Which type of PVC sheet do I need for my application?

What is PVC (PolyVinyl Chloride)?

Polyvinyl Chloride (PVC or Vinyl) is an economical and versatile thermoplastic polymer widely used in building and construction industry to produce door and window profiles, pipes (drinking and wastewater), wire and cable insulation, medical devices, etc. It is the world’s third largest thermoplastic material by volume after polyethylene and polypropylene.

It is a white, brittle solid material available in powder form or granules. Due to its versatile properties, such as lightweight, durable, low cost and easy processability, PVC sheet is now replacing traditional building materials like wood, metal, concrete, rubber, ceramics, etc. in several applications.

Basic Forms of PVC(including PVC rod)
Polyvinyl Chloride is widely available in two broad categories: Flexible and Rigid. But, there are more types like CPVC, PVC-O and PVC-M.

Plasticized or Flexible PVC (Density: 1.1-1.35 g/cm3): Flexible PVC is formed by the addition of compatible plasticizers to PVC which lower the crystallinity. These plasticizers act like lubricants resulting in a much clearer and flexible plastic. This type of PVC is sometimes called as PVC-P.

Unplasticized or Rigid PVC (Density: 1.3-1.45 g/cm3): It is a stiff and cost-effective plastic with high resistance to impact, water, weather, chemicals and corrosive environments. This type of PVC is also known as UPVC, PVC-U or uPVC.

Chlorinated Polyvinyl Chloride or perchlorovinyl: It is prepared by chlorination of PVC resin. High chlorine content imparts high durability, chemical stability and flame retardancy. CPVC can withstand a wider range of temperatures.

Molecular Oriented PVC or PVC-O: It is formed by reorganizing the amorphous structure of PVC-U into a layered structured. Bi-axially oriented PVC has enhanced physical characteristics (stiffness, fatigue resistance, lightweight, etc.).

Modified PVC or PVC-M: It is an alloy of PVC formed by addition of modifying agents, resulting in enhanced toughness and impact properties.

Polyvinyl Chloride (PVC) is one of the most widely used polymers in the world. Due to its versatile nature, PVC, or other plastic rod, is used extensively across a broad range of industrial, technical and everyday applications including widespread use in building, transport, packaging, electrical/electronic and healthcare applications.

PVC, including soft PVC sheet roll, is a very durable and long lasting material which can be used in a variety of applications, either rigid or flexible, white or black and a wide range of colours in between.

The essential raw materials for PVC are derived from salt and oil. The electrolysis of salt water produces chlorine, which is combined with ethylene (obtained from oil) to form vinyl chloride monomer (VCM). Molecules of VCM are polymerised to form PVC resin, to which appropriate additives are incorporated to make a customised PVC compound .

The PVC production process consists of 5 steps:

The extraction of salt and hydrocarbon resources
The production of ethylene and chlorine from these resources
The combination of chlorine and ethylene to make the vinyl chloride monomer (VCM)
The polymerisation of VCM to make poly-vinyl-chloride (PVC)
The blending of PVC polymer with other materials to produce different formulations providing a wide range of physical properties.

PVC sheet, PE sheet and PP sheet have excellent corrosion resistance and weather resistance. The working temp is 33 deg F to 160 deg F. and the forming temperatures of 245 deg F. It is good electrical and thermal insulator and has a self-extinguishing per UL Test 94. PVC applications are almost unlimited. It’s the most widely used member of the vinyl family. It is excellent when used for corrosion-resistant tanks, ducts, fume hoods, and pipe. Ideal for self-supporting tanks, fabricated parts, tank linings, and spacers. It is not UV stabilized and has a tolerance of +or 10%. Not FDA approved materials. Colors available: Gray PVC Type 1 Sheet, White PVC, Clear PVC.

