Optimizing Treatment of Cesspool Wastewater at an Activated Sludge Plant

Piotr Bugajski,Agnieszka Operacz,Dariusz Młyński,Karolina Kurek,Andrzej Wałęga

doi:10.3390/su122310196

Piotr Bugajski, Agnieszka Operacz + Show 3 more

Open Access

https://doi.org/10.3390/su122310196

Copy DOI

Journal: Sustainability	Publication Date: Dec 7, 2020
Citations: 2	License type: CC BY 4.0

Affiliation: University of Agriculture in Krakow

Abstract

The purpose of this work was to determine the optimal percentage of wastewater from cesspool in the mixture of wastes subjected to treatment processes, which will not have a negative impact on the functioning of the collective treatment plant. The study was carried out over a period of two years, with 48 samples of wastewater flowing in from the sewage network and delivered with the slurry tanker collected and subjected to physical and chemical analysis. The analysis included: Biochemical Oxygen Demand (BOD5), Chemical Oxygen Demand (COD), and Total Nitrogen (TN). In addition, the study defined the daily balance of the amount of inflowing and transported wastewater. Based on the analysis carried out, it was found that the unit loads of BOD5, COD and TN in the mixture of wastewater subjected to the treatment process will be at the level of loads assumed in the project, when the share of supplied wastewater, i.e., from cesspool, will be at the level of 5% of the total amount of wastewater. Considering that in the analysed period the total average daily amount of wastewater subjected to the treatment process was 253.5 m3·d−1, the optimal amount of wastewater delivered should be 12.7 m3 in each day of the week.

Highlights

Along with the growing expansion of housing construction in rural areas in Poland, the volume of water used by residents increases, the volume of generated sewage increases
The correct operation of such tanks consists in regular emptying of wastewater, which should be transported by a professional slurry tanker to a collective wastewater treatment plant, whose technological line is suitable to treat this type of wastewater
The average daily sewage inflow from the sewage network amounted to Q1 = 238.5 m3·d−1 to the said sewage treatment plant, while the average daily sewage delivered by the slurry tanker was Q2 = 15.1 m3·d−1, which constituted 5.7% of their share in the total amount of wastewater subjected to the treatment process

Summary

Introduction

Along with the growing expansion of housing construction in rural areas in Poland, the volume of water used by residents increases, the volume of generated sewage increases. In rural areas, according to current Central Statistical Office (CSO) data [1], in 2018 there were 21,775.50 thousand tanks for liquid waste, commonly known as cesspool. It still is the most common way of wastewater disposal in Poland, in rural areas where there are no collective or individual sewage systems. The main reason for this is the intention of users to reduce the costs of exporting and utilizing wastewater from cesspits in a collective treatment plant To prevent this type of practice, it is necessary to control the leak-tightness of this type of tanks and the regularity of their emptying by a professional company with the appropriate slurry tanker

Objectives

Methods

Results

Conclusion