The removal of phosphorus (P) from domestic wastewater is primarily to reduce the potential for eutrophication in receiving waters, and is mandated and common in many countries.
Does your wastewater treatment plant perform enough phosphorus removal?
Dec 21, 2017 · Phosphorus is a nutrient that increases plant growth; it’s great for food crops, but it’s not great for aquatic systems because it enhances the growth of plants over the growth of other wildlife—eutrophication. One of the most significant consequences of eutrophication is the growth of algal blooms ( cyanobacteria ), some of which produce ...
What chemicals are used to remove phosphorus from wastewater?
Phosphorous removal from wastewater Controlling phosphorous discharged from municipal and industrial wastewater treatment plants is a key factor in preventing eutrophication of surface waters. Phosphorous is one of the major nutrients contributing in the increased eutrophication of lakes and natural waters.
What is the source of phosphorus in wastewater?
Sep 22, 2014 · Introduction. The removal of nitrogen and phosphorus from wastewater has become an emerging worldwide concern because these compounds cause eutrophication in natural water. Moreover, nitrate is a risk to human health, especially as a possible cause of infant methaemoglobinaemia [ 1 ].
How do you reduce the concentration of phosphorus in a filter?
This is not only much more efficient, requiring far less chemical to achieve even the lowest phosphorus limits, but provides sweeping benefits that include the following: Less sludge volume Denser, easier to dewater sludge, requiring less polymer Better settling and cleaner clarifiers Lower sludge disposal costs
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Jan 01, 1988 · A high influent organic concentration can reduce the efficiency of chemical phosphorus removal, and primary treatment could be used to reduce the BOD and suspended solids concentration (Mertsch et al., 1985). Rapid efficient mixing plays an important role in phosphorus precipitation (Karlsson, 1985).
Why is phosphorus bad in wastewater?
High levels of phosphates in aquatic environments can fuel algal growth, resulting in algal blooms that can potentially lead to eutrophication as the thick algal mats block out sunlight causing the algal cells to die off.Jul 20, 2018
Why do the phosphorus need to be removed from sewage before it can be discharged on the surface water?
Why is it important to remove phosphorus and nitrogen from the treated wastewater before releasing it into lakes streams rivers?
How do wastewater treatment plant removal phosphorus?
What is the effect of phosphorus in water?
Can phosphorus be filtered out of water?
Why is phosphorus bad for the environment?
What are the consequences of high concentration of phosphorus in the water?
Why is it important to remove nutrients from wastewater?
How does chemical phosphorus removal work?
How are nitrogen and phosphorus removal from wastewater?
Why is it important to lower phosphate levels in wastewater?
The benefit of using a chemical treatment to lower phosphate levels in wastewater is that it can provide immediate results without the wait for construction (of a physical solution). However, traditional chemical treatments can add significant sludge removal costs; these costs can be especially extreme if the method used is the application ...
Where is phosphorus found?
Phosphorus is found in almost every fertilizer that is manufactured commercially. After crops are fertilized, the excess nutrients in the fertilizer, like phosphorous, are washed into our watershed.
How to nitrify and denitrify wastewater?
One approach that works well to nitrify and denitrify wastewater is to retrofit existing wastewater plants with particulate phosphorus membrane technologies; however, this method may lack the intended benefit of phosphate removal. Furthermore, due to the high capital cost of investment required upfront, it may take years to see a return on investment. Over the long term, however, this process can be a cost-effective solution to reduce phosphate levels.
How low is phosphorus in the US?
Some states are contemplating switching to new, more stringent standards—in some cases as low as 0.1 mg/L. That’s ten times lower than the current standard.
Is phosphorus in wastewater strict?
As phosphorus issues persist, regulations that limit levels in wastewater will become more strict. For many treatment facilities, understanding how to effectively remove phosphorus from their effluent might be a challenge, but it is surely possible.
Does phosphate cause eutrophication?
