Magnetic aminated lignin/CeO2/Fe3O4 composites with tailored interfacial chemistry and affinity for selective phosphate removal

Abstract This paper presents bench scale experimental results on the electrolysis of raw domestic wastewater. Studies carried out with consumable electrodes are discussed. A mathematical model of a small electrolytic sewage treatment unit for individual household application is developed. The energy consumption and cost of such a device are discussed. Electrolysis can be described as a process in which chemical reactions are induced at each electro-liquid interface by applying an external electrical energy source to a system of electrodes immersed in a liquid. This paper deals only with electrolysis where a direct current power supply is used as the energy source. The process is governed by Faraday' s two laws on electrochemistry. The fundamental process parameter is the electrical charge density, measured as coulombs per litre (c/1) of wastewater treated. There are two basic types of electrolysis depending on the choice of anode material. When the anode is made of dissolvable metallic material such as iron, stainless steel and aluminum, the metal dissolves and goes into the sewage as metallic ions and forms hydrated metallic oxides which act as flocculating agents. The amount of metal dissolved is proportional to the quantity of electrical charges supplied to the system. Results from a series of batch experiments showed that electrolysis with consumable electrodes is capable of removing significant amounts of organic pollutants. Total organic carbon (TOC) removal was found to be a function of charge density. Phosphate removal efficiency of 90 percent or higher was achieved at a relatively low charge density of 240 coulombs per litre with either iron or stainless steel anodes. A mathematical model was derived in the conceptual design of a household electrolytic treatment unit. The model incorporates variables such as decomposition voltage of the electrodes and electrical conductivity of the wastewater as well as the physical configuration of the electrolytic cell. The energy requirement of such a unit can be calculated from the model. It is suggested in this paper that an electrolytic waste treatment unit could be an alternative to the septic tank and tile bed system in areas where the latter is not applicable due to poor soil and terrain conditions.

Download Full-text

A Promising Combination of Two Phosphate Removal Techniques: Biological P-Removal and the Crystalactor

Water Science & Technology ◽

10.2166/wst.1991.0321 ◽

1991 ◽

Vol 24 (10) ◽

pp. 329-332

Author(s):

P. M. J. Janssen ◽

J. H. Rensink ◽

E. Eggers

Keyword(s):

Phosphate Removal ◽

P Removal

Download Full-text

Dynamics of phosphorus and organic substrates in anaerobic and aerobic phases of a sequencing batch reactor

Water Science & Technology ◽

10.2166/wst.1994.0274 ◽

1994 ◽

Vol 30 (6) ◽

pp. 237-246 ◽

Cited By ~ 21

Author(s):

A. Carucci ◽

M. Majone ◽

R. Ramadori ◽

S. Rossetti

Keyword(s):

Sequencing Batch Reactor ◽

Municipal Wastewater ◽

Batch Reactor ◽

General Assumption ◽

Organic Substrate ◽

Operating Conditions ◽

Phosphate Removal ◽

Substrate Uptake ◽

Organic Substrates ◽

Polyphosphate Metabolism

This paper describes a lab-scale experimentation carried out to study enhanced biological phosphate removal (EBPR) in a sequencing batch reactor (SBR). The synthetic feed used was based on peptone and glucose as organic substrate to simulate the readily biodegradable fraction of a municipal wastewater (Wentzel et al., 1991). The experimental work was divided into two runs, each characterized by different operating conditions. The phosphorus removal efficiency was considerably higher in the absence of competition for organic substrate between P-accumulating and denitrifying bacteria. The activated sludge consisted mainly of peculiar microorganisms recently described by Cech and Hartman (1990) and called “G bacteria”. The results obtained seem to be inconsistent with the general assumption that the G bacteria are characterized by anaerobic substrate uptake not connected with any polyphosphate metabolism. Supplementary anaerobic batch tests utilizing glucose, peptone and acetate as organic substrates show that the role of acetate in the biochemical mechanisms promoting EBPR may not be so essential as it has been assumed till now.

Download Full-text

Operational Results of the Wolfsburg Wastewater Treatment Plant

Water Science & Technology ◽

10.2166/wst.1992.0496 ◽

1992 ◽

Vol 25 (4-5) ◽

pp. 203-209 ◽

Cited By ~ 7

Author(s):

R. Kayser ◽

G. Stobbe ◽

M. Werner

Keyword(s):

Wastewater Treatment ◽

Activated Sludge ◽

Nitrogen Content ◽

Total Nitrogen ◽

Nitrogen Removal ◽

Wastewater Treatment Plant ◽

Treatment Plant ◽

Phosphate Removal ◽

Total Nitrogen Content ◽

Activated Sludge Process

At Wolfsburg for a load of 100,000 p.e., the step-feed activated sludge process for nitrogen removal is successfully in operation. Due to the high denitrification potential (BOD:TKN = 5:1) the effluent total nitrogen content can be kept below 10 mg l−1 N; furthermore by some enhanced biological phosphate removal about 80% phosphorus may be removed without any chemicals.

Download Full-text