Mendo Island Journal — Timely. Useful. Sometimes Cranky.

Autonomous Waste Water Treatment System – Community Development Plan for Masonite Site (Part 5)

In Mendo Island Transition on April 19, 2009 at 11:18 pm


4/21/09 Ukiah, Mendocino County, North California

The development of the Masonite property into a sustainable eco-village will include its own waste water treatment system, an autonomous waste water treatment system (awwts). An aerobic digesting system (or systems) specifically designed for the site will treat the waste water, without odor, be a model of how small communities can meet their waste treatment needs and save money.

These systems are modular, autonomous (stand alone) systems, use high concentrations of specifically cultured, naturally occurring bacteria, take up very little space, costs a fraction of what current municipal systems cost, re-claims water and provides a useable product at the end of the process. In an era of drought, unsustainable development, and irresponsible water use, systems such as these will become a necessity as communities strive to afford effective waste water treatment.

An aspect of making the switch from consumption to sustainability will be utilizing new technologies that provide the same, or better, results than traditional, large, inefficient systems that cost tens of millions of dollars, take years to build and take up large tracts of land. Understanding of how bacteria, fungi/yeasts, and other micro-organisms break down and digest organic and inorganic compounds such as human waste, organic waste from food processing, industrial chemicals, medicines, hormones, harmful anaerobic bacteria and petroleum hydrocarbons has created new innovations in the waste water treatment. Some of the benefits of the digester systems are that they occupy a very small plot of land, measured in square feet rather than in acres, and they are operational within six months of final permitting, not counting time to install the collection infrastructure. The re-claimed water is clear, nutrient rich and can be used it to irrigate the agriculture land, landscaping, open areas and other non-potable water uses. Treated water ran under an Ultra Violet Light can be brought to potable standards and released directly into the environment.

There can be two approaches to the development of the waste treatment needs of the eco-village, one system to handle all of the affluent, or one system to treat the black water (containing human or animal fecal material) and a separate one for all other water treatment needs (food processing, manufacturing). If the two waste streams were to be kept separate then two systems would have to be installed during development. The cost effectiveness of a single, larger, system would have to be weighed against the cost of two smaller systems, the permitting, construction concerns and the ultimate uses for the product water. There are advantages and disadvantages to both options. A separate “black water” system could collect the human waste water and transport it to the treatment system where it would be digested then held in a storage facility to be re-used, or looped, through the toilet system. This is to say that once the waste water is treated it could be stored in a holding facility and used to supply the water for the toilet system throughout the village. The “black water” would be collected, delivered to the waste treatment facility where the organic material would be digested and the finished water returned to the storage unit to be used again and again.  If it were deemed cost effective and the toilet systems were plumbed in a continuous loop, where the treated water would be re-used multiple times, this could be a very important feature of the eco-village infrastructure.

With the black water on one system, all of the other waste water could be plumbed into another digester facility. This could be important to permitting as the requirements for grey water is much different from those of black water. Treated water from the grey water digester could be used to irrigate the agriculture land, greenhouses, landscaping, and open/green space. It could also be used to fill ornamental ponds or released directly into the environment. It is to be expected (by me) that the cost of installing two separate digester systems would still be considerably less than the cost of current, large scale, treatment facility.

The space needed for the digester systems is minimal. A system that processes 40,000 gallons per day, continuously, uses approximately 3150 square feet, or a space 100 feet long by 35 feet wide. Also, after the ground work is completed a small crew can install the digester system and have it operational in less than six months. Current municipal systems cost tens of millions of dollars, take large tracts of land, take years to install and in the end the undigested sludge needs to be excavated and trucked to a certified landfill, or other treatment facility. The digesters break the sludge down into its natural organic components reclaiming the water, saving on transportation and labor costs, and all on a postage stamp sized plot of land when compared to current municipal systems.

Single system sizes treat from 22,000 gallons per day, taking up about 0.04 acres of land, to 1,140,000 gallons per day and taking about 0.27 acres of land. Three single systems can be plumbed together with a manifold to make one large system. Three of the largest systems, on a shared manifold, would process over three million gallons of waste water per day and occupy a space of around one acre. Because they are aerobic (with air) none of the odor producing gasses, such as methane, are allowed to develop (they are anaerobic- without air), and the liquid has no “off smell”. The treated water is clear, nutrient rich and could have many applications, saving our precious potable water for other uses. If the treated water was ran through a ultra violet unit to kill any remaining organisms it would be of potable standards, increasing the potential uses for the water.

An interesting potential use of this kind of system is that storm water runoff could be collected, delivered to one of these systems (modified for the purpose) and treated for eventual use in the village; used for ornamental and wildlife pond habitat, or released directly into the environment. Bacteria and other micro-organisms can be cultured (no genetic engineering involved) to address specific pollutants (medicines, hormones, petroleum hydrocarbons), certain harmful bacteria (E. Coli, Salmonella, Staphylococcus), and various parasites and micro-organisms. This allows for the fine tuning of the waste water treatment system to meet the needs of each site and use.