The issue is, phosphate also promotes eutrophication— the growth of aquatic plants in bodies of water, which includes harmful algal blooms (cyanobacteria). These cyanoHABs can produce noxious toxins that are harmful to both humans and animals.
Can wastewater plants remove phosphorus?
Almost all wastewater treatment plants perform at least a secondary treatment, but this typically does not provide enough phosphorus removal. To meet the new requirements, facilities can do one of two things: 1) retrofit their plants to enhance biological treatment processes, or 2) add chemistry to help precipitate out the phosphate.
How is phosphorous removed from wastewater?
In the biological removal of phosphorous, the phosphorous in the influent wastewater is incorporated into cell biomass, which is subsequently removed from the process as a result of sludge wasting. The reactor configuration provides the P accumulating organisms (PAO) with a competitive advantage over other bacteria. So PAO are encouraged to grow and consume phosphorous. The reactor configuration in comprised of an anaerobic tank and an activated sludge activated tank. The retention time in the anaerobic tank is about 0.50 to 1.00 hours and its contents are mixed to provide contact with the return activated sludge and influent wastewater.
What is the process of removing phosphorus from wastewater?
The removal of phosphorous from wastewater involves the incorporation of phosphate into TSS and the subsequent removal from these solids. Phosphorous can be incorporated into either biological solids (e.g. micro organisms) or chemical precipitates.
How is the amount of phosphorous removed by biological storage estimated?
The amount of phosphorous removed by biological storage can be estimated from the amount of bsCOD that is available in the wastewater influent. Better performance for BPR systems is achieved when bsCOD acetate is available at a steady rate.
What is the name of the compound that is added to wastewater to remove SS?
it is usually added in the form of lime Ca (OH) 2. It reacts with the natural alkalinity in the wastewater to produce calcium carbonate, which is primarily responsible for enhancing SS removal.
What is the chemical precipitation of phosphate?
Chemical precipitation is used to remove the inorganic forms of phosphate by the addition of a coagulant and a mixing of wastewater and coagulant. The multivalent metal ions most commonly used are calcium, aluminium and iron. Calcium: it is usually added in the form of lime Ca (OH) 2.
What are the processes of phosphate removal?
The main phosphate removal processes are (see picture below): 1 Treatment of raw/primary wastewater 2 Treatment of final effluent of biological plants (postprecipitation) 3 Treatment contemporary to the secondary biologic reaction (co-precipitation).
How much phosphorus is discharged from a water treatment?
Normally secondary treatment can only remove 1-2 mg/l, so a large excess of phosphorous is discharged in the final effluent, causing eutrophication in surface waters. New legislation requires a maximum concentration of P discharges into sensitive water of 2 mg/l.
Why is phosphorus removed from wastewater?
The removal of nitrogen and phosphorus from wastewater has become an emerging worldwide concern because these compounds cause eutrophication in natural water. Moreover, nitrate is a risk to human health, especially as a possible cause of infant methaemoglobinaemia [1]. An activated sludge process is commonly used in wastewater treatment, but it is often the case that the effluent from wastewater treatment plants has remaining phosphorus and nitrogen in the form of ammonium and/or nitrate. A post-treatment process is therefore required to remove nitrogen and phosphorus from the effluent. However, because such effluents contain only small amounts of organic compounds, a carbon source must be added to remove the nitrogen.
How to remove nitrogen and phosphorus from wastewater?
Nitrogen and Phosphorus Removal from Wastewater Treatment Plant Effluent via Bacterial Sulfate Reduction in an Anoxic Bioreactor Packed with Wood and Iron
What bacteria can remove nitrogen oxide from wood?
