Nominate/Submit Case Studies

Become a Featured Company

Job Board

Southern Water

Southern Water provides water supply and wastewater treatment services across 4,450 square kilometres from East Kent, through parts of Sussex, to Hampshire and the Isle of Wight.

Raw water is taken from aquifers (70%), rivers (23%) and from storage reservoirs (7%), and each day the company supplies 576 million litres of drinking water from 95 water treatment works along 13,700 km of water mains. The company also operates a sewer network of more than 39,200 km, and every day the company treats and recycles 1.3 billion litres of wastewater at 370 treatment works.

Southampton Shellfish Scheme (2024)

An £85m scheme that applied innovative modelling to optimise storm volumes and adopted the new approach to final effluent disinfection

Southern Water Maintenance Transformation (2024)

Breaking the reactive cycle to move towards a proactive future

Goddards Green WwTW (2023)

Goddards Green Wastewater Treatment Works (WwTW) is a Sludge Treatment Centre (STC) located near Burgess Hill in West Sussex. The catchment serves the towns of Burgess Hill, Hassocks, Hurstpierpoint and surrounding villages, providing for 54,789 people. The project implements an innovative approach to mitigate the likely odour from the processes at the WwTW to prevent […]

Isle of Wight South Strategic Optimisation (2023)

Forming part of Southern Water’s (SW) Hampshire supply region, the Isle of Wight (IoW) is located just off the south coast of England and is divided into two water distribution zones (WDZ), namely IoW North and IoW South. The IoW South comprises major towns of Ryde, Sandown, Shanklin and Ventnor with multiple villages and more […]

Southern Water WINEP (2023)

To ensure compliance with tighter Environment Agency permits for phosphorus removal, the number of phosphorus reduction schemes have quadrupled since AMP5 and is seen by some as one of the biggest challenges ever to face the water industry. The Water Industry National Environment Programme (WINEP) is a programme of actions that water companies are required […]

Hailsham South WwTW (2022)

The town of Hailsham in East Sussex has been experiencing significant housing growth in recent years. To accommodate local housebuilding targets and protect the environment, Southern Water has invested £30m to upgrade the Hailsham North and Hailsham South Wastewater Treatment Works (WwTWs) using innovative technology. Upgrading these works was necessary to comply with a stricter […]

Southern Water Eel Screens Programme - Construction (2022)

The Eels (England and Wales) Regulations 2009 requires an eel screen to be installed within a diversion structure capable of allowing at least 20m3 of abstraction in a 24-hour period. The focus of this programme is to protect a threatened species of fish, brook lamprey (Lampetra planeri). This eel-like ancient fish is rare in the UK […]

Hawkhurst South WwTW (2021)

The NEP Quality drivers for the Southern Water’s Hawkhurst South WTW are to meet the new iron and total phosphorus discharge permit limits by 31/12/2021, a tightened ammonia permit by 31/03/2025, and to maintain compliance with all aspects of the current discharge permit at lowest whole life cost. In addition, the population equivalent is set […]

Telscombe Lower Portobello PS & Screening Works (2021)

The original treatment works was built in the 1970s in an area carved out of the cliff face. It comprised a screening plant for grit and fat removal, before flows are pumped via a hand-dug long sea outfall 2.5km out to sea. This outfall replaced the original Victorian short sea outfall built in 1874, although […]

East Worthing WwTW (2020)

Located close to the English Channel, East Worthing WwTW serves a population of 140,000 in a largely urbanised area in West Sussex. In peak wet weather conditions, up to 71 million litres can flow through the site in a day. Due to the urban nature of the catchment, and some large and relatively shallow gradient […]

Southern Water Eel Screens Programme - Design (2020)

The Eels Regulations 2009 require an eel screen to be installed within a diversion structure capable of allowing at least 20m3 of abstraction in a 24-hour period. The focus of this programme is to protect a threatened species of fish, brook lamprey (Lampetra planeri). This eel-like ancient fish is rare in the UK and ranges […]

Woolston WwT Scheme - Part 5 (2020)

In October 2020, the finishing touches were undertaken at Woolston Wastewater Treatment Works, completing Southern Water’s £100m scheme to transform its works in Southampton, Hampshire. From the waterside, the new age space-like silver cladding that dominates the site is a much different picture from how the site has looked over the last few years when […]

Otterbourne WTW (2019)

Otterbourne WSW is a critical site, located between Southampton and Winchester, supplying water to the surrounding area to a total of around 250,000 homes. Otterbourne was originally constructed in 1939, with extensions to the works being constructed in 1949 and 1958. The works treats borehole and river water which supply two independent treatment streams. The […]

