Traditionally, waste management efforts have focused primarily on ?end-of-pipe? treatment methods which simply transfer pollutants from one medium to another; just moving the problem forwards. The energy costs associated with aerobic treatment have been low and disposal of sludge and wastes from industrial processes have been easy.
The adverse impacts of these wastes and/or pollutants on the environment have increasingly become a major concern of regulatory agencies and businesses. This leading to higher costs and a wrong perception by the public.
Another element leading to the increasing shortage of water in this region of the US and in many other regions of the globe in general, is the commonly accepted fact that water an abundant material is in the life of mankind. This conception of the importance of water changed in the second half of the 20th century. The necessity of guarding and conserving this natural resource of enormous importance is imperative today, and this not only for the wide spectrum of life but also for the industrial progress that is inherent to modern life. Especially with the Chinese giant entering the fast progressing industrial world. Industrial operations need water of high quality and in high quantity. These two parameters not only vary between different types of plants but also for different uses within each plant.

The food industry needs both. During the last two decades the brewing industry has shown increasing awareness for environmental protection and the need of sustainable production processes. In 2002 a new biological water treatment with anaerobic and aerobic system was taken into use by NBB. Combining anaerobic pre-treatment with aerobic post-treatment integrates the advantages of both processes amongst which reduced energy consumption (net energy production), reduced biological sludge production and limited space requirements, are the most important. The treatment system had to cope with a increasing flow of wastewater because of the growing success of NBB. If this growth is going to continue, the wastewater treatment will have to expand as well before reaching maximum capacity. Therefore NBB decided to expand the system, keeping the old aerobic system but replacing the anaerobic system by a Upflow Anaerobic Sludge Blanket. The start-up and fine-tuning of this anaerobic treatment is a long-term process. In order to get all the best opportunities for a stable teatment of the wastewater it is necessary to do a lot of testing. All testing activities are mentioned in this paper as well as a description of the treatment system, with special attention for the anaerobic treatment.

Abstract


New Belgium Brewing Company is a fast growing brewery in Fort Collins Colorado. The major ingredient of beer being water, it is of crucial importance to keep this resource clean and abundant. This can be accomplished by treating the water to a certain level before release in the municipal sewage system.

The treatment system at NBB is based on a anaerobic system of the ?upflow sludge blanket type?, meaning there is an upflow current leading the wastetwater through a blanket of anaerobic bacteria, consuming the brewery wastes for metabolism. After anaerobic treatment, the second step consists of aerobic treatment and finally sedimentation of sludge. This paper,however, focusses on the anaerobic system.

The startup of this latter is an interesting and unpredictable process. The first step of the startup consists of finding a good sludge compatible to the water profile of the brewery effluent. Once the sludge has been selected it can be innoculated in the UASB tank. From this point on, the sludge has to acclimatize, form a sludge blanket and finally grow. These steps are closely controlled by using laboratory based test kits. Especially the volatile fatty acids and COD values were significant since the importance of the fragile methanogenic bacteria population of the anaerobic system.

The results of the startup are very convincing. After only two weeks, all the parameters mentioned in the contract were largely met.

Conclusions:
In this chapter we will have a closer look at the results generated by the new UASB system. From the 24th of May on we can already see the UASB being stable, only 15 days after the innoculation date. The average COD coming out of the UASB after stabilization is 1095 mg/l. This value is less then half the COD value the Skjöldgas was performing (4978 mg/l in 2003; 2383 mg/l in 2004; 3219 mg/l in 2005). The efficiency of the UASB is much higher than the objectives. The objective concerning the COD was a minimum decrease of 80%, on average however the UASB performed much better. During the first 2 months (from the 24th of May till the 19th of June) an average of 94% of the CODt was consumed by the anaerobic system.
Figure 18 is giving an idea of the efficiency and activity of the UASB as well as the efficiency of the equalisation. One has to notice the difference of the COD between inlet and equalisation. The COD values of the equalisation are always lower compared to the COD values of the inlet. This is probably due to the settling of some parts able to get through the screen, leading to a ?loss? of COD. When the inlet water is entering the system, it is screened by a turbidity meter: a too high turbidity means too much TSS. The water is therefore sent to the emergency, this gives an opportunity to lower the high TSS by settling. The upper layer of the water in the emergency is then going to the equalisation basin, leaving a part of the COD in the emergency basin (the ?loss?).

The start-up of the UASB went very fast. The stabilization of the system was already obtained after two weeks. This is partially due to the good sludge.
In July and August the second important part was started: the fine-tuning. The temperature of the wastewater is lowered and a few new sludge activity tests were performed to watch the reaction of the UASB. The temperature was lowered from 37,5°C to 30°C; the spent yeast was added and the NaOH addition was stopped. Again a SAT was performed after giving the UASB some time to adapt.
The final step, called the performance testing was executed at the end of July and was positive. The parameters agreed upon in the contract were easily obtained.



Auteur: Joachim Kokken
Herkomst: Karel de Grote Hogeschool, Dept. IWT-Hoboken
Referentie: Referentie