Treatment of domestic wastewater in an up-flow anaerobic sludge blanket reactor followed by moving bed biofilm reactor

The performance of a laboratory-scale sewage treatment system composed of an up-flow anaerobic sludge blanket (UASB) reactor and a moving bed biofilm reactor (MBBR) at a temperature of (22-35 A degrees C) was evaluated. The entire treatment system was operated at different hydraulic retention times (HRT's) of 13.3, 10 and 5.0 h. An overall reduction of 80-86% for CODtotal; 51-73% for CODcolloidal and 20-55% for CODsoluble was found at a total HRT of 5-10 h, respectively. By prolonging the HRT to 13.3 h, the removal efficiencies of CODtotal, CODcolloidal and CODsoluble increased up to 92, 89 and 80%, respectively. However, the removal efficiency of CODsuspended in the combined system remained unaffected when increasing the total HRT from 5 to 10 h and from 10 to 13.3 h. This indicates that, the removal of CODsuspended was independent on the imposed HRT. Ammonia-nitrogen removal in MBBR treating UASB reactor effluent was significantly influenced by organic loading rate (OLR). 62% of ammonia was eliminated at OLR of 4.6 g COD m(-2) day(-1). The removal efficiency was decreased by a value of 34 and 43% at a higher OLR's of 7.4 and 17.8 g COD m(-2) day(-1), respectively. The mean overall residual counts of faecal coliform in the final effluent were 8.9 x 10(4) MPN per 100 ml at a HRT of 13.3 h, 4.9 x 10(5) MPN per 100 ml at a HRT of 10 h and 9.4 x 10(5) MPN per 100 ml at a HRT of 5.0 h, corresponding to overall log(10) reduction of 2.3, 1.4 and 0.7, respectively. The discharged sludge from UASB-MBBR exerts an excellent settling property. Moreover, the mean value of the net sludge yield was only 6% in UASB reactor and 7% in the MBBR of the total influent COD at a total HRT of 13.3 h. Accordingly, the use of the combined UASB-MBBR system for sewage treatment is recommended at a total HRT of 13.3 h

Anaerobic Treatment of Concentrated Black Water in UASB Reactor at a Short HRT

This research describes the feasibility of applying a UASB reactor for the treatment of concentrated black (toilet) water at 25 °C. On average 78% of the influent load of COD at an HRT of 8.7 days was removed. Produced methane can be converted to 56 MJ/p/y as electricity and 84 MJ/p/y as heat by combined heat and power (CHP). Minimum reactor volume at full scale was calculated to be 63L per person (for black water containing 16 gCOD/L produced at 5 L/p/d) and this is more than two times smaller than other type of reactors for anaerobic treatment of concentrated black wate

De invloed van het EG-recht op het Nederlands burgerlijk recht

Het doel van de cursus is, enerzijds, de deelnemers bewust te maken van de toenemende invloed van het recht van de EG op het Nederlandse Burgerlijk Recht, en, anderzijds, de deelnemers leren om te gaan met de doorwerking van het EG-recht in de nationale rechtsorde. De cursus en het materiaal bouwen voort op de basismodule Europees Gemeenschapsrecht

Polymer and alcohol-based three-phase partitioning systems for separation of polysaccharide and protein

BACKGROUND: Natural polymers are macromolecules produced by living organisms, and they have a wide range of applications and relevance for the development of a circular economy. However, large-scale production continues to be hindered by several factors, such as downstream processing. In this work, three-phase partitioning (TPP) systems were investigated for separation of model polysaccharide (dextran, alginate, and gum arabic) from protein [Bovine serum albumin (BSA) and lysozyme]. The recyclability of the phase-forming compounds used to form the extractive platform was assessed by ultrafiltration (UF). This study contributes to the development of production processes for biopolymers from fermented waste by proposing an effective separation technique for fractionation of biopolymers. Such biopolymers are often collected as mixtures, but with the studied approaches, fractionation of polysaccharides from proteins may also be employed. With the chosen systems, the scope of TPP systems is expanded by using another class of phase-forming compound (polymers); in addition, UF was studied as a versatile regeneration approach. RESULTS: Within the TPP approach, the best separation of dextran from BSA was achieved using TPP systems composed of 25 wt% polyethylene glycol (PEG) + 25 wt% K3C6H5O7 and 36 wt% EtOH + 10 wt% K3PO4, in which more than 95% of dextran and BSA were found as precipitate and partitioned to top phase (PEG or EtOH-rich), respectively. By using other model compounds, it was found that the molecular weight and charge of the biopolymer play a key role in the yield and selectivity of TPP systems. Finally, by using ultrafiltration/diafiltration, about 99% of the ethanol and phosphate salt used to form the extractive platform could be retrieved in the permeate stream. CONCLUSION: The high extraction yields, good selectivity, and recyclability of phase-forming compounds confirm the potential of polymer-based and alcohol-based TPP systems to fractionate biopolymer mixtures.</p

MBR Technology: future research directions

Cutting down the operational costs of MBR technology will be the key driver for research. This article outlines some research areas and specific topics that potentially will contribute to lower costs. Special attention to these topics should be given the coming years. Long term research should focus on sustainable MBR concepts. A few innovative developments will be presente

Separation of polysaccharide and protein by ionic liquid-based extraction techniques

Biopolymers are natural macromolecules obtained from animal, plant and microbial sources, with the potential to be used in a wide range of applications. A key process step, which is still underdeveloped, is the downstream processing. In this work, water immiscible and water miscible ionic liquids (ILs) were investigated regarding their ability to fractionate a mixture of polysaccharide and proteins. Alginate and bovine serum albumin (BSA) were used as model compounds to mimic natural polymer crude extract. Phosphonium ILs composed of different anions (bromide, dicyanamide and phosphinate) were used as water immiscible ILs while imidazolium ILs, combined with phosphate salts to form biphasic system, were selected as water miscible ILs. In water immiscible IL systems, the partitioning behavior of biopolymers depended on IL's anions and there was formation of insoluble precipitate. The insolubility of precipitate in diverse aqueous and organic solvents hindered the processibility of water immiscible phosphonium IL for fractionation of biopolymers. The partitioning of biopolymers in water miscible ILs systems also depended on the IL's anion, as well the concentration of IL. Separation of alginate (yield = 90% and purity = 99%) from BSA (yield = 89% and purity = 99%) was best achieved by the [C4mim]Cl-based extraction system. After fractionation, regeneration of IL and salt used was carried out by ultrafiltration, with recovery yields up to 100%. The high extraction yields and recyclability of phase-forming compounds confirm the potential of water miscible ILs systems to fractionate polysaccharide and protein

Denitrificatie met opgelost methaan uit anaerobe vergisting: nieuwe mogelijkheid voor afvalwaterbehandeling

Huishoudelijk afvalwater bevat veel energie. Rioolwaterzuiveringsinstallaties hebben zodoende de potentie om energieproducerend te worden in plaats van energieconsumerend. Er zijn reeds initiatieven in gang gezet die zich richten op het terugwinnen van energie in de vorm van biogas door het vergisten van primair en secundair slib. Een meer directe route naar biogas is de anaerobe zuivering van het afvalwater. Het effluent van een anaerobe reactor bevat echter nog wel ammonium en opgelost methaan (een sterk broeikasgas). Beide kunnen omgezet worden met de recentelijk ontdekte DAMO-bacteriën: denitrificatie gekoppeld aan anaerobe methaanoxidatie. Dit biedt nieuwe mogelijkheden voor een energie-efficiënte afvalwaterbehandeling