Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Effect of applying sewage sludge on forestry land

23.03.2004



100,000 tons of sludge is produced annually in the Basque Autonomous Community (BAC) at waste water treatment plants (E.D.A.R). Under new legislation it will be obligatory to install these sewage water treatment plants in those urban areas of more than 3000 inhabitants, which in turn will mean, in the medium term, a considerable increase in the amount of sewage sludge generated.

The application of this sludge to forestry systems is being put forward as a solution to the ever-increasing production of this by-product of urban populations. The effects on crops and our natural resources that the application of this E.D.A.R. sludge might have should be thoroughly studied in order to preserve the environment and manage an organic residue such as this in a sustainable way. Thus, applications of treated sludge should avoid:

  • excessive leaching of NO3 into subterranean waters and
  • excessive load of heavy metals, organic contaminants and undesirable microorganisms into the soil, in order to protect both soil and persons from possible contamination.

The transformation of waste sludge in soils is influenced by the properties of these, given the ongoing physical, chemical and biochemical processes therein. All these reactions affect the end-products of the breakdown in the soil and speed of such breakdown. Various studies of sewage sludge applications have shown that they affect the potential leaching of NO3 and a greater loss through NO3 leaching is experienced in those areas subjected to successive applications of the sludge than in those places untreated with sewage sludge. Nevertheless, more information is needed about the effect of such successive applications of sewage sludge regarding exactly where the nitrogen ends up in forest soils. This information is necessary in order to avoid NO3 leaching from taking place.

No study of the this use of sewage sludge on forest soils in the BAC has taken place to date, given the difficulty of the application of such material (the extensive land surfaces to be treated, the large quantities of sludge to be transported, a terrain difficult to work with machinery). One of the aims of this research was to study the NO3- y NH4+ ions in lixiviations after repeated applications of EDAR sludge on forest soil planted with Pinus radiata.



To this end, the waste sludge, previously centrifuged (dry material ~ 20%), was transported and deposited at the edge of sectors of forestry land belonging to Lezama municipal council in Bizkaia. This soil shows the typical features of heavy leaching. The soil was sampled annually before each application. The lixiviations were obtained at depths of both 25 cm and 50 cm after a significant rain event. The levels of NO3- and NH4+ in lixiviations were inversely proportional. The levels of ammonia were highest in the first 400 days of the experiment, and at its maximum between the 66th and 266th days. This tendency was common at both depths studied, although the concentrations of NH4-N at 50 cm were generally less. Apart from this, the levels of NO3-N in lixiviations began to rise until day 176, hitting a peak of concentration between days 345 and 413. A second concentration peak of NO3-N was detected about day 594 at the 25cm depth and another one between days 774 and 802 at 50 cm depth, while the NH4-N level remained low. Under current investigation is how the prior application of waste sludge over successive years influences the physical-chemical features of the soil, the loss of nutrients in lixviations and the accumulation of heavy metals.


Contact :
Garazi Andonegi
ELHUYAR Fundazioa
garazi@elhuyar.com
(+34) 943363040

Garazi Andonegi | Basque research
Further information:
http://www.basqueresearch.com/berria_irakurri.asp?Gelaxka=1_1&Berri_Kod=435&hizk=I
http://www.neiker.net

More articles from Ecology, The Environment and Conservation:

nachricht Listening in: Acoustic monitoring devices detect illegal hunting and logging
14.12.2017 | Gesellschaft für Ökologie e.V.

nachricht How fires are changing the tundra’s face
12.12.2017 | Gesellschaft für Ökologie e.V.

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: First-of-its-kind chemical oscillator offers new level of molecular control

DNA molecules that follow specific instructions could offer more precise molecular control of synthetic chemical systems, a discovery that opens the door for engineers to create molecular machines with new and complex behaviors.

Researchers have created chemical amplifiers and a chemical oscillator using a systematic method that has the potential to embed sophisticated circuit...

Im Focus: Long-lived storage of a photonic qubit for worldwide teleportation

MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.

Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

Engineers program tiny robots to move, think like insects

15.12.2017 | Power and Electrical Engineering

One in 5 materials chemistry papers may be wrong, study suggests

15.12.2017 | Materials Sciences

New antbird species discovered in Peru by LSU ornithologists

15.12.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>