Desuperheater Application Best Practices

Desuperheater Application Best Practices
An ever-increasing need for steam at specific temperatures and pressures exists in many modern plants. Fortunately, significant improvements have been made to increase operational thermal efficiency and heat rates by the precise, coordinated control of the temperature, pressure and quality of this steam. But, much of the steam produced in power and process plants today is not at the required conditions for each application, so conditioning is required, often by a desuperheater system.
The sizing, selection, application, installation and maintenance of the proper desuperheating and steam-conditioning equipment, including control valves, is therefore critical to optimum performance. This article will discuss superheaters and associated control valves in detail, but first I will look at common applications and issues in affected industries.
Power Industry
Competing in the modern power market requires a heavy emphasis on the ability to utilize multiple operating strategies. Increased cyclical operation, daily start-stop and faster ramp rates are required to ensure full-load operation, particularly at daily peak hours, and to maximize profit and plant availability. Changes resulting from environmental regulations and economics also are combining to alter the face of power production.
At the same time, these changes are affecting the operation of existing power plants and the design of future plants. Advanced plant designs include requirements for increased operating temperatures and pressures along with stringent noise limitations in urban areas. Steam is used throughout power plants in many ways, from driving to turbines to feedwater heaters.
Hydrocarbon and Petrochemical Industries
Hydrocarbon and petrochemical industries rely on the efficient conversion of low cost feedstock to high profit products. Hydrocrackers, furnaces, distillation columns, reactors and other process units must be designed to meet a range of conditions to accommodate various modes of plant operation. Temperature is a critical factor that must be taken into consideration during the design of each process unit, and it must be controlled precisely to optimize each operation.
Temperature is controlled in many ways in these plants. The most common method is through the use of heat exchangers and process steam. Process steam must be conditioned to a point near saturation before it is transformed into a medium that is more efficient for heat transfer. The proper selection of equipment will ensure optimum plant availability, reliability and profitability.
Other process industries such as mining, pulp and paper, life sciences and food and beverage experience reliability issues caused by steam-conditioning challenges. These industries also use steam for motive force and heat transfer.
Desuperheater Basics
A schematic of a typical desuperheating system is shown in figure 1. A typical system consists of four main components:
Control valve.
Temperature transmitters.
Spray-water strainer.
When specifying a desuperheater, it is advisable to consult with the manufacturer because most desuperheater suppliers have multiple models from which to choose. Critical parameters (figure 2) include:
Spray-water temperature.
Spray-water pressure.
Initial steam superheat temperature.
Final steam superheat temperature.
Minimum steam velocity.
Maximum steam velocity.
Pipeline size.
Downstream straight-pipe length.
Steam-pipe liner.
While each components affects operation, a note on orientation is warranted. Orientation can affect the speed of vaporization. Horizontal installations are most common, but vertical flow-up installations perform slightly better because of the positive effect of gravity. Vertical flow-down pipes perform less efficiently because of the negative effect of gravity, which reduces residence time.
Details of the actual control of a desuperheater are beyond the scope of this article; however, suffice it to say that pressure, temperature and flow sensors feed data to a control system that adjusts the spray-water control valve to deal with changing conditions.
Control Valve Considerations
When a desuperheating system is purchased, often each component will be specified and purchased separately. In other words, the desuperheater will be purchased from one vendor, the control valve from another and so on. Unless the process plant has an extensive expertise in the design of superheating systems — not often the case — this approach is problematic due to the complexity of these systems.
The reasons are:
There is generally a turndown specification for the system that needs to be met. The control valve has a turndown ratio, the desuperheater has a turndown ratio and the combination of the two has a completely different turndown ratio. Therefore, sizing and selection are critical to ensuring system performance is met.
Different desuperheater designs will have different differential pressure (dP) requirements across the nozzles. The control valve differential pressure must be coordinated with the differential pressure across the desuperheater nozzles to ensure system performance is met.
If there is a high differential pressure across the control valve — when a high pressure source is used to spray water into a low pressure steam line, for instance — cavitation can occur in the valve. The proper anti-cavitation trim must be installed in the control valve to suppress cavitation. If not, it is possible to have a cavitating pressure drop across the desuperheater nozzle, with catastrophic damage resulting, and potentially sending eroded desuperheater components into downstream equipment.
A desuperheater nozzle has a specific flow coefficient (Cv). A control valve also has a range of flow coefficients based on its design. The flow coefficient for the valve and desuperheater must be matched so that overall system flow coefficient is optimized.
It presents results in the thermal energy recovery system (TERS) investigation, and the possibility of introducing them to production vehicles as subsystems. This prospective new technology should reduce dependence on fossil fuels. One of the TERS systems’ research objectives is to create a sustainable, electrical power source, suitable for the energy to be stored and later used in the electrical vehicle driving mode (EV)1. It will also lower the impact on the environment by reducing fuel consumption through the application of automotive thermoelectric generators (ATEG) instead of classical alternators that convert mechanical energy to electrical.
Pressure reducer and desuperheater system (PRDS) is used for Steam Conditioning Services for reduction of pressure and temperature of steam. Suitably designed pressure reducing valve installed on superheated steam line, reduces steam pressure to desired operating pressure. The steam temperature is reduced close to saturation by injecting water into high velocity steam by controlled water flow through water control valve and often injected into the steam where steam velocity and turbulence are at their highest, which gives quick and efficient cooling. The purpose of this project is to optimize the Pressure reducing and desuperheating system to overcome the current losses such as valve leakage, gland leakage and header leakage.

