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Whether you run a restaurant, car wash, or an office building, wastewater is an unavoidable part of business operations. But what happens to it after it flows down the drain or is flushed away? The journey of business wastewater – from sinks, toilets, or industrial processes – is an intricate one, involving sophisticated treatment systems designed to make it safe for the environment and ready for reuse.
In this article, we’ll explore the path wastewater takes after it leaves your business, the different types of wastewater produced by various industries, and the crucial role treatment plants play in managing and cleaning this water.
Where does my business wastewater go?
Once wastewater leaves your business, it enters a complex system of underground pipes that make up the sewer network. This network collects wastewater from businesses, homes, and public buildings, and channelling it toward a wastewater treatment plant. Depending on the location and industry, businesses may discharge their wastewater into one of two main types of sewers:
- Foul water sewer: This system carries wastewater from sinks, toilets, and internal drains. It includes sanitary wastewater and process water from industrial businesses.
- Surface water sewer: This system handles rainwater runoff from roofs, parking lots, and other outdoor areas. Surface water often doesn’t need as much treatment, as it contains fewer pollutants, but in some cases, it may carry contaminants that also require processing.
In some cases, large industrial businesses may be required to pretreat their wastewater onsite before discharging it into the public sewer system, especially if their wastewater contains harmful substances.
Types of wastewater produced by different businesses
Not all wastewater is the same. The type of wastewater a business produces depends on its operations, and the treatment it requires can vary greatly. There are four primary categories of business water which are:
1. Sanitary wastewater (domestic wastewater)
Sanitary wastewater includes water from restrooms, kitchens, and employee areas. It’s typically made up of human waste, soap residues, and small amounts of organic matter. Most industries will produce some amount of sanitary wastewater.
- Treatment: This type of wastewater is typically low in harmful pollutants and is treated primarily through biological processes. Treatment plants use microorganisms to break down organic matter before the water is filtered and cleaned.
2. Process wastewater
Process wastewater comes from industrial processes and manufacturing operations. This water often contains a mix of chemicals, heavy metals, oils, and solvents, depending on the type of industry. The industries that tend to produce process wastewater are manufacturing, chemical plants, food and beverage production and pharmaceuticals .
- Treatment: Because this water can contain harmful or hazardous materials, it often requires advanced treatment methods such as chemical neutralisation, sedimentation, and filtration before it can be safely released. Some industries must pretreat their wastewater on-site to reduce its pollutant load before sending it to the main treatment plant.
3. Cooling Water
Some businesses, particularly in manufacturing and power generation, use large amounts of water for cooling equipment or processes. Cooling water may not come into direct contact with raw materials, but it can still become contaminated with chemicals or heat, which affects aquatic environments when discharged.
- Treatment: Cooling water may need temperature regulation and removal of any dissolved chemicals or oils before it is released. Inadequate cooling can lead to thermal pollution, a serious environmental concern.
4. Trade effluent
Trade effluent is wastewater generated by businesses involved in activities like food processing, brewing, or laundries. It may contain organic materials, fats, oils, greases (FOGs), and chemicals.
- Treatment: Trade effluent needs specific treatment based on its content. Some of it is biodegradable, while other components (like FOGs) can cause blockages in sewers. Treatment often involves biological digestion, physical separation, and in some cases, chemical treatment to break down these substances.
The path of business wastewater to treatment plants
No matter what type of business you run, your wastewater will eventually make its way to a wastewater treatment plant. But before it reaches the plant, the water may pass through interceptor tanks or pumping stations designed to help remove large debris and regulate flow, ensuring it moves efficiently through the system.
Once at the treatment plant, business wastewater goes through several steps:
1. Primary treatment
The first step in treatment involves screening and filtering out large solids like rags, plastic, or food waste. In businesses such as food processing or manufacturing, this can be a crucial step for preventing clogs and damage to the system.
Next, the wastewater enters settling tanks, where heavier materials sink to the bottom and form sludge, while oils and fats float to the surface for removal. This sludge is further processed and can be used to generate biogas or as agricultural fertiliser.
2. Secondary treatment
The second stage is biological treatment. Microorganisms are introduced to the wastewater to break down organic pollutants like fats, oils, greases, and biodegradable materials. In industries with high organic loads, like food and beverage production, this step is essential to reduce harmful substances.
3. Tertiary treatment
In cases where high standards of discharge are required, the water undergoes tertiary treatment. This can include processes like chemical disinfection, filtration through activated carbon, or UV treatment to kill pathogens. Some industrial wastewaters may also require the removal of specific chemicals or heavy metals.
After these treatments, the cleaned water is either discharged into natural watercourses (rivers, lakes, or the sea) or reused in industrial processes for non-potable purposes, such as equipment washing or cooling.
The environmental impact of business wastewater
Businesses, especially those in manufacturing and production, have a significant impact on the environment through their wastewater. Discharging untreated or improperly treated water can lead to the contamination of water bodies, harming wildlife and ecosystems. This is why wastewater regulations are strict, with businesses required to monitor and control the quality of their discharge.
Compliance with regulations
In the UK, businesses that produce trade effluent must have a permit from their local water authority. Non-compliance with regulations can result in hefty fines, making it essential for businesses to ensure that their wastewater is properly managed, pre-treated where necessary, and discharged according to local and national standards .
Trade effluent consent is a vital part of wider legislation which protects the environment. It is illegal to discharge trade effluent without consent and doing so carries the risk of prosecution and fines. If your business produces trade effluent, you can apply for consent here.
The role of modern technology in business wastewater management
Technology is playing an increasingly important role in how businesses manage and treat wastewater. With growing pressure to reduce environmental impact and conserve water, many industries are adopting innovative technologies and sustainable practices:
- Smart sensors: These devices monitor wastewater quality in real-time, detecting any contamination or issues early and helping businesses avoid costly fines or system damage.
- On-site treatment systems: More businesses are investing in on-site treatment facilities to handle their wastewater before it enters the public sewer. This not only reduces the environmental load but can also save on disposal costs.
- Water recycling: Many industries are turning to closed-loop systems where water is treated and reused multiple times, reducing overall water consumption and cutting costs.
How businesses can help improve wastewater management
Every business, regardless of size or industry, has a role to play in improving how wastewater is managed. Here are a few steps businesses can take:
- Implement pre-treatment systems: Pre-treating water on-site ensures that pollutants are reduced before discharge, helping to prevent issues in public sewers.
- Reduce water usage: Install water efficient equipment and reuse water wherever possible. Simple practices like using water efficient cleaning systems can make a significant difference.
- Proper disposal of FOG and chemicals: Ensure that FOG and hazardous chemicals are disposed of properly and never enter the drainage system.
