Tackling pesticide pollution with on-farm collaboration

It’s fair to say that no responsible farmer or growers wants to pollute the environment, water courses or groundwater with pesticides. However, experiences at a Water Treatment Works (WTW) near Scunthorpe in North Lincolnshire in 2012 show how easily such a situation can occur, while the action taken by Anglian Water to allow the WTW to reopen showcases how stakeholders from across the environmental, farming and water sectors can work together to prevent issues at source.

In November 2012, routine sampling by Anglian Water of two boreholes at Winterton WTW near Scunthorpe detected traces of metaldehyde and clopyralid, both of which are extremely difficult to remove via traditional water treatment methods, and so the decision was taken to take the Winterton WTW out of operation. The boreholes were immediately taken out of use and an interim solution to source drinking water from an alternative supply was put into place.

Drinking Water standards are extremely tight, stating that no individual pesticide will exceed 0.1µg/l (0.1ppb). According to Anglian Water, this compares to a single stem of hay in 111,000 bales, or 1 grain of wheat in 390 tonnes! In fact, the water sector believes that up to 70 per cent of pesticides found in rivers can be attributed to pesticide handling areas in farm yards, and investigations into the pollution at Winterton suggest that the source was most likely to have been a single capful of clopyralid spilt in a farm yard which then found its way into the underlying water aquifer.

Faced with increasing population and housing pressures in the area over coming years, Anglian Water was keen to recommission the Winterton WTW, but the costs of removing pesticides from the water supply would be prohibitive, and it was felt a more sustainable solution could be found.

Consequently, the company adopted an innovative catchment management approach, working with seven local farmers to improve the pesticide handling facilities within their farm yards. The work focused on ensuring spills and drips are contained to manage pollution risk at source and preventing it from entering the water in the first place. However, it has also allowed Anglian Water to improve the treatment at Winterton, reducing the processes carried out and preventing the need for potentially harmful chemicals such as lime.

The refurbished plant was officially re-opened by Anglia Water’s CEO Peter Simpson at the end of April, where some of those involved in the catchment project explained the benefits. Winterton is fed by four on-site boreholes and two others to the north and the water is generally good quality, but it is very hard and contains a lot of iron.

“The timescales were quite tight,” commented Steve Palmer, Integrated Project Manager at Anglian Water. “We had a Drinking Water Regulation obligation to meet and early on we sat down and realised there were so many stake-holders in this scheme and that the relationship between those stakeholders and the project team was key to successful delivery. The team came up with some really good solutions to reduce chemical usage and operational costs on the site.”

From an aeration column, which helps to oxidise some of the iron, the water is pumped into two huge concrete tanks which were previously where the lime and coagulant to remove the iron was added, but in the new scheme they simply allow many impurities to drop out of the water, before it passes into four filters to remove debris.

The works now use a different medium in these filters which acts as a catalyst and captures any iron that’s been oxidised. Chlorine gas and phosphoric acid are used to disinfect the water and reduce the risk of lead poisoning, and under an agreement with the local health authority fluoride is added before the water is pumped into the network.

These savings have been made possible due to work on local farms as Kelly Hewson-Fisher, part of the agricultural team at Anglian Water in Lincolnshire, explained: “The main aim of catchment management is to provide high quality and high quantity water and food in an environmentally and economically sustainable way. We wanted to find a solution which all parties were happy with and really bought into.”

The first step was liaising with the Environment Agency to understand the catchment, and then Kelly had to identify the farmers in the catchment together with the individual yards and sites, in particular those used for pesticide handling and filling sprayers. She then contacted Charles Bentley from ADAS who met with each farmer and designed appropriate solutions to prevent pesticide pollution according to the risk on each farm.

“Every farm is unique and every farmer is an individual, so there are a range of options that we have employed,” stressed Kelly. “All seven farmers that we are working with have really welcomed the collaborative catchment management approach and working with us to ensure we put a solution in place.”

On-farm solutions

The solutions range from a drip tray which was provided to a small unit using spray contractors who don’t generally fill up in the catchment, to fully enclosed pesticide handling facilities. Elsewhere a bunded area was provided where any drips or spills are contained in a catch pit which is then regularly emptied by a chemical waste disposal contractor. On another site the farmer was provided with a biobed where the farmer can fill up and wash out the sprayer containing everything within the biobed.

One of the biggest investments took place at nearby Northlands Farm belonging to H.H. James & Son. John James and his son William farm around 1,200 acres of their own, while share and contract farming takes the total area up to 3,000 acres. The arable unit grows cereals, oilseed rape and sugar beet, as well as vining peas destined for Bird’s Eye, and some land is let out for carrot and potato production, with the furthest blocks of land up to ten miles away from the home farm at Winterton.

“Before we had this pesticide handling facility we would fill the sprayer up in the open yard with chemicals being taken to the mixing point from the pesticide store on a trolley,” explained John James. “This was perfectly safe for the operator, but was not as efficient as it needs to be, and was also repeated in our other satellite yards.

“We now have a safer and better working environment for our operator, and we can relax in the knowledge that when we are mixing, if we have a spill or splash of chemical it will be contained within the bund wall of the building and not lead to damage of the environment or the water supply.”

He adds that the purpose-built building, which also includes a frost-free pesticide store and a biofilter system to treat water from the catch tank, gives the farm a greater level of security for expensive chemicals and the sprayer itself. “After spraying, the sprayer can be left in the building and any chemical which may drip from it is captured,” added John. “To be able to wash or rinse the filter and the nozzles of the sprayer inside the building knowing that the washings will go through the biofilter is very reassuring and I’d like to thank Anglian Water for building this pesticide handling facility.”

A sceptic might wonder why a company like Anglian Water has built such on-farm facilities, but for the company the economic argument is simple and covered, bunded buildings are much cheaper than a complex plant to try to remove pesticide residues.

At Northlands Farm the company laid the concrete down and built the building, including a second roller-shutter door to allow forklift access. The contents of the catch pit are automatically pumped back into the biofilter – three large plastic boxes each containing a mixture of straw, soil and compost. The fluid drains through each of those boxes before being stored in a tank and applied to land via irrigation under an Environment Agency approval.

“This collaborative approach has helped us to reopen Winterton WTW and we are now working with the University of Lincoln to set up a demonstration site which farmers can visit to look at the on-farm pesticide treatment options available such as biofilters, biobeds and the Heliosec system,” said Kelly, who anticipates that the facility will open later this year.

She added that there was an extra personal sense of success for her seeing the completion of the project: “On my first day at Anglian Water in March 2015 I had a meeting about Winterton and what solutions we had. I’m really proud to have promoted catchment management and to seeing Peter reopen the water treatment works three years later, having supported the farmers in the area.”