Wastewater Collection Systems

The 91^st Avenue WWTP Chlorination Improvements project involved the replacement of a 120-ton bulk chlorine system with a system consisting of 32 one-ton chlorine cylinders.  The plant has a treatment capacity exceeding 180 mgd. The existing chlorination equipment and piping was replaced while the plant was in full and normal operating condition. The plant’s treated effluent is used at the Tres Rios Wetlands and as cooling water for the Palo Verde Nuclear Generating Station.

The project also involved the development and coordination of the Maintenance of Plant Operation (MOPO) procedures. The chlorination of the plant effluent had to be maintained at all times during construction. The project also included building structural, electrical, and HVAC modifications. The equipment installed included the following:

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In May 2005, floods affected the northern region of Tauranga city resulting in the inundation of many properties.  In response to the flooding, Tauranga City Council implemented a city-wide Storm Recovery Programme. A major component of the Storm Recovery Programme was the Aerodrome Road Stormwater Catchment Upgrade, which began in September 2006 with capital works forecast at $5.6 million.

The Aerodrome Road stormwater catchment is widespread, covering 26 hectares in Mount Maunganui.  The environment is particularly complex as the catchment’s drainage flowed west via open drains and pipelines between buildings on private property to the harbour at the Port of Tauranga.  As this drainage was in a developed area, the upgrade could not be realistically undertaken without disruption to existing property owners and occupiers, and at a considerable cost to ratepayers.

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Managing stormwater is one of Auckland City's many activities. Auckland City aims to protect Auckland's unique and valued environment and allow for future urban growth. It is Auckland City's job to assist Auckland's residents to make sure stormwater is managed properly on their land, and to safely remove stormwater across the city.

Auckland Transport’s drainage assets consist of approximately 27,500 catchpits, 2,300 soakholes and 550 manholes within Auckland’s central city and the Hauraki Gulf islands.  The condition and performance of these structures is critical not only to the city’s wider drainage and reticulation system, but also to the efficiency, safety and reliability of the transportation network.

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With the growth of Auckland City, the combined stormwater/wastewater system was exceeding capacity during rainfall events, resulting in pollution of the Waitemata Harbour. A conventional project model could not guarantee the level of service that Metrowater wanted for their customers during the separation process so they decided on an Alliance model – one that was strongly customer focussed. The project goal of cleaning up Auckland’s harbour was a philosophy of shared ownership and responsibility reflected in the principle – "it's ours".

Metrowater is Auckland City's water and wastewater utility and was established by Auckland City Council to provide water and wastewater services to over 142,000 homes and businesses, reaching 420,000 people across Auckland City.  The area of operation covers 153 square kilometres with a water and wastewater network of more than 3,600 km of pipes. Metrowater’s expectation is that their customers receive the highest quality, reliable water supply possible and that Auckland City’s wastewater networks are managed in a cost effective, environmentally sound and sustainable manner.

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GHD played a key role in the new Coffs Harbour Water Reclamation Plant, which is capable of producing reclaimed water of a standard suitable for irrigation.

Our team completed the process, hydraulic and civil design of the plant, in partnership with the Coffs Infrastructure Alliance, which comprised the alliance partners Abigroup, John Holland and Coffs Harbour City Council.

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GHD plays a leading role in securing Dubai’s current and future water requirements.

Our team in the Middle East has completed preliminary engineering work on the Jebel Ali Free Zone (JAFZA) Utility project to provide water infrastructure to an area of 8500ha that includes the JAFZA Free Trade Zone, Technopark and downtown Jebel Ali. These precincts comprise both greenfield and existing development with industrial, commercial and residential land uses.

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GHD has helped the town of Easton in Maryland, USA, implement the first Enhanced Nutrient Removal Wastewater Treatment facility funded by the Chesapeake Bay Restoration program.

The plant was designed to meet new National Pollutant Discharge Elimination System limits of 4.0 mg/l Total Nitrogen (TN) and 0.3 mg/l Total Phosphorus (TP) on an annual average basis. It serves the Town of Easton and is designed to treat an average daily flow of 4.0 mgd, expandable in the future to 6.0 mgd.

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Watercare Services Limited engaged GHD as their technical adviser for the provision of a public collection network and wastewater treatment system for the small coastal community of Kawakawa Bay (Auckland, New Zealand).

Situated south-east of Auckland, Kawakawa Bay had experienced a high failure rate of the local on-site wastewater systems. The recommended option was a vacuum operated collection system followed by a Membrane Bio Reactor (MBR) treatment process. The treatment plant consists of inlet works, process tanks, and the membrane separation system. A seasonal lagoon balances the influent flow, and a treated water operational lagoon stores and balances flows for effluent disposed using rotating sprinklers in the nearby forest. The wastewater scheme was commissioned 2011. Public health issues have been reduced, and the quality of the surrounding marine environment has improved through the reduction in effluent contamination of the receiving areas.

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Ingeniería conceptual manejo integral de aguas de drenaje de mina - Región de O'Higgins, Chile.

