Pulp waste reply

Ruapehu Bulletin, Volume 9, Issue 427, 10 March 1992, Page 4

Pulp waste reply

• Winstone Pulp is happy to reply to "Concerned's" question on what happens to the waste by-products produced at our Karioi Mill. Both solid and liquid by-products are produced from the pulping process. The major solid waste is bark. This is bumed in a highly efficient, low smoke, bark burner, to provide heat for drying the pulp. This is the only significant air emission from the Mill apart from steam. So far as the air goes this is a very "clean" pulping process. The non combustible solid waste, dirt, stones ash and effluent sludge are used for landfill. The volume of liquid effluent produced is also very low compared with other processes used. For every tonne of pulp produced we use 10 tonnes of water. Chemical pulp mills like Kinleith and Tasman use over 60 tonnes of water per tonne of pulp produced. The waste water from our process, which has been used for washing the pulp, contains dissolved wood products, dirt, and some fibre. This water then goes through five stages of treatment prior to discharge into the Whangaehu River. Treatment consists of screening, two stages of settling for solids removal, activated aeration for five days followed by a final settling stage. The annual operating cost of our effluent treatment system is over quarter of a million dollars. The effluent is tested on a daily basis and regular monitoring of the river is also conducted. It should be noted however that for a great deal of the time the river is naturally discoloured and is very acidic due to its source at the Crater Lake of Ruapehu. Turnpage5

Pulp effluent

From page 4 For this reason there is very little life in the river either upstream or downstream of our discharge. Winstones is working in close co-operation with the ManawatuWanganui Regional Council, as the Natural Resource Guardians, on ways to further reduce the impact of our efflu-

ent on the appearance of the river. Winstone Pulp International is committed to acting responsibly towards people and the environment. Thank you "Concerned" for your interest in our Mill. I hope this has helped to enlighten you.

Philip

Wilson

Technical Manager