Sustainable water and wastewater processing

Lead: Judy Lee

Among different industries, current industrialised livestock agriculture has one of the highest consumptions of water and produces up to ten times more polluted wastewaters in comparison to domestic sewage.

At Surrey we have assessed the use of single and combined advanced oxidation processes (AOP) such as ozone, ultrasound, UV and hydrogen peroxide for the treatment of real slaughterhouse wastewaters and found individual application of AOPs did not show high efficiency in organic matter removal, while the combination of different AOPs reached direct discharge limits set by the European Union and showed potential to be used for water treatment intended for agricultural irrigation.

Lead: Rex Thorpe

In collaboration with Thames Water, and Surrey department's; Department of Civil and Environmental Engineering and Centre for Environment and Sustainability, we have explored the optimisation of the digestion of sewage sludge to make bio-gas from which renewable electricity is usually generated.

Lead: Madeleine Bussemaker

Ultrasonic effects have potential applications in the processing of lignocellulose at various stages along the conversion process.

We are interested in ultrasonic pre-treatment of lignocellulose, as well as the ultrasonic enhancement of the conversion of fractionation products. Pre-treatment of lignocellulose occurs in a heterogeneous solution where the collapse of cavitation bubbles can enhance the accessibility of biomass components from pits and cracking observed on the surface of the biomass. In addition, the chemical effects of ultrasound have applications for enhanced purification of the polymeric component of the lignocellulosic biomass.

Lead: Judy Lee

Various liquid streams in the food and beverage industry often require the removal of water as a preliminary step prior to storage, transport or the ultimate production of powders.

Forward osmosis is a potential method for concentrating such liquids, owing to its reported lower fouling tendency compared to reverse osmosis and the lower primary energy requirements compared to thermal methods, which has shown promising results. However, existing literature on the concentration of liquid food streams using forward osmosis has primarily focused on bench scale studies, with limited reports on pilot scale studies.

Our research addresses several key research gaps in the fundamental aspects of forward osmosis in the concentration of liquid foods such as dairy whey and orange juice:

1. The extent and severity of concentration polarisation and its effect to reduce the flux
2. The conditions when fouling occurs in these systems and impact of reverse solute flux
3. Whether forward osmosis provides a lower fouling environment for this concentration process.

Lead: Madeleine Bussemaker

We use ultrasound to enhance the extraction of natural products from plants and food waste/by-products. Ultrasound is well known to enhance extractions in pharmaceutical and cosmetic industries and can reduce the time taken and chemical loading required, hence why it can be used to promote green chemistry.

We also research into dye uptake using ultrasound and have shown that ultrasound can enhance dyeing of goat hair, with shorter dyeing times and better hair colouration.

Leads: Judy Lee and Rex Thorpe

In collaboration with Antaco we have been researching nutrient recovery from and chemical oxygen demand reduction in the process water that is a by-product of hydrothermal carbonisation (HTC). HTC can produce a power-station ready renewable solid fuel (‘bio-coal’) from wet bio-wastes including sewage sludge.

Leads: Siddharth Gadkari and Michael Short

A significant amount of energy and billions of pounds are spent every year in the UK to treat industrial/domestic/municipal wastewater. However, this wastewater which typically contains a lot of organic compounds can actually be used as a valuable resource in devices known as bioelectrochemical systems (BESs).

BES are like any other electrochemical cell (e.g. battery) and consist of an anode, cathode and a separating membrane (optional), but the difference lies in how the electrochemical reaction is catalysed. In BES, at least one or both of the electrode reactions are catalysed with the help of microorganisms. By combining living biological systems with electrochemistry, BES makes it possible to utilize the chemical energy from wastewater and generate electricity (microbial fuel cells, MFCs), hydrogen (microbial electrolysis cells, MECs) or value-added chemicals (microbial electrosynthesis, MES).

Our research is focused on optimisation of various BESs through mathematical modelling and experimentation. In order to incorporate new potential treatment technologies via retrofitting or for conceptual design of new systems, our group employs mathematical optimisation models and surrogate modelling techniques to solve large-scale systems with competing objectives to design provably optimal wastewater treatment systems that incorporate multi-scale models.

Leads: Judy Lee and Melis Duyar

The detection of nano/microplastics throughout water treatment plants constitute a potential threat on the performance of water purification technologies, particularly its impact on the membrane processes remains unclear.

Here at Surrey we investigate for the first time the fragmentation of microplastics into nanoplastics, the fouling of ultrafiltration membrane by these nano/microplastic fragments and fibres, as well as their impact in membrane bioreactor systems. Mitigation solutions based on membrane surface chemistry, periodic cleaning strategies and chemical precipitation are also investigated.

