Delphin Water Systems GmbH & Co. KG
Classification of the pollution degree of run-off water from agricultural surfaces

Description of the company
Delphin Water Systems GmbH & Co. KG in Buxtehude is one of the leading manufacturers of fully biological wastewater treatment plants with fixed-bed technology. Our business activities include the dimensioning and delivery of pre-assembled small scale WWTP, compact WWTP and WWTP in containers as well as services related to decentralized wastewater treatment, such as installation, maintenance, optimization and operation management.

Initial situation

In the surroundings of biogas plants and holding areas, differently polluted rainwater results as run-off water from dirty silo surfaces, manoeuvring areas and hoppers during heavy rain fall. Due to a faulty assumption during the planning of such sealed agricultural operating areas, the pollution of rainwater could be avoided by plastic coverings and a frequent manual cleaning, there is now need for urgent action in many places.
In operational practice, rainwater is contaminated, falling on open silages (e.g., in the gate area of the silo) and on roads contaminated with silage residues (e.g., corn silage) and animal excrement.
The previous practice of discharging these waters into the receiving waters or through undefined drainages into the environment leads to water pollution that is noticed and reported by residents or responsible water authorities.
Many farmers have recognized this problem and their liability risk and are collecting the polluted rainwater in liner ponds or underground storage tanks.
From these collection containers, the water is discharged together with the digestate or the manure of the farm in the permitted times for fertilization on farmland and green areas.
Due to increasing rainfall in the winter months and the then valid fertilizer-blocking period, the storage possibilities are no longer sufficient, and the collected water must be disposed of at high costs.
The discharge of collected rainwater is also associated with personnel and energy costs, which can be reduced using a biological treatment plant and the then possible direct discharge into a natural water body.

Particularly fluctuating loads, temperatures and hydraulics make it difficult to treat these precipitation waters. The highly polluted waste water that occurs occasionally cannot be treated with a biological wastewater treatment plant designed for average loads and contains energy-usable loads that must be separated from the moderately polluted waters.

Delphin Water Systems wants to offer a solution to this problem through a new development - a targeted separation of the heavily loaded partial streams. From preliminary studies it is known that the conductivity is a good parameter to be able to determine the degree of contamination of silage eluates. In the high value ranges (COD > 10,000 mg/l) a good correlation between COD and conductivity was found. However, the COD values for a technically sensible respectively cost-effective biological treatment are in the low range (COD < 1,500 mg/l), in which the correlation with the conductivity is disturbed by other influences. Furthermore, the time courses of the values are largely unknown and therefore it is not possible to make any statements in advance about the expected "selectivity" and the separation efficiency of the separation system.

Aims of the project
1.      Detection and presentation of the time course of the COD concentration and the conductivity as a function of the actual rain events.
2.      Balancing of flows and loads
3.      Definition of classification characteristics of agricultural areas regarding the expected degree of pollution.
4.      Prediction of the theoretical degree of separation using a classification system for agricultural areas.

1.      Assembly and on-site installation of a measuring device for the detection of flows and conductivity values
2.      Development of a technical solution for the online recording of rain events
3.      Carry out of sampling and laboratory analyses
4.      Merging and evaluation of determined measured values and data
5.      Balancing and determination of treatment plant design relevant parameters
6.      Inspection and development of classification characteristics of agricultural areas
7.      Development of a calculation model for predicting the efficiency of a separation system

Target group (students)
Students and graduates (up to 2 years after graduation) from all disciplines of HAW Hamburg, the University of Hamburg and the TU Hamburg-Harburg. In particular, students and graduates in the fields of water and environmental engineering, civil and environmental engineering, energy and environmental technology, renewable energies, process engineering, information and electrical engineering and industrial engineering are encouraged to apply for this project

Please reserve these dates:

  • 11 April: Information event with te companies, from 10am to 12pm, mainbuilding A; LuK
  • 18 April: Kick-off event, from 2pm to 6pm (obligatory attendance)
  • 21 and 28 April: Project management course, full day (obligatory attendance)