Technical and economical evaluation of UASB reactor’s substitution

Lake Utopia paper mill as part of the J.D. Irving, Limited (JDI) is believed to be one of the leading mills in preserving the environment. Specifically water quality is very essential for the mill since the waste water of the mill is currently depleted to the Letang estuary after treatment. The mill production has been increased dramatically over the last twenty years. The total BOD level in the waste water to treatment plant has also increased significantly with the increase of mill paper production. The hydraulic loading rate of the UASB reactors is about 30 kg COD/m3/Day (20 kg removable COD/m3/D) which is almost double of max design value of 15 kg COD/m3/D. UASBs are designed to receive influent of less than 500 ppm solids, but our influent has over 2000 ppm suspended solids constantly. The other issue that the

anaerobic plant is faced with is the build-up of calcium carbonate in the reactor sludge which occupies the reactor volume and decreases its efficiency. Due to these various reasons, this project is intended to provide the mill with the most efficient solution to its waste water treatment system among the possible options. So far installation of new reactors which is not sensitive to incoming suspended solids and can handle higher hydraulic loads of waste water is proposed.

UASB reactors found widespread usage since their development in 1970s. However since then these reactors have been modified or some other reactors e.g. ADI hybrid reactors, IC reactors, EGSB (extended granular sludge bed) reactors etc. have been introduced based on the same idea to improve UASB properties (size, circulation, COD handling capacity…). Many publications have analyzed different methods for improving anaerobic waste water treatment systems in recent years including

comparison of various reactors. Some of the methods have been implemented in industry. This area still is being investigated constantly.

It is anticipated at least two publications will be derived from the present work, which gives the detailed system analysis of UASB reactors/others related to the Lake Utopia paper operations.

The duty of the intern is to investigate the system thoroughly, find other effective solutions and also analyze the solutions feasibility and economy and other aspects. At the end, it is mentionable that the Irving corporations have always had close connections with the University of New Brunswick and sought implementation of new knowledge in industry through this.

Faculty Supervisor:

Dr. Yonghao Ni

Student:

Mehdi Afrousheh

Partner:

Lake Utopia Paper Mill

Discipline:

Engineering - chemical / biological

Sector:

Pulp and paper

University:

University of New Brunswick