[forumadmin]

Desiccated Coconut industry is a wide spread industry in the South Asian region. The wastewater generated during the production of desiccated coconut is having a good nutrition value for biogas production but it is harmful to the environment if released without treatment. This is a common problem in many coconut growing countries as that desiccated coconut manufacturing factories emit a high-strength, low-degradable wastewater having a low pH value.

This study was conducted in Sri Lanka, to investigate the applicability of a three-stage anaerobic filter (Up flow anaerobic floating filter–UAFF) system for wastewater treatment of desiccated coconut factories.

The experimental set-up was made with three anaerobic filter reactors coupled to a sedimentation tank and a biogas holder. The bacteria growing media is, coconut coir fibres, which facilitate granular bacteria formation, were installed inside the anaerobic digesters. Bacterial seeding was made from cow dung rich wastewater with Bacteria Growing Media. It achieved more than 90% of the removal rate for Chemical Oxygen Demand (COD), Biological Oxygen Demand (BOD) and turbidity, with an average organic loading rate of 1.25 kg COD/m3 day, for coconut wastewater as an influent, during the laboratory scale experiment. Average biogas yield was 2.5 litres (at atmospheric pressure and temperature) per litre of coconut wastewater per day with an average methane percentage of 65%.Hence the average biogas production from the wastewater of a DC mill would be 75m3/ day

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this discussion will be moderated by Engineer Athula Jayamanne M.Eng.(Bangkok-AIT), AMIE(SL), H.S.Mc.(Osaka), MIEP(SL),

he invites all interested individuals in the region to discuss potential applications of the technology in the South Asian region and also to share information on other similar technologies practised in South Asia.

the Discussion is conducted in collaboration with Sri Lanka Bio Gas Association

[arachchi_GSM]

I would like to have a cost comparison between, normally used (continuous type) bio gas unit and the novel bio gas unit with simillar capacity.
The other thing is, according to my knowledge waste water in desiccated coconut factories become low degradable due usage of Clorine to lower the percentage of micro organisms in the final product. Clorine is degradable when in sunlight . But in sri Lankan context Clorine contain Bromine as an impurity. Bromine is low degradable hence make the waste water low degradable. So improve the quality of Clorine make the waste water bio degradable may feed in to a continuous type bio gas unit which is common in Sri Lanka.

So the cost comparison and other benefits of novel bio gas unit over continuous type is very much apopreciated.
_________________
Gihan Sajeew Mathawarna Arachchi

[forumadmin]

to Dr Rathansiris querries
1. Is there any effect of dissolved fats on anaerobic digestion and specially biofilm formation on coir fibres.
So farwe have not faced any probems due to dissolved fats the anaerobic bacteria in cowdung is capable of digesting those dissolved fats.

2. Input pH is low in this waste water. Did you adjust pH before feeding to reactors. / 3. We conducted lab experiment using Desiccated coconut waste water under CSTR conditions, but could not recover pH as we did not adjust input pH.
Initially we have to adjust the PH value of input water by adding lime( CaCO3), but after two months we can avoid that by including a self adjusting mechanism( using a feed pump).

at Namiz
1). Can this technology be used in other types of waste waters such industrial waste with higher organic matter content?
Yes, as long as the chemical content in waste water is comparativley low we can use this method to any waste water with organic matter.

2). Compared to alternate uses of coconut water, is processing coconut water through a reactor attractive?
in Sri Lanka ( even in South Asia) we dont have factories that use methods to seperate the coconut water from the washing water and other anti bacterial liquids that is used in the production process of Desiccated Coconut. therefore there is very little use you can get from the waste water froma DC factory.

at Dommy
in the cases of the Garment factory and the hotel where the bio gas units were constructed what type of other chemicals were dissolved in the waste water ?.
Yes in both these cases there were disinfectants ( Harpic, soap water) mixed with the waste water but compared to the input water volume the amount is very low and we did not have any problems so far in those systems ( nearly 2 years).

have you tried this system in rubber sheet processing factories?
Yes, there are about 7 latex factroies now using this method.

- Athula Jayamanne.

[rathnasiri]

[namiz]

1). Can this technology be used in other types of waste waters such industrial waste with higher organic matter content?
2). Compared to alternate uses of coconut water, is processing coconut water through a reactor attractive?
I would be pleased to have a response from the moderator to the above two aspects please.

[dommy]

this is a very interesting methodology,

i would like to know from Mr Jayamanne in the cases of the Garment factory and the hotel where the bio gas units were constructed what type of other chemicals were dissolved in the waste water ?.

have you tried this system in rubber sheet processing factories?