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Andrew Urquhart, director of development at Envar has described how waste paper sludge can be utilised beneficially in the agricultural sector to improve financial and environmental performance.

The Environmental Permitting Regulations (EPR) of England and Wales 2010 were introduced on 6 April 2010, replacing the 2007 Regulations, which combined the Pollution Prevention and Control (PPC) and Waste Management Licensing (WML) regulations.

Broadly speaking, the EPR apply to pulp and paper manufacturing activities where the plant has a production capacity of more than 20 tonnes per day.

This covers any activity associated with making paper pulp or paper, including recycling.

The paper industry is highly proficient in the recycling of its products, however, the number of times that cellulose fibres can be re-sued is finite because the fibre length decreases with each use and the fibre strength decreases.

At this point, the fibres become a waste and so the challenge is to avoid sending de-inked sludge to landfill.

The EPR states that operators should ‘consider all avenues for recovery of fibre and filler from de-inking and wastewater treatment’.

A number of options exist; for example, incineration can be employed to generate energy.

However, the EPR also allows ‘land spreading, where it represents a genuine agricultural or ecological improvement and the ultimate fate of pollutants present pose no environmental harm’.

Envar is a waste management and recycling company specialising in organic waste and market/product development.

Scientists from Adas, Envar’s parent company, were part of the team that originally developed the Safe Sludge Matrix, which stipulates the suitability of bio-solids being spread to land in relation to different crops.

The Matrix ensures food safety and gives retailers and the food industry confidence that the use of biosolids in agriculture is not only completely safe but also fully sustainable.

On the back of this concept, the recycling of other waste materials was developed.

Further activity involving the application of waste materials to land includes the spreading of flocculent sludge from water treatment to agriculture and the utilisation of digestate from anaerobic digestion for the improvement of agricultural soils.

In-house soil scientists supported by accredited laboratories are able to assess agricultural land and accurately determine whether specific waste materials will be of agricultural and/or ecological benefit.

With a history of involvement with farmers and landowners, Envar staff are able to broker reliable markets for such waste materials.

Envar works for a large number of paper mills, helping to reduce waste to landfill and ensures that these materials are utilised in a responsible and sustainable manner.

DS Smith subsidiary Severnside Recycling is working with Envar to tackle the 26,000 tonnes of waste material that is generated by St Regis Hollins Mill in Lancashire, another DS Smith subsidiary.

Operating four paper mills, the company produces around one million tonnes of 100 per cent recycled paper per year.

Envar has been working with Severnside Recycling, handling the waste from its mills for two years.

Work at the Hollins Mill began in August 2010.

Envar’s role in the partnership with Severnside has been to evaluate recycling options for the mill’s paper sludge and crumb, and to ensure that the most sustainable option is adopted.

A number of alternatives were considered, including incineration, land restoration, soil improvement and animal bedding.

Of these, the latter three were considered to offer the greatest benefits.

The paper crumb from the mill is ideal as a bedding product because it has low moisture content and no odour, offering livestock farmers a cost-effective and sustainable alternative to intensively farmed straw.

Furthermore, paper sludge contains useful plant nutrients and a high proportion of organic matter.

It is also alkaline, which is beneficial to many agricultural soils.

Paper sludge can be used in restoration projects as an ingredient in manufactured soil.

If trees are then grown on the site, these can be harvested at a later date for paper manufacture, offering a longer-term closed-loop recycling option.

Soil science plays an important role when paper sludge is utilised on agricultural land.

This is because the physical and chemical attributes of land have to be matched with the properties of the recycled material.

This is important because the Environment Agency has to be satisfied that the requirements of the EPR are being met.

In a post-recession climate, businesses need to be sustainable in every sense of the word.

Sludge recycling is therefore an attractive proposition, as long as it is managed in a responsible manner.

Envar (ADAS)

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