Soil

In soil and waste samples diverse biolo­gical processes occur. They are especially based on conversion of organic carbon. Aerobic respi­ration tests and anaerobic fermen­tation tests can be used to evaluate waste samples. The German standard tests for waste deposits form the basis for this evaluation process.

 Respiration activity test (AT₄) (in accordance with the Ordinance on Environmentally Compatible Storage of Waste)

• The respi­ration activity (AT₄) assesses the potential of test material to be biolo­gi­cally decom­posed under aerobic condi­tions. The oxygen consumption per unit of time (e.g 4 or 7 days) is deter­mined in the process and compared with corre­sponding blank tests. The respi­ration activity is an important parameter in the waste deposit ordinance, for the treatment and deposit of mecha­ni­cally and biolo­gi­cally pre-treated waste amongst other things.
• We measure the AT₄ in batch test in accordance with the regula­tions of “Ordinance on Environ­men­tally Compa­tible Storage of Waste from Human Settle­ments and on Biolo­gical Waste-Treatment Facilities” with the automatic measu­rement system OxiTop^® (WTW).

Biogas potential test (Digester gas tests) (GB₂₁)

• Similar to breathing activity under aerobic condi­tions, the biogas potential test permits a statement on the ability and dynamic of a sample to be biolo­gi­cally decom­posed under anaerobic condi­tions. For this purpose the biolo­gical methane formation is automa­ti­cally analysed over a period of 21 days under anaerobic conditions.
• This parameter is important for operators of biogas plants, for example. It provides the operator or substrate supplier with infor­mation on how much biogas can be produced from a defined substrate during fermen­tation process.
• The fermen­tation test is conducted on the basis of German “DIN* 38414 Part 8” (German standard methods for the exami­nation of water, waste water and sludge). German standard tests on carrying out experi­ments can also be found in the “Ordinance on Environ­men­tally Compa­tible Storage of Waste from Human Settle­ments and on Biolo­gical Waste-Treatment Facilities“ and the VDI** Guideline 4630.

Composts must be regularly examined within the scope of the German RAL quality assurance system (RAL-GZ 251). The compost maturity (degree of rotting) is regulated in the German Compost Ordinance and provides infor­mation on the maturing of the substrate during the course of the composting process. The more mature a compost is, the less oxygen it consumes in a defined period.

This measu­rement is carried out with the automatic measu­rement system OxiTop^® (WTW). Measu­rement of the self-heating of the sample material in the Dewar container also provides infor­mation on the biolo­gical stability of the compost.

The bioche­mical oxygen demand for n days (BODn) is usually deter­mined during 5 days of incubation at 20°C. It represents the amount of oxygen needed for aerobic decom­posing processes of organic substances by micro­or­ga­nisms. The BOD therefore provides infor­mation on the biolo­gi­cally recyclable part of organic substances contained in a sample.

Diese Messung wird mit dem Messsystem OxiTop® (WTW) durchgeführt

Deter­mining the biode­gra­da­bility of lubri­cants and related products in accordance with DIN* 51828–2.

Inves­ti­gation of substances for easy biolo­gical decom­po­sition in accordance with the OECD guideline “Ready Biode­gra­da­bility” (301):

• The methods are suitable for proving fast and complete biode­g­radtion under aerobic condi­tions. The testing substance becomes carbon dioxide, water and bio mass through microbial degra­dation process. The basis is the deter­mi­nation of unspe­cific parameters such as dissolved organic carbon, biolo­gical oxygen demand and carbon dioxide evolution.

Inves­ti­gation of substances for biode­gra­dation potential in accordance with OECD Guideline “Inherent Biode­gra­da­bility” (302):

• The method is suitable for inves­ti­gating the inherent aerobic biode­gra­da­bility of organic substances even in the case of restricted ability to decompose of the test substances. It is parti­cu­larly useful for testing insoluble and/or volatile materials and based on the deter­mi­nation of the released organic carbon and the chemical oxygen demand.

We conduct individual testing possi­bi­lities in perco­lation pillars, circu­lation apparatus and individual experi­mental struc­tures going beyond the standard possi­bi­lities described.