Slurry

Aeration & Oxygenation systems

Environmental & sustainable water treatment

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Farm Waste Slurry treatment

Equipment | Installation in effluent treatment

Dryden Aqua manufacture air diffusers and aeration systems for the treatment of farm slurry waste. The diffusers may be used for mixing of the water or as part of a treatment system.

The standard diffuser is one of our 3m long diffusers code 6.2.10 rated at 9 to 10 cubm/hr of air. The diffuser is fitted with a 1/2" hose tail, for connection on to 1/2" flexible hose. If a number of diffusers are required to treat a tank, a large diameter polythylene pipe is fitted around the perimeter of the tank. The 1/2" hose is connected onto the air ring main, and the other end to a diffuser. The diffuser is then dropped into the tank. If there is a lid on the tank, you can drill a 50mm diam hole and drop the diffuser through the hole. The Dryden Aqua diffuser has its own internal ballast so it will stay on the bottom of the tank. There is no need to empty the tank or secure anything to the base of the tank. Installation and maintenance is therefore quick and simple.

The number of diffusers used will dictate if you just want to mix or if you want to treat the effluent to produce a product that will become a better fertiliser. The treatment system will remove >95% of the free ammonium nitrogen and convert it into nitrate and bacterial cell biomass. Close on 100% of the BOD will be removed and approx 80% of the dissolved COD to give a very consistent high quality liquid fertiliser. The treated waste water, may be filtered through a screen to remove docken seed.

The aeration system should ideally be operated as a series or two or more tanks or lagoons connected by an overflow pipe. The tanks / lagoons are operated as sequencing batch reactors, this helps to keep the good bacteria in the system, and clarifies the effluent at the same time.

A typical system for 500 cattle would comprises of 50 diffusers code 6.2.10 and one air blower fitted with a 22 kw motor. There will be two or more tanks connected in series, and the total volume in the tanks should give as long a residence time as possible, we recommend 40 + days for best results.

Table. The treatment or mixing of animal slurry, the table gives the number of animals that can be treated using just one diffuser code 6.2.10 delivered with 10 cubm/hr of air at approx 10 psi pressure.

Animal	Application	Raw slurry with solids removed down to 1000 microns	Raw slurry
Animal	Application	Number of animals per diffuser 6.2.10	Number of animals per diffuser 6.2.10
cattle	mixing	40	20
cattle	treatment	10	5
swine	mixing	40	20
swine	treatment	20	10

You can use the above table to size a mixing of water treatment system. It is always best to remove the solid matter prior to treatment. If we assume a system with 1000 head of cattle and you want to treat the effluent to a high standard, then you will require 1 x diffuser for every 10 animals. For 1000 animals you need a 100 diffusers and 2 x 22 kw air blowers each delivering 500 cubm/hr of air. The raw slurry should have a residence time of up to 30 to 50 days in the treatment tank in order to give the best possible effluent quality.

A partitioned under-ground tank 3 sections, 4m deep 12m x 60m and
800 cattle, system fitted with 60 diffusers and blue air ring main.

Slurry ( desludged)

The solid matter should be remove from the liquid component. The solid matter can be composted and the liquid matter treated. A typical cattle farm raw waste will have the following characteristic

56 litres of waste liquid per day at 6% solids

600 g/bod and approx 1.2 kg COD

100 g of ammonium nitrogen

30 g of phosphates

Residence time of slurry in aeration tank 30 to 50 days, summer - winter

The system may require additional calcium and pH correction using Magphlow, to stop the system from becoming acidic. However at the start up of a new system with high ammonium levels acid may need to be added to bring the pH down to 7.5. Once the bacteria established, the pH will start to fall , and this is when you need to add the Magphlow media.

Note.

The system will not only eliminate odour, and mix the waste, but with the addition of AFM you have class 1 irrigation water / fertiliser

air blowers by dryden aqua for a farm slurry water treatment system

Roots type air blowers, 30 kw motors, approx 20kw power absorbed,
600 cubm/hr of air discharging into a 125mm air ring main fitted with 60 diffusers.

Tertiary treatment and Final polishing

If the aeration system is operated as a sequencing batch reactor (SBR) then the final effluent will be of a high quality. The suspended solids load may range from around 5 to 100 mg./l of suspended solids. With regards to suspended solids the effluent water quality will tend to be a variable, which is linked to the quantity and quality of waste entering the system.

In order to eliminate the variability of the the waste water with respected to solids load, tertiary treatment may be required after the SBR aeration systems. For a typical schematic for the system

schematic of system click here

Decantation tanks click here

ZPM click here

APF click here

Drum filter click here

AFM filtration click here

Skid mounted AFM treatment system for up to 5 cubm/hr