WASTEWATER RESEARCH AND INDUSTRY SUPPORT FORUM
Meeting 25th March 2015
This was the Forum’s 55th meeting and the last to be chaired by Andrezj Nowosielski who is leaving the Environment Agency to join an organisation called Water and Sanitation for the Urban Poor. Andrezj has been an enthusiastic chairman; he will be succeeded by Barrie Howe, also EA. Again the Forum met in CIWEM’s HQ, 106-109 Saffron Hill, London.
Reports from topic leads
Flow & Quality - Oliver Grievson, Anglian Water
Catchment Scale Impacts - Mike Hutchins, CEH [for Richard Williams]
New Drivers and Legislation - Andrezj Nowosielski, EA
A roundup of members’ research included the following:
Mike Hutchins, CEH [for Richard Williams]
Gordon Jones – FWR
Andy Eadon – Regional Flood & Coastal Committee
Simon Tait – Sheffield University
Andrezj Nowosielski – EA
Technical Presentations with members of CIWEM’s Wastewater Management Panel
Nutrient sources and fates in rural streams; can agri-environment schemes improve water quality? - Mike Bowes, CEH
This described a farm-scale experiment into the effectiveness of grass margins, which earn agri-environment credits, for reducing phosphate in streams. The site is on clay textured soil in Buckinghamshire. The experiment compared 6m wide margins with 6m margins sown with phosphate accumulating plants and with 30m margins with phosphate accumulating plants. The largest phosphate loss from fields is “particulate-P”, which is phosphate attached to soil particles, the objective of the margins is to trap soil particles and filter the runoff water.
The design comprised 4 replicate treatment blocks. The width of margin had no effect on the concentration of soluble reactive phosphate measured in the stream and neither did the seed mixture, which indicated that 6m was adequate. However, there was an unexpected finding; even in this rural area with no conurbations upstream, 200 mgSRP/L (soluble reactive phosphate) or more was found at some of the blocks and this was accompanied by boron, which showed that septic tank and misconnection contributions overwhelmed the diffuse inputs from farmland (perborate is a whitener in some detergents). Reducing sediment runoff into streams is useful but grass margins cannot solve the SRP issue when there are other, greater, hitherto unrecognised sources. By coincidence, Bob Middleton from Natural England told the CIWEM Annual Conference about the Catchment Sensitive Farming programme, which he described as “highly targeted and focused” but septic tanks and misconnections are not included in the targets. They might make five or more visits to a farm but until now have not checked to see whether these “stable doors” are open. It would be very useful if the results of CEH’s work caused NE to amend the focus and targeting of CSF.
Intelligent Wastewater Networks - Oliver Grieveson, Anglian Water
Oliver’s report was based on the CIWEM “Value of Intelligence in the Wastewater Network” conference that was held on 18th February. It was a sell-out with a waiting list. Most WaSCs are considering smart sewerage. Commercially available FDT Flow Detection Transducer for CSO & SSO Event Duration Monitoring and BDT Blocked Sewer Detection Transducers are increasing the practicability. Barcelona, Berlin, Copenhagen and Paris are four examples of smart sewer networks; Paris operates its sewerage as six networks. They have found that actively managing sewer weir heights, etc. to flush sediments reduces CSO activations at 25% of the capital cost of building tank sewers but would this strategy be compatible with the UK’s very prescriptive approach to consenting CSOs? There were signs for hope that the UK’s “culture” around wastewater management might be evolving but depressing signals about how far it has to go. AMP6 and Totex might herald more post-project appraisal because the name of the game will change from just building stuff to managing the businesses for best whole life cost but old cultures die hard.
The next meeting of the Forum will be 19th June 2015