COPY RIGHTS : TO AVOID COPYRIGHT VIOLATIONS, ALL POSTS ARE SHOWN ALONG WITH SOURCES FROM WHERE ITS TAKEN. PLEASE CONTACT ME IN MY EMAIL SALEEMASRAF@GMAIL.COM , IF YOU ARE THE AUTHOR AND YOUR NAME IS NOT DISPLAYED IN THE ARTICLE.THE UNINTENTIONAL LAPSE ON MY PART WILL BE IMMEDIATELY CORRECTED.

I HAVE SHARED ALL MY PRACTICAL WATER TREATMENT EXPERIENCES WITH SOLVED EXAMPLE HERE SO THAT ANYBODY CAN USE IT.

SEARCH THIS BLOG BELOW FOR ENVO ,COMPACT STP,ETP,STP,FMR,MBBR,SAFF,IRON,ARSENIC,FLUORIDE,FILTER,RO,UASB,BIO GAS,AERATION TANK,SETTLING TANK,DOSING,AMC.

SEARCH THIS BLOG

Saturday, January 07, 2017

Constructed wetlands for sewage treatment

A traditional septic tank or DEWATS will be  the primary means of treatment. The effluent from the septic tank / DEWATS can then flow to secondary  constructed wetlands and even tertiary treatments with a combination of reeds, typha, and sphagnum.
constructed wetlands for sewage treatment

Sewage Treatment all over the world requires large amounts of energy and/or chemicals to treat the waste water.There are a number of solutions to lessen the waste water load while at the same time producing a net benefit. Systems that include the collection of urine to be used as fertilizer and methane digesters that create fuel from feces [see ‘Biogas).Another solution — constructed wetland filtration systems for homes, communities, and industrial sectors — are efficient in both processing ability and energy requirements.The economic and environmental benefits of constructed wetlands filtration systems for small scale use are recognized in chemical- and odor-free treatment, creation of habitat, low setup/maintenance costs of the system, as well as a number of other natural benefits.



In-ground installations are usually of the horizontal flow variety. This means that effluent enters at one end of a bed and flows, horizontally, under the surface of the bed (gravel, sand, etc). The micro organisms clean the water as it flows through, eventually exiting at the opposite end of the container as treated water.
To install a basic bed, simply dig an appropriate sized hole for your application and fill it with a liner to prevent any waste-water from seeping into the environment. The beds should be deep enough to accommodate at least 30cm of water depth. Fill the bed with gravel, sand, etc. Another few centimeters of substrate above this 30cm area is suggested to accommodate the variance in the water levels that result from rains or heavy use of the waste-water system.

The level of the water can be allowed to rise higher than the substrate, and can even be maintained to create a pond like environment by allowing the water to flow on the surface rather than in the subsurface.

Container
Vertical flow systems instead introduce effluent through the top of the container. Gravity then feeds the effluent down through various layers of filtration-assisting substrates. The container traps oxygen and aids in breaking down ammonium. Vertical flow units can process stronger effluents in a smaller footprint than horizontal flow units. Combination systems can be installed to achieve even higher levels of filtration.

REED
Phragmites australis is one of the main wetland plant species used for phytoremediation water treatment.
Waste water from lavatories and greywater from kitchens is routed to an underground septic tank-like compartment where the solid waste is allowed to settle out. The water then trickles through a constructed wetland or artificial reed bed, where bioremediation bacterial action on the surface of roots and leaf litter removes some of the nutrients in biotransformation. The water is then suitable for irrigationgroundwater recharge, or release to natural watercourses. 

Micro organisms
The microscopic life in the bed is a main processor of the pollutants. While living in the substrate and oxygen-rich root systems, these micro organisms metabolize the chemicals in the effluent, effectively mineralizing them. With longer processing times, even hard to remove pollutants such as polycyclic aromatic hydrocarbons (PAH), polychlorinated biphenyl (PCB), dyestuffs, amines and glycols can be treated. At the end of the first Gulf War, oil polluted sands in Kuwait were treated with oil metabolizing organisms that live on the roots of the plants in the area.

Reed
The 4m tall common reed, Phragmites australis, is most commonly used in these wetland filter systems, mimicking the natural habitat of flood plains and estuaries. They have the most extensive root system for micro organisms to colonize. This root system increases the porosity of the substrate in which it is grown, resulting in a patchwork of aerobic, anoxic, and anaerobic conditions. There are many other varieties of reed that can thrive in just about any climate. During the growing season the chemical-resistant reeds themselves can account for about 15% of the pollutant removal, taking up and concentrating pollutants. Take proper care to dispose of the tainted reeds; avoid feeding them to livestock and the compost heap if pollutant levels are high.

Reeds can be good for finishing off the treatment of effluent to help reach regulatory levels, or to deal with seasonal use. Off season use, as in a caravan park, can mitigate runoff entering sensitive water courses while guests are using the property whilst still allowing the treated water to eventually reach its water course.
When establishing the reed bed, weeding will likely be required until the reeds have completely colonized the bed. Ideally 70% or more of the bed will be covered with reeds. The other 30% should include some combination of sphagnum or typha for best results. After 3-5 seasons the reeds can be cut back and allowed to regrow from their rhizomes.

No comments: