News Release: Package deal for trickling filters gives guaranteed improvements

Experience of poor distribution affecting media efficiency has led Marley Davenport of Worcester to introduce a package deal that gives water companies and their contractors guaranteed results and peace of mind.

“Many companies don’t appreciate the dramatic difference that poor distribution can make,” says Wastewater Treatment Division Manager David Clarke. “The effectiveness of the filter can be reduced by 30% or more, with media utilisation and retention times significantly reduced. By the time the performance shortfall is discovered, it’s too late and they find themselves embroiled in a three-way dispute with the media and distributor suppliers. Marley Davenport’s policy is to take full responsibility for the total installation by supplying our own design of distributor as well as the media – and we’re prepared to give a full performance guarantee for the complete package.”

Marley Davenport is the leading UK supplier of cross-flow, structured biological media for the treatment of industrial and municipal waste-water. Manufactured in rigid PVC sheet, with corrugations at a 60º angle to the horizontal, it forms an open cross pattern matrix between adjacent sheets.

With 97% open area (compared with 25% for rock), the media is up to three times more efficient than rock. It does not block so has an ‘infinite’ process life, compared with rock filters that can block and pond in about 15 years.

Even distribution on all trickling filters is important and even more essential over modular plastic media. If the distributor fails to give an even wetting rate across the filter bed, its efficiency is impaired, losing some of the operational advantages. After pan tests on several of the industry’s leading distributor suppliers, Marley Davenport came to the conclusion that none really met their ideal distribution profile.

“So we designed our own,” says David Clarke. “We have two designs to meet different market needs.”

The ‘Top discharge, curtain-effect distributor with water turbine drive’ model provides a carefully balanced curtain of water to give optimal wetting of the media. The large diameter top discharge orifices are less prone to blockages and easy to clean and give the ideal wetting for structured plastic media (with as tight as 10% variance to meet optimal requirements). The uncomplicated drive is particularly hard-wearing, with rotation speed being simply controlled by the flow of water to the water turbine.

Alternatively, an open trough distributor with splash plates is a possible solution for roughing filters in enclosed tanks. They have arms discharging through ‘v’ notch weirs onto a splash-plate before hitting the media surface. Marley deems these machines are only suitable for roughing filters as their performance is limited to over 20% on the even wetting rate pan test.

With a reference list of more than 50 cross-flow media installations in the UK, Marley-Davenport is the market leader in this advanced design of trickling filters for both municipal and industrial applications. They have framework agreements with Yorkshire Water and Thames Water and are a key supplier to seven of the other eight English water companies as well as Scottish Water and companies in the Irish republic.

For further details contact David Clarke at Marley Davenport Ltd

Tel: 01905-720200 Fax: 01905-720201

Press enquiries to David Edwards Publicity on

Tel: 01584-831684 Fax: 01584-831601

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