Shining a light on sludge


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HACH LANGE's Solitax turbidity/ suspended solids sensor has been integrated into a tanker reception system to enable the measurement of solids concentration in wastewater movements to and from treatment plants and in trade waste applications for monitoring strengths of imported wastes.

JR Pridham Services Ltd (JRP) developed the system to provide visibility of both quantitative and qualitative data, and the systems have been widely adopted by the UK Water industry because they provide a number of valuable advantages:

  1. Accurate revenue collection from imported wastes
  2. Inefficient sludge movements can be highlighted
  3. Inefficient treatment plants are identified
  4. Vehicle movements can be optimised
  5. Charges can be validated
  6. Cost savings are identified
  7. Efficiency improvements are made possible
  8. Enhanced visualisation, audit trail and regulatory data capture

JRP's volumetric tanker reception solutions are delivered under the brand name ‘WaSP’ and applications include Domestic Waste Imports, Sludge Interworks, Trade Waste Imports, Septic and Leachate Discharge, weighbridge applications and Vehicle Mounted transaction monitoring (‘WaSP Vm’).

At those plants for which on-site sludge treatment or disposal is not available, the transportation of liquid sludge is conducted via dedicated road tanker. The management and running costs of operating either an internal or contracted fleet to conduct inter-works sludge movement is a costly exercise, particularly in the light of recent fuel cost rises. Therefore it is vitally important that the system is managed as efficiently as possible.

Once a WaSP system is installed, it can be configured to meet individual customer needs with specific logging-on or verification procedures. For example, some customers employ GPS vehicle tracking integrated into the system to capture complete vehicle movements, however, the basic operational procedure is as follows:

  1. Tanker arrival 
  2. Tanker hose connection
  3. Key fob authorisation to recognise driver
  4. Driver answers optional questions such as:
    a. Where have you come from?
    b. What is your destination?
    c. What is the waste class?
    d. Do you have a Manifest ticket number?
  5. Summary display – agreed or edited
  6. Transaction authorised and actuator valve opened
  7. Cumulative flow data displayed continuously with strength averaging
  8. Data stored in WaSP and sent by GPRS to host web server
  9. Data available for reporting, billing and analysis etc.

Many wastewater companies have adopted transport scheduling packages and workload forecasting systems to manage fleet operations and shift patterns, etc. These systems assist in generating efficient workflow patterns and resource management. With the help of additional monitoring technology and refined reporting techniques, the UK Water Industry has been able to analyse sludge movements in far greater detail providing further opportunity for efficiency improvements and cost reduction in the transportation of liquid sludges.

By  monitoring, reporting and analysing each movement transaction the wastewater operations team can build a concise overview of its operational performance, providing details of inefficient treatment sites, identifying areas where further investment in treatment or disposal may be required and gaining an understanding of the costs attributed to current practices.

Commenting on his company's partnership with HACH LANGE, JRP's Business Development Director, Ian Procko says, 'It is appropriate that the Solitax is an optical sensor that measures solids by shining a light upon particles because, in a way, that is exactly what the whole system does – we provide the client with visibility of the volumes and strengths of sludges being hauled between works and commercial liquid wastes being imported for treatment. With the further benefit of enhanced web based visualisation packages and customised reporting we can ensure that regulatory reporting and commercial billing can also be achieved at the touch of a button.'

'The Solitax is a fundamentally important part of the system. It is probably the most widely accepted online suspended solids sensor in the market, so our customers can be confident that we will deliver a tried and trusted technology.
Our work has demonstrated that the Solitax is able to provide long-term consistently reliable and accurate data even in highly aggressive conditions, which is why it is ideal for our applications.

Each sensor is fitted with a tiny wiper that operates before and after each transaction to ensure that results are accurate and repeatable.

Our product range has been greatly enhanced by our relationship with HACH LANGE and their close involvement in product development has been highly valuable.'

'In terms of further product development we are also utilising the Solitax instrument together with the HACH LANGE SC100 controllers in various process optimisation solutions (‘WaSP POS’) in which we monitor and report process parameters such as flows, solids quality (via the Solitax) and temperatures for various processes throughout the treatment cycle; digestion, blending, thickening, etc.'

'Data generated by the WaSP POS systems are transmitted to a web-based dedicated portal where drill-down reporting is available for analysis and review, providing an overview of the measured parameters between different processes and highlighting process alerts or conditions. This enables managers and operators to ensure maximum efficiency in sludge production and treatment.'

WaSP Case Study

The implementation of an interworks sludge logging scheme, involving 23 single and multiple line WaSP systems, generated cost savings of approximately £500,000 in the first year of operation.

The data provided by the monitoring systems clearly identified poorly performing sites where inappropriate strength sludges were being removed by road tanker. Excessively thickened product can cause increased loading and unloading times, whilst the transportation of weak sludge concentrations, with very large water contents, is extremely inefficient and costly.

The cost savings were achieved through reduced transportation costs and improved process optimisation.

Looking forward, UK Water Companies are forecasting a continued rise in sludge production and this will intensify the need to manage sludge as effectively as possible. Clearly, tanker receptions systems have a vital role to play in achieving this objective.

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