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Greywater Management

► Full Grey Water Management Report

The environment is high on the agenda at all levels of government, industry and public opinion. Whether the issue is global warming, recycling or the protection of groundwater stocks, environmental legislation is impossible to avoid or ignore.

When it comes to protecting our groundwater, the Environment Agency is becoming far more vigilant. Authorities developing new cemeteries or extensions will encounter stringent rules and guidelines that have to be complied with before planning can proceed.

But many burial authorities, particularly if they have not undertaken any cemetery development work recently, are unaware of some of the groundwater and surface water protection directives they should be compliant with.

Whilst many millions of pounds are spent on memorial inspections and repairs as part of an overall health and safety policy, there is little consideration given to fulfilling the authorities’ legal obligation to protect groundwater. However, groundwater protection is statutory under the Water Resources Act. Failure to comply can lead to prosecution if ground or surface water are subsequently polluted. The EA have laid down strict guidelines for the development of new cemeteries, which include but are not limited to the following:

  • Graves should not hold any standing water when dug
  • There should be at least 1 metre between base of grave and water table; more if the soil has high infiltration rates
  • Graves should be at least 250m away from wells and potable water supplies
  • Pumping out of graves and discharging “grey” water directly or indirectly into surface or groundwater sources if found to be polluted is an offence under the Groundwater Regulations 1998
  • No burials within 10 meters of land drains

During the winter months, many authorities pump water out of newly opened graves, often to within a few minutes of the cortege arriving, hoping that the burial ceremony takes less time to complete than the speed of the water to re-enter the grave!

There are a number of reasons why water enters graves. If is not preventable it is a manageable problem – but it must be managed within the guidelines of the law.

It is important therefore, to determine where the water is coming from. There are usually three main sources:

  • Surface water (surface run-off/perching)
  • Ground water (rising water tables and suspended water tables)
  • Inter grave seepage

Grey water and drainage problems can be avoided. Simple management techniques can save tens of thousands of pounds in engineering costs, and a well designed drainage scheme can be both functional and affordable.

Attenuation Products

In some cases where there is a risk of leaching especially in coarse or fractured soils such as sandy, stoney or chalk soil formations or where water tables are near to grave depth, the use of attenuation material can help reduce rapid leaching. Polluting compounds associated with decay process such as ammonium, formalin and other organic pollutants can be absorbed by attenuation compounds which provide a buffer protecting the groundwater below. Attenuation materials include smectite and zeolitic substrates or material of high carbon content such as certain organic composts.

These attenuation materials have very high Cation Exchange Capacity (up to 150 meq/100gms), for example just 1 gram smectic clay may have a reactive surface area of 80 square meters compared to a few square centimetres in a gram of sand. An equivalent 25 mm depth of smectite clay could equate to a depth 2000 mm of sand in terms of their comparative attenuation properties!

These materials can certainly help in situations where high leaching soils pose a potential threat.
Smectite compounds have been advised by the EA for use as an attenuation medium in Southwick Cemetery in West Sussex where thin soils overly a chalk aquifer. CDS have developed “10u8 Z Plus” for the attenuation and reduction of polluting decay compounds. CDS are further researching other materials that have these properties.