Flow and Load Surveys

Aqua Enviro are specialists in all types of flow and load surveys, including the installation of flowmeters, level sensors, analytical probes and automatic sampling devices.

Wastewater parameters that can be monitored or measured  include Biochemical Oxygen Demand (BOD), Total Suspended Solids (TSS), Total Dissolved solids (TDS), Chemical Oxygen Demand (COD), Ammonia, Phosphorous, Nitrogen (TN & TKN) or metal salts. Aqua Enviro have an in-house laboratory where many of these parameters can be measured and have links with specialist subcontract laboratories for detailed, specific analyses.

A flow and load survey can identify issues with facilities’ effluent treatment processes as well as levels of new and emerging micro-pollutants or harmful recalcitrant compounds like VOCs, BTEX and phenols that may require specialist downstream treatments.

Aqua Enviro have developed specialist sampling techniques and methods to evaluate new and emerging materials and compounds and are able to evaluate wastewater treatment sample points, ensuring that samples taken are representative of each stream.

It’s possible to save costs and reduce discharge permit risks by commissioning a flow and load survey for many industrial processes, wastewater and sewage plants – and even marine installations.


What is a flow and load survey?

A flow and load study is a combination of flow monitoring with the relative chemical composition data collected at the same time; combining the two pieces of information allows the effective chemical load to the site to be identified.

Flow and load surveys will assist in the ongoing operation of many wastewater treatment plants and can also act as a useful signpost when designing modifications or replacements to facilities.

Many companies are concerned about the obligations in their consent to discharge; commissioning a survey of this nature will often identify any potential issues with onsite wastewater treatment effectiveness.

Utilising a combination of automatic sampling equipment and flow meters, data and samples are collected and analysed in conjunction with existing site parameters. This presents an accurate snapshot of how efficiently the plant is operating, especially in relation to contaminants in the water.

Flow and load surveys are used for evaluating works performance, identifying and confirming process performance, generating design data prior to upgrade and confirming compliance with discharge consent parameters.

Composition survey

Wastewater is a cocktail of chemical compounds and solid materials, organic and inorganic.  A composition study removes the use of flow metering (used to evaluate load) and focuses directly upon chemical contaminants of interest being applied to the wastewater treatment works.

Typically these components are COD, BOD, TSS, Ammonia and Phosphorus, but with new and emerging compounds including microplastics and micropollutants, the list is extensive.  A composition survey can be undertaken as part of demonstrating effluent compliance with discharge to consent, evaluating process performance, generating site data or undertaking ‘proof of performance’ as part of takeover tests for new assets.

Who needs a flow and load survey?

Flow and load surveys are vital to any industry that has water treatment processes and discharge industrial effluents; having an up-to date survey carried out by a highly experienced company like Aqua Enviro ensures the methodology will be consistent with the parameters set out in an Environment Agency Consent to Discharge.

Manufacturing companies discharging industrial effluent, municipalities and water companies with CSOs or large sewer networks, river catchments and many marine facilities all will have a need for different types of flow and load surveys. Each industry and application has different demands and requirements; trust Aqua Enviro’s vast experience to deliver a cost-effective solution for any of them.

Industrial Manufacturers

Many manufacturers of products that use large amounts of water (for instance pharmaceuticals or semiconductors) will already have wastewater treatment on site but will also be regulated by the Environment Agency and therefore, to avoid fines need to be very careful that their outflows are within consented limits.

Wastewater networks

Water companies and municipalities with extensive wastewater networks will need flow and load surveys in a variety of situations. Aqua Enviro can arrange a customised programme of surveys to suit all sizes of operation.

Marine sampling

Effluents discharged through sea outfalls can affect water and beach quality. Aqua Enviro has worked with marine discharges to help evaluate the impact upon bathing water quality.

Sewage works

Aqua Enviro are experts in working at sewage treatment works and are able to provide, detailed, bespoke solutions to flow monitoring or wastewater composition monitoring challenges.

Aqua Enviro provides these services throughout the wastewater process.  We are adept at working on any installation within a wastewater treatment works, whether Activated Sludge plant (ASP), Trickling Filter, Anaerobic Digester (AD) or sludge handling through thickening or dewatering.

