GreenYes Digest V98 #40

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GreenYes Digest Mon, 16 Feb 98 Volume 98 : Issue 40

Today's Topics:
Benefits of recycling=20
Sludge Volume Conversion
Subsidies for Wasting: Bonds?

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Date: Sun, 15 Feb 98 20:48:59 PST From: "John Reindl" <> Subject: Benefits of recycling=20

Hi List members -

I am looking for studies/reports that document the benefits of recycling, including:

1. Jobs created 2. Energy conserved 3. Reduced use of natural resources 4. Reduced emissions from material extraction, manufacturing 5. Reduced impacts from incineration or disposal

I am especially interested in fairly recent studies (say, less than 5= years old). Any suggestions would be welcome!

Also welcome would be other types of benefits that might also be described (improved balance of payments, expanded environmental or community= support, etc.)

Thanks much,

John Reindl Madison, WI


Date: Mon, 16 Feb 1998 10:10:50 +0100 From: Ruzena Gajdos <> Subject: Sludge - ALTERNATIVES?


Dear All:

SEWAGE SLUDGE (biosolids??? - bio =3D life!)

In my opinion =B7 to discuss only management of sewage sludge is to support this "environment polluting" end of pipe solution. We add lot of energy and lose "renewable energy" and plant nutrients bound in organic material =B7 GreenYes Mailing List and Newsgroup should also discuss future systems

Sewage sludge facts from Sweden: 100 000 inhabitants produce daily about 120 tons human excreta (HE) here also called "liquid organic waste".=20 HE from 100 000 inhabitants is diluted in 30 000 000 liter water (30 000 tons). The wastewater includes water from households and industry. Value of three main plant nutrient elements NPK (nitrogen, phosphorus, potassium) in HE is about $2 500 and value of other elements as well as humic substances and energy should be added.=20 After dilution in water and then "cleaning" of wastewater 30 tons sewage sludge is produced. Value of NPK is reduced to about $500.

Current systems for "solid and liquid organic waste management" are unacceptable. All emissions are polluting losses. It is like driving car from 1930 or 1970.=20

We need EFFICIENT LOCAL SYSTEMS where our organic wastes, residues or fuel crops are transformed in facilities with modern technology to energy rich BIOGAS and well-tailored BIOFERTILIZERS.=20

We need to develop better systems and methods for collection, preprocessing, processing of both solid and liquid organic waste and also for application of products. Whole chain have to be hygienic, user friendly and economic.

As long as companies sell their old-fashioned systems wastewater treatment or for composting mixed household waste and sewage sludge using misleading propaganda it is very difficult for scientists to write about alternative sustainable solutions.=20 In spite of that, my responsibility is to inform - take it or leave it.

Hopefully waiting for fruitful discussion

Ruzena Gajdos

********************************* Ruzena Gajdos AgrD Visirvagen 8 246 33 Loddekopinge Sweden Phone: +46 46 709317.=20 Phone/Fax: +46 40 301103=20 Mobile phone: +46 707 331120 E-mail: *********************************


Date: Sun, 15 Feb 1998 20:12 -0800 (PST) From: "Lacaze, Skip" <> Subject: Sludge Volume Conversion

1. I think that Roger's conversion factors (below) result in a range of 0.6 to 0.95 tons per cubic yard (rather than cy / ton).

2. The conversion tables I looked at do show that water has a density of 8.34 lbs/gallon, as Mr. Biddle says. However, the densities shown below for sludge are actually both higher and lower than this, and I have to believe that the lowest figures are from samples with voids. There is a nice conversion table at

1 cubic yard of water =3D 201.974 gallons, liquid (US) =3D 1865.55 lbs

The Missouri site, at=20 uses the 8.34 lb / gallon figure for "biosolids" and says that biosolids are usually handled as a liquid, at 3 - 6 per cent solids, with a "consistency= =20 of a chocolate malt." For purposes of calculating the loads to be placed on sludge handling equipment, or converting volumes to weights to estimate the costs of sludge transportation, I suspect that a PE would find use of 8.34 pounds to be a perfectly reasonable first approximation, as long as the design was conservative enough to provide for the possibility of even higher densities for the actual material handled.

I don't think that any kind of a slurry like this could weigh much less than water alone. Also, whether you are considering a liquid sludge, or a dewatered, "spadable," sludge of more than 30 per cent solids, you should expect a density similar to water's, or higher. After all, sludge is what settles out. The supernate should have a specific gravity greater than 1, since it contains lots of dissolved solids. The solids that settle have to be heavier, or they would float. (The stuff that floats, the scum, is skimmed off the liquid in the primary digesters -- it contains lots of fats and greases; more stuff floats to the top of the anaerobic digesters (mostly organics that are holding onto digester gas, I think), and this may end up in the output sludge or may be handled differently.)

I suspect that the only way for sludge to end up with a bulk density lower than that of water, and to weigh less than 1855 lbs per cubic yard, is for= =20 it to contain lots of very low-density material (floc, perhaps?) or for it to= =20 be dried and/or aerobically composted (not just de-watered) and then handled so that it ends up with voids.

