Practical Application of Modular Off-site Build: A Commissioning Perspective
Baird, A. Technical Director, WPL
(free)
Abstract:
A range of biological wastewater treatment technologies is available from manufacturers in the UK including variations on the submerged aerated filter (SAF).
One of those companies is WPL which has supported postgraduate university research at Cranfield University on the internal hydrodynamics of reverse cyclic SAF reactors. The research was applied in a pilot engineering design project investigating how the rate of removal of organic contaminants can be improved by reducing the ratio of media to wastewater inside the tank. The focus of the research and development work has been to develop a WPL Hybrid-SAF™, which incorporates offsite build and modularisation to aid the efficiency of installation and commissioning as well as enhanced process and energy efficiency.
The hybrid model, which has a patent pending, has been applied in nearly 10 UK water utility and large commercial projects for carbonaceous and tertiary nitrification. Substantial efficiency gains have been achieved in terms of process and energy consumption as well as installation. In one application a 2,000 population equivalent (PE) plant was installed in a single morning, with commissioning commencing immediately. Furthermore, 3D computational fluid design (CFD) modelling of the treatment process for an individual site makes it possible to offer an accurate estimation of project resource requirements, including process requirement, workforce skills, costings, construction and commissioning.
Introduction:
Water scarcity and need to reuse water are increasing the demand for packaged wastewater treatment
plants globally. In addition, regulation is tightening as governments face growing environmental
concerns about wastewater disposal. Market analyst Technavio has projected growth in the global
packaged wastewater treatment market at a compound annual rate of about 9% from 2015-19.
The legacy of the higher operational cost of packaged treatment plants over traditional activated sludge
and trickling filter plants has historically posed a challenge to the growth of the market, but new
technological approaches have made significant efficiency gains in recent years. When whole life
equipment costs are considered, there are multiple areas in the delivery of these systems that can be
honed. Firstly, they require electricity – for air blowers, water pumps and drives – so improved efficiency
throughout the process train can reduce energy footprint and cost. The configuration of the treatment
process and hydraulics, including the media, have historically been underexplored and are ripe for
optmisation. Finally, the industry is learning quickly that offsite construction, faster installation and easier
maintenance also provide significant scope for enhanced competitiveness.
The two main segments in the packaged wastewater treatment market are municipal and industrial.
Technavio’s analysis shows the global municipal segment is expected to grow steadily from 2015-19,
reaching a revenue of around US$13 billion by the end of 2019. Uptake of packaged treatment plants
by UK utilities is increasing as they seek to meet tightening Environmental discharge consents on
constrained sites.
