What Is the Lifecycle of Wastewater?
Wastewater management plays a fundamental role in safeguarding public health and the environment. Whether wastewater comes from households, industrial activities, or commercial operations, it goes through multiple stages of treatment before it is discharged or reused. The standards for the quality of this water are set by UK regulations, meaning that, in many cases, these treatment processes are a legal requirement.
At the same time, each sector produces wastewater with unique combinations of contaminants, and this requires tailored treatment approaches to meet the required legal standards. In this post, the wastewater disposal experts at Universal Tankers outline the lifecycle of wastewater, from use to treatment, disposal and reuse, with a focus on sector-specific needs and the technologies used in treatment.
Treatment technologies: primary, secondary, and tertiary treatment
Wastewater treatment consists of several stages designed to remove pollutants and prepare water for safe discharge or reuse. The wastewater treatment technologies applied at each stage vary based on the wastewater source and the required treatment level but, in general, a three-stage treatment process is the most effective for all types of commercial wastewater.
Primary Treatment
Primary treatment focuses on removing large solids and debris using screening and sedimentation. This step prevents blockages and enables smoother downstream processing by preparing wastewater for further biological or chemical treatments. In some cases, chemicals are added to improve the efficiency with which solids settle and are removed.
Secondary Treatment
Secondary treatment relies on biological processes to break down organic matter. Microorganisms are introduced to reduce biochemical oxygen demand and chemical oxygen demand, both of which are key metrics by which water quality is judged. They track how much oxygen is consumed as organic materials break down.
Technologies commonly used in secondary treatment include activated sludge, trickling filters, and anaerobic digestion. These processes prepare wastewater for safe discharge, although in some cases, a third stage of treatment will be necessary to further refine the water before it is discharged.
Tertiary Treatment
Tertiary treatment uses advanced processes to remove remaining contaminants.This stage may include nutrient removal, disinfection, or filtration. Technologies such as reverse osmosis, membrane bioreactors, and UV disinfection are often applied here. Tertiary treatment is critical when treated water is intended for reuse in industrial processes, irrigation, or cooling systems.
The lifecycle of wastewater in key industries
Many UK industries generate wastewater, but some do so in much higher volumes than others. Some industries also face stricter standards and other specific regulations, often because they generate wastewater with unique characteristics that requires specialised treatment approaches.
Effective water management plays a crucial role in understanding and minimising the environmental impacts of these processes across different industries, and environmental regulations are another factor that can affect wastewater treatment processes. Below is a detailed look at how wastewater is treated across some of the sectors that generate the highest volumes.
Brewery and distillery wastewater
The brewery and distillery sector generates high volumes of wastewater during brewing and fermentation that are rich in sugars, ethanol, yeast, and cleaning chemicals. Primary treatment starts by removing solids like grain particles and hop residue through screening and sedimentation.
Due to the high organic load, anaerobic digestion is commonly used in secondary treatment to break down matter and produce biogas. In some cases, this biogas can then be used as a renewable energy source to power further brewing operations. Advanced tertiary treatment, such as membrane filtration, is often applied to further refine the effluent, especially in cases where a business wishes to reuse water for cleaning, cooling, or non-potable applications. This may also be required if water is to be released back into the environment.
Domestic waste
Domestic wastewater includes greywater from sinks and showers, and blackwater from toilets. It is collected through municipal sewer systems and sent to domestic wastewater treatment plants for processing.
Primary treatment removes solids and debris using screening, then secondary treatment typically relies on activated sludge to break down organic pollutants. Treated water is either discharged into rivers or reused for non-potable applications, such as irrigation. Tertiary treatment, such as UV disinfection or chemical processes, may also be applied when water is intended for reuse.
Food and beverage
Liquid food waste, such as that from food processing plants, contains high levels of fats, oils, grease (FOG), and organic matter. Dissolved air flotation is frequently used during primary treatment to remove FOG and suspended solids. Secondary treatment often involves anaerobic digestion or activated sludge, which breaks down organic material. Biogas generated during anaerobic digestion can be captured and used as a renewable energy source. Tertiary treatment systems, such as membrane bioreactors, help to bring the treated water to the required standards for reuse in irrigation or cooling systems.
Hospitality
Commercial wastewater, including that from restaurants and hotels, is similar to domestic wastewater but may contain higher levels of cleaning chemicals and organic matter. Primary treatment removes larger particles, and secondary treatment uses biological processes to degrade organic content. Tertiary treatment methods, including UV disinfection or chemical treatment, may be added to confirm that wastewater meets discharge regulations or is safe for reuse.
Industrial
Industrial wastewater poses unique challenges due to its varied contaminants, including heavy metals, solvents, and toxic chemicals. Pre-treatment neutralises harmful substances before secondary or tertiary treatment. Technologies such as reverse osmosis, nanofiltration, and membrane bioreactors help to treat industrial wastewater in line with UK discharge regulations. Industrial sludge, the by-product of wastewater treatment, is treated separately through sludge digestion or other methods, depending on the contaminants present.
Maritime
Maritime wastewater includes greywater from sinks and showers, blackwater from toilets, and bilge water, which collects oil and other contaminants. Onboard systems typically use oil-water separators to treat bilge water before it is discharged. Sewage treatment systems onboard ships mirror land-based systems for treating blackwater.
In compliance with MARPOL regulations, treated water is either discharged at sea or transported to port facilities for further treatment.
Wastewater reuse and the circular economy
Wastewater reuse is increasingly important, particularly in sectors facing water scarcity or high water demand, such as food processing and industrial manufacturing. These industries may have binding regulatory targets to reduce water consumption, and reusing water is the most effective way to achieve these. Treated water can be reused for many non-potable purposes, including irrigation, cooling, and cleaning, and is a better alternative to fresh water for this purpose. This approach aligns with circular economy principles by promoting resource reuse and reducing waste.
The wider environmental aspects must also be taken into account. For example, wastewater treatment generates sludge, which contains concentrated pollutants and must be dealt with accordingly. In some cases, treated sludge can be converted into biosolids for agricultural use, and some sludge treatment methods, such as anaerobic digestion, produce biogas, a renewable energy source. This means that choosing the right treatment method for wastewater can further contribute to circular economy ambitions.
This is important because it is not only the health of the environment that is at stake when it comes to pollution. Effective wastewater treatment helps protect public health as well as ecosystems - contaminated wastewater poses health risks, as it may contain pathogens and toxic chemicals that can infiltrate drinking water supplies. Untreated wastewater can lead to eutrophication, where excess nutrients cause algae blooms that deplete oxygen in water bodies. This harms aquatic life and can have negative side-effects for human health.
The future of wastewater treatment and reuse
As industries adopt more sustainable practices, wastewater treatment will evolve with advanced technologies and increased water reuse. Already, cutting edge technologies are changing the efficiency of treatment processes and recovering more water and energy that can be reused. Businesses investing in these solutions will not only be ready to comply with changes to UK regulations but can also contribute to a more sustainable future and enjoy a better reputation among consumers as a result.
Partnering with experts like Universal Tankers helps companies manage their wastewater lifecycle efficiently, improving environmental outcomes and operational performance. By embracing advanced treatment methods, businesses can play a pivotal role in protecting the UK’s water resources and advancing sustainability initiatives. To learn more about the wastewater collection and treatment services offered by Universal Tankers
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