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Filtration+Separation September/October 2011

Wastewater treatment:

Extreme separation reduces space requirements A

new pre-treatment process with a small footprint that significantly

reduces the load of subsequent steps has been developed by

Epuramat. Bogdan Serban describes the technology, its advantages

and its applications.

The problem

The global market for wastewater treatment is estimated at $480 billion - $126 billion for municipal and $86 billion for industrial addressable markets (Water, Wastewater and Filtration: World Markets, published by the McIlvaine Company). This looks set to grow further as new legislation imposes increasingly strict regulations on municipalities and industrial companies, forcing them to rethink their wastewater treatment processes.

Canada today has some of the strictest regulations on wastewater discharge, which are enforced most stringently in its environmental protection zones. Europe is not too far behind: the European water framework directive (2000/60/EC), for instance, targets a standardisation of water policy at a high level for all EU member states until 2015.

When combining the strict global regulations on water/wastewater with the additional challenges - such as rising costs of fresh water and energy, high water disposal costs, and in many cases limited resources and understanding of wastewater and how it should be safely discharged - many municipalities and industrial companies are realising the immediate need to rethink their wastewater treatment processes.

Although huge steps have been made in the fields of secondary and tertiary treatment of wastewater within the last decade, with particularly significant developments in membranes and ultrafiltration, there has been little progress in primary treatment. As before, newly built municipal sewage plants are still typically in the form of large, open

sedimentation tanks, made out of concrete for primary settlement of solid material. Given the amount of space required to build new tanks, adjacent urban construction is often impossible, and additional land costs are therefore incurred. It is also often nearly impossible to expand plants after construction. In addition to the space issues, conventional sedimentation tanks can release strong odours, are challenging to clean and maintain, and have proved to have limited efficiency.

Therefore Epuramat felt that there was a need to develop an advanced technology for the primary

treatment of wastewater, particularly given that the better the mechanical pre-treatment process, the easier the subsequent treatment steps.

As a result, Epuramat developed its patented ExSep® (Extreme-Separator) device, a primary wastewater treatment solution that significantly reduces the load of subsequent treatment steps on a very small footprint.

The technology

The ExSep® uses gravity and fluid dynamics to separate solid organic and inorganic material

The ExSep® from Epuramat.

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Filtration+Separation September/October 2011

from liquids by using virtually no energy and no chemicals at an efficiency of up to 99.9%, with a standard degree of separation between around 200 to 25 microns. ExSep® is a scalable system and can handle capacities of 0.5 to 500 m3/h.

Wastewater passes through a flow tube, which has a bluff body at the end where the inflowing water is deflected and slowed down. At this stage, several hydraulic processes interact, causing the solids to sink to the cone-shaped bottom of the ExSep®, where the suspension thickens and is sucked off by a pump for subsequent sludge treatment.

The performance of the ExSep® is monitored and controlled by a programmable logic control which can also be controlled remotely. All the changeable factors for treating the wastewater are programmed in an initial calibration and control session. The bluff body is adjustable, meaning the settings can be adapted onsite or remotely to meet the characteristics of the wastewater. This ability to alter the settings means the ExSep® can be used for municipal wastewater treatment plants with varying diurnal cycle lines as well as for wastewater from a variety of industrial processes, where solid material needs to be separated from a liquid medium.

While the ExSep® is a module mainly used for primary treatment of wastewater, Epuramat also developed a complete, turnkey solution for wastewater treatment, marketed as Box4Water. Box4Water is a compact and mobile solution for decentralised wastewater treatment within one standard container. The system is beneficial for remote communities without their own access to a centralised wastewater treatment plant. Along with the ExSep® primary treatment process, the container also uses a membrane bioreactor (MBR) with ultrafiltration. An ozonation device can be added for additional safety.

Box4Water also contains a buffer tank which equalises the influent and can hold a daily peak flow. A complete sludge dewatering devise is also installed within the container. It produces sludge with a dry solids (DS) content of up to 17% without the addition of flocculants (up to 25% DS with the addition of flocculants). The effluent resulting from the Box4Water is in compliance with European and international regulations for direct discharge into open water. It is available in standard sizes to treat 12.5, 25, 50 or 60m3 of wastewater a day or bespoke solutions can also be built to meet specific customer needs.

Operation

Using the ExSep® technology, Epuramat is able to build compact, energy efficient plants – ideally suited for a large number of industrial and municipal applications.

