F.A.Q

Here are some of our frequently asked questions

Why is there a visible plume from the stack?

The Rivenhall plume abatement system uses Best Available Techniques to prevent a visible plume. Like any complex piece of it equipment it requires testing and commissioning to ensure it can be effective in all climatic conditions. The information previously approved under condition 17 of the planning permission for the Rivenhall IWMF, prior to Indaver taking control of the site, did not contain any information regarding the commissioning or calibrating of the plume abatement equipment before it was brought into use. Working alongside Essex County Council, Indaver have sought to rectify this omission by submitting a non-material amendment. The non material amendment allows the submission of  management plan which explains likely visible plumes over the testing period. In order to test in all climatic conditions the management plan covers a testing period up to December 2026. 

Why can I see steam from other parts of the plant?

The Rivenhall EFW  facility has a vacuum unit which moves clean steam through the process from boiler to turbine and back again. There are two parts of the system. A start up ejector which vents steam to atmosphere and a holding ejector which does not.  During commissioning the start up ejector is used heavily until all parts of the plant are running efficiently. After all elements are commissioned the start up ejector should only be used at plant start up which routinely occurs once a year. During normal operation the holding ejector is in use and no steam is vented to atmosphere from this system. In addition to this steam may be visible on occasion from roof vents during start up. The plant is due to finish commissioning in Feb 2026. 

Why are Indaver applying to remove the visible plume condition?

The plume abatement system consumes 4 megawatts of electricity—enough to power approximately 12,000* UK households for an entire year. This energy is used solely to eliminate a plume that appears intermittently on cold days and provides no environmental benefit.

(*Based on an annual average household consumption of 2,700kWh Source: Ofgem)

The planning application to remove the plume abatement condition has been submitted and comments can be made by the public to the Waste Planning Authority either via View and comment on planning applications | Essex County Council using the reference ESS/23/25/BTE or by email to mineralsandwastedm@essex.gov.uk quoting the reference.

Are there negative environmental effects if I can see a plume?

No. The plume abatement system and the flue gas cleaning system are separate systems.  The flue gas cleaning system is designed to remove pollutants prior to leaving the stack. This is always in operation and the plant will never run without it.  The plume abatement system is purely a cosmetic system to reduce the visual impact of condensing water vapour.   Whether the plume is visible or not is not an indicator of the environmental performance of the plant.

Does Indaver have a valid permit to start operating?

Yes, the current Environment Agency (EA) permit allows us to start operating the plant, and all pre-commencement conditions have been fulfilled and agreed with the EA. Additionally, the EA have confirmed that it is not necessary to build all parts of the IWMF in order to be compliant.

Are Indaver building an Anaerobic Digestion Facility?

Anaerobic Digestion (AD) is a natural process where microorganisms break down organic matter in the absence of oxygen, producing biogas and a nutrient-rich digestate. An anaerobic digestion plant is usually used to process organic matter, predominately food waste.

In Essex, food waste collected from households is recycled via anaerobic digestion. Since a change of contracts ECC, WDA food waste is now taken to a facility in Dagenham. There is also an operational plant in Halstead, although this is not currently being used by ECC.

Indaver has planning permission to build an AD facility and monitors the market closely to look for opportunities as the need arises.

Will Indaver build a Materials Recycling Facility?

Indaver is an organisation that values sustainability. We have planning permission to build a recycling facility at Rivenhall, but this must be based on need and it would be irresponsible to build a facility that was not required. Our current planning application seeks to amend the use of the permitted MRF to also accept bulky household waste, a facility which is needed in Essex.

The recycled plastics market is facing a recession across Europe. Our competitors are closing plastic recycling plants because of reduced demand, with a Kent recycling facility closing in August 2025, a Sunderland facility earlier in the summer, and a Bristol facility in 2024.

When might i most likely see a plume?

You are most likely to see a plume during colder, damp days in Autumn and Winter and overnight when the air is colder as the water vapor from the stack   condenses into a visible plume as it mixes with the colder outside air. 

I am concerned about the pollution produced by the plant. Can we expect a dramatic increase of emissions in the local area?