Types of wear-resistant ceramic pipe and its application in industrial productio

Types of wear-resistant ceramic pipe and its application in industrial production
Including abrasion resistant ceramic pipe elbow, straight pipe , structural tee, head size, radius sections , adjustable pipe , mainly used for the air force , pumping slurry pipeline and other materials . Because the transmission medium with high hardness, flow speed , flow characteristics, can effectively reduce the transmission medium to the wall to produce long-lasting impact, abrasion , corrosion fatigue causes the pipe was gradually worn out speed.

1 , the definition of wear-resistant ceramic pipe
Depending on the working conditions of wear on the wear-resistant ceramic pipe lining materials have different choices. Resistant ceramic lined pipe ( lining of aluminum oxide , silicon carbide , zirconia, silicon nitride , sialon , aluminum nitride, boron nitride , etc. ) ; resistant alloy tube ; hexsteel wearable pipe fittings ; rubber resistant steel grinding tube ; wear-resistant plastic tube ; wear-resistant cast stone pipe ; wearable self-propagating composite pipe ; rare earth alloy wear-resistant pipe.

2 , the main application of wear-resistant ceramic pipe
In addition to used in coal-fired power plants wear elbow ash , slag pipe , powder , powder tube back , desulfurization pipes , but also widely used in the following industries:
Mining : Coal industry CWS , washing mud , mine backfill , mine coal powder ;
Metal mines : concentrate and tailings transport wear elbow ;
Metallurgy : Steel mill blast of pulverized coal injection , slag and other transmission pipelines ; CAO, zinc Bei sands pipeline , transporting steel alloys, refining , etc. Preferably wear elbow ;
Cement : raw slurry wet rotary kiln production line conveyor , coal transportation, upgrading cutting machine , pneumatic conveying finished unloading cement , concrete wear elbow .
Chemical : pulverized coal pipeline , transporting raw materials such as silica fume wear elbow .

The main application sectors 3 , wear-resistant ceramic pipe
In addition to used in coal-fired power plants wear elbow ash , slag pipe , powder , powder tube back , desulfurization pipes , but also widely used in the following industries:
Mining : Coal industry CWS , washing mud , mine backfill , mine coal powder ;
Metal mines : concentrate and tailings transport wear elbow ;
Metallurgy : Steel mill blast of pulverized coal injection , slag and other transmission pipelines ; CAO, zinc Bei sands pipeline , transporting steel alloys, refining , etc. Preferably wear elbow ;
Cement : raw slurry wet rotary kiln production line conveyor , coal transportation, upgrading cutting machine , pneumatic conveying finished unloading cement , concrete wear elbow .
Chemical : pulverized coal pipeline , transporting raw materials such as silica fume wear elbow .

4, the detailed use of wear-resistant ceramic pipe
Transport has been around electricity, metallurgy, coal , petroleum, chemicals, building materials , machinery and other industries, and high-speed developing. When the wear-resistant ceramic grinding large pipeline materials (such as ash , coal , ore concentrates , tailings, cement, etc. ) , there is an abrasion resistant ceramic pipe faster , especially wear elbow faster. When the pipeline in the wear-resistant ceramic having a strong corrosive gas , liquid or solid , there is a problem of corrosion and wear-resistant ceramic pipe is quickly destroyed . When the pipeline resistant ceramic materials with higher temperatures , there is a heat-resistant steel prices are very expensive problem. After resistant ceramic pipe market, these problems are solved. Wear resistant ceramic pipe is widely used in mine backfill serious , transporting ore concentrate and tailings , coal-fired power plant feed powder , slag , ash and other wear-resistant ceramic pipes are also very suitable . Resistant ceramic pipes are transported strong corrosive acid, alkali , salt and abrasive both solid , wear-resistant ceramic pipe ideal liquid delivery . In the high-temperature corrosion resistant ceramic pipe , high temperature or high-temperature ablation wear occasions using very safe and reliable.