Scaynes Hill WwTW (2019)

Scaynes Hill Wastewater Treatment Works serves a population of approximately 38,000 from Haywards Heath and surrounding areas in West Sussex, with capacity to treat up to 337 l/s of incoming wastewater flow. The treatment works also receives imported cess via tanker from customers not connected to the mains drainage system, plus liquid sludge via tanker […]

Thanet Sewer Rehabilitation Scheme - Phase 2 (2019)

Southern Water has started the second phase of its major upgrade of the 100-year-old sewer network across Thanet, Kent. Representing an investment of circa £100m over AMPs 5, 6 and 7, the upgrade aims to maintain the integrity of the sewers, reduce the risk of flooding and protect the environment and chalk aquifer that spans […]

Woolston WwT Scheme - Part 4 (2019)

Woolston WwTW uses a conventional activated sludge plant (ASP), built in 1966, treating sewage flows from part of the Southampton conurbation, serving a population of approximately 62,000 people. The site occupies an area of 1.26 hectares. The existing sewerage system which feeds into the WwTW collects both wastewater and stormwater from the Woolston catchment area. […]

Ashford WwTW Sludge Treatment Centre (2018)

Ashford Wastewater Treatment Works is located in Kent alongside the M20 motorway, near the River Great Stour to the South of the Kent Downs (Area of Natural Beauty). The Town of Ashford has a population of approximately 110,000 people. The WwTW serves Ashford and surrounding areas and is supplied by five local pumping stations taking […]

Fort Cumberland Sea Defences (2018)

Three of Southern Water’s underground storm tanks next to the historical Fort Cumberland have played a crucial part in helping to prevent homes in Portsmouth from sewage flooding during stormy weather. Although redundant, the old sea defences protecting the tanks needed replacing and strengthening, and ongoing maintenance is essential to preventing their contents polluting the […]

Woolston WwT Scheme - Part 3 (2018)

Built in 1966, Woolston Wastewater Treatment Works (WwTW) uses a conventional Activated Sludge Plant (ASP) to treat sewage flows from part of the Southampton conurbation. Serving a population of approximately 62,000, the site occupies an area of 1.26 hectares. The existing sewerage system which feeds into the WwTW collects both wastewater and stormwater from the […]

East Worthing WwTW (2017)

East Worthing WwTW in Lancing serves the Worthing and Sompting catchments in West Sussex, located on the south coast of England. The works provides treatment capacity to a population equivalent of 136,000, which is expected to rise to 155,000 by 2030. East Worthing WwTW is an activated sludge plant providing secondary treatment for flows up […]

Foreness Point Intertidal Habitat Enhancement Plan (2017)

In November 2016, Southern Water commissioned Mott MacDonald to conduct a study to examine the opportunities for devising possible habitat enhancement options via an Intertidal Habitat Enhancement Plan (IHEP). The aim of the study was to identify enhancement options that would be available to Southern Water to support coastal biodiversity in the intertidal zone adjacent […]

Margate & Broadstairs Wastewater Pumping Stations (2017)

In 2008, Southern Water completed significant improvements to the wastewater treatment infrastructure serving the North Thanet catchments of Margate and Broadstairs to meet the requirements of the Urban Waste Water Treatment Directive. The existing marine head works at Joss Bay, Broadstairs and at North Foreland, Margate were upgraded to process screened flows and remove grit, […]

Woolmans Wood Phase 2 (2017)

Between 2011 to 2013, Southern Water invested £14m replacing old water mains in the Chatham, Gillingham and Rochester. An additional £8 million is now being invested to replace a further 28km of 85-year-old water mains and service pipes to further improve water supply pipes and reduce the risk of discoloured water. The Chatham supply zone […]

Woolston WwT Scheme - Part 2 (2017)

Built in 1966, Southern Water’s Woolston WwTW uses conventional activated sludge plant (ASP) to treat sewage flows from part of the Southampton conurbation, serving a population of approximately 62,000 people. The site occupies an area of 1.26 hectares. The existing sewerage system which feeds into the WwTW collects both wastewater and stormwater from the Woolston […]

Botley Park Trunk Sewer (2016)

The Ashill Group is building a development of 1,400 new homes and businesses to the east of Southampton on Botley Park Golf Course and the adjacent farmland. As the local sewerage undertaker, it is Southern Water’s statutory duty to connect this development to its foul sewer network. Following initial investigations, Southern Water confirmed that the […]

