Hydro SludgeScreen's small footprint is ideal where space is critical in existing facilities.
Click here to enlarge imageScreen perforations can be specified between 3 mm and 10 mm, according to requirements and the type of material encountered. While separated solid content is discharged from the screening outlet direct to a container for disposal, sludge can be compacted at a throughput of between 120 m3 and 50 m3 per hour, with a dry solids content of between 1% and 6% respectively.
All at sea
A standard screening model t requires an operating clearance of 6.0 metres in a width of 2.5 metres. This allows several units to be easily mounted on a single platform to provide a compact sludge handling facility. A compact model, requires even less room and is popular for use in applications such as cruise liners, where strict environmental requirements in ports and some coastal waters have placed tight control on discharge at sea. The same robust construction and operational reliability make the smaller model suitable for marine applications where these qualities are key factors.
Southern installation
A typical recent application is at Southern Water’s new £80 million wastewater treatment works for the Margate and Broadstairs catchment area, which is under construction to meet the stringent EU Urban Waste Water Treatment Directive. As well as bringing extensive environmental benefits to the area, it will help local beaches meet the EU Bathing Water Directive and boost the tourist trade.
The new works are being built next to the existing Weatherlees Water Treatment Works (WTW) near Sandwich, which already separately treats wastewater from Ramsgate, Deal and Sandwich. The new works will also take wastewater pumped from Foreness Point and North Foreland WTW via nearly 15 km of new underground pipeline, and will treat 20 million litres of wastewater generated daily by the 93,000 Margate and Broadstairs residents and visitors.
Project engineer Alan Coles of consulting engineers Black and Veatch commented: “The four Hydro SludgeScreens are required because some of the untreated wastewater from particular areas has a high rag content, which needs to be removed before the full treatment process. The screens operate with three screening and one on standby to minimise any downtime. They are installed on a single concrete plinth, over skips which collect the rag for disposal; their small footprint is ideal for a modern treatment works.”
A joint venture consortium between Black & Veatch for design and installation, M&E and process engineering and Costain Construction for civil works, including pipelines and tunneling, is implementing the project.
Currently wastewater from Margate and Broadstairs is screened to remove grit and other debris, before being discharged through long sea outfalls at Foreness Point and North Foreland.
The new process will see the solid waste including rag content removed at Margate Headworks targeted by Hydro’s SludgeScreen. The wastewater will then flow to Weatherlees Hill WTW to under go full treatment, including disinfection with UV light, before being pumped back to Margate WTW for safe release out to sea through the existing long sea outfall.
Author’s Note:
Steve Tansley is Hydro International’s Water & Wastewater Division director based in Ely, Cambridgeshire, England. The company has offices in the UK, USA and Ireland. Contact: +44(0) 800 269371, [email protected] or www.hydro-international.biz