|
|
|
|
3 ADVANTAGES
AND CONSTRAINTS OF REED BED TREATMENT TECHNOLOGIES 3.1 CONSTRAINTS
to the Technology
LARGE LAND AREA REQUIREMENT The requirement for a much larger land area compared to
other treatment technologies.
RUNNING - IN - PERIOD Many reed bed systems require a longer
running-in-period than other treatment technologies before they can achieve
their hill operational performance. This is especially so in systems using soil
based substrates, as their full hydraulic throughput is directly proportional to
the growth and climax development of the planted root zone. Also, particularly
harsh concentrations or constituents in the effluent can retard the growth and
climax development of the plants and their host micro-organisms. These factors,
singly or combined, mean that in some cases a 1 to 3
year period to complete commissioning is necessary. However, lead in times for reed bed systems to achieve
full design performance have continued to reduce over the years as new
developments in the make up of substrates, as well as synergistic integration
with other biotechnologies have been exploited. There are now many system designs which can achieve
their performance specification from day one.
SEASON AND WEATHER DEPENDANT ACTIVITIES DURING FEASIBILITY STUDIES AND
CONSTRUCTION OPERATIONS Several critical activities involving the use of plants
during feasibility and/ or pilot trials, as well as planting and soil operations
during the construction of systems, are seasonally constrained and weather
dependant. lt is possible to mitigate this constraint through the
use of glass-house laboratories, permanent test beds (fixed or mobile), use of
alternative substrates or soil conditioners, greater planting density and/or
large containerised planting stock.
POTENTIAL FOR MIS-OPERATION OF LIVING
SYSTEMS In common with other biotechnologies, reed bed
technology can only be successfully implemented and operated by clients who
genuinely appreciate and understand the constraints and advantages of living
systems. The risk of system mis-operation and associated
negative exposure can be overcome by giving appropriate frank advice and
recommendations to our clients at the feasibility stage, and through the
provision of post construction consultancy and supervision services, including
the training of client personnel and the supply of operating manuals.
NOT A STANDALONE SOLUTION TO EVERY TYPE OF WASTE PROBLEM Reed bed technology alone is not capable of providing
the optimum treatment solution to every type of waste problem. There are
effluents and sludges with concentrations and/ or types of constituents which
are too problematic or unsuitable for primary or secondary treatment in a reed
bed system. However, reed bed systems can be synergistically
combined with other technologies, especially other biotechnical systems, (such
as a second step to anaerobic digestion for effluents with very high COD levels),
so increasing the effective range of application for both technologies.
UNDERSTANDING AND ACKNOWLEDGING CONSTRAINTS
DRIVES FORWARD OUR INNOVATION AND COMPETITIVENESS As skilled professionals
committed to excellence, we want to deliver to our clients the overriding
benefits of reed bed technology, and therefore, we welcome the challenge of the
above constraints as a means to continuously drive forward our innovations and
competitiveness. 3.2 ADVANTAGES
of the Technology
ROBUST AND EFFECTIVE lt is easy for those unfamiliar with this technology to
underestimate the robustness and effectiveness of the natural processes
operating within such engineered ecosystems and their powerful cleaning and
recycling capability. The composition of micro-organisms in a reed bed system is
very versatile with more than 5,000 different types of bacteria compared with
200 - 300 in other biological treatment plants.
CONSISTENT DISCHARGE QUALITY Such engineered ecosystems have a superior capacity to
tolerate wide variations in effluent characteristics, and to withstand shock
loadings, without damage or disruption to treatment and so maintaining a
consistent discharge quality.
NO BY-PRODUCTS Reed bed systems produce no noise or smells and no
sludges or other by-products with associated additional costs of disposal.
VERSATILITY A particular strength of the technology is that,
although it is not a general panacea for every waste treatment situation, it can
be used in many different ways for different purposes. lt can be used as primary
or secondary treatment for a wide variety of effluents and sludges. To date, we
have knowledge of the decomposition of some thousand compounds in reed bed
systems. Reed bed systems can be used to treat effluents which
are surprisingly concentrated as well as effluents with difficult pollutants too
dilute to treat by conventional means but which remain too dangerous to release
into the environment. Reed bed systems can be used to recycle water and even
precious contaminates which are bound into the substrate such as copper. They can also play a cost effective role in the
containment and treatment of storm-water overflows.
LONG LASTING WITH LOW OPERATIONAL & MAINTENANCE COSTS With little or no electrical or mechanical parts, reed
bed systems are long lasting, wear free and naturally regenerative. Being
self-regulating ecosystems, they are simple to operate without chemical
additives or complex electronic controls and require minimal staffing levels due
to their very low maintenance requirements. Consequently operational and energy
costs of reed bed systems are very low and system lifetimes are very long.
LOWER CAPITAL COSTS THAN ALTERNATIVE CONVENTIONAL
SYSTEMS Territorial authorities and companies choose reed bed
treatment systems on economic grounds. The capital costs of reed bed treatment
systems depend on the availability and proximity to the proposed site of natural
resources such as land, suitable clay, soils and substrate materials. Generally
speaking, the capital costs of reed bed systems are at least comparable to
conventional treatment technologies, and depending on circumstances can be up to
one third less than conventional treatment systems.
ENVIRONMENTALLY SAFE & BENEFICIAL Reed bed systems in their construction and operation
are environmentally benign, as in essence they are specially engineered
ecosystems, using substantially natural components to harness nature‘s own
powerful processes. The tall attractive reeds in such systems not only blend
pleasantly with the local landscape, but also offer considerable amenity and
wildlife conservation potential. As a spin-off benefit, reed bed systems can
recreate ,,natural“ wetland habitats which are otherwise fast disappearing
around the world, and for this reason alone their use is likely to be
enthusiastically supported by many influential people and organisations. |
|
|