The importance of flow and load surveys

In whatever situation wastewater treatment is being carried out – and a few examples are shown above – flow and load surveys are often vital to ensure the efficient running of plant and that your discharge consent commitments are being met.

Regular flow and load surveys will also indicate when facilities start to need more physical maintenance or have reached end of life.

Identifying weaknesses in treatment processes

In some cases, especially in manufacturing, some (mainly organic) compounds may not be fully treated by companies’ existing wastewater treatment. If there’s any doubt about the effectiveness of these water treatment processes, a flow and load survey will answer those questions.

Meeting your discharge consent

Prosecutions and fines can result in not following the Environment Agency Consent to Discharge limits set for a particular plant or facility. All Aqua Enviro’s surveys and reports are in a form that is acceptable to the Agency so regular flow and load surveys are the best way to ensure discharge consent compliance.

Ensure a new treatment process is working correctly

Flow and load surveys can also be deployed during the build and commissioning of new water treatment processes or refurbishment of existing ones and can validate projected results or point to issues at an early stage.

Optimise water treatment processes

With the cost and availability of fresh water rising fast, many manufacturing companies are attempting to minimise discharges by investing in further water treatment optimisation with the intention of reusing water. A load and flow survey will assist in planning for this, indicating what a water treatment system for the future could look like.

What to expect from a flow and load survey

With Aqua Enviro, the process starts with a site visit/risk assessment and then a plan is generated. Our field staff have great experience of working in all types of situations and are fully trained for the work they will undertake.

The survey could be just a few days or could be considerably longer depending on locations and complexity.

Results are then presented and (if required or requested) interpreted and analysed by our highly qualified staff.

What type of flow and load survey do you need?

A flow and load survey from Aqua Enviro can be customised to suit your organisation’s precise requirements. From a simple survey for a manufacturer to validate discharge consent compliance to a major infrastructure project, we have the resources and knowledge to handle it all.

Having an in-house lab at our West Yorkshire base allows us to offer rapid sample analysis and our highly qualified senior staff can deliver world-class interpretation and analysis of survey results.

Auto samplers

We use two types of auto-sampler. A diurnal sampler will measure variations throughout the day and normally sample hourly whilst a composite sampler will take a daily average. Samples are picked up and transferred to our lab for analysis.

Samples are normally gathered over a period of days or weeks for the most accurate results.

Temporary flow monitors

Temporary flow monitors can be fitted to most pipes and flumes and measure the hydraulic water flow. Again, these are often left for some weeks to ensure accurate results are obtained.

Design, commissioning and compliance.

A flow and load survey is useful for a number of reasons through many parts of industry that utilise effluent treatment. First as a design aid when specifying and designing plants; second as a check whilst commissioning plants to validate the design, and third as the best tool for ensuring plant compliance – which normally involves regular sampling.

For all types of flow and load tests, Aqua Enviro are the people with the knowledge and the experience. To talk to an engineer who’ll understand the science of your organisation’s unique issues, call or email us today.

Read our Case Study: Flow and load survey at Thames Water’s Mogden Sewage Treatment Works (STW)

Previous clients include:

Severn Trent Water    Anglian Water    Thames Water     Scottish Water    Stantec   Mott MacDonald

"Efficient, Effective, Professional, Flexible, Value for Money!"
Senior Engineer, Process
"We employed Aqua Enviro to undertake flow and load surveys at three of our wastewater sites. They provided a professional service, I would have no hesitation in recommending Aqua Enviro for other such surveys at our sites."
Project Manager, Scottish Water
“I’ve been incredibly impressed with the team, in so far as their ability to quickly gain a reasonably good understanding of a complex works, their rapid response to minor operational changes on site and willingness to adjust the sampling plan to ensure the best outcome. Rowland and his team have fully embraced Thames Water’s safety culture and completed the site work with Zero incidents, Zero harm and Zero compromise. I look forward to receiving the results and final report.”
Senior Engineer at Thames Water

For more information about how Aqua Enviro
can help you, contact us...

Paul Pickard

Technical Sales Manager


01924 242255

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