The System- an overview:

There are five main parts to each treatment system: the sump, emulsification tank, biological tank, clarifier tank, chlorination/de-chlorination tank, and sand filter. There are six small electric pumps, one in the sump and four above that circulate the effluent through the system. However, the bulk of the effluent moves from tank to tank by gravity flow. The system does not depend exclusively upon the pumps to operate, except to pump the effluent up from the sump into the emulsification tank. A small electric generator is enough for this purpose in case of power failure. The system will still operate without the circulation pumps but the solids will build up on the bottoms of the tanks. The system would work and when power was returned the solids would be circulated and digested.

An Example:
Suppose we have a system designed to process about 68,000 gallons of waste water per day, or about 325 new homes for families of four. The effluent is delivered to the sump at the treatment site and pumped up into the emulsification tank at a given rate, in this case at approximately 47 gallons per minute (the rest is re-circulated in the sump). The bacteria culture is added directly into the effluent in the emulsification tank and a small pump periodically activates and re-circulates any solids that fall to the bottom of the tank, continually agitating the mixture. As more waste water is pumped into the emulsification tank the cleanest water, which is at the surface of the liquid, drops into a stand pipe that leads to the biological tank. The bacteria blend is also poured into this standpipe which then inoculates the biological tank.

The biological tank is where the main bacteria and micro-organism colony lives and does its work. Suspended in at the top of the water in this tank is a “bio-filter” made up of a hard plastic, honeycomb, structure about four inches thick and six inches around, that creates abundant surface area for the bacteria to colonize. A pump circulates the liquid from the bottom of the tank to the top of the bio-filter where it flows, by gravity, down through the colony back into the tank basin. There is a pump that periodically pulls any solids from the bottom of the clarifier tank and puts it into a sand filter, where another pump then re-circulates it to the top of the biological tank to pass through the colony once again. In this way nearly all of the solids are broken down and the sand from the sand filter is removed once a year (under most circumstances) and taken to a composting facility.

Again, the cleanest liquid is always at the top of the water level and there is another stand pipe, or drop inlet, at the waters surface. As new effluent comes in from the emulsification tank the cleanest water falls into the stand pipe in the biological tank and is taken to the clarifier. At this point the liquid is opaque and nearing completion. There is still an active bacteria culture and the digestion process continues. As the liquid sets in the clarifier tank any suspended particles settle to the bottom of the tank where they are returned, via the sand filter, to the biological tank for another go-through the colony. The water at the top of the clarifier tank is nearly as clear as regular water and as new water comes in, the cleanest drops into another stand pipe and goes into the chlorinator. As the water flows into the chlorinator unit it passes over a cartridge of chlorine tablets and into a series of chambers that is the chlorinator tank. The system is designed to allow a certain flow (47 gpm) which gives the chlorine time to volatize from the water. At this point the water is tertiary treated and ready to be used, or released into the environment. An underground cistern or surface pond can store the water until needed.

There are a few options to the system: One is to place a methane extractor at the front of the system to remove any usable gas. This is costly with today’s technology yet innovations are happening every day and this may soon become an available option. Secondly, an ultra violet disinfection unit can be placed at the end of the system, to replace the chlorinator, and the water can be brought up to potable standards.

As the financial crises mounts small communities will be forced to find new, appropriate, methods of waste treatment. The system mentioned above would cost a couple million dollars, compared to the 30, or 40, million dollars a conventional system would cost. Our community could use the extra millions to better our health, education and self-reliance.

Advantages of this system:
A fraction of the cost of conventional systems
Takes away very little land
Has no off odors
Does not use chemicals (is organic)
More efficient treatment than septic (minimal sludge)
Produces a usable product (water)
Can stand alone, or augment an existing municipal system
Can be used in combination with waste ponds for food processing, wineries, fruit packers
Requires very little energy and is solar friendly
Can be used with an underground, drip, discharge system for parks and open space
If a spill happens the bacteria continues digesting the waste
The treated water can be used to treat contaminated soil and reclaim it for use

Disadvantages of this system:
Requires more maintenance and supervision
Requires electricity
Pumps can break down
Pipes can break

A Potential Community Development Plan for the Masonite Site – Part 1
Eco-Train, Rail and Depot – Part 2
Ecologically-Oriented Tourism – Part 3
Rail to Trail – Part 4
Autonomous Waste Water Treatment System – Part 5
Community Interpretive Watershed and Visitor’s Center – Part 6
Food Processing Facility – Part 7

Small Diameter Pole Processing Mill – Part 8
Fiber Processing and Re-Manufacture Mill – Part 9

  1. Hey Earl, This is an idea that is more implementable than most people think. Thanks for your well thought out plan. I hope word gets around and some real dialogue will ensue.

  2. Packaged plants are very common. Also known as offsite water treatment systems. There are quite a number of manufacturers that do this sort of thing. Some of them can be found on my website.

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