Epuramat believes that there are few alternative solutions available in the marketplace as compact and as energy efficient as the Box4Water in areas below 2.000 population equivalent (PE). This means that both small and remote communities will benefit from the advantages of the Box4Water. Its modular configuration means that the Box4Water can be built and delivered at very short notice (on average three months). The plant then can be commissioned within three working days.

Municipal use

As some of our wastewater treatment plants are reaching full capacity due to growing populations and the construction of new modern local amenities, the ExSep® was designed to help unload existing plants. For example, in Luxembourg in the 1980s a wastewater treatment plant was designed for 1.000 PE to treat wastewater from the second largest fuel and service station in Europe. Following a number of extensions, including new restaurants and toilet facilities, the gas station was soon running at 3.000 PE. The cadastral limitations onsite meant that building a new plant or extending the plant by additional sedimentation tanks was not possible. As a solution, Epuramat installed two ExSep® 500s in a small space, immediately increasing the capacity of the wastewater treatment plant, and ensuring that the effluent was then compliant with the environmental regulations for direct discharge into open water.

Water reuse plant with ExSep separators.

Box4Water is a mobile wastewater treatment system.

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A more conventional solution would have entailed either building a new plant or extending the existing plant. For 3.000 PE, when including the cost of acquiring additional land, this would have amounted to an estimated investment cost of up to €1 million. Moreover, given that the plant would have been three times larger, the operational costs would also have been likely to rise accordingly. Furthermore, this does not consider the additional planning, realisation and commissioning times of three to five years, and the lengthy process of obtaining building permission for the plant and the pipes.

By using the ExSep® solution, the investment costs for extending the plants were minimal; the only additional operational costs were for the additional consumption of energy of around 3kWh for the pumps and control unit. The time

from order of system until commissioning was only three months and no building permission was necessary.

Industrial use

The ExSep® also has a big part to play in industry through for instance the re-use of industrial process water, mining and drilling related wastewater treatment and – in combination with a specially developed cross-flow membrane – the separation of oil from water in the course of oil production, oil spillages and remediation work.

For example, the ExSep® has been used by a German plastics recycling company that needed a solution to help it reduce its heavy monthly expenditure, of several thousand Euros, spent

on fresh water during the production process. In the past, all resulting wastewater from the production process had either been discharged or rudimentarily treated by exterior settlement tanks. By installing Epuramat’s ExSep® at the recycling company’s site, solid particles could be separated from the water, and the latter, after further treatment onsite, could be re-used again in the production process. This has reduced the company’s fresh water expenses by almost 80%, and has saved the firm over 40% per month, when also taking into consideration the investment costs and monthly operational costs for the Epuramat solution. The ExSep® system was delivered within months, and no external approval was needed for its construction.

The marketplace

As the issue of water scarcity becomes ever more serious, rising further up governments’ agendas, policymakers are continuing to try to develop new regulations forcing countries to both save water and treat wastewater for re-use. Epuramat is particularly focusing on developed countries where it already has a strong presence – including the US, Canada, Germany, France, Luxembourg, the UK – and where there are stringent environmental regulations. Its new distribution agreement in Canada is helping to raise awareness of the ExSep® and the Box4Water in the country, and its development of compact, high performance wastewater treatment systems.

So far, Epuramat has seen particular traction in providing wastewater treatment solutions for small remote communities, as well as overload relief for existing wastewater plants and re-use of industrial process water. Epuramat is also seeing opportunities in the fields of mining and drilling related wastewater treatment, and dewatering of digestate and treatment of the resulting water in the course of biogas production. In addition, oil-water separation shows perhaps the biggest margin for growth. It is relevant for both land and maritime applications, and could be beneficial in oil leakage situations.

Epuramat is also considering ways it can work with UNDP, UNOPS and NATO to create a compliant water and treatment solution for small- and medium-sized wastewater applications. Future developments may also include ways of providing water solutions in undeveloped countries; for example in areas of extreme poverty such as in the Horn of Africa, or in war stricken zones. As the population continues to grow, the importance of treating wastewater for municipal and industrial purposes, in order to preserve fresh water supplies and reduce water shortages should not be underestimated. •Contact:Birgit Manzoni

Business Development

Tel: +352 35 70 72 40

E-mail: birgit.manzoni@epuramat.comThe interior of the Box4Water unit.

Box4Water can benefit small and remote communities.