19: Water and wastewater management

Population and economic growth have contributed to exponential rise in demand for water resources. As a result, 36% of the world's population are living in water scarce regions. For the low and middle income nations, urbanization has created various challenges related to water resources including poor water quality, sporadic water supply and inconsistent sanitation infrastructure, for the informal settlements and sub-urban settlements in particular. Various SDG targets for water include improving water quality, streamlining integrated water resource management, and efficient water usage across sectors.

Developing countries require interventions in collection and treatment of industrial wastewater. Industrial wastewater is “the aqueous discard that results from substances having been dissolved or suspended in water, typically during the use of water in an industrial manufacturing process or the cleaning activities that take place along with that process. “ Wastewater can be treated up to different qualities to satisfy demand from different sectors, including industry and agriculture. It can be processed in environment friendly ways and can be further reused.

Waste water treatment generally has various steps designated as primary, secondary or advance treatment ( depending on the degree of purification). Primary treatment plants utilize physical processes such as screening, skimming, and sedimentation to remove pollutants that are settleable, floatable or too large to pass through screening devices.

In secondary treatment physical treatment processes that are part of primary treatment are augmented with biological treatment ( such as microbial oxidation) of waste. The biological treatment mimics nature by using microorganisms to oxidize organic matter. A typical wastewater treatment process consisting of various steps is shown below:

• The inflowing waste water is passed through screening and grit tans which removes large floating objects ( e.g. rags, sticks etc), suspended debris and sand that settles very rapidly which may damage the equipment.
• Sedimentation tanks or primary settling tanks ( here flow’s speed is reduced efficiently to allow most suspended solids to settle out by gravit
• Aeration removes excess and objectionable gasses.
• The sludge that settles is removed for further processing and is transferred to the digester, where they are decomposed by microorganisms. ( Further the treated biosolids are sent to landfills or used as fertilizer post odor control treatment.
• Secondary treatment removes additional suspended solids, beyond what is achievable in simple sedimentation.
• The cleaned water is treated with chlorine or ultraviolet light to kill remaining harmful bacteria
• Cleared water is discharged into water supply sources such as streams and groundwater.

Industries use large amounts of water for heating, cooling, for production of goods, services and this generates a substantial amount of waste water. One of the industry examples is mining, which is traditionally associated with unregulated waste water discharge, especially in the developing world where such discharges pollute the usable water supply, also seeping into the ground and contaminating aquifers and wells. Another such example is coolants and cooling water used in industrial processes, for instance in steel manufacture and coke production. The discharge usually has higher than normal temperatures adversely affecting marine life.

Another major waste generator is food and agriculture, which mainly produces organic waste water with high biochemical oxygen demand resulting in low oxygen levels and anaerobic conditions.

Industry Best Practices

Wastewater treatment is an important step in ensuring that our local ecosystem is safe and well-protected. It is also a significant obligation for any industrial operation that generates wastewater. Therefore, adequate waste water treatment measures become even more important, some the important practices are listed below:

Create a robust monitoring plan

Industrial wastewater treatment plants are large and complicated, with several processes, pieces of equipment, and staff all working together to accomplish the desired outcome. With so many moving parts, it's simple to understand why competent management is so important.This is why a robust framework with all the different elements is of prime importance.
A general framework should include:

• List of different treatment requirements according to the waste composition.
• List all practices that need to be controlled such as:
  a.Plant site runoff
  b.Spillages and leaks
  c.The disposal of sludge and waste
  d.Any drainage from storage of raw materials
  e.Any other potential hazards

And other requirements according to the government regulations such as Hazardous Waste ( Management and Handling) Rules, 2016 in India.

Accurate output monitoring system

Keeping an eye on the water flowing out of the plant to see if there are any issues that need to be addressed in the processes is of prime importance.
Oil and grease should be chemically broken down throughout the water treatment process, and there should be no lingering odour in the effluent.
Creating a systematic procedure for monitoring and measuring the quality of the output, as well as ensuring that the water treatment facility is producing the desired outcomes. This is critical because a malfunctioning plant can have major consequences for the local ecosystem.

Creating an internal and external contact chain

In most cases, local governments impose their own criteria and regulations on wastewater treatment plants. While the individual departments oversee industrial wastewater producers in line with national and state law, international restrictions also come into play.
With this in mind, having a direct channel to local government and establishing a positive relationship with field regulators becomes even more crucial.
An internal chain of communication is also essential in this case.
The teams must understand who they report to inside the organisation and who they must call in an emergency.

Cycle through primary and secondary treatment processes

Integrating primary and secondary treatments is an excellent technique to increase the efficiency of treatment plants. Primary treatments remove pollutants from wastewater using physical methods such as gravity separation. This should be followed by a secondary treatment phase that leverages biological mechanisms to complete the treatment.
Develop a system in which any contaminated water is cycled back through these primary and secondary stages. Test and monitor all water output to ensure that the treatment steps are producing the desired outcomes.
Note that rules and regulations are subject to change, so remain up to date on these changes to ensure your facility is working properly.

Promotion of waste resource recovery facility

Historically, waste treatment concentrated on eliminating impurities and pathogens from water in order to recover it and safely discharge it into the environment. To promote sustainability, treatment plants should be considered as water resource recovery facilities that collect and reuse elements of wastewater. This process begins with water (which may be utilised for agriculture, industry, and even human consumption), then proceeds through nutrients (nitrogen and phosphorus), and finally to energy generation. These resources can produce income streams for the utility, possibly transforming the wastewater process from severely subsidised to revenue-generating and self-sustaining.

Case study

Wastewater Management Strategy by The Coca Cola Company

The Coca-Cola Company is a global corporation that manufactures a wide range of non-alcoholic beverages. Coca-Cola acknowledges the necessity of responsible water stewardship and has adopted different wastewater management methods throughout its 700 sites in over 200 countries.Water is a key resource for the company's operations, thus it has built a thorough water stewardship policy.

The company’s wastewater management plan is part of the company's larger sustainability framework, which includes pledges to minimise its environmental footprint, increase its social effect, and strengthen governance.

The company's waste water management strategies include:

Wastewater Reduction

Company has taken a number of steps to reduce its water use and the volume of wastewater produced.
For example, the company has invested in water-saving technology like waterless bottling and has refined its manufacturing processes to reuse wastewater.

Wastewater Treatment

The plants are designed to treat wastewater to meet local regulatory standards so that it can be reused or released into the environment. To enhance the quality of its effluent, the company has invested in modern wastewater treatment technology such as biological treatment and membrane filtering.

Collaboration

Further, the brand works with a variety of stakeholders, including local communities, governments, and non-governmental organisations, to promote sustainable water management practices. To detect and manage water-related hazards, the firm participates in collaborations and projects such as the World Wildlife Fund's Water Risk Filter.

As per the company’s report, they have reduced their water usage by over 30% since 2004. The company has also replenished over 150 billion liters of water back to communities and nature through various projects. The company states that they have implemented projects to restore wetlands, protect watersheds, and promote sustainable agriculture. The company has provided access to safe drinking water and sanitation facilities in over 100 countries.

The wastewater management strategy aims to protect local ecosystems and reduce the risk of water pollution. It is an integral part of its broader sustainability framework where the company commits to responsible water stewardship for benefits for the environment, local communities, and its operations.