Balmoral clears the legal hurdles

A change in legislation has prompted Balmoral Tanks to restructure and test its range of packaged wastewater plants. Natasha Wiseman visited the firm's headquarters in Aberdeen to find out what has been achieved

Balmoral Tanks has restructured its range of package treatment plants in response to new European legislation regarding effluent discharge. The new range of small to medium-sized package treatment plants can be used in homes or developments housing up to 50 people.

With an eye on the new BS EN 12566-3 European standards, Balmoral, in conjunction with the DTi and Cranfield University’s School of Water Science, designed the new system to address optimum effluent treatment and other key aspects that are important to the supply chain including product storage, transportation, installation and maintenance.

Phase 1 of the research programme involved an independent 17-week design evaluation programme at Cranfield University, based on the procedures set out in BS EN 12566-3. This work allowed the new design to be fully verified in practice before committing the finished product to the CE accredited test house at PIA in Aachen, Germany.

For the Cranfield tests, a single household model was chosen as it is widely recognised that the most challenging situations are faced by small systems. A full-size prototype plant was fed with genuine sewage from the university sewage works including washing machine effluent and bath water.

The feed setup was designed to reflect the expected peaks and troughs typical of a single household. Extreme situations were also tested, including no feed, high loadings and power failure, typical of what the plant would face during CE mark European testing. These tests provide a much more rigorous regime with a wider spread of measurements compared with previous approaches and ensure realistic simulations of real-life scenarios.

CE accreditation

The investment in on-site testing at Cranfield was justified as the system earned full CE accreditation and its performance declaration from PIA, Aachen. It is now verified that the HydroClear reliably provides an effluent quality of 10:20:6mg/l (BOD:suspended solids:NH4-N) respectively. This equals a class-leading BOD removal of 97%.

Overcoming pitfalls

HydroClear is an aerated biological system that uses a moving-bed biological reactor (MBBR). A new process in the package wastewater market, MBBR technology embraces the benefits of common fixed-film media processes without suffering their common downfalls.

Overgrowth of bacteria leading to channelling is an issue with common market process designs such as submerged aerated filters, rotating biological contactors and trickling filter designs. The MBBR process, widely adopted in larger-scale systems, is incapable of blockage as its media is constantly mobile. The sloughing effect of the media also removes excess growth promoting a continuing regrowth of healthy bacteria, vital to maintaining reliable treatment.

The HydroCIear represents Balmoral’s third generation of sewage treatment plants. Its predecessor, the continuous aeration plant, proved popular with trade professionals and end-users alike but the company’s commitment to providing best-in-class products led to the creation of this solution.

Tim Mackley, wastewater product manager at Balmoral Tanks, said: “The design, performance and shape of the HydroClear offers substantial improvements on what Is currently available. European regulations demand higher effluent quality and effective use of new technology was required to achieve this.

“Our successful CAP product was limited to six and 12 population sizes, and we recognised that a broader product range was desirable. The new HydroClear is available in six, 12, 20, 30, 40 and 50 population models.

“We are extremely proud of this product, which is a pioneering application of the latest wastewater technology rather than a variation on what has gone before. Taking today’s challenging wastewater treatment environment into account, a broad range of requirements were addressed.

Legislative demands

“We took the design right back to first principles. A three-year programme of research, design, engineering, testing and production ultimately enabled us to produce a system that far exceeds legislative demands through its reliability of performance. The HydroClear offers a build quality the industry has come to expect from Balmoral; a rotationally moulded one-piece high-density polyethylene tank, providing robust on-site characteristics and a ruggedness not found in competitive products.”

Maintenance eased

The air-blowing compressor is housed in a cleverly designed sealed manway cover. This means there are no electrics or moving parts within the vessel. Internal servicing is accessed from ground level, which make for easy, quick and safe maintenance.

Allan Joyce, Balmoral Tanks’ managing director, said: “Although our previous range of wastewater treatment plants was doing extremely well, Balmoral recognised that, to satisfy our clients, particularly installers, modifying the existing product wasn’t really an option.

“They wanted something that was more easily installed, with a low invert depth, while end-users demand high performance, low maintenance and reliability. I’m satisfied the HydroClear exceeds all the criteria called for. We are offering a host of improvements at a highly competitive price,” Joyce said.

“Naturally, we are happy to advise specifiers, installers and end-users on the benefits of this all-new range through our RIBA-approved training modules.”

End-of-test results and industry feedback indicate that the HydroClear operates at the top end of the performance table. EC legislation now dictates that all sewage treatment plants must display effluent quality information on documentation provided with the product.

“The HydroClear is showing significant improvements and industry-leading performance in terms of effluent quality, transportation, storage, installation and maintenance,” added Joyce.

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