Other WWTP technologies
Sometime, depending on special requirements, for example extra high
SBR technology (sequence batch reactor)
The main SBR difference from conventional technology is that most processes including sedimentation is ongoing in the same tank. While there are several configurations of SBRs, the basic process is similar. The installation consists of one or more tanks that can be operated as plug flow or completely mixed reactors. The tanks have a “flow through” system, with raw wastewater (influent) coming in at one end and treated water (effluent) flowing out the other. In systems with multiple tanks, while one tank is in settle/decant mode the other is aerating and filling. In some systems, tanks contain a section known as the bio-selector, which consists of a series of walls or baffles which direct the flow either from side to side of the tank or under and over consecutive baffles. This helps to mix the incoming Influent and the returned activated sludge (RAS), beginning the biological digestion process before the liquor enters the main part of the tank.
The main benefit of the SBR system is high level of automation. Most processes (filling, removing and etc. are automated and it is good for smaller plants. But this benefit can also become the weakness, because in case of failure of any part of automation system (for example oxygen sensor ) the system becomes unstable.
MBR technology (membrane)
The main difference of MBR technology from conventional is use of ultrafiltration membrane units instead of secondary clarifiers. Because of ultrafiltration, the effluent quality (for suspended solids) is much higher, then in conventional systems, also no bacteria or viruses may past the membrane.
It is possible to operate MBR processes at higher mixed liquor suspended solids (MLSS) concentrations compared to conventional settlement separation systems, thus reducing the reactor volume to achieve the same loading rate. Simply due to the high number of microorganism in MBRs, the pollutants uptake rate can be increased. This leads to better degradation in a given time span or to smaller required reactor volumes. In comparison to the conventional activated sludge process (ASP) which typically achieves 95 percent, COD removal can be increased to 96 to 99 percent in MBRs.
Good example of usage of MBR reactors are coastal towns, where place of construction of WWTP is limited, and effluent requirements are more strict. Also with use MBR there is no need for additional disinfection of effluent.
But it should be clearly understandable, that MBR technology is always higher investments and higher operational costs comparing with traditional technologies. Usually higher operational costs are related to requirement to pump wastewater into MBR filtration units – due to high resistance of the membrane water cannot flow by gravity. Another requirement is constant membrane wash, where powerful wash water pumps shall be installed.
Our company can offer MBR technology based WWTP on request.
USBF technology (Upflow Sludge Blanket Filtration)
Upflow sludge blanket filtration in a prism or a cone shaped filter introduces a substantially higher specific rate of separation than other commonly used separation techniques, and it facilitates operation in the region of increased mixed liquor concentrations (as it provides a “filtration/flocculation” mechanism to prevent the discharge of pin-point floc normally associated with high SRT systems) From the aerobic compartment the mixture of microbial cells and water enters the sludge filter at the bottom and, as it rises, upward velocity decreases until the flocs of cells become stationary and thus form a filtering media. High degree of filtration efficiency is achieved as even particles with settling velocities too low to be removed by settling alone are filtered out. As the flocs become large and heavy by impact agglomeration, they descend to the bottom of the sludge filter and subsequently are recycled back into the anoxic zone.
Main advantage of the combined USBF technology is possible higher hydraulic load into secondary clarifier, comparing to e. g. radial clarifiers, this will reduce volume of secondary clarifier. For the same reason, it is possible to operate USBF reactor at higher mixed liquor suspended solids (MLSS) concentrations compared to conventional settlement separation systems. The disadvantage of this technology is unstability to a sudden change of wastewater flow and quite complicated regulation process.
RBC technology (rotating biological contactors)
Rotating Biological Contactors are an efficient fixed-film wastewater technology well suited for secondary and/or advanced biological treatment. The RBC process consists of a large disc with radial and concentric passages slowly rotating in a concrete tank. During the rotation, 40 percent of the media surface area is in the wastewater. The rotation and subsequent exposure to oxygen allows organisms to multiply and form a thin layer of biomass. This large, active population causes the biological degradation of organic pollutants. Excess biomass shears off at a steady rate and is carried through the system for removal in a clarifier. For smaller, prefabricated WWTP (for example for hotels, or small industry) RBC can be combined with MBR instead of secondary clarifier in order to make unit very compact.
The main advantage of RBC technology is very low operational costs, comparing to other treatment technologies, due to absence of aeration system (aeration takes up to 70% of overall WWTP electric energy consumption). The main disadvantage – high installation costs and size limits (usually only for villages and very small towns).
Reed bed (field) WWTP : wastewater treatment while plant’s.:
- roots uses organics, nitrogen and phosphorus for their grown as fertilizer.
- Water trickling through the reed bed is cleaned by microorganisms living on the root system and in the litter. These organisms utilize the sewage for growth nutrients, resulting in a clean effluent. The process is very similar to aerobic conventional sewage treatment, as the same organisms are used, except that conventional treatment systems require artificial aeration.
- Plants releases oxygen during photosyntesis and ensures water aeration
The main advantage of reed bed technology is very lowest operational costs, because no electricity is required during operation. Also the plants can absorb and accumulate heavy metals in the roots, what make this technology good for industrial applications (for.example highway, or gas station surface water treatment).
The main disadvantage – installation requires big site – usually this technology available only for villages and very small towns up to 4000 PE.
Starting-up and adjustment of wastewater treatment systems
The personnel of the company renders consultations and carries out starting-up as well as adjustment of wastewater treatment plants and helps solving problems during the course of operation of treatment plant.
Plant operation and Equipment maintenance
Starting from the early 2000-th, when our country start to gain EU cohesion funding we realized the problem, that after completion of the WWTP or WTP project, difficulties arise in the operation and service of installed equipment. The main purpose of that – qualified and skilled Employer’s personnel absence. Especially this is huge problem for mid and small size WWTP’s. This may lead to failure of new high technology equipment.
Another problem is low qualification and experience of Employer’s water engineers-technologist. And again, this is huge problem for mid and small size WWTP’s. This may lead to failure overall treatment process, even when equipment is functioning well.
Usually plants are operated by public utility. Due to lower salaries, than in private sector public water utilities are not able to hire high skill engineers and workers, invest in their education and training. There is also a problem of specialist work productivity and lower effective management. All these factors leads to the situation, when the transfer of operation and maintenance services to a private company will decrease overall costs and increase service quality dramatically.
For these reasons, our company successfully have offered our Customers Plant operation and equipment maintenance services. Since 2005 our company our company has been providing operation and maintenance services for Vilnius, Švenčionys, Šalčininkai and other WWTP‘s.
Installation of technologic equipment, stainless and structural steel technological pipelines, structures and elements
We strive to provide the highest level of quality in all stages of the construction process. Comparing with other competitors-engineering companies, we make technologic installation work by our own installers. All our installers are very high skilled and certified. All our welders has welder approval test certificates. Most of installers works in Arginta for 10 and more years.
Having skilled staff we make installations of various stainless and structural steel technological pipelines, and structures for water and waste water treatment plants, pumping stations and etc. Also we install different type of technological equipment, as: screens, grit chambers, grit separators dewatering equipment and etc.) or their individual elements, such as scrapers of clarifier’s bridges, aeration system, pump and mixers lifting systems and etc.).