Abstract:
Pressure on aquatic is now becoming heavier due to the contribution of residual
production discharges. Restaurants or domestic and tofu industry is one of the
biggest contributors. Restaurant wastewater is the most dominant because it
occupies about 60-70% of water bodies, while tofu industry is capable of producing
15-20 m3 of waste to process 1 ton of soybeans into tofu. Both of these activities can
produce large amounts of waste water and pollutants that contain nitrates and
phosphate as nutrients for the growth of microalgae such as Chlorella sp. This study
aims to look at the effect of a mixture of tofu and restaurant wastewater as a
fermented nutrient that is easily absorbed for the growth of Chlorella sp. This type of
microalgae has the ability to absorb carbon, produce oxygen, absorbent pollutants,
natural food, etc. The study was conducted in May 2019 using 5 different mixtures of
liquid waste and controls. Each unit had an operational volume of 3 liters, added
about 75ml of pure Chlorella sp. seeds and cultured for 7 days. Research results
show that the growth of Chlorella sp. increased from 1,008 x 109 cells/L to 7,461 x
109 cells/L in the temperature range of 30-40.6 oC with P5 (100%) treatment on the
5th day. The value of dissolved oxygen (DO) has increased from 2,67 mg/L to 5,50
mg/L. Chlorella sp. utilizing nitrate and phosphate so that it decreased from 8,1167
mg/L and 54,4137 mg/L to 0,128 mg/L and 14,508 mg/L. Peat media which has an
acidic pH range of 4-5 has increased to 8-9. The discoloration of water which was
originally yellowish to dark green, indicates that the nutrients from the waste mixture
can be an alternative nutrient in increasing the abundance of microalgae especially
Chlorella sp. in peat waters.
