SEWAGE SLUDGE DISPOSAL - A summary with a status report

basis

The community of Augustdorf operates the Augustdorf sewage treatment plant, Waldstrasse 233. It has to dispose of the sewage sludge (currently approx. 1,000 t / a, amount after decanter: approx. 20% dry matter).

Disposal has become more and more difficult and expensive in recent years. For the most cost-effective application on agricultural land until 2016, which will prevail in Lippe, there are in some cases no longer any offers or offers over € 100 per tonne of sewage sludge.

The background to this is the Waste Sewage Sludge Ordinance, which was amended in 2017, and the Fertilizer Ordinance, which was amended in 2017.

The Waste Sewage Sludge Ordinance contains, among other things, deadlines for implementation until 2029, which relate in particular to the withdrawal from agricultural application and the obligation to recycle phosphorus for sewage sludge from municipal wastewater treatment. Due to the tightening of the Fertilizer Ordinance 2017, farmers are not interested or because of the restrictions (limit values for pollutants and maximum amounts for nutrients lowered, ban on application in water protection areas, etc.). A further tightening of the fertilizer ordinance is currently in the vote, also due to the sanctions imposed by the EU.

The solar sewage sludge drying was carried out without subsidies, with a loan “Kommunal. Invest NRW. Bank ”and put into operation in autumn 2017.

The aim of the construction of this plant (with unanimous political resolution and approval of the Detmold district government, with previous audits) was to keep the costs for sewage sludge disposal low after changing the Sewage Sludge Ordinance NRW / Fertilizer Ordinance NRW by significantly reducing the amount of sewage sludge ( from 1,000 t / a to 350 t / a). The wastewater charges should and should be kept low.

In order to secure the sewage sludge disposal of the community of Augustdorf in the long term, the AWV will take over the task of sewage sludge disposal in addition to waste disposal from 2024. This means a joint disposal of sewage sludge between AWV Lippe and over 70 other cooperation partners from the OWL region. Bundling creates synergies in terms of price and procedures. The aim is to ensure a sustainable, economical, environmentally friendly, legally secured and fee-stable sewage sludge disposal. The AWV sets a uniform price and bills according to the quantity. The costs of sewage sludge disposal can be included in the “dirty water” fee calculation in accordance with Section 6 of the KAG NRW.

Complaint residents odor / noise nuisance

“With the system, the overall view of the sewage treatment plant must be the focus.

The sewage sludge drying plant (approval from the district government from 09.09. 2016) is being gradually optimized in the trial operation of the exhaust air towers (approval from the district government Detmold from 14.10.2019) in accordance with the requirements and ancillary provisions of the permits. The sewage treatment plant was also erected in front of the adjacent housing estate in terms of time. "

In the first phase (autumn-spring), however, there was hardly any drying performance due to the weather. So the hall had to be cleared and the "wet" sewage sludge removed.

The strong, persistent smells resulted from the increased ammonia emissions of the "wet" sewage sludge, especially during the clearing and removal of the sewage sludge. It was also found that the air fans had temporarily failed. The direction of the wind supports the spread of the smell in the housing estate.

The Detmold district government was called in and an on-site visit was held at the sewage treatment plant to find a solution. The sewage treatment plant is to be viewed as a whole in terms of odor emissions. After the report and the requirements of the district government are available, the necessary measures should be carried out immediately.

In September 2018, the engineering office Uppenkamp & Partner from Ahaus carried out the following measurements at the Augustdorf sewage treatment plant:

• Odor emission measurement of the complete sewage treatment plant including the solar sewage sludge drying system.

Result:

Construction of the exhaust air towers

• Noise emission measurement of the turning unit (electric pig) of the solar sewage sludge drying plant.

Result:

The report produced does not determine any increased values here. The noise development is far below the permissible limit values.

By optimizing the electronic control, the movements of the turning unit have been adapted to the legally permissible working hours on workdays, Sundays and public holidays.

In order to get reliable results and to achieve the optimal result in a target-oriented manner, sufficient trial operation is required. Time is of the essence in every way.

On the basis of current, unanimously decided political resolutions and the approval of the immediate completion of the trial operation of the exhaust air chimneys by the Detmold district government, we have been in trial operation since May 2020.

Various procedural changes have been and are still being made.

Measurements of the emissions take place in parallel and are being expanded by the supervisory authority. Further process optimizations are being carried out in close coordination with the Detmold district government.

A process has to be optimized, which depends on many procedural, physical, chemical, meteorological, social and other factors. A result can only be achieved through an analytically controlled, step-by-step approach. Then act in the same way.

After the chimneys have been completed and after a sufficient trial run, a residents' meeting may have to be held at the sewage treatment plant.

In coordination with the responsible legal department of the Detmold district government, an application was made on April 1st, 2020 for the immediate execution of the approval notice in accordance with Section 80a, Paragraph 1, No. 1 in conjunction with Section 80, Paragraph 2, No. 4 of the Administrative Court Regulations (VwGO) .

Status overview:

• Trial operation has been running since 05.2020

• On May 5th, 2020 we received immediate execution from the district government.

• On March 20th, 2020, a lawsuit against the Detmold district government, including the municipality of Augustdorf, was filed with the Minden Administrative Court because of the approval for the construction and operation of a solar sewage sludge drying plant / drift effect.

• In the 32nd week of 2020, dry sewage sludge was separated in the solar sewage sludge drying hall in compliance with the occupational health and safety regulations. The sewage sludge was brought into the first third of the drying hall by means of a wheel loader.

• Since mid-July 2020, a "spray mist" has been introduced via spray nozzles directly in front of the exhaust chimneys in order to bind dust and minimize odor. The odor emissions have been significantly reduced, but have not been stopped.

• From July 28, 2020, in coordination with the Detmold district government, anionic surfactants have been added to the “spray mist”. Here, too, the odor leakage was significantly lower, but also not ended.

• Further process changes have been successfully tested from week 34, 2020. An effective spray device will be installed in the chimneys from mid-November 2020 in order to effectively neutralize the odor with the spray mist, to which multiple sugars are then added.

• All procedural changes in the trial run must be planned and approved by the Detmold district government, the necessary technical components must be procured and specialist companies must install the respective technical changes. Therefore, the period in which changes occur is always a little longer.

• At the beginning of September, a measuring nozzle will be installed in the chimneys to measure the air concentration there. The measurement is carried out by an expert office. This procedure has been ordered by the Detmold district government.

• Subsequently, further odor measurements in the residential area will be carried out by the Detmold district government.

• With regard to the noise emissions in the adjacent area, reference is made to the noise report by Uppenkamp & Partner. Accordingly, the municipal utilities comply with the limit values.

• On August 12, 2020, the Detmold district government took noise measurements at the plaintiff's.

• In the 34th week of 2020, an attempt to eliminate the odors was successfully carried out.

• The technical installations will be completed by the end of November 2020 (due to the long delivery times for special parts).

• From December 2020, the exhaust air system of the solar sewage sludge drying system is to be in use in accordance with the current permits and the ancillary provisions contained therein.

Effects of a possible closure of the facility

The final consideration of the auditor's office is not yet available.

But the closure of the plant is a total loss. This loss must be compensated for over the next few years. How this will happen has not yet been determined, but the citizen will then have to bear the compensation either through fees or taxes.