Example: Effect of Loading Rate and Planting on Treatment of Dairy Farm Wastewat
ID: 1709803 • Letter: E
Question
Example:
Effect of Loading Rate and Planting on Treatment of Dairy Farm Wastewaters in Constructed Wetlands – 1. Removal of Oxygen Demand, Suspended Solids, and Faecal Coliforms (1995)
New Zealand
Dairy farming is a major primary industry
Dairy cattle numbers (3.5 million) exceed human population
“…dairy parlour wastewaters composed of excreta and mud which is washed from concrete holding yards with high pressure hoses, waste milk, and milking equipment cleaning water (including detergents, acid and alkalising agents, and sanitizers), are commonly treated in two stage oxidation ponds before discharge to surface waters.”
Effluent water still contaminated: Oxygen Demand, Suspended Solids, and Faecal Coliforms
Solutions
Construct wetlands to remove BOD, SS, and FC
Natural wetland acts as a watershed filter, a sink for sediments and precipitates, and a biogeochemical engine that recycles and transoforms some of the nutrients
Wastewater nutrients flow through shallow gravel-filled channels which emergent aquatic plants grow hydrophonically
Sedimentation, filtration, digestion, oxidation, reduction, adsorption, and precipitation achieved
Pros
Low cost and low operation & maintenance requirements
Good performance, suited for small-scale on-site applications
Low-tech method, less chemical and energy needed, lack of reliance on machinery
Natural appearance and ecological benefits (wildlife habitat enhancement)
Cons
Requires large land areas
Quality assurance
End Of Example
Question: I need come up with solutions similar to the ones you see on the example above for mu case study.
case study: Ohio river
What are the contaminants:
23 Million pounds were dumped in the Ohio River in 2013.
Main Source of the pollution of the ohio river is due to discharges from industries.
92% of toxins were nitrate compounds, moslty from an increase in steel factories.Nitrate pollution due to farm run-off from to nitrogen-based fetilizers. Nitrated then contributed to the toxic algae blooms and the oxigen depleted gulf of mexico.
380 pounds of mercury were found.CHemical such as mercury are also present from coal-fired plants. Much of the mercury comes from runoff or mixing pools, the mercury levels need to go down — you can’t really eat the fish if you catch them
Storm water runoff, agricultural run off
Pathogens from ecoli and coliform bacteria. result of rain which flushes bacteria into the Ohio River from such sources as overland runoff and combined sewers. Bacteria levels can rise rapidly as a result of rain, and in the larger urban areas, generally drop back to normal levels within 48-72 hours. Bacteria conditions in the Ohio River during extended dry periods are generally below the criteria, (with the exception of certain known areas), while bacteria conditions after rain may likely exceed the criteria, (with the exception of certain known areas), while bacteria conditions after rain may likely exceed the criteria.
Point source polution: A.K Steel a company locared in Rockport Indiana which accounts for 70 percent of the Ohio rivers toxic metals.
one common factor between the river and the algae bloom is power plants. because the algae is caused by nitrates and phosphates and some of these power plants are using nitrates and phosphates in their scrubbers to get rid of sulfuric acid,
http://www.newsrecord.org/news/environmental-protection-agency-calls-ohio-river-the-most-polluted-in/article_5d6a04a6-9304-11e5-bf5c-c70efe02bafb.html
However, threats continue from stormwater runoff, agricultural runoff, mercury deposition from coal-fired plants, and millions of gallons of untreated sewage that flow into the river each year from sewer overflows.
92 percent of the toxic discharges were nitrate compounds — most of those from AK Steel's Rockport, Ind., plant — and yet the river still meets human health standards for nitrates. He also shifted the blame for nitrate pollution in the Ohio to farm run-off from nitrogen-based fertilizers, which is not required to be reported in the EPA's Toxic Releases Inventory. Nitrates contribute to toxic algae blooms and the oxygen-depleted Gulf of Mexico dead zone.
some chemicals are more troublesome than others, and "a little bit of mercury causes a lot of problems,though mercury ranked 48th by weight of toxic chemicals or metals dumped into the Ohio in 2013, it is persistent in the environment. Mercury discharges in the Ohio are also increasing. Plants would need to demonstrate measures taken to reduce their mercury discharges, Heath said, adding that a mixing-zone ban for new industrial facilities remains in effect.
The Ohio River once again leads the nation for industrial pollution.
According to the Ohio River Valley Sanitation Commission, most recent Toxic Release Inventory report for the Ohio River, 23 million pounds of chemicals were dumped into the Ohio river by industries and businesses in 2013.
Harmful algal blooms can cause taste and odor problems in drinking waters, pollute beaches with scums, reduce oxygen levels for fish and other animals, cause processing problems for public water supplies, and may generate toxic chemicals. Knowing what triggers HABs is key to reducing their occurrence and impacts. HABs may be minimized, and some completely avoided, by reducing the nutrients and pollutants added to the water.
Low cost and low operation & maintenance requirements
Good performance, suited for small-scale on-site applications
Low-tech method, less chemical and energy needed, lack of reliance on machinery
Natural appearance and ecological benefits (wildlife habitat enhancement)
Explanation / Answer
Solution :
A biological treatment plant need to be setup to remove nitrate compounts with the help of denitryfying bacteria.
Nitrate compounds help algea to grow and bloom in a haphazardous manner.
Nitrate is removed from wastewater in with the help of biological treatment using nitrate-reducing (denitrifying) bacteria. Added methanol or a comparable carbon source typically serves as an electron donor for the bacteria. In this reaction, denitrifying bacteria reduce nitrate to nitrogen gas, oxidize methanol to carbon dioxide and create more bacteria (biomass).
Mercury content can be reduced by use of settling ponds and using scrapers to remove the settled solids including mercury. Mercury density is more hence it will settle down in settling ponds. The capacity can be designed as per the flow rates.
Pros :
1. Biological treatment plants are environmental friendly. Contaminants are mostly inorganic.
2. THey are energy efficient.
3. Operating cost is lower since some part of bacteria is already present in wastewater and can be reused.
Cons:
1. Initail cost of investment is comparatively higher for biological treatment plants.
2. Area required is higher compared to other treatment method.
3. Operation depends on climate and environmental factors.
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