What is the most effective way to reycle septic waste commercially?

Question

Volume 10 million litres per year ?
Cost of set up?
Land area required?
Quality of water recovered?
End use of reclaimed water=farming

Answer 1

In India, about 300 cities are there with good sewage treatement plants. Nearly, 100 million litres of sewage water per day is generated and 10-15 million kg of sludge per day has been generated. These waste water and sludge is rich in plant nutrients like nitrogen, phosphorus, potassium and other micronutrients. Developing countries like India are facing problems of rapid urbanisation and industrialisation and vagaries in monsoon rainfalls on one side and on the other side, the scarcity of irrigation water and rapid escalation of fertiliser cost are the everincreasing problem. At this juncture, these all nutritious wastes are to be effectively dispossed in a productive manner. Application of these wastes in the agricultural land is the only safe way of disposal. The only concerns in this process is the existance of harmful disease causing pathogens (E. coli and other bacteria) and possible existance of heavy metals which are toxic to plants, animals and human being. Very careful monitoring, evaluation and controlling of these problems will pave way for effective utilisation of these wastes in agriculture. Generally, the waste water plants are set up by the city corporations, munipalities etc. Even private people can also come forward to take up this process and can earn more, because, it can give more profit. In Tamil Nadu, the big cities like Madurai, Coimbatore, Trichy etc. are having this type of treatment plants. Here, once in a year, the sewage sludge is auctioned and farmers are purchasing these sewage sludge at higher rates to apply them in their farm holdings. This is very good organic manure. Now a days, the organic farming is gearing like any thing. So there is vast scope of utilising these waste water for irrigation and sludge as organic manures. In one of my Ph.D. programmes, I used this sewage sludge @15 tonnes/ac in sunflower and soyabean. This reduced nearly about 25% of commercial inorganic fertiliser requirement in these crops. The soil fertility and physicial properties also improved. Even, in the farm holdings near Avaniyapuram of Madurai, the farmers are using treated sewage water for cultivating paddy in their fields. In another experiment of mine, application of sewage water and sewage sludge in banana field reduced the input of commercial fertiliser to 80% and thus saving of cost due to fertiliser by 20%. Another advantage of using treated sewage water is the reduction of nematode population and soil born pathogenic fungus or bacteria in the agricultural lands. This may due to the presence of limited quantity of heavy metals like Mn, Fe, Zn in chelated forms with organic molecules. These structures are similar to that of the commerically available fungicids like Zineb, Maneb etc.
In countries like Israel, where scarcity of irrigation water is the major problem, they are using treated sewage water in drip irrigation system and they show very high productivity in their agricultural lands. In some of the Europian contries, nuclear radiations are used to kill the pathogens in the sewage water before using them in the agricultural fields. In India, liming (addition of calcium oxide) to sewage water settling treatment tanks as disinfectant. The quality of such septic water is also very good for irrigating agricultural lands. Thus utilisation of sewage water and sewage sludge is boon the indian agriculture.

Answer 2

Okay, since you're mention litres, I'll run under the assumption that you're not American. Here in the States, we call this tertiary sewage treatment, meaning that the sewage goes through three separate stages. In the primary stage, the sewage is sprayed out into large tanks, where any solids then settle to the bottom to be scraped out by some lucky soul later on. Often, a chemical is added to the sewage in this stage to chelate or aggregate the solids and particulate matter into larger, heavier clumps to help the process along. In secondary treatment, the mostly clear liquid waste is filtered, and bacteria are added and the sewage is circulated to keep it aerated while the bacteria digest organic matter that didn't settle out in primary treatment. This takes time and a lot of storage. Finally, the sewage is chemically treated, first with strong acids and caustics to kill anything that made it through secondary treatment (including the bacteria that was added initially), then other chemicals to make it neutral and safe. It's filtered one more time before being pumped out for use as gray water or released into the environment.

This costs a lot (no idea how much, but it'd be in the multi-millions of dollars), and each treatment plant would require... um, 3 hectares apiece (guesstimating based on the sewage treatment plant near where I live). The quality of the water is considered drinkable, though no one wants to just because they know where it came from and it has that stigma, so it's used for agriculture or cleaning purposes but not for human consumption.

Answer 3

Open a lemonade stand?