Sulfate-reducing bacteria can use wood chips or animal manure as electron donors and carbon sources and then use various types of organic substances [5]. The sulfate-reducing bacteria Desulfovibriosp. CMX have been used to remove nitrogen oxide (NO) in iron/ethylenediaminetetraacetic acid (FeEDTA) solutions [6]. Yücel et al. [7] reported that sulfate reduction (i.e., sulfide production) occurs in degrading wood in marine environments. Sulfate-reducing bacteria seem to play an important role in nitrogen removal with wood. On the other hand, ferrous ions generated by iron polarization are known to combine with phosphate to produce vivianite and other ferrous phosphates, and thereby remove phosphorus [8]. Till et al. [9] demonstrated that steel wool was effective at removing nitrogen in autotrophic denitrifying bacteria. However, iron corrosion is enhanced under oxic conditions and under high nitrate conditions. For this reason, the addition of another electron donor is useful to support the corrosion resistance. We therefore hypothesized that a bioreactor packed with iron and wood could remove nitrogen and phosphorus simultaneously over a long-term operation. And indeed, our earlier study showed that both denitrification and phosphate removal occurred in a bioreactor filled with synthetic wastewater and packed with iron and wood and allowed to react over a long-term [10].
What is the best way to remove nitrate from wastewater?
The conventional methods for post-treatment den itrification often employ methanol for the removal of nitrate [2]. Although methanol does achieve a high rate of denitrification, there are concerns about the risks posed by treatment-plant outflow containing excessive amounts of organic carbon and its flammability [3]. In practice, wastewater treatment managers hope to minimize post-treatment operation and maintenance costs. Therefore, post-treatment technologies that will enable the use of waste materials such as municipal refuse, agro-industrial residues, and wood waste are desired. In a previous study, nitrate was successfully removal from synthetic wastewater in a bioreactor packed with wood as an organic carbon source under anoxic conditions. Interestingly, the denitrification efficiency was assumed to enhance sulfur denitrification via wood degradation by sulfate reduction [4].
What is the pH of reactor 1?
The pH values of the influent and effluent of Reactor 1 were almost the same: 7.0 ± 0.3 and 7.0 ± 0.4, respectively. We assumed that the neutral pH was stable because the effluent from the final sedimentation basin contains an adequate amount of carbonate, even if the nitrifying bacteria consumed carbonate (Equation (1)).
What is the nitrification rate of a trickling filter?
In the present study, the average nitrification rate of the trickling filter was 0.17 kg N/m3∙day. This ammonia removal rate was comparable to the rates reported above. The trickling filter packed with foam ceramics has advantages in that it is a simple structure for nitrification and has lower operation and maintenance costs than aeration systems.
What are the benefits of a phosphorus dewatering system?
This is not only much more efficient, requiring far less chemical to achieve even the lowest phosphorus limits, but provides sweeping benefits that include the following: Less sludge volume. Denser, easier to dewater sludge, requiring less polymer. Better settling and cleaner clarifiers. Lower sludge disposal costs.
Is phosphate removal better than coagulants?
Phosphate removal across a broader range of pH than traditional coagulants. Better pH control, little to no need to augment with caustic to conserve alkalinity for nitrification or adjust for final pH discharge limits. Less toxic and less corrosive chemical, for a cleaner, safer plant.
Is phosphorus a drawback to wastewater?
But this lack of specificity has several drawbacks when used to remove phosphorus from wastewater, especially as discharge limits continue to be ratcheted down by regulators. In the early days of phosphorus removal, when P limits were in the 5 mg/L range, these chemicals worked reasonably well.
How is phosphorus removed from wastewater?
Phosphorus removal from wastewater can be achieved either through chemical removal, advanced biological treatment or a combination of both. The chemical remobal of phosphorus involves the addition of calcium, iron and aluminium salts to achieve phosphorus precipitation by various mechanisms which are discussed. In addition, the effects of operating conditions, especially wastewater characteristics; sludge production in terms of quality and quantity; optimisation of chemical use and re-use; points of chemical addition combined with biological treatment; alternative chemical/physical treatments and examples of full-scale applications are also reviewed.
What is the color of algae in eutrophication?
As eutrophication advances there is an abundance of algal 'blooms', often 'blue-green' algae (Cyanophycae), elimination of dissolved oxygen in the hypolimnion, and increases in the concentrations of nutrients and other organic compounds (Vollenweider, 1968).
