SELCHP Energy Recovery Facility
Annual Performance Report: 2014
Environmental Permit: NP3738SY
Veolia ES SELCHP
Back in 1986, faced with the increasing scarcity and environmental problems of
landfill, the London Boroughs of Lewisham, Southwark and Greenwich came
together to search for a realistic alternative. In 1988, they formed a Consortium -
South East London Combined Heat and Power - from which SELCHP now takes
Bringing together a cross-section of public and private interests, SELCHP's
members included not only the London Boroughs of Lewisham and Greenwich,
but also the Regional Electricity Company and Energy from Waste design,
construction and operation specialists.
From the outset, their approach to the project was based on consultation and co-
operation. The first step was an in-depth feasibility study into the viability of an
Energy Recovery Facility, followed by an Environmental Impact Assessment for
the local community. Addressing concerns over atmospheric emissions, noise,
traffic and visual impact, the E.I.A. was independently assessed on behalf of local
residents, with favourable results.
Conditional Planning Permission was granted in 1990, and required further
studies into noise, landscaping, architecture and traffic in order to satisfy
planner's detailed requirements.
In 1991 site clearance began. A Design and Construct contract was awarded to
Martin Engineering Systems Ltd.
During the winter of 1991/2 SELCHP prepared and publicly registered an
application for an Authorisation under the Integrated Pollution Control
provisions of the Environmental Protection Act, 1990. SELCHP was the first
Energy from Waste scheme in the UK to hold this Authorisation. Also during
1992, SELCHP was awarded an Electricity Generation Licence by the Office of
The plant was commissioned in December 1993 and was officially opened by
HRH the Prince of Wales on 29th November 1994.
Today, SELCHP remains committed to understanding and meeting the needs of
How SELCHP works
SELCHP receives waste from households and some businesses. Waste is tipped
into a bunker, where a crane grabs it and places it into the feed hopper. It then
drops down a feed chute onto a sloped grate, where it is constantly turned to
allow all combustion phases (such as drying, ignition and combustion itself) to
happen simultaneously and a constant high temperature to be maintained.
Ash from the burning process is transferred by an ash discharger and residue
handling system to the ash pit. During the transfer, ferrous metals are removed
for recycling and the remaining ash is sent for reprocessing, where further
ferrous metal and non-ferrous metal extraction takes place, the remaining
aggregate material is recycled into material for road building or construction
Hot gases produced in the combustion process pass
through a water tube boiler where they are cooled; the
heated water is transformed into steam. A turbo-
generator uses the steam to produce electricity for export
to the National Grid.
The gases from the boiler go through a complex flue gas cleaning process,
involving the injection of dilute ammonia solution to reduce nitrogen oxides to
nitrogen and water; lime milk to neutralise acid gases and activated carbon to
absorb heavy metals and any remaining dioxins.
Finally the particulate matter dust is removed from the gas stream by a bag filter
before the cleaned gas is released to air. The resultant material known as Air
Pollution Control Residue (APC residue) is sent for disposal at a licensed
hazardous waste site.
How the power is generated
Steam leaves the boilers at a temperature of 395°C and
pressure of 46 bar, and is fed directly into a single 35 MW
steam turbine generator. The turbine rotates the
generator to produce electricity. Steam from the turbine is
also used to pre-heat the combustion air for the waste
A bank of air cooled condensers condenses the exhaust steam from the turbine
and recycles the water back into the process. Electricity is generated at 11kV and
transformed up to 132kV for export to the London Electricity system which
passes very close to the SELCHP facility.
During normal operation, no supplementary fuel is required to maintain
combustion, just refuse and controlled addition of air.
In 2013 construction of a District heating network was completed at SELCHP.
Over 5 km of underground insulated piping has been laid out of SELCHP into the
neighbouring borough of Southwark. Connected to four boiler houses, fitted with
multiple heat exchangers, supplying 16 residential blocks and 2,500 residents.
Circulating pumps send water in a loop from heat exchangers at SELCHP, heated
by bled steam from the turbine, to each of the boiler houses on the network. This
system is backed up by pre-existing gas boilers located at Clements road boiler
house. Export of heat from SELCHP began in February 2014 and is expected to be
expanded in the coming years.
3. Summary of Plant Operations
SELCHP consists of two incineration lines, each capable of processing
approximately 29 tonnes per hour, allowing for a nominal refuse throughput of
420,000 tonnes per year, but this is dependent on two factors: actual operating
hours and calorific value of the waste being burnt.
The average calorific value of mixed municipal waste for 2014 was ~9226 kJ/Kg.
Plant Operational details for 2014 are included in the table below.
