Technology news12

Filtration+Separation July/August 2012

Supernatant recycling project saves water A major regional council in New South Wales, Australia has introduced a supernatant recycling system into the filtration plant in the town water supply, helping to conserve potable water and providing substantial water savings over the long term.

The Bathurst Regional Council recycle system, installed by Ted Wilson & Sons of Blayney using equipment supplied by CST Wastewater Solutions, recovers and disinfects the filter backwash water at the plant. Disinfection of backwash supernatant – clear liquid that collects above sediment – is not widely used in Australia, but can recover up to 10% of raw water supply while also avoiding the need for discharge flows into river systems.Serving a population of about 37,000, Bathurst’s water filtration plant was originally constructed in 1972. Significant upgrades from 1987 to 1994 increased the water treatment capacity from 27 to 60 million litres per day.

The filter backwash water, which is a by-product of the reverse flushing of the sand filters in the filtration plant in order to clear them of sludge, is discharged into the system’s three sludge lagoons, along with sludge from the sedimentation tank. Previously the supernatant from the sludge lagoons was eventually decanted from the lagoons and discharged. The new system involved the construction of a supernatant pumping station and associated pipework to enable the automatic recycling of supernatant from the

sludge lagoons into an in-ground well, and then into the first chamber of the rapid mix tank.The recycle stream will not exceed 10% of the raw water flow through the water treatment system. At the present annual water consumption of about 6000 ML, the wastewater to be recovered could be in the order of 192 ML per year. The overall water to be saved is estimated to be 13,000 ML over 50 years.

Contractor TWS was required to supply and install two submersible motor pumps for the pumping station at the in-ground well, one being a duty pump and the other a standby. Also installed were an electrical switchboard at the pumping well and other associated equipment, including a level control for the pumps and lifting chains for raising and lowering them for maintenance.A Berson UV disinfection system, supplied by CST Wastewater Solutions, was fitted between the pumping station and the rapid mix tank to disinfect the recycled water from the sludge lagoons before returning it to the rapid mix tank. The system fully disinfects up to a flow rate of 60 litres/s and has a variable power control to enable the UV dosage to be adjustable.

The transmissivity (UVT10) of the UV system is 75%, the TSS is less than 10 mg/L and the performance is Log Reductions: >3.1 Log Faecal Coliforms, >2.0 Log E. Coli, which provides effective protozoa destruction.

www.cstwastewater.com

Swift Filters, Inc. has introduced an expanded range of filter elements for the wind power industry. SwiftGreen™ filter elements are specifically engineered for wind turbine gearbox lubrication lines.

They feature a unique reusable machined aluminium bypass valve

assembly which reduces expenses and cuts disposal volume. This bypass valve assembly can be used indefinitely. When it is time to replace a used element, the bypass is removed and inserted into a fresh SwiftGreen element.

SwiftGreen elements can be used as direct replacements for

most major OEM filter elements. All elements employ the latest generation of SwiftGlass ™ Bx(C) ≥ 1000 (per ISO 16889) microfibre glass filter media. This media provides high levels of fluid cleanliness while maintaining low pressure drop characteristics. SwiftGreen filter elements are used on

the return side of hydraulic/lubrication circuits, including those found in wind turbine, power generation, machine tool and many industrial applications. They are interchangeable with filter elements from many original equipment manufacturers.

www.swiftfilters.com

Hydro introduces flow control for sewer systems

Hydro International has launched the Hydro Brake Optimum, a flow control for surface water, foul and combined sewer systems. The Hydro-Brake Optimum was officially launched at the IFAT show, which took place recently in Munich, Germany.

The Hydro-Brake Optimum unit sizing enables fine-tuning according to the site priorities. For example, it may be important to maximise hydraulic performance or to choose a more compact design to account for site constraints such as pipe diameter or chamber retrofit. It can balance flow rates and surface water storage requirements to the conditions of a development site.

The company says that sites using Hydro-Brake Optimum will need up to 15% less storage than if an alternative vortex flow control were used.

The system features adjustable inlet plates which can provide up to 20% alteration in the forward flow rate and up to 20% larger clearances than other flow controls. It is made of high grade stainless steel and includes lugs, push-fit spigots, flat or curved mounting plates, penstock or slide mounts and removable units. The Hydro-Brake Optimum is also available pre-fitted to a purpose-built pre-cast reinforced concrete chamber.

www.hydro-int.com

The Hydro Brake Optimum.

Expanded line of wind turbine filter elements

FISE_4_JA_Technology News 12 01-08-12 09:00:37