5 , wear-resistant ceramic pipe production technology
Resistant ceramic pipes are using self- propagating high temperature synthesis – centrifugation manufacture. After that is placed inside the centrifuge tube seamless steel mold , joined in the steel and aluminum oxide powder mixture , the mixture called thermite in chemistry , centrifuge tube mold rotation reaches a certain speed , through a Mars ignite thermite , thermite now own , the combustion wave spread rapidly , following violent chemical reaction occurs when the spread.
Chapter One – What are Alumina Ceramics?
Alumina Ceramic Liner is an industrial ceramic that has high hardness, is long wearing, and can only be formed by diamond grinding. It is manufactured from bauxite and can be shaped using injection molding, die pressing, isostatic pressing, slip casting, and extrusion.
Products made from alumina, some of which are shown in the image below, are wear, chemical, erosion, corrosion, and high temperature resistant and bioinert, making them perfect for medical implants.
Alumina ceramics are a technical ceramic due to their properties and price to performance ratio. The classification of alumina ceramics is based on their alumina content, which can vary from 70% to 99.9%. The higher the purity of alumina, the stronger is its wear and corrosion resistance.
Chapter Two – Properties of Alumina Ceramics
Alumina ceramics are made from a white granular material that is similar to table salt or a very fine silky dense powder. The three general types of alumina are hydrated, calcined, and tabular. Each type has a variety of grades.
The types of alumina vary according to the amount of soda (Na2O), iron (Fe2O3) and silica (SiO2) they contain as well as their chemical purity and the properties of the powder used in the production process.
To produce calcined alumina, aluminum oxide is heated to 1050° C or 1900° F. The super heating removes all chemicals and water creating a very pure, 99.99% pure, with a 9 on the Mohs hardness scale, which is just below a diamond’s Mohs rating of 10.
Alumina hydrate, or alumina hydroxide, is used as a glaze because of its ability to stay in suspension in glaze slurries and adhesive qualities.
Tabular alumina is produced by heating aluminum oxide to 1650° C or 3000° F. It has a high heat capacity, excellent thermal temperature, strength, and volume stability. It is formed from sintering balls of calcined alumina, which are crushed to form a powder. Tabular alumina has high refractory properties, mechanical strength, wear resistance, chemical purity, dielectric properties, and corrosion resistance in acids and alkaline.
Properties of Alumina
High Temperature Ability
Alumina is used in oxidizing and reducing atmospheres up to 1650°C or 2900°F as well as vacuum environments of 2000°C or 3600°F. At 1000° C, it keeps 50% of the tensile strength it has at room temperature. While metals are weakened by high temperatures, alumina ceramics retain their strength when they return to normal temperatures and are unchanged.
Abrasion Resistant
Abrasion wears down a material by rubbing it away by friction. The resistance to abrasion means a material will maintain its original structure even after mechanical wear. Alumina ceramics are high in abrasion resistance due its hardness.
Chemical Resistance
Alumina is resistant to acids and alkalis at high temperatures because it is inert, not chemically reactive, which makes it resistant to the effects of chemicals such as solvents and salt solutions.
The density of a material is its mass divided by its volume, which is read as grams per cubic centimeter (g/cm3) where grams is mass and cubic centimeters is volume. As the volume increases, the density of the material increases. Alumina ceramics are made from fine particles that do not allow for voids in the material. The fewer voids means the material has high volume and density. The density of alumina ceramics varies according to the temperature. At 25° C, its density is 3.965 g/m3 at standard atmospheric pressure.
The mechanical properties of a material is determined by its strength, which is the amount of stress and strain it can endure. Alumina has superior strength and hardness that improves with the purity of the different grades.
Alumina has high resistivity and reduces thermal shock. The increased purity of alumina increases its resistivity.
Alumina ceramics make a perfect insulation material because of its dielectric equality, the inability of an electric current to pass through them.
Hardness tells the ability of a material to be able to endure mechanical wear and abrasion. Alumina ceramics are harder than steel and tungsten carbide tools. They are harder than sapphire and are excellent for mill linings and bearings. According to Rockwell hardness, alumina ceramics are at HRA80-90, second only to diamonds and above stainless steel.

