1.4 Why is Adequate Effluent Management Required?

Effluent Management 1 Introduction to Effluent Management 1.4 Why is Adequate Effluent Management Required?

Effluent from onsite sanitation or after the primary treatment by a faecal sludge treatment plant usually still contains various pollutants, which need to be reduced depending on the application or disposal route.

Let’s explore some of the effluent qualities collected in 2019 in Cox’s Bazar by UPM Umwelt Projekt Management GmbH (UPM) and analysed by UPM or partner laboratories.

Parameter	Anaerobic Baffled Reactor	Drying Bed (Lime pre-treatment)	Anaerobic Settler and Filter	Dewatering Geobag	Anaerobic Upflow Filter	Biogas Digester	Bangladesh Discharging Standards (ECR-2023 )	WASH Cluster recommend. for Discharge	Irrigation Standards WHO
Onsite / Offsite	Offsite	Offsite	Onsite	Offsite	Offsite	Onsite	–	–	–
Effluent Management	Collected in a pond, and discharged into a stream	Collected in a pond, and discharged into a stream	Discharged into channel	Discharged down the valley.	Soak pit	Collection pit, emptied and treated further	–	–	–
Temperature (°C)	31.9	23.2	22.2			27.6	≤ 30	–	–
pH	8.8	14	8.5	8.1	8.7	7.5	6 – 9	5 – 9	–
TSS (mg/L)	500	9,500	500	250	219	3,625	≤ 100	≤ 200	–
COD (mg/L)	400	13,600	1,875	3,850	1,275	6,780	≤125	≤ 250	–
BOD₅ (mg/L)	138	13,600	1,500	1,270	416	2,565	≤ 30	NA	–
TN (mg/L)	623	1,890	1,274	2,692	730	3,260	–	≤ 25	–
NH₄-N (mg/L)	352	1,890	89	1,063	30	1,075	–	–	–
NO₃ (mg/L)	–	–	–	–	–	–	≤ 50	–	–
TP (mg/L)	40	1,890	34	12	17	317	≤ 15	–	–
Oil and Grease (mg/L)	–	–	–	–	–	–	≤ 10	–	–
E.coli / TC (CFU/100mL)	200,000	1,890	300,000	500,000	3,000	2,000	≤ 1,000	≤ 1,000	≤ 1,000
Helminths (eggs/L)	nil	1,890	2,000	1,000	1,000	3,000	–	≤ 1	≤ 1

Effluent Characteristics

As the table illustrates, the effluent qualities from the different treatment plants do not meet the recommended standards, therefore post-treatment will still be required. The type of post-treatment will depend on the intended effluent management type and the desired quality. For example, agricultural use requires low pathogens to protect human and animal health, but nutrients are beneficial as they are required for plant growth. Suppose the effluent is intended to be discharged into a water body. In that case, the requirements for the post-treatment process are to reduce the nutrients and organics to prevent eutrophication and oxygen depletion as well as the pathogens.

To explore the effluent qualities achieved by faecal sludge treatment plants implemented in Cox’s Bazar, please visit the FSTP Effluent Quality Monitoring Dashboard.

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