Environmental impact of Valaichchenai paper mills effluen

Abstract

The paper mill situated at Valaichchenai in the Eastern province provides most of Sri Lanka's requirement of paper. A general opinion among the public is that, the effluent from the Valaichchenai paper mill pollutes the lagoon. Therefore, a necessity arose to monitor the level of pollution in the Valaichchenai lagoon. Samples were collected at a distance of about 10 m from the shore and at a depth of two feet for a period of seven months (September 96 - March 97) from raw water (Vahaneri)which is used for the paper manufacture, paper machine outlet and Valaichchenai lagoon where paper machine outlet is mixed. The pH, conductivity, salinity and turbidity were measured by using portable meters.Standard methods were used in the determination of anions, total suspended solids (SS), trace elements, dissolved oxygen and biological oxygen demand (BOD). The results of the analysis elucidate that, the parameters such as pH, salinity, BOD, the anions (S2~, F~, NOs~, PO±3~') and the concentration of trace elements were within the tolerance level in all the samples tested. Dissolved oxygen (DO) concentration (6.2-6.5 mg/l) was in the tolerance range for lagoon and raw water. Lagoon sample show high turbidity (>500 mg/l) and this condition may be a drawback for the survival of prawns and other living organisms. However, the seasonal rainfall enables a certain dilution of the pollutants to a level, which helps to prevent the death of living organism. The recorded values of SO^~ and CT~ for lagoon were 130 - 160 mg/l and 1500 - 3000 mg/l respectively.