Hastings Bathing Water Improvement Scheme (2016)

Hastings Beach on the southern coast of the UK was identified at risk of failing the European Union revised Bathing Water Directive. If the bathing water failed, Hastings Borough Council (HBC) would be legally required to put up signs warning the public of poor water quality. MWH (now Stantec UK) targeted ‘high beneficial’ interventions by […]

Military Road Rising Main Replacement Scheme (2016)

Ramsgate is a seaside town on the North East Kent coast; its coastline and harbour attracts thousands of tourists each year. The wastewater from the town is pumped to Weatherlees Hill Wastewater Treatment Works, situated inland over 6km away. Over a 15-year period the pipeline had suffered a number of bursts and needed replacing as […]

Swalecliffe Habitat Resilience Plan (2016)

Resilience is a key metric when developing, improving and managing habitat systems and their associated ecology across diverse coastal and urban environments where wastewater treatment plants reside. The study site for this paper is located within the Thanet Coast Biodiversity Opportunity Area (BOA) and Site of Special Scientific Interest (SSSI) Impact Risk Zone for the […]

Woolston WwT Scheme - Part 1 (2016)

Construction works are now in their second year on Southern Water’s £63 million environmental improvement scheme to redevelop and completely modernise Woolston WwTW. (The first year of the Woolston WwT Scheme was detailed in the 2015 edition of UK Water Projects). The existing works uses a conventional activated sludge plant (ASP), built in 1966, treating […]

Chichester WwTW (2015)

£2m improvement scheme to significantly improve the quality of stormwater discharges

Portsmouth FAS - Early Warning Scheme (2015)

Managing storm flows using the an early warning system moving from ‘just in case’ to ‘just in time’

Portsmouth FAS - Sewer Network Improvements (2015)

Part of Southern Water’s £50m programme of improvements to the sewer network in Portsmouth

Thanet Sewer Rehabilitation Scheme (2015)

Using specialist and innovative techniques to renovate sewers built in chalk tunnels by the Victorians

Universal Metering Programme (2015)

As its pioneering programme to install nearly 500,000 water meters draws to a close, Southern Water reports substantial benefits for company and customers

Woolston WwT Scheme (2015)

Work has started on a £63m environmental improvement scheme to redevelop and completely modernise Woolston WwTW. The existing works uses a conventional activated sludge plant (ASP), built in 1966, treating sewage flows from part of the Southampton conurbation, serving a population of approximately 62,000 people. The site occupies an area of 1.26 hectares. The existing […]

Ashford WwTW (2014)

Ashford WwTW is located approximately 15 miles north-west of Folkestone in Kent. Prior to Southern Water’s £12.6m expansion, the works served a population equivalent of 100,000 people. Starting in June 2012, this extensive project will ensure that the site continues to serve the growing population of this busy catchment, which is forecast to rise to […]

Brighton & Hove WwTW (2014)

Peacehaven WwTW – handover and completion of the ‘Cleaner Seas for Sussex’ project

Budds Farm WwTW (2014)

Reducing the risk of emergency releases of wastewater into Langstone Harbour by increasing performance

Eastney Pumping Station (2014)

Upgrading an obsolete system that is no longer supported by the vendors

Fort Cumberland Storm Tank (2014)

A study of optimisation using computational fluid dynamics

Hardham WSW (2014)

Washwater treatment and sludge processing system improvements

Millbrook WwTW (2014)

Overcoming challenges with careful planning to deliver a robust process solution & reduced nutrient emissions

Morestead Road (Winchester) WwTW (2014)

Southern Water doubles wastewater treatment capacity at Winchester to provide for future population growth

Peel Common STW (2014)

Replacement of inlet works and upgrades to sludge dewatering facilities at a WwTW near Portsmouth

Ashford WwTW (2013)

Ashford is located approximately 15 miles north-west of Folkestone in Kent. The wastewater treatment works currently serves a population equivalent (PE) of 100,000 which is forecast to increase to 130,000 by 2020. Southern Water is investing £12.6m to upgrade and modify the process units at Ashford WwTW to meet future increases in flows and loads […]

Brighton & Hove WwTW (2013)

Peacehaven WwTW – commissioning to operations

Combined Heat & Power (2013)

Generating electricity from biogas at key Southern Water sites

Overton WSW - Nitrate Removal Plant (2013)

Integration of ion exchange technology to counteract increasing nitrate concentration in source aquifer

Pennington WwTW (2013)

Delivering environmental improvements and increasing capacity to meet population growth

River Medina Rising Main Crossing (2013)

