Landfill Leachate Methane Stripping Plants (MSP)

Challenge

The disposal of excess landfill leachate is one of the most significant costs for a landfill operator throughout the landfill’s life. Low-cost disposal routes for landfill leachate are therefore highly prized. One of the most cost effective of which is disposal to the public sewer.

However, when leachate is being pumped directly from landfilled waste that has a putrescible content, it can contain relatively high concentrations of dissolved methane gas. Methane is more soluble in water than oxygen, at 20oC 25mg/l of methane can dissolve into leachate, but more typically figures of 0.5mg/l to 15mg/l are present. To enable the on-going use of such cost-effective disposal outlets for leachate, operators are prepared to install treatment systems that limit the concentration of dissolved methane to below acceptable levels.

Our clients needed assistance from a consultant that they could trust to procure suitable treatment plants to reliably and cost effectively treat their landfill leachate to a quality that allowed its acceptance into the sewer by the sewerage operator. Whilst specialist contractors can supply methane stripping plants, our clients value SLRs input as not only are we able to provide useful guidance on the type of equipment to install but can also complete the work required to obtain Permits and Permissions along with associate issues such as ecological, noise and odour surveys and ‘best available technology’ assessments. In addition, SLRs specialist teams can also provide or critically review designs relating to secondary containment, civil and structural engineering and process designs and can also negotiate on behalf of our clients with the trade effluent providers.

Solution

SLR were selected as our ‘One Team’ culture enables us to deliver a seamless project from inception through to final operation. Typically, SLR is involved with initial optioneering works, design, production of tender packs and management of tendering, selection of a suitable contractor, design reviews (such as HAZOP studies), design iterations and delivery of the MSP construction project.

During construction SLR often undertakes roles of Principal Designer (under CDM) and Owners Engineers representative and can also provide CQA engineer roles throughout the build.

SLR has supported clients on numerous methane stripping plant projects, ranging from tendering and installation management of smaller, ‘packaged’ MSP plants on a series of sites to bespoke, one-off plant designs for single, larger MSPs on individual sites.

Project designs have variously incorporated arrangements for blending of other effluents, control of the formation of scales and sludges, control of foaming, management of power consumption and provision of secondary containment designs to best practice standards.

Impact

SLR have delivered successful methane stripping plants on behalf of our clients as both individual projects and as a linked delivery of interchangeable plants to a series of sites, providing cost effective solutions for a client whilst maintaining the cooperation of the sewerage undertaker while installation works were on-going.

Installations have ranged in size from 75m3/day capacity plants to plants that can discharge more than 200m3/day. We have helped develop overall plant designs that are entirely new build, incorporating cast-in-situ reinforced containment bunds, new sewer connections and power supplies to plants that reuse and re-purpose existing redundant infrastructure or to ‘packaged’ plants that can be installed to sites relatively rapidly with the minimum of investment required for enabling infrastructure.