ZTA ceramic liner is zirconia toughenedalumina ceramic liner ,belonging to inorganic non-metallic materials, is a good wear-resistant materials. Zirconia toughening alumina ceramic is added pure 99 Zr02 zirconia, the particles form ZrO2 toughened alumina ceramic. Alumina toughness can be significantly improved when zirconia is added as appropriate. It can be said that the toughening of alumina ceramics is the toughening method most used at present, and about 20% zirconia (ZrO2) is added to toughen the alumina.
ZTA toughening effect mainly comes from the following mechanism:
(1) to make the aluminum oxide grain refinement.
(2) Zirconia phase change toughening.
(3). Micro-crack toughening.
(4). Crack steering and bifurcation. Zirconia toughened alumina mechanical properties: ZTA
(zirconia toughened alumina) ceramic density > 4.1, Rockwell hardness > 90, Vickers hardness >
1300, fracture toughness 6.0, flexural strength 480MPa, compressive strength 3600MPa, ZTA toughening alumina ceramic liner is added on the basis of alumina zirconia ceramic ingredients, abrasion resistance and toughness between the alumina ceramic and zirconia ceramics, zirconia ceramics because the higher prices, the user once The larger the amount investment, the largest number of manufacturers are mostly European and American companies and BHP Billion and other groups.
What is Concrete Pump Pipe?
Concrete pump pipeline is used with concrete pumps to ensure that the concrete is delivered correctly and safely to where it needs to be. It’s an essential part of truck-mounted concrete pumps, trailer pumps, or placing booms. The concrete pump pipe is the most wearing component on a concrete pump as it has the biggest contact and the most friction with the concrete. The durability of pipes is one of the major factors to the pumping efficiency.

Application of Moving Bed Biofilm Reactor (MBBR)

Application of Moving Bed Biofilm Reactor (MBBR)
This review paper present the MBBR and IFAS technology for urban river water purification including both conventional methods and new emerging technologies. The aim of this paper is to present the MBBR and IFAS technology as an alternative and successful method for treating different kinds of effluents under different condition. There are still current treatment technologies being researched and the outcomes maybe available in a while. The review also includes many relevant researches carried out at the laboratory and pilot scales. This review covers the important processes on MBBR and IFAS basic treatment process, affecting of carrier type and influent types. However, the research concluded so far are compiled herein and reported for the first time to acquire a better perspective and insight on the subject with a view of meeting the news approach. The research concluded so far are compiled herein and reported for the first time to acquire a better perspective and insight on the subject with a view of meeting the news approach. To this end, the most feasible technology could be the combination of advanced biological process (bioreactor systems) including MBBR and IFAS system.
The BioCellTM media are suitable for a moving bed biofilm reactor (MBBR) system to provide a self-shedding, self-regulating growth biofilm treatment process. The media can be used for MBBR treatment alone or as an integrated fixed membrane activated sludge (IFAS) process to enhance the effective capacity of existing activated sludge systems.
The BioCellTM medium used in MBBR media or IFAs is a continuous motion caused by air injection and agitator. Specific density of the media can be adjusted between 0.95-1.05 g/cm3 according to customer requirements. However, it should be considered that with the formation of biofilm on the surface of the medium, the actual density of the carrying media will increase.
The main characteristic of Moving Bed Biological Reactor (MBBR) configurations is that there is no sludge recycle from a secondary clarifier. MBBR is essentially a simple, once-through process, where all of the biological activity takes place on the biomass carriers. MBBR is usually followed by a solids separation system such as a secondary clarifier or DAF, in order to separate bio-solids produced in the process from the final effluent. The main advantage of MBBR is robust and simple reduction of soluble pollutants (soluble BOD or COD, NH4 +, etc.), with minimal process complexity, utilizing a significantly smaller footprint when compared to conventional aerobic treatment methods. MBBR is typically used for either high load industrial applications or for robust simple-to-operate municipal facilities.
The Integrated Fixed-film Activated Sludge (IFAS) process combines the advantages of conventional activated sludge with those of biofilm systems by combining the two technologies in a single reactor. Typically, an IFAS configuration will be similar to an activated sludge plant (utilizing all of the different process configurations such as MLE, UCT, Bardenpho, etc.), with biomass carriers introduced into carefully selected zones within the activated sludge process. This allows two distinct biological populations to  act  synergistically, with the MLSS degrading most of the organic load (BOD), and the biofilm creating a strongly nitrifying population for oxidation of the nitrogenous load (NH4+). IFAS is typically used to upgrade existing plants in order to enable extensive Nitrogen removal, or in designing new plants with significantly smaller footprints for extensive BOD and Nitrogen removal.
 The diffuser is the special design for MBBR bio carrier media aeration system. The coarse-bubble design is employed to mix the suspended media evenly throughout the reactor  while  providing  the  mixing energy required to slough old biofilm from the internal surface area of the media and maintain the dissolved oxygen required  to  support the biological treatment process.