I agree that it would be best to test the actual density of the sludge you are working with if great accuracy is needed.

Skip Lacaze Supervising Environmental Services Specialist Integrated Waste Management Division Environmental Services Department 777 North First Street, Suite 450 San Jose, CA 95112-6311

phone: 408/277-5533 vm: 408/277-2280, box 8 fax: 408/277-3606 ------------------------------------------------------------- GreenYes Digest Sat, 14 Feb 98 Volume 98 : Issue 38

Comment on Sludge Volume Conversion (2 msgs)

Date: Fri, 13 Feb 98 10:31:25 -0800 From: Subject: Comment on Sludge Volume Conversion

Dear All:

David's comments regarding the impact of moisture content on sludge density are correct. I consulted a listing of conversion factors published in 1991 by the CA Integrated Waste Management Board and found the following data for dewatered sludge:

14.7% solids =3D 1552.5 pounds / cy 28.4% solids =3D 1199.00 " " 24% solids =3D 1801.00 " " 17% solids =3D 1769.00 " " 38% solids =3D 1890.00 " "

This results in a density range of roughly .6 to .95 cy / ton.

In addition, the State of Missour's Extension Service published in 1995 an interesting fact sheet on biosolids including a list of conversion formulas that may be useful for your purposes. This document can be consulted online= =20 at:

I hope this helps.

Roger M. Guttentag

=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D

At 08:45 PM 2/12/98 EST, you wrote: >In response to your sludge volume-weight conversion index, the number >8.34 pounds per gallon is the conversion factor for water. As one of the >heavier substances out there, it is likely that sludge weight is a bit >lower, but not much-depending of course on how efficient a de-watering >system is. To get a real number for your mix, probably the best thing to >do would be to fill a bucket with sludge and put it on a scale. Any >engineer worth his/her PE will know that you are using a water conversion >factor when they see your math. You may want to be accurate just for the >sake of credibility. > >It may not matter much, but at least you'd know fer shuah! > >David Biddle, >Philadelphia, PA > > >>From: (Rebecca Brown) >>To: (GreenYes), (Cheri=20 Kennedy) >>Cheri, the head of our water pollution control facility gave me >>this formula: sludge pounds =3D volume (in million gallons) X >>concentration (in milligrams/liter) X 8.34. (8.34 is >>pounds/gallon). Hope this is correct for what you're after. >>Rebecca Brown >>City of Woodland, CA >>530-661-5969 >> <snip>


Date: Sun, 15 Feb 1998 10:54:38 -0500 (EST) From: Greg Smith <> Subject: Subsidies for Wasting: Bonds?

Hi, Erich. Here's a local example for you -- the Mongomery County, MD garbage incinerator, fired up commercially in 1995. 1800 TPD. $360 million in bonds, most of it for the incinerator itself. Over $700 million with interest. The Montgomery County recycling facility cost roughly $10 million, and has a capacity of about 800 TPD -- commingled, ONP and yard waste. The yard waste is composted elsewhere.

Pardon my ignorance, but what is a PAB vs. other bonds?

If I remember correctly, R.W. Beck overestimated the incinerator throughput by 21 percent in the first year of operation. Costing about $100 per ton, or more, to burn. County created special tax to keep the incinerator afloat. Mixed paper recycling and quantity-based fees not coming on line with any speed.

Greg Smith Eco-Civic Network and Waste Prevention Coalition

On Thu, 12 Feb 1998, Bill Sheehan wrote:

> Date: Thu, 12 Feb 1998 13:08:09 -0500 > From: Bill Sheehan <> > To: GreenYes <> > Subject: Subsidies for Wasting: Bonds? >=20 > [The following is forwarded from Erich Pica of Friends of the Earth, who > is working, together with Taxpayers for Common Sense (lead), the > Materials Efficiency Project and the GrassRoots Recycling Network, > on preparing a =93Green Scissors for Recycling=94 report.] >=20 >=20 > I would like to send some questions about the Private Activities Bonds > (PABs) over the network. Here is some background and questions I am > posing. >=20 > In the subsidy report, we are looking at the effects that PABs > have on the recycling industry. Originally, we assumed that PABs were > used specifically to fund incinerator plants. Unfortunately, we found > information that states PABs can be used to fund solid waste, hazardous > waste and recycling facilities. If we advocate against PABs, we would be > attacking a potential funding source for the recycling industry. >=20 > These are questions we have about PABs. >=20 > 1. Are recycling facilities being funded by PABs? >=20 > 2. How many incineratos are being funded through PABs? >=20 > 3. Are recycling facilities at a disadvantage for receiving PAB funding > because they are relatively less capital intensive than incinerators? >=20 > 4. Can we advocate ending incinerator funding through PABs while keeping > the status quo for PAB funding to recycling facilities? What are our > arguments to justify this? >=20 > 5. What other potential waste subsidies put recycling at a competitive > disadvantage? >=20 > Thank you for your help, >=20 > Erich Pica > Policy Associate > Friends of the Earth > (202) 783-7400 > >=20 >=20 >=20 >=20 >=20

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End of GreenYes Digest V98 #40 ******************************