Intelligence Gathering

A Rainfall-Independent Approach to Calculating Treatment Flows at WwTW

Reference: 12/WW/23/9
ISBN: 1 84057 638 3
Published Date: 01/08/2012

Most wastewater treatment works discharge consents contain a Flow To Full Treatment (FTFT) condition that states that all flows up to a given flow rate must receive full treatment. The FTFT has been set historically on the basis of a calcuation from flow components, but recent advances in data collection provide an opportunity for an appropriate setting to be estimated from flow data.
This project has developed such an approach that can be applied in the absence of rainfall data. The development of the new approach is described and its performance and limitations are assessed.
An approach for making allowance for future growth is described, based on maximum likelihood estimation as used in the regulatory water balance.
An approach for estimating infiltration flows is described, based on the hydrological technique of baseflow separation.

Price: £21  

A Review of the Effectiveness of Mogden Formula Charging when Meeting Modern Sewage Treatment Works Consents

Reference: 12/WW/23/8
ISBN: 1 84057 628 6
Published Date: 26/04/2012

The project investigated potential disparities between the current trade effluent charging mechanism (the Mogden formula) and the costs associated with trade effluent management and treatment. The study demonstrated that the Mogden formula continues to serve the purpose of equitably charging for the reception and treatment of trade effluents. Strong evidence supports the view that the approach to charging for ammonia should be reviewed by the Water and Sewerage Companies to ensure investment cost recovery in the future. There is also a potential future need to charge for the acceptance of trade effluent containing zinc.
Other issues addressed in this study include the accurate apportionment of charges where multiple substances are removed, sludge treatment cost recovery, the management of carbon footprint related costs and options for the risk management of accepting non-biodegradable Chemical Oxygen Demand from traders.

Price: £13  

Wet Weather Definition and Impact on Planning and Regulatory Reporting

Reference: 11/WW/23/7
ISBN: 1 84057 614 6
Published Date: 19/12/2011

This report identifies and reviews the wet weather spill monitoring and recording methods employed by the UK water and sewerage companies. Analysis was undertaken of spill, rainfall, and treatment works flow data along with completed questionnaires on the water companies' practices.
There are various protocols used for counting spills, which can result in significantly different totals. The report identifies issues that affect the usefulness of data for regulatory reporting and the need for improved access to rainfall data. It explores methods to determine the significance of spills recommending that a standard method should be agreed, and indicates that a common standard is required for spill event recording and for counting spills.

Price: £19