Operating Hours (2 lines)
Incinerator Bottom Ash
Ash residues (known as Incinerator Bottom Ash or IBA) are currently
transported to a processing plant where further ferrous and non-ferrous metal is
recovered and the screened IBA prepared as a substitute aggregate for building
roads and car parks. Only a small percentage is unusable and requires landfilling.
Ferrous metal removed from the IBA is sent to a steel manufacturer for recycling.
Fine particulate matter, known as Air Pollution Control (APC) residue, removed
from the flue gases by the fabric filter is collected and sent to specialised
treatment works where it is used to treat spent acid wastes prior to disposal at a
licensed landfill site.
4. Summary of Plant Emissions
4.1. Emissions to air
Point Source Emissions
Al emissions to air from the 100m high chimney are controlled to meet the
emission limits included in the PPC Permit. The flue gases released into the
atmosphere are continuously monitored.
The following bar chart shows the average annual emissions from Selchp
expressed as average of the Emission Limit Value.
The monitoring equipment was in service during 2014 for 100% of the plant
operating time, with the exception of one day of invalid data for VOC on line 2.
This year operator emission displays were altered to plot negative values in
order to highlight any zero or span check failures. This equipment is stringently
monitored with routine calibration checks and is standardised to BS EN14181
with a full range of standby equipment available should an unexpected failure
Bi-annual monitoring checks of these emissions are carried out by approved
contractors using independent extractive reference methods. Emissions of
metals, dioxins and other substances are also monitored quarterly. Table 1
below shows the pollutants monitored and its frequency. Table 1: Emissions monitoring at Selchp and frequency
Oxides of nitrogen
Dioxins and Furans
All waste processing takes place under cover within buildings to assist in
preventing fugitive emissions of dust and particulates. All operational areas are
fitted with fast acting doors and segregated from processing equipment by
means of floor to ceiling fabric curtains.
The waste bunker is maintained at a negative pressure to prevent odour or dust
from escaping SELCHP’s site perimeter.
4.2. Emissions to Controlled Waters
The on-site drainage has been designed within parameters that take into account
requirements of the Local Planning Authority and the Environment Agency.
Accordingly, the design implemented at SELCHP aims to recycle within the
process as much water as possible.
The gas scrubbing system installed at Selchp does not result in a liquid effluent
and therefore waste water originates only from domestic and cleaning
operations and from the regeneration of the water softener and de-ionising
water treatment plant.
The installation of an evaporative condenser in 2010 resulted in a significant
increase on effluent discharged to sewer during the summer months.
All water entering the SELCHP’s drainage system is collected on a series of
decantation pits, with the aim of reducing solids contents before discharge to the
sewerage system for further treatment.
Monthly samples of effluent are collected and send for analysis to ensure
contamination levels remain within the parameters specified by Thames Water
in the Trade Effluent Discharge Consent. Thames Water also collects samples
independently to verify the quality of the effluent from Selchp.
5. Complaints and queries
The operator maintains a complaints log and any complaint received are
recorded and investigated. Procedure SYS07 of the Veolia Business Management
System (BMS) details the actions to be taken upon receipt of a complaint.
During 2014 a total of four complaints were received. One was received directly
from a member of the public. Three were passed onto site by the Environment
Agency’s PPC Inspector. Three complaints related to odour all of which were
unsubstantiated, it was concluded that the odours reported must originate from
one of the many waste operations in the area and excavations under the railway
arches neighbouring the site. One complaint was regarding a contractors HGV
leaking effluent whilst parked outside the site, said contractors management was
contacted and the issue resolved.
6. Environmental Compliance
Veolia Environmental Services takes great diligence to ensure compliance with
all the conditions of the Environmental Permit at our facilities.
This is achieved through constant monitoring of the process during all of the
stages, with detailed procedures in place to enable trained staff to carry out their
work in an environmentally responsible manner. The plant operates within a
Quality, Health and Safety and Environmental Management System compliant
with ISO 9001, OHSAS 18001 and ISO 14001 and it is independently audited.
During 2014 there were four exceedance of permitted Emission Limit Values
(ELVs) for Carbon Monoxide (CO), caused by a two separate incidents, the failure
of the grate PLC and the simultaneous blockage of two waste feeder rams.
7. Plant Improvements
During 2014 the district heating network, associated heat exchangers, flow
pumps and auxiliary system. The system is presently undergoing a
commissioning programme that is now in its final phases. It is expected that the
supply of useful heat to local residents will improve the efficiency of the plant
from 25% to 35% when the system is fully commissioned. Planning is now
underway to increase the capacity of the system in the coming years to further
increase SELCHP’s energy efficiency.
End of the Report