In issuing the EfW plant’s Environmental Permit, the Environment Agency presented its decision summary relating to the potential impacts of the plant on human health and local air quality, which states:

 

Our conclusion is that we consider the proposed facility is unlikely to contribute to any breach of the relevant air quality standards for human health and the environment…

For the proposed design and operation of the incinerator plant, we believe that emissions of particulate matter (PM10 and PM2.5) have been demonstrated to be insignificant…

We are confident that the stringent controls imposed by UK and European legislation coupled with effective day to day regulation will safeguard human health in the locality of the facility. 

Is there a need for this plant?

Yes. In 2024, around 500,000 tonnes of waste from Essex was landfilled or exported outside of the county and even abroad to energy-from-waste facilities on the continent.

Will there be an increase in trucks driving through the surrounding villages?

No. All trucks entering the EfW plant will use the access road via the A120. Although the site road crosses 2 local roads, the bollards in place make it impossible for a truck to turn onto the site road at those points. HGVs are not permitted to use the Woodhouse Lane entrance. All trucks must be weighed on arrival on the weighbridges at the main site entrance.

If the A120 was to be closed for any reason, then the waste trucks cannot enter the site via any other route. We have a contingency plan in place to contact all of our customers and cancel further deliveries if this were to happen. The maximum number of 202 trucks per day amounts to only 2% of the traffic currently using the A120. All of the waste coming to the IWMF is already using the road network to travel to other facilities, so Indaver are not adding any extra vehicles or their emissions to the roads.

Will there be an increase in pollution from all of the waste being trucked to the Rivenhall EfW plant?

No. All of that waste currently goes elsewhere – some of it over to the continent for disposal. Some waste will now undoubtedly have a shorter journey.

What happens to the ash left after burning?

Around 20% of the volume of the waste will remain as non-hazardous ash. This will be processed to remove metals for recycling and the remainder will be processed into secondary aggregate for the construction industry.

Will the EfW plant discourage recycling?

No. The EfW plant will incinerate residual waste left over after recycling.

When disposing of household waste, if cardboard or plastics are wet or soiled in any way, they cannot be recycled as they are considered contaminated. This waste still needs to be disposed of safely and as efficiently as possible.

Investment in new or expanded EfW plant’s only take place in well justified cases, in full respect of the waste hierarchy. EfW’s are sized appropriately to cope with demand and are not a replacement for recycling, the plants simply compliments these efforts by reliably treating waste that cannot be recycled.

Does the facility produce renewable energy?

Yes, approximately half the energy produced is renewable energy. The EfW plant will generate up to 65MW of electricity, some of which will be used to power the facility. The rest will be exported to the electricity grid and used to power homes in Essex. It’s classified as ‘renewable’ energy if it’s derived from an organic renewable source. On average, approximately 50% of “black bin” waste is categorised organic/biogenic which means your bins could be lighting your home.

Why do the plans for the site keep changing?

It becomes necessary to alter plans to suit changing industry needs. The waste industry is continually progressing as technologies change, markets evolve and legislation is amended, which the site plans need to follow.

The current applications are ESS/23/25/BTE (variations to the existing permission), ESS/24/25/BTE (Outline permission for a Carbon Capture Plant), ESS/39/23/BTE/NMA13 (Non-Material Amendment to the description of development). Comments can be made by the public to the Waste Planning Authority either via View and comment on planning applications | Essex County Council  or by email to mineralsandwastedm@essex.gov.uk quoting the references above.

Will the plant harm wildlife?

No. The grounds of the EfW plant have been planted with a variety of vegetation, including around 30,000 trees and shrubs. The medieval moat is home to a small colony of great crested newts that has tripled in size over the past two years. The grounds are home to rabbits, hares, several species of bat, newts, grass snakes, three species of deer, stoats and a wide variety of birds, wildflowers and insects. Our ecologists have developed a Habitat Management Plan to protect and preserve both the wildlife and their habitats.

How much CO2 does the plant produce?