Why Is Phosphorus a Problem in Wastewater?
While phosphorus is a necessary element, high levels of phosphorus can lead to multiple environmental complications in streams, lakes, rivers and coastal areas. A typical issue caused by elevated phosphorous in natural water sources is Eutrophication – a rampant stimulation of algae and other plants, leading to oxygen depletion in the water.
How Should Phosphorus be Removed from Wastewater?
There are several forms of phosphorus removal, the most effect effective system will depend on the characteristics of the wastewater, the existing infrastructure at treatment facility, and the effluent phosphorous level required. Project budget, operator maintenance, and form of phosphorous should also be taken into consideration.
Chemical vs. Biological Phosphorus Removal
Chemical phosphorus removal uses precipitating phosphors with an aluminum salt or iron salt. Iron salt, including ferric chloride, can provide numerous benefits to reduce scum in secondary treatment processes and manage orders and sulfides in anaerobically digest sludge.
Chemical Phosphorus Removal
Chemical phosphorus removal is a wastewater treatment process that uses iron, calcium or aluminum salts to remove phosphorus from the water. Phosphates create precipitates with metal ions and are removed with sludge in the separation unit.
Chemical System Options
There are numerous chemical systems that can remove phosphorus from water, including chemical dosing to promote p-precipitation, absorptive media for p-removal and ion exchange technologies.
Biological Phosphorus Removal
Biological phosphorus removal is a wastewater treatment process used to remove phosphorus from water. Biological phosphorus removal implementations use a group of heterotrophic bacteria to process excess phosphorus levels from water. Some of the main pros and cons of biological phosphorus removal include:
Biological System Options
Some of the most common biological system options include identification of PAO, metabolism of PAO, traditional enhanced biological phosphorus removal (EBPR), novel EBPR systems and potential EBPR systems.
What is the source of nitrogen and phosphorus in wastewater?
Wastewater contains nitrogen and phosphorus from human waste, food and certain soaps and detergents. Once the water is cleaned to standards set and monitored by state and federal officials, it is typically released into a local water body, where it can become a source of nitrogen and phosphorus pollution. Some wastewater treatment plants are able ...
Why upgrade wastewater treatment system?
Enhanced treatment systems enable some wastewater plants to produce discharges that contain less nitrogen than plants using conventional treatment methods . Upgrading wastewater treatment systems is often expensive for municipalities and rate payers, but upgrades can pay for themselves or end up saving a plant money.
How to maintain a septic system?
Homeowners are responsible for maintaining their septic systems in most cases. To protect and maintain their system, homeowners should: 1 Have their system inspected regularly and pump their tank as necessary 2 Use water efficiently 3 Not dispose of household hazardous waste in sinks or toilets 4 Avoid driving vehicles or placing heavy objects on their drainfield 5 Visit EPA's decentralized wastewater (septic) systems webpage to learn more about septic systems and EPA's SepticSmart Week Program 6 Consult EPA's guide on maintaining septic systems for more information: Homeowner's Guide to Septic Systems (PDF) (9 pp, 3 MB, About PDF)
How does a septic system contribute to nutrient pollution?
Septic systems can easily become a source of nutrient pollution if not properly maintained. Most homes and businesses send their wastewater to a treatment plant where many pollutants are removed from the water. Wastewater treatment facilities in the United States process approximately 34 billion gallons of wastewater every day.
Who is responsible for septic system maintenance?
Homeowners are responsible for maintaining their septic systems in most cases. To protect and maintain their system, homeowners should: Have their system inspected regularly and pump their tank as necessary. Use water efficiently. Not dispose of household hazardous waste in sinks or toilets.
What causes a septic system to fail?
Common causes of septic system failure include aging infrastructure, inappropriate design, overloading with too much wastewater in too short a period of time and poor maintenance.
How low is phosphorus in wastewater?
