Is Municipal Sludge useful?

Once Municipal waste water is treated, the sludge, also known as BioSolids, are dried and applied to land as fertilizer. There is a lot of controversy over this use of sludge. Harmful effects and beneficial effects with data and testing on both sides are hotly debated. All this resulted in the EPA Part 503 rule dealing with the disposal of sludge on land.

One of the best accounts of the effects of the bugs/pollutants in the sludge after treatment, is in the book - The Big Necessity. A chapter called BioSolids explains the Citizens and the Municipality's point of view. a must read.

EPA rules referred to as the 503 rule, addresses the pathogens ( bugs) in the residual sludge ( Biosolids) . States need to adopt this or make there own rules up. These rules are very difficult to follow, police or implement. so there is uncertainty and confusion with each state having it's own set of codes and rules.

In a recent publication of the EPA, about 3300 water treatment plants were tested for residual pollutants ( these are plants treating > 1 Mil. gallons a day ). Trace elements of Pharmaceuticals were found in most of the effluent. Antibiotics and endocrine disruptors appear to be the problem pollutants that persist ( although in Trace amounts ) in the treated water.

Now the EPA will study the "fate an degradation rate" of these pollutants .. that is , how fast do these pollutants degrade to become harmless to humans, and what concentrations do they need to be in, to be harmful in the first place.

Countering the EPA's report is a report out today that shows estrogen in mineral water bottles, leaching out of plastic as XenoHormone ( compound that mimics a hormone)



... to be continued..

Manure: new source of renewable energy

In 2008, Dairy Manure from 3 stares contributes to half of 125 digesters installed in USA. PA, NY and WI are large Dairy states with the most installed anaerobic digesters.
In Europe, UK and Germany lead the installed base with > 70% energy generated by digesters. There are 1000s of Digesters in Europe and only 125 in USA. We have tapped less than 2 % of the energy potential from this renewable source: Manure.( 6500 farms are potential sites for digesters) Environmental Impact

Digester Gas, Methane (CH4) is 20x more harmful than CO2. Burning CH4 and converting it to energy, solves the GHG emissions problem and CO2 offsets (direct and indirect) can be encashed with the imminent cap-and-trade regs system.

Technology

One of the problems with the experience of farmers in USA is the bedding contamination in the digester. Most large farms (CAFOs) in USA have cows bedded on Sand. Cows on Sawdust or woodchips are prone to higher cull rates and poor milk quality. Cows on Sand, on the other hand, have longer life, live healthy and produce better and more milk.

But sand clogs the digester. There is need to eliminate the sand from the digester before it can get to the digesters. Over the last decade, 90 out of 100 digesters stopped working due to contamination, or lack of proper anaerobic process technology.

Nowadays, complete mix technology, a process started in Europe, is catching on.. The issue with sand is being addressed with a removal process installed in farms with about 95% to 99% removal of sand. The Parkson sand saver can be viewed on YouTube.