The EfW plant will produce around 500,000 tonnes of CO2 per year. The alternative is to send the waste to landfill where it degrades and produces methane, a much more potent greenhouse gas. Landfill produces an additional 200kg CO2 equivalent per tonne of waste compared to incineration. This means that treating the waste in the Rivenhall  EfW plant actually saves the equivalent of 120,000 tonnes of CO2 emissions each year.

When is construction due to start on site and how long will this take?

Construction started in 2021. Commissioning of the EfW plant will commence in June 2025, and the plant is due to be fully operational in March 2026. Other parts of the IWMF will follow on.

Will there be job opportunities for locals (either in construction or operation)?

Recruitment is now almost complete, but you can see ongoing vacancies here: https://indaver.com/careers/our-vacancies/vacancies-uk

How does the EfW facility contribute to the circular economy?

The circular economy encourages the elimination of waste and the continual use of resources. Unfortunately, as a nation, we still produce a lot of waste (much of it non-recyclable) that needs to be treated.

 

Nonrecyclable waste needs secure and reliable treatment to avoid further pollution. Energy from Waste facilities create energy from these contaminated materials and black bin waste that would otherwise be sent to landfill. Plants like the Rivenhall EfW also offer the highest possible recycling rate of the metals that occur in the residue, contributing to a more resource-efficient economy where as many valuable materials are kept in use for as long as possible.

What are the plans for the historical/listed buildings on the site?

Indaver will be preserving the history of the site by restoring and refurbishing the grade II listed Woodhouse Farm and Brewhouse. The proposed plans are to turn these spaces into a visitor centre and museum, we’re considering various options to make use of the other buildings on site.

Will the plant power my home?

The power generated by the plant is exported to the local electricity distribution network and used locally, though there’s no way to tell exactly which homes it will power.

How tall will the stack be?

The stack is now at its final height of 35m above surrounding ground level.

Will the site discharge water to the River Blackwater?

Only surface water, i.e. rainwater, will be discharged from site. Surface water runoff currently passes through interceptors and is collected in the lagoon on site. The water will be pumped along pipework laid under the access road and into a ditch at Church Road, where it will flow into the River Blackwater. A flood risk assessment has been carried out and demonstrated that the rate of flow will be lower than the natural greenfield run-off rate that existed before the area was quarried. The entire area naturally drains to the river.

The current EA permit amendment application includes this water discharge point. The EA does not regulate surface water discharge, but the existing permit specified that there was no discharge from site, so this is being amended. No procees water from the IWMF will be discharged from site.

Rain that falls in operational areas of the plant where it could become contaminated does not enter the drainage system. It is collected in an underground tank and will be used to quench the hot ash. No process water or contaminated water will be discharged from site.

Will waste be imported from outside the UK?

No. Most of the waste will be from Essex, and some from surrounding counties. The EA permit lists the types of waste the IWMF can accept by EWC (European Waste Catalogue) code. This is a Europe-wide classification system, and does not mean the waste will come from elsewhere in Europe.

How does the plume abatement system work?

Unlike the pollution abatement system, which captures pollutants, the plume abatement system does not capture steam. A steam plume is formed when the hot, moist air from the stack hits the cooler air above and condenses into water vapour – exactly the same as when a kettle boils. The plume abatement system re-heats the plume to 130oC so that it is more buoyant and therefore disperses faster, and so that it also takes longer to cool down so it condenses more slowly. The net effect of this is that by the time it condenses into steam it has spread out far enough that it is no longer visible.

The efficiency of the plume abatement system is very dependent on ambient air conditions, making a visible plume more likely in damp, still air. A visible plume is not an indication of pollution however – it is merely steam.

Is some of the waste you accept still recyclable?

Source separation at kerb side is the most effective way to ensuring what comes to the energy-from-waste facility is non-recyclable. Based on the recent Braintree waste composition analysis, it was estimated that nearly 40% of the waste contained within the grey bin could have been recycled by using the current kerbside recycling options available, and only 1/3 of food waste is being correctly disposed of in the food caddies. Education of the public is the key to ensuring that recyclable waste does not end up being incinerated.