Sewage Treatment Plant

I know a sewage treatment plant in my area that has a design capacity of 1.3 million gallons per day. It normally runs at 250K to 400K gallons per day. It has a 20 million gallon equalization basin. There are aeration basins, settlement basins,chlorinator area and areas to dry sludge. The whole site is approximately10 acres, and seems spacious.

Thanks wcfloyd, but it I reckon our size is 70m│/day (264KGPD) maximum..10 acres is spacious just eats our whole site

So, hire a credible engineer to figure the needed capacity.

As is typical, you don't give a location.

I once encountered a developer who had paid $1,000,000.00 for an acre of land then demanded that the regulatory agency let him increase the housing density to 2x normal.

His logic? He had to have the outlandish density or he would not make a profit on his investment.

Get real.

yes lynlych I'll do that on the next stage of the design. As for concept design space and volume, can't we have a ball park figure on this? probably we'll just seek help from the local STP contractor to give us a rough estimate of the area.

thanks

"local STP contractor" is a good move. Credibility is everything. _{The good ole boy network is alive and well, everywhere.}

Good luck. Overlook the cynicism.

Foot-print does not equate to size for of any given WTP. It´s technology dependent. Whereas lagoons are space-intensive (but have landscaping appeal) a sequential batch reactor sistem has the smalles foot print, ball park in your case 60-70 m2..

Like you said, the size will depend on the technology and system(s) used. 20 years ago we had a bacterial demo pilot plant for about 10,000 people on a 40 Feet trailer, but that was definitely too small to last, and we had still waste components to handle. (mostly for solidifying)

many thanks to all of you guys. We seeking help for local STP contractor and be involved on the early stages of the design.

Your local STP guy will also want to know stuff about how seasonal the utilisation will be. We have a couple of areas that have a 300% increase in holiday times and so the plant that we use is like multiple "chains" in parallel that can be enabled as the population grows and falls.

Also, is it likely to be "domestic only" or will there be resturuants and deep fry materials etc. etc.

This is our baby and at present the left hand system is in idle mode, just aerating water. The ponds in the background are exfiltration ponds where the water returns through sand beds bace to wetlands nearby.

basically its just a sort of a country club resort, with 20-bed hotel,100 staff accomodation and 5 to 8 restaurants. As what you have mentioned the facility will be seasonal.

BTW, thanks for the picture.

The system you describe is very small - the system shown in the picture would handle flows 10 times your requirement. There are companies who specialise in systems for resorts. One such system that I have seen recently uses a disc type bioreactor which mimics SBR's on a continuous process. The disc reactor is a tank with a shaft turning a large number of discs within the tank. The bacteria adheres to the discs and alternates between anoxic and aerobic phases depending on whether they are underwater or exposed to air. These systems are ideal for resorts and for an application such as you have suggested would need about 80 - 100 m2 of space in total. Alternatively, depending on your location, I have also seen a system in Arnhem Land in thye north of Australia which uses a fine screen to remove chunky bits, with the remaining effluent discharged to a reed bed system in an adjacent creek. Two kilometres downstream the water is crystal clear and disinfected by sunlight. As a previous contributor noted, this is one of those scenarios where you cannot give us too much information if you want us to help.

The size of the plant is depentent on many factors some of which are the min/max flows, concentration of waste and type of treatment required.

Any info on the amount of B.O.D AND C.O.D expected in the plants and/or residential inflow.

The same info is required for what is allowed in the plants outfall.

This with the type of treatment and type of waste commericial or residential will give you the an estimate of the size of the facility required.

Talk to a Waste Water engineer

Okay, first you need to know is what your discharge permit allows in the way of effluent discharges, because that above all else will dictate what unit processes will be included in your treatment trains. In the USA, this permit is called a SPDES permit. Effluent discharge limits are based on the type and class, as well as seasonal flow rates of your receiving water, whether it is a stream, river or a lake. If this project is in the USA, the SPDES Permit is promulgated by the State environmental regulatory agency where the plant is to be located.

To roughly calculate the size of the individual unit processes I suggest that you obtain a copy of the Ten State Standards as a starting point only. You will also need to have a whole bunch of USEPA and state standards and reference books. On top of all that, you'll need to perform the necessary bench laboratory tests and analysis' as well as conduct extensive pilot plant studies on the raw sewage you will be treating. This is something a Consulting Engineering firm specializing in Wastewater Treatment Plant design should be doing, not a developer or his Contractor as this appears to be a plant serving a large subdivision. If it's for an industrial manufacturering site, then it's another animal altogether!

@thanks BigPete and Moosie for your contribution, I'm getting closer of becoming a wastewater engineer. Project will be in middle east so I think extreme temperature can affect the kind of treatment??? Nevertheless you guys are right that it's is a scope of wastewater consultants not ours so we are beginning to coordinate these things with them..

Thanks a lot guys

Temperature is not a problem with most plants the warmer it is the better the bugs work.Smallest footprints in order of preference MBR (Membrane bioreactor) effluent can be used for swimming pool top up without further treatment. SBR (sequencing batch reactor) basically the first half of an MBR Plant without the membranes. RBC Basically a trickling filter system in a box (gives good results in a very small foot print) but requires further treatment before disposal. ITT water and wastewater should be first contact they are worldwide and they give free advice on most things www.ittwww.com or PMTwater.com

Thanks coconutpete. Its very MBR's capabilities are quite interesting. we are planning to use the effluent for landscape irrigation. also thanks for the links

Here are some providers of package sewage plants in Canada and USA that might work for you. I suggest you also talk to Brian Jobb at www.msfilters.com. Brian teaches and specializes in what you are looking for. These are all small footprint plants and it will certainly depend on local regs on where and what you can discharge.

Two additional comments.

You will definately need to consider "odour" issues in your storage and treatment. If space is an issue, then you might need to throw a bit of additional technology at that.

The other is that for re-use, if at all possible, use underground soaker irrigation methods so that public contact is avoided/eliminated.

Another "out there" idea is to run the stuff through an RO process and re-cycle it back to the residents. It is feasible!!!!!

Hi,

just two comments, one of these may be considered off-topic:

1)
Temperatures in the middle east may of course be an essential parameter for the process selection and plant design! Closed tanks in bright sunlight, might for example adsorb too much sun, resulting in a temperature rise ind the tank or at least at tank walls. Most micro-organisms respond quite sensitive if exposed to high temperatures, and to variations in temperature - just think about differences between day and nicht time. So excess heat-up or temperature fluctuations can lead to a reduction of process efficiency!

2)
Have you ever heard about women in engineering? I certainly do not want to play this issue too high, but sometimes it is really embarrassing, reading an address like "..some of you gents...". To me it seems to be a typical behaviour for thread openers from some "specific" countries! - -sorry, that this comment just hit you, but I had to comment on this issue at least one time.

nudnik