Description of the Autoflow System

Transcription

1 Description of the Autoflow System Introduction Autoflow seeks to recycle wastewater safely back into the environment. To do this Autoflow employs natural and, where possible, passive (non electric) processes to imitate nature in the treatment of wastewater. Our underlying philosophy is that there is no such thing as wastewater, rather we humans borrow water, use it and can return it in a way that nature can safely handle. Thus we are part of nature s water recycling process. An Autoflow system contains living organisms employed to perform the task of treating waste water and consists of five components: 1. Vermi tank utilises worms and other organisms to convert solid organic waste into compost. 2. Grey water tank utilises slaters and aerobic bacteria to filter and improve water quality. 3. Batch reactor/ dosing chamber utilises media (gravels) to filter waste water and doses it to the land application area. 4. Land application system (low pressure pipe, LPP) distributes waste water to the soil. 5. The receiving environment - a planted evaporation/transpiration field. An Autoflow system requires the two waste water flows - black and grey to be kept separate as they leave a dwelling. Black water enters the vermi tank while the grey water enters the grey water tank. By not mixing the two flows a higher water quality output from the Autoflow treatment process is achieved. 1

2 Autoflow Components: 1. Vermi Tank This tank receives and processes all organic waste and waste water from the kitchen and toilet(s). It is an aerobic tank which houses worms and other decomposers which break down the solid waste in black water. The solid waste entering the tank lands on the surface of the compost where decomposition takes place - as it does in the natural environment. This waste is eaten by the worms and converted to worm castings which are a valuable fertilizer and soil enricher. The vermicomposter produces no offensive odours because it is aerobic. Being aerobic also enables the decomposition process to happen a lot faster than a conventional anaerobic septic system meaning a smaller tank can be used (1500 litres). The compost and media inside the tank act as a natural filter (as they do in nature) for the black water stream. This reduces faecal coliforms, biological oxygen demand (BOD) and total suspended solids (TSS) in the black water - measures of water purity. Once filtered the black water flows into the manifold at the base of the vermi tank and onto the next treatment process. 2

3 Worms The worms used in a vermi tank are tiger worms; the ones typically found at the bottom of a compost bin. 1 kg of worms needs to be added to the soil inside the vermi tank when it is commissioned. Worms are ideal for the vermi tank as they consume human waste and paper from the toilet. They also consume food scraps, fats and grease from the kitchen water. This has the added advantage of eliminating the need for a grease trap. Substances toxic to worms include bleaches, ammonias, paint and petrochemicals which cannot be disposed of in an Autoflow system. Worms eat half of their own body weight per day and will reproduce to match the amount of waste material they are fed. In conditions of poor food supply the worms will move deeper into the tank, stop reproducing and hibernate. This makes the vermi tank very effective in situations where it will receive intermittent use such as a bach. We do however recommend an Autoflow system should not be left longer than four months without use. The vermi composter requires worm castings (compost) to be removed every three to six years. The worm castings form around the edge of the tank allowing fresh matter to land in the middle for processing. When digging out fresh matter does not need to be removed. 3

4 2. Grey Water Tank This tank receives and processes all grey water flows from the bathroom and laundry. Grey water is high in liquid volume but low in solids. The grey water is initially screened through a 6mm mesh on the top of the inside of the tank. Underneath the mesh is bark and gravel media which houses slaters and other bacteria which feed on the solids (soap, lint, body oils etc.) in grey water. Once filtered the grey water flows into the manifold at the base of the grey water tank and onto the next treatment process. Grey water tank 1500ltrs 4

5 3. The Batch Reactor The batch reactor is filled with media (stones and gravels) and further filters the waste water from the vermi and grey water tanks. The batch reactor contains a siphon (if there is enough fall) or a submersible pump and doses the waste water back to the land. Dosing means the batch reactor alternately fills and empties which draws oxygen into the media. This oxygen diffuses into the water as it enters and thus oxidises it. The best media to use are pea gravel, scoria or sphagnum moss. Tiny organisms live on the surface of these media and consume the small solids suspended in the waste water. The filling and emptying of the batch reactor allows these organisms to filter feed on nutrients as they enter the tank. Batch reactor 5

6 4. Land application system - low pressure effluent distribution (LPED) pipe To ensure the treated water is dispersed over the largest possible land surface area Autoflow uses a number of unique features within its land application system. Dosing The Autoflow dosing siphon or pump discharge the treated water from the batch reactor to the land application system. Dosing charges the entire delivery line system with water which ensures the largest possible surface area is utilised. Dosing also has the added advantage of allowing the soil a recovery period between doses. Manifold The manifold feeds the treated water leaving the batch reactor into each of the LPED delivery lines. This ensures that all the LPP lines carry the same amount of water. Low pressure effluent distribution - LPED - delivery lines The Autoflow LPED delivery lines carry the treated water from the manifold to land. They are usually 25mm or 32mm in dia. and pinned to the surface of the ground with stainless steel staples. Feed lines carry dosed water from the LPED delivery lines to cut lengths (cells) of 100mm diameter slotted drain coil buried in the ground. Feed lines The feed lines allow the LPED delivery lines to remain full of water. This gives the delivery line maximum pressure the whole time it is being dosed. Without the feed lines the LPED lines would lose effective pressure as they were first filled then emptied. Drain coil The Autoflow LPP system cuts the drain coil into cells (sections) of approximately 3m in length. The cells are placed into a dug trench, back filled at each end and covered with 100mm of bark, mulch, or soil. This method eliminates the problem with drain coil where water can flow along its length and saturate a low point. (See over). 6

7 5. The receiving environment The last step in an Autoflow system is a vegetated evaporation/transpiration field. This simply utilises nature s ability to take up water via plants and evaporate moisture via the sun. We encourage planting of the dispersion field. Used water is good for irrigation of fruit trees or wood lots as well as ornamental gardens. The dispersion field should not be used to grow leaf or root crop vegetables. 7