INNOVATIVE BIOLOGICAL WASTEWATER TREATMENT
TECHNOLOGIES APPLIED TO THE TREATMENT OF BIOMASS
GASIFICATION WASTEWATER
John V. Maxham, Research Engineer
Will Wakamiya, Research Engineer
Water and Land Resources Department
Battelle, Pacific Northwest Laboratory
Richland, Washington 99352
One way of utilizing biomass as a renewable energy resource is to thermochemically
convert it into a gaseous fuel. During conversion, wastewaters are generated that will require
treatment prior to reuse in the production process of discharge to the environment. Application of appropriate wastewater treatment technologies is necessary at the pilot plant
stage of production technology development for the following reasons: (1) to factor wastewater treatment costs into estimates of costs for commercial scale production facilities;
(2) to assess environmental impacts and/or health risks of discharged effluents so that the
necessary permits for construction can be issued without excessive delays; and (3) to assess
impact  of recycled   effluents  on  commercial  scale process performance (if applicable).
The principal task of this U.S. Department of Energy (DOE)-sponsored research effort
has been to assess the technical feasibility of several promising process technologies for the
treatment of biomass gasification wastewaters (BGW) by conducting bench-scale treatability studies. Emphasis has been given to biological wastewater treatment technologies
since these technologies are typically more cost effective than physical-chemical treatment
alternatives for removal of organic substrates in high-strength wastewaters, provided such
wastewaters are amenable to biological treatment. Biomass gasification wastewaters do, in
fact, contain organic substrates (e.g., phenolics) that can be toxic to microorganisms or
inhibit their growth. However, with proper biological reactor startup procedures, it is often
possible to successfully acclimate microorganisms to wastewaters containing toxic or growth
inhibitory chemicals.
This chapter reports results obtained with applying three innovative biological wastewater treatment technologies to the treatment of both diluted and full-strength BGW samples. These technologies appear to represent a major technological advance in the biological
wastewater treatment area. They promise to dramatically reduce treatment time, cost,
energy consumption and/or sludge production while preserving the simplicity of operation
and mechanical reliability of conventional treatment process options.
WASTEWATER CHARACTERISTICS
All BGW samples used in the bench-scale treatment studies were generated by the SGFM
biomass gasifier at Texas Tech University in Lubbock, Texas. These samples were shipped
from Texas Tech University at approximately two-month intervals. When received, these
samples were composited and stored at 4 C. The total wastewater volume of a shipment
would range from 5-7 liters. Therefore, the size of the bench-scale biological treatment
reactors were specified as small as possible in order to conserve wastewater feed.
Table I presents a chemical analysis of the three full-strength biomass gasification composite wastewaters used in the biological treatment studies. The high TOC and COD values
indicate the BGW samples were highly concentrated in organic substrates. The low total
solids values (relative to the TOC and COD values) indicated that a large percentage of the
organic substances were volatile near the boiling point of water, and therefore were not
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