AU2004100164A4

AU2004100164A4 - A recirculating evapotranspiration channel for on site wastewater treatment and reuse

Info

Publication number: AU2004100164A4
Application number: AU2004100164A
Authority: AU
Inventors: Benjamin Mark Kele
Original assignee: BENJAMIN KELE
Current assignee: Kele Benjamin Mark Mr
Priority date: 2004-03-05
Filing date: 2004-03-05
Publication date: 2004-04-22
Anticipated expiration: 2012-03-05

Description

Australia Patents Act 1990 Complete Specification Innovation Patent THE KEWT WASTEWATER TREATMENT AND RECIRCULATING EVAPOTRANSPIRATION

CHANNEL

The following statement is a full description of this invention, including the best method of performing it known to me: 24 AR 2004 THE KEWT WASTEWATER TREATMENT AND RECIRCULATING

EVAPOTRANSPIRATION

CHANNEL

On-site wastewater treatment and reuse systems have a history of failure. Wastewater treatment systems need to remove potential pathogens and environmental pollutants. This failure can put public and environmental health at risk because of the exposure to insufficiently treated effluent. I designed and assessed an on-site wastewater treatment system that safeguards public health and meets ecologically sustainable development guidelines. The technology is called the Kele Effluent Wastewater Treatment (KEWT) system.

The wastewater generated first undergoes primary treatment, either through an all-waste septic tank, or separately in a blackwater septic and a greywater vertical greasetrap. The primary treated effluent then flows through an in-line filter into a holding tank. The effluent from the holding tank is pumped, aerated by a venturi valve, and enters a selfcontained impervious channel (see Cross-section of KEWT channel).

The channel length can be constructed of concrete or plastic but it must be impervious.

The channel can be installed in sections or in one continuous length. Sections must be a minimum of three metres long and 400 mm deep. Each length of channel is installed level and sunk at least 200 mm into the ground. A continuous length of channel has a fall of mm after every three metres. Sections of channel have a 25 mm fall between them. The length of channel used in each instance depends on the volume of wastewater generated at each specific site. A slotted PVC pipe runs the length of the channel. The pipe is surrounded by aggregate, which is designed to act as a gravel-filter and a media for a biofilm. This pipe is covered with approximately 80 mm of 10 mm aggregate. The aggregate is comprised of a mixture of zeolite, scoria, and blue metal. These aggregate materials provide a substrate for a biofilm that provides treatment as well as being involved in chemical reduction through their specific cation exchange capacities.

A sand layer covers the aggregate layer and provides a highly porous barrier between the gravel-filter and the soil-bed. The sand layer removes solids from the effluent and provides another medium for a biofilm. The channel is filled with a sandy-loam soil.

Suitable soil can be imported for use in the KEWT channel if the soil at the site is inappropriate for the long-term application of effluent. The soil is mounded over the channel with the highest point of the mound being at least 200 mm over the top lip of the concrete pot.

The channels are then planted with a specific selection of terrestrial macrophyte plant species. The effluent moves from the gravel-filter into the soil-bed, where it undergoes soil and rhizofiltration and ultimately is reused through transpiration. Any effluent not absorbed by the soil or reused by the plants enters the return line and goes back into the holding tank from the channel (see KEWT System diagram). The dimensions of the channel can be changed depending on the requirements of the site and the volume of wastewater generated.

The holding tank is sized so that it has sufficient capacity to retain at least 48 hours worth of wastewater production. The holding tank incorporates a timer and alarm for the pump, a low-water feed, and an emergency form of effluent disposal. The timer allows for the delivery of regulated doses of effluent to the transpiration channel at specific times, to avoid complete saturation of the soil.

The alarm is fitted to give warning of pump failure. The low-water feed is required so that in times of reduced wastewater production, sufficient soil moisture is retained to support growth of the plants. Keeping the soil moist reduces the risk of roots penetrating the terra-firma matting in search of water.

In the event of system failure, such as pump breakdown, or excessive wastewater production, a safe temporary alternative for disposing of the excess effluent from the system is provided. The emergency effluent disposal can be in the form of a soakage drain or other system depending on the requirements of the site. The system meets the requirements for the treatment and subsurface reuse of on-site domestic wastewater according to the AS/NZS 1547:2000 and the Queensland on-site sewerage code.

The system keeps the effluent underground in a contained impervious channel during treatment. This means that people and the external environment cannot come into contact with the effluent; thus safeguarding public and environmental health.

The KEWT channel is the first time a gravel filter, cation exchange capacity treatment, sand filter, soil filter, biofilm treatment, rhizofiltration, and evapotranspiration reuse have been combined into the one treatment and reuse system in a contained impervious channel that is recirculatory. The KEWT system holding tank has been specifically designed to meet the requirements of the KEWT channel.

Claims

1. A on-site wastewater or effluent treatment and reuse system called the KEWT system comprising a contained channel that recirculates effluent through an incorporated gravel filter, cation exchange capacity treatment, sand filter, soil filter, biofilm treatment, rhizofiltration, evapotranspiration reuse, and attached holding tank.

2. The tanks and channels according to claim 1 are constructed and connected with impervious materials that do not allow the leaching of effluent from the KEWT system downwards into the environment.

3. A KEWT system holding tank that according to claim 1 that incorporates a pump, a pump timing switch, a aeration device; such as a venturi valve, a low water feed, an alarm, and an emergency overflow.

4. The KEWT channel according to claim 1 is planted with a specific selection of terrestrial macrophyte plant species recommended through the research undertaken. The KEWT system can be substantially as herein before described with reference to figures labeled Cross section of KEWT Channel and KEWT system. Ben Kele 5/3/04