Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Effect of applying sewage sludge on forestry land


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
(+34) 943363040

Garazi Andonegi | Basque research
Further information:

More articles from Ecology, The Environment and Conservation:

nachricht Invasive Insects Cost the World Billions Per Year
04.10.2016 | University of Adelaide

nachricht Malaysia's unique freshwater mussels in danger
27.09.2016 | The University of Nottingham Malaysia Campus

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: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

Im Focus: Ultra-thin ferroelectric material for next-generation electronics

'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.

Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Resolving the mystery of preeclampsia

21.10.2016 | Health and Medicine

Stanford researchers create new special-purpose computer that may someday save us billions

21.10.2016 | Information Technology

From ancient fossils to future cars

21.10.2016 | Materials Sciences

More VideoLinks >>>