Coarse bubble diffuser is made of stainless steel (SUS304 or SUS316L is optional).The  coarse bubble diffuser provides maximum aeration and mixing efficiency.The standard length of diffuser is 600 mm. A 600mm long diffuser can achieve a 1250mm air release circumference.It has a service life of over 15 years. 
The dissolved air flotation(DAF) system is designed to remove suspended solids(TSS), biochemical oxygen demand (BOD5), and oils and greases (O&G) from wastewater. Contaminants are removed by using a dissolved aqueous solution of water produced by injecting air into the recirculating stream of clear DAF effluent under pressure. The recycle stream is then mixed with the upcoming wasterwater in the internal contact chamber. Air bubbles and contaminants rise to the surface and form a floating bed material that is removed by a surface skimmer into the internal hopper for further processing.
The initial section of dewatering drum is the Thickening Zone, where the solid-liquid separating process takes place and where the filtrate will also be discharged. The pitch of the screw and the gaps between the rings decrease at the end of dewatering drum, hence increasing its internal pressure. At the end, the End Plate further increases the pressure, so as to discharge dry sludge cake.
Albe Advance Group is the leading industrial water treatment solution provider in Malaysia with decades of experience in providing quality water treatment solutions. We prioritise in providing our clients with a one-stop water treatment centre for industrial water treatment project and services. Having doubts on industrial water treatment qualities? Contact us and let our skilled professionals provide you with a consultation in water treatment program.
In traditional activated sludge plants, biomass form flocks are kept suspended in wastewater and then separated from treated water in a settler; most biomass is re-circulated to the biological tanks, the excess is extracted and sent to sludge treatment.
Luigi Falletti, University of Padova
This technique is the most widespread and well known in the world to treat biodegradable municipal and industrial wastewater (including paper mill wastewater); but it has also disadvantages: it requires large tanks, and pollutant removal efficiency is strongly affected by sludge settleability.
In moving bed biofilm reactors (MBBR) biomass grows as biofilm on plastic carriers that move freely into wastewater; tanks are similar to activated sludge reactors, and they have screens or sieves to avoid carriers’ loss; aerated reactors are mixed by aeration itself, while anoxic and anaerobic reactors are mixed mechanically. MBBR can be classified into two categories:

  1. pure biofilm reactors: biomass grows only on carriers without suspended sludge and without sludge recirculation;
  2. hybrid reactors: in the same tank biomass grows both as biofilm on carriers and as suspended sludge; part of sludge is re-circulated.