Lead: Madeleine Bussemaker

Per- and polyfluoroalkyl substances (PFASs) comprise ultra-persistent, highly mobile and bioaccumulative pollutants that contaminate water sources. These chemicals are highly stable and very difficult to destroy. They can accumulate in solids, people and crops, leading to health problems.

In collaboration with Arcadis we are investigating using cavitation generated by ultrasonic waves to mineralise PFAS pollutants.

Lead: Judy Lee

The increase in the release of pharmaceutics into the environment has a direct correlation with the rising development in antibiotic resistant. Hospitals are considered hotspots for such a release and development, but conventional wastewater treatment plants are inadequate and inefficient at removing these.

Funded by the Royal Society Grant (ICA\R1\191053) and in collaboration with Professor Ricardo A. Torres Palma from University Antioquia, the project aims to develop, commission, and critically assess the combined biological-filtration and sonolysis processing system for the effective remediation of emerging contaminants in real hospital wastewater, and potential recovery of clean water for reuse.

Lead: Bahman Amini Horri

The variable nature of renewable energy, such as wave energy, wind energy, and ocean thermal energy, particularly when it is deployed in a large-scale capacity, necessitates the use of proper energy storage facilities to ensure the security and reliability of the energy output.

As an emission-free energy carrier, hydrogen has a great potential to be integrated with renewable energy sources. However, now, the cost of green hydrogen produced by conventional water-splitting techniques is noticeably higher than that produced from fossil fuels.

The innovative aspect of the hydrogen production technique patented at the University of Surrey offers an immediate response to the current needs in the market for efficient power generation and a significant push toward the net-zero emission regulations. Producing green hydrogen as a flexible source of storage for renewable electricity offers an excellent grid balancing service. It can also create a new downstream market for renewable power, which is fully aligned with the environmental decarbonisation policies.

Lead: Dimitrios Tsaoulidis

Gulf Cooperation Council countries are the most water stressed countries on the planet, and the renewable water resources are expected to fall below 500m³ per person per year by 2030. Relying primarily on conventional groundwater sources will not be sustainable in the long term. Furthermore, the decreasing quality of existing groundwater supplies means that arable land has effectively become ‘salted’ rendering it unusable.

Existing technological approaches for the removal of salt and other contaminants from water and soil are expensive, limited in their efficiency, non-selective, and could lead to serious health effects. The work in our Department focuses on the design of a novel low-cost energy capture and storage system, which offers a sustainable solution for improved water desalination and purification processes by using desert sand and solar ponds to capture solar radiation to drive the process.

Leads: Madeleine Bussemaker and Michael Short

Modern systems of water and energy are intrinsically linked in the water-energy nexus. To understand these highly interacting subsystems and to create more circular waste-driven supply chains, our group develops novel algorithms and mathematical optimisation models for technoeconomic assessment, and design of new processes for integrating circular economy principles throughout these systems.

Leads: Siddharth Gadkari and Michael Short

Access to clean water is imperative for the sustainable development of communities. With growing world population and rising environmental pollution, it is essential to develop faster and accurate means of determining and monitoring the water quality. The conventional methods for water quality assessment are time consuming, cumbersome, and expensive, and therefore new methods that can provide faster real-time assessment are being developed.

Microbial fuel cells (MFCs) represent an innovative technology, in which microorganisms oxidise the biodegradable organic matter in wastewater to produce an electric current. The output from MFC can also be interpreted to get a measure of the biochemical oxygen demand (BOD) in the feed water. As BOD is one of the key parameters for assessing water quality, MFC’s can work as biosensors for BOD measurement, with the added advantage of being self-sustainable.

Our research focusses on development of cost effective and operationally stable MFC based biosensors. Along with novel sensors, researchers in our group combine data obtained from these sensors along with novel algorithms to predict and control water quality on wastewater treatment plants through model predictive control.

Lead: Rex Thorpe

This work was based around the full-scale performance trials of a new bio-trickling-filter for odour reduction at a Thames Water site. The biofilm that destroys the odour molecules was successfully modelled using a combination of classical bio-chemical engineering kinetics and classical mass transfer.

Lead: Bahman Amini Horri

This was an ongoing joint-research project with NVH Global Ltd and support in-kind from Drax Power station to analyse the electrochemical performance of microbial fuel cell using advanced electrode materials for waste-water treatment, and also production of added-value chemicals such as acetic acid with CO₂ sequestration in the MES systems.