Project Appreciation and Objectives
Improved primary treatment through 'smart' control of desludging at WwTW offers the potential for lower operating costs for subsequent wastewater and sludge treatment. The majority of WwTWs have pumps controlled on manually set timers resulting in poorly optimised and inefficient desludging systems. Poor control of sludge blanket level leads to sludge build up, solids degradation, extra organic load on secondary treatment and dilute sludge, increasing the operating costs of wastewater treatment and sludge handling/treatment.
Current approaches based on sludge blanket monitoring, sludge density and pump torque can all perform well under certain circumstances but no single monitoring and control solution currently meets the industry's needs. The objective of this project is to develop a 'smart' control approach that can be adapted to existing sludge withdrawal systems.
The project will draw on current experience to develop an approach that offers simplicity and high reliability, low capital and maintenance costs, can achieve higher or more consistent sludge solids concentration and is compatible with subsequent processes.
Business Benefits to Clients
The project outputs will enable improved performance of existing desludging operations at WwTW. Specific benefits are:
- Reduced OPEX of wastewater treatment.
- A cost effective monitoring and control solution.
- Increased sludge treatment capacity.
- Collate operating experience of current control systems.
- Compile up-to-date information and costs on auto-desludging technologies.
- Assess and define the requirements for smart auto-desludging control.
- Undertake an economic assessment and identify potential cost savings.
- Design and produce a standard specification for a smart auto-desludging scheme.
Phase 2 (separately funded) - Implementation of the approach at pilot sites with support from WRc.
Project Output and ImplementationM
- Compilation of up-to-date data for existing auto-desludging solutions , including overall cost/benefit of smart desludging, to guide selection of best value solution on a site specific basis.
- Standard specification of a smart auto-desludging system - for asset standards to deliver capital cost efficiencies for new wastewater treatment works and capital maintenance of existing wastewater treatment works.
Phase 2 (separately funded) will deliver a tested 'smart' approach, implemented with the support of WRc.
Related WRc Work
- Extensive audits of WwTW in the UK over the past 10 years, including assessing auto-desludging systems and understanding the risk to operations.
- Various projects developing industry standards which aim to simplify and align water companies to reduce cost. For example CP455 Standardising Control Panels for New and Transferred Small Pumping Stations (2011).
- Instrument User Group (2008 to 2012).