Intermittent Discharges

A Guide to Modelling Intermittent Discharges

Reference: 14/WW/17/17
ISBN: 1 84057 749 5
Published Date: 13/01/2015

This report provides an up-to-date and accessible guide to modelling intermittent discharges (i.e. combined sewer overflows, storm tanks and pumping station overflows). It is aimed primarily at water managers and asset planners in water companies who commission work from specialist modellers and authorise investment plans based on the results. It will also be useful for anyone who wants to gain an overview of current practice in the UK.

The guide describes a four stage process to modelling intermittent discharges: defining the problem, selecting an approach, applying the model, and analysing uncertainty. Each stage is broken down into a series of steps, which discuss critical decision points and summarise current good practice within the UK water industry.

A checklist at the end of each stage highlights key issues to be agreed between those responsible for building water quality models and those that use and interpret the model outputs.

Price: £23  

Risk Based Prioritisation of Pharmaceuticals

Reference: 14/WW/17/16
ISBN: 1 84057 735 5
Published Date: 06/08/2014

A range of pharmceuticals has been detected in the natural environment across the world. Concerns have therefore been raised over the potential effects of active pharmaceutical ingredients in the environment on human and environmental health and , over the past 15 years, a substantial amount of work has been undertaken to determine the occurrence, fate, effects and risks of pharmaceuticals in the environment. The aim of this project was to provide the UK water industry with a priority list of pharmaceuticals to indicate the contribution from wastewater treatment and help inform UK policy. Environmental exposure of the most used pharmaceuticals in primary and secondary care, plus some compounds considered an environmental hazard was compared to relevant environmental effects data and the compounds prioritised to identify those where attention should focus. The data was used to select pharmaceutical compounds for the second Chemical Investigations Programme and two priority lists of pharmaceuticals were generated for further consideration by the wastewater industry.

The primary priority list contained fifteen compounds that demonstrated an environmental risk during the prioritisation. The secondary list contained twenty-five compunds that demonstrated the possibility of environmental risk when associated prioritisation uncertainty was considered.

Price: £17  

Alternative Approaches to Bacterial Reduction for WwTW Discharges: Phase 2 Field Trials and UV Desk Study

Reference: 13/WW/17/15
ISBN: 1 84057 698 7
Published Date: 12/11/2013

EU Legislation has driven continuous wastewater discharge disinfection focussing on UV treatment. Reducing spills of intermittents by providing storage has been the normal approach.

This study proposes determining disinfection requirements on a site specific basis. The approach links the UV 'validated' dose to the microbial reduction achieved. The benefit of this approach is to achieve a reactor design validated against the microbial reduction required.

Benefits include: better targeted investment, supported by evidence; minimised capital and operating costs through better understanding of carbon costs associated with UV irradiation; demonstration of the methodology enabling production of site specific evidence to support a flexible, consistent approach to the disinfection of discharges; ability to meet revised bathing water directive targets and reduce the risk of EU infractions and beach closures; applicability of the protocol to intermittent discharge disinfection.

Price: £21