MBBR have several advantages if compared to traditional activated sludge tanks and to fixed biofilm reactors (trickling filters, submerged biofilters):
-biofilm has high specific activity, therefore high pollutant removal efficiencies can be achieved with smaller tanks than the ones required by activated sludge;
-in plants with a series of MBBR a specialized biomass grows in each tank;
–risk of clogging with MBBR is much lower than with fixed biofilm reactors, no backwashing is required since biofilm in excess is detached from carriers by reactor turbulence itself, and can be separated from treated water by settling or flotation;
-this technology is very flexible in plant conduction: in pure biofilm reactors, the filling degree can be varied according to process requirements, in hybrid reactors also sludge recirculation rate can be varied.
Several kinds of carriers are used in MBBR: they can be classified according to material, shape, porosity, dimensions, specific surface. Among these characteristics, specific surface is particularly important: it represents the surface which is available for biofilm growth pr. cubic meter carriers. For each kind of carrier, part of specific surface is protected and the remaining part is external; biofilm grows almost only on protected surface, because external surface is exposed to collisions among carriers and against reactor walls; so the effective specific surface is only a protected one. First biofilm growth on carriers requires some weeks; bacteria produce surfactant substances, so some scum can be observed during the first days in plant starting [1, 2, 3, 4].
Carriers can be introduced in MBBR in variable amounts: filling degree is the ratio between the carriers’ apparent volume and the tank volume, and it can vary from zero to a maximum value that depends on the carriers’ characteristics. With higher filling degree, total biofilm surface and pollutant removal efficiency increase, but higher mixing energy is required. The most widespread carriers are made of polyethylene or polypropylene, their density is about 0.95, and usual filling degrees’ range is 30–60%; the characteristics of some kinds of carriers produced by AnoxKaldnesTM Company are listed in table 1.
Possible configurations
Mbbr sewage treatment can be applied for wastewater treatment in several plant configurations:
1. pure MBBR biofilm before an activated sludge plant: this solution is common for concentrated wastewater treatment;
2.upgrading of overloaded activated sludge plants by conversion into hybrid MBBR;
3.tertiary biological treatment by pure biofilm MBBR after an activated sludge plant;
4.complete biological treatment by series of MBBR: pre-denitrification, oxidation, nitrification, post-denitrification.
MBBR have been and are applied to treat municipal wastewater [5, 6, 7, 8, 9] and industrial wastewater including paper mills [10, 11, 12], winery [13] and dairy [14]. This paper deals with the results of some European full-scale plants with MBBR for paper mill wastewater treatment.
Industry nr. 1 produces about 18.000 m3d-1 wastewater with 2.500–3.500 mg/L COD. The wastewater treatment plant (picture 1) is made of a coarse screen, a primary settler, a fine screen, a cooling system, dosage of nutrients (nitrogen and phosphorus salts), a biological section and a final clarifloculation. The biological section has a first aerated pure biofilm MBBR filter media with 2.500 m3 volume filled with 40% NatrixTM – O carriers, an activated sludge oxidation tank with 7.500 m3 volume and sludge concentration 4-6 kgSSTm-3, and a secondary settler. The plant must remove at least 90% of COD, 99% of BOD5; maximum pollutant concentrations in final effluent are: TSS < 50 mg/L, tot-N < 4.7 mg/L, P < 0.3 mg/L.
On average basis, the plant has treated an effective organic load of 59.000 kgCODd-1, the first MBBR has removed 51% of COD and the following activated sludge oxidation tank has removed 75% of remaining COD; the whole plant has removed 90% COD and has always respected emission limits.
Industry nr. 2 produces about 18.000 m3d-1 wastewater with 2.000-2.500 mg/L COD. The wastewater treatment plant (picture 2) is made of a cooling system, dosage of nutrients (nitrogen and phosphorus salts), pH correction and a biological section. The biological section is made of two serial aerated pure biofilm MBBR with 1.900 m3 volume each filled with 20% NatrixTM – O carriers, an activated sludge oxidation tank with 10.000 m3 volume and sludge concentration 2-5 kgSSTm-3, and a final settler. The plant must remove at least 70% COD, 50% total nitrogen and 50% total phosphorus; moreover, maximum TSS concentration in final effluent is 30 mg/L.
On average basis, the plant has treated an effective organic load of 38.000 kgCODd-1, the two MBBR have removed 35% COD, the whole plant has removed 70% COD and has always respected emission limits.
Industry nr. 3 produces 2.800 m3d-1 wastewater 800-1.300 mg/L COD. The wastewater treatment plant (picture 3) is made of an equalization tank with 600 m3 volume, a primary settler (with fiber recovery), dosage of nutrients (nitrogen and phosphorus salts) and a biological section. The biological section is made of a pure biofilm aerated MBBR with 500 m3 volume filled with 68% AnoxKaldnesTM – K1 carriers, and a secondary settler with polyelectrolyte dosage. Maximum pollutant concentrations in final effluent are: TSS < 35 mg/L, COD < 160 mg/L, BOD5< 40 mg/L.
On average basis, the biological section has treated an effective organic load of 2.660 kgCODd-1, and has removed 90% COD; the final effluent has always respected emission limits.

