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Wastewater Project of the Year

For the wastewater project, commissioned during 2021, that shows the greatest innovation in terms of optimising its physical or environmental footprint.

Recolab, Sweden

What is it?

A 2,300 p.e. recovery system in the Oceanhamnen district of the Swedish city of Helsingborg. It pioneers an energy-efficient, circular sanitation process that source-separates blackwater, greywater and food waste through separate pipelines to recover nutrients, produce biogas and recycle wastewater to drinking water quality.

Who is involved?

This project was commissioned by intermunicipal utility Nordvästra Skånes Vatten och Avlopp (NSVA) and designed by DeSah, which also installed the heat recovery, black water and food waste digestion, greywater and sludge treatment systems. NX Filtration provided nanofiltration (NF) membranes and Jotem Waterbehandeling provided NF skids.

What makes it special?

Recolab is the largest source-separated sanitation plant in the world using circular treatment to efficiently recycle greywater, blackwater and food waste. Greywater and food waste are collected by two gravity sewers while blackwater is collected with an efficient vacuum sewer, which reduces water consumption for the system as a whole by at least 25%.

The project sets the standard for sustainable, circular water and waste management at a local level. Treated effluent passes through a nanofiltration system that removes micropollutants and nutrients which are then sent to a factory to produce fertiliser pellets, while biogas energy is returned back to the community for use in district heating and treated water is directed to a nearby swimming pool.


By producing biogas and fertiliser, and recycling 80% of greywater to potable standard, the project contributes to lower eutrophication, increased renewable energy output and lower water consumption. The plant also provides a model for a collaborative approach to domestic waste management between water, wastewater and energy utilities that maximises environmental sustainability.

Joint Distinction

Bahr el-Baqar WWTP, Egypt

What is it?

A colossal 5.6 million m3/d tertiary wastewater treatment and sludge handling plant in Sinai, Egypt, taking polluted water from the Bahr el-Baqar drain (a combination of industrial effluent, sewage and agricultural runoff). Water is treated with a combination of coagulation, flocculation, settling, filtration and disinfection before being transported under the Suez Canal and reused for irrigation in newly-created agricultural land. The total value of the project was in the region of $739 million.

Who is involved?

The project was delivered by a contracting team comprising Orascom Construction and Arab Contractors on behalf of the client, the Ministry of Defense’s military works department. Acciona Agua carried out process engineering and installation support for installation of electromechanical works, while Khatib & Alami was lead consultant for the project.

What makes it special?

The scale of the project is difficult to encompass – it is by some measures the largest wastewater treatment plant in the world, and proves that investment in mega-scale water infrastructure projects can have an immediate for the environment and water resources.

The project strikes a huge blow against pollution of natural areas from the effluent produced by Egypt’s huge cities, industries and agricultural areas. Previously, polluted water in the Bahr el-Baqar drain had the potential to affect fish farms and agricultural land around the Manzala Lake where it discharged, with proportions of heavy metals in the water a particular worry.


The water produced by the project will support the creation of 140,000 hectares of new agricultural land without the need to further tax water supplies – a massive boost for Egypt in a world where both sources of food and water are looking increasingly unreliable.

Rialto bioenergy facility, USA

What is it?

A $185 million privately owned and operated waste-to-energy project located in San Bernardino County, California, that converts up to 1,000 tons a day of wastewater biosolids and food waste into renewable natural gas and agricultural fertiliser.

Who is involved?

Anaergia developed, financed, and operates the merchant bioenergy facility. Feedstock is taken from municipal clients in southern California such as the City of Rialto and the Orange County Sanitation District, while offtakers for the produced gas include Southern California Gas. First State Investments acquired a 49% equity stake in the project in 2020. Anaergia partnered with W.M. Lyles Co. as the design-build contractor while GHD served as design consultant. Fibracast membranes were used to treat and recycle all process water on-site.

What makes it special?

The largest organic waste-to-energy project in North America, the Rialto bioenergy facility is designed to produce up to 985,000 MMBTU of renewable natural gas each year. By reducing the landfilling of organic waste and producing a carbon-negative fuel, the project’s net carbon dioxide emissions reduction is approximately 220,000 metric tons annually – equivalent to taking 47,500 cars off the road.

The project utilises Anaergia’s proprietary organic waste extraction process that creates high-quality feed material for its advanced anaerobic digestion technology. These digesters are up to three times more efficient than conventional alternatives, and in addition to renewable natural gas, produce high-quality “Class A” fertiliser for California’s rich farmlands.


In spite of fresh challenges wrought by the COVID-19 pandemic – such as reduced feedstock availability – Anaergia is making a success of the failed sludge-to-energy venture it acquired from the bankrupt EnerTech in 2013. With California law now requiring a wholesale statewide reduction in the volumes of organic waste and biosolids sent to landfill, the facility will serve as a replicable blueprint for years to come.