used with care, strict rules and regulations need to be put in place by authorities in order for there to be no waste.

• It is also important to assess, monitor and manage for reuse in order to avoid negative impacts on human health.

PROCESS OF SUSTAINABLE WASTEWATER TREATMENT

Flow diagram of a typical treatment plant

Treatment system

Normally, a wastewater treatment plant is designed for either, • Preliminary Treatment System• Primary Treatment System • Secondary Treatment System • Tertiary Treatment system.

Preliminary Treatment System

• To remove any floating materials and large inorganic particulate matters

• This treatment is also known as Pretreatment in common treatment system.

• Approach channel : Convey and dampen the flow of wastewater pumped to the treatment plant

Screen chamber : Removes large size of floating materials Grit chamber : To remove suspended settle able solid Skimming tank : Remove excessive oil and grease Sump and pump unit : Waste water is collected in a sump and pumped into higher level of treatment

Flow diagram of a preliminary treatment system

Primary Treatment System

• Removes solid and organic material• Screen chamber : Removes most of large floating material Grit chamber : Separate most of heavy suspended solids Primary sedimentation : Reduce 60%-70% of fine settle able suspended solids

Flow diagram of a primary treatment system

Secondary treatment system

• Secondary treatment is also known as a biological treatment because biological process take place in this treatment

• By the use of microorganism, primary bacteria to covert biodegradable organic matter contained in wastewater

• The oxygen level in the wastewater will be changed in order to produce aerobic and anaerobic environment

• The common type used in our country is oxidation pond.

OXIDATION POND

Oxidation pond

• Oxidation pond also known as lagoon• Large and shallow ponds designed to treat wastewater through the

interaction of sunlight, bacteria and algae• Temperature in our country is suitable for aerobic bacteria as bacteria

which can only survive in warm temperature

Tertiary treatment system

• Tertiary treatment is also known as an advance treatment system • The main purpose in this treatment is to reduce nitrogen and

phosphates which can cause problems when they get into water body by enhancing the growth of algae blooms

This treatment is provided when :1. Quality of standard treated waste water (secondary) is inappropriate for

final disposal requirement2. The concentration of leftover organic material or suspended solids require

further removal of specific reuse of wastewater3. Concentration of nutrient is high for final disposal

Case Study: Rio de Janeiro’s Wastewater treatment plant

Rio De Jeneiro

• Is the 2nd most populated area in Brazil

• Is the 3rd biggest metropolis in South America

• Rio hosted 2 mega events over the past couple years which are the FIFA World Cup and the Olympics in 2014 and 2016 respectively.

• Due to the events, they have upgraded their wastewater treatment plant which is more sustainable than the previous one.

Problems faced in Rio

• The level of water cleanliness is at a critical point.• The wastewater from homes and commercial buildings are left untreated

and they bypass into the sea.• It is said the beaches in Rio contain virus 1.7 million times more than in the

Californian beaches which are considered to be hazardous.• Raw sewage and garbage can be seen floating in the water.• The growth of super bacteria has increased.

Solution to the problem

• Rio has decided to upgrade their infrastructure by building a new water waste treatment plant based on a Dutch technology known as the Nereda technology.

• Its main priority was to cater the visitors during the Olympics in 2016.

Nereda waste water treatment plant

• It was built to cater up to 480,000 people.• It costed 164 million Euros to build.• The project began in 2012 in preparation of the Olympics.• It is located in a place called Deodoro where the Olympics sport complexes

are located.• The capacity of this plant is 10 times bigger than the original one.

Treatment process

• There are 3 steps in this process.

• First phase – Simultaneous fill and draw will be carried out.• Second phase – Aeration• Third phase – Sedimentation

Benefits of having Nereda waste water treatment plant

• Cost effective• Uses less equipments• Low maintenance cost• A sustainable way to treat water• It is a chemical-free process• Highly energy efficient• Productive• Allows the citizen to live in a more sustainable

condition

SUSTAINABLE WASTE WATER TREATMENT

ADVANTAGES DISADVANTAGESImproving the quality of life High capital and operating cost

Preserves environment. People repelled by ‘purified sewage’ water.

Waste minimization High energy consumption

Recovers energyConserves nutrients and reduce the need for artificial fertilizer

POSSIBLE PROBLEMS WITH THE WASTEWATER TREATMENT.

Nuisance from odor.

• Induce public interference• All treatment system emits odorous emission.

Aging infrastructure and workforce.

• Aging of the system’s infrastructure would cause many problems and failures to the system:

Cracking Collapsing Clogging• Lack of professional workers and experience would affect management

system.

Funding concern.

• Important factor to run, maintaining and improvise the system.

• A huge capital is needed for the sector of sustainable wastewater treatment system.

Building Cost Operational and Maintenance Cost Workforce Research & Development• Government intervention is required.

STRATEGIC PLANNING FOR FUTURE DEVELOPMENT.

Create awareness amongst society.

• Make more public campaign and talk.• Social media advertisement

Learn from other countries the management system of wastewater treatment.

• Follow the standard from other countries that had successfully used the system.

• Improve control strategies in terms of the process and effectiveness of system that have been implemented.

Create water quality standard.

• Set a target to achieve In a period of time.• Use more biodegrable chemical

Hire professional workers to operate the system.

• Transfer high quality scientist to train domestic workers.

• Hiring more experienced workers in operating the system.

Develop a new technology

• New high technology and asset• Benefit to country in a long run

Conclusion