Codelco-Chile, División El Teniente contrató los servicios de GHD para realizar un estudio de ingeniería conceptual para el manejo de las aguas de drenaje de mina.  En este proyecto participaron en forma conjunta los equipos de las áreas de agua y medio ambiente. El objetivo principal fue implementar una solución integral y sustentable para las descargas de las aguas de drenaje de la mina con el fin de dar cumplimiento al marco regulatorio ambiental vigente. Estas descargas provienen de los aportes de aguas subterráneas, infiltraciones de aguas de deshielo y/o aguas lluvia que ingresan a la mina a través de la superficie del cráter. Luego de su paso a través de la roca y de la faena minera, cuentan con un alto contenido de metales, sulfatos y condiciones de acidez que pueden afectar al río Coya, ubicado en la Región de O'Higgins, aproximadamente 120 km al sur de Santiago. Los principales alcances considerados en el proyecto fueron: análisis de riesgos ambientales y sociales, intercepción de aguas antes de su ingreso a la mina, segregación de aguas ácidas al interior de la mina, tratamiento de aguas de drenaje de mina, transporte y recirculación de aguas de drenaje de mina, y embalse regulador de aguas de drenaje.

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The community of Mission Beach, between Townsville and Cairns, now has a modern sewerage system after Cardwell Shire Council engaged GHD to project manage the installation of a complete sewage reticulation network and treatment plant upgrade.

The scheme involves over 32km of reticulation and collection system, 11 pump stations and 45km of rising mains, and is located in sandy, high groundwater conditions in developed residential precincts.

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GHD designed this 150,000 gpd (570,000 L/d) WWTF using a sequencing batch reactor-activated sludge process, which included nitrification-denitrification to achieve a class A⁺ finished effluent.

Elements of design included influent flow metering, a fully enclosed duplex pump station, fine screens, first and second stage aeration for nitrification and denitrification, clarification, and aerobic digestion.  Sludge handling was accomplished through centrifuge dewatering.  Odor and noise abatement was incorporated through the total enclosure of headworks screens, aeration and clarification elements, sludge processing, air blowers, and electrical system inside a building.  The design included a bulk liquid sodium hypochlorite disinfection system for the final stage of treatment.  Finished effluent is used to irrigate golf turf.

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GHD was commissioned to design and engineer a trade waste rising main replacement for the SPC Ardmona fruit processing plant in Victoria.

This pipe was to be replaced due to the degradation of the existing pipeline, excessive ground movement and pipeline failures. Goulburn Valley Water Authority will take over ownership of the main from SPC-Ardmona on successful replacement of the entire pipeline from the factory to the outfall tower.

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Sydney Water in partnership with Sydney Water Corporation, John Holland, Thompson Controls, and GHD delivered the $60 million Rouse Hill Recycled Water Plant – stage two amplification project. This is the Southern Hemisphere’s largest residential water recycling scheme.

Initiated in September 2006, the project doubled the capacity of the existing waste water treatment plant to 27 million litres a day and increased the recycled water capacity to 4.7 billion litres a year (this will supply 36,000 homes in the local community at project completion).

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The new Scorpion Bay Marina is located on the west coast of Lake Pleasant.  The marina includes more than 300 boat slips, a boat pumping station, restrooms, showers, and a restaurant.  GHD provided permitting, design, and construction services for the marina’s wastewater treatment plant.  The plant is an activated sludge facility with extended aeration and de-nitrification capability.  It also includes sand filtration, chlorination and de-chlorination, and an aerobic sludge digester.  All of the reclaimed water produced by the plant is stored in an above-ground steel reservoir and pumped through the marina’s irrigation system. 

To enable the marina to open prior to the completion of the treatment plant, GHD also designed a temporary vault and haul system that included instrumentation and controls, secondary containment, an aeration system and an odor control air scrubber.  In addition, GHD provided design and construction support for the marina’s wastewater pumping system, which uses peristaltic pumps to move flows from boats, restrooms, and the restaurant to a common wet well where they are then pumped using grinder pumps off of the marina and to the treatment facility. 

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Following the amalgamation of eight local government boundaries, GHD was commissioned to develop a high-level strategy for the Toowoomba Regional Council for the planning of wastewater treatment plants and effluent reuse.

The study included a review of previous planning studies completed by the former local authorities, a population review and a look at loadings. A brief assessment of the status of the area’s existing sewage treatment plants was undertaken to determine their capacity and if they should remain as a stand-alone system or be integrated with other systems.

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The Washington Suburban Sanitary Commission (WSSC) appointed GHD to lead the provision of asset management services in support of master planning and enterprise resource planning initiatives.

WSSC is the eighth largest water and wastewater utility in the USA, owning USD$12 billion of infrastructure assets. While instituting a range of short-term measures to combat the increasing incidence of water main breaks and leaks, WSSC is also taking a long-range strategic approach to address the growing challenge of ageing infrastructure.

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As part of the City of Scottsdale’s broader water optimization program, the city turned to GHD to update its wastewater model. The objective was to reflect recent billing data and flow metering results as well as updated development plans and capital improvement projects.

GHD has a long history with the city, having designed more than 50 water projects within the region.

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