Biomedical subjects

D H J G Berends

Publications and source records attributed to D H J G Berends.

3 recordsLinked to original sources

PubMed2005

Boosting nitrification with the BABE technology.

Over the past years there has been a growing interest for compact, simple, low cost and robust technologies to upgrade wastewater treatment plants for nitrogen removal. The BABE (Bio Augmentation Batch Enhanced) technology is such a new concept. This patented system for biological treatment of sludge liquor - the effluent produced from digested sludge - uses a new principle, boosting the nitrifying bacteria in a side stream in such a way that the activated sludge in the main process is augmented. This augmentation increases the nitrification capacity of the wastewater treatment plant (wwtp). Experiments on a practical scale have demonstrated the effective and stable operation of the BABE technology. Model studies supported by the results of the full-scale tests showed that the technology can be applied in several situations, i.e. 1) introducing nitrification at high loaded wwtps; 2) enhancing nitrification at wwtps with incomplete nitrification; 3) enlarging denitrification at wwtps with complete nitrification. Most likely this year a full-scale application will be realized in the Netherlands at a wwtp with insufficient nitrification throughout the year.

Ammonia↗

PubMed2004

Full-scale application of the BABE technology.

Bio-augmentation can be used to obtain nitrification in activated sludge processes that operate at sub-optimal solid retention times. A side-stream process, the so-called BABE process that incorporates N-removal and augmentation of nitrifiers has been developed. The principle is to implement a nitrification reactor in the sludge return line, the so-called BABE reactor. This reactor can be fed with an internal N-rich flow (e.g. effluent from the sludge treatment). Hence the nitrification capacity of an activated sludge process can be augmented by the addition of nitrifiers cultivated in the BABE reactor. A full-scale test of the BABE technology has been at the treatment plant Garmerwolde in Groningen, the Netherlands. The set-up allowed comparing between three different lines: with the BABE reactor, without rejectwater and with untreated rejectwater. Based on this, the two important tasks (N-removal and inoculation) performed by the BABE reactor could be quantified. The results of the practical work in Garmerwolde showed a higher nitrification rate in the water line where the BABE reactor was implemented and also lower effluent ammonia. The experiments on a practical scale have demonstrated univocally the effective and stable operation of the BABE technology. In addition, sludge samples in different streams as well as from the BABE reactor were analysed with FISH technique. The FISH results illustrated the augmentation effect of the BABE reactor on the stream with the BABE reactor. A mathematical model, based on ASM1 model and implemented in AQUASIM was developed and used for simulating the treatment plant of Garmerwolde. The simulation results indicated that better effect of the BABE technology is expected at lower ambient temperatures and smaller volume of the BABE reactor. The BABE reactor could also allow for providing more space for de-nitrification in the main water line when nitrification is efficient enough.

Ammonia↗

PubMed2003

Bio-augmentation by nitrification with return sludge.

Bio-augmentation can be used to obtain nitrification in activated sludge processes that operate at sub-optimal solid retention times. In this study, we evaluated the potential of augmenting the endogenous nitrifying bacteria, by implementing a nitrification reactor in the sludge return line. This reactor can be fed with an internal N-rich flow (e.g. effluent from the sludge treatment) or with an external ammonium source. A mathematical model based on ASM1 was developed and used to evaluate the potential of this technique. The bio-augmentation studied here aimed to enhance the nitrification process of highly loaded activated sludge systems. A calibrated simulation model of a high loaded wastewater treatment plant in The Netherlands was used for this study. A side stream process (the named BABE process) was included in the simulation. This process was fed with the ammonia-rich water generated by sludge digestion and subsequent thickening by centrifugation (the so-called rejectwater). An external source (artificial) of ammonium was also considered to evaluate the differences between the two origins of ammonium. The results showed that with the augmentation process, high loaded activated sludge systems can achieve nitrification even at low winter temperatures. The best effect is obtained for systems operating at approximately 50% of the minimal SRT without augmentation. The use of an internal ammonia source is more effective than an external source. The results of this study give a quantitative basis for the design of process internal bio-augmentation processes and the effect on the N-removal capacity of the treatment plant.

Bioreactors↗