Characteristic Strength and Treatability of a Recycled Paper Mill Wastewater in a UASB Reactor

Abstract

The characteristic strength of wastewater from a recycled paper mill in Nairobi, Kenya and its suitability for treatment in a UASB (upflow anaerobic sludge blanket) reactor at ambient temperature were assessed. TheBOD5/COD relationship showedthat the wastewater is of high strength, biodegradable and has a potential to increase in strength with time. The effluent is acidic and deficient in basic inorganic nutrients such as nitrogen and phosphorus which are required for biological treatment. The effluent has less sulphate and total solids as compared to wastewater from paper mills using virgin wood pulp and is thus suitable for treatment by anaerobic process. In a UASB reactor, about 63 per cent COD removal and total biogas production rate of 0.2 l/g COD were attained at a load of 12 to 15 KgCOD/m3/day. A well-pelletized sludge was formed in the reactor over a period of 4 months.


(Journal of Civil Engineering, JKUAT: 2002 8: 61-78)