Waste money

The days where water or process waste is jettisoned into a nearby river or landfill are rapidly being relegated to history.

In their place is a new generation of technologies that allow both solid and liquid waste to be converted into energy or other useful by-products.

Where possible, we look to recycle and re-use the water and/or produce biogas or other beneficial materials from the waste stream

Veolia Water Technologies’ Ian Hart

While the relentless drive for efficiency is partly behind the trend to reuse, tougher environmental regulations mean that many of the traditional methods for disposing of waste are no longer viable.

Research from Frost & Sullivan finds that smart industrial waste management is becoming a defining factor in modern economies.

This will increase as primary materials become expensive, transportation costs increase, and waste handling and disposal costs escalate, it says.

“Preference for advanced waste treatment such as smart collection and sorting, recycling and incineration with energy recovery adds to market growth,” says Frost & Sullivan energy & environmental research analyst, Monika Chrusciak.

The researcher calculates that the global market earned revenues of $387 billion (£259bn) in 2013, and will almost double that by 2020.

Veolia Water Technologies business development director Ian Hart says many process industry customers are looking to treat their waste stream for reuse to minimise mains water usage or effluent discharge.

“Where possible, we look to recycle and re-use the water and/or produce biogas or other beneficial materials from the waste stream,” says Hart.

He says this closed-loop thinking means that waste is converted into energy or re-used for other applications.

“For example, we have been working with Diageo to recover energy via anaerobic digestion using by-products of whisky production as the fuel source,” he says.

The biomass can be used as a fuel, while anaerobic digestion is used to produce biogas from the liquid.

These are then recycled back into the distillery. Hart says that financial incentives mean the commercial viability of anaerobic digestion (AD) treatment is becoming much more attractive.

“We are taking the lead on these type of processes but also combining them with other Veolia technology to recover water as well.”

Veolia’s water treatment system has helped to put the Annandale Distillery back on the single malt map.

The distillery closed in 1919 but after a three-year refurbishment, its first cask was filled in November 2014.

It had the choice of using mains water or its own on-site borehole, and Veolia’s engineers showed how the borehole water could be treated economically, avoiding the cost of installing a mains supply and ensuring a consistent source quality.

When it comes to discharging effluent, most large-scale industrial applications must pay for wastewater treated by their local water authority.

The charge levied by the water companies is calculated using the Mogden Formula, which assesses the costs of transporting effluent from an industrial site to the local treatment works to be treated before being released back into the natural water course.

However, Xylem Water Solutions general manager of specialty solutions Paul Winnett says a culture of treatment before discharge could save the food processing industry hundreds of thousands of pounds every year.

“There are various methods available to reduce a site’s Mogden charges, including membrane filtration systems, aeration systems and the use of a wastewater recovery and re-use system,” he says.

The Enhanced Capital Allowance (ECA) scheme for water efficient technologies encourages companies to invest in sustainable water products and systems.

An example of the sort of savings that can be achieved by industry involved a food processing plant in the Midlands which had a Mogden Charge of more than £162,000, says Winnett.

“Our analysis demonstrated that there was an opportunity to make a significant saving on annual effluent discharge bills and potable water consumption,” he says.

The effluent volume remained the same at 40,000 litres, but by reducing its chemical oxygen demand (COD) at an overall cost of £42,500, the food processing plant realised a huge saving of £119,500.

The food and beverage sectors have really picked up on waste management opportunities in the last six to eight years, says Andy Brown, technical director at Ondeo Industrial Solutions.

In particular, the rising cost of energy has driven the adoption of AD technologies.

However, the effluent that comes out of the AD process, isn’t fit for disposal to the environment, says Brown , and requires further treatment and then filtering.

Ondeo Industrial Solutions offers water and wastewater services to an array of industries, and it also has a water sciences laboratory where it conducts quality testing for wastewater to fully accredited standards.

Brown sees increasing demand for the compact treatment of different waste streams for heavy industry looking to dispose of ‘recalcitrant’ compounds that can be quite toxic.

An example includes the fossil fuel power plants that have installed wet scrubbers to remove sulfur dioxide from emissions in response to tightening environmental regulations.

“Scrubbers have a waste stream that contains heavy metals,” says Brown.

“We have developed technology that can allow them to remove those heavy metals and other contaminants.”

This process uses a combination of membrane filtration, chemical conditioning and ion exchange, and then the waste stream is converted to a small amount of solid waste that can be incinerated.

Brown says other technologies worth watching over the next few years include advances in reverse osmosis technology and zero liquid discharge, which allow operators to recycle and reuse all of their water with the help of evaporation technologies.

“Technologies are also getting more compact and simple,” he says.

“An example is a low-energy membrane bioreactor which may in the future be able to treat wastewater to a very high standard without the need for excessive energy.”

A good example of the food industry’s embracing of AD is Tamar Energy’s joint venture with QV Foods, which takes vegetable trimmings from its production line, as well as from the retail sector, local commercial sources and households.

“Their site is fairly remote so it was not economically viable to transport these trimmings excessive miles for animal feed,” says Tamar Energy engineering manager Sacha Grodzinski.

“The electricity generated provides QV Foods’ power requirements, and the ‘constant baseload’ nature of AD is an ideal match for the 24/7 electricity demands of the site.

“Even in the most efficient food supply chain, there is unavoidable waste. AD offers an opportunity to use this resource, which otherwise may be either sent for composting or to landfill, as a means of creating energy.”