Land Disposal of Septage (Septic Tank Pumpings)

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.

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Degradation of Oil by Land Disposal

Water Science & Technology ◽

10.2166/wst.1987.0048 ◽

1987 ◽

Vol 19 (8) ◽

pp. 99-105 ◽

Cited By ~ 3

Author(s):

G. Tesan ◽

D. Barbosa

Keyword(s):

Nutrient Availability ◽

Filter Cake ◽

Test Procedure ◽

Pilot Scale ◽

Effluent Treatment ◽

Biological Degradation ◽

Chemical Fertilizers ◽

Land Disposal ◽

Micro Organisms

The work presented consists of a test procedure applied at a pilot scale using soil as a biological degradation agent. The experiments described were carried out with oily residues considered as wastes difficult to degrade by other means. The tests were applied to filter cake with activated clay containing 40% oil and oily residues from re-refining of lubricants to give white oils and vaseline. The effect of the amount of moisture is evaluated using a mechanical stirrer to improve the interaction between the wastes and microorganisms. The following are also evaluated: nutrient availability; incorporation of micro-organisms into the soil; introduction of chemical fertilizers; and, injections of sludge from effluent treatment plants.

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An improved small sewage treatment plant for biological purification of wastewater

Water Science & Technology ◽

10.2166/wst.1994.0575 ◽

1994 ◽

Vol 29 (12) ◽

pp. 23-29 ◽

Cited By ~ 3

Author(s):

G. Voigtländer ◽

E.-P. Kulle

Keyword(s):

Energy Supply ◽

Sewage Treatment ◽

Sewage Treatment Plant ◽

Treatment Plant ◽

Septic Tank ◽

Additional Energy ◽

Anaerobic Reactor ◽

Step Process ◽

Operational Costs ◽

Aerobic Reactor

The paper presents a small sewage treatment plant (package plant) operating without additional energy. Purification of sewage is achieved in a three-step process: sedimentation tank, anaerobic reactor and wastewater pond or aerobic reactor. The efficiency of the anaerobic reactor - in contrast to the efficiency of a common septic tank - is significantly increased by using fixed biomass systems. Further degradation of sewage compounds by adhering microorganisms occurs in pond or aerobic reactor. The bed for the aerobic biomass is made of a semipermeable plastic film and arranged in order to ensure simultaneous supply of oxygen. The three pilot plants are showing different results. The main aims of research i.e. lowering of operational costs, energy supply, minimizing of maintenance expenditure and cleaning work, reliability of degradation efficiency have been achieved so far for the anaerobic reactor.

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Clay liner materials for land disposal of hazardous non-metal wastes

Water Science & Technology ◽

10.2166/wst.1996.0154 ◽

1996 ◽

Vol 33 (8) ◽

pp. 71-77

Author(s):

I. M.-C. Lo ◽

H. M. Liljestrand ◽

J. Khim ◽

Y. Shimizu

Keyword(s):

Sorption Capacity ◽

Organic Anion ◽

Surface Exchange ◽

Clay Liner ◽

Effective Removal ◽

Exchange Constants ◽

Anionic Species ◽

Surface Ligand ◽

Land Disposal

Simple land disposal systems for hazardous and mixed wastes contain heavy metal cationic species through precipitation and ion exchange mechanisms but typically fail by releasing soluble organic and inorganic anionic species. To enhance the removal of anions from leachate, clays are modified with coatings of iron or aluminium cations to bridge between the anionic surface and the anionic pollutants. A competitive surface ligand exchange model indicates that surface coatings of 10 meq cation/gm montmorillonite under typical leachate conditions increase the inorganic anion sorption capacity by at least a factor of 6 and increase the intrinsic surface exchange constants by more than a factor of 100. Similarly, metal hydroxide coatings on montmorillonite increase the organic anion sorption capacity by a factor of 9 and increase the intrinsic surface exchange constants by a factor of 20. For historical concentrations of non-metal anions in US hazardous and mixed waste leachate, sorption onto natural clay liner materials is dominated by arsenate sorption. With cation coatings, anion exchange provides an effective removal for arsenate, selenate, phenols, cresols, and phthalates. Engineering applications are presented for the use of modified clays as in situ barriers to leachate transport of anionic pollutants as well as for above ground treatment of recovered leachate.

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