£1.2m project to renew a strategically important rising main on the Isle of Wight

Botany Bay Road Sewer Improvement Scheme (2012)

Replacement sewer reduces potential flooding risk in city suburb

Brighton & Hove WwTW (2012)

£300 million environmental improvement scheme to bring cleaner seas to Sussex

Chatham Mains Replacement (2012)

48.5km of water mains replacement to reduce the risk of discoloured water

Mains Flushing Programme (2012)

Southern Water’s water pipe flushing to remove iron deposits and other unwanted material

Staplefield WwTW (2012)

An example of the challenges faced by water companies in addressing consenting issues on small rural works

AMP5 Overview (2011)

£1.75bn investment to meet the 2010-2015 business and regulatory objectives

Brighton & Hove WwTW (2011)

Constructing one of the largest green roofs in Europe to bring cleaner seas to Sussex

Hardham Water Resource Project (2011)

Water abstraction from the River Arun safeguards supplies to customers in Sussex

Universal Metering Programme (2011)

‘Intelligent’ water meters employ Automatic Meter Reading (AMR) technology

Ashford Sludge Treatment Centre (2010)

Improvements to meet anticipated population rise to 150,000 by 2020

Brighton & Hove WwTW (2010)

Over 250,000 people to benefit from a modern wastewater treatment system

Brighton Mains (2010)

£15.5 million project to replace 57km of Victorian water mains in Brighton

Canterbury Sewerage Scheme (2010)

Innovative solution to provide additional capacity to the sewerage system

Chichester WwTW (2010)

Biological nutrient removal plant

Eastney Pumping Station (2010)

£20m ten-point plan to protect Portsmouth from flooding

Fullerton STW (2010)

Upgrade to a major wastewater treatment plant for Andover, Hampshire

Maidstone - Woolley Road SuDS (2010)

Flood protection in Maidstone has less impact on the environment

Brighton Mains (2008)

£15.5 million project to replace 56.6km of Victorian water mains

Budds Farm WwTW (2008)

Combined heat and power project: Getting the most out of recycling waste

Cross Solent Water Main Replacement (2008)

New underwater pipelines bring more water to Isle of Wight

Peel Common STW (2008)

One of six schemes have nitrogen removal as common objective

Budds Farm WwTW (2007)

Nitrogen removal scheme

New Romney & Greatstone First Time Sewerage Scheme (2007)

Vacuum station built in former car park

Portslade (South Street) FAS (2007)

South Street flood prevention scheme

Sandown Water Supply Works (2007)

Increasing overall capacity of works and improving process

Throwley & Kettle Hill Groundwater Sources (2007)

Groundwater sources in Area of Natural Beauty

Weald Road Tunnel (2007)

Tunnelling work carried out underneath active residential properties

Margate & Broadstairs WwT Scheme (2006)

Brings benefits to residents, visitors & marine environment

Faversham Creek CSO Wildlife Protection (2005)

£24,000 scheme to make way for new rising main

Learning lessons adds value for Southern Water

Lewes Sewerage Improvement Scheme (2005)

£14m urban drainage improvements project for historic town

Otterbourne & Arundel Water Supply (2005)

Removal of cryptosporidium risk

£100m upgrade & refurbishing of more than 50 WwTWs

3 example upgrades within five year £120 million investments

North Sussex Bulk Supply & Bewl-Darwell (2004)

Water companies invest £31m to safeguard resources

Bexhill & Hastings WwTW (2003)

Historic setting for £100m environmental improvement project

CSO Programme (2003)

186 intermittent discharges to be improved in K3 period

Foord Valley (Folkestone) Flood Alleviation Scheme (2003)

£5.5m flood alleviation scheme after 1 in 600 years storm

Frittenden WwTW (2003)

£1.2m plant fabricated off-site delivered to village on five lorries

Mile Oak & Goldstone WTW (2003)

£5.7m nitrate reduction plant for two critical supply sources

Sandown WwTW (2003)

Compact plant on brownfield site serves IOW

Testwood WTW (2003)

£5.8 million upgrade improves efficiency, safety, water quality

Dover & Folkestone WwTW Upgrade (2002)

Upgrade to full secondary treatment with provision for UV

Eastbourne WwTW (2002)

Adding secondary treatment – ‘like building a ship in a bottle’

Hastings WwTW (2002)

Final phase of £100m environmental scheme

Shoreham WwTW (2002)

New compact treatment system used in £11m upgrade

Worthing WwTW (2002)

£17m upgrade improves coastal water quality