New wastewater tests recommended
Marlborough wineries disposing of wastewater on to land are being advised to do tests to see if this could affect soil structure.
Marlborough District Council soil scientist Colin Gray told the council environment committee meeting on Friday that many wineries disposed of wastewater on to land, which the council encouraged.
However, research showed the sodium and potassium from chemical cleaning products and grape lees could make soils become impermeable, causing the liquids to pool on the surface.
The council commissioned AgResearch to study the probable impact of winery wastewater disposal on Marlborough soils, including recommendations on what should be measured and acceptable levels, he said.
Testing found that the mostly silt and sandy soils in Marlborough winemaking districts were probably not very susceptible to this problem, Mr Gray said.
However, AgResearch suggested that when the council updated its resource management plan, it include a requirement that wineries pouring wastewater on to land should routinely test for electrical conductivity and check that sodium, potassium, magnesium and calcium were below the levels that affected soil permeability. Committee chairman Peter Jerram said he would take the suggestion to the plan review sub-committee.
The Marlborough Express