Abstract. Detergents figure in an extensive array of industrial and home cleaning applications, released into the flow of wastewater coming from the home, can far-reaching environmental impacts. Microorganisms are crucial to nutrient recycling in ecosystems as they act as decomposers, pathogen, antibiotic producer, biodegradation of pollutants etc. The research is aimed to examine effect detergent disposal to bacterial population growth in marine environment both in vitro and in situ condition. Seawater samples were collected from Sungai Kayu Ara Village, and Dumai River estuary, Siak Regency and Dumai City, Riau Province. Experimental method with complete randomized design (RAL) 2 (two) factors; a detergent brand (a1: ATTACK, a2; RINSO and a3; SURF) and b concentration of detergent concentration with 5 (five) concentration level, b1 (0%) as control, b2 (0.3%), b3 (0.6%), b4 (0.9%) and b5 (1.2%) wass applied. The study showed that there was an effect of detergent addition, periode of exposure, and doses to the growth of bacterial population both in vitro and in situ conditions. The higher levels of detergent in the water column and the longer contamination duration, causing more and more depressed bacterial populations. It is suggested to run a further research on identification, and growth optimatioan of the species capable of degrading detergent.

This research was conducted in March 2020 at the Dumai River Estuary, Dumai City, Riau Province. The purpose of this study was to analyze the parameters of OT, BOD and TOM in the Dumai River Estuary; analyzing E. coli bacteria in the Dumai River Estuary and Determining the Level of Water Pollution Based on the Content of Organic Material Parameters and E. coli in the Dumai River Estuary. The data analysis method refers to OT (SNI 06.6989.14-2004), BOD (SNI 06-2503-2009), BOT (SNI 06-6989.22-2004) and E. coli (SNI 2897-2008). The results of measuring the parameters of organic matter content in the Dumai River Estuary, OT levels ranged from 4.1 - 4.6 mg /L, BOD5 levels ranged from 21.5 - 30.6 mg /L, the TOM content in The Dumai River Estuary ranges from 104 -165 mg /L and E. coli bacteria in the Dumai River Estuary ranges from 180 - 764 MPN /100 mL. The level of pollution at the Dumai River Estuary is based on the parameters of organic matter and E. coli content, including the criteria for light pollution

Input of nutrients into the waters from various human activities (residential, agriculture and industry) has the potential to cause changes in the physical, chemical and biological conditions of the waters. The study aims to determine the relationship of concentrations of nitrate, phosphate and silicate with the abundance of diatoms in the Tanjung Tiram waters. The method used is the survey method, the determination of the location of sampling is done by purposive sampling, data analysis (multiple regression). Based in the results of laboratory analysis nitrate concentrations ranged from 0,0819 – 0,1167 mg/l, the phosphate concentration ranged from 0,1002 – 0,1526 mg/l, and silicate concentration ranged from 0,04447 – 0,5418 mg/l. The abundance of diatoms in Tanjung Tiram waters ranged from 156,9 – 302,8 ind/l. The results of statistical analysis of the relationship of nitrate, phosphate and silicate with the abundance of diatoms are expressed in terms of equation Y = 350,906 – 58,065Nitrate– 2644,624phosphate+ 440,363Silicate. This statement explains the concentration of nitrate, phosphate related negative (-) to the abundance of diatoms and silicate positive (+) related to the abundance of diatom. This condition shows that the nutrient concentration in these waters is relatively high so that it affects the abundance of diatoms.

Organic matter is one indicator of environmental fertility either on land or at sea. Content Organic matter in the waters will experience an increase caused by discharges from households, agriculture, industry and organic waste from land to coast. The objective of this research is to know the content of organic material in water and sediment in the waters of Coast Mirror and the relation of organic matter content to water and sediment. The result of calculation of organic matter content in water ranged from 26.6 – 49.3 mg/l and the content of organic matter in sediment ranged from 3.9 – 5.1 %. Furthermore, through simple linear regression test known that the relationship of organic matter content in water and sediment has a weak relationship with the correlation r = 0.53. The analysis of sedimentary fractions in the pulau halang muka is dominated by muddy substrates.

Sungai Kayu Ara Village, Siak Regency, Riau Province is a coastal village. The main livelihoods of the people in this village are farming, fishermen and breeders. Pellets and concentrate feed have been used by the community as fish and livestock feed. But the high price of this feed makes this business less profitable. Azolla microphylla as fish feed and livestock has been introduced in Indonesia. This community service activity aims to train coastal communities of A. microphylla cultivation techniques which will later be used as fish feed and other livestock. This activity was carried out with the following stages; 1) Location survey, group formation and coordination. 2) Get off to the field and prepare sites for training. 3) Training of growing substrate fermentation techniques A. microphylla. 3) Training to prepare A. microphylla growing containers. 4) Cultivation training of A. microphylla. 5) Harvesting and giving A. microphylla to livestock. 6) Monitoring and evaluating the results of the trainings. A group of cultivators of A. microphylla has been formed and training has also been carried out with the students of the 2018 UNRI LPPM KKN participants in this village. This group named "SUKARELA" stands for the Sungai Kayu Ara Pemelihara Azolla with 30 members. Initial monitoring results in the second, third and fourth weeks after training showed that these macrophytes can grow well. Some members have enlarged the maintenance container in the form of maintenance tanks.