A number of water quality studies in Northwest states have determined waste load allocations which will require dischargers to achieve total phosphorus effluent concentrations that range from as low as 0.009 to 0.05 mg/l. Even as WWTP operators in the Northwest consider installing additional treatments to address water quality problem, they are also planning to upgrade capacity of their plants to accommodate rapid population growth. With many other interests competing for limited public and private resources, resolving water quality problems is often contentious and slow. Implementation of water quality improvement plans (called Total Maximum Daily Loads (TMDLs)) have been significantly delayed by arguments about the availability and cost of treatment technologies capable of achieving very low phosphorus targets.
How much phosphorus is in a plant effluent?
No chemicals are currently used at the plant to enhance phosphorus removal. Nevertheless, the final effluent typically contains between only 0.1 to 0.2 mg/l total phosphorus. Influent BOD and ammonia nitrogen were reported to be approximately 200 to 300 mg/l and 30 mg/l, respectively. Effluent BOD concentrations average about 2.2 mg/l and ammonia nitrogen is less than 0.1 mg/l.
What are the phosphorus limitations for WWTPs?
The lowest phosphorus limitation established for any of these WWTPs was a monthly average limitation of 0.05 mg/l. Operators at many of these WWTPs conveyed that if necessary, even better phosphorus removal performance could be achieved through operational changes to the existing treatment system. This is a consideration that should not be overlooked by dischargers, consultants and regulators as they consider treatment options.
What are the nutrients that are needed for aquatic life?
Phosphorus and nitrogen are nutrients that are essential for aquatic plant and algae growth. Most waters naturally contain enough of these nutrients to support native aquatic life. However, an over-abundance of these nutrients can over-stimulate plant and algae growth such that they create water quality problems. Over 1,000 waterbodies in Idaho, Oregon and Washington are identified as being impaired due to excessive nutrient loading and are included on state Clean Water Act 2004 §303(d) lists for water quality problems. The problems caused by nutrient enrichment of lakes, stream, and rivers are not unique to the Northwest states as many other waterbodies across the United States have also been identified as impaired by nutrients. Nutrient impairments affect the survival of many aquatic species such as salmon; affect the safety of drinking water supplies; affect the aesthetics of recreational areas, and the ability to navigate through rivers and lakes.
How does phosphorus affect freshwater?
In freshwater systems, phosphorus is typically the nutrient that is in short supply relative to biological needs, which means that the productivity of aquatic plans and algae can be controlled by limiting the amount of phosphorus entering the water. Many streams and lakes in the Northwest are documented to have very little capacity to assimilate phosphorus loading during the “critical” warm and dry summer period without significant water quality degradation. Large diurnal swings in pH and dissolved oxygen may occur as excessive amounts of nutrients are metabolized by aquatic plants and algae. The range of these swings is often measured to exceed the state water quality criteria established to protect fish and other aquatic organisms in their various life stages. Therefore, the amount of phosphorus currently entering these waters exceeds the seasonal loading capacity and must be reduced if these water quality problems are to be resolved.
What is the most significant source of phosphorus?
agriculture, pet waste) is often minimal during the summer months because there is typically very little rainfall runoff to flush pollutants into receiving waters. The discharges of treated wastewater can be the most significant source of phosphorus loading during these critical summer months. To address these water quality problems, state environmental agencies and the Environmental Protection Agency (EPA) are requiring dischargers to reduce the amount of phosphorus in their effluent.
Why are WWTPs selected?
The WWTPs included in this project were selected because monitoring results have demonstrated their treatment to be very effective at removing phosphorus. The reported performance at each of these facilities has been well documented by monitoring conducted over periods of several years. EPA attempted to include a variety of treatment technologies and facilities of different sizes in this evaluation. However, not all facilities that achieve exemplary phosphorus removal nor all filtration technologies could be presented in this report. A number of the WWTPs that are currently achieving good phosphorus removal are planning treatment upgrades that will allow them to also meet a total nitrogen limitation of 3 mg/l. Some information about treatment to remove nitrogen is presented in the description of the LOTT, Budd Inlet WWTP.