Application Password is not enable by default?

So I have this site running under ssl (on siteground).

The site is new, the instalation has no more than 2 weeks.

I have a working desktop app to connect to my sites, using jwt tokens, but the plugins for this token are old and has not being tested with newer WP versions. So to keep everything up to date, I want to change to this kind of auth.

But when I try my site, using get over the rest-api, I don´t get the authentication key according to this.

So I think that app passwords are not enable by default.

If that is the case, according to that page, I have to add:

add_filter( 'wp_is_application_passwords_available', '__return_true' ); 

somewhere, but I don´t know where to add it.

Or is this something else I have to be cheking?

Best Database to be shipped with my application?

I have a .net core application using a database. I need to create an installer using nsis where I will be packaging my application along with a database , so that the client can easily install my application and database along with all its dependencies using a simple wizard.

I want a suggestion regarding the database.


  1. Easy to install, it must be lite weight , as much less dependencies as possible, have zip binaries to install, and error free during installation.
  2. Database should be able to handle large no of records and remote connections.

what I have tried:

  • MSSQL Server: no binary file option, has large size and has so many dependencies.
  • SQLite: it’s a file based, no remote connections possible
  • PostgreSQL: it was a perfect choice, but it has many installation issues and bugs, even the official installer is failed to install on some of the machines.

Core Web Vitals (CLS and LCP) errors for a client-rendered Single Page Application (built with React + Firebase)

I have a SPA (single page website) build with React + Firebase and I’ve been getting these Core Web Vitals errors (see images below).

My website is loading normally both on Desktop and Mobile. And I think it’s rendering in a very reasonable time. At least I think it’s way faster than most websites I visit, even though it’s client side rendered.

I’m guessing these errors on Core Web Vitals are being triggered because there’s a Spinner that runs while the app is loading its data.

For example: that report is probably measuring the Spinner vs Loaded content as layout shift. Because I can guarantee that my app has ZERO layout shift. Once the Spinner is gone and you see content on your screen, the app is 100% ready for you to browse and interact with.

Maybe to get rid of those errors I would have to do SSR + hydration, which I really don’t want to, because it’s a dynamic website and I would have to either remove caching completely, or to risk a content (state vs fresh) flickering on the screen once it’s fully hydrated.

Should I care about these results? Is anybody that also manages a SPA also getting these kind of errors? Is there a way to fix this?

Found some related articles:

  • https://www.moovweb.com/post/google-penalizes-pwas-spas
  • https://www.enterspeed.com/core-web-vitals-can-affect-how-google-ranks-your-spa-website/

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How to Remove or Deactivate “Application Passwords” in WordPress

With version 5.6, I got this new weird "Application Passwords" under all user profiles. No idea what it is and what it does except for what it says — and I want it gone.

If anyone knows how to remove this using __return_false with a filter or something, please tell me. I’ve googled and looked at the developers handbook and so far; nothing.

See image for more information.Application Passwords

Capturing SQL calls sent to a remote server from application

First of all, I’m not well versed in SQL anything at all. Closest I’ve ever needed to get was storing and retrieving data from a local SQLite db.

In essence I think I have a simple problem but it’s hard to orient yourself when everything is new.

My main tool at work is an ERP software, which is basically a front end to an SQL db.

Problem I have with it is that it’s very clumsy and doesn’t allow automation of even the most basic tasks.

What I want to do, is bypass the front-end completely and interact directly with the db to automate most of my tasks with python.

I can connect to the database just fine from python environment, but the schema is gigantic, there’s no way I’ll be able to find whatever it is I might be looking for.

So I need to capture the call front-end sends when I click a button (telling it to display specific set of data) to use that call as a guide.

Basically, how can I, an SQL noob, capture calls that a desktop application sends to a remote server?

Edit 1: My job is mostly analytical, so all of my automation will be for retrieval, analysis and visualization. I’m not very likely to mess anything up.

Edit 2: Tried running a Profiler and got the message:

"In order to run a trace against SQL Server you must be a member of sysadmin fixed server role or have the ALTER TRACE permission."

I’m not a sysadmin, don’t have an alter trace permission and